[ { "id": "https://authors.library.caltech.edu/records/aprev-2xs06", "eprint_status": "archive", "datestamp": "2024-01-31 23:53:39", "lastmod": "2024-01-31 23:53:39", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Aitbekova-Aisulu", "name": { "family": "Aitbekova", "given": "Aisulu" }, "orcid": "0000-0003-3309-1220" }, { "id": "Watkins-Nicholas", "name": { "family": "Watkins", "given": "Nicholas" }, "orcid": "0000-0001-7251-9387" }, { "id": "Richter-Matthias-H", "name": { "family": "Richter", "given": "Matthias H." }, "orcid": "0000-0003-0091-2045" }, { "id": "Jahelka-Phillip", "name": { "family": "Jahelka", "given": "Phillip" }, "orcid": "0000-0002-1460-7933" }, { "id": "Peters-J-C", "name": { "family": "Peters", "given": "Jonas C." }, "orcid": "0000-0002-6610-4414" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Atwater-H-A", "name": { "family": "Atwater", "given": "Harry A." }, "orcid": "0000-0001-9435-0201" } ] }, "title": "Molecular Additives Improve the Selectivity of CO\u2082 Photoelectrochemical Reduction over Gold Nanoparticles on Gallium Nitride", "ispublished": "pub", "full_text_status": "public", "keywords": "Mechanical Engineering; Condensed Matter Physics; General Materials Science; General Chemistry; Bioengineering", "note": "
© 2024 American Chemical Society.
\n\nThis material is based on work performed by the Liquid Sunlight Alliance, which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Fuels from Sunlight Hub, under Grant DE-SC0021266. Part of this work was carried out at the Molecular Materials Research Center in the Beckman Institute of the California Institute of Technology. The Resnick Sustainability Institute is acknowledged for support of enabling facilities at Caltech. The authors thank Yungchieh Lai for performing ICP-MS measurements and Azhar Carim for helping collect cross-sectional SEM data. A.A. acknowledges support from the Kavli Nanoscience Institute Postdoctoral Fellowship.
\nThe authors declare no competing financial interest.
", "abstract": "Photoelectrochemical CO2 reduction (CO2R) is an appealing solution for converting carbon dioxide into higher-value products. However, CO2R in aqueous electrolytes suffers from poor selectivity due to the competitive hydrogen evolution reaction that is dominant on semiconductor surfaces in aqueous electrolytes. We demonstrate that functionalizing gold/p-type gallium nitride devices with a film derived from diphenyliodonium triflate suppresses hydrogen generation from 90% to 18%. As a result, we observe increases in the Faradaic efficiency and partial current density for carbon monoxide of 50% and 3-fold, respectively. Furthermore, we demonstrate through optical absorption measurements that the molecular film employed herein, regardless of thickness, does not affect the photocathode’s light absorption. Altogether, this study provides a rigorous platform for elucidating the catalytic structure–property relationships to enable engineering of active, stable, and selective materials for photoelectrochemical CO2R.
\n© 2024 The Authors. Published by American Chemical Society. This publication is licensed under CC-BY-NC-ND 4.0.
\n\nT.A. is grateful to the talented students and postdoctoral scholars who have contributed to projects on multimetallic complexes related to protein active sites developed in the Agapie lab, some of which are included in this Perspective, and to collaborators who have studied these compounds and helped understand their properties. T.A. thanks the NIH (R01-GM102687B) and NSF (CHE-1905320) for generously funding research related to bioinorganic chemistry in his laboratory.
\nThe authors declare no competing financial interest.
", "abstract": "Metalloenzymes with heteromultimetallic active sites perform chemical reactions that control several biogeochemical cycles. Transformations catalyzed by such enzymes include dioxygen generation and reduction, dinitrogen reduction, and carbon dioxide reduction–instrumental transformations for progress in the context of artificial photosynthesis and sustainable fertilizer production. While the roles of the respective metals are of interest in all these enzymatic transformations, they share a common factor in the transfer of one or multiple redox equivalents. In light of this feature, it is surprising to find that incorporation of redox-inactive metals into the active site of such an enzyme is critical to its function. To illustrate, the presence of a redox-inactive Ca2+ center is crucial in the Oxygen Evolving Complex, and yet particularly intriguing given that the transformation catalyzed by this cluster is a redox process involving four electrons. Therefore, the effects of redox inactive metals on redox processes–electron transfer, oxygen- and hydrogen-atom transfer, and O–O bond cleavage and formation reactions–mediated by transition metals have been studied extensively. Significant effects of redox inactive metals have been observed on these redox transformations; linear free energy correlations between Lewis acidity and the redox properties of synthetic model complexes are observed for several reactions. In this Perspective, these effects and their relevance to multielectron processes will be discussed.
\n\u00a9 2023 The Authors. Published by American Chemical Society. This publication is licensed under CC-BY 4.0.
\n\nWe are grateful to Dow (TA) for funding. We thank Alex J. Nett and Todd D. Senecal for insightful discussions. We thank Manar M. Shoshani, Linh N.V. Le, Michael Takase, and Matthew R. Espinosa for assistance with X-ray crystallography and David VanderVelde for assistance with NMR spectroscopy. We thank Heidi Clements for assistance in collecting polymer characterization data (GPC, DSC, and FT-IR). Support has been provided for the X-ray diffraction and NMR instrumentation via the Dow Next Generation Educator Fund.
\n\nThe manuscript was written through contributions of all authors.
\n\nThe authors declare no competing financial interest.
\n\nCCDC 2280179\u201381 contain the supplementary crystallographic data for this paper.
", "abstract": "Polar monomer-induced \u03b2-H elimination is a key elementary step in polar polyolefin synthesis by coordination polymerization but remains underexplored. Herein, we show that a bulky neutral Ni catalyst, 1^(Ph), is not only a high-performance catalyst in ethylene/acrylate copolymerization (activity up to \u223c37,000 kg/(mol\u00b7h) at 130 \u00b0C in a batch reactor, mol % tBA \u223c 0.3) but also a suitable platform for investigation of acrylate-induced \u03b2-H elimination. 4^(Ph-tBu), a novel Ni alkyl complex generated after acrylate-induced \u03b2-H elimination and subsequent acrylate insertion, was identified and characterized by crystallography. A combination of catalysis and mechanistic studies reveals effects of the acrylate monomer, bidentate ligand, and the labile ligand (e.g., pyridine) on the kinetics of \u03b2-H elimination, the role of \u03b2-H elimination in copolymerization catalysis as a chain-termination pathway, and its potential in controlling the polymer microstructure in polar polyolefin synthesis.
", "date": "2023-12-06", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "145", "number": "48", "publisher": "American Chemical Society", "pagerange": "26463-26471", "issn": "0002-7863", "official_url": "https://authors.library.caltech.edu/records/4qs6g-1e845", "funders": { "items": [ { "grant_number": "Dow Next Generation Educator Fund" } ] }, "doi": "10.1021/jacs.3c10800", "pmcid": "PMC10704591", "primary_object": { "basename": "ja3c10800.pdf", "url": "https://authors.library.caltech.edu/records/4qs6g-1e845/files/ja3c10800.pdf" }, "related_objects": [ { "basename": "ja3c10800_si_001.pdf", "url": "https://authors.library.caltech.edu/records/4qs6g-1e845/files/ja3c10800_si_001.pdf" } ], "resource_type": "article", "pub_year": "2023", "author_list": "Xiong, Shuoyan; Hong, Alexandria; et el." }, { "id": "https://authors.library.caltech.edu/records/1jgaq-fwz19", "eprint_status": "archive", "datestamp": "2023-09-22 18:27:32", "lastmod": "2023-09-22 18:27:32", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xiong-Shuoyan", "name": { "family": "Xiong", "given": "Shuoyan" }, "orcid": "0000-0002-2579-4260" }, { "id": "Shoshani-Manar-M", "name": { "family": "Shoshani", "given": "Manar M." }, "orcid": "0000-0002-4051-3367" }, { "id": "Nett-Alex-J", "name": { "family": "Nett", "given": "Alex J." }, "orcid": "0000-0003-0209-0292" }, { "id": "Spinney-Heather-A", "name": { "family": "Spinney", "given": "Heather A." } }, { "id": "Henderson-Briana-S", "name": { "family": "Henderson", "given": "Briana S." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Nickel-Based Heterometallic Catalysts for Ethylene-Acrylate Copolymerization: Interrogating Effects of Secondary Metal Additives", "ispublished": "pub", "full_text_status": "public", "keywords": "Inorganic Chemistry; Organic Chemistry; Physical and Theoretical Chemistry", "note": "\u00a9 2023 American Chemical Society.
\n\nWe are grateful to Dow (TA) for funding. We thank Brad C. Bailey and Todd D. Senecal for insightful discussions. We thank Michael K. Takase and Lawrence Henling for assistance with X-ray crystallography and David VanderVelde for assistance with NMR spectroscopy. We thank Hannah Bailey and Heidi Clements for assistance in collecting polymer characterization data (GPC, DSC, and FT-IR). Support has been provided for the X-ray diffraction and NMR instrumentation via the Dow Next Generation Educator Fund.
\n\nThe authors declare no competing financial interest.
", "abstract": "A class of in situ-generated Ni-based multimetallic complexes based on a bisphosphine phenoxide ligand (POP) was studied for ethylene-acrylate copolymerization. Starting from a previously prepared Ni-POP complex, addition of several metal precursors results in coordination involving the second phosphine not bound to Ni. These isolated complexes show lower copolymerization activity compared to Ni-POP. Structural characterization of relevant bimetallic complexes shows ancillary ligand binding in a PO-bidentate fashion to each metal with phenoxide bridging. Additionally, halide bridges are observed in several complexes, highlighting a potential inhibition mechanism by binding to Ni. In contrast, in situ addition of Al(O\u1da6Pr)\u2083 as a secondary metal results in an increase in activity for ethylene/acrylate copolymerization while maintaining high levels of acrylate incorporation. Overall, these results demonstrate various effects in bimetallic systems for polymerization catalysis relevant to future catalyst design.
", "date": "2023-09-11", "date_type": "published", "publication": "Organometallics", "publisher": "American Chemical Society", "issn": "0276-7333", "official_url": "https://authors.library.caltech.edu/records/1jgaq-fwz19", "funders": { "items": [ {} ] }, "doi": "10.1021/acs.organomet.3c00307", "primary_object": { "basename": "om3c00307_si_001.pdf", "url": "https://authors.library.caltech.edu/records/1jgaq-fwz19/files/om3c00307_si_001.pdf" }, "resource_type": "article", "pub_year": "2023", "author_list": "Xiong, Shuoyan; Shoshani, Manar M.; et el." }, { "id": "https://authors.library.caltech.edu/records/fkwtj-ts532", "eprint_id": 122211, "eprint_status": "archive", "datestamp": "2023-10-19 17:22:27", "lastmod": "2023-10-19 17:22:27", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Shiau-Angela-A", "name": { "family": "Shiau", "given": "Angela A." } }, { "id": "Lee-Heui-Beom", "name": { "family": "Lee", "given": "Heui Beom" } }, { "id": "Oyala-Paul-H", "name": { "family": "Oyala", "given": "Paul H." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Coordination Number in High-Spin\u2013Low-Spin Equilibrium in Cluster Models of the S\u2082 State of the Oxygen Evolving Complex", "ispublished": "pub", "full_text_status": "public", "keywords": "Colloid and Surface Chemistry; Biochemistry; General Chemistry; Catalysis", "note": "\u00a9 2023 American Chemical Society. \n\nThis research was supported by the NIH, R01-GM102687B. We thank the Beckman Institute at Caltech and the Dow Next Generation Educator Fund for instrumentation support. Magnetic data was acquired on a SQUID supported by the NSF MRI-1625776 at UCLA. We thank Michael Takase, Matthew Espinosa, and Lawrence Henling for assistance with X-ray crystallography and Ignacio Martini with SQUID magnetometry. We thank Tianyi He for providing the silicate precursor used for accessing 4-ox-H\u2082O.", "abstract": "The S\u2082 state of the Oxygen Evolving Complex (OEC) of Photosystem II (PSII) shows high-spin (HS) and low-spin (LS) EPR signals attributed to distinct structures based on computation. Five-coordinate Mn^(III) centers are proposed in these species but are absent in available spectroscopic model complexes. Herein, we report the synthesis, crystal structure, electrochemistry, SQUID magnetometry, and EPR spectroscopy of a Mn^(III)Mn^(IV)\u2083O\u2084 cuboidal complex featuring five-coordinate Mn^(III). This cluster displays a spin ground state of S = 5/2, while conversion to a six-coordinate Mn upon treatment with water results in a spin state change to S = 1/2. These results demonstrate that coordination number, without dramatic changes within the Mn\u2084O\u2084 core, has a substantial effect on spectroscopy.
", "date": "2023-07-12", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "145", "number": "27", "publisher": "American Chemical Society", "pagerange": "14592-14598", "id_number": "CaltechAUTHORS:20230710-599244800.25", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230710-599244800.25", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687B" }, { "agency": "Caltech Beckman Institute" }, { "agency": "Dow Next Generation Educator Fund" }, { "agency": "NSF", "grant_number": "CHE-1625776" } ] }, "doi": "10.1021/jacs.3c04464", "pmcid": "PMC10575483", "primary_object": { "basename": "nihms-1933061.pdf", "url": "https://authors.library.caltech.edu/records/fkwtj-ts532/files/nihms-1933061.pdf" }, "related_objects": [ { "basename": "NIHMS1933061-supplement-ja3c04464_si_001.pdf", "url": "https://authors.library.caltech.edu/records/fkwtj-ts532/files/NIHMS1933061-supplement-ja3c04464_si_001.pdf" } ], "resource_type": "article", "pub_year": "2023", "author_list": "Shiau, Angela A.; Lee, Heui Beom; et el." }, { "id": "https://authors.library.caltech.edu/records/xdy8w-0tc45", "eprint_id": 122296, "eprint_status": "archive", "datestamp": "2023-08-22 21:21:13", "lastmod": "2023-10-20 20:25:22", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Bruening-Meaghan-A", "name": { "family": "Bruening", "given": "Meaghan A." } }, { "id": "Xiong-Shuoyan", "name": { "family": "Xiong", "given": "Shuoyan" }, "orcid": "0000-0002-2579-4260" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "\u03b1,\u03c9-Diene Generation from Ethylene and Butadiene by Copolymer Upcycling", "ispublished": "pub", "full_text_status": "public", "keywords": "Renewable Energy, Sustainability and the Environment; General Chemical Engineering; Environmental Chemistry; General Chemistry", "note": "\u00a9 2023 American Chemical Society. \n\nWe are grateful to the Resnick Sustainability Institute at Caltech for financial support. We thank David VanderVelde for assistance with NMR spectroscopy. We thank the Dow Next Generation Educator Fund for support of NMR instrumentation. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - sc3c02569_si_001.pdf
", "abstract": "Linear \u03b1-olefins are accessed efficiently from ethylene in the Shell higher olefin process (SHOP), an industrial process practiced on a million-ton scale that generates a statistical mixture of C\u2084-C\u2083\u2080 products. An analogous general process for the preparation of a range of \u03b1,\u03c9-dienes is lacking. We herein report a two-step method that generates industrially relevant \u03b1,\u03c9-dienes. In the first step, ethylene and butadiene are copolymerized to generate copolymers with a variable butadiene content. A titanium bisphenoxide bisthiolate catalyst activated with methylaluminoxane (MAO) was selected for this step due to the high selectivity for 1,4-butadiene incorporation. Ethenolysis of the copolymers results in a distribution of \u03b1,\u03c9-dienes in the C\u2081\u2080-C\u2082\u2080 range. Depending on the conditions, linear trienes are also generated. The reported protocol provides a strategy for copolymer upcycling to value-added olefin products.", "date": "2023-07-10", "date_type": "published", "publication": "ACS Sustainable Chemistry & Engineering", "volume": "11", "number": "27", "publisher": "American Chemical Society", "pagerange": "9918-9923", "id_number": "CaltechAUTHORS:20230717-49907100.1", "issn": "2168-0485", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230717-49907100.1", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Resnick Sustainability Institute" }, { "agency": "Dow Next Generation Educator Fund" } ] }, "local_group": { "items": [ { "id": "Resnick-Sustainability-Institute" } ] }, "doi": "10.1021/acssuschemeng.3c02569", "primary_object": { "basename": "sc3c02569_si_001.pdf", "url": "https://authors.library.caltech.edu/records/xdy8w-0tc45/files/sc3c02569_si_001.pdf" }, "resource_type": "article", "pub_year": "2023", "author_list": "Bruening, Meaghan A.; Xiong, Shuoyan; et el." }, { "id": "https://authors.library.caltech.edu/records/mxr3m-q3p21", "eprint_id": 121301, "eprint_status": "archive", "datestamp": "2023-08-22 20:56:23", "lastmod": "2023-10-20 15:24:56", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Watkins-Nicholas-B", "name": { "family": "Watkins", "given": "Nicholas B." }, "orcid": "0000-0001-7251-9387" }, { "id": "Schiffer-Zachary-J", "name": { "family": "Schiffer", "given": "Zachary J." }, "orcid": "0000-0001-6069-8613" }, { "id": "Lai-Yungchieh", "name": { "family": "Lai", "given": "Yungchieh" }, "orcid": "0000-0001-9392-1447" }, { "id": "Musgrave-Charles-B-III", "name": { "family": "Musgrave", "given": "Charles B., III" }, "orcid": "0000-0002-3432-0817" }, { "id": "Atwater-H-A", "name": { "family": "Atwater", "given": "Harry A." }, "orcid": "0000-0001-9435-0201" }, { "id": "Goddard-W-A-III", "name": { "family": "Goddard", "given": "William A., III" }, "orcid": "0000-0003-0097-5716" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Peters-J-C", "name": { "family": "Peters", "given": "Jonas C." }, "orcid": "0000-0002-6610-4414" }, { "id": "Gregoire-J-M", "name": { "family": "Gregoire", "given": "John M." }, "orcid": "0000-0002-2863-5265" } ] }, "title": "Hydrodynamics Change Tafel Slopes in Electrochemical CO\u2082 Reduction on Copper", "ispublished": "pub", "full_text_status": "public", "keywords": "Materials Chemistry; Energy Engineering and Power Technology; Fuel Technology; Renewable Energy, Sustainability and the Environment; Chemistry (miscellaneous)", "note": "\u00a9 2023 The Authors. Published by American Chemical Society. Attribution 4.0 International (CC BY 4.0).\n\nThis material is based on work performed by the Liquid Sunlight Alliance, which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Fuels from Sunlight Hub under Award Number DE-SC0021266. The Resnick Sustainability Institute at Caltech is acknowledged for its support of enabling infrastructure and facilities. We thank Dr. Ian Sullivan for many productive conversations and Annette Boehme for initial insights into COMSOL calculations of the cells investigated. \n\nN.B.W. and Z.J.S. contributed equally to this work. \n\nThe authors declare no competing financial interest.\n\nPublished - acsenergylett.3c00442.pdf
Supplemental Material - nz3c00442_si_001.pdf
", "abstract": "The hydrodynamics of electrochemical CO\u2082 reduction (CO\u2082R) systems is an insufficiently investigated area of research that has broad implications on catalyst activity and selectivity. While most previous reports are limited to laminar and CO\u2082-sparged systems, herein we address a wide range of hydrodynamics via electrolyte recirculation systems. We find that increased hydrodynamics at the electrode surface results directly in changes to the ethylene and methane Tafel slopes, demonstrating that mass transport is on equal footing with catalyst active sites in determining reaction mechanisms and the ensuing product distribution. Mass transport is traditionally considered to be in the purview of systems-level engineering, yet the present work shows that CO\u2082R mechanistic work must be considered in the context of the mass transport conditions. We extend our analysis to organic coatings, demonstrating that the films shield the active sites from variability in hydrodynamics and increase the residence time of CO so that it may be further reduced to desirable products.", "date": "2023-05-12", "date_type": "published", "publication": "ACS Energy Letters", "volume": "8", "number": "5", "publisher": "American Chemical Society", "pagerange": "2185-2192", "id_number": "CaltechAUTHORS:20230502-856709200.5", "issn": "2380-8195", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230502-856709200.5", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0021266" } ] }, "other_numbering_system": { "items": [ { "id": "1567", "name": "WAG" } ] }, "local_group": { "items": [ { "id": "Liquid-Sunlight-Alliance" }, { "id": "Resnick-Sustainability-Institute" } ] }, "doi": "10.1021/acsenergylett.3c00442", "primary_object": { "basename": "nz3c00442_si_001.pdf", "url": "https://authors.library.caltech.edu/records/mxr3m-q3p21/files/nz3c00442_si_001.pdf" }, "related_objects": [ { "basename": "acsenergylett.3c00442.pdf", "url": "https://authors.library.caltech.edu/records/mxr3m-q3p21/files/acsenergylett.3c00442.pdf" } ], "resource_type": "article", "pub_year": "2023", "author_list": "Watkins, Nicholas B.; Schiffer, Zachary J.; et el." }, { "id": "https://authors.library.caltech.edu/records/93ew7-17s20", "eprint_id": 119875, "eprint_status": "archive", "datestamp": "2023-08-22 20:22:06", "lastmod": "2023-10-25 16:46:51", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Nie-Weixuan", "name": { "family": "Nie", "given": "Weixuan" }, "orcid": "0000-0003-2094-6840" }, { "id": "Heim-Gavin-P", "name": { "family": "Heim", "given": "Gavin P." }, "orcid": "0000-0002-9244-6565" }, { "id": "Watkins-Nicholas-B", "name": { "family": "Watkins", "given": "Nicholas B." }, "orcid": "0000-0001-7251-9387" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Peters-J-C", "name": { "family": "Peters", "given": "Jonas C." }, "orcid": "0000-0002-6610-4414" } ] }, "title": "Organic Additive-derived Films on Cu Electrodes Promote Electrochemical CO\u2082 Reduction to C\u2082\u208a Products Under Strongly Acidic Conditions", "ispublished": "pub", "full_text_status": "public", "keywords": "General Chemistry; Catalysis", "note": "\u00a9 2023 Wiley-VCH. \n\nThis material is based on work performed by the Liquid Sunlight Alliance, which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Fuels from Sunlight Hub under Award Number DE-SC0021266. The Resnick Sustainability Institute at Caltech is also acknowledged for its support of enabling infrastructure and facilities. We thank Dr. Yueshen Wu for SEM measurement assistance. We thank Dr. Shaoyang Lin for GC-MS measurement assistance. \n\nData Availability Statement. The data that support the findings of this study are available in the Supporting Information of this article. \n\nThe authors declare no conflict of interest.", "abstract": "Electrochemical CO\u2082 reduction (CO\u2082R) at low pH is desired for high CO\u2082 utilization; the competing hydrogen evolution reaction (HER) remains a challenge. High alkali cation concentration at a high operating current density has recently been used to promote electrochemical CO\u2082R at low pH. Herein we report an alternative approach to selective CO\u2082R (>70\u2009% Faradaic efficiency for C\u2082\u208a products, FE_(C2+)) at low pH (pH\u20052; H\u2083PO\u2084/KH\u2082PO\u2084) and low potassium concentration ([K\u207a]=0.1\u2005M) using organic film-modified polycrystalline copper (Modified-Cu). Such an electrode effectively mitigates HER due to attenuated proton transport. Modified-Cu still achieves high FE_(C2+) (45\u2009% with Cu foil /55\u2009% with Cu GDE) under 1.0\u2005M H\u2083PO\u2084 (pH\u22481) at low [K\u207a] (0.1\u2005M), even at low operating current, conditions where HER can otherwise dominate.", "date": "2023-03-13", "date_type": "published", "publication": "Angewandte Chemie International Edition", "volume": "62", "number": "12", "publisher": "Wiley", "pagerange": "Art. No. e202216102", "id_number": "CaltechAUTHORS:20230307-207211000.41", "issn": "1433-7851", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230307-207211000.41", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0021266" }, { "agency": "Resnick Sustainability Institute" } ] }, "local_group": { "items": [ { "id": "Liquid-Sunlight-Alliance" }, { "id": "Resnick-Sustainability-Institute" } ] }, "doi": "10.1002/anie.202216102", "resource_type": "article", "pub_year": "2023", "author_list": "Nie, Weixuan; Heim, Gavin P.; et el." }, { "id": "https://authors.library.caltech.edu/records/y5bvr-n4t30", "eprint_id": 118283, "eprint_status": "archive", "datestamp": "2023-08-22 18:44:52", "lastmod": "2023-10-24 23:16:15", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Watkins-Nicholas-B", "name": { "family": "Watkins", "given": "Nicholas B." }, "orcid": "0000-0001-7251-9387" }, { "id": "Wu-Yueshen", "name": { "family": "Wu", "given": "Yueshen" }, "orcid": "0000-0002-3784-0594" }, { "id": "Nie-Weixuan", "name": { "family": "Nie", "given": "Weixuan" }, "orcid": "0000-0003-2094-6840" }, { "id": "Peters-J-C", "name": { "family": "Peters", "given": "Jonas C." }, "orcid": "0000-0002-6610-4414" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "In Situ Deposited Polyaromatic Layer Generates Robust Copper Catalyst for Selective Electrochemical CO\u2082 Reduction at Variable pH", "ispublished": "pub", "full_text_status": "public", "keywords": "Materials Chemistry; Energy Engineering and Power Technology; Fuel Technology; Renewable Energy, Sustainability and the Environment; Chemistry (miscellaneous)", "note": "Research was in part carried out at the Molecular Materials Research Center in the Beckman Institute; accordingly, we thank Bruce Brunschwig for the assistance with surface FT-IR measurements and Jake Evans for the assistance with XPS measurements. We also thank Aidan Fenwick for the assistance with AFM measurements and Matthias Richter for the assistance with XPS measurements. This material is based on work performed by the Liquid Sunlight Alliance, which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Fuels from Sunlight Hub under Award Number DE-SC0021266. The Resnick Sustainability Institute at Caltech is also acknowledged for its support of enabling infrastructure and facilities.", "abstract": "Electrochemical reduction of CO\u2082 (CO\u2082R) by Cu metal holds promise to convert CO\u2082 to valuable C\u2082\u208a chemicals at scale using electricity and water but suffers from poor selectivity. Coating of metal electrodes with small organic molecules or polymers has been shown to effectively enhance catalytic performance but remains underexplored. Herein, facile modification of Cu surfaces by a polyaromatic layer was found to boost both selectivity and activity toward C\u2082\u208a products. Using phenyldiazonium or diphenyliodonium salts to graft an organic layer onto the surface of Cu foil electrodes resulted in up to 75% Faradaic efficiency (FE) for C\u2082\u208a at neutral pH. Modified electrodes have electrochemical active surface areas and proton diffusion coefficients similar to those of bare Cu. High CO\u2082R performance was maintained in a gas diffusion electrode, with a pH \u2248 1 electrolyte (1 M H\u2083PO\u2084, 1 M KCl; \u2212100 mA/cm\u00b2), producing 65% FE for C\u2082\u208a over 5 h, with no delamination.", "date": "2023-01-13", "date_type": "published", "publication": "ACS Energy Letters", "volume": "8", "number": "1", "publisher": "American Chemical Society", "pagerange": "189-195", "id_number": "CaltechAUTHORS:20221209-478595000.6", "issn": "2380-8195", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20221209-478595000.6", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0021266" }, { "agency": "Resnick Sustainability Institute" } ] }, "local_group": { "items": [ { "id": "Liquid-Sunlight-Alliance" }, { "id": "Resnick-Sustainability-Institute" } ] }, "doi": "10.1021/acsenergylett.2c02002", "resource_type": "article", "pub_year": "2023", "author_list": "Watkins, Nicholas B.; Wu, Yueshen; et el." }, { "id": "https://authors.library.caltech.edu/records/0hmyh-2nr90", "eprint_id": 118947, "eprint_status": "archive", "datestamp": "2023-10-19 23:28:33", "lastmod": "2023-10-20 00:01:12", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Scott-Anna-G", "name": { "family": "Scott", "given": "Anna G." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Synthesis of a Fe\u2083-Carbyne Motif by Oxidation of an Alkyl Ligated Iron-Sulfur (WFe\u2083S\u2083) Cluster", "ispublished": "pub", "full_text_status": "public", "keywords": "Colloid and Surface Chemistry; Biochemistry; General Chemistry; Catalysis", "note": "We are grateful to the National Institutes of Health (R01-GM102687B to T.A.) and the National Science Foundation (Graduate Research Fellowships Program to A.G.S.) for funding. We thank the Beckman Institute and the Dow Next Generation Grant for instrumentation support. Michael Takase is thanked for assistance with crystallography. We are grateful to Paul Oyala for assistance with EPR experiments.", "abstract": "The presence of a carbide ligand in the active site of nitrogenases remains an unusual example of organometallic chemistry employed by a protein. Carbide incorporation into the MFe\u2087S\u2089 C cluster involves complex biosynthesis, but analogous synthetic methodologies are limited. Herein, we present a new synthetic strategy for incorporating carbon based bridging ligands into iron\u2013sulfur clusters. Starting from a halide precursor, a WFe\u2083S\u2083 cluster displaying three terminal alkyl ligands and an open Fe\u2083 face was prepared. Oxidation results in loss of alkane and formation of a \u03bc3-carbyne. Characterization of these clusters and mechanistic studies are presented.", "date": "2023-01-11", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "145", "number": "1", "publisher": "American Chemical Society", "pagerange": "2-6", "id_number": "CaltechAUTHORS:20230125-515005200.29", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230125-515005200.29", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687B" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "Caltech Beckman Institute" }, { "agency": "Dow Next Generation Educator Fund" } ] }, "doi": "10.1021/jacs.2c04826", "pmcid": "PMC10575540", "primary_object": { "basename": "nihms-1933068.pdf", "url": "https://authors.library.caltech.edu/records/0hmyh-2nr90/files/nihms-1933068.pdf" }, "related_objects": [ { "basename": "NIHMS1933068-supplement-ja2c04826_si_001.pdf", "url": "https://authors.library.caltech.edu/records/0hmyh-2nr90/files/NIHMS1933068-supplement-ja2c04826_si_001.pdf" } ], "resource_type": "article", "pub_year": "2023", "author_list": "Scott, Anna G. and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/zvt4e-63a35", "eprint_id": 115705, "eprint_status": "archive", "datestamp": "2023-08-22 17:17:46", "lastmod": "2023-10-24 16:41:19", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Shoshani-Manar-M", "name": { "family": "Shoshani", "given": "Manar M." }, "orcid": "0000-0002-4051-3367" }, { "id": "Xiong-Shuoyan", "name": { "family": "Xiong", "given": "Shuoyan" }, "orcid": "0000-0002-2579-4260" }, { "id": "Lawniczak-James-J", "name": { "family": "Lawniczak", "given": "James J." }, "orcid": "0000-0003-1898-9809" }, { "id": "Zhang-Xinglong", "name": { "family": "Zhang", "given": "Xinglong" }, "orcid": "0000-0003-1698-692X" }, { "id": "Miller-T-F-III", "name": { "family": "Miller", "given": "Thomas F., III" }, "orcid": "0000-0002-1882-5380" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Phosphine-Phenoxide Nickel Catalysts for Ethylene/Acrylate Copolymerization: Olefin Coordination and Complex Isomerization Studies Relevant to the Mechanism of Catalysis", "ispublished": "pub", "full_text_status": "public", "keywords": "Catalysts, Hydrocarbons, Ligands, Molecular structure, Organic compounds; Inorganic Chemistry; Organic Chemistry; Physical and Theoretical Chemistry", "note": "\u00a9 2022 American Chemical Society. \n\nPublished online 14 July 2022. \n\nWe are grateful to Dow (T.A.) and the Natural Sciences and Engineering Research Counsel of Canada (M.M.S.) for funding. X.Z. acknowledges the Agency for Science, Technology and Research (A*STAR), Singapore, for a National Science Scholarship. We thank Brad Bailey and Heather Spinney (Dow) for insightful discussions. We thank Michael Takase and Lawrence Henling for assistance with X-ray crystallography and David VanderVelde for assistance with NMR spectroscopy. We thank Alex Nett, Briana Henderson, and Hannah Bailey (Dow) for assistance in collecting polymer characterization data (GPC, DSC, and FT-IR). Support has been provided for the X-ray diffraction and NMR instrumentation via the Dow Next Generation Educator Fund. This work used the Bridges-2 system at the Pittsburgh Supercomputing Center (PSC). This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE--1144469. \n\nAuthor Contributions. M.M.S and S.X contributed equally. \n\nThe authors declare no competing financial interest. \n\nAccession Codes. CCDC 2173352\u20132173356 and 2173358 contain the supplementary crystallographic data for this paper.\n\nSupplemental Material - om2c00241_si_001.pdf
Supplemental Material - om2c00241_si_002.zip
", "abstract": "The insertion copolymerization of ethylene and acrylate remains a challenge in polymer synthesis due to decreased activities upon incorporation of the polar monomer. Toward gaining mechanistic insight, two elusive four-membered chelated intermediates generated after acrylate insertion were prepared (1-CCO and 2-CCO), and their ligand coordination and substitution behavior were studied. Specifically, an ethylene-coordinated species was characterized by NMR spectroscopy upon exposing 2-CCO to ethylene at low temperatures, a rare observation for neutral late-transition metal polymerization catalysts. Thermodynamics of chelate-opening and monomer coordination from 2-CCO were determined at \u221290 \u00b0C (\u0394G of 0.4 kcal/mol for ethylene and 1.9 kcal/mol for 1-hexene). The Gibbs energy barrier of ligand exchange from pyridine to ethylene, a prerequisite for ethylene insertion in catalysis, was determined to be 3.3 kcal/mol. Ligand-binding studies reveal that compared to NiMe and Ni(CH\u2082SiMe\u2083) complexes, acrylate inserted species 1L-CCO and 2L-CCO produce compressed thermodynamic binding scales for both electronically and sterically differentiating ligands, potentially related to their more electron-deficient nickel centers as suggested by computational studies. Triethylphosphine complexes 1P, 2P, and 2P\u2013Me were observed as both cis and trans isomers in solution. \u00b3\u00b9P{\u00b9H} EXSY NMR studies of 2P reveal conversion between a cis and trans isomers that does not involve exchange with free PEt\u2083, supporting the mechanism of intramolecular isomerization. 2-CCO, a neutral Ni(II) precatalyst that does not display an auxiliary ligand, serves as a highly active catalyst for copolymerization.", "date": "2022-08-08", "date_type": "published", "publication": "Organometallics", "volume": "41", "number": "15", "publisher": "American Chemical Society", "pagerange": "2119-2131", "id_number": "CaltechAUTHORS:20220720-918328000", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220720-918328000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Next Generation Educator Fund" }, { "agency": "Natural Sciences and Engineering Research Council of Canada (NSERC)" }, { "agency": "Agency for Science, Technology and Research (A*STAR)" }, { "agency": "NSF Graduate Research Fellowship", "grant_number": "DGE-1144469" } ] }, "doi": "10.1021/acs.organomet.2c00241", "primary_object": { "basename": "om2c00241_si_002.zip", "url": "https://authors.library.caltech.edu/records/zvt4e-63a35/files/om2c00241_si_002.zip" }, "related_objects": [ { "basename": "om2c00241_si_001.pdf", "url": "https://authors.library.caltech.edu/records/zvt4e-63a35/files/om2c00241_si_001.pdf" } ], "resource_type": "article", "pub_year": "2022", "author_list": "Shoshani, Manar M.; Xiong, Shuoyan; et el." }, { "id": "https://authors.library.caltech.edu/records/tjssa-mcb33", "eprint_id": 115697, "eprint_status": "archive", "datestamp": "2023-09-15 07:41:21", "lastmod": "2023-10-23 21:36:52", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xiong-Shuoyan", "name": { "family": "Xiong", "given": "Shuoyan" }, "orcid": "0000-0002-2579-4260" }, { "id": "Hong-Alexandria", "name": { "family": "Hong", "given": "Alexandria" } }, { "id": "Bailey-Brad-C", "name": { "family": "Bailey", "given": "Brad C." } }, { "id": "Spinney-Heather-A", "name": { "family": "Spinney", "given": "Heather A." } }, { "id": "Senecal-Todd-D", "name": { "family": "Senecal", "given": "Todd D." } }, { "id": "Bailey-Hannah", "name": { "family": "Bailey", "given": "Hannah" } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Highly Active and Thermally Robust Nickel Enolate Catalysts for the Synthesis of Ethylene\u2010Acrylate Copolymers", "ispublished": "pub", "full_text_status": "public", "keywords": "Acrylate; Catalysis; Copolymers; Nickel; Olefins; General Chemistry", "note": "\u00a9 2022 Wiley-VCH GmbH. \n\nVersion of Record online: 18 July 2022. Accepted manuscript online: 20 June 2022. Manuscript received: 06 May 2022. \n\nWe are grateful to Dow for funding (T.A.) and to the Caltech SURF program for a Ronan Armaan Mack fellowship (A.H.). We thank Jerzy Klosin, Alex Nett for insightful discussions. We thank Heidi Clements for GPC and tBA incorporation analysis. We thank Michael Takase for assistance with X-ray crystallography and David VanderVelde for assistance with NMR spectroscopy. Support has been provided for the X-ray diffraction and NMR instrumentation via the Dow Next Generation Educator Fund. S.X. acknowledge Manar Shoshani for assistance in refinement of solid-state structures and Yu Chen for assistance in generating topographical steric maps. \n\nData Availability Statement. The data that support the findings of this study are available in the Supporting Information of this article. \n\nThe authors declare no conflict of interest.\n\nAccepted Version - Angew_Chem_Int_Ed_-_2022_-_Xiong_-_Highly_Active_and_Thermally_Robust_Nickel_Enolate_Catalysts_for_the_Synthesis_of.pdf
", "abstract": "The insertion copolymerization of polar olefins and ethylene remains a significant challenge in part due to catalysts\u2032 low activity and poor thermal stability. Herein we demonstrate a strategy toward addressing these obstacles through ligand design. Neutral nickel phosphine enolate catalysts with large phosphine substituents reaching the axial positions of Ni achieve activity of up to 7.7\u00d710\u00b3\u2005kg\u2009mol\u207b\u00b9\u2009h\u207b\u00b9 (efficiency >35\u00d710\u00b3\u2005g copolymer/g Ni) at 110\u2009\u00b0C, notable for ethylene/acrylate copolymerization. NMR analysis of resulting copolymers reveals highly linear microstructures with main-chain ester functionality. Structure-performance studies indicate a strong correlation between axial steric hindrance and catalyst performance.", "date": "2022-07-22", "date_type": "published", "publication": "Angewandte Chemie International Edition", "publisher": "Wiley", "id_number": "CaltechAUTHORS:20220720-917478000", "issn": "1433-7851", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220720-917478000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech Summer Undergraduate Research Fellowship (SURF)" }, { "agency": "Dow Next Generation Educator Fund" } ] }, "doi": "10.1002/anie.202206637", "primary_object": { "basename": "Angew_Chem_Int_Ed_-_2022_-_Xiong_-_Highly_Active_and_Thermally_Robust_Nickel_Enolate_Catalysts_for_the_Synthesis_of.pdf", "url": "https://authors.library.caltech.edu/records/tjssa-mcb33/files/Angew_Chem_Int_Ed_-_2022_-_Xiong_-_Highly_Active_and_Thermally_Robust_Nickel_Enolate_Catalysts_for_the_Synthesis_of.pdf" }, "resource_type": "article", "pub_year": "2022", "author_list": "Xiong, Shuoyan; Hong, Alexandria; et el." }, { "id": "https://authors.library.caltech.edu/records/06n2q-96t82", "eprint_id": 115556, "eprint_status": "archive", "datestamp": "2023-08-22 16:52:44", "lastmod": "2023-10-24 16:35:00", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Shiau-Angela-A", "name": { "family": "Shiau", "given": "Angela A." }, "orcid": "0000-0003-4395-9847" }, { "id": "Lee-Heui-Beom", "name": { "family": "Lee", "given": "Heui Beom" }, "orcid": "0000-0002-9550-2649" }, { "id": "Oyala-Paul-H", "name": { "family": "Oyala", "given": "Paul H." }, "orcid": "0000-0002-8761-4667" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Mn\u1d35\u2c7d\u2084O\u2084 Model of the S\u2083 Intermediate of the Oxygen-Evolving Complex: Effect of the Dianionic Disiloxide Ligand", "ispublished": "pub", "full_text_status": "public", "keywords": "Cluster chemistry, Ligands, Quantum mechanics, Redox reactions, Transition metals; Inorganic Chemistry; Physical and Theoretical Chemistry", "note": "\u00a9 2022 American Chemical Society. \n\nPublished online 13 July 2022. \n\nThis article is part of the Discrete Coordination Cages and Metal Clusters special issue. \n\nThis research was supported by the NIH (Grant R01-GM102687B). We thank the Beckman Institute at Caltech and the Dow Next Generation Educator Fund for instrumentation support. Magnetic data were acquired on a SQUID supported by NSF Grant MRI-1625776. We thank Dr. Michael Takase and Lawrence Henling for assistance with X-ray crystallography and Dr. Ignacio Martini with SQUID magnetometry. \n\nThe authors declare no competing financial interest. \n\nAccession Codes. CCDC 2171723 and 2171724 contain the supplementary crystallographic data for this paper\n\nSupplemental Material - ic2c01612_si_001.pdf
", "abstract": "Synthetic complexes provide useful models to study the interplay between the structure and spectroscopy of the different Sn-state intermediates of the oxygen-evolving complex (OEC) of photosystem II (PSII). Complexes containing the Mn\u1d35\u2c7d\u2084 core corresponding to the S\u2083 state, the last observable intermediate prior to dioxygen formation, remain very rare. Toward the development of synthetic strategies to stabilize highly oxidized tetranuclear complexes, ligands with increased anion charge were pursued. Herein, we report the synthesis, electrochemistry, SQUID magnetometry, and electron paramagnetic resonance spectroscopy of a stable Mn\u1d35\u2c7d\u2084O\u2084 cuboidal complex supported by a disiloxide ligand. The substitution of an anionic acetate or amidate ligand with a dianionic disiloxide ligand shifts the reduction potential of the Mn\u1d35\u1d35\u1d35Mn\u1d35\u2c7d\u2083/Mn\u1d35\u2c7d\u2084 redox couple by up to \u223c760 mV, improving stability. The S = 3 spin ground state of the siloxide-ligated Mn\u1d35\u2c7d\u2084O\u2084 complex matches the acetate and amidate variants, in corroboration with the MnIV4 assignment of the S\u2083 state of the OEC.", "date": "2022-07-14", "date_type": "published", "publication": "Inorganic Chemistry", "publisher": "American Chemical Society", "id_number": "CaltechAUTHORS:20220714-369441000", "issn": "0020-1669", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220714-369441000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687B" }, { "agency": "Caltech Beckman Institute" }, { "agency": "Dow Next Generation Educator Fund" }, { "agency": "NSF", "grant_number": "CHE-1625776" } ] }, "doi": "10.1021/acs.inorgchem.2c01612", "primary_object": { "basename": "ic2c01612_si_001.pdf", "url": "https://authors.library.caltech.edu/records/06n2q-96t82/files/ic2c01612_si_001.pdf" }, "resource_type": "article", "pub_year": "2022", "author_list": "Shiau, Angela A.; Lee, Heui Beom; et el." }, { "id": "https://authors.library.caltech.edu/records/rwcvz-f2f09", "eprint_id": 114851, "eprint_status": "archive", "datestamp": "2023-08-22 15:42:09", "lastmod": "2023-10-24 15:13:33", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Low-Choon-Heng", "name": { "family": "Low", "given": "Choon Heng" }, "orcid": "0000-0002-9219-3377" }, { "id": "Buss-Joshua-A", "name": { "family": "Buss", "given": "Joshua A." }, "orcid": "0000-0002-3347-8583" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Molybdenum-Mediated Coupling of Carbon Monoxide to a C\u2083 Product on a Single Metal Site", "ispublished": "pub", "full_text_status": "public", "keywords": "Aromatic compounds, Hydrocarbons, Ligands ,Organophosphorus compounds, Reactivity; Inorganic Chemistry; Physical and Theoretical Chemistry", "note": "\u00a9 2022 American Chemical Society. \n\nReceived: January 24, 2022; Published: May 9, 2022. \n\nWe are grateful to the NSF (CHE-1800501 to T.A.; GRFP to J.A.B.) and the Agency of Science, Technology and Research (A*STAR), Singapore (C.H.L.) for funding. We thank Lawrence M. Henling and Michael K. Takase for crystallographic assistance and David VanderVelde for advice on NMR spectroscopy. The Dow Next Generation Educator Fund is thanked for instrument grants to Caltech. \n\nThe authors declare no competing financial interest. \n\nAccession Codes. CCDC 1495764, 1909081\u20131909084, and 2117715\u20132117716 contain the supplementary crystallographic data for this paper\n\nSupplemental Material - ic2c00266_si_001.pdf
", "abstract": "The synthesis and characterization of a series of naphthalenediyl-diphosphine molybdenum complexes are reported. A novel dicarbonyl\u2013Mo complex (3) converts to a bis(siloxy)acetylene complex (5) upon reduction and treatment with a silyl electrophile, Me\u2083SiCl. This process shows exclusive C\u2013C coupling distinct from the previously reported phenylene-linked analogue that undergoes C\u2013O cleavage. Further CO catenation can be engendered from 5 under mild conditions providing metallacyclobutenone complex 6, with a C\u2083O\u2083 organic motif derived from CO. Differences in reactivity are assigned to the nature of the arene linker, where the naphthalenediyl fragment shows a propensity for \u03b7\u2074 binding previously not observed for phenylene. Consistent with this hypothesis, a Mo precursor with a 1,3-cyclohexadienediyl-based linker was prepared which also showed exclusive formation of a bis(siloxy)acetylene complex and subsequent coupling of a third CO molecule.", "date": "2022-05-23", "date_type": "published", "publication": "Inorganic Chemistry", "volume": "61", "number": "20", "publisher": "American Chemical Society", "pagerange": "7710-7714", "id_number": "CaltechAUTHORS:20220520-231441000", "issn": "0020-1669", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220520-231441000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-1800501" }, { "agency": "Agency for Science, Technology and Research (A*STAR)" }, { "agency": "Dow Next Generation Educator Fund" } ] }, "doi": "10.1021/acs.inorgchem.2c00266", "primary_object": { "basename": "ic2c00266_si_001.pdf", "url": "https://authors.library.caltech.edu/records/rwcvz-f2f09/files/ic2c00266_si_001.pdf" }, "resource_type": "article", "pub_year": "2022", "author_list": "Low, Choon Heng; Buss, Joshua A.; et el." }, { "id": "https://authors.library.caltech.edu/records/zpda7-k2k63", "eprint_id": 114023, "eprint_status": "archive", "datestamp": "2023-08-22 15:07:16", "lastmod": "2023-10-23 20:02:56", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Barluzzi-Luciano", "name": { "family": "Barluzzi", "given": "Luciano" }, "orcid": "0000-0001-6682-342X" }, { "id": "Jori-Nadir", "name": { "family": "Jori", "given": "Nadir" }, "orcid": "0000-0002-9375-894X" }, { "id": "He-Tianyi", "name": { "family": "He", "given": "Tianyi" }, "orcid": "0000-0002-8191-188X" }, { "id": "Rajeshkumar-Thayalan", "name": { "family": "Rajeshkumar", "given": "Thayalan" } }, { "id": "Scopelliti-Rosario", "name": { "family": "Scopelliti", "given": "Rosario" }, "orcid": "0000-0001-8161-8715" }, { "id": "Maron-Laurent", "name": { "family": "Maron", "given": "Laurent" }, "orcid": "0000-0003-2653-8557" }, { "id": "Oyala-Paul-H", "name": { "family": "Oyala", "given": "Paul" }, "orcid": "0000-0002-8761-4667" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Mazzanti-Marinella", "name": { "family": "Mazzanti", "given": "Marinella" }, "orcid": "0000-0002-3427-008X" } ] }, "title": "Heterometallic uranium/molybdenum nitride synthesis via partial N-atom transfer", "ispublished": "pub", "full_text_status": "public", "keywords": "Materials Chemistry; Metals and Alloys; Surfaces, Coatings and Films; General Chemistry; Ceramics and Composites; Electronic, Optical and Magnetic Materials; Catalysis", "note": "\u00a9 The Royal Society of Chemistry 2022. \n\nSubmitted 24 Jan 2022. Accepted 10 Mar 2022. First published 10 Mar 2022. \n\nM. M. acknowledges financial support from the Swiss National Science Foundation (grant 178793) and the Ecole Polytechnique F\u00e9d\u00e9rale de Lausanne (EPFL) and thanks Dr A. Sienkiewicz for preliminary EPR data collection. T. A. is grateful to the NSF for financial support (CHE-1800501). L. M. is a senior member of the Institut Universitaire de France. CalMip is acknowledged for a generous grant of computing time. \n\nThere are no conflicts to declare.\n\nSupplemental Material - d2cc00473a1.pdf
Supplemental Material - d2cc00473a2.cif
", "abstract": "The reaction of a Mo(ii) terminal nitride with U(iii) generates the first example of a transition metal capped uranium nitride. The nitride is triply bonded to U(v) and singly bonded to Mo(0) with a U\u2013Mo interaction and reacts with CO to yield cyanate.", "date": "2022-04-14", "date_type": "published", "publication": "Chemical Communications", "volume": "58", "number": "29", "publisher": "Royal Society of Chemistry", "pagerange": "4655-4658", "id_number": "CaltechAUTHORS:20220323-704268000", "issn": "1359-7345", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220323-704268000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Swiss National Science Foundation (SNSF)", "grant_number": "178793" }, { "agency": "Ecole Polytechnique F\u00e9d\u00e9rale de Lausanne (EPFL)" }, { "agency": "NSF", "grant_number": "CHE-1800501" } ] }, "doi": "10.1039/d2cc00473a", "primary_object": { "basename": "d2cc00473a1.pdf", "url": "https://authors.library.caltech.edu/records/zpda7-k2k63/files/d2cc00473a1.pdf" }, "related_objects": [ { "basename": "d2cc00473a2.cif", "url": "https://authors.library.caltech.edu/records/zpda7-k2k63/files/d2cc00473a2.cif" } ], "resource_type": "article", "pub_year": "2022", "author_list": "Barluzzi, Luciano; Jori, Nadir; et el." }, { "id": "https://authors.library.caltech.edu/records/benpx-wj703", "eprint_id": 113672, "eprint_status": "archive", "datestamp": "2023-08-22 14:35:11", "lastmod": "2023-10-23 23:10:41", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lai-Yungchieh", "name": { "family": "Lai", "given": "Yungchieh" }, "orcid": "0000-0001-9392-1447" }, { "id": "Watkins-Nicholas-B", "name": { "family": "Watkins", "given": "Nicholas B." }, "orcid": "0000-0001-7251-9387" }, { "id": "Muzzillo-Christopher", "name": { "family": "Muzzillo", "given": "Christopher" }, "orcid": "0000-0002-6492-0098" }, { "id": "Richter-Matthias-H", "name": { "family": "Richter", "given": "Matthias" }, "orcid": "0000-0003-0091-2045" }, { "id": "Kan-Kevin-S", "name": { "family": "Kan", "given": "Kevin" } }, { "id": "Zhou-Lan", "name": { "family": "Zhou", "given": "Lan" }, "orcid": "0000-0002-7052-266X" }, { "id": "Haber-Joel-A", "name": { "family": "Haber", "given": "Joel A." }, "orcid": "0000-0001-7847-5506" }, { "id": "Zakutayev-Andriy", "name": { "family": "Zakutayev", "given": "Andriy" }, "orcid": "0000-0002-3054-5525" }, { "id": "Peters-J-C", "name": { "family": "Peters", "given": "Jonas C." }, "orcid": "0000-0002-6610-4414" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Gregoire-J-M", "name": { "family": "Gregoire", "given": "John M." }, "orcid": "0000-0002-2863-5265" } ] }, "title": "Molecular Coatings Improve the Selectivity and Durability of CO\u2082 Reduction Chalcogenide Photocathodes", "ispublished": "pub", "full_text_status": "public", "keywords": "Coating materials, Additives, Photonics, Cadmium sulfide, Electrodes; Materials Chemistry; Energy Engineering and Power Technology; Fuel Technology; Renewable Energy, Sustainability and the Environment; Chemistry (miscellaneous)", "note": "\u00a9 2022 American Chemical Society. \n\nReceived 18 December 2021. Accepted 23 February 2022. Published online 1 March 2022. \n\nThis material is based on work performed by the Liquid Sunlight Alliance, which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Fuels from Sunlight Hub under Award Number DE-SC0021266. National Renewable Energy Laboratory is operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. The Resnick Sustainability Institute at Caltech is also acknowledged for its support of enabling infrastructure and facilities. \n\nThe views expressed in this article do not necessarily represent the views of the DOE or the U.S. Government. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - nz1c02762_si_001.pdf
", "abstract": "The quest for solar-driven conversion of carbon dioxide to chemicals and fuels hinges upon the identification of an efficient, durable, and selective photocathode. Chalcogenide p-type semiconductors exemplified by chalcopyrite Cu(In,Ga)Se\u2082 (CIGS) have been effectively deployed as photocathodes. However, selectivity toward CO\u2082 reduction and durability of the commonly used CdS adlayer remain primary challenges. Here, we demonstrate that for the wide band gap CuGa\u2083Se\u2085 chalcopyrite absorber these challenges are well addressed by an organic coating generated in situ from an N,N\u2032-(1,4-phenylene)bispyridinium ditriflate salt in the electrolyte. The molecular additive provides a 30-fold increase in selectivity toward CO\u2082R products compared to the unmodified system and lowers Cd corrosion at least 10-fold. This dual functionality highlights the promise of hybrid solid-state-molecular photocathodes for enabling durable and efficient solar fuel systems.", "date": "2022-03-11", "date_type": "published", "publication": "ACS Energy Letters", "volume": "7", "number": "3", "publisher": "American Chemical Society", "pagerange": "1195-1201", "id_number": "CaltechAUTHORS:20220301-900116000", "issn": "2380-8195", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220301-900116000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0021266" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC36-08GO28308" }, { "agency": "Resnick Sustainability Institute" } ] }, "local_group": { "items": [ { "id": "Resnick-Sustainability-Institute" }, { "id": "Liquid-Sunlight-Alliance" } ] }, "doi": "10.1021/acsenergylett.1c02762", "primary_object": { "basename": "nz1c02762_si_001.pdf", "url": "https://authors.library.caltech.edu/records/benpx-wj703/files/nz1c02762_si_001.pdf" }, "resource_type": "article", "pub_year": "2022", "author_list": "Lai, Yungchieh; Watkins, Nicholas B.; et el." }, { "id": "https://authors.library.caltech.edu/records/4mcqw-kak78", "eprint_id": 112130, "eprint_status": "archive", "datestamp": "2023-08-22 12:51:38", "lastmod": "2023-10-23 20:55:04", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Arnett-Charles-H", "name": { "family": "Arnett", "given": "Charles H." }, "orcid": "0000-0002-1272-3797" }, { "id": "Oyala-Paul-H", "name": { "family": "Oyala", "given": "Paul H." }, "orcid": "0000-0002-8761-4667" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Probing Redox Non-Innocence in Iron\u2013Carbene Complexes {Fe=C(H)Ar}\u00b9\u2070\u207b\u00b9\u00b9 by ^(1,2)H and \u00b9\u00b3C Pulse Electron Paramagnetic Resonance", "ispublished": "pub", "full_text_status": "public", "keywords": "metal\u2013carbene; open-shell complexes; organometallics; pulse EPR; redox non-innocence; General Chemistry; Catalysis", "note": "\u00a9 2021 Wiley-VCH GmbH. \n\nIssue Online: 13 December 2021; Version of Record online: 10 November 2021; Accepted manuscript online: 25 October 2021; Manuscript received: 09 August 2021. \n \nWe are grateful to the NSF for funding (CHE-1905320 to T.A. and an NSF Graduate Research Fellowship to C.H.A.). We thank Prof. Jonas Peters for the use of his group's M\u00f6ssbauer spectrometer. We thank Michael Takase and Lawrence Henling for assistance with X-ray crystallography and David VanderVelde for assistance with NMR spectroscopy. Support has been provided for the Caltech EPR Facility via an NSF grant (1531940) and the Dow Next Generation Educator Fund, which is also acknowledged for support of the X-ray diffraction and NMR instrumentation. The computations presented here were conducted on the Caltech High Performance Cluster partially supported by a grant from the Gordon and Betty Moore Foundation. \n\nThe authors declare no conflict of interest.\n\nAccepted Version - anie.202110704.pdf
Supplemental Material - anie202110704-sup-0001-misc_information.pdf
", "abstract": "We report the synthesis and spectroscopic characterization of a series of iron-carbene complexes in redox states {Fe=C(H)Ar}\u00b9\u2070\u207b\u00b9\u00b9. Pulse EPR studies of the ^(1,2)H and \u00b9\u00b3C isotopologues of {Fe=C(H)Ar}\u00b9\u00b9 reveal the high covalency of the Fe\u2013carbene bonding, leading to a more even spin distribution than commonly observed for reduced Fischer carbenes.", "date": "2021-12-20", "date_type": "published", "publication": "Angewandte Chemie International Edition", "volume": "60", "number": "52", "publisher": "Wiley", "pagerange": "27220-27224", "id_number": "CaltechAUTHORS:20211201-162456410", "issn": "1433-7851", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20211201-162456410", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-1905320" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "NSF", "grant_number": "CHE-1531940" }, { "agency": "Dow Next Generation Educator Fund" }, { "agency": "Gordon and Betty Moore Foundation" } ] }, "doi": "10.1002/anie.202110704", "primary_object": { "basename": "anie202110704-sup-0001-misc_information.pdf", "url": "https://authors.library.caltech.edu/records/4mcqw-kak78/files/anie202110704-sup-0001-misc_information.pdf" }, "related_objects": [ { "basename": "anie.202110704.pdf", "url": "https://authors.library.caltech.edu/records/4mcqw-kak78/files/anie.202110704.pdf" } ], "resource_type": "article", "pub_year": "2021", "author_list": "Arnett, Charles H.; Oyala, Paul H.; et el." }, { "id": "https://authors.library.caltech.edu/records/0bgxb-bzt64", "eprint_id": 112195, "eprint_status": "archive", "datestamp": "2023-08-22 12:43:47", "lastmod": "2023-10-23 17:47:50", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Le-Linh-N-V", "name": { "family": "Le", "given": "Linh N. V." }, "orcid": "0000-0003-1451-2675" }, { "id": "Bailey-Gwendolyn-A", "name": { "family": "Bailey", "given": "Gwendolyn A." }, "orcid": "0000-0002-6636-4128" }, { "id": "Scott-Anna-G", "name": { "family": "Scott", "given": "Anna G." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Partial synthetic models of FeMoco with sulfide and carbyne ligands: Effect of interstitial atom in nitrogenase active site", "ispublished": "pub", "full_text_status": "public", "keywords": "FeMoco model; nitrogenase; carbide clusters; reduction potential; iron-sulfur clusters; Multidisciplinary", "note": "\u00a9 2021 National Academy of Sciences. Published under the PNAS license. \n\nEdited by Marcetta Y. Darensbourg, Texas A&M University, College Station, TX, and approved October 26, 2021 (received for review May 20, 2021). \n\nWe are grateful to the NIH (R01-GM102687B to T.A.), Natural Sciences and Engineering Research Council of Canada (G.A.B.), the Resnick Sustainability Institute at Caltech (G.A.B.), and the NSF (Graduate Research Fellowships Program to A.G.S.) for funding. We thank the Beckman Institute and the Dow Next Generation Grant for instrumentation support. Michael Takase, Lawrence Henling, and Manar Shoshani are thanked for assistance with crystallography. \n\nData Availability: Atomic coordinates and structure factors data have been deposited in the Cambridge Structural Database (CSD) of the Cambridge Crystallographic Data Centre (https://www.ccdc.cam.ac.uk/structures/). CSD reference numbers are as follows: 2084246 (1-Mo), 2081620 (2-W), 2084269 (2-Mo), 2081619 (3), 2081616 (4-W), 2084247 (4-Mo), 2081621 (5), 2081617 (6), 2081622 (7), and 2084054 (8). All other study data are included in the article and/or SI Appendix. \n\nAuthor contributions: L.N.V.L., G.A.B., A.G.S., and T.A. designed research; L.N.V.L., G.A.B., and A.G.S. performed research; L.N.V.L., G.A.B., A.G.S., and T.A. analyzed data; L.N.V.L., G.A.B., A.G.S., and T.A. wrote the paper; and T.A. mentored researchers. \n\nThe authors declare no competing interest. \n\nThis article is a PNAS Direct Submission. \n\nThis article contains supporting information online at https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2109241118/-/DCSupplemental.\n\nPublished - e2109241118.full.pdf
Supplemental Material - pnas.2109241118.sapp.pdf
", "abstract": "Nitrogen-fixing organisms perform dinitrogen reduction to ammonia at an Fe-M (M = Mo, Fe, or V) cofactor (FeMco) of nitrogenase. FeMco displays eight metal centers bridged by sulfides and a carbide having the MFe\u2087S\u2088C cluster composition. The role of the carbide ligand, a unique motif in protein active sites, remains poorly understood. Toward addressing how the carbon bridge affects the physical and chemical properties of the cluster, we isolated synthetic models of subsite MFe\u2083S\u2083C displaying sulfides and a chelating carbyne ligand. We developed synthetic protocols for structurally related clusters, [Tp*M'Fe\u2083S\u2083X]^(n\u2212), where M' = Mo or W, the bridging ligand X = CR, N, NR, S, and Tp* = Tris(3,5-dimethyl-1-pyrazolyl)hydroborate, to study the effects of the identity of the heterometal and the bridging X group on structure and electrochemistry. While the nature of M' results in minor changes, the chelating, \u03bc\u2083-bridging carbyne has a large impact on reduction potentials, being up to 1 V more reducing compared to nonchelating N and S analogs.", "date": "2021-12-07", "date_type": "published", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "volume": "118", "number": "49", "publisher": "National Academy of Sciences", "pagerange": "Art. No. e2109241118", "id_number": "CaltechAUTHORS:20211203-175255320", "issn": "0027-8424", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20211203-175255320", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687B" }, { "agency": "Natural Sciences and Engineering Research Council of Canada (NSERC)" }, { "agency": "Resnick Sustainability Institute" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "Caltech Beckman Institute" }, { "agency": "Dow Next Generation Educator Fund" } ] }, "local_group": { "items": [ { "id": "Resnick-Sustainability-Institute" } ] }, "doi": "10.1073/pnas.2109241118", "pmcid": "PMC8670491", "primary_object": { "basename": "e2109241118.full.pdf", "url": "https://authors.library.caltech.edu/records/0bgxb-bzt64/files/e2109241118.full.pdf" }, "related_objects": [ { "basename": "pnas.2109241118.sapp.pdf", "url": "https://authors.library.caltech.edu/records/0bgxb-bzt64/files/pnas.2109241118.sapp.pdf" } ], "resource_type": "article", "pub_year": "2021", "author_list": "Le, Linh N. V.; Bailey, Gwendolyn A.; et el." }, { "id": "https://authors.library.caltech.edu/records/79x9a-6tg63", "eprint_id": 111694, "eprint_status": "archive", "datestamp": "2023-08-20 05:54:26", "lastmod": "2023-10-23 20:41:30", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Buss-Joshua-A", "name": { "family": "Buss", "given": "Joshua A." }, "orcid": "0000-0002-3347-8583" }, { "id": "Shida-Naoki", "name": { "family": "Shida", "given": "Naoki" }, "orcid": "0000-0003-0586-1216" }, { "id": "He-Tianyi", "name": { "family": "He", "given": "Tianyi" }, "orcid": "0000-0002-8191-188X" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Carbon Dioxide Reduction with Dihydrogen and Silanes at Low-Valent Molybdenum Terphenyl Diphosphine Complexes: Reductant Identity Dictates Mechanism", "ispublished": "pub", "full_text_status": "public", "keywords": "CO2 reduction, hydrogen storage, formic acid dehydrogenation, hydrosilylation, molybdenum", "note": "\u00a9 2021 American Chemical Society. \n\nReceived: June 29, 2021; Revised: September 8, 2021. \n\nThe authors thank Larry Henling and Mike Takase for crystallographic assistance and David VanderVelde for NMR expertise. The X-ray diffraction and NMR instrumentation were partially supported by the Dow Next Generation Educator Fund. T.A. is grateful for support from the NSF (CHE-1800501) for synthetic studies and DOE (Joint Center for Artificial Photosynthesis, Award Number DE-SC0004993) and King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia (offered under the KFUPM-Caltech Research Collaboration) for CO\u2082 conversion studies. J.A.B. and N.S. are grateful for an NSF graduate research fellowship and a Grant-in-Aid for JSPS Research Fellows (No. 16J07350), respectively. \n\nAuthor Contributions: J.A.B. and N.S. contributed equally to this work. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - cs1c02922_si_001.cif
Supplemental Material - cs1c02922_si_002.pdf
", "abstract": "The reaction chemistry of both silanes and hydrogen at para-terphenyl diphosphine-supported molybdenum complexes was explored within the context of carbon dioxide (CO\u2082) reduction. CO\u2082 hydrosilylation commonly affords reduction products via silyl acetals. However, while silyl hydride complexes were characterized in the present system, synthetic, spectroscopic, and kinetic studies suggest C\u2013O cleavage of CO\u2082 occurs independently of silanes. In their presence, a putative molybdenum oxo intermediate is hypothesized to undergo O-atom transfer, yielding silanol. In contrast, hydrogenation chemistry does occur through an intermediate molybdenum dihydride capable of inserting CO\u2082 to yield a formate hydride complex. This process is reversible; slow deinsertion under dinitrogen affords a mixture of molybdenum dihydride, \u03b7\u00b2-CO\u2082, and N\u2082 complexes. The molybdenum hydride formate species is a competent precatalyst for both CO\u2082 hydrogenation to formate (in the presence of lithium cations and base) and formic acid dehydrogenation to CO\u2082 and hydrogen (in the presence of base). Mechanistic studies of both catalytic processes are presented.", "date": "2021-11-05", "date_type": "published", "publication": "ACS Catalysis", "volume": "11", "number": "21", "publisher": "American Chemical Society", "pagerange": "13294-13302", "id_number": "CaltechAUTHORS:20211029-221513000", "issn": "2155-5435", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20211029-221513000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Next Generation Educator Fund" }, { "agency": "NSF", "grant_number": "CHE-1800501" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0004993" }, { "agency": "King Fahd University of Petroleum and Minerals (KFUPM)" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "Japan Society for the Promotion of Science (JSPS)", "grant_number": "16J07350" } ] }, "doi": "10.1021/acscatal.1c02922", "primary_object": { "basename": "cs1c02922_si_001.cif", "url": "https://authors.library.caltech.edu/records/79x9a-6tg63/files/cs1c02922_si_001.cif" }, "related_objects": [ { "basename": "cs1c02922_si_002.pdf", "url": "https://authors.library.caltech.edu/records/79x9a-6tg63/files/cs1c02922_si_002.pdf" } ], "resource_type": "article", "pub_year": "2021", "author_list": "Buss, Joshua A.; Shida, Naoki; et el." }, { "id": "https://authors.library.caltech.edu/records/sahhv-ks850", "eprint_id": 109461, "eprint_status": "archive", "datestamp": "2023-08-20 05:43:49", "lastmod": "2023-10-23 15:33:30", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lai-Yunchieh", "name": { "family": "Lai", "given": "Yunchieh" } }, { "id": "Watkins-Nicholas-B", "name": { "family": "Watkins", "given": "Nicholas B." }, "orcid": "0000-0001-7251-9387" }, { "id": "Rosas-Hern\u00e1ndez-Alonso", "name": { "family": "Rosas-Hern\u00e1ndez", "given": "Alonso" }, "orcid": "0000-0002-0812-5591" }, { "id": "Thevenon-Arnaud", "name": { "family": "Thevenon", "given": "Arnaud" }, "orcid": "0000-0002-5543-6595" }, { "id": "Heim-Gavin-P", "name": { "family": "Heim", "given": "Gavin P." }, "orcid": "0000-0002-9244-6565" }, { "id": "Zhou-Lan", "name": { "family": "Zhou", "given": "Lan" }, "orcid": "0000-0002-7052-266X" }, { "id": "Wu-Yueshen", "name": { "family": "Wu", "given": "Yueshen" }, "orcid": "0000-0002-3784-0594" }, { "id": "Peters-J-C", "name": { "family": "Peters", "given": "Jonas C." }, "orcid": "0000-0002-6610-4414" }, { "id": "Gregoire-J-M", "name": { "family": "Gregoire", "given": "John M." }, "orcid": "0000-0002-2863-5265" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Breaking Scaling Relationships in CO\u2082 Reduction on Copper Alloys with Organic Additives", "ispublished": "pub", "full_text_status": "public", "keywords": "Additives, Alloys, Electrical properties, Catalysts, Selectivity", "note": "\u00a9 2021 The Authors. Published by American Chemical Society. Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) \n\nReceived: July 16, 2021; Published: October 14, 2021. \n\nThis material is based on work performed by the Liquid Sunlight Alliance, which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Fuels from Sunlight Hub under Award DE-SC0021266. A.T. acknowledges Marie Sk\u0142odowska-Curie Fellowship H2020-MSCA-IF-2017 (793471). The Resnick Sustainability Institute at Caltech is acknowledged for support of the laboratory facilities in which this research was conducted. \n\nAuthor Contributions: Y.L. and N.B.W. contributed equally to this work. \n\nThe authors declare no competing financial interest.\n\nPublished - acscentsci.1c00860.pdf
Submitted - Breaking_Scaling_Relationships_in_CO2_Reduction_on_Copper_Alloys_with_Organic_Additives_v1.pdf
Supplemental Material - oc1c00860_si_001.pdf
", "abstract": "Boundary conditions for catalyst performance in the conversion of common precursors such as N\u2082, O\u2082, H\u2082O, and CO\u2082 are governed by linear free energy and scaling relationships. Knowledge of these limits offers an impetus for designing strategies to alter reaction mechanisms to improve performance. Typically, experimental demonstrations of linear trends and deviations from them are composed of a small number of data points constrained by inherent experimental limitations. Herein, high-throughput experimentation on 14 bulk copper bimetallic alloys allowed for data-driven identification of a scaling relationship between the partial current densities of methane and C\u2082\u208a products. This strict dependence represents an intrinsic limit to the Faradaic efficiency for C\u2013C coupling. We have furthermore demonstrated that coating the electrodes with a molecular film breaks the scaling relationship to promote C\u2082\u208a product formation.", "date": "2021-10-27", "date_type": "published", "publication": "ACS Central Science", "volume": "7", "number": "10", "publisher": "American Chemical Society", "pagerange": "1756-1762", "id_number": "CaltechAUTHORS:20210610-080047277", "issn": "2374-7951", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210610-080047277", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0021266" }, { "agency": "Marie Curie Fellowship", "grant_number": "793471" }, { "agency": "Resnick Sustainability Institute" } ] }, "local_group": { "items": [ { "id": "Resnick-Sustainability-Institute" }, { "id": "Liquid-Sunlight-Alliance" } ] }, "doi": "10.1021/acscentsci.1c00860", "pmcid": "PMC8554824", "primary_object": { "basename": "acscentsci.1c00860.pdf", "url": "https://authors.library.caltech.edu/records/sahhv-ks850/files/acscentsci.1c00860.pdf" }, "related_objects": [ { "basename": "oc1c00860_si_001.pdf", "url": "https://authors.library.caltech.edu/records/sahhv-ks850/files/oc1c00860_si_001.pdf" }, { "basename": "Breaking_Scaling_Relationships_in_CO2_Reduction_on_Copper_Alloys_with_Organic_Additives_v1.pdf", "url": "https://authors.library.caltech.edu/records/sahhv-ks850/files/Breaking_Scaling_Relationships_in_CO2_Reduction_on_Copper_Alloys_with_Organic_Additives_v1.pdf" } ], "resource_type": "article", "pub_year": "2021", "author_list": "Lai, Yunchieh; Watkins, Nicholas B.; et el." }, { "id": "https://authors.library.caltech.edu/records/ms7mx-66z24", "eprint_id": 110953, "eprint_status": "archive", "datestamp": "2023-08-20 05:32:50", "lastmod": "2023-10-23 19:57:16", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Yadegari-Hossein", "name": { "family": "Yadegari", "given": "Hossein" }, "orcid": "0000-0002-2572-182X" }, { "id": "Ozden-Adnan", "name": { "family": "Ozden", "given": "Adnan" }, "orcid": "0000-0002-6924-1967" }, { "id": "Alkayyali-Tartela", "name": { "family": "Alkayyali", "given": "Tartela" }, "orcid": "0000-0003-3895-8700" }, { "id": "Soni-Vikram", "name": { "family": "Soni", "given": "Vikram" }, "orcid": "0000-0001-9354-475X" }, { "id": "Thevenon-Arnaud", "name": { "family": "Thevenon", "given": "Arnaud" }, "orcid": "0000-0002-5543-6595" }, { "id": "Rosas-Hern\u00e1ndez-Alonso", "name": { "family": "Rosas-Hern\u00e1ndez", "given": "Alonso" }, "orcid": "0000-0002-0812-5591" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Peters-J-C", "name": { "family": "Peters", "given": "Jonas C." }, "orcid": "0000-0002-6610-4414" }, { "id": "Sargent-Edward-H", "name": { "family": "Sargent", "given": "Edward H." }, "orcid": "0000-0003-0396-6495" }, { "id": "Sinton-David", "name": { "family": "Sinton", "given": "David" }, "orcid": "0000-0003-2714-6408" } ] }, "title": "Glycerol Oxidation Pairs with Carbon Monoxide Reduction for Low-Voltage Generation of C\u2082 and C\u2083 Product Streams", "ispublished": "pub", "full_text_status": "public", "keywords": "Oxides, Alcohols, Electrodes, Inorganic carbon compounds, Electrical energy", "note": "\u00a9 2021 American Chemical Society. \n\nReceived: August 4, 2021; Published: September 14, 2021. \n\nThe authors acknowledge Ontario Centre for the Characterization of Advanced Materials (OCCAM) for sample preparation and characterization facilities. The authors acknowledge financial support from the Ontario Research Foundation: Research Excellence Program; the Natural Sciences and Engineering Research Council (NSERC) of Canada; the CIFAR Bio-Inspired Solar Energy program; and the Joint Centre of Artificial Synthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the US Department of Energy under Award No. DE-SC0004993. D.S. acknowledges the NSERC E.W.R Steacie Memorial Fellowship. A.T. acknowledges Marie Sk\u0142odowska-Curie Fellowship H2020-MSCA-IF-2017 (793471). Infrastructure support from the Canada Foundation for Innovation and the Ontario Research Fund are also gratefully acknowledged. \n\nAuthor Contributions: D.S. and E.S. supervised the project. H.Y., D.S., and A.O. conceived the idea and designed the experiments. H.Y. carried out the experiments, collected and analyzed the data, and wrote the manuscript. A.O. aided with electrochemical measurements and analytical characterizations. T.A. performed the COMSOL modeling. All authors discussed the results and contributed to manuscript editing. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - nz1c01639_si_001.pdf
", "abstract": "Electrochemical carbon dioxide reduction to multicarbon products provides the storage of renewable energy in the form of chemical bonds, as well as a means to displace fossil sources of chemical feedstocks. However, the accompanying anodic oxygen evolution reaction (OER) reduces the energy efficiency of the process without providing a salable product. Replacing OER with alternative organic oxidation reactions (OORs) is an emerging strategy to reduce the full-cell potential and generate valuable products on both sides of the cell. We pursue carbon monoxide reduction that avoids carbonate formation and benefits from highly alkaline anode conditions favorable for OOR. This coelectrolysis strategy achieves a cathodic C\u2082\u208a product stream (71% FE) and an anodic C\u2083 product stream (75% FE) at 180 mA cm\u207b\u00b2 with a full-cell potential of 1.34 V. The integrated system reduces the CO-to-C\u2082H\u2084 energy requirement by 55% (to \u223c72 GJ/ton_(C\u2082H\u2084)), halving the projected energy cost of ethylene production from CO\u2082.", "date": "2021-10-08", "date_type": "published", "publication": "ACS Energy Letters", "volume": "6", "number": "10", "publisher": "American Chemical Society", "pagerange": "3538-3544", "id_number": "CaltechAUTHORS:20210917-215618208", "issn": "2380-8195", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210917-215618208", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Ontario Research Foundation" }, { "agency": "Natural Sciences and Engineering Research Council of Canada (NSERC)" }, { "agency": "Canadian Institute for Advanced Research (CIFAR)" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0004993" }, { "agency": "Marie Curie Fellowship", "grant_number": "793471" }, { "agency": "Canada Foundation for Innovation" }, { "agency": "Ontario Research Fund" } ] }, "local_group": { "items": [ { "id": "JCAP" } ] }, "doi": "10.1021/acsenergylett.1c01639", "primary_object": { "basename": "nz1c01639_si_001.pdf", "url": "https://authors.library.caltech.edu/records/ms7mx-66z24/files/nz1c01639_si_001.pdf" }, "resource_type": "article", "pub_year": "2021", "author_list": "Yadegari, Hossein; Ozden, Adnan; et el." }, { "id": "https://authors.library.caltech.edu/records/q9rjh-5yb85", "eprint_id": 110641, "eprint_status": "archive", "datestamp": "2023-08-20 04:48:01", "lastmod": "2023-10-23 19:46:24", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Bailey-Gwendolyn-A", "name": { "family": "Bailey", "given": "Gwendolyn A." }, "orcid": "0000-0002-6636-4128" }, { "id": "Buss-Joshua-A", "name": { "family": "Buss", "given": "Joshua A." }, "orcid": "0000-0002-3347-8583" }, { "id": "Oyala-Paul-H", "name": { "family": "Oyala", "given": "Paul H." }, "orcid": "0000-0002-8761-4667" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Terminal, Open-Shell Mo Carbide and Carbyne Complexes: Spin Delocalization and Ligand Noninnocence", "ispublished": "pub", "full_text_status": "public", "keywords": "Ligands, Delocalization, Inorganic carbon compounds, Quantum mechanics, Energy levels", "note": "\u00a9 2021 American Chemical Society. \n\nReceived 11 April 2021. Published online 11 August 2021. Published in issue 25 August 2021. \n\nWe thank Lawrence Henling, Michael Takase, and Manar Shoshani for invaluable crystallographic assistance. Lawrence Henling is also thanked for assistance with elemental analysis. G.A.B. is grateful to NSERC of Canada and the Resnick Sustainability Institute at Caltech for fellowship support. J.A.B. is grateful for an NSF graduate research fellowship. We thank the NSF (CHE-1800501), the Dow Next Generation Education Fund (instrumentation), and Caltech for funding. \n\nThe authors declare no competing financial interest. \n\nAccession Codes. CCDC 2076055, 2076057\u20132076058, and 2076060 contain the supplementary crystallographic data for this paper.\n\nSupplemental Material - ja1c03806_si_001.pdf
", "abstract": "Open-shell compounds bearing metal\u2013carbon triple bonds, such as carbides and carbynes, are of significant interest as plausible intermediates in the reductive catenation of C\u2081 oxygenates. Despite the abundance of closed-shell carbynes reported, open-shell variants are very limited, and an open-shell carbide has yet to be reported. Herein, we report the synthesis of the first terminal, open-shell carbide complexes, [K][1] and [1][BAr^F\u2084] (1 = P2Mo(\u2261C:)(CO), P2 = a terphenyl diphosphine ligand), which differ by two redox states, as well as a series of related open-shell carbyne complexes. The complexes are characterized by single-crystal X-ray diffraction and NMR, EPR, and IR spectroscopies, while the electronic structures are probed by EPR studies and DFT calculations to assess spin delocalization. In the d\u2081 complexes, the spin is primarily localized on the metal (\u223c55\u201377% Mo d_(xy)) with delocalization on the triply bonded carbon of \u223c0.05\u20130.09 e\u207b. In the reduced carbide [K][1], a direct metal\u2013arene interaction enables ancillary ligand reduction, resulting in reduced radical character on the terminal carbide (\u2a7d0.02 e\u207b). Reactivity studies with [K][1] reveal the formation of mixed-valent C\u2013C coupled products at \u221240 \u00b0C, illustrating how productive reactivity manifolds can be engendered through the manipulation of redox states. Combined, the results inform on the electronic structure and reactivity of a new and underrepresented class of compounds with potential significance to a wide array of reactions involving open-shell species.", "date": "2021-08-25", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "143", "number": "33", "publisher": "American Chemical Society", "pagerange": "13091-13102", "id_number": "CaltechAUTHORS:20210831-200226268", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210831-200226268", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Natural Sciences and Engineering Research Council of Canada (NSERC)" }, { "agency": "Resnick Sustainability Institute" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "NSF", "grant_number": "CHE-1800501" }, { "agency": "Dow Next Generation Education Fund" }, { "agency": "Caltech" } ] }, "local_group": { "items": [ { "id": "Resnick-Sustainability-Institute" } ] }, "doi": "10.1021/jacs.1c03806", "primary_object": { "basename": "ja1c03806_si_001.pdf", "url": "https://authors.library.caltech.edu/records/q9rjh-5yb85/files/ja1c03806_si_001.pdf" }, "resource_type": "article", "pub_year": "2021", "author_list": "Bailey, Gwendolyn A.; Buss, Joshua A.; et el." }, { "id": "https://authors.library.caltech.edu/records/2vdej-70453", "eprint_id": 110627, "eprint_status": "archive", "datestamp": "2023-08-20 04:46:41", "lastmod": "2023-10-23 19:45:48", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Bailey-Gwendolyn-A", "name": { "family": "Bailey", "given": "Gwendolyn A." }, "orcid": "0000-0002-6636-4128" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Terminal Mo Carbide and Carbyne Reactivity: H\u2082 Cleavage, B\u2013C Bond Activation, and C\u2013C Coupling", "ispublished": "pub", "full_text_status": "public", "keywords": "Carbene compounds, Ligands, Chemical reactions, Inorganic carbon compounds, Reactivity", "note": "\u00a9 2021 American Chemical Society. \n\nReceived 6 June 2021. Published online 12 August 2021. Published in issue 23 August 2021. \n\nWe thank Lawrence Henling and Michael Takase for invaluable crystallographic assistance. G.A.B. is grateful to the NSERC of Canada and the Resnick Sustainability Institute at Caltech for fellowship support. We thank the the NSF (CHE-1800501), the Dow Next Generation Education Fund (instrumentation), and Caltech for funding. \n\nThe authors declare no competing financial interest. \n\nCCDC 2000078\u20132000079 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif.\n\nSupplemental Material - om1c00336_si_001.xyz
Supplemental Material - om1c00336_si_002.pdf
", "abstract": "Transition-metal carbides have been posited as intermediates in the upgrading of C\u2081 feedstocks, including the Fischer\u2013Tropsch synthesis of higher olefins from CO and H\u2082. Still, molecular examples remain rare, and their reactivity is poorly understood. In a molecular platform supported by a flexible terphenyl diphosphine ligand, the important C\u2013C coupling step was previously demonstrated on the reaction of Mo carbide and carbene species with CO. Methylidyne and methylidene complexes were accessible on sequential treatment of the carbide with sources of H\u207a and H\u207b, surrogates for heterolyzed H\u2082. Herein, we demonstrate that the terminal carbide complex is also capable of directly activating H\u2082, yielding a P\u2013C-bonded ylide complex. The carbide moiety also inserts into the B\u2013C bond of triphenylborane, yielding an unusual example of a borylcarbene with a direct Mo\u2013B contact. C\u2013C coupling from the terminal methylidyne, a potential intermediate formed on heterolytic H\u2082 cleavage and H\u207a transfer to the carbide, yields a Mo ketenyl complex, thus giving information for the first time on the relative rates of coupling from carbide, carbyne, and carbene species in the same molecular platform.", "date": "2021-08-23", "date_type": "published", "publication": "Organometallics", "volume": "40", "number": "16", "publisher": "American Chemical Society", "pagerange": "2881-2887", "id_number": "CaltechAUTHORS:20210830-230028871", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210830-230028871", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Natural Sciences and Engineering Research Council of Canada (NSERC)" }, { "agency": "Resnick Sustainability Institute" }, { "agency": "NSF", "grant_number": "CHE-1800501" }, { "agency": "Dow Next Generation Educator Fund" }, { "agency": "Caltech" } ] }, "local_group": { "items": [ { "id": "Resnick-Sustainability-Institute" } ] }, "doi": "10.1021/acs.organomet.1c00336", "primary_object": { "basename": "om1c00336_si_001.xyz", "url": "https://authors.library.caltech.edu/records/2vdej-70453/files/om1c00336_si_001.xyz" }, "related_objects": [ { "basename": "om1c00336_si_002.pdf", "url": "https://authors.library.caltech.edu/records/2vdej-70453/files/om1c00336_si_002.pdf" } ], "resource_type": "article", "pub_year": "2021", "author_list": "Bailey, Gwendolyn A. and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/xxmcb-70q98", "eprint_id": 109270, "eprint_status": "archive", "datestamp": "2023-08-22 10:47:00", "lastmod": "2023-10-23 17:47:11", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lee-Heui-Beom", "name": { "family": "Lee", "given": "Heui Beom" }, "orcid": "0000-0002-9550-2649" }, { "id": "Shiau-Angela-A", "name": { "family": "Shiau", "given": "Angela A." }, "orcid": "0000-0003-4395-9847" }, { "id": "Marchiori-David-A", "name": { "family": "Marchiori", "given": "David A." }, "orcid": "0000-0001-9738-3674" }, { "id": "Oyala-Paul-H", "name": { "family": "Oyala", "given": "Paul H." }, "orcid": "0000-0002-8761-4667" }, { "id": "Yoo-Byung-Kuk", "name": { "family": "Yoo", "given": "Byung-Kuk" }, "orcid": "0000-0002-2610-6685" }, { "id": "Kaiser-Jens-T", "name": { "family": "Kaiser", "given": "Jens T." }, "orcid": "0000-0002-5948-5212" }, { "id": "Rees-D-C", "name": { "family": "Rees", "given": "Douglas C." }, "orcid": "0000-0003-4073-1185" }, { "id": "Britt-R-David", "name": { "family": "Britt", "given": "R. David" }, "orcid": "0000-0003-0889-8436" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "CaMn\u2083^(IV)O\u2084 Cubane Models of the Oxygen Evolving Complex: Spin Ground States S < 9/2 and the Effect of Oxo Protonation", "ispublished": "pub", "full_text_status": "public", "keywords": "electronic structure; magnetic susceptibility; model complexes; oxygen-evolving complex; spin states", "note": "\u00a9 2021 Wiley-VCH GmbH. \n\nIssue Online: 26 July 2021; Version of Record online: 01 July 2021; Accepted manuscript online: 26 May 2021; Manuscript received: 25 April 2021. \n\nThis research was supported by the NIH (R01-GM102687B to T.A.), Dow Next Generation Educator (instrumentation), NSF-1531940 (Caltech EPR facility), the Division of Chemical Sciences, Geosciences, and Biosciences (R.D.B. grant DE-SC0007203) of the Office of Basic Energy Sciences of the U.S. Department of Energy. We thank Dr. Michael\u2005K. Takase and Mr. Lawrence M. Henling at Caltech for assistance with XRD; Dr. Ignacio B. Martini at UCLA for assistance with magnetometry (NSF, MRI-1625776). We thank Andrey Malyutin and Songye Chen for their support during the microED data collection conducted at the Caltech cryoEM facility, and the Beckman Institute at Caltech for their generous support of the cryoEM facility and the Molecular Observatory. \n\nThe authors declare no conflict of interest.\n\nAccepted Version - nihms-1709882.pdf
Supplemental Material - anie202105303-sup-0001-misc_information.pdf
", "abstract": "We report the single crystal XRD and MicroED structure, magnetic susceptibility, and EPR data of a series of CaMn\u2083^(IV)O\u2084 and YMn\u2083^(IV)O\u2084 complexes as structural and spectroscopic models of the cuboidal subunit of the oxygen-evolving complex (OEC). The effect of changes in heterometal identity, cluster geometry, and bridging oxo protonation on the spin-state structure was investigated. In contrast to previous computational models, we show that the spin ground state of CaMn\u2083^(IV)O\u2084 complexes and variants with protonated oxo moieties need not be S = 9/2. Desymmetrization of the pseudo-C\u2083-symmetric Ca(Y)Mn\u2083^(IV)O\u2084 core leads to a lower S = 5/2 spin ground state. The magnitude of the magnetic exchange coupling is attenuated upon oxo protonation, and an S = 3/2 spin ground state is observed in CaMn\u2083^(IV)O\u2083(OH). Our studies complement the observation that the interconversion between the low-spin and high-spin forms of the S\u2082 state is pH-dependent, suggesting that the (de)protonation of bridging or terminal oxygen atoms in the OEC may be connected to spin-state changes.", "date": "2021-08-02", "date_type": "published", "publication": "Angewandte Chemie International Edition", "volume": "60", "number": "32", "publisher": "Wiley", "pagerange": "17671-17679", "id_number": "CaltechAUTHORS:20210527-093456375", "issn": "1433-7851", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210527-093456375", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687B" }, { "agency": "Dow Next Generation Educator Fund" }, { "agency": "NSF", "grant_number": "CHE-1531940" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0007203" }, { "agency": "NSF", "grant_number": "CHE-1625776" } ] }, "doi": "10.1002/anie.202105303", "pmcid": "PMC8319083", "primary_object": { "basename": "anie202105303-sup-0001-misc_information.pdf", "url": "https://authors.library.caltech.edu/records/xxmcb-70q98/files/anie202105303-sup-0001-misc_information.pdf" }, "related_objects": [ { "basename": "nihms-1709882.pdf", "url": "https://authors.library.caltech.edu/records/xxmcb-70q98/files/nihms-1709882.pdf" } ], "resource_type": "article", "pub_year": "2021", "author_list": "Lee, Heui Beom; Shiau, Angela A.; et el." }, { "id": "https://authors.library.caltech.edu/records/evfpg-zv143", "eprint_id": 109548, "eprint_status": "archive", "datestamp": "2023-08-20 03:51:14", "lastmod": "2023-10-23 18:02:21", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Sampson-Jessica", "name": { "family": "Sampson", "given": "Jessica" } }, { "id": "Bruening-Meaghan", "name": { "family": "Bruening", "given": "Meaghan" } }, { "id": "Akhtar-Muhammed-Naseem", "name": { "family": "Akhtar", "given": "Muhammed Naseem" } }, { "id": "Jaseer-E-A", "name": { "family": "Jaseer", "given": "E. A." }, "orcid": "0000-0002-5385-8778" }, { "id": "Theravalappil-Rajesh", "name": { "family": "Theravalappil", "given": "Rajesh" } }, { "id": "Garcia-Nestor", "name": { "family": "Garcia", "given": "Nestor" } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Copolymerization of Ethylene and Long-Chain Functional \u03b1-Olefins by Dinuclear Zirconium Catalysts", "ispublished": "pub", "full_text_status": "public", "keywords": "Catalysts, Hydrocarbons, Bimetals, Metals, Copolymerization", "note": "\u00a9 2021 American Chemical Society. \n\nReceived: March 2, 2021; Published: June 7, 2021. \n\nThe authors are grateful for the support provided by the King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia, offered under the KFUPM-Caltech Research Collaboration. The authors are also grateful for the assistance of Dr. Dave VanderVelde in acquiring polymer NMR data. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - om1c00126_si_001.pdf
", "abstract": "Bimetallic catalysts have shown promise for improving polar comonomer incorporation by late transition metals, but such effects are underexplored using early transition metal catalysts. Herein, the copolymerization of ethylene and \u03b1-olefins bearing alcohol groups was performed using mono- and dizirconium bisamine bisphenolate catalysts in the presence of MAO and Al^iBu\u2083. Under these conditions, catalyst activity was retained with comonomer incorporation trends mirroring those observed with unfunctionalized \u03b1-olefins, i.e., lower incorporation by bimetallic catalysts. Although incorporation levels are low, these data provide mechanistic insight for polar comonomer incorporation. These results are consistent with our earlier proposal that larger comonomers sterically clash with the distal metal center of the bimetallic catalysts, leading to lower incorporation. Additionally, a bimetallic mechanism for polar comonomer coordination and incorporation is not supported by the current data.", "date": "2021-06-28", "date_type": "published", "publication": "Organometallics", "volume": "40", "number": "12", "publisher": "American Chemical Society", "pagerange": "1854-1858", "id_number": "CaltechAUTHORS:20210623-151211923", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210623-151211923", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "King Fahd University of Petroleum and Minerals (KFUPM)" } ] }, "doi": "10.1021/acs.organomet.1c00126", "primary_object": { "basename": "om1c00126_si_001.pdf", "url": "https://authors.library.caltech.edu/records/evfpg-zv143/files/om1c00126_si_001.pdf" }, "resource_type": "article", "pub_year": "2021", "author_list": "Sampson, Jessica; Bruening, Meaghan; et el." }, { "id": "https://authors.library.caltech.edu/records/8b09g-mqt75", "eprint_id": 108902, "eprint_status": "archive", "datestamp": "2023-08-20 03:10:28", "lastmod": "2023-10-23 17:24:46", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xiong-Shuoyan", "name": { "family": "Xiong", "given": "Shuoyan" } }, { "id": "Shoshani-Manar-M", "name": { "family": "Shoshani", "given": "Manar M." }, "orcid": "0000-0002-4051-3367" }, { "id": "Zhang-Xinglong", "name": { "family": "Zhang", "given": "Xinglong" }, "orcid": "0000-0003-1698-692X" }, { "id": "Spinney-Heather-A", "name": { "family": "Spinney", "given": "Heather A." } }, { "id": "Nett-Alex-J", "name": { "family": "Nett", "given": "Alex J." } }, { "id": "Henderson-Briana-S", "name": { "family": "Henderson", "given": "Briana S." } }, { "id": "Miller-T-F-III", "name": { "family": "Miller", "given": "Thomas F., III" }, "orcid": "0000-0002-1882-5380" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Efficient Copolymerization of Acrylate and Ethylene with Neutral P, O-Chelated Nickel Catalysts: Mechanistic Investigations of Monomer Insertion and Chelate Formation", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2021 American Chemical Society. \n\nReceived: January 20, 2021; Published: April 22, 2021. \n\nWe are grateful to Dow (TA) and the Natural Sciences and Engineering Research Counsel of Canada (MMS) for funding. We thank Brad Bailey and Jerzy Klosin (Dow) for insightful discussions. X.Z. acknowledges the Agency for Science, Technology and Research (A*STAR), Singapore, for a National Science Scholarship. We thank Michael Takase and Lawrence Henling for assistance with X-ray crystallography and David VanderVelde for assistance with NMR spectroscopy. We thank Heidi Clements, Hannah Bailey, and Joshua Castleman (Dow) for assistance in collecting polymer characterization data (GPC, DSC, FT-IR). We thank Todd Senecal and Steve Marshall (Dow) for assistance in collecting batch reactor data. Support has been provided for the X-ray diffraction and NMR instrumentation via the Dow Next Generation Educator Fund. X.Z. and T.F.M. acknowledge the computational resources from the Extreme Science and Engineering Discovery Environment (XSEDE) Bridges computer at the Pittsburgh Supercomputing Center through allocation TG-MCB160013. \n\nAuthor Contributions: S.X., M.M.S., and X.Z. contributed equally. \n\nThe authors declare the following competing financial interest(s): A patent application including ligand 1 was filed.\n\nSupplemental Material - ja1c00566_si_001.zip
Supplemental Material - ja1c00566_si_002.pdf
", "abstract": "The efficient copolymerization of acrylates with ethylene using Ni catalysts remains a challenge. Herein, we report two neutral Ni(II) catalysts (POP-Ni-py (1) and PONap-Ni-py (2)) that exhibit high thermal stability and significantly higher incorporation of polar monomer (for 1) or improved resistance to tert-butylacrylate (tBA)-induced chain transfer (for 2), in comparison to previously reported catalysts. Nickel alkyl complexes generated after tBA insertion, POP-Ni-CCO(py) (3) and PONap-Ni-CCO(py) (4), were isolated and, for the first time, characterized by crystallography. Weakened lutidine vs pyridine coordination in 2-lut facilitated the isolation of a N-donor-free adduct after acrylate insertion PONap-Ni-CCO (5) which represents a novel example of a four-membered chelate relevant to acrylate polymerization catalysis. Experimental kinetic studies of six cases of monomer insertion with aforementioned nickel complexes indicate that pyridine dissociation and monomer coordination are fast relative to monomer migratory insertion and that monomer enchainment after tBA insertion is the rate limiting step of copolymerization. Further evaluation of monomer insertion using density functional theory studies identified a cis\u2013trans isomerization via Berry-pseudorotation involving one of the pendant ether groups as the rate-limiting step for propagation, in the absence of a polar group at the chain end. The energy profiles for ethylene and tBA enchainments are in qualitative agreement with experimental measurements.", "date": "2021-05-05", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "143", "number": "17", "publisher": "American Chemical Society", "pagerange": "6516-6527", "id_number": "CaltechAUTHORS:20210430-120931834", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210430-120931834", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" }, { "agency": "Natural Sciences and Engineering Research Council of Canada (NSERC)" }, { "agency": "Agency for Science, Technology and Research (A*STAR)" }, { "agency": "Dow Next Generation Educator Fund" }, { "agency": "NSF", "grant_number": "TG-MCB160013" } ] }, "doi": "10.1021/jacs.1c00566", "primary_object": { "basename": "ja1c00566_si_001.zip", "url": "https://authors.library.caltech.edu/records/8b09g-mqt75/files/ja1c00566_si_001.zip" }, "related_objects": [ { "basename": "ja1c00566_si_002.pdf", "url": "https://authors.library.caltech.edu/records/8b09g-mqt75/files/ja1c00566_si_002.pdf" } ], "resource_type": "article", "pub_year": "2021", "author_list": "Xiong, Shuoyan; Shoshani, Manar M.; et el." }, { "id": "https://authors.library.caltech.edu/records/0p5xg-31620", "eprint_id": 108586, "eprint_status": "archive", "datestamp": "2023-10-03 22:41:14", "lastmod": "2023-10-24 15:32:09", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Thevenon-Arnaud", "name": { "family": "Thevenon", "given": "Arnaud" }, "orcid": "0000-0002-5543-6595" }, { "id": "Rosas-Hern\u00e1ndez-Alonso", "name": { "family": "Rosas-Hern\u00e1ndez", "given": "Alonso" }, "orcid": "0000-0002-0812-5591" }, { "id": "Fontani-Herreros-Alex-M", "name": { "family": "Fontani-Herreros", "given": "Alex M." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Peters-J-C", "name": { "family": "Peters", "given": "Jonas C." }, "orcid": "0000-0002-6610-4414" } ] }, "title": "Dramatic HER Suppression on Ag Electrodes via Molecular Films for Highly Selective CO\u2082 to CO Reduction", "ispublished": "pub", "full_text_status": "public", "keywords": "electrocatalysis, CO\u2082RR, HER, solar fuels, modified electrodes, silver electrodes", "note": "\u00a9 2021 American Chemical Society. \n\nReceived: January 24, 2021; Revised: March 13, 2021; Published: March 29, 2021. \n\nNMR, AFM, and XPS, SEM, and EDX measurements were collected at the NMR Facility (Division of Chemistry and Chemical Engineering), the Molecular Materials Research Center (Beckman Institute), and the Analytic Facilities (Division of Geological and Planetary Sciences) of the California Institute of Technology, respectively. This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under award number DE-SC0004993. A.T. acknowledges Marie Sk\u0142odowska-Curie Fellowship H2020-MSCA-IF-2017 (793471). J.C.P also acknowledges additional support from the Resnick Sustainability Institute at Caltech.\n\nThe authors declare no competing financial interest.\n\nAccepted Version - ACS_Catalysis_Ag_additives.pdf
Supplemental Material - cs1c00338_si_001.pdf
", "abstract": "The carbon dioxide reduction reaction (CO\u2082RR) in aqueous electrolytes suffers from efficiency loss due to the competitive hydrogen evolution reaction (HER). Developing efficient methods to suppress HER is a crucial step toward CO\u2082 utilization. Herein we report the selective conversion of CO\u2082 to CO on planar silver electrodes with Faradaic efficiencies >99% using simple pyridinium-based additives. Similar to our previous studies on copper electrodes, the additives form an organic film which alters CO\u2082RR selectivity. We report electrochemical kinetic and other mechanistic data to shed light on the role of these organic layers in suppressing HER. These data suggest that hydrogen production is selectively inhibited by the growth of a hydrophobic organic layer on the silver surface that limits proton but not CO\u2082 mass transport at certain applied potentials. The data also point to the involvement of a proton-transfer within the rate-determining step of the catalysis, instead of the commonly observed electron-transfer step for the case of planar Ag electrodes.", "date": "2021-04-16", "date_type": "published", "publication": "ACS Catalysis", "volume": "11", "number": "8", "publisher": "American Chemical Society", "pagerange": "4530-4537", "id_number": "CaltechAUTHORS:20210330-144253307", "issn": "2155-5435", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210330-144253307", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0004993" }, { "agency": "Marie Curie Fellowship", "grant_number": "793471" }, { "agency": "Resnick Sustainability Institute" } ] }, "local_group": { "items": [ { "id": "JCAP" }, { "id": "Resnick-Sustainability-Institute" } ] }, "doi": "10.1021/acscatal.1c00338", "primary_object": { "basename": "ACS_Catalysis_Ag_additives.pdf", "url": "https://authors.library.caltech.edu/records/0p5xg-31620/files/ACS_Catalysis_Ag_additives.pdf" }, "related_objects": [ { "basename": "cs1c00338_si_001.pdf", "url": "https://authors.library.caltech.edu/records/0p5xg-31620/files/cs1c00338_si_001.pdf" } ], "resource_type": "article", "pub_year": "2021", "author_list": "Thevenon, Arnaud; Rosas-Hern\u00e1ndez, Alonso; et el." }, { "id": "https://authors.library.caltech.edu/records/vvx94-7ry60", "eprint_id": 108073, "eprint_status": "archive", "datestamp": "2023-10-03 22:36:51", "lastmod": "2023-10-24 15:31:30", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ozden-Adnan", "name": { "family": "Ozden", "given": "Adnan" }, "orcid": "0000-0002-6924-1967" }, { "id": "Wang-Yuhang", "name": { "family": "Wang", "given": "Yuhang" }, "orcid": "0000-0001-5336-5183" }, { "id": "Li-Fengwang", "name": { "family": "Li", "given": "Fengwang" }, "orcid": "0000-0003-1531-2966" }, { "id": "Luo-Mingchuan", "name": { "family": "Luo", "given": "Mingchuan" } }, { "id": "Sisler-Jared", "name": { "family": "Sisler", "given": "Jared" } }, { "id": "Thevenon-Arnaud", "name": { "family": "Thevenon", "given": "Arnaud" }, "orcid": "0000-0002-5543-6595" }, { "id": "Rosas-Hern\u00e1ndez-Alonso", "name": { "family": "Rosas-Hern\u00e1ndez", "given": "Alonso" }, "orcid": "0000-0002-0812-5591" }, { "id": "Burdyny-Thomas", "name": { "family": "Burdyny", "given": "Thomas" } }, { "id": "Lum-Yanwei", "name": { "family": "Lum", "given": "Yanwei" } }, { "id": "Yadegari-Hossein", "name": { "family": "Yadegari", "given": "Hossein" } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Peters-J-C", "name": { "family": "Peters", "given": "Jonas C." }, "orcid": "0000-0002-6610-4414" }, { "id": "Sargent-Edward-H", "name": { "family": "Sargent", "given": "Edward H." }, "orcid": "0000-0003-0396-6495" }, { "id": "Sinton-David", "name": { "family": "Sinton", "given": "David" }, "orcid": "0000-0003-2714-6408" } ] }, "title": "Cascade CO\u2082 electroreduction enables efficient carbonate-free production of ethylene", "ispublished": "pub", "full_text_status": "public", "keywords": "CO electroreduction; carbon utilization; ethylene electrolysis; electrolyser; membrane electrode assembly; solid-oxide electrolyser; catalyst design; molecular catalyst; energy efficiency", "note": "\u00a9 2021 Elsevier. \n\nReceived 19 October 2020, Revised 1 December 2020, Accepted 21 January 2021, Available online 15 February 2021. \n\nThe authors acknowledge Ontario Centre for the Characterization of Advanced Materials (OCCAM) for sample preparation and characterization facilities. Funding: this work received financial support from the Ontario Research Foundation: Research Excellence Program, the Natural Sciences and Engineering Research Council (NSERC) of Canada, the CIFAR Bio-Inspired Solar Energy program and TOTAL S.E. and the Joint Centre of Artificial Synthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the US Department of Energy under award no. DE-SC0004993. D.S. acknowledges the NSERC E.W.R Steacie Memorial Fellowship. A.T. acknowledges Marie Sk\u0142odowska-Curie Fellowship H2020-MSCA-IF-2017 (793471). The authors thank Dr. Y.-F. Liao for the GIWAXS measurements at Spring-8 BL-12B2 beamline of NSRRC. The authors also thank Dr. T. Regier for their assistance at the SGM beamline of CLS. \n\nAuthor contributions. D.S. and E.H.S. supervised the project. A.O. carried out all the electrochemical experiments with advice from Y.W. and F.L. A.T., A.R.-H., J.C.P., and T.A. designed and synthesized the N-tolylpyridinium molecule and contributed to the manuscript editing. A.O. and F.L. carried out Raman spectroscopies. Y.W. performed the SEM and TEM analysis. A.O. performed the nuclear magnetic resonance spectroscopies. A.O. and Y.W. co-wrote the manuscript. J.S. performed the TEA modeling. T.B. conducted the CO diffusion modeling. M.L., Y.L., and H.Y. contributed to the discussions and manuscript editing. A.O., Y.W., and F.L. provided equal contributions to this study. All authors contributed to the manuscript. \n\nDeclaration of interests. A.O., Y.W., F.L., D.S., and E.H.S. have filled provisional patent application no. 63/135,277 regarding Cascade CO2 electroreduction systems.\n\nSubmitted - Manuscript-Joule.docx
Supplemental Material - 1-s20-S2542435121000386-mmc1.pdf
", "abstract": "CO\u2082 electroreduction provides a route to convert waste emissions into chemicals such as ethylene (C\u2082H\u2084). However, the direct transformation of CO\u2082-to-C\u2082H\u2084 suffers from CO\u2082 loss to carbonate, consuming up to 72% of energy input. A cascade approach\u2014coupling a solid-oxide CO\u2082-to-CO electrochemical cell (SOEC) with a CO-to-C\u2082H\u2084 membrane electrode assembly (MEA)\u2014would eliminate CO\u2082 loss to carbonate. However, this approach requires a CO-to-C\u2082H\u2084 MEA with energy efficiency well beyond demonstrations to date. Focusing on the MEA, we find that an N-tolyl substituted tetrahydro-bipyridine film improves the stabilization of key reaction intermediates, while an SSC ionomer enhances CO transport to the Cu surface, enabling a C\u2082H\u2084 faradaic efficiency of 65% at 150 mA cm\u207b\u00b2 for 110 h. Demonstrating a cascade SOEC-MEA approach, we achieve CO\u2082-to-C\u2082H\u2084 with a ~48% reduction in energy intensity compared with the direct route. We further reduce the energy intensity by coupling CO electroreduction (CORR) with glucose electrooxidation.", "date": "2021-03-17", "date_type": "published", "publication": "Joule", "volume": "5", "number": "3", "publisher": "Cell Press", "pagerange": "706-719", "id_number": "CaltechAUTHORS:20210216-140504601", "issn": "2542-4351", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210216-140504601", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Ontario Research Foundation" }, { "agency": "Natural Sciences and Engineering Research Council of Canada (NSERC)" }, { "agency": "Canadian Institute for Advanced Research (CIFAR)" }, { "agency": "TOTAL" }, { "agency": "Joint Center for Artificial Photosynthesis (JCAP)" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0004993" }, { "agency": "Marie Curie Fellowship", "grant_number": "793471" } ] }, "local_group": { "items": [ { "id": "JCAP" } ] }, "doi": "10.1016/j.joule.2021.01.007", "primary_object": { "basename": "Manuscript-Joule.docx", "url": "https://authors.library.caltech.edu/records/vvx94-7ry60/files/Manuscript-Joule.docx" }, "related_objects": [ { "basename": "1-s20-S2542435121000386-mmc1.pdf", "url": "https://authors.library.caltech.edu/records/vvx94-7ry60/files/1-s20-S2542435121000386-mmc1.pdf" } ], "resource_type": "article", "pub_year": "2021", "author_list": "Ozden, Adnan; Wang, Yuhang; et el." }, { "id": "https://authors.library.caltech.edu/records/2qrdb-75657", "eprint_id": 106853, "eprint_status": "archive", "datestamp": "2023-08-20 01:09:00", "lastmod": "2023-10-23 15:07:02", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Hirscher-Nathanael-A", "name": { "family": "Hirscher", "given": "Nathanael A." } }, { "id": "Arnett-Charles-H", "name": { "family": "Arnett", "given": "Charles H." }, "orcid": "0000-0002-1272-3797" }, { "id": "Oyala-Paul-H", "name": { "family": "Oyala", "given": "Paul H." }, "orcid": "0000-0002-8761-4667" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Characterization of Cr-Hydrocarbyl Species via Pulse EPR in the Study of Ethylene Tetramerization Catalysis", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2020 American Chemical Society. \n\nReceived: July 31, 2020; Published: November 25, 2020. \n\nWe are grateful to The Dow Chemical Company, NSF-1531940 (EPR facility) and The Dow Next Generation Educator (instrumentation) for funding. We thank Dr. Sean Ewart for insightful discussions and Cooper Citek, Dirk Schild, and Gautam Stroscio for assistance with DFT calculations. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - om0c00521_si_001.pdf
Supplemental Material - om0c00521_si_002.xyz
", "abstract": "The characterization of complexes involved in chromium catalysis is challenging due to the paramagnetism of Cr in its common oxidation states. Here, we demonstrate the utility of pulse electron paramagnetic resonance (pulse EPR) techniques in assigning structural features of Cr organometallic complexes relevant to ethylene tetramerization. An S = 3/2, Cr(III) bisaryl-methyl ethylene tetramerization precatalyst (1) has been selected for characterization by CW and pulse EPR spectroscopies. Using an isotopically labeled Cr-CD\u2083 complex (1-d\u2083), the methyl ligand was confirmed to remain bound to Cr in solution by detection of \u00b2H couplings in X-band hyperfine sublevel correlation (HYSCORE) spectroscopy. Protonolysis of 1-d\u2083 led to an S = 3/2, Cr(III) product (2-d\u2083) that maintained spectroscopic features in HYSCORE for the CD\u2083 group, indicative of retention of the Cr-alkyl bond. Following protonolysis of 1-h\u2083 and subsequent reaction with ethylene, an S = 1/2 Cr(I) species with an ethylene-derived ligand was generated, supporting a mechanism involving this Cr oxidation state. Additionally, the pulse EPR characterization of a Cr(I) allyl-diene complex was performed for comparison. This is the first direct observation of hydrocarbyl ligands on Cr using pulse EPR methods. The methods described here are broadly applicable to Cr, first-row transition metals and other open-shell organometallic catalytic systems.", "date": "2020-12-28", "date_type": "published", "publication": "Organometallics", "volume": "39", "number": "24", "publisher": "American Chemical Society", "pagerange": "4420-4429", "id_number": "CaltechAUTHORS:20201201-075016332", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20201201-075016332", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" }, { "agency": "NSF", "grant_number": "CHE-1531940" }, { "agency": "Dow Next Generation Educator Fund" } ] }, "doi": "10.1021/acs.organomet.0c00521", "primary_object": { "basename": "om0c00521_si_002.xyz", "url": "https://authors.library.caltech.edu/records/2qrdb-75657/files/om0c00521_si_002.xyz" }, "related_objects": [ { "basename": "om0c00521_si_001.pdf", "url": "https://authors.library.caltech.edu/records/2qrdb-75657/files/om0c00521_si_001.pdf" } ], "resource_type": "article", "pub_year": "2020", "author_list": "Hirscher, Nathanael A.; Arnett, Charles H.; et el." }, { "id": "https://authors.library.caltech.edu/records/9t53z-44f43", "eprint_id": 104604, "eprint_status": "archive", "datestamp": "2023-08-20 00:27:31", "lastmod": "2023-10-20 22:59:22", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ribson-Ryan-D", "name": { "family": "Ribson", "given": "Ryan D." } }, { "id": "Choi-Gyeongshin", "name": { "family": "Choi", "given": "Gyeongshin" } }, { "id": "Hadt-R-G", "name": { "family": "Hadt", "given": "Ryan G." }, "orcid": "0000-0001-6026-1358" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Controlling Singlet Fission with Coordination Chemistry-Induced Assembly of Dipyridyl Pyrrole Bipentacenes", "ispublished": "pub", "full_text_status": "public", "keywords": "Nuclear fission, Hydrocarbons, Absorption, Fluorescence, Aromatic compounds", "note": "\u00a9 2020 American Chemical Society. This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. \n\nReceived: August 5, 2020; Published: November 10, 2020. \n\nThe authors thank Dr. Jay Winkler for assistance with time-resolved luminescence measurements, the Beckman Institute Laser Resource Center (BILRC) for access to the associated equipment, and Dr. David VanderVelde for NMR support and helpful discussions. Mike Takase and Larry Henling are acknowledged for crystallographic assistance. T.A. is grateful for the support provided by King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia, offered under the KFUPM-Caltech Research Collaboration and the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award DE-SC0004993. Financial support from Caltech and the Dow Next Generation Educator Fund is gratefully acknowledged (R.G.H.). \n\nThe authors declare no competing financial interest.\n\nPublished - acscentsci.0c01044.pdf
Supplemental Material - oc0c01044_si_001.pdf
", "abstract": "Singlet fission has the potential to surpass current efficiency limits in next-generation photovoltaics and to find use in quantum information science. Despite the demonstration of singlet fission in various materials, there is still a great need for fundamental design principles that allow for tuning of photophysical parameters, including the rate of fission and triplet lifetimes. Here, we describe the synthesis and photophysical characterization of a novel bipentacene dipyridyl pyrrole (HDPP-Pent) and its Li- and K-coordinated derivatives. HDPP-Pent undergoes singlet fission at roughly 50% efficiency (\u03c4_(SF) = 730 ps), whereas coordination in the Li complex induces significant structural changes to generate a dimer, resulting in a 7-fold rate increase (\u03c4_(SF) = 100 ps) and more efficient singlet fission with virtually no sacrifice in triplet lifetime. We thus illustrate novel design principles to produce favorable singlet fission properties, wherein through-space control can be achieved via coordination chemistry-induced multipentacene assembly.", "date": "2020-11-25", "date_type": "published", "publication": "ACS Central Science", "volume": "6", "number": "11", "publisher": "American Chemical Society", "pagerange": "2088-2096", "id_number": "CaltechAUTHORS:20200728-104820571", "issn": "2374-7943", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200728-104820571", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "King Fahd University of Petroleum and Minerals (KFUPM)" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0004993" }, { "agency": "Caltech" }, { "agency": "Dow Next Generation Educator Fund" } ] }, "local_group": { "items": [ { "id": "JCAP" } ] }, "doi": "10.1021/acscentsci.0c01044", "pmcid": "PMC7706079", "primary_object": { "basename": "Controlling_Singlet_Fission_with_Coordination_Chemistry-Induced_Assembly_of_Dipyridyl_Pyrrole_Bipentacenes_v1.pdf", "url": "https://authors.library.caltech.edu/records/9t53z-44f43/files/Controlling_Singlet_Fission_with_Coordination_Chemistry-Induced_Assembly_of_Dipyridyl_Pyrrole_Bipentacenes_v1.pdf" }, "related_objects": [ { "basename": "acscentsci.0c01044.pdf", "url": "https://authors.library.caltech.edu/records/9t53z-44f43/files/acscentsci.0c01044.pdf" }, { "basename": "oc0c01044_si_001.pdf", "url": "https://authors.library.caltech.edu/records/9t53z-44f43/files/oc0c01044_si_001.pdf" } ], "resource_type": "article", "pub_year": "2020", "author_list": "Ribson, Ryan D.; Choi, Gyeongshin; et el." }, { "id": "https://authors.library.caltech.edu/records/4njs4-k3188", "eprint_id": 105582, "eprint_status": "archive", "datestamp": "2023-08-20 00:15:29", "lastmod": "2023-10-20 22:08:37", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Arnett-C-H", "name": { "family": "Arnett", "given": "Charles H." }, "orcid": "0000-0002-1272-3797" }, { "id": "Bogacz-I", "name": { "family": "Bogacz", "given": "Isabel" } }, { "id": "Chatterjee-Ruchira", "name": { "family": "Chatterjee", "given": "Ruchira" }, "orcid": "0000-0002-0865-061X" }, { "id": "Yano-Junko", "name": { "family": "Yano", "given": "Junko" }, "orcid": "0000-0001-6308-9071" }, { "id": "Oyala-P-H", "name": { "family": "Oyala", "given": "Paul H." }, "orcid": "0000-0002-8761-4667" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Mixed-Valent Diiron \u00b5-Carbyne, \u00b5-Hydride Complexes: Implications for Nitrogenase", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2020 American Chemical Society. \n\nReceived: May 31, 2020; Published: September 25, 2020. \n\nWe are grateful to the NSF for funding (CHE-1905320 to T.A. and an NSF Graduate Research Fellowship to C.H.A.). We thank Prof. Jonas C. Peters and Prof. Ryan G. Hadt for insightful discussions and Prof. Peters for the use of his group's M\u00f6ssbauer spectrometer. We thank Michael Takase and Lawrence Henling for assistance with X-ray crystallography and David VanderVelde for assistance with NMR spectroscopy. Magnetic data was acquired at the University of California, Los Angeles with assistance from Dr. Ignacio Martini on a Quantum Design MPMS3 SQUID Magnetometer supported by the NSF (MRI-1625776). Support has been provided for the Caltech EPR Facility via an NSF grant (1531940) and the Dow Next Generation Educator Fund, which is also acknowledged for support of the X-ray diffraction and NMR instrumentation. The computations presented here were conducted on the Caltech High Performance Cluster partially supported by a grant from the Gordon and Betty Moore Foundation. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ja0c05920_si_001.cif
Supplemental Material - ja0c05920_si_002.pdf
", "abstract": "Binding of N\u2082 by the FeMo-cofactor of nitrogenase is believed to occur after transfer of 4 e\u207b and 4 H\u207a equivalents to the active site. Although pulse EPR studies indicate the presence of two Fe-(\u03bc-H)-Fe moieties, the structural and electronic features of this mixed valent intermediate remain poorly understood. Toward an improved understanding of this bioorganometallic cluster, we report herein that diiron \u03bc-carbyne complex (P\u2086ArC)Fe\u2082(\u03bc-H) can be oxidized and reduced, allowing for the first time spectral characterization of two EPR-active Fe(\u03bc-C)(\u03bc-H)Fe model complexes linked by a 2 e\u207b transfer which bear some resemblance to a pair of E_n and E_(n+2) states of nitrogenase. Both species populate S = 1/2 states at low temperatures, and the influence of valence (de)localization on the spectroscopic signature of the \u03bc-hydride ligand was evaluated by pulse EPR studies. Compared to analogous data for the {Fe\u2082(\u03bc-H)}\u2082 state of FeMoco (E\u2084(4H)), the data and analysis presented herein suggest that the hydride ligands in E\u2084(4H) bridge isovalent (most probably Fe^(III)) metal centers. Although electron transfer involves metal-localized orbitals, investigations of [(P\u2086ArC)Fe\u2082(\u03bc-H)]\u207a\u00b9 and [(P\u2086ArC)Fe\u2082(\u03bc-H)]\u207b\u00b9 by pulse EPR revealed that redox chemistry induces significant changes in Fe\u2013C covalency (\u221250% upon 2 e\u207b reduction), a conclusion further supported by X-ray absorption spectroscopy, \u2075\u2077Fe M\u00f6ssbauer studies, and DFT calculations. Combined, our studies demonstrate that changes in covalency buffer against the accumulation of excess charge density on the metals by partially redistributing it to the bridging carbon, thereby facilitating multielectron transformations.", "date": "2020-11-04", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "142", "number": "44", "publisher": "American Chemical Society", "pagerange": "18795-18813", "id_number": "CaltechAUTHORS:20200928-104114284", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200928-104114284", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-1905320" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "NSF", "grant_number": "MRI-1625776" }, { "agency": "NSF", "grant_number": "CHE-1531940" }, { "agency": "Dow Next Generation Educator Fund" }, { "agency": "Gordon and Betty Moore Foundation" } ] }, "doi": "10.1021/jacs.0c05920", "primary_object": { "basename": "ja0c05920_si_002.pdf", "url": "https://authors.library.caltech.edu/records/4njs4-k3188/files/ja0c05920_si_002.pdf" }, "related_objects": [ { "basename": "ja0c05920_si_001.cif", "url": "https://authors.library.caltech.edu/records/4njs4-k3188/files/ja0c05920_si_001.cif" } ], "resource_type": "article", "pub_year": "2020", "author_list": "Arnett, Charles H.; Bogacz, Isabel; et el." }, { "id": "https://authors.library.caltech.edu/records/b2126-s2h47", "eprint_id": 105082, "eprint_status": "archive", "datestamp": "2023-08-19 23:30:25", "lastmod": "2023-10-20 21:20:34", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Shoshani-M-M", "name": { "family": "Shoshani", "given": "Manar M." }, "orcid": "0000-0002-4051-3367" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Ligand architecture for triangular metal complexes: a high oxidation state Ni\u2083 cluster with proximal metal arrangement", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2020 The Royal Society of Chemistry. \n\nSubmitted 29 May 2020; Accepted 21 Jul 2020; First published 21 Jul 2020. \n\nWe thank Lawrence M. Henling and Mike Takase for crystallographic asistance and Paul H. Oyala for X-band EPR assistance. The authors are grateful to the Natural Sciences and Engineering Research Counsel of Canada (MMS), Dow (TA), and the NSF (NSF-1531940 for EPR instrumentation) for financial support. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - d0cc03816d1.pdf
Supplemental Material - d0cc03816d2.cif
", "abstract": "A new multidentate tetraanionic ligand platform for supporting trinuclear transition metal clusters has been developed. Two trisphenoxide phosphinimide ligands bind three Ni centers in a triangular arrangement. The phosphinimide donors bridge in \u00b5\u2083 fashion and the phenoxides complete a pseudo-square planar coordination sphere around each metal center. Electrochemical studies reveal two pseudo-reversible oxidation events at notably low potentials (\u22120.80 V and +0.05 V). The one electron oxidized species was characterized structurally, and it is assigned as a Ni^(III)-containing cluster.", "date": "2020-09-28", "date_type": "published", "publication": "Chemical Communications", "volume": "56", "number": "76", "publisher": "Royal Society of Chemistry", "pagerange": "11279-11282", "id_number": "CaltechAUTHORS:20200824-141345082", "issn": "1359-7345", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200824-141345082", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Natural Sciences and Engineering Research Council of Canada (NSERC)" }, { "agency": "Dow Chemical Company" }, { "agency": "NSF", "grant_number": "CHE-1531940" } ] }, "doi": "10.1039/d0cc03816d", "primary_object": { "basename": "d0cc03816d1.pdf", "url": "https://authors.library.caltech.edu/records/b2126-s2h47/files/d0cc03816d1.pdf" }, "related_objects": [ { "basename": "d0cc03816d2.cif", "url": "https://authors.library.caltech.edu/records/b2126-s2h47/files/d0cc03816d2.cif" } ], "resource_type": "article", "pub_year": "2020", "author_list": "Shoshani, Manar M. and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/gk4wt-5vg02", "eprint_id": 104987, "eprint_status": "archive", "datestamp": "2023-08-19 23:20:04", "lastmod": "2023-10-20 21:01:49", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ozden-Adnan", "name": { "family": "Ozden", "given": "Adnan" }, "orcid": "0000-0002-6924-1967" }, { "id": "Li-Fengwang", "name": { "family": "Li", "given": "Fengwang" }, "orcid": "0000-0003-1531-2966" }, { "id": "Garc\u0131\u0301a-de-Arquer-F-Pelayo", "name": { "family": "Garc\u0131\u0301a de Arquer", "given": "F. Pelayo" }, "orcid": "0000-0003-2422-6234" }, { "id": "Rosas-Hern\u00e1ndez-Alonso", "name": { "family": "Rosas-Hern\u00e1ndez", "given": "Alonso" }, "orcid": "0000-0002-0812-5591" }, { "id": "Thevenon-Arnaud", "name": { "family": "Thevenon", "given": "Arnaud" }, "orcid": "0000-0002-5543-6595" }, { "id": "Wang-Yuhang", "name": { "family": "Wang", "given": "Yuhang" }, "orcid": "0000-0001-5336-5183" }, { "id": "Hung-Sung-Fu", "name": { "family": "Hung", "given": "Sung-Fu" } }, { "id": "Wang-Xue", "name": { "family": "Wang", "given": "Xue" } }, { "id": "Chen-Bin", "name": { "family": "Chen", "given": "Bin" }, "orcid": "0000-0002-2106-7664" }, { "id": "Li-Jun", "name": { "family": "Li", "given": "Jun" } }, { "id": "Wicks-Joshua", "name": { "family": "Wicks", "given": "Joshua" }, "orcid": "0000-0001-7819-1167" }, { "id": "Luo-Mingchuan", "name": { "family": "Luo", "given": "Mingchuan" } }, { "id": "Wang-Ziyun", "name": { "family": "Wang", "given": "Ziyun" }, "orcid": "0000-0002-2817-8367" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Peters-J-C", "name": { "family": "Peters", "given": "Jonas C." }, "orcid": "0000-0002-6610-4414" }, { "id": "Sargent-Edward-H", "name": { "family": "Sargent", "given": "Edward H." }, "orcid": "0000-0003-0396-6495" }, { "id": "Sinton-David", "name": { "family": "Sinton", "given": "David" }, "orcid": "0000-0003-2714-6408" } ] }, "title": "High-Rate and Efficient Ethylene Electrosynthesis Using a Catalyst/Promoter/Transport Layer", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2020 American Chemical Society. \n\nReceived: June 10, 2020; Accepted: August 6, 2020; Published: August 14, 2020. \n\nThis work was financially supported by the Ontario Research Fund: Research Excellence Program, the Natural Sciences and Engineering Research Council (NSERC) of Canada, the CIFAR Bio-Inspired Solar Energy program and the Joint Centre of Artificial Synthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the US Department of Energy under award no. DE-SC0004993. X-ray absorption spectra were performed on SXRMB beamlines at the Canadian Light Source (CLS), which is supported by the Canada Foundation for Innovation, Natural Sciences and Engineering Research Council of Canada, the University of Saskatchewan, the Government of Saskatchewan, Western Economic Diversification Canada, the National Research Council Canada, and the Canadian Institutes of Health Research. The authors acknowledge Ontario Centre for the Characterization of Advanced Materials (OCCAM) for sample preparation and characterization facilities and thank Dr. Alexander H. Ip, Dr. Christine Gabardo and Mr. Colin P. O'Brien for useful discussions. A.T. acknowledges Marie Sk\u0142odowska-Curie Fellowship H2020-MSCA-IF-2017 (793471). J.L. acknowledges the Banting postdoctoral fellowship. D.S. acknowledges the NSERC E.W.R. Steacie Memorial Fellowship. \n\nAuthor Contributions: A.O. and F.L. contributed equally to this work. D.S. and E.H.S. supervised the project. A.O. conceived the idea and carried out the electrochemical experiments with advice from F.L.. A.T. and A.R.-H. synthesized and characterized the tetrahydro-phenanthrolinium. A.O. carried out Raman and EIS measurements. Y.W. and A.O. carried out SEM imaging. F.L. and S.F.H. designed the XAS measurements. S.-F.H. performed the XAS measurements. X.W. performed the NMR analysis and provided help in EIS measurements. B.C. and Y.W. performed the TEM analysis. J.W. performed XPS measurements. M.L., J.L., and Z.W. provided help in electrochemical experiments. A.O. and F.L. wrote the manuscript. F.P.G.A. provided help in manuscript writing. All authors discussed the results and assisted during manuscript preparation. \n\nThe authors declare no competing financial interest.\n\nSubmitted - Manuscript-clean-ACS.docx
Supplemental Material - nz0c01266_si_001.pdf
", "abstract": "Carbon dioxide (CO\u2082) electroreduction to valuable chemicals such as ethylene is an avenue to store renewable electricity and close the carbon cycle. Membrane electrode assembly (MEA) electrolyzers have attracted recent interest in light of their high stability and despite low productivity (a modest partial current density in CO\u2082-to-ethylene conversion of approximately 100 mA cm\u207b\u00b2). Here we present an adlayer functionalization catalyst design: a catalyst/tetrahydro-phenanthrolinium/ionomer (CTPI) interface in which the catalytically active copper is functionalized using a phenanthrolinium-derived film and a perfluorocarbon-based polymeric ionomer. We find, using electroanalytical tools and operando spectroscopies, that this hierarchical adlayer augments both the local CO\u2082 availability and the adsorption of the key reaction intermediate CO on the catalyst surface. Using this CTPI catalyst, we achieve an ethylene Faradaic efficiency of 66% at a partial current density of 208 mA cm\u207b\u00b2\u2014a 2-fold increase over the best prior MEA electrolyzer report\u2014and an improved full-cell energy efficiency of 21%.", "date": "2020-09-11", "date_type": "published", "publication": "ACS Energy Letters", "volume": "5", "number": "9", "publisher": "American Chemical Society", "pagerange": "2811-2818", "id_number": "CaltechAUTHORS:20200818-072409036", "issn": "2380-8195", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200818-072409036", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Ontario Research Fund-Research Excellence" }, { "agency": "Natural Sciences and Engineering Research Council of Canada (NSERC)" }, { "agency": "Canadian Institute for Advanced Research (CIFAR)" }, { "agency": "Joint Center for Artificial Photosynthesis (JCAP)" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0004993" }, { "agency": "Canada Foundation for Innovation" }, { "agency": "University of Saskatchewan" }, { "agency": "Government of Saskatchewan" }, { "agency": "Western Economic Diversification Canada" }, { "agency": "National Research Council of Canada" }, { "agency": "Canadian Institutes of Health Research (CIHR)" }, { "agency": "Marie Curie Fellowship", "grant_number": "793471" } ] }, "local_group": { "items": [ { "id": "JCAP" } ] }, "doi": "10.1021/acsenergylett.0c01266", "primary_object": { "basename": "Manuscript-clean-ACS.docx", "url": "https://authors.library.caltech.edu/records/gk4wt-5vg02/files/Manuscript-clean-ACS.docx" }, "related_objects": [ { "basename": "nz0c01266_si_001.pdf", "url": "https://authors.library.caltech.edu/records/gk4wt-5vg02/files/nz0c01266_si_001.pdf" } ], "resource_type": "article", "pub_year": "2020", "author_list": "Ozden, Adnan; Li, Fengwang; et el." }, { "id": "https://authors.library.caltech.edu/records/bmh6e-h6e30", "eprint_id": 103694, "eprint_status": "archive", "datestamp": "2023-08-22 06:20:04", "lastmod": "2023-10-20 16:36:55", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wan-Ruomeng", "name": { "family": "Wan", "given": "Ruomeng" } }, { "id": "Buss-J-A", "name": { "family": "Buss", "given": "Joshua A." }, "orcid": "0000-0002-3347-8583" }, { "id": "Horak-K-T", "name": { "family": "Horak", "given": "Kyle T." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "A Hemilabile Diphosphine Pyridine Pincer Ligand: \u03c3- and \u03c0-Binding in Molybdenum Coordination Complexes", "ispublished": "pub", "full_text_status": "public", "keywords": "Hemilabile Ligands; Pincer Complexes; Molybdenum; Transition Metal Nitride", "note": "\u00a9 2020 Published by Elsevier Ltd. \n\nReceived 5 February 2020, Revised 28 May 2020, Accepted 29 May 2020, Available online 4 June 2020. \n\nDedicated to John Bercaw on the occasion of his 75th birthday. Thank you, John, for your inspiring science, mentorship, and friendship!", "abstract": "A series of molybdenum compounds supported by a hemilabile pyridine diphosphine pincer ligand have been synthesized. The ligand demonstrates variable binding modes, adapting to the electronic and geometric requirements of the metal center. In Mo\u2070 and Mo^(II) polycarbonyl complexes, coordination through the \u03c3-donating pyridine nitrogen lone pair is observed. Upon oxidative group transfer with anionic azide, a Mo^(IV) nitride compound is formed, accompanied by a change in the ancillary ligand binding mode to the pyridine \u03c0-system. The \u03c3-coordination was restored by subsequent functionalization of the nitride moiety with either silyl electrophiles or protons. Protonation results in redox disproportionation with concomitant nitride functionalization. Characterization by single crystal X-ray diffraction, nuclear magnetic resonance, and infrared spectroscopy is discussed.", "date": "2020-09-01", "date_type": "published", "publication": "Polyhedron", "volume": "187", "publisher": "Elsevier", "pagerange": "Art. No. 114631", "id_number": "CaltechAUTHORS:20200604-123156381", "issn": "0277-5387", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200604-123156381", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1016/j.poly.2020.114631", "resource_type": "article", "pub_year": "2020", "author_list": "Wan, Ruomeng; Buss, Joshua A.; et el." }, { "id": "https://authors.library.caltech.edu/records/jbdan-k1m20", "eprint_id": 103300, "eprint_status": "archive", "datestamp": "2023-08-19 21:47:05", "lastmod": "2023-10-20 15:54:17", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Arnett-C-H", "name": { "family": "Arnett", "given": "Charles H." }, "orcid": "0000-0002-1272-3797" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Activation of an Open Shell, Carbyne-Bridged Diiron Complex Toward Binding of Dinitrogen", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2020 American Chemical Society. \n\nReceived: February 21, 2020; Published: April 14, 2020. \n\nWe are grateful to the NSF for funding (CHE-1905320 to T.A. and an NSF Graduate Research Fellowship to C.H.A.). We thank Prof. Jonas C. Peters for insightful discussions and for the use of his group's M\u00f6ssbauer spectrometer. We thank Michael Takase and Lawrence Henling for assistance with X-ray crystallography and David VanderVelde for assistance with NMR spectroscopy. Magnetic data was acquired at the University of California, Los Angeles with assistance from Dr. Ignacio Martini on a Quantum Design MPMS3 SQUID Magnetometer supported by the NSF (MRI-1625776). The Dow Next Generation Educator Fund is acknowledged for X-ray diffraction and NMR instrumentation. The computations presented here were conducted on the Caltech High Performance Cluster partially supported by a grant from the Gordon and Betty Moore Foundation. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ja0c01896_si_001.cif
Supplemental Material - ja0c01896_si_002.pdf
", "abstract": "Binding of N\u2082 by nitrogenase requires a reductive activation of the FeMo-cofactor, but the precise structure and atomic composition of FeMoco in its activated form is not well understood. However, recent crystallographic studies suggest that N\u2082 reduction may occur at a carbon-bridged diiron subunit of FeMoco. Toward modeling the activation of a Fe\u2013(\u03bc-C)\u2013Fe site toward N\u2082 binding, we synthesized a new dinucleating, hexaphosphine ligand derived from a 2,6-disubstituted toluene platform. Activation of the central methyl group of the ligand affords the diiron \u03bc-carbyne complex (P\u2086ArC)Fe\u2082 (\u03bc-H) featuring a biologically relevant Fe(\u03bc-carbyne)(\u03bc-H)Fe motif. SQUID magnetometry, M\u00f6ssbauer spectroscopy, and DFT calculations reveal that (P\u2086ArC)Fe\u2082 (\u03bc-H) has a well-isolated S = 1 ground state, distinguishing it from all other diiron \u03bc-carbyne complexes which are diamagnetic. Upon the addition of sources of H\u207a/e\u207b (H\u2082, TEMPO-H or HCl), (P\u2086ArC)Fe\u2082 (\u03bc-H) is activated toward N\u2082 binding, with concomitant protonation of the carbyne ligand. Although reaction with H\u2082 ultimately leads to complete protonation of the carbyne moiety, mechanistic investigations indicate that formation of a single C\u2013H bond, with concomitant cleavage of one Fe\u2013C bond, generates an iron-carbene intermediate capable of coordinating N\u2082.", "date": "2020-06-03", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "142", "number": "22", "publisher": "American Chemical Society", "pagerange": "10059-10068", "id_number": "CaltechAUTHORS:20200519-081454400", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200519-081454400", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-1905320" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "NSF", "grant_number": "MRI-1625776" }, { "agency": "Dow Next Generation Educator Fund" }, { "agency": "Gordon and Betty Moore Foundation" } ] }, "doi": "10.1021/jacs.0c01896", "primary_object": { "basename": "ja0c01896_si_001.cif", "url": "https://authors.library.caltech.edu/records/jbdan-k1m20/files/ja0c01896_si_001.cif" }, "related_objects": [ { "basename": "ja0c01896_si_002.pdf", "url": "https://authors.library.caltech.edu/records/jbdan-k1m20/files/ja0c01896_si_002.pdf" } ], "resource_type": "article", "pub_year": "2020", "author_list": "Arnett, Charles H. and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/p5691-g7h46", "eprint_id": 101650, "eprint_status": "archive", "datestamp": "2023-08-22 04:12:36", "lastmod": "2023-10-19 22:55:39", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Nam-Dae-Hyun", "name": { "family": "Nam", "given": "Dae-Hyun" }, "orcid": "0000-0002-0871-1355" }, { "id": "De-Luna-Phil", "name": { "family": "De Luna", "given": "Phil" }, "orcid": "0000-0002-7729-8816" }, { "id": "Rosas-Hern\u00e1ndez-Alonso", "name": { "family": "Rosas-Hern\u00e1ndez", "given": "Alonso" }, "orcid": "0000-0002-0812-5591" }, { "id": "Thevenon-Arnaud", "name": { "family": "Thevenon", "given": "Arnaud" }, "orcid": "0000-0002-5543-6595" }, { "id": "Li-Fengwang", "name": { "family": "Li", "given": "Fengwang" }, "orcid": "0000-0003-1531-2966" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Peters-J-C", "name": { "family": "Peters", "given": "Jonas C." }, "orcid": "0000-0002-6610-4414" }, { "id": "Shekhah-Osama", "name": { "family": "Shekhah", "given": "Osama" }, "orcid": "0000-0003-1861-9226" }, { "id": "Eddaoudi-Mohamed", "name": { "family": "Eddaoudi", "given": "Mohamed" }, "orcid": "0000-0003-1916-9837" }, { "id": "Sargent-Edward-H", "name": { "family": "Sargent", "given": "Edward H." }, "orcid": "0000-0003-0396-6495" } ] }, "title": "Molecular enhancement of heterogeneous CO\u2082 reduction", "ispublished": "pub", "full_text_status": "restricted", "keywords": "Engineering; Materials science", "note": "\u00a9 2020 Springer Nature Limited. \n\nReceived 16 January 2019; Accepted 08 January 2020; Published 25 February 2020. \n\nThis work was in part supported financially by the Natural Sciences and Engineering Research Council of Canada, the Ontario Research Fund: Research Excellence Program (ORF-RE-RE08-034), the Natural Resources Canada Clean Growth Program (CGP-17-0455) and CIFAR Bio-Inspired Solar Energy Program (FL-000719). This work was also supported by the Joint Center for Artificial Photosynthesis, a DOE Energy InnovationHub, supported through the Office of Science of the US Department of Energy under award no. DESC0004993, and was also based on work supported by the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under award no. OSR-2018-CPF-3665-03 and OSR-2019-CCF-1972.04. P.D.L. acknowledges the Natural Sciences and Engineering Research Council of Canada for support in the form of a Canada Graduate Scholarship and A.T. acknowledges the European Union's Horizon 2020 research and innovation programme under the Marie Sk\u0142odowska-Curie Action H2020-MSCA-IF-2017 (793471). \n\nThese authors contributed equally: Dae-Hyun Nam, Phil De Luna. \n\nThe authors declare no competing interests.", "abstract": "The electrocatalytic carbon dioxide reduction reaction (CO\u2082RR) addresses the need for storage of renewable energy in valuable carbon-based fuels and feedstocks, yet challenges remain in the improvement of electrosynthesis pathways for highly selective hydrocarbon production. To improve catalysis further, it is of increasing interest to lever synergies between heterogeneous and homogeneous approaches. Organic molecules or metal complexes adjacent to heterogeneous active sites provide additional binding interactions that may tune the stability of intermediates, improving catalytic performance by increasing Faradaic efficiency (product selectivity), as well as decreasing overpotential. We offer a forward-looking perspective on molecularly enhanced heterogeneous catalysis for CO\u2082RR. We discuss four categories of molecularly enhanced strategies: molecular-additive-modified heterogeneous catalysts, immobilized organometallic complex catalysts, reticular catalysts and metal-free polymer catalysts. We introduce present-day challenges in molecular strategies and describe a vision for CO2RR electrocatalysis towards multi-carbon products. These strategies provide potential avenues to address the challenges of catalyst activity, selectivity and stability in the further development of CO\u2082RR.", "date": "2020-03", "date_type": "published", "publication": "Nature Materials", "volume": "19", "number": "3", "publisher": "Nature Publishing Group", "pagerange": "266-276", "id_number": "CaltechAUTHORS:20200302-110558568", "issn": "1476-1122", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200302-110558568", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Natural Sciences and Engineering Research Council of Canada (NSERC)" }, { "agency": "Ontario Research Fund", "grant_number": "ORF-RE-RE08-034" }, { "agency": "Natural Resources Canada", "grant_number": "CGP-17-0455" }, { "agency": "Canadian Institute for Advanced Research (CIFAR)", "grant_number": "FL-000719" }, { "agency": "Joint Center for Artificial Photosynthesis (JCAP)" }, { "agency": "Department of Energy (DOE)", "grant_number": "DESC0004993" }, { "agency": "King Abdullah University of Science and Technology (KAUST)", "grant_number": "OSR-2018-CPF-3665-03" }, { "agency": "King Abdullah University of Science and Technology (KAUST)", "grant_number": "OSR-2019-CCF-1972.04" }, { "agency": "Marie Curie Fellowship", "grant_number": "793471" } ] }, "local_group": { "items": [ { "id": "JCAP" } ] }, "doi": "10.1038/s41563-020-0610-2", "resource_type": "article", "pub_year": "2020", "author_list": "Nam, Dae-Hyun; De Luna, Phil; et el." }, { "id": "https://authors.library.caltech.edu/records/vv86e-x7432", "eprint_id": 101109, "eprint_status": "archive", "datestamp": "2023-08-19 20:03:28", "lastmod": "2023-10-19 22:26:46", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lee-Heui-Beom", "name": { "family": "Lee", "given": "Heui Beom" }, "orcid": "0000-0002-9550-2649" }, { "id": "Marchiori-D-A", "name": { "family": "Marchiori", "given": "David A." }, "orcid": "0000-0001-9738-3674" }, { "id": "Chatterjee-Ruchira", "name": { "family": "Chatterjee", "given": "Ruchira" }, "orcid": "0000-0002-0865-061X" }, { "id": "Oyala-P-H", "name": { "family": "Oyala", "given": "Paul H." }, "orcid": "0000-0002-8761-4667" }, { "id": "Yano-Junko", "name": { "family": "Yano", "given": "Junko" }, "orcid": "0000-0001-6308-9071" }, { "id": "Britt-R-D", "name": { "family": "Britt", "given": "R. David" }, "orcid": "0000-0003-0889-8436" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "S = 3 Ground State for a Tetranuclear Mn^(IV)\u2084O\u2084 Complex Mimicking the S\u2083 State of the Oxygen Evolving Complex", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2020 American Chemical Society. \n\nReceived: September 25, 2019; Published: February 4, 2020. \n\nD.A.M. thanks Prof. Troy Stich (Wake Forest University) for valuable discussions and for reading the paper. This research was supported by the NIH (T.A. grant R01-GM102687), the Dreyfus Teacher\u2013Scholar Program (T.A.), Dow Next Generation Educator (instrumentation), NSF-1531940 (Caltech EPR facility), and the Division of Chemical Sciences, Geosciences, and Biosciences (R.D.B. grant DE-SC0007203) of the Office of Basic Energy Sciences of the U.S. Department of Energy. Part of this work (XAS data collection) was carried out at the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. XAS studies were performed with support of the Office of Science, OBES, Division of Chemical Sciences, Geosciences, and Biosciences (CSGB) of the DOE under contract no. DE-AC02-05CH11231 (J.Y.). \n\nAuthor Contributions: H.B.L. and D.A.M.: These authors contributed equally to this work.\n\nThe authors declare no competing financial interest.\n\nAccepted Version - jacs.9b10371.pdf
Accepted Version - nihms-1587212.pdf
Supplemental Material - ja9b10371_si_001.pdf
", "abstract": "The S\u2083 state is currently the last observable intermediate prior to O\u2013O bond formation at the oxygen-evolving complex (OEC) of Photosystem II, and its electronic structure has been assigned to a homovalent Mn^(IV)\u2084 core with an S = 3 ground state. While structural interpretations based on the EPR spectroscopic features of the S\u2083 state provide valuable mechanistic insight, corresponding synthetic and spectroscopic studies on tetranuclear complexes mirroring the Mn oxidation states of the S\u2083 state remain rare. Herein, we report the synthesis and characterization by XAS and multifrequency EPR spectroscopy of a Mn^(IV)\u2084O\u2084 cuboidal complex as a spectroscopic model of the S\u2083 state. Results show that this Mn^(IV)\u2084O\u2084 complex has an S = 3 ground state with isotropic \u2075\u2075Mn hyperfine coupling constants of \u221275, \u221288, \u221291, and 66 MHz. These parameters are consistent with an \u03b1\u03b1\u03b1\u03b2 spin topology approaching the trimer\u2013monomer magnetic coupling model of pseudo-octahedral Mn^(IV) centers. Importantly, the spin ground state changes from S = 1/2 to S = 3 as the OEC is oxidized from the S\u2082 state to the S\u2083 state. This same spin state change is observed following oxidation of the previously reported Mn^(III)Mn^(IV)\u2083O\u2084 cuboidal complex to the Mn^(IV)\u2084O\u2084 complex described here. This sets a synthetic precedent for the observed low-spin to high-spin conversion in the OEC.", "date": "2020-02-26", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "142", "number": "8", "publisher": "American Chemical Society", "pagerange": "3753-3761", "id_number": "CaltechAUTHORS:20200204-101055983", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200204-101055983", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Dow Next Generation Educator Fund" }, { "agency": "NSF", "grant_number": "CHE-1531940" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0007203" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-76SF00515" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-05CH11231" } ] }, "doi": "10.1021/jacs.9b10371", "pmcid": "PMC7236085", "primary_object": { "basename": "ja9b10371_si_001.pdf", "url": "https://authors.library.caltech.edu/records/vv86e-x7432/files/ja9b10371_si_001.pdf" }, "related_objects": [ { "basename": "jacs.9b10371.pdf", "url": "https://authors.library.caltech.edu/records/vv86e-x7432/files/jacs.9b10371.pdf" }, { "basename": "nihms-1587212.pdf", "url": "https://authors.library.caltech.edu/records/vv86e-x7432/files/nihms-1587212.pdf" } ], "resource_type": "article", "pub_year": "2020", "author_list": "Lee, Heui Beom; Marchiori, David A.; et el." }, { "id": "https://authors.library.caltech.edu/records/1bywh-85964", "eprint_id": 98698, "eprint_status": "archive", "datestamp": "2023-08-22 03:41:03", "lastmod": "2023-10-18 17:34:48", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Li-Fengwang", "name": { "family": "Li", "given": "Fengwang" }, "orcid": "0000-0003-1531-2966" }, { "id": "Thevenon-Arnaud", "name": { "family": "Thevenon", "given": "Arnaud" }, "orcid": "0000-0002-5543-6595" }, { "id": "Rosas-Hern\u00e1ndez-Alonso", "name": { "family": "Rosas-Hern\u00e1ndez", "given": "Alonso" }, "orcid": "0000-0002-0812-5591" }, { "id": "Han-Zhiji", "name": { "family": "Han", "given": "Zhiji" }, "orcid": "0000-0001-9349-1571" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Peters-J-C", "name": { "family": "Peters", "given": "Jonas C." }, "orcid": "0000-0002-6610-4414" } ] }, "title": "Molecular tuning of CO\u2082-to-ethylene conversion", "ispublished": "pub", "full_text_status": "public", "keywords": "Catalysis; Renewable energy", "note": "\u00a9 2019 Springer Nature Limited. \n\nReceived 21 December 2018; Accepted 01 October 2019; Published 20 November 2019. \n\nThis work was financially supported by the Ontario Research Fund:\nResearch Excellence Program, the Natural Sciences and Engineering Research Council (NSERC) of Canada, the CIFAR Bio-Inspired Solar Energy program, and the Joint Centre of Artificial Synthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993. All DFT computations were performed on the IBM BlueGene/Q supercomputer with support from the Southern Ontario Smart Computing Innovation Platform (SOSCIP). SOSCIP is funded by the Federal Economic Development Agency of Southern Ontario, the Province of Ontario, IBM Canada Ltd., Ontario Centres of Excellence, Mitacs and 15 Ontario academic member institutions. This research was enabled in part by support provided by Compute Ontario (www.computeontario.ca) and Compute Canada (www.computecanada.ca). This research used synchrotron resources of the Advanced Photon Source (APS), an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, and was\nsupported by the U.S. DOE under Contract No. DE-AC02-06CH11357, and the Canadian Light Source and its funding partners. We thank T. Wu and L. Ma for technical support at 9BM beamline of APS. D.S. acknowledges the NSERC E.W.R Steacie Memorial Fellowship. A.T. acknowledges Marie Sk\u0142odowska-Curie Fellowship H2020-MSCA-IF-2017 (793471). J.L. acknowledges the Banting postdoctoral fellowship. C.M.G. acknowledges NSERC for funding in\nthe form of a postdoctoral fellowship from the government of Canada. J.P.E. thanks NSERC, Hatch and the Government of Ontario for their support through graduate scholarships. \n\nAuthor contributions: E.H.S., T.A. and J.C.P. supervised this project. F.L. and Y.L. carried out electrochemical experiments. A.T. and A.R.H. carried out molecule synthesis and characterizations. Z.W. carried out DFT calculations. C.M.G. and F.L. conducted in situ Raman measurement. F.L. and A.O. carried out the membrane-electrode-assembly experiments. J. L. and F.L. performed X-ray spectroscopy measurements. Y.W. carried out SEM and EIS measurements. J.P.E. measured the contact angle. C.M. carried out the Comsol modelling. L.T. carried out EPR measurement under the supervision of R.D.B.. M.L. performed part of electrochemical experiments. Z. Q. L., X.W. and H.L. provided help in NMR analysis. C.M.G., C.P.O. and Y.X. provided help in membrane-electrode-assembly measurements. C.S.T. carried out AFM measurement. D.H.N. conducted XRD measurement. R.Q.B. carried out XPS measurement. C.T.D., T.Z, Y.C.L. and Z.H. provided help in materials synthesis and characterizations. F.L. and E.H.S. wrote the manuscript. All authors discussed the results and assisted during manuscript preparation. \n\nThe authors declare no competing interests.\n\nSupplemental Material - 41586_2019_1782_MOESM1_ESM.pdf
", "abstract": "The electrocatalytic carbon dioxide (CO\u2082) reduction reaction (CO\u2082RR) to value-added fuels and feedstocks provides a sustainable and carbon-neutral approach to the storage of intermittent renewable electricity. The highly selective generation of economically desirable C\u2082 products such as ethylene from CO\u2082RR remains a challenge. Tuning the stabilities of intermediates to favour a desired reaction pathway offers the opportunity to enhance selectivity, and this has recently been explored on copper (Cu) via control over morphology, grain boundaries7, facets, oxidation state and dopants. Unfortunately, the Faradaic efficiency for ethylene is still low in neutral media (60 per cent at a partial current density of 7 mA cm\u207b\u00b2 in the best catalyst reported so far), resulting in a low energy efficiency. Here we present a molecular tuning strategy\u2014the functionalization of the surface of electrocatalysts with organic molecules\u2014that stabilizes intermediates for enhanced CO\u2082RR to ethylene. Using electrochemical, operando/in situ spectroscopic and computational studies, we investigate the influence of a library of molecules, derived via electro-dimerization of arylpyridiniums, on Cu. We find that the adhered molecules improve the stabilization of an atop-bound CO intermediate, thereby favouring further reduction to ethylene. As a result of this strategy, we report the CO\u2082RR to ethylene with a Faradaic efficiency of 72 per cent at a partial current density of 230 mA cm\u207b\u00b2 in a liquid-electrolyte flow cell in neutral medium. We report stable ethylene electrosynthesis for 190 hours in a membrane-electrode-assembly-based system that provides a full-cell energy efficiency of 20 per cent. These findings indicate how molecular strategies can complement heterogeneous catalysts by stabilizing intermediates via local molecular tuning.", "date": "2020-01-23", "date_type": "published", "publication": "Nature", "volume": "577", "number": "7791", "publisher": "Nature Publishing Group", "pagerange": "509-513", "id_number": "CaltechAUTHORS:20190917-154117893", "issn": "0028-0836", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190917-154117893", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Ontario Research Fund-Research Excellence" }, { "agency": "Natural Sciences and Engineering Research Council of Canada (NSERC)" }, { "agency": "Canadian Institute for Advanced Research (CIFAR)" }, { "agency": "Joint Center for Artificial Photosynthesis (JCAP)" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0004993" }, { "agency": "Federal Economic Development Agency of Southern Ontario" }, { "agency": "Province of Ontario" }, { "agency": "IBM Canada Ltd." }, { "agency": "MITACS" }, { "agency": "Compute Ontario" }, { "agency": "Compute Canada" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-06CH11357" }, { "agency": "Canadian Light Source" }, { "agency": "Marie Curie Fellowship", "grant_number": "H2020-MSCA-IF-2017" }, { "agency": "Marie Curie Fellowship", "grant_number": "793471" } ] }, "local_group": { "items": [ { "id": "JCAP" } ] }, "doi": "10.1038/s41586-019-1782-2", "primary_object": { "basename": "41586_2019_1782_MOESM1_ESM.pdf", "url": "https://authors.library.caltech.edu/records/1bywh-85964/files/41586_2019_1782_MOESM1_ESM.pdf" }, "resource_type": "article", "pub_year": "2020", "author_list": "Li, Fengwang; Thevenon, Arnaud; et el." }, { "id": "https://authors.library.caltech.edu/records/r67bj-d3270", "eprint_id": 99940, "eprint_status": "archive", "datestamp": "2023-08-19 19:03:08", "lastmod": "2023-10-18 18:56:06", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Mathe-Zachary", "name": { "family": "Mathe", "given": "Zachary" }, "orcid": "0000-0002-4516-3511" }, { "id": "Pantazis-Dimitrios-A", "name": { "family": "Pantazis", "given": "Dimitrios A." }, "orcid": "0000-0002-2146-9065" }, { "id": "Lee-Heui-Beom", "name": { "family": "Lee", "given": "Heui Beom" }, "orcid": "0000-0002-9550-2649" }, { "id": "Gnewkow-Richard", "name": { "family": "Gnewkow", "given": "Richard" } }, { "id": "Van-Kuiken-Benjamin-E", "name": { "family": "Van Kuiken", "given": "Benjamin E." }, "orcid": "0000-0002-3650-7765" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "DeBeer-Serena", "name": { "family": "DeBeer", "given": "Serena" }, "orcid": "0000-0002-5196-3400" } ] }, "title": "Calcium Valence-to-Core X-ray Emission Spectroscopy: A Sensitive Probe of Oxo Protonation in Structural Models of the Oxygen-Evolving Complex", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2019 American Chemical Society. This is an open access article published under a Creative Commons Attribution (CC-BY) License, which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited. \n\nReceived: September 26, 2019; Published: November 19, 2019. \n\nThe authors acknowledge the Max Planck Society for funding. Z.M. thanks Yvonne Brandenburger and Fabian Strunk for technical expertise with the LabXES spectrometer, as well as Dr. Ragnar Bjornsson and Dr. Vijay Chilkuri for discussions of MO theory. Z.M. acknowledges the Deutscher Akademischer Austauschdienst for M.Sc. scholarship funding. T.A. is grateful to the NIH (Grant R01-GM102687B) for supporting the synthetic model studies. \n\nThe authors declare no competing financial interest.\n\nPublished - acs.inorgchem.9b02866.pdf
Supplemental Material - ic9b02866_si_001.pdf
", "abstract": "Calcium is an abundant, nontoxic metal that finds many roles in synthetic and biological systems including the oxygen-evolving complex (OEC) of photosystem II. Characterization methods for calcium centers, however, are underdeveloped compared to those available for transition metals. Valence-to-core X-ray emission spectroscopy (VtC XES) selectively probes the electronic structure of an element's chemical environment, providing insight that complements the geometric information available from other techniques. Here, the utility of calcium VtC XES is established using an in-house dispersive spectrometer in combination with density functional theory. Spectral trends are rationalized within a molecular orbital framework, and K\u03b2_(2,5) transitions, derived from molecular orbitals with primarily ligand p character, are found to be a promising probe of the calcium coordination environment. In particular, it is shown that calcium VtC XES is sensitive to the electronic structure changes that accompany oxo protonation in Mn\u2083CaO\u2084-based molecular mimics of the OEC. Through correlation to calculations, the potential of calcium VtC XES to address unresolved questions regarding the mechanism of biological water oxidation is highlighted.", "date": "2019-12-02", "date_type": "published", "publication": "Inorganic Chemistry", "volume": "58", "number": "23", "publisher": "American Chemical Society", "pagerange": "16292-16301", "id_number": "CaltechAUTHORS:20191120-074543683", "issn": "0020-1669", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20191120-074543683", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Max Planck Society" }, { "agency": "Deutscher Akademischer Austauschdienst (DAAD)" }, { "agency": "NIH", "grant_number": "R01-GM102687B" } ] }, "doi": "10.1021/acs.inorgchem.9b02866", "pmcid": "PMC6891804", "primary_object": { "basename": "acs.inorgchem.9b02866.pdf", "url": "https://authors.library.caltech.edu/records/r67bj-d3270/files/acs.inorgchem.9b02866.pdf" }, "related_objects": [ { "basename": "ic9b02866_si_001.pdf", "url": "https://authors.library.caltech.edu/records/r67bj-d3270/files/ic9b02866_si_001.pdf" } ], "resource_type": "article", "pub_year": "2019", "author_list": "Mathe, Zachary; Pantazis, Dimitrios A.; et el." }, { "id": "https://authors.library.caltech.edu/records/7je7v-wtf64", "eprint_id": 99914, "eprint_status": "archive", "datestamp": "2023-08-19 19:03:01", "lastmod": "2023-10-18 18:55:11", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Arnett-C-H", "name": { "family": "Arnett", "given": "Charles H." } }, { "id": "Kaiser-J-T", "name": { "family": "Kaiser", "given": "Jens T." }, "orcid": "0000-0002-5948-5212" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Remote Ligand Modifications Tune Electronic Distribution and Reactivity in Site-Differentiated, High-Spin Iron Clusters: Flipping Scaling Relationships", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2019 American Chemical Society. \n\nReceived: August 14, 2019; Published: November 18, 2019. \n\nThis research was supported by the NSF (CHE-1905320). T.A. is grateful for a Dreyfus fellowship. C.H.A. is grateful for an NSF Graduate Research Fellowship. We acknowledge the Gordon and Betty Moore Foundation and the Beckman Institute for their generous support of the Molecular Observatory at Caltech. Diffraction data was collected at the X-ray Crystallography Facility in the Beckman Institute at Caltech, which is supported by a Dow Next Generation Instrument Grant. Operations at SSRL are supported by the US DOE and NIH. We thank Michael Takase and Lawrence Henling for assistance with crystallography, Paul Oyala for assistance with EPR spectroscopy, and Matthew Chalkley and Dirk Schild for assistance with M\u00f6ssbauer spectroscopy. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ic9b02470_si_001.pdf
", "abstract": "We report the synthesis, characterization, and reactivity of [LFe\u2083O(^RArIm)\u2083Fe][OTf]\u2082, the first Hammett series of a site-differentiated cluster. The cluster reduction potentials and CO stretching frequencies shift as expected on the basis of the electronic properties of the ligand: electron-donating substituents result in more reducing clusters and weaker C\u2013O bonds. However, unusual trends in the energetics of their two sequential CO binding events with the substituent \u03c3_p parameters are observed. Specifically, introduction of electron-donating substituents suppresses the first CO binding event (\u0394\u0394H by as much as 7.9 kcal mol\u207b\u00b9) but enhances the second (\u0394\u0394H by as much as 1.9 kcal mol\u207b\u00b9). X-ray crystallography, including multiple-wavelength anomalous diffraction, M\u00f6ssbauer spectroscopy, and SQUID magnetometry, reveal that these substituent effects result from changes in the energetic penalty associated with electronic redistribution within the cluster, which occurs during the CO binding event.", "date": "2019-12-02", "date_type": "published", "publication": "Inorganic Chemistry", "volume": "58", "number": "23", "publisher": "American Chemical Society", "pagerange": "15971-15982", "id_number": "CaltechAUTHORS:20191118-160458797", "issn": "0020-1669", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20191118-160458797", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-1905320" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "Gordon and Betty Moore Foundation" }, { "agency": "Caltech Beckman Institute" }, { "agency": "Dow Next Generation Educator Fund" }, { "agency": "Department of Energy (DOE)" }, { "agency": "NIH" } ] }, "doi": "10.1021/acs.inorgchem.9b02470", "primary_object": { "basename": "ic9b02470_si_001.pdf", "url": "https://authors.library.caltech.edu/records/7je7v-wtf64/files/ic9b02470_si_001.pdf" }, "resource_type": "article", "pub_year": "2019", "author_list": "Arnett, Charles H.; Kaiser, Jens T.; et el." }, { "id": "https://authors.library.caltech.edu/records/8gaqr-e8y86", "eprint_id": 98794, "eprint_status": "archive", "datestamp": "2023-08-22 03:01:05", "lastmod": "2023-10-18 17:38:45", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Thevenon-Arnaud", "name": { "family": "Thevenon", "given": "Arnaud" }, "orcid": "0000-0002-5543-6595" }, { "id": "Rosas-Hern\u00e1ndez-Alonso", "name": { "family": "Rosas-Hern\u00e1ndez", "given": "Alonso" }, "orcid": "0000-0002-0812-5591" }, { "id": "Peters-J-C", "name": { "family": "Peters", "given": "Jonas C." }, "orcid": "0000-0002-6610-4414" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "In-situ Nanostructuring and Stabilization of Polycrystalline Copper by an Organic Salt Additive Promotes Electrocatalytic CO\u2082 Reduction to Ethylene", "ispublished": "pub", "full_text_status": "public", "keywords": "Carbon Dioxide; electrocatalysis; ethylene; nanocubes; Stability", "note": "\u00a9 2019 Wiley-\u2010VCH Verlag GmbH & Co. KGaA, Weinheim. \n\nAccepted manuscript online: 19 September 2019; Manuscript accepted: 19 September 2019; Manuscript revised: 13 August 2019; Manuscript received: 25 June 2019. \n\nNMR, AFM and XPS, SEM and EDX measurements were collected at the NMR Facility (Division of CCE), the Molecular Materials Research Center (Beckman Institute) and the Analytic Facilities (Division of Geological and Planetary Sciences) of the California Institute of Technology, respectively. This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993 and Marie Curie Fellowship H2020-MSCA-IF-2017 (793471) (A.T.). J.C.P. acknowledges additional support from the Resnick Sustainability Institute at Caltech. \n\nThe authors declare no conflict of interest.\n\nSupplemental Material - anie201907935-s1-supportinginformation.pdf
", "abstract": "Bridging homogeneous molecular systems with heterogeneous catalysts is a promising approach for the development of new electrodes, combining the advantages of both approaches. In the context of CO\u2082 electroreduction, molecular enhancement of planar copper electrodes has enabled promising advancement towards high Faradaic efficiencies for multicarbon products. Besides, nanostructured copper electrodes have also demonstrated enhanced performance at comparatively low overpotentials. Herein, we report a novel and convenient method for nanostructuring copper electrodes using N,N'\u2010ethylene\u2010phenanthrolinium dibromide as molecular additive. Selectivities up to 70% for C\u2265\u2082 products are observed for more than 40 h without significant change in the surface morphology. Mechanistic studies reveal several roles for the organic additive, including: the formation of cube\u2010like nanostructures by corrosion of the copper surface, the stabilization of these nanostructures during electrocatalysis by formation of a protective organic layer, and the promotion of C\u2265\u2082 products.", "date": "2019-11-18", "date_type": "published", "publication": "Angewandte Chemie International Edition", "volume": "58", "number": "47", "publisher": "Wiley", "pagerange": "16952-16958", "id_number": "CaltechAUTHORS:20190923-102748967", "issn": "1433-7851", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190923-102748967", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0004993" }, { "agency": "Marie Curie Fellowship", "grant_number": "H2020-MSCA-IF-2017" }, { "agency": "Resnick Sustainability Institute" } ] }, "local_group": { "items": [ { "id": "JCAP" }, { "id": "Resnick-Sustainability-Institute" } ] }, "doi": "10.1002/anie.201907935", "primary_object": { "basename": "anie201907935-s1-supportinginformation.pdf", "url": "https://authors.library.caltech.edu/records/8gaqr-e8y86/files/anie201907935-s1-supportinginformation.pdf" }, "resource_type": "article", "pub_year": "2019", "author_list": "Thevenon, Arnaud; Rosas-Hern\u00e1ndez, Alonso; et el." }, { "id": "https://authors.library.caltech.edu/records/e30w3-e6g36", "eprint_id": 95541, "eprint_status": "archive", "datestamp": "2023-08-19 18:46:13", "lastmod": "2023-10-20 20:19:48", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lee-Heui-Beom", "name": { "family": "Lee", "given": "Heui Beom" }, "orcid": "0000-0002-9550-2649" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Redox Tuning via Ligand-Induced Geometric Distortions at a YMn\u2083O\u2084 Cubane Model of the Biological Oxygen Evolving Complex", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2019 American Chemical Society. This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. \n\nReceived: February 20, 2019; Published: May 16, 2019. \n\nThis research was supported by the NIH (R01-GM102687B), the Dreyfus Teacher-Scholar Program (T.A.), and Dow Next Generation Educator (instrumentation). \n\nThe authors declare no competing financial interest.\n\nPublished - acs.inorgchem.9b00510.pdf
Supplemental Material - ic9b00510_si_001.pdf
", "abstract": "The function of proteins involved in electron transfer is dependent on cofactors attaining the necessary reduction potentials. We establish a mode of cluster redox tuning through steric pressure on a synthetic model related to Photosystem II. Resembling the cuboidal [CaMn\u2083O\u2084] subsite of the biological oxygen evolving complex (OEC), [Mn4O4] and [YMn\u2083O\u2084] complexes featuring ligands of different basicity and chelating properties were characterized by cyclic voltammetry. In the absence of ligand-induced distortions, increasing the basicity of the ligands results in a decrease of cluster reduction potential. Contraction of Y-oxo/Y\u2013Mn distances by 0.1/0.15 \u00c5 enforced by a chelating ligand results in an increase of cluster reduction potential even in the presence of strongly basic donors. Related protein-induced changes in Ca-oxo/Ca\u2013Mn distances may have similar effects in tuning the redox potential of the OEC through entatic states and may explain the cation size dependence on the progression of the S-state cycle.", "date": "2019-11-18", "date_type": "published", "publication": "Inorganic Chemistry", "volume": "58", "number": "22", "publisher": "American Chemical Society", "pagerange": "14998-15003", "id_number": "CaltechAUTHORS:20190516-105157000", "issn": "0020-1669", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190516-105157000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687B" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Dow Next Generation Educator Fund" } ] }, "doi": "10.1021/acs.inorgchem.9b00510", "pmcid": "PMC6876925", "primary_object": { "basename": "acs.inorgchem.9b00510.pdf", "url": "https://authors.library.caltech.edu/records/e30w3-e6g36/files/acs.inorgchem.9b00510.pdf" }, "related_objects": [ { "basename": "ic9b00510_si_001.pdf", "url": "https://authors.library.caltech.edu/records/e30w3-e6g36/files/ic9b00510_si_001.pdf" } ], "resource_type": "article", "pub_year": "2019", "author_list": "Lee, Heui Beom and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/vqxvh-61f48", "eprint_id": 98409, "eprint_status": "archive", "datestamp": "2023-08-19 18:12:28", "lastmod": "2023-10-18 17:20:25", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Buss-J-A", "name": { "family": "Buss", "given": "Joshua A." }, "orcid": "0000-0002-3347-8583" }, { "id": "Bailey-G-A", "name": { "family": "Bailey", "given": "Gwendolyn A." }, "orcid": "0000-0002-6636-4128" }, { "id": "Oppenheim-Julius-J", "name": { "family": "Oppenheim", "given": "Julius" }, "orcid": "0000-0002-5988-0677" }, { "id": "VanderVelde-D-G", "name": { "family": "VanderVelde", "given": "David G." }, "orcid": "0000-0002-2907-0366" }, { "id": "Goddard-W-A-III", "name": { "family": "Goddard", "given": "William A., III" }, "orcid": "0000-0003-0097-5716" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "CO Coupling Chemistry of a Terminal Mo Carbide: Sequential Addition of Proton, Hydride, and CO Releases Ethenone", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2019 American Chemical Society. \n\nReceived: July 22, 2019; Published: September 3, 2019. \n\nWe thank Larry Henling and Mike Takase for invaluable crystallographic assistance. J.A.B. is grateful for an NSF graduate research fellowship, G.A.B. for NSERC and Resnick Sustainability Institute fellowships, and J.O. for an Ernest H. Swift Summer Undergraduate Research Fellowship. We thank the NSF (CHE-1800501), the Dow Next Generation Education Fund (instrumentation), and Caltech for funding. The computational studies were supported by the NSF (CBET-1805022). \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ja9b07743_si_001.pdf
Supplemental Material - ja9b07743_si_002.cif
", "abstract": "The mechanism originally proposed by Fischer and Tropsch for carbon monoxide (CO) hydrogenative catenation involves C\u2013C coupling from a carbide-derived surface methylidene. A single molecular system capable of capturing these complex chemical steps is hitherto unknown. Herein, we demonstrate the sequential addition of proton and hydride to a terminal Mo carbide derived from CO. The resulting anionic methylidene couples with CO (1 atm) at low temperature (\u221278 \u00b0C) to release ethenone. Importantly, the synchronized delivery of two reducing equivalents and an electrophile, in the form of a hydride (H\u2013 = 2e\u2013 + H+), promotes alkylidene formation from the carbyne precursor and enables coupling chemistry, under conditions milder than those previously described with strong one-electron reductants and electrophiles. Thermodynamic measurements bracket the hydricity and acidity requirements for promoting methylidene formation from carbide as energetically viable relative to the heterolytic cleavage of H2. Methylidene formation prior to C\u2013C coupling proves critical for organic product release, as evidenced by direct carbide carbonylation experiments. Spectroscopic studies, a monosilylated model system, and Quantum Mechanics computations provide insight into the mechanistic details of this reaction sequence, which serves as a rare model of the initial stages of the Fischer\u2013Tropsch synthesis.", "date": "2019-10-02", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "141", "number": "39", "publisher": "American Chemical Society", "pagerange": "15664-15674", "id_number": "CaltechAUTHORS:20190904-110429088", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190904-110429088", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF Graduate Research Fellowship" }, { "agency": "Natural Sciences and Engineering Research Council of Canada (NSERC)" }, { "agency": "Resnick Sustainability Institute" }, { "agency": "Caltech Summer Undergraduate Research Fellowship (SURF)" }, { "agency": "NSF", "grant_number": "CHE-1800501" }, { "agency": "Dow Next Generation Educator Fund" }, { "agency": "NSF", "grant_number": "CBET-1805022" } ] }, "other_numbering_system": { "items": [ { "id": "1350", "name": "WAG" } ] }, "local_group": { "items": [ { "id": "Resnick-Sustainability-Institute" } ] }, "doi": "10.1021/jacs.9b07743", "primary_object": { "basename": "ja9b07743_si_001.pdf", "url": "https://authors.library.caltech.edu/records/vqxvh-61f48/files/ja9b07743_si_001.pdf" }, "related_objects": [ { "basename": "ja9b07743_si_002.cif", "url": "https://authors.library.caltech.edu/records/vqxvh-61f48/files/ja9b07743_si_002.cif" } ], "resource_type": "article", "pub_year": "2019", "author_list": "Buss, Joshua A.; Bailey, Gwendolyn A.; et el." }, { "id": "https://authors.library.caltech.edu/records/3j17m-25317", "eprint_id": 98748, "eprint_status": "archive", "datestamp": "2023-08-19 18:10:36", "lastmod": "2023-10-18 17:36:54", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Sampson-J", "name": { "family": "Sampson", "given": "Jessica" } }, { "id": "Choi-Gyeongshin", "name": { "family": "Choi", "given": "Gyeongshin" } }, { "id": "Akhtar-M-N", "name": { "family": "Akhtar", "given": "Muhammed Naseem" } }, { "id": "Jaseer-E-A", "name": { "family": "Jaseer", "given": "E. A." } }, { "id": "Theravalappil-R", "name": { "family": "Theravalappil", "given": "Rajesh" }, "orcid": "0000-0002-6022-6461" }, { "id": "Garcia-Nestor", "name": { "family": "Garcia", "given": "Nestor" } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Early Metal Di(pyridyl) Pyrrolide Complexes with Second Coordination Sphere Arene\u2212\u03c0 Interactions: Ligand Binding and Ethylene Polymerization", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2019 American Chemical Society. This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. \n\nReceived 19 June 2019. Accepted 27 August 2019. Published online 19 September 2019. \n\nMike Takase and Larry Henling are acknowledged for crystallographic assistance. The authors are grateful for the support provided by King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia, offered under the KFUPM-Caltech Research Collaboration. \n\nThe authors declare no competing financial interest.\n\nPublished - acsomega.9b01788.pdf
Supplemental Material - ao9b01788_si_001.cif
Supplemental Material - ao9b01788_si_002.pdf
", "abstract": "Early metal complexes supported by hemilabile, monoanionic di(pyridyl) pyrrolide ligands substituted with mesityl and anthracenyl groups were synthesized to probe the possibility of second coordination sphere arene\u2212\u03c0 interactions with ligands with potential for allosteric control in coordination chemistry, substrate activation, and olefin polymerization. Yttrium alkyl, indolide, and amide complexes were prepared and structurally characterized; close contacts between the anthracenyl substituents and Y-bound ligands are observed in the solid state. Titanium, zirconium, and hafnium tris(dimethylamido) complexes were synthesized, and their ethylene polymerization activity was tested. In the solid state structure of one of the Ti tris(dimethylamido) complexes, coordination of Ti to only one of the pyridine donors is observed pointing to the hemilabile character of the di(pyridyl) pyrrolide ligands.", "date": "2019-10-01", "date_type": "published", "publication": "ACS Omega", "volume": "4", "number": "14", "publisher": "American Chemical Society", "pagerange": "15879-15892", "id_number": "CaltechAUTHORS:20190919-113941856", "issn": "2470-1343", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190919-113941856", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "King Fahd University of Petroleum and Minerals (KFUPM)" }, { "agency": "Caltech" } ] }, "doi": "10.1021/acsomega.9b01788", "pmcid": "PMC6776977", "primary_object": { "basename": "ao9b01788_si_001.cif", "url": "https://authors.library.caltech.edu/records/3j17m-25317/files/ao9b01788_si_001.cif" }, "related_objects": [ { "basename": "ao9b01788_si_002.pdf", "url": "https://authors.library.caltech.edu/records/3j17m-25317/files/ao9b01788_si_002.pdf" }, { "basename": "acsomega.9b01788.pdf", "url": "https://authors.library.caltech.edu/records/3j17m-25317/files/acsomega.9b01788.pdf" } ], "resource_type": "article", "pub_year": "2019", "author_list": "Sampson, Jessica; Choi, Gyeongshin; et el." }, { "id": "https://authors.library.caltech.edu/records/zbsxs-54t29", "eprint_id": 95500, "eprint_status": "archive", "datestamp": "2023-08-19 16:20:44", "lastmod": "2023-10-20 20:17:44", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Reed-C-J", "name": { "family": "Reed", "given": "Christopher J." }, "orcid": "0000-0002-8774-5106" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "A Terminal Fe^(III)-Oxo in a Tetranuclear Cluster: Effects of Distal Metal Centers on Structure and Reactivity", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2019 American Chemical Society. \n\nReceived: March 22, 2019; Published: May 14, 2019. \n\nThis research was supported by the NIH (R01-GM102687B) and the Dreyfus Teacher-Scholar Program (T.A.). C.J.R. thanks the Resnick Sustainability Institute at Caltech for a fellowship. We thank Dr. Mike Takase and Larry Henling for assistance with crystallography, Prof. Jonas Peters for use of his group's M\u00f6ssbauer spectrometer, and the Dow Next Generation Educator Fund for instrumentation. \n\nThe authors declare no competing financial interest.\n\nAccepted Version - nihms-1583112.pdf
Supplemental Material - ja9b03157_si_001.cif
Supplemental Material - ja9b03157_si_002.pdf
", "abstract": "Tetranuclear Fe clusters have been synthesized bearing a terminal Fe^(III)\u2013oxo center stabilized by hydrogen-bonding interactions from pendant (tert-butylamino)pyrazolate ligands. This motif was supported in multiple Fe oxidation states, ranging from [Fe^(II)_2Fe^(III)_2] to [Fe^(III)_4]; two oxidation states were structurally characterized by single-crystal X-ray diffraction. The reactivity of the Fe^(III)\u2013oxo center in proton-coupled electron transfer with X\u2013H (X = C, O) bonds of various strengths was studied in conjunction with analysis of thermodynamic square schemes of the cluster oxidation states. These results demonstrate the important role of distal metal centers in modulating the reactivity of a terminal metal\u2013oxo.", "date": "2019-06-19", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "141", "number": "24", "publisher": "American Chemical Society", "pagerange": "9479-9484", "id_number": "CaltechAUTHORS:20190515-081947535", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190515-081947535", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687B" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Resnick Sustainability Institute" } ] }, "local_group": { "items": [ { "id": "Resnick-Sustainability-Institute" } ] }, "doi": "10.1021/jacs.9b03157", "pmcid": "PMC7207158", "primary_object": { "basename": "ja9b03157_si_001.cif", "url": "https://authors.library.caltech.edu/records/zbsxs-54t29/files/ja9b03157_si_001.cif" }, "related_objects": [ { "basename": "ja9b03157_si_002.pdf", "url": "https://authors.library.caltech.edu/records/zbsxs-54t29/files/ja9b03157_si_002.pdf" }, { "basename": "nihms-1583112.pdf", "url": "https://authors.library.caltech.edu/records/zbsxs-54t29/files/nihms-1583112.pdf" } ], "resource_type": "article", "pub_year": "2019", "author_list": "Reed, Christopher J. and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/8krac-hhp73", "eprint_id": 93855, "eprint_status": "archive", "datestamp": "2023-08-19 15:22:32", "lastmod": "2023-10-20 17:28:19", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Hirscher-Nathanael-A", "name": { "family": "Hirscher", "given": "Nathanael A." } }, { "id": "Perez-Sierra-Danny", "name": { "family": "Perez Sierra", "given": "Danny" } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Robust Chromium Precursors for Catalysis: Isolation and Structure of a Single-Component Ethylene Tetramerization Precatalyst", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2019 American Chemical Society.\n\nReceived: February 5, 2019; Published: March 15, 2019. \n\nWe are grateful to The Dow Chemical Company, Caltech, the WAVE program (D.P.), and Dow Next Generation Educator (instrumentation) for funding. We thank Dr. Sean Ewart for insightful discussions. \n\nThe authors declare no competing financial interest.\n\nAccepted Version - nihms-1068602.pdf
Supplemental Material - ja9b01387_si_001.cif
Supplemental Material - ja9b01387_si_002.pdf
", "abstract": "We have introduced a new class of stable organometallic Cr reagents (compounds 1\u20134) that are readily prepared, yet reactive enough to serve as precursors. They were used for ethylene tetramerization catalysis following stoichiometric activation by in situ protonation. This study highlights the importance of balancing stability with reactivity in generating an organometallic precursor that is useful in catalysis. Moreover, precursor 4 allowed for the isolation and crystallographic characterization of a room-temperature stable cationic species, (PNP)CrR_2+ (R = o-C_6H_4(CH_2)_2OMe, PNP = ^iPrN(PPh_2)_2). This complex (5) may be used as a single component precatalyst, without any alkylaluminum reagents. This result provides an unprecedented level of insight into the kind of structures that must be produced from more complicated activation processes.", "date": "2019-04-10", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "141", "number": "14", "publisher": "American Chemical Society", "pagerange": "6022-6029", "id_number": "CaltechAUTHORS:20190315-082340173", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190315-082340173", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" }, { "agency": "Caltech" }, { "agency": "WAVE Program" }, { "agency": "Dow Next Generation Educator Fund" } ] }, "doi": "10.1021/jacs.9b01387", "pmcid": "PMC7025812", "primary_object": { "basename": "ja9b01387_si_001.cif", "url": "https://authors.library.caltech.edu/records/8krac-hhp73/files/ja9b01387_si_001.cif" }, "related_objects": [ { "basename": "ja9b01387_si_002.pdf", "url": "https://authors.library.caltech.edu/records/8krac-hhp73/files/ja9b01387_si_002.pdf" }, { "basename": "nihms-1068602.pdf", "url": "https://authors.library.caltech.edu/records/8krac-hhp73/files/nihms-1068602.pdf" } ], "resource_type": "article", "pub_year": "2019", "author_list": "Hirscher, Nathanael A.; Perez Sierra, Danny; et el." }, { "id": "https://authors.library.caltech.edu/records/p3g6h-zy515", "eprint_id": 92766, "eprint_status": "archive", "datestamp": "2023-08-19 14:21:37", "lastmod": "2023-10-20 16:24:57", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lionetti-Davide", "name": { "family": "Lionetti", "given": "Davide" }, "orcid": "0000-0002-4937-886X" }, { "id": "Suseno-Sandy", "name": { "family": "Suseno", "given": "Sandy" } }, { "id": "Tsui-Emily-Y", "name": { "family": "Tsui", "given": "Emily Y." }, "orcid": "0000-0001-6419-3954" }, { "id": "Lu-Luo", "name": { "family": "Lu", "given": "Luo" } }, { "id": "Stich-Ttoy-A", "name": { "family": "Stich", "given": "Troy A." }, "orcid": "0000-0003-0710-1456" }, { "id": "Carsch-Kurtis-M", "name": { "family": "Carsch", "given": "Kurtis M." }, "orcid": "0000-0003-4432-7518" }, { "id": "Nielsen-Robert-J", "name": { "family": "Nielsen", "given": "Robert J." }, "orcid": "0000-0002-7962-0186" }, { "id": "Goddard-W-A-III", "name": { "family": "Goddard", "given": "William A., III" }, "orcid": "0000-0003-0097-5716" }, { "id": "Britt-R-David", "name": { "family": "Britt", "given": "R. David" }, "orcid": "0000-0003-0889-8436" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Effects of Lewis Acidic Metal Ions (M) on Oxygen-Atom Transfer Reactivity of Heterometallic Mn\u2083MO\u2084 Cubane and Fe\u2083MO(OH) and Mn\u2083MO(OH) Clusters", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2019 American Chemical Society. \n\nReceived: September 21, 2018. Publication Date (Web): February 7, 2019. \n\nAccession Codes: CCDC 1035166 and 1035222 contain the supplementary crystallographic data for this paper. \n\nThis work was supported by the California Institute of Technology and the NIH R01 GM102687A (T.A.). T.A. is a Dreyfus fellow. We thank Dr. Michael K. Takase and Lawrence M. Henling for assistance with X-ray crystallography. D.L. gratefully acknowledges a graduate fellowship from the Resnick Sustainability Institute at Caltech. K.C. and W.A.G. received support from the NSF (CBET-1512759). The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF Chemistry Research Instrumentation award to Caltech (CHE-0639094). Computational resources included the Extreme Science and Engineering Discovery Environment, which is supported by National Science Foundation Grant ACI-1548562. \n\nThe authors declare no competing financial interest.\n\nAccepted Version - nihms-1023538.pdf
Supplemental Material - ic8b02701_si_001.pdf
", "abstract": "The modulation of the reactivity of metal oxo species by redox inactive metals has attracted much interest due to the observation of redox inactive metal effects on processes involving electron transfer both in nature (the oxygen-evolving complex of Photosystem II) and in heterogeneous catalysis (mixed-metal oxides). Studies of small-molecule models of these systems have revealed numerous instances of effects of redox inactive metals on electron- and group-transfer reactivity. However, the heterometallic species directly involved in these transformations have rarely been structurally characterized and are often generated in situ. We have previously reported the preparation and structural characterization of multiple series of heterometallic clusters based on Mn\u2083 and Fe\u2083 cores and described the effects of Lewis acidity of the heterometal incorporated in these complexes on cluster reduction potential. To determine the effects of Lewis acidity of redox inactive metals on group transfer reactivity in structurally well-defined complexes, we studied [Mn\u2083MO_\u2084, [Mn\u2083MO(OH)], and [Fe\u2083MO(OH)] clusters in oxygen atom transfer (OAT) reactions with phosphine substrates. The qualitative rate of OAT correlates with the Lewis acidity of the redox inactive metal, confirming that Lewis acidic metal centers can affect the chemical reactivity of metal oxo species by modulating cluster electronics.", "date": "2019-02-18", "date_type": "published", "publication": "Inorganic Chemistry", "volume": "58", "number": "4", "publisher": "American Chemical Society", "pagerange": "2336-2345", "id_number": "CaltechAUTHORS:20190207-142044105", "issn": "0020-1669", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190207-142044105", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "NIH", "grant_number": "R01 GM102687A" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Resnick Sustainability Institute" }, { "agency": "NSF", "grant_number": "CBET-1512759" }, { "agency": "NSF", "grant_number": "CHE-0639094" }, { "agency": "NSF", "grant_number": "ACI-1548562" } ] }, "other_numbering_system": { "items": [ { "id": "1324", "name": "WAG" } ] }, "local_group": { "items": [ { "id": "Resnick-Sustainability-Institute" } ] }, "doi": "10.1021/acs.inorgchem.8b02701", "pmcid": "PMC6574207", "primary_object": { "basename": "ic8b02701_si_001.pdf", "url": "https://authors.library.caltech.edu/records/p3g6h-zy515/files/ic8b02701_si_001.pdf" }, "related_objects": [ { "basename": "nihms-1023538.pdf", "url": "https://authors.library.caltech.edu/records/p3g6h-zy515/files/nihms-1023538.pdf" } ], "resource_type": "article", "pub_year": "2019", "author_list": "Lionetti, Davide; Suseno, Sandy; et el." }, { "id": "https://authors.library.caltech.edu/records/e9mv3-4vz12", "eprint_id": 91501, "eprint_status": "archive", "datestamp": "2023-08-19 13:48:13", "lastmod": "2023-10-19 22:32:37", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Hirscher-N-A", "name": { "family": "Hirscher", "given": "Nathanael A." } }, { "id": "Labinger-J-A", "name": { "family": "Labinger", "given": "Jay A." }, "orcid": "0000-0002-1942-9232" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Isotopic labelling in ethylene oligomerization: addressing the issue of 1-octene vs. 1-hexene selectivity", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2018 The Royal Society of Chemistry. \n\nThe article was received on 12 Nov 2018, accepted on 13 Nov 2018 and first published on 17 Nov 2018. \n\nWe are grateful to The Dow Chemical Company and Caltech for funding. We thank Dr. Sean Ewart and Prof. John Bercaw for helpful discussions. \n\nThere are no conflicts to declare.\n\nSupplemental Material - c8dt04509g1_si.pdf
", "abstract": "The selectivity-determining mechanistic steps of ethylene tetramerization and trimerization are evaluated in light of isotopic labeling experiments. A mechanism based upon a shared chromacycloheptane intermediate rather than the C\u2013C coupling of chromacyclopentanes or Cr speciation into independent trimerization and tetramerization catalysts is consistent with the data, including observed upper limits on 1-octene selectivity.", "date": "2019-01-07", "date_type": "published", "publication": "Dalton Transactions", "volume": "48", "number": "1", "publisher": "Royal Society of Chemistry", "pagerange": "40-44", "id_number": "CaltechAUTHORS:20181205-101618765", "issn": "1477-9226", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181205-101618765", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" }, { "agency": "Caltech" } ] }, "doi": "10.1039/c8dt04509g", "primary_object": { "basename": "c8dt04509g1_si.pdf", "url": "https://authors.library.caltech.edu/records/e9mv3-4vz12/files/c8dt04509g1_si.pdf" }, "resource_type": "article", "pub_year": "2019", "author_list": "Hirscher, Nathanael A.; Labinger, Jay A.; et el." }, { "id": "https://authors.library.caltech.edu/records/ampwf-dav07", "eprint_id": 90871, "eprint_status": "archive", "datestamp": "2023-08-19 13:15:14", "lastmod": "2023-10-19 14:58:33", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lee-Heui-Beom", "name": { "family": "Lee", "given": "Heui Beom" }, "orcid": "0000-0002-9550-2649" }, { "id": "Shiau-Angela-A", "name": { "family": "Shiau", "given": "Angela A." } }, { "id": "Oyala-Paul-H", "name": { "family": "Oyala", "given": "Paul H." }, "orcid": "0000-0002-8761-4667" }, { "id": "Marchiori-David-A", "name": { "family": "Marchiori", "given": "David A." }, "orcid": "0000-0001-9738-3674" }, { "id": "Gul-Sheraz", "name": { "family": "Gul", "given": "Sheraz" }, "orcid": "0000-0001-8920-8737" }, { "id": "Chatterjee-Ruchira", "name": { "family": "Chatterjee", "given": "Ruchira" }, "orcid": "0000-0002-0865-061X" }, { "id": "Yano-Junko", "name": { "family": "Yano", "given": "Junko" }, "orcid": "0000-0001-6308-9071" }, { "id": "Britt-R-David", "name": { "family": "Britt", "given": "R. David" }, "orcid": "0000-0003-0889-8436" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Tetranuclear [Mn^(III)Mn_3^(IV)O_4] Complexes as Spectroscopic Models of the S_2 State of the Oxygen Evolving Complex in Photosystem II", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2018 American Chemical Society. \n\nReceived: September 13, 2018; Published: November 8, 2018. \n\nThis research was supported by the NIH (R01-GM102687B), the Dreyfus Teacher-Scholar Program (T.A.), Dow Next Generation Educator (instrumentation), NSF-1531940 (Caltech EPR facility), the Division of Chemical Sciences, Geosciences, and Biosciences (R.D.B. Grant DE-SC0007203) of the Office of Basic Energy Sciences of the U.S. Department of Energy. Part of this work (XAS data collection) was carried out at Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract DE-AC02-76SF00515. XAS studies were performed with support of the Office of Science, OBES, Division of Chemical Sciences, Geosciences, and Biosciences (CSGB) of the DOE under contract DE-AC02-05CH11231 (J.Y.). We thank Dr. Michael K. Takase and Mr. Lawrence M. Henling for assistance with X-ray crystallography and Dr. Ignacio B. Martini for SQUID magnetometry. \n\nThe authors declare no competing financial interest.\n\nAccepted Version - nihms-1023592.pdf
Supplemental Material - ja8b09961_si_001.pdf
Supplemental Material - ja8b09961_si_002.cif
", "abstract": "Despite extensive biochemical, spectroscopic, and computational studies, the mechanism of biological water oxidation by the oxygen evolving complex (OEC) of Photosystem II remains a subject of significant debate. Mechanistic proposals are guided by the characterization of reaction intermediates such as the S_2 state, which features two characteristic EPR signals at g = 2 and g = 4.1. Two nearly isoenergetic structural isomers have been proposed as the source of these distinct signals, but relevant structure\u2013electronic structure studies remain rare. Herein, we report the synthesis, crystal structure, electrochemistry, XAS, magnetic susceptibility, variable temperature CW-EPR, and pulse EPR data for a series of [Mn^(III)Mn_3^(IV)O_4] cuboidal complexes as spectroscopic models of the S_2 state of the OEC. Resembling the oxidation state and EPR spectra of the S_2 state of the OEC, these model complexes show two EPR signals, a broad low field signal and a multiline signal, that are remarkably similar to the biological system. The effect of systematic changes in the nature of the bridging ligands on spectroscopy were studied. Results show that the electronic structure of tetranuclear Mn complexes is highly sensitive to even small geometric changes and the nature of the bridging ligands. Our model studies suggest that the spectroscopic properties of the OEC may also react very sensitively to small changes in structure; the effect of protonation state and other reorganization processes need to be carefully assessed.", "date": "2018-12-12", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "140", "number": "49", "publisher": "American Chemical Society", "pagerange": "17175-17187", "id_number": "CaltechAUTHORS:20181113-112610015", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181113-112610015", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687B" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Dow Next Generation Educator Fund" }, { "agency": "NSF", "grant_number": "CHE-1531940" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0007203" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-76SF00515" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-05CH11231" } ] }, "doi": "10.1021/jacs.8b09961", "pmcid": "PMC6574184", "primary_object": { "basename": "ja8b09961_si_001.pdf", "url": "https://authors.library.caltech.edu/records/ampwf-dav07/files/ja8b09961_si_001.pdf" }, "related_objects": [ { "basename": "ja8b09961_si_002.cif", "url": "https://authors.library.caltech.edu/records/ampwf-dav07/files/ja8b09961_si_002.cif" }, { "basename": "nihms-1023592.pdf", "url": "https://authors.library.caltech.edu/records/ampwf-dav07/files/nihms-1023592.pdf" } ], "resource_type": "article", "pub_year": "2018", "author_list": "Lee, Heui Beom; Shiau, Angela A.; et el." }, { "id": "https://authors.library.caltech.edu/records/qp4er-sha49", "eprint_id": 90265, "eprint_status": "archive", "datestamp": "2023-08-22 00:27:37", "lastmod": "2023-10-18 23:19:45", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Buss-J-A", "name": { "family": "Buss", "given": "Joshua A." }, "orcid": "0000-0002-3347-8583" }, { "id": "Hirahara-Masanari", "name": { "family": "Hirahara", "given": "Masanari" } }, { "id": "Ueda-Yohei", "name": { "family": "Ueda", "given": "Yohei" } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Molecular Mimics of Heterogeneous Metal Phosphides: Thermochemistry, Hydride\u2010Proton Isomerism, and HER Reactivity", "ispublished": "pub", "full_text_status": "public", "keywords": "\u03bc-Phosphide; \u03bc-Phosphinidene; Thermochemistry; Proton Reduction; Molybdenum", "note": "\u00a9 2018 Wiley\u2010VCH Verlag GmbH & Co. KGaA, Weinheim. \n\nManuscript received: July 19, 2018; Revised manuscript received: September 18, 2018; Accepted manuscript online: October 12, 2018; Version of record online: November 14, 2018. \n\nWe thank Lawrence M. Henling and Dr. Michael K. Takase for crystallographic assistance and Dr. David VanderVelde for NMR expertise. T.A. is grateful for a Dreyfus fellowship and for NSF funding (CHE\u20101151918 and CHE\u20101800501), J.A.B. for an NSF graduate research fellowship, M.H. for funding from the Grant\u2010in\u2010Aid for Young Scientists (B) (17K18433), and Y.U. for financial support from the JSPS Research Fellowships for Young Scientists. We thank the Dow Next Generation Fund and the NSF (NSF\u20101531940) for instrumentation. \n\nThe authors declare no conflict of interest.\n\nSupplemental Material - anie201808307-s1-supportinginformation.pdf
", "abstract": "A new series of low\u2010valent dinuclear molybdenum complexes bearing phosphido or phosphinidene bridging ligands was synthesized as a structural model of heterogeneous metal phosphide catalysts. Addition of acid to a monocationic Mo_2\u2010\u03bc\u2010P complex results in phosphide protonation, affording a dicationic Mo_2\u2010\u03bc\u2010PH species. Alternatively, reaction of an isoelectronic Mo_2\u2010\u03bc\u2010P precursor with LiBEt_3H gives a Mo_2H\u2010\u03bc\u2010P complex. Mixing these species, one bearing a Mo\u2212H and the other a P\u2212H bond, results in facile H2 production at room temperature.", "date": "2018-12-10", "date_type": "published", "publication": "Angewandte Chemie International Edition", "volume": "57", "number": "50", "publisher": "Wiley", "pagerange": "16329-16333", "id_number": "CaltechAUTHORS:20181012-131902698", "issn": "1433-7851", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181012-131902698", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "NSF", "grant_number": "CHE-1800501" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "Japan Society for the Promotion of Science (JSPS)", "grant_number": "17K18433" }, { "agency": "Dow Next Generation Fund" }, { "agency": "NSF", "grant_number": "CHE-1531940" } ] }, "doi": "10.1002/anie.201808307", "primary_object": { "basename": "anie201808307-s1-supportinginformation.pdf", "url": "https://authors.library.caltech.edu/records/qp4er-sha49/files/anie201808307-s1-supportinginformation.pdf" }, "resource_type": "article", "pub_year": "2018", "author_list": "Buss, Joshua A.; Hirahara, Masanari; et el." }, { "id": "https://authors.library.caltech.edu/records/ngj26-esk19", "eprint_id": 89684, "eprint_status": "archive", "datestamp": "2023-08-19 11:35:26", "lastmod": "2023-10-18 22:55:17", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Low-Choon-Heng", "name": { "family": "Low", "given": "Choon Heng" } }, { "id": "Rosenberg-Jeffrey-N", "name": { "family": "Rosenberg", "given": "Jeffrey N." } }, { "id": "Lopez-Marco-A", "name": { "family": "Lopez", "given": "Marco A." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Oxidative Coupling with Zr(IV) Supported by a Noninnocent Anthracene-Based Ligand: Application to the Catalytic Cotrimerization of Alkynes and Nitriles to Pyrimidines", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2018 American Chemical Society. \n\nReceived: July 13, 2018. Published: August 28, 2018. \n\nWe are grateful to the Dreyfus Foundation (T.A.), the Agency of Science, Technology and Research (A*STaR), Singapore (C.H.L.), and the Caltech's SURF (J.N.R.) and WAVE (M.A.L.) programs for funding. We thank Lawrence M. Henling, and Michael K. Takase for crystallographic assistance, and David VanderVelde for advice on NMR. The NSF (CRIF:MU CHE0639094) and NIH (RR027690) are thanked for instrument grants to Caltech. \n\nThe authors declare no competing financial interest.\n\nAccepted Version - nihms-1583473.pdf
Supplemental Material - ja8b07418_si_001.cif
Supplemental Material - ja8b07418_si_002.pdf
", "abstract": "We report the synthesis and reactivity of Zr complexes supported by a 9,10-anthracenediyl-linked bisphenoxide ligand, L. Zr^(IV)LBn_2 (1) undergoes facile photolytic reduction with concomitant formation of bibenzyl and Zr^(IV)L(THF)_3 (2), which displays a two-electron reduced anthracene moiety. Leveraging ligand-stored reducing equivalents, 2 promotes the oxidative coupling of internal and terminal alkynes to isolable zirconacyclopentadiene complexes, demonstrating the reversible utilization of anthracene as a redox reservoir. With diphenylacetylene under CO, cyclopentadienone is formed stoichiometrically. 2 is competent for the catalytic formation of pyrimidines from alkynes and nitriles. Mechanistic studies suggest that selectivity for pyrimidine originates from preferred formation of an azazirconacyclopentadiene intermediate, which reacts preferentially with nitriles over alkynes.", "date": "2018-09-26", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "140", "number": "38", "publisher": "American Chemical Society", "pagerange": "11906-11910", "id_number": "CaltechAUTHORS:20180917-125104788", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180917-125104788", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Agency for Science, Technology and Research (A*STAR)" }, { "agency": "Caltech Summer Undergraduate Research Fellowship (SURF)" }, { "agency": "NSF", "grant_number": "CHE-0639094" }, { "agency": "NIH", "grant_number": "RR027690" } ] }, "doi": "10.1021/jacs.8b07418", "pmcid": "PMC7282345", "primary_object": { "basename": "ja8b07418_si_001.cif", "url": "https://authors.library.caltech.edu/records/ngj26-esk19/files/ja8b07418_si_001.cif" }, "related_objects": [ { "basename": "ja8b07418_si_002.pdf", "url": "https://authors.library.caltech.edu/records/ngj26-esk19/files/ja8b07418_si_002.pdf" }, { "basename": "nihms-1583473.pdf", "url": "https://authors.library.caltech.edu/records/ngj26-esk19/files/nihms-1583473.pdf" } ], "resource_type": "article", "pub_year": "2018", "author_list": "Low, Choon Heng; Rosenberg, Jeffrey N.; et el." }, { "id": "https://authors.library.caltech.edu/records/hv1jj-4ex53", "eprint_id": 88429, "eprint_status": "archive", "datestamp": "2023-08-19 11:12:59", "lastmod": "2023-10-18 22:03:13", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Reed-Christopher-J", "name": { "family": "Reed", "given": "Christopher J." }, "orcid": "0000-0002-8774-5106" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Thermodynamics of Proton and Electron Transfer in Tetranuclear Clusters with Mn\u2013OH\u2082/OH Motifs Relevant to H\u2082O Activation by the Oxygen Evolving Complex in Photosystem II", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2018 American Chemical Society. \n\nReceived: June 19, 2018; Published: July 31, 2018. \n\nThis research was supported by the NIH (R01-GM102687B) and the Dreyfus Teacher-Scholar Program (T.A.). C.J.R. thanks the Resnick Sustainability Institute at Caltech for a fellowship. We thank Dr. Mike Takase and Dr. Larry Henling for assistance with crystallography, Prof. Jonas Peters for use of his laboratory's M\u00f6ssbauer spectrometer, and the Dow Next Generation Educator Fund for instrumentation. \n\nThe authors declare no competing financial interest.\n\nAccepted Version - nihms-984247.pdf
Supplemental Material - ja8b06426_si_001.cif
Supplemental Material - ja8b06426_si_002.pdf
", "abstract": "We report the synthesis of site-differentiated heterometallic clusters with three Fe centers and a single Mn site that binds water and hydroxide in multiple cluster oxidation states. Deprotonation of Fe^(III/II)_3Mn^(II)\u2013OH\u2082 clusters leads to internal reorganization resulting in formal oxidation at Mn to generate Fe^(III/II)_3Mn^(III)\u2013OH. ^(57)Fe M\u00f6ssbauer spectroscopy reveals that oxidation state changes (three for Fe^(III/II)_3Mn\u2013OH\u2082 and four for Fe^(III/II)_3Mn\u2013OH clusters) occur exclusively at the Fe centers; the Mn center is formally Mn^(II) when water is bound and Mn^(III) when hydroxide is bound. Experimentally determined pK_a (17.4) of the [Fe^(III)\u2082Fe^(II)Mn^(II)\u2013OH\u2082] cluster and the reduction potentials of the [Fe_3Mn\u2013OH\u2082] and [Fe_3Mn\u2013OH] clusters were used to analyze the O\u2013H bond dissociation enthalpies (BDE_(O\u2013H)) for multiple cluster oxidation states. BDE_(O\u2013H) increases from 69 to 78 and 85 kcal/mol for the [Fe^(III)Fe^(II)\u2082Mn^(II)\u2013OH\u2082], [Fe^(III)\u2082Fe^(II)Mn^(II)\u2013OH\u2082], and [Fe^(III)_3Mn^(II)\u2013OH\u2082] clusters, respectively. Further insight of the proton and electron transfer thermodynamics of the [Fe_3Mn\u2013OH_x] system was obtained by constructing a potential\u2013pK_a diagram; the shift in reduction potentials of the [Fe_3Mn\u2013OH_x] clusters in the presence of different bases supports the BDE_(O\u2013H) values reported for the [Fe_3Mn\u2013OH\u2082] clusters. A lower limit of the pK_a for the hydroxide ligand of the [Fe_3Mn\u2013OH] clusters was estimated for two oxidation states. These data suggest BDE_(O\u2013H) values for the [Fe^(III)\u2082Fe^(II)Mn^(III)\u2013OH] and [Fe^(III)_3Mn^(III)\u2013OH] clusters are greater than 93 and 103 kcal/mol, which hints to the high reactivity expected of the resulting [Fe_3Mn\u2550O] in this and related multinuclear systems.", "date": "2018-08-29", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "140", "number": "34", "publisher": "American Chemical Society", "pagerange": "10900-10908", "id_number": "CaltechAUTHORS:20180801-091754883", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180801-091754883", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687B" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Resnick Sustainability Institute" }, { "agency": "Dow Chemical Company" } ] }, "local_group": { "items": [ { "id": "Resnick-Sustainability-Institute" } ] }, "doi": "10.1021/jacs.8b06426", "pmcid": "PMC6277146", "primary_object": { "basename": "ja8b06426_si_001.cif", "url": "https://authors.library.caltech.edu/records/hv1jj-4ex53/files/ja8b06426_si_001.cif" }, "related_objects": [ { "basename": "ja8b06426_si_002.pdf", "url": "https://authors.library.caltech.edu/records/hv1jj-4ex53/files/ja8b06426_si_002.pdf" }, { "basename": "nihms-984247.pdf", "url": "https://authors.library.caltech.edu/records/hv1jj-4ex53/files/nihms-984247.pdf" } ], "resource_type": "article", "pub_year": "2018", "author_list": "Reed, Christopher J. and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/s7b9m-dte62", "eprint_id": 88119, "eprint_status": "archive", "datestamp": "2023-08-19 11:05:16", "lastmod": "2023-10-18 21:48:23", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Buss-J-A", "name": { "family": "Buss", "given": "Joshua A." }, "orcid": "0000-0002-3347-8583" }, { "id": "VanderVelde-D-G", "name": { "family": "VanderVelde", "given": "David G." }, "orcid": "0000-0002-2907-0366" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Lewis Acid Enhancement of Proton Induced CO_2 Cleavage: Bond Weakening and Ligand Residence Time Effects", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2018 American Chemical Society. \n\nReceived: June 8, 2018; Published: July 23, 2018. \n\nWe thank Larry Henling and Mike Takase for invaluable crystallographic assistance. T.A. is grateful for a Dreyfus fellowship and J.A.B. for a NSF graduate research fellowship. We thank the NSF (CHE-1151918 and CHE-1800501), the Dow Next Generation Education Fund (for instrumentation at Caltech), and Caltech for funding. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ja8b05874_si_001.cif
Supplemental Material - ja8b05874_si_002.pdf
", "abstract": "Though Lewis acids (LAs) have been shown to have profound effects on carbon dioxide (CO_2) reduction catalysis, the underlying cause of the improved reactivity remains unclear. Herein, we report a well-defined molecular system for probing the role of LA additives in the reduction of CO_2 to carbon monoxide (CO) and water. Mo(0) CO_2 complex (2) forms adducts with a series of LAs, demonstrating CO_2 activation that correlates linearly with the strength of the LA. Protons induce C\u2013O cleavage of these LA adducts, in contrast to the CO_2 displacement primarily observed in the absence of LA. CO_2 cleavage shows dependence on both bond activation and the residence time of the bound small molecule, demonstrating the influence of both kinetic and thermodynamic factors on promoting productive CO_2 reduction chemistry.", "date": "2018-08-15", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "140", "number": "32", "publisher": "American Chemical Society", "pagerange": "10121-10125", "id_number": "CaltechAUTHORS:20180723-094941372", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180723-094941372", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "NSF", "grant_number": "CHE\u20101800501" }, { "agency": "Dow Next Generation Education Fund" }, { "agency": "Caltech" } ] }, "doi": "10.1021/jacs.8b05874", "primary_object": { "basename": "ja8b05874_si_001.cif", "url": "https://authors.library.caltech.edu/records/s7b9m-dte62/files/ja8b05874_si_001.cif" }, "related_objects": [ { "basename": "ja8b05874_si_002.pdf", "url": "https://authors.library.caltech.edu/records/s7b9m-dte62/files/ja8b05874_si_002.pdf" } ], "resource_type": "article", "pub_year": "2018", "author_list": "Buss, Joshua A.; VanderVelde, David G.; et el." }, { "id": "https://authors.library.caltech.edu/records/znz8s-nxs90", "eprint_id": 86937, "eprint_status": "archive", "datestamp": "2023-08-21 23:43:22", "lastmod": "2023-10-18 20:43:19", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Buss-J-A", "name": { "family": "Buss", "given": "Joshua A." }, "orcid": "0000-0002-3347-8583" }, { "id": "Cheng-Christine", "name": { "family": "Cheng", "given": "Christine" } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "A Low-Valent Molybdenum Nitride Complex: Reduction Promotes Carbonylation Chemistry", "ispublished": "pub", "full_text_status": "public", "keywords": "group transfer; Molybdenum; terminal nitrides; carbonylation", "note": "\u00a9 2018 Wiley\u2010VCH Verlag GmbH & Co. KGaA, Weinheim. \n\nManuscript received: March 28, 2018; Revised manuscript received: May 31, 2018; Accepted manuscript online: June 5, 2018; Version of record online: July 4, 2018. \n\nWe thank Lawrence\u2005M. Henling and Dr. Mike Takase for crystallographic assistance, Dr. David VanderVelde for NMR expertise, and Dr. Gwendolyn\u2005A. Bailey for collecting IR and EA data. T.A. is grateful for a Dreyfus fellowships and J.A.B. for an NSF graduate research fellowship. This research was supported by the NSF, grant number CHE\u20101151918 (T.A.), and Caltech. \n\nThe authors declare no conflict of interest.\n\nSupplemental Material - anie201803728-sup-0001-si1.pdf
", "abstract": "Toward nitrogen functionalization, reactive terminal transition metal nitrides with high d\u2010electron counts are of interest. A series of terminal Mo^(IV) nitride complexes were prepared within the context of exploring nitride/carbonyl coupling to cyanate. Reduction affords the first Mo^(II) nitrido complex, an early metal nitride with four valence d\u2010electrons. The binding mode of the para\u2010terphenyl diphosphine ancillary ligand changes to stabilize an electronic configuration with a high electron count and a formal M\u2212N bond order of three. Even with an intact Mo\u2261N bond, this low\u2010valent nitrido complex proves to be highly reactive, readily undergoing N\u2010atom transfer upon addition of CO, releasing cyanate anion.", "date": "2018-07-26", "date_type": "published", "publication": "Angewandte Chemie International Edition", "volume": "57", "number": "31", "publisher": "Wiley", "pagerange": "9670-9674", "id_number": "CaltechAUTHORS:20180608-143739694", "issn": "1433-7851", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180608-143739694", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "NSF", "grant_number": "CHE-1151918" } ] }, "doi": "10.1002/anie.201803728", "primary_object": { "basename": "anie201803728-sup-0001-si1.pdf", "url": "https://authors.library.caltech.edu/records/znz8s-nxs90/files/anie201803728-sup-0001-si1.pdf" }, "resource_type": "article", "pub_year": "2018", "author_list": "Buss, Joshua A.; Cheng, Christine; et el." }, { "id": "https://authors.library.caltech.edu/records/dkq07-en795", "eprint_id": 85494, "eprint_status": "archive", "datestamp": "2023-08-19 08:52:28", "lastmod": "2023-10-18 18:16:34", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Arnett-Charles-H", "name": { "family": "Arnett", "given": "Charles H." }, "orcid": "0000-0002-1272-3797" }, { "id": "Chalkley-Matthew-J", "name": { "family": "Chalkley", "given": "Matthew J." }, "orcid": "0000-0002-0484-7335" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "A Thermodynamic Model for Redox-Dependent Binding of Carbon Monoxide at Site-Differentiated, High Spin Iron Clusters", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2018 American Chemical Society. \n\nReceived: February 15, 2018; Published: March 28, 2018.\n\nThis research was supported by the NIH (R01-GM102687B). T.A. is grateful for a Dreyfus fellowship. C.H.A. gratefully acknowledges an NSF Graduate Research Fellowship. M.J.C. gratefully acknowledges a Caltech Environment Microbial Interactions (CEMI) Fellowship. We thank Michael Takase and Lawrence Henling for assistance with crystallography, Heui Boom Lee for assistance with SQUID magnetometry, and Paul Oyala assistance with EPR spectroscopy (NSF-1531940 for EPR instrumentation). We thank Graham de Ruiter, Joshua Buss, and Christopher Reed for insightful discussions.\n\nThe authors declare no competing financial interest.\n\nAccepted Version - nihms-995850.pdf
Supplemental Material - ja8b01825_si_001.cif
Supplemental Material - ja8b01825_si_002.pdf
", "abstract": "Binding of N_2 and CO by the FeMo-cofactor of nitrogenase depends on the redox level of the cluster, but the extent to which pure redox chemistry perturbs the affinity of high spin iron clusters for \u03c0-acids is not well understood. Here, we report a series of site-differentiated iron clusters which reversibly bind CO in redox states Fe^(II)_4 through Fe^(II)Fe^(III)_3. One electron redox events result in small changes in the affinity for (at most ~400-fold) and activation of CO (at most 28 cm^(-1) for \u03bd_(CO)). The small influence of redox chemistry on the affinity of these high spin, valence-localized clusters for CO is in stark contrast to the large enhancements (10^5-10^(22) fold) in \u03c0-acid affinity reported for monometallic and low spin bimetallic iron complexes, where redox chemistry occurs exclusively at the ligand binding site. While electron-loading at metal centers remote from the substrate binding site has minimal influence on the CO binding energetics (~1 kcal\u00b7mol^(-1)), it provides a conduit for CO binding at an Fe^(III) center. Indeed, internal electron transfer from these remote sites accommodates binding of CO at an Fe^(III), with a small energetic penalty arising from redox reorganization (~ 2.6 kcal\u00b7mol^(-1)). The ease with which these clusters redistribute electrons in response to ligand binding highlights a potential pathway for coordination of N_2 and CO by FeMoco, which may occur on an oxidized edge of the cofactor.", "date": "2018-04-25", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "140", "number": "16", "publisher": "American Chemical Society", "pagerange": "5569-5578", "id_number": "CaltechAUTHORS:20180329-110229274", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180329-110229274", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687B" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "Caltech Center for Environmental Microbial Interactions (CEMI)" }, { "agency": "NSF", "grant_number": "CHE-1531940" } ] }, "local_group": { "items": [ { "id": "Caltech-Center-for-Environmental-Microbial-Interactions-(CEMI)" } ] }, "doi": "10.1021/jacs.8b01825", "pmcid": "PMC6452638", "primary_object": { "basename": "ja8b01825_si_002.pdf", "url": "https://authors.library.caltech.edu/records/dkq07-en795/files/ja8b01825_si_002.pdf" }, "related_objects": [ { "basename": "nihms-995850.pdf", "url": "https://authors.library.caltech.edu/records/dkq07-en795/files/nihms-995850.pdf" }, { "basename": "ja8b01825_si_001.cif", "url": "https://authors.library.caltech.edu/records/dkq07-en795/files/ja8b01825_si_001.cif" } ], "resource_type": "article", "pub_year": "2018", "author_list": "Arnett, Charles H.; Chalkley, Matthew J.; et el." }, { "id": "https://authors.library.caltech.edu/records/1hra1-hpk42", "eprint_id": 84172, "eprint_status": "archive", "datestamp": "2023-08-19 07:26:33", "lastmod": "2023-10-18 15:57:13", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Shida-Naoki", "name": { "family": "Shida", "given": "Naoki" } }, { "id": "Buss-J-A", "name": { "family": "Buss", "given": "Joshua A." }, "orcid": "0000-0002-3347-8583" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Mild electrochemical synthesis of metal phosphides with dibenzo-7-phosphanorbornadiene derivatives: mechanistic insights and application to proton reduction in water", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2018 The Royal Society of Chemistry. \n\nReceived 23rd November 2017, Accepted 19th December 2017, First published on 20th December 2017. \n\nWe thank Lawrence M. Henling and Dr Mike Takase for crystallographic assistance, Dr David Vandervelde for help with NMR experiments. T. A. thanks Caltech and the Dreyfus Foundation for funding. Parts of these studies were funded by NSF CHE-1151918 and King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia, offered under the KFUPM-Caltech Research Collaboration. N. S. is grateful for a Grant-in-Aid for JSPS Research Fellow (No. 16J07350) and J. A. B. for an NSF graduate research fellowship. \n\nThere are no conflicts to declare.\n\nSupplemental Material - c7cc09003j1_si.pdf
Supplemental Material - c7cc09003j2.cif
", "abstract": "Transition metal phosphide films were synthesized using a mild electrochemical method. Dibenzo-7-phosphanorbornadiene derivatives (XPA) are introduced as versatile precursors to amorphous metal phosphide electrocatalysts for proton reduction in acidic water. Homogeneous model reactions reveal distinct reactivity between XPA and nickel in different oxidation states, with Ni(0) resulting in Ni_xP_y formation.", "date": "2018-01-21", "date_type": "published", "publication": "Chemical Communications", "volume": "54", "number": "7", "publisher": "Royal Society of Chemistry", "pagerange": "767-770", "id_number": "CaltechAUTHORS:20180108-142905197", "issn": "1359-7345", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180108-142905197", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "King Fahd University of Petroleum and Minerals (KFUPM)" }, { "agency": "Japan Society for the Promotion of Science (JSPS)", "grant_number": "16J07350" }, { "agency": "NSF Graduate Research Fellowship" } ] }, "doi": "10.1039/c7cc09003j", "primary_object": { "basename": "c7cc09003j2.cif", "url": "https://authors.library.caltech.edu/records/1hra1-hpk42/files/c7cc09003j2.cif" }, "related_objects": [ { "basename": "c7cc09003j1_si.pdf", "url": "https://authors.library.caltech.edu/records/1hra1-hpk42/files/c7cc09003j1_si.pdf" } ], "resource_type": "article", "pub_year": "2018", "author_list": "Shida, Naoki; Buss, Joshua A.; et el." }, { "id": "https://authors.library.caltech.edu/records/gw5pd-4jk25", "eprint_id": 82618, "eprint_status": "archive", "datestamp": "2023-08-19 06:01:51", "lastmod": "2023-10-17 22:33:46", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Hirscher-N-A", "name": { "family": "Hirscher", "given": "Nathanael A." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Stoichiometrically Activated Catalysts for Ethylene Tetramerization using Diphosphinoamine-Ligated Cr Tris(hydrocarbyl) Complexes", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2017 American Chemical Society. \n\nReceived: September 14, 2017. Publication Date (Web): October 23, 2017. \n\nWe are grateful to The Dow Chemical Company and Caltech for funding. We thank Sean Ewart, David Laitar, Mari Rosen, Joshua Buss, and Dinesh Aluthge for insightful discussions and Larry Henling and Mike Takase for assistance with crystallography. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - om7b00706_si_001.pdf
", "abstract": "A new, stoichiometric activation mode is presented for Cr-PNP (PNP = diphosphinoamine) complexes for ethylene tetramerization catalysis. To access suitable precatalysts, two robust Cr(III) multiaryl compounds were synthesized as THF adducts. These complexes are supported by a facially coordinated bis(aryl) ligand with an additional ether donor. From these precursors, Cr-PNP tris(hydrocarbyl) complexes were synthesized. Using 1 equiv of Br\u00f8nsted acid as an activator, an active species for the catalytic tetramerization of ethylene was produced, without the need for excess alkylaluminum reagents.", "date": "2017-11-13", "date_type": "published", "publication": "Organometallics", "volume": "36", "number": "21", "publisher": "American Chemical Society", "pagerange": "4107-4110", "id_number": "CaltechAUTHORS:20171024-130627004", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20171024-130627004", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" }, { "agency": "Caltech" } ] }, "doi": "10.1021/acs.organomet.7b00706", "primary_object": { "basename": "om7b00706_si_001.pdf", "url": "https://authors.library.caltech.edu/records/gw5pd-4jk25/files/om7b00706_si_001.pdf" }, "resource_type": "article", "pub_year": "2017", "author_list": "Hirscher, Nathanael A. and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/qkg8b-ssr81", "eprint_id": 81285, "eprint_status": "archive", "datestamp": "2023-08-21 22:11:29", "lastmod": "2023-10-17 19:43:20", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Buss-J-A", "name": { "family": "Buss", "given": "Joshua A." }, "orcid": "0000-0002-3347-8583" }, { "id": "Oyala-P-H", "name": { "family": "Oyala", "given": "Paul H." }, "orcid": "0000-0002-8761-4667" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Terminal Molybdenum Phosphides with d Electrons: Radical Character Promotes Coupling Chemistry", "ispublished": "pub", "full_text_status": "public", "keywords": "group transfer; molybdenum; phosphide coupling; pulse EPR; terminal phosphides", "note": "\u00a9 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. \n\nManuscript received: August 2, 2017; Accepted manuscript online: September 6, 2017; Version of record online: October 10, 2017. \n\nWe thank Lawrence M. Henling and Dr. Mike Takase for crystallographic assistance, Dr. David VanderVelde for help with NMR experiments, and Dr. A. Velian and Prof. C. C. Cummins for stimulating discussions. T.A. is grateful for Sloan, Cottrell, and Dreyfus fellowships and J.A.B. for an NSF graduate research fellowship. This research was supported by the NSF, grant numbers CHE-1151918 (T.A.) and NSF-1531940 (EPR instrumentation), and Caltech.\n\nAccepted Version - Buss_et_al-2017-Angewandte_Chemie.pdf
Supplemental Material - anie201707921-sup-0001-SI1.pdf
", "abstract": "A terminal Mo phosphide was prepared via group transfer of both P- and Cl-atoms from chloro-substituted dibenzo-7\u03bb^3-phosphanorbornadiene. This compound represents the first structurally characterized terminal transition metal phosphide with valence d electrons. In the tetragonal ligand field, these electrons populate an orbital of d_(xy) parentage, an electronic configuration that accommodates both metal d-electrons and a formal M\u2261P triple bond. Single electron oxidation affords a transient open shell terminal phosphide cation with significant spin density on P, as corroborated by CW and pulsed EPR characterization. Facile P-P bond formation occurs from this species via intermolecular phosphide coupling.", "date": "2017-11-13", "date_type": "published", "publication": "Angewandte Chemie International Edition", "volume": "56", "number": "46", "publisher": "Wiley", "pagerange": "14502-14506", "id_number": "CaltechAUTHORS:20170911-095556744", "issn": "1433-7851", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170911-095556744", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Cottrell Scholar of Research Corporation" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "NSF", "grant_number": "CHE-1531940" }, { "agency": "Caltech" } ] }, "doi": "10.1002/anie.201707921", "primary_object": { "basename": "Buss_et_al-2017-Angewandte_Chemie.pdf", "url": "https://authors.library.caltech.edu/records/qkg8b-ssr81/files/Buss_et_al-2017-Angewandte_Chemie.pdf" }, "related_objects": [ { "basename": "anie201707921-sup-0001-SI1.pdf", "url": "https://authors.library.caltech.edu/records/qkg8b-ssr81/files/anie201707921-sup-0001-SI1.pdf" } ], "resource_type": "article", "pub_year": "2017", "author_list": "Buss, Joshua A.; Oyala, Paul H.; et el." }, { "id": "https://authors.library.caltech.edu/records/3k56e-8df91", "eprint_id": 82539, "eprint_status": "archive", "datestamp": "2023-08-19 05:57:44", "lastmod": "2023-10-17 22:30:16", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Reed-Christopher-J", "name": { "family": "Reed", "given": "Christopher J." }, "orcid": "0000-0002-8774-5106" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Tetranuclear Fe Clusters with a Varied Interstitial Ligand: Effects on the Structure, Redox Properties, and Nitric Oxide Activation", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2017 American Chemical Society. \n\nReceived: August 17, 2017. Publication Date (Web): October 20, 2017. \n\nThis research was supported by the NIH (Grant R01-GM102687B) and the Dreyfus Teacher\u2013Scholar Program (to T.A.). C.J.R. thanks the Resnick Sustainability Institute at Caltech for a fellowship. We thank Mike Takase and Larry Henling for assistance with crystallography and Jonas Peters for use of his laboratory's M\u00f6ssbauer spectrometer. C.J.R. is grateful to Graham de Ruiter and Niklas Thompson for insightful discussions. \n\nThe authors declare no competing financial interest.\n\nAccepted Version - nihms915080.pdf
Supplemental Material - ic7b02114_si_001.pdf
", "abstract": "A new series of tetranuclear Fe clusters displaying an interstitial \u03bc_4-F ligand was prepared for a comparison to previously reported \u03bc_4-O analogues. With a single nitric oxide (NO) coordinated as a reporter of small-molecule activation, the \u03bc_4-F clusters were characterized in five redox states, from Fe^(II)_3{FeNO}^8 to Fe^(III)_3{FeNO}^7, with NO stretching frequencies ranging from 1680 to 1855 cm^(\u20131), respectively. Despite accessing more reduced states with an F\u2013 bridge, a two-electron reduction of the distal Fe centers is necessary for the \u03bc_4-F clusters to activate NO to the same degree as the \u03bc_4-O system; consequently, NO reactivity is observed at more positive potentials with \u03bc_4-O than \u03bc_4-F. Moreover, the \u03bc_4-O ligand better translates redox changes of remote metal centers to diatomic ligand activation. The implication for biological active sites is that the higher-charge bridging ligand is more effective in tuning cluster properties, including the involvement of remote metal centers, for small-molecule activation.", "date": "2017-11-06", "date_type": "published", "publication": "Inorganic Chemistry", "volume": "56", "number": "21", "publisher": "American Chemical Society", "pagerange": "13360-13367", "id_number": "CaltechAUTHORS:20171020-132701117", "issn": "0020-1669", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20171020-132701117", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687B" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Resnick Sustainability Institute" } ] }, "local_group": { "items": [ { "id": "Resnick-Sustainability-Institute" } ] }, "doi": "10.1021/acs.inorgchem.7b02114", "pmcid": "PMC6277142", "primary_object": { "basename": "nihms915080.pdf", "url": "https://authors.library.caltech.edu/records/3k56e-8df91/files/nihms915080.pdf" }, "related_objects": [ { "basename": "ic7b02114_si_001.pdf", "url": "https://authors.library.caltech.edu/records/3k56e-8df91/files/ic7b02114_si_001.pdf" } ], "resource_type": "article", "pub_year": "2017", "author_list": "Reed, Christopher J. and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/kaf4a-acp74", "eprint_id": 81070, "eprint_status": "archive", "datestamp": "2023-08-19 04:53:32", "lastmod": "2023-10-17 19:23:41", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kubin-Markus", "name": { "family": "Kubin", "given": "Markus" } }, { "id": "Kanady-Jabob-S", "name": { "family": "Kanady", "given": "Jacob S." } }, { "id": "Tsui-Emily-Y", "name": { "family": "Tsui", "given": "Emily Y." }, "orcid": "0000-0001-6419-3954" }, { "id": "Suseno-Sandy", "name": { "family": "Suseno", "given": "Sandy" } }, { "id": "Han-Zhiji", "name": { "family": "Han", "given": "Zhiji" }, "orcid": "0000-0001-9349-1571" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Soft x-ray absorption spectroscopy of metalloproteins and high-valent metal-complexes at room temperature using free-electron lasers", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2017 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). \n\nReceived 6 June 2017; accepted 15 August 2017; published online 1 September 2017. \n\nThis work was supported by the Director, Office of Science, Office of Basic Energy Sciences (OBES), Division of Chemical Sciences, Geosciences, and Biosciences (CSGB) of the Department of Energy (DOE) under contract DE-AC02-05CH11231 (J.Y. and V.K.Y.) for X-ray methodology and instrumentation, the National Institutes of Health (NIH) under Grant Nos. GM110501 (J.Y.) for instrumentation development for XFEL experiments and GM055302 (V.K.Y.) for PS II biochemistry, structure, and mechanism, the Ruth L. Kirschstein National Research Service Award (5 F32 GM116423\u201002, F.D.F.), the Human Frontiers Science under Project Award No. RGP0063/2013 310 (J.Y., U.B., and Ph. W.), the K&A Wallenberg foundation (J.M., Grant No. 2011.0055), Energimyndigheten (J.M., Grant No. 36648\u20101), Vetenskapsr\u00e5det (J.M., Grant No. 2016\u201005183), and the Helmholtz Virtual Institute \"Dynamic Pathways in Multidimensional Landscapes.\" The SSRL Structural Molecular Biology Program (T.K.) was supported by the DOE Office of Biological and Environmental Research and by the National Institutes of Health, National Institute of General Medical Sciences (including P41GM103393). This research was carried out on the SXR Instrument at the Linac Coherent Light Source (LCLS), a division of SLAC National Accelerator Laboratory and an Office of Science user facility operated by Stanford University for the U.S. Department of Energy. The SXR Instrument was funded by a consortium whose membership includes the LCLS, Stanford University, through the Stanford Institute for Materials Energy Sciences (SIMES), Lawrence Berkeley National Laboratory (LBNL), University of Hamburg through the BMBF priority program FSP 301, and the Center for Free Electron Laser Science (CFEL). NIH (R01-GM102687A) is acknowledged for supporting the synthesis of model cluster complexes (T.A.). We would like to acknowledge the Swedish Research Council for supporting the theoretical efforts discussed here. We would like to thank the staff at the SXR beam line for their support in this experiment and Dan DePonte and the Sample Environment Department at LCLS for providing the GDVN nozzles and support for the injection of the model compounds.\n\nPublished - 1_2E4986627.pdf
Supplemental Material - psii_l-edge_6_june_17_suppinfo.pdf
", "abstract": "X-ray absorption spectroscopy at the L-edge of 3d transition metals provides unique information on the local metal charge and spin states by directly probing 3d-derived molecular orbitals through 2p-3d transitions. However, this soft x-ray technique has been rarely used at synchrotron facilities for mechanistic studies of metalloenzymes due to the difficulties of x-ray-induced sample damage and strong background signals from light elements that can dominate the low metal signal. Here, we combine femtosecond soft x-ray pulses from a free-electron laser with a novel x-ray fluorescence-yield spectrometer to overcome these difficulties. We present L-edge absorption spectra of inorganic high-valent Mn complexes (Mn \u223c 6\u201315\u2009mmol/l) with no visible effects of radiation damage. We also present the first L-edge absorption spectra of the oxygen evolving complex (Mn_4CaO_5) in Photosystem II (Mn\u2009<\u20091\u2009mmol/l) at room temperature, measured under similar conditions. Our approach opens new ways to study metalloenzymes under functional conditions.", "date": "2017-09", "date_type": "published", "publication": "Structural Dynamics", "volume": "4", "number": "5", "publisher": "American Institute of Physics", "pagerange": "Art. No. 054307", "id_number": "CaltechAUTHORS:20170901-105945251", "issn": "2329-7778", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170901-105945251", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-05CH11231" }, { "agency": "NIH", "grant_number": "GM110501" }, { "agency": "NIH", "grant_number": "GM055302" }, { "agency": "NIH Predoctoral Fellowship", "grant_number": "5 F32 GM116423\u201002" }, { "agency": "Human Frontier Science Program", "grant_number": "RGP0063/2013 310" }, { "agency": "Knut and Alice Wallenberg Foundation", "grant_number": "2011.0055" }, { "agency": "Energimyndigheten", "grant_number": "36648-1" }, { "agency": "Vetenskapsr\u00e5det", "grant_number": "2016\u201005183" }, { "agency": "Helmholtz Virtual Institute" }, { "agency": "NIH", "grant_number": "P41GM103393" }, { "agency": "Stanford Linear Accelerator Center" }, { "agency": "Lawrence Berkeley National Laboratory" }, { "agency": "Bundesministerium f\u00fcr Bildung und Forschung (BMBF)", "grant_number": "FSP 301" }, { "agency": "NIH", "grant_number": "R01-GM102687A" } ] }, "doi": "10.1063/1.4986627", "pmcid": "PMC5586166", "primary_object": { "basename": "1_2E4986627.pdf", "url": "https://authors.library.caltech.edu/records/kaf4a-acp74/files/1_2E4986627.pdf" }, "related_objects": [ { "basename": "psii_l-edge_6_june_17_suppinfo.pdf", "url": "https://authors.library.caltech.edu/records/kaf4a-acp74/files/psii_l-edge_6_june_17_suppinfo.pdf" } ], "resource_type": "article", "pub_year": "2017", "author_list": "Kubin, Markus; Kanady, Jacob S.; et el." }, { "id": "https://authors.library.caltech.edu/records/9q310-2n919", "eprint_id": 79307, "eprint_status": "archive", "datestamp": "2023-08-19 04:44:06", "lastmod": "2023-10-26 14:47:35", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Han-Zhiji", "name": { "family": "Han", "given": "Zhiji" }, "orcid": "0000-0001-9349-1571" }, { "id": "Kortlever-Ruud", "name": { "family": "Kortlever", "given": "Ruud" } }, { "id": "Chen-Hsiang-Yun", "name": { "family": "Chen", "given": "Hsiang-Yun" }, "orcid": "0000-0002-6461-1519" }, { "id": "Peters-J-C", "name": { "family": "Peters", "given": "Jonas C." }, "orcid": "0000-0002-6610-4414" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "CO_2 Reduction Selective for C_(\u22652) Products on Polycrystalline Copper with N-Substituted Pyridinium Additives", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2017 American Chemical Society. ACS AuthorChoice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. \n\nReceived: April 26, 2017; Published: July 21, 2017. \n\nNMR and XPS spectra were collected at the NMR Facility (Division of CCE) and Molecular Materials Research Center (Beckman Institute) of the California Institute of Technology, respectively. This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993. \n\nThe authors declare no competing financial interest.\n\nPublished - acscentsci.7b00180.pdf
Supplemental Material - oc7b00180_si_001.pdf
Supplemental Material - oc7b00180_si_002.cif
", "abstract": "Electrocatalytic CO_2 reduction to generate multicarbon products is of interest for applications in artificial photosynthetic schemes. This is a particularly attractive goal for CO_2 reduction by copper electrodes, where a broad range of hydrocarbon products can be generated but where selectivity for C\u2013C coupled products relative to CH_4 and H_2 remains an impediment. Herein we report a simple yet highly selective catalytic system for CO_2 reduction to C_(\u22652) hydrocarbons on a polycrystalline Cu electrode in bicarbonate aqueous solution that uses N-substituted pyridinium additives. Selectivities of 70\u201380% for C_2 and C_3 products with a hydrocarbon ratio of C_(\u22652)/CH4significantly greater than 100 have been observed with several additives. ^(13)C-labeling studies verify CO_2 to be the sole carbon source in the C_(\u22652) hydrocarbons produced. Upon electroreduction, the N-substituted pyridinium additives lead to film deposition on the Cu electrode, identified in one case as the reductive coupling product of N-arylpyridinium. Product selectivity can also be tuned from C_(\u22652) species to H_2 (\u223c90%) while suppressing methane with certain N-heterocyclic additives.", "date": "2017-08-23", "date_type": "published", "publication": "ACS Central Science", "volume": "3", "number": "8", "publisher": "American Chemical Society", "pagerange": "853-859", "id_number": "CaltechAUTHORS:20170724-131758454", "issn": "2374-7943", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170724-131758454", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0004993" } ] }, "local_group": { "items": [ { "id": "JCAP" } ] }, "doi": "10.1021/acscentsci.7b00180", "pmcid": "PMC5571460", "primary_object": { "basename": "acscentsci.7b00180.pdf", "url": "https://authors.library.caltech.edu/records/9q310-2n919/files/acscentsci.7b00180.pdf" }, "related_objects": [ { "basename": "oc7b00180_si_001.pdf", "url": "https://authors.library.caltech.edu/records/9q310-2n919/files/oc7b00180_si_001.pdf" }, { "basename": "oc7b00180_si_002.cif", "url": "https://authors.library.caltech.edu/records/9q310-2n919/files/oc7b00180_si_002.cif" } ], "resource_type": "article", "pub_year": "2017", "author_list": "Han, Zhiji; Kortlever, Ruud; et el." }, { "id": "https://authors.library.caltech.edu/records/4gh7g-8wn95", "eprint_id": 78757, "eprint_status": "archive", "datestamp": "2023-08-21 21:34:25", "lastmod": "2023-10-26 00:21:47", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "De-Ruiter-Graham", "name": { "family": "De Ruiter", "given": "Graham" } }, { "id": "Carsch-Kurtis-M", "name": { "family": "Carsch", "given": "Kurtis M." }, "orcid": "0000-0003-4432-7518" }, { "id": "Takase-Michael-K", "name": { "family": "Takase", "given": "Michael K." }, "orcid": "0000-0001-8365-3645" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Selectivity of C\u2212H vs. C\u2212F Bond Oxygenation by Homo- and Heterometallic Fe_4, Fe_3Mn, and Mn_4 Clusters", "ispublished": "pub", "full_text_status": "public", "keywords": "C-H bond oxygenation; C-F bond oxygenation; multimetallic complexes; oxygen atom transfer; clusters", "note": "\u00a9 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. \n\nManuscript received: May 19, 2017; Accepted manuscript online: June 28, 2017; Version of record online: July 24, 2017. \n\nThis research was supported by the NIH (R01-GM102687B).\nT.A. is grateful for a Dreyfus fellowship. K.M.C. is grateful for a Summer Undergraduate Research Fellowship. We thank Lawrence M. Henling for assistance with X-ray crystallography. We would also like to thank Mona Shahgholi for assistance with mass spectrometry.\n\nAccepted Version - Ruiter_et_al-2017-Chemistry_-_A_European_Journal.pdf
Accepted Version - nihms913583.pdf
Supplemental Material - chem201702302-sup-0001-SI1.pdf
", "abstract": "A series of tetranuclear [LM_3(HFArPz)_3OM'][OTf]_2 (M, M' = Fe or Mn) clusters that displays 3-(2-fluorophenyl)pyrazolate (HFArPz) as bridging ligand is reported. With these complexes manganese is demonstrated to facilitate C(sp^2)\u2212F bond oxygenation via a putative terminal metal-oxo species. Moreover, the presence of both ortho C(sp^2)\u2212H and C(sp^2)\u2212F bonds in proximity provides an opportunity to investigate the selectivity of intramolecular C(sp^2)\u2212X bond oxygenation (X = H or F) in these isostructural compounds. With iron as the apical metal center (M' = Fe) C(sp^2)\u2212F bond oxygenation occurs almost exclusively, whereas with manganese (M' = Mn) the opposite reactivity is preferred.", "date": "2017-08-10", "date_type": "published", "publication": "Chemistry: a European Journal", "volume": "23", "number": "45", "publisher": "John Wiley & Sons", "pagerange": "10744-10748", "id_number": "CaltechAUTHORS:20170705-095520227", "issn": "0947-6539", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170705-095520227", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687B" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Caltech Summer Undergraduate Research Fellowship (SURF)" } ] }, "doi": "10.1002/chem.201702302", "pmcid": "PMC5659184", "primary_object": { "basename": "Ruiter_et_al-2017-Chemistry_-_A_European_Journal.pdf", "url": "https://authors.library.caltech.edu/records/4gh7g-8wn95/files/Ruiter_et_al-2017-Chemistry_-_A_European_Journal.pdf" }, "related_objects": [ { "basename": "chem201702302-sup-0001-SI1.pdf", "url": "https://authors.library.caltech.edu/records/4gh7g-8wn95/files/chem201702302-sup-0001-SI1.pdf" }, { "basename": "nihms913583.pdf", "url": "https://authors.library.caltech.edu/records/4gh7g-8wn95/files/nihms913583.pdf" } ], "resource_type": "article", "pub_year": "2017", "author_list": "De Ruiter, Graham; Carsch, Kurtis M.; et el." }, { "id": "https://authors.library.caltech.edu/records/3g488-pcp60", "eprint_id": 79305, "eprint_status": "archive", "datestamp": "2023-08-19 04:36:21", "lastmod": "2023-10-26 14:47:30", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Carsch-Kurtis-M", "name": { "family": "Carsch", "given": "Kurtis M." }, "orcid": "0000-0003-4432-7518" }, { "id": "De-Ruiter-Graham", "name": { "family": "De Ruiter", "given": "Graham" } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Intramolecular C\u2013H and C\u2013F Bond Oxygenation by Site-Differentiated Tetranuclear Manganese Models of the OEC", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2017 American Chemical Society. \n\nReceived: April 27, 2017; Published: July 21, 2017. \n\nThis research was supported by the NIH (R01-GM102687B). T.A. is grateful for a Dreyfus fellowship. K.M.C. was a Larson Fellow and a recipient of the Caltech Summer Undergraduate Research Fellowship (SURF). We thank M. K. Takase and L. M. Henling for assistance with X-ray crystallography. \n\nThe authors declare no competing financial interest.\n\nAccepted Version - nihms913580.pdf
Supplemental Material - ic7b01022_si_001.pdf
", "abstract": "The dangler manganese center in the oxygen-evolving complex (OEC) of photosystem II plays an important role in the oxidation of water to dioxygen. Inspired by the structure of the OEC, we synthesized a series of site-differentiated tetra-manganese clusters [LMn_3(PhPz)_3OMn][OTf]_x (2: x= 2; 3: x = 1) that features an apical manganese ion\u2014distinct from the others\u2014that is appended to a trinuclear manganese core through an \u03bc4-oxygen atom bridge. This cluster design was targeted to facilitate studies of high-valent Mn-oxo formation, which is a proposed step in the mechanism for water oxidation by the OEC. Terminal Mn-oxo species\u2014supported by a multinuclear motif\u2014were targeted by treating 2 and 3 with iodosobenzene. Akin to our previously reported iron complexes, intramolecular arene hydroxylation was observed to yield the C\u2013H bond oxygenated complexes [LMn3(PhPz)_2(OArPz)OMn][OTf]x (5: x = 2; 6: x = 1). The fluorinated series [LMn_3(F_2ArPz)_3OMn][OTf]_x (8: x = 2; 9: x = 1) was also synthesized to mitigate the observed intramolecular hydroxylation. Treatment of 8 and 9 with iodosobenzene results in intramolecular arene C\u2013F bond oxygenation as judged by electrospray ionization mass spectrometry. The observed aromatic C\u2013H and C\u2013F hydroxylation is suggestive of a putative high-valent terminal metal-oxo species, and it is one of the very few examples capable of oxygenating C\u2013F bonds.", "date": "2017-08-07", "date_type": "published", "publication": "Inorganic Chemistry", "volume": "56", "number": "15", "publisher": "American Chemical Society", "pagerange": "9044-9054", "id_number": "CaltechAUTHORS:20170724-125851935", "issn": "0020-1669", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170724-125851935", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687B" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Caltech Summer Undergraduate Research Fellowship (SURF)" } ] }, "doi": "10.1021/acs.inorgchem.7b01022", "pmcid": "PMC5669799", "primary_object": { "basename": "nihms913580.pdf", "url": "https://authors.library.caltech.edu/records/3g488-pcp60/files/nihms913580.pdf" }, "related_objects": [ { "basename": "ic7b01022_si_001.pdf", "url": "https://authors.library.caltech.edu/records/3g488-pcp60/files/ic7b01022_si_001.pdf" } ], "resource_type": "article", "pub_year": "2017", "author_list": "Carsch, Kurtis M.; De Ruiter, Graham; et el." }, { "id": "https://authors.library.caltech.edu/records/d1y3h-65505", "eprint_id": 78037, "eprint_status": "archive", "datestamp": "2023-08-19 04:07:16", "lastmod": "2023-10-25 23:41:15", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Han-Zhiji", "name": { "family": "Han", "given": "Zhiji" }, "orcid": "0000-0001-9349-1571" }, { "id": "Horak-Kyle-T", "name": { "family": "Horak", "given": "Kyle T." } }, { "id": "Lee-Heui-Beom", "name": { "family": "Lee", "given": "Heui Beom" }, "orcid": "0000-0002-9550-2649" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Tetranuclear Manganese Models of the OEC Displaying Hydrogen Bonding Interactions: Application to Electrocatalytic Water Oxidation to Hydrogen Peroxide", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2017 American Chemical Society. \n\nReceived: March 27, 2017; Published: June 6, 2017. \n\nThis research was supported by the NIH (R01-GM102687A). We\nthank L. M. Henling for assistance with crystallography, J.C. Tran for assistance with the characterization of the 4-tBuC_6H_4NHPzH, and B. M. Hunter for helpful discussion on H_2O_2 detection. \n\nThe authors declare no competing financial interest.\n\nAccepted Version - jacs_2E7b03044.pdf
Accepted Version - nihms887764.pdf
Supplemental Material - ja7b03044_si_001.pdf
Supplemental Material - ja7b03044_si_002.cif
", "abstract": "Toward the development of structural and functional models of the oxygen evolving complex (OEC) of photosystem II, we report the synthesis of site-differentiated tetranuclear manganese complexes featuring three six-coordinate and one five-coordinate Mn centers. To incorporate biologically relevant second coordination sphere interactions, substituents capable of hydrogen bonding are included as pyrazolates with arylamine substituents. Complexes with terminal anionic ligands, OH\u2013 or Cl\u2013, bound to the lower coordinate metal center are supported through the hydrogen-bonding network in a fashion reminiscent of the enzymatic active site. The hydroxide complex was found to be a competent electrocatalyst for O\u2013O bond formation, a key transformation pertinent to the OEC. In an acetonitrile\u2013water mixture, at neutral pH, electrochemical water oxidation to hydrogen peroxide was observed, albeit with low (15%) Faradaic yield, likely due to competing reactions with organics. In agreement, 9,10-dihydroanthracene is electrochemically oxidized in the presence of this cluster both via H-atom abstraction and oxygenation with \u223c50% combined Faradaic yield.", "date": "2017-07-12", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "139", "number": "27", "publisher": "American Chemical Society", "pagerange": "9108-9111", "id_number": "CaltechAUTHORS:20170608-152145891", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170608-152145891", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687A" } ] }, "doi": "10.1021/jacs.7b03044", "pmcid": "PMC5643074", "primary_object": { "basename": "ja7b03044_si_001.pdf", "url": "https://authors.library.caltech.edu/records/d1y3h-65505/files/ja7b03044_si_001.pdf" }, "related_objects": [ { "basename": "ja7b03044_si_002.cif", "url": "https://authors.library.caltech.edu/records/d1y3h-65505/files/ja7b03044_si_002.cif" }, { "basename": "jacs_2E7b03044.pdf", "url": "https://authors.library.caltech.edu/records/d1y3h-65505/files/jacs_2E7b03044.pdf" }, { "basename": "nihms887764.pdf", "url": "https://authors.library.caltech.edu/records/d1y3h-65505/files/nihms887764.pdf" } ], "resource_type": "article", "pub_year": "2017", "author_list": "Han, Zhiji; Horak, Kyle T.; et el." }, { "id": "https://authors.library.caltech.edu/records/1nz2s-c0m70", "eprint_id": 77290, "eprint_status": "archive", "datestamp": "2023-08-19 03:45:15", "lastmod": "2023-10-25 22:03:09", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lee-Heui-Beom", "name": { "family": "Lee", "given": "Heui Beom" }, "orcid": "0000-0002-9550-2649" }, { "id": "Tsui-Emily-Y", "name": { "family": "Tsui", "given": "Emily Y." }, "orcid": "0000-0001-6419-3954" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "A CaMn\u2084O\u2082 model of the biological oxygen evolving complex: synthesis via cluster expansion on a low symmetry ligand", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2017 The Royal Society of Chemistry. \n\nThe article was received on 27 Mar 2017, accepted on 25 Apr 2017 and first published on 25 Apr 2017. \n\nThis work was supported by the NIH (R01-GM102687B), Caltech, a Sandia Campus Executive Fellowship (E. Y. T.) and a Dreyfus fellowship (T. A.).\n\nAccepted Version - nihms875402.pdf
Supplemental Material - c7cc02313h1_si.pdf
Supplemental Material - c7cc02313h2.cif
", "abstract": "Using a new multinucleating ligand featuring two dipyridyl alkoxide moieties and a carboxylate moiety, low symmetry tetranuclear complexes 1-M (M = Mn, Fe, and Co) have been synthesized. Complex 1-Mn was used as a precursor for the synthesis of a pentanuclear CaMn\u2084O\u2082 cluster (3) with the same metal stoichiometry as the biological OEC.", "date": "2017-06-28", "date_type": "published", "publication": "Chemical Communications", "volume": "53", "number": "51", "publisher": "Royal Society of Chemistry", "pagerange": "6832-6835", "id_number": "CaltechAUTHORS:20170509-083819492", "issn": "1359-7345", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170509-083819492", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687B" }, { "agency": "Caltech" }, { "agency": "Sandia National Laboratories" }, { "agency": "Camille and Henry Dreyfus Foundation" } ] }, "doi": "10.1039/c7cc02313h", "pmcid": "PMC5508601", "primary_object": { "basename": "c7cc02313h1_si.pdf", "url": "https://authors.library.caltech.edu/records/1nz2s-c0m70/files/c7cc02313h1_si.pdf" }, "related_objects": [ { "basename": "c7cc02313h2.cif", "url": "https://authors.library.caltech.edu/records/1nz2s-c0m70/files/c7cc02313h2.cif" }, { "basename": "nihms875402.pdf", "url": "https://authors.library.caltech.edu/records/1nz2s-c0m70/files/nihms875402.pdf" } ], "resource_type": "article", "pub_year": "2017", "author_list": "Lee, Heui Beom; Tsui, Emily Y.; et el." }, { "id": "https://authors.library.caltech.edu/records/8kr3j-xmf58", "eprint_id": 77218, "eprint_status": "archive", "datestamp": "2023-08-19 03:13:12", "lastmod": "2023-10-25 21:59:13", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Sampson-J", "name": { "family": "Sampson", "given": "Jessica" } }, { "id": "Choi-Gyeongshin", "name": { "family": "Choi", "given": "Gyeongshin" } }, { "id": "Akhtar-M-N", "name": { "family": "Akhtar", "given": "Muhammed Naseem" } }, { "id": "Jaseer-E-A", "name": { "family": "Jaseer", "given": "E. A." } }, { "id": "Theravalappil-R", "name": { "family": "Theravalappil", "given": "Rajesh" }, "orcid": "0000-0002-6022-6461" }, { "id": "Al-Muallem-H-A", "name": { "family": "Al-Muallem", "given": "Hassan Ali" } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Olefin Polymerization by Dinuclear Zirconium Catalysts Based on Rigid Teraryl Frameworks: Effects on Tacticity and Copolymerization Behavior", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2017 American Chemical Society. \n\nReceived: January 9, 2017; Published: May 4, 2017.\n\nMike Takase, Larry Henling, and Heui Beom Lee are acknowledged for crystallographic assistance. We thank Prof. Grubbs for allowing access to a GPC instrument in his laboratory at Caltech for measurements of 1-hexene homopolymers. The authors are grateful for the support provided by King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia, offered under the KFUPM-Caltech Research Collaboration. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - om7b00015_si_001.pdf
Supplemental Material - om7b00015_si_002.cif
", "abstract": "Toward gaining insight into the behavior of bimetallic catalysts for olefin polymerization, a series of structurally related binuclear zirconium catalysts with bisamine bisphenolate and pyridine bisphenolate ligands connected by rigid teraryl units were synthesized. Anthracene-9,10-diyl and 2,3,5,6-tetramethylbenzene-1,4-diyl were employed as linkers. Bulky Si^iPr_3 and SiPh_3 substituents were used in the position ortho to the phenolate oxygen. Pseudo-C_s and C_2 symmetric isomers are observed for the binuclear complexes of bisamine bisphenolate ligands. In general, binuclear catalysts show higher isotacticity compared to the monozirconium analogues, with some differences between isomers. Amine bisphenolate-supported dizirconium complexes were found to be moderately active (up to 1.5 kg mmol_(Zr)^(\u20131) h^(\u20131)) for the polymerization of 1-hexene to isotactically enriched poly-1-hexene (up to 45% mmmm) in the presence of stoichiometric trityl or anilinium borate activators. Moderate activity was observed for the production of isotactically enriched polypropylene (up to 2.8 kg mmol_(Zr)^(\u20131) h^(\u20131) and up to 25.4% mmmm). The previously proposed model for tacticity control based on distal steric effects from the second metal site is consistent with the observed behavior. Both bisamine bisphenolate and pyridine bisphenolate supported complexes are active for the production of polyethylene in the presence of MAO with activities in the range of 1.1\u20131.6 kg mmol_(Zr)^(\u20131) h^(\u20131) and copolymerize ethylene with \u03b1-olefins. Little difference in the level of \u03b1-olefin incorporation is observed between mono- and dinuclear catalysts supported with the pyridine bisphenolate catalysts. In contrast, the size of the olefin affects the level of incorporation differently between monometallic and bimetallic catalysts for the bisamine bisphenolate system. The ratio of the incorporation levels with dinuclear vs mononuclear catalysts decreases with increasing comonomer size. This effect is attributed to steric pressure provided by the distal metal center on the larger olefin in dinuclear catalysts.", "date": "2017-05-22", "date_type": "published", "publication": "Organometallics", "volume": "36", "number": "10", "publisher": "American Chemical Society", "pagerange": "1915-1928", "id_number": "CaltechAUTHORS:20170505-103003742", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170505-103003742", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "King Fahd University of Petroleum and Minerals (KFUPM)" } ] }, "doi": "10.1021/acs.organomet.7b00015", "primary_object": { "basename": "om7b00015_si_001.pdf", "url": "https://authors.library.caltech.edu/records/8kr3j-xmf58/files/om7b00015_si_001.pdf" }, "related_objects": [ { "basename": "om7b00015_si_002.cif", "url": "https://authors.library.caltech.edu/records/8kr3j-xmf58/files/om7b00015_si_002.cif" } ], "resource_type": "article", "pub_year": "2017", "author_list": "Sampson, Jessica; Choi, Gyeongshin; et el." }, { "id": "https://authors.library.caltech.edu/records/wvr9z-0y617", "eprint_id": 76562, "eprint_status": "archive", "datestamp": "2023-08-19 02:42:54", "lastmod": "2023-10-25 16:07:13", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lifschitz-A-M", "name": { "family": "Lifschitz", "given": "Alejo M." } }, { "id": "Hirscher-N-A", "name": { "family": "Hirscher", "given": "Nathanael A." } }, { "id": "Lee-Heui-Beom", "name": { "family": "Lee", "given": "Heui Beom" }, "orcid": "0000-0002-9550-2649" }, { "id": "Buss-J-A", "name": { "family": "Buss", "given": "Joshua A." }, "orcid": "0000-0002-3347-8583" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Ethylene Tetramerization Catalysis: Effects of Aluminum-Induced Isomerization of PNP to PPN Ligands", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2017 American Chemical Society. \n\nReceived 10 March 2017. Published online 13 April 2017. \n\nWe are grateful to The Dow Chemical Company and Caltech for funding. T.A. .is grateful for Sloan, Dreyfus, and Cottrell fellowships. J.A.B. is grateful to the NSF for a Graduate Research Fellowship. We thank Michael K. Takase and Lawrence M. Henling for assistance with crystallography, and Sean Ewart, David Laitar, and Mari Rosen for insightful discussions.\n\nSupplemental Material - om7b00189_si_001.pdf
Supplemental Material - om7b00189_si_002.xyz
Supplemental Material - om7b00189_si_003.cif
", "abstract": "Diphosphinoamines (PNP) are commonly used to support Cr-catalyzed ethylene trimerization and tetramerization. Although isomerization of PNP to a PPN (iminobisphosphine) species has been established, such reactivity has not been studied in detail in the context of Cr-based selective ethylene oligomerization catalysis. Herein, we show that precursors that are stable as PNP frameworks can isomerize to PPN species in the presence of chlorinated aluminum activators relevant to ethylene oligomerization catalysis. Isomerization changes the pattern of reactivity of the ligands, making them more susceptible to nucleophilic attack by alkyl groups, resulting in a variety of degradation products. The isomerization-mediated degradation of PNP ligands leads to the formation of unwanted polymerization catalysts in ethylene tetramerization systems, thus providing insight into the formation of Cr species that affect the overall selectivity and activity values. For example, independently prepared [R_2PNR]^\u2014 leads to potent Cr polymerization catalysts. The susceptibility for isomerization is dependent on the nature of the N-substituent of the PNP precursor. Electron donating N-substituent i-Pr, which disfavors the PPN isomer compared to p-tolyl, and minimization of water contamination correlate with higher oligomerization activity and lower polymer byproducts. More broadly, the present study demonstrates the significant impact that Al-activators can have on the structure and behavior of the supporting ligand leading to detrimental reactivity.", "date": "2017-04-24", "date_type": "published", "publication": "Organometallics", "volume": "36", "number": "8", "publisher": "American Chemical Society", "pagerange": "1640-1648", "id_number": "CaltechAUTHORS:20170414-070035593", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170414-070035593", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" }, { "agency": "Caltech" }, { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Cottrell Scholar of Research Corporation" }, { "agency": "NSF Graduate Research Fellowship" } ] }, "doi": "10.1021/acs.organomet.7b00189", "primary_object": { "basename": "om7b00189_si_001.pdf", "url": "https://authors.library.caltech.edu/records/wvr9z-0y617/files/om7b00189_si_001.pdf" }, "related_objects": [ { "basename": "om7b00189_si_002.xyz", "url": "https://authors.library.caltech.edu/records/wvr9z-0y617/files/om7b00189_si_002.xyz" }, { "basename": "om7b00189_si_003.cif", "url": "https://authors.library.caltech.edu/records/wvr9z-0y617/files/om7b00189_si_003.cif" } ], "resource_type": "article", "pub_year": "2017", "author_list": "Lifschitz, Alejo M.; Hirscher, Nathanael A.; et el." }, { "id": "https://authors.library.caltech.edu/records/40a5p-0dk83", "eprint_id": 75394, "eprint_status": "archive", "datestamp": "2023-08-21 20:51:17", "lastmod": "2023-10-25 15:00:44", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "De-Ruiter-Graham", "name": { "family": "De Ruiter", "given": "Graham" } }, { "id": "Carsch-Kurtis-M", "name": { "family": "Carsch", "given": "Kurtis M." }, "orcid": "0000-0003-4432-7518" }, { "id": "Gul-Sheraz", "name": { "family": "Gul", "given": "Sheraz" }, "orcid": "0000-0001-8920-8737" }, { "id": "Chatterjee-Ruchira", "name": { "family": "Chatterjee", "given": "Ruchira" }, "orcid": "0000-0002-0865-061X" }, { "id": "Thompson-Niklas-B", "name": { "family": "Thompson", "given": "Niklas B." }, "orcid": "0000-0003-2745-4945" }, { "id": "Takase-Michael-K", "name": { "family": "Takase", "given": "Michael K." }, "orcid": "0000-0001-8365-3645" }, { "id": "Yano-Junko", "name": { "family": "Yano", "given": "Junko" }, "orcid": "0000-0001-6308-9071" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Accelerated Oxygen Atom Transfer and C\u2212H Bond Oxygenation by Remote Redox Changes in Fe_3Mn-Iodosobenzene Adducts", "ispublished": "pub", "full_text_status": "public", "keywords": "C\u2212H bond oxygenation; clusters; iodosobenzene adduct; multimetallic complexes; oxygen atom transfer", "note": "\u00a9 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. \n\nVersion of record online: 24 March 2017; Manuscript Received: 6 February 2017. \n\nThis research was supported by the NIH (R01-GM102687B).\nT.A. is grateful for Dreyfus and Cottrell fellowships. K.M.C is grateful for a Summer Undergraduate Research Fellowship. We thank Lawrence M. Henling for assistance with X-ray crystallography. Part of this research (XAS data collection) was carried out on beamline 7-3 at the SSRL, operated by Stanford University for the US DOE Office of Science, and supported by the DOE and NIH. XAS studies were performed with support of the Office of Science, OBES, Division of Chemical Sciences, Geosciences, and Biosciences (CSGB) of the DOE under contract no. DE-AC02-05CH11231 (J.Y.).\n\nAccepted Version - nihms868555.pdf
Supplemental Material - ange201701319-sup-0001-misc_information.pdf
", "abstract": "We report the synthesis, characterization, and reactivity of [Lfe_3(PhPz)_3OMn(^sPhIO)][OTf]_x (3: x=2; 4: x=3), where 4 is one of very few examples of iodosobenzene\u2013metal adducts characterized by X-ray crystallography. Access to these rare heterometallic clusters enabled differentiation of the metal centers involved in oxygen atom transfer (Mn) or redox modulation (Fe). Specifically, ^(57)Fe M\u00f6ssbauer and X-ray absorption spectroscopy provided unique insights into how changes in oxidation state (Fe^(III)_2Fe^(II)Mn^(II) vs. Fe^(III)_3Mn^(II)) influence oxygen atom transfer in tetranuclear Fe_3Mn clusters. In particular, a one-electron redox change at a distal metal site leads to a change in oxygen atom transfer reactivity by ca. two orders of magnitude.", "date": "2017-04-18", "date_type": "published", "publication": "Angewandte Chemie International Edition", "volume": "56", "number": "17", "publisher": "Wiley", "pagerange": "4772-4776", "id_number": "CaltechAUTHORS:20170324-141105678", "issn": "1433-7851", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170324-141105678", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687B" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Cottrell Scholar of Research Corporation" }, { "agency": "Caltech Summer Undergraduate Research Fellowship (SURF)" }, { "agency": "Department of Energy (DOE)", "grant_number": "DEAC02-05CH11231" } ] }, "doi": "10.1002/anie.201701319", "pmcid": "PMC5505263", "primary_object": { "basename": "ange201701319-sup-0001-misc_information.pdf", "url": "https://authors.library.caltech.edu/records/40a5p-0dk83/files/ange201701319-sup-0001-misc_information.pdf" }, "related_objects": [ { "basename": "nihms868555.pdf", "url": "https://authors.library.caltech.edu/records/40a5p-0dk83/files/nihms868555.pdf" } ], "resource_type": "article", "pub_year": "2017", "author_list": "De Ruiter, Graham; Carsch, Kurtis M.; et el." }, { "id": "https://authors.library.caltech.edu/records/p87ym-2g985", "eprint_id": 72691, "eprint_status": "archive", "datestamp": "2023-08-19 00:58:57", "lastmod": "2023-10-23 22:51:07", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Jung-Suho", "name": { "family": "Jung", "given": "Suho" }, "orcid": "0000-0002-8119-3902" }, { "id": "Kortlever-R", "name": { "family": "Kortlever", "given": "Ruud" } }, { "id": "Jones-R-J-R", "name": { "family": "Jones", "given": "Ryan J. R." }, "orcid": "0000-0002-4629-3115" }, { "id": "Lichterman-Michael-Frankston-Yang", "name": { "family": "Lichterman", "given": "Michael F." }, "orcid": "0000-0002-0710-7068" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "McCrory-C-C-L", "name": { "family": "McCrory", "given": "Charles C. L." }, "orcid": "0000-0001-9039-7192" }, { "id": "Peters-J-C", "name": { "family": "Peters", "given": "Jonas C." }, "orcid": "0000-0002-6610-4414" } ] }, "title": "Gastight Hydrodynamic Electrochemistry: Design for a Hermetically Sealed Rotating Disk Electrode Cell", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2016 American Chemical Society. \n\nReceived: October 28, 2016; Accepted: December 7, 2016; Published: December 7, 2016. \n\nThis material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993. \n\nThe authors declare no competing financial interest.\n\nAccepted Version - acs_2Eanalchem_2E6b04228.pdf
", "abstract": "Rotating disk electrodes (RDEs) are widely used in electrochemical characterization to analyze the mechanisms of various electrocatalytic reactions. RDE experiments often make use of or require collection and quantification of gaseous products. The combination of rotating parts and gaseous analytes makes the design of RDE cells that allow for headspace analysis challenging due to gas leaks at the interface of the cell body and the rotator. In this manuscript we describe a new, hermetically-sealed electrochemical cell that allows for electrode rotation while simultaneously providing a gastight environment. Electrode rotation in this new cell design is controlled by magnetically coupling the working electrode to a rotating magnetic driver. Calibration of the RDE using a tachometer shows that the rotation speed of the electrode is the same as that of the magnetic driver. To validate the performance of this cell for hydrodynamic measurements, limiting currents from the reduction of a potassium ferrocyanide (K_4[Fe(CN)_6] \u20223H_2O) were measured and shown to compare favorably with calculated values from the Levich equation and with data obtained using more typical, non-gastight RDE cells. Faradaic efficiencies of ~95% were measured in the gas phase for oxygen evolution in alkaline media at an Inconel 625 alloy electrocatalyst during rotation at 1600 rpm. These data verify that a gastight environment is maintained even during rotation.", "date": "2017-01-03", "date_type": "published", "publication": "Analytical Chemistry", "volume": "89", "number": "1", "publisher": "American Chemical Society", "pagerange": "581-585", "id_number": "CaltechAUTHORS:20161209-102641774", "issn": "0003-2700", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161209-102641774", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0004993" } ] }, "local_group": { "items": [ { "id": "JCAP" } ] }, "doi": "10.1021/acs.analchem.6b04228", "primary_object": { "basename": "acs_2Eanalchem_2E6b04228.pdf", "url": "https://authors.library.caltech.edu/records/p87ym-2g985/files/acs_2Eanalchem_2E6b04228.pdf" }, "resource_type": "article", "pub_year": "2017", "author_list": "Jung, Suho; Kortlever, Ruud; et el." }, { "id": "https://authors.library.caltech.edu/records/4bzbz-h0t08", "eprint_id": 72922, "eprint_status": "archive", "datestamp": "2023-08-19 00:37:22", "lastmod": "2023-10-23 23:24:24", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Buss-J-A", "name": { "family": "Buss", "given": "Joshua A." }, "orcid": "0000-0002-3347-8583" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Mechanism of Molybdenum-Mediated Carbon Monoxide Deoxygenation and Coupling: Mono- and Dicarbyne Complexes Precede C\u2013O Bond Cleavage and C\u2013C Bond Formation", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2016 American Chemical Society. \n\nReceived: October 7, 2016; Published: November 21, 2016. \n\nWe thank Larry Henling and Mike Takase for invaluable crystallographic assistance and David VanderVelde for NMR expertise. We are grateful to Jay Labinger for insightful suggestions regarding the synthesis of mixed molybdenum dicarbyne complexes. Sibo Lin is thanked for advice and discussions regarding the computations. T.A. is grateful for Sloan and Dreyfus fellowships and J.A.B. for a NSF graduate research fellowship. This research was funded by the NSF (CHE-1151918) and Caltech. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ja6b10535_si_001.cif
Supplemental Material - ja6b10535_si_002.pdf
", "abstract": "Deoxygenative coupling of CO to value-added C_(\u22652) products is challenging and mechanistically poorly understood. Herein, we report a mechanistic investigation into the reductive coupling of CO, which provides new fundamental insights into a multielectron bond-breaking and bond-making transformation. In our studies, the formation of a bis(siloxycarbyne) complex precedes C\u2013O bond cleavage. At \u221278 \u00b0C, over days, C\u2013C coupling occurs without C\u2013O cleavage. However, upon warming to 0 \u00b0C, C\u2013O cleavage is observed from this bis(siloxycarbyne) complex. A siloxycarbyne/CO species undergoes C\u2013O bond cleavage at lower temperatures, indicating that monosilylation, and a more electron-rich Mo center, favors deoxygenative pathways. From the bis(siloxycarbyne), isotopic labeling experiments and kinetics are consistent with a mechanism involving unimolecular silyl loss or C\u2013O cleavage as rate-determining steps toward carbide formation. Reduction of Mo(IV) CO adducts of carbide and silylcarbyne species allowed for the spectroscopic detection of reduced silylcarbyne/CO and mixed silylcarbyne/siloxycarbyne complexes, respectively. Upon warming, both of these silylcarbynes undergo C\u2013C bond formation, releasing silylated C_2O_1 fragments and demonstrating that the multiple bonded terminal Mo\u2261C moiety is an intermediate on the path to deoxygenated, C\u2013C coupled products. The electronic structures of Mo carbide and carbyne species were investigated quantum mechanically. Overall, the present studies establish the elementary reactions steps by which CO is cleaved and coupled at a single metal site.", "date": "2016-12-21", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "138", "number": "50", "publisher": "American Chemical Society", "pagerange": "16466-16477", "id_number": "CaltechAUTHORS:20161219-075245925", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161219-075245925", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "Caltech" } ] }, "doi": "10.1021/jacs.6b10535", "primary_object": { "basename": "ja6b10535_si_001.cif", "url": "https://authors.library.caltech.edu/records/4bzbz-h0t08/files/ja6b10535_si_001.cif" }, "related_objects": [ { "basename": "ja6b10535_si_002.pdf", "url": "https://authors.library.caltech.edu/records/4bzbz-h0t08/files/ja6b10535_si_002.pdf" } ], "resource_type": "article", "pub_year": "2016", "author_list": "Buss, Joshua A. and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/bhyds-tae98", "eprint_id": 71203, "eprint_status": "archive", "datestamp": "2023-08-22 19:09:04", "lastmod": "2023-10-23 15:29:00", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kelley-P", "name": { "family": "Kelley", "given": "Paul" } }, { "id": "Edouard-G-A", "name": { "family": "Edouard", "given": "Guy A." } }, { "id": "Lin-Sibo", "name": { "family": "Lin", "given": "Sibo" }, "orcid": "0000-0001-5922-6694" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Lewis Acid Accelerated Aryl Ether Bond Cleavage with Nickel: Orders of Magnitude Rate Enhancement Using AlMe_3", "ispublished": "pub", "full_text_status": "public", "keywords": "aryl ether cleavage; cross coupling; Lewis acid; nickel; rate acceleration", "note": "\u00a9 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. \n\nVersion of record online: 18 October 2016; Accepted manuscript online: 26 September 2016; Manuscript Received: 2 September 2016. \n\nWe are grateful to Caltech, NSF (CHE-1151918), and BP for funding. T.A. is grateful for a Dreyfus fellowship. P.K. thanks UNCF/Merck for a Graduate Science Research Dissertation Fellowship.\n\nSupplemental Material - chem201604160-sup-0001-misc_information.pdf
", "abstract": "Study of the kinetics of intramolecular aryl ether C\u2212O bond cleavage by Ni was facilitated by access to a family of metal complexes supported by diphosphines with pendant aryl-methyl ethers. The nature of the aryl substituents was found to have little effect on the rate of cleavage. In contrast, soluble Lewis acidic additives accelerate the aryl ether cleavage dramatically. The effect of AlMe3 was studied in detail, and showed an increase in rate by several orders of magnitude. Low temperature NMR spectroscopy studies demonstrate quantitative coordination of ether to Al. From the Lewis acid-bound precursor, the activation parameters for ether cleavage are significantly lower. These findings provide a mechanistic basis for milder catalyst design for the activation of strong bonds.", "date": "2016-11-21", "date_type": "published", "publication": "Chemistry: a European Journal", "volume": "22", "number": "48", "publisher": "John Wiley & Sons", "pagerange": "17173-17176", "id_number": "CaltechAUTHORS:20161018-082139944", "issn": "0947-6539", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161018-082139944", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "BP" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "UNCF/Merck" } ] }, "doi": "10.1002/chem.201604160", "primary_object": { "basename": "chem201604160-sup-0001-misc_information.pdf", "url": "https://authors.library.caltech.edu/records/bhyds-tae98/files/chem201604160-sup-0001-misc_information.pdf" }, "resource_type": "article", "pub_year": "2016", "author_list": "Kelley, Paul; Edouard, Guy A.; et el." }, { "id": "https://authors.library.caltech.edu/records/6d3ft-tws73", "eprint_id": 67881, "eprint_status": "archive", "datestamp": "2023-08-20 12:25:13", "lastmod": "2023-10-19 22:02:21", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lin-Po-Heng", "name": { "family": "Lin", "given": "Po-Heng" }, "orcid": "0000-0002-0893-0806" }, { "id": "Tsui-Emily-Y", "name": { "family": "Tsui", "given": "Emily Y." }, "orcid": "0000-0001-6419-3954" }, { "id": "Habib-Fatemah", "name": { "family": "Habib", "given": "Fatemah" } }, { "id": "Murugesu-Muralee", "name": { "family": "Murugesu", "given": "Muralee" }, "orcid": "0000-0002-5123-374X" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Effect of the Mn Oxidation State on Single-Molecule-Magnet Properties: Mn\u1d35\u1d35\u1d35 vs Mn\u1d35\u2c7d in Biologically Inspired DyMn\u2083O\u2084 Cubanes", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2016 American Chemical Society. \n\nReceived: March 15, 2016. Publication Date (Web): June 9, 2016. \n\nWe thank Caltech, the NIH (Grant R01 GM102687A), and a Sandia Campus Executive Fellowship (to E.Y.T.) for financial support. T.A. is grateful for Sloan, Cottrell, and Dreyfus scholarships. We also thank R. Holmberg for Magellan analysis. \n\nThe authors declare no competing financial interest.\n\nAccepted Version - nihms868559.pdf
Supplemental Material - ic6b00630_si_001.cif
Supplemental Material - ic6b00630_si_002.cif
Supplemental Material - ic6b00630_si_003.cif
Supplemental Material - ic6b00630_si_004.pdf
", "abstract": "Inspired by the ferromagnetic coupling in the cubane model CaMn\u1d35\u2c7d\u2083O\u2084 of the oxygen-evolving complex of photosystem II, 3d\u20134f mixed-metal DyMn\u2083O\u2084 clusters were prepared for investigation of the magnetic properties. For comparison, YMn\u1d35\u2c7d\u2083O\u2084 and YMn\u1d35\u2c7d\u2082Mn\u1d35\u1d35\u1d35O\u2084 clusters were investigated as well and showed ferromagnetic interactions, like the calcium analogue. DyMn\u1d35\u2c7d\u2083O\u2084 displays single-molecule-magnet properties, while the one-electron-reduced species (DyMn\u1d35\u2c7d\u2082Mn\u1d35\u1d35\u1d35O\u2084) does not, despite the presence of a Mn\u1d35\u1d35\u1d35 center with higher spin and single-ion anisotropy.", "date": "2016-06-20", "date_type": "published", "publication": "Inorganic Chemistry", "volume": "55", "number": "12", "publisher": "American Chemical Society", "pagerange": "6095-6099", "id_number": "CaltechAUTHORS:20160613-131348637", "issn": "0020-1669", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160613-131348637", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "NIH", "grant_number": "R01 GM102687A" }, { "agency": "Sandia National Laboratories" }, { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Cottrell Scholar of Research Corporation" }, { "agency": "Camille and Henry Dreyfus Foundation" } ] }, "doi": "10.1021/acs.inorgchem.6b00630", "pmcid": "PMC5510600", "primary_object": { "basename": "ic6b00630_si_003.cif", "url": "https://authors.library.caltech.edu/records/6d3ft-tws73/files/ic6b00630_si_003.cif" }, "related_objects": [ { "basename": "ic6b00630_si_004.pdf", "url": "https://authors.library.caltech.edu/records/6d3ft-tws73/files/ic6b00630_si_004.pdf" }, { "basename": "nihms868559.pdf", "url": "https://authors.library.caltech.edu/records/6d3ft-tws73/files/nihms868559.pdf" }, { "basename": "ic6b00630_si_001.cif", "url": "https://authors.library.caltech.edu/records/6d3ft-tws73/files/ic6b00630_si_001.cif" }, { "basename": "ic6b00630_si_002.cif", "url": "https://authors.library.caltech.edu/records/6d3ft-tws73/files/ic6b00630_si_002.cif" } ], "resource_type": "article", "pub_year": "2016", "author_list": "Lin, Po-Heng; Tsui, Emily Y.; et el." }, { "id": "https://authors.library.caltech.edu/records/ct0mc-82n52", "eprint_id": 67553, "eprint_status": "archive", "datestamp": "2023-08-20 12:05:17", "lastmod": "2023-10-18 21:17:09", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Henthorn-J-T", "name": { "family": "Henthorn", "given": "Justin T." }, "orcid": "0000-0003-4876-2680" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Modulation of Proton-Coupled Electron Transfer through Molybdenum\u2013Quinonoid Interactions", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2016 American Chemical Society. \n\nReceived: February 8, 2016. Publication Date (Web): May 26, 2016. \n\nWe thank Lawrence M. Henling and Dr. Michael Takase for crystallographic assistance and Choon Heng (Marcus) Low for synthesizing quinone 11 and for performing some of the control experiments. We thank Caltech and the NSF (CHE-1151918, T.A., and NSF GRFP, J.T.H.) for funding. T.A. is grateful for Sloan, Cottrell, and Dreyfus fellowships. The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF CRIF:MU award to Caltech, CHE-0639094. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ic6b00331_si_001.cif
Supplemental Material - ic6b00331_si_002.pdf
", "abstract": "An expanded series of \u03c0-bound molybdenum\u2013quinonoid complexes supported by pendant phosphines has been synthesized. These compounds formally span three protonation\u2013oxidation states of the quinonoid fragment (catechol, semiquinone, quinone) and two different oxidation states of the metal (Mo^0, Mo^(II)), notably demonstrating a total of two protons and four electrons accessible in the system. Previously, the reduced Mo^0\u2013catechol complex 1 and its reaction with dioxygen to yield the two-proton/two-electron oxidized Mo^0\u2013quinone compound 4 was explored, while, herein, the expansion of the series to include the two-electron oxidized Mo^(II)\u2013catechol complex 2, the one-proton/two-electron oxidized Mo\u2013semiquinone complex 3, and the two-proton/four-electron oxidized MoII\u2013quinone complexes 5 and 6 is reported. Transfer of multiple equivalents of protons and electrons from the Mo^0 and Mo^(II) catechol complexes, 1 and 2, to H atom acceptor TEMPO suggests the presence of weak O\u2013H bonds. Although thermochemical analyses are hindered by the irreversibility of the electrochemistry of the present compounds, the reactivity observed suggests weaker O\u2013H bonds compared to the free catechol, indicating that proton-coupled electron transfer can be facilitated significantly by the \u03c0-bound metal center.", "date": "2016-06-06", "date_type": "published", "publication": "Inorganic Chemistry", "volume": "55", "number": "11", "publisher": "American Chemical Society", "pagerange": "5337-5342", "id_number": "CaltechAUTHORS:20160601-143209378", "issn": "0020-1669", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160601-143209378", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Cottrell Scholar of Research Corporation" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "NSF", "grant_number": "CHE-0639094" } ] }, "doi": "10.1021/acs.inorgchem.6b00331", "primary_object": { "basename": "ic6b00331_si_001.cif", "url": "https://authors.library.caltech.edu/records/ct0mc-82n52/files/ic6b00331_si_001.cif" }, "related_objects": [ { "basename": "ic6b00331_si_002.pdf", "url": "https://authors.library.caltech.edu/records/ct0mc-82n52/files/ic6b00331_si_002.pdf" } ], "resource_type": "article", "pub_year": "2016", "author_list": "Henthorn, Justin T. and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/6h3c7-yk451", "eprint_id": 66239, "eprint_status": "archive", "datestamp": "2023-08-20 11:20:35", "lastmod": "2023-10-18 17:17:44", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lionetti-D", "name": { "family": "Lionetti", "given": "Davide" }, "orcid": "0000-0002-4937-886X" }, { "id": "De-Ruiter-G", "name": { "family": "De Ruiter", "given": "Graham" } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "A trans-Hyponitrite Intermediate in the Reductive Coupling and Deoxygenation of Nitric Oxide by a Tricopper\u2013Lewis Acid Complex", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2016 American Chemical Society. \n\nReceived: January 29, 2016; Publication Date (Web): March 30, 2016. \n\nThis work was supported by Caltech and the PRF (T.A.). T.A. is grateful for Sloan, Dreyfus, and Cottrell fellowships. We thank Dr. Michael K. Takase and Lawrence M. Henling for assistance with X-ray crystallography. We thank Professor Jonas C. Peters for use of two infrared spectrometers. D.L. gratefully acknowledges a graduate fellowship from the Resnick Sustainability Institute at Caltech. The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF Chemistry Research Instrumentation award to Caltech (CHE-0639094). \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ja6b01083_si_001.cif
Supplemental Material - ja6b01083_si_002.cif
Supplemental Material - ja6b01083_si_003.pdf
", "abstract": "The reduction of nitric oxide (NO) to nitrous oxide (N_2O) is a process relevant to biological chemistry as well as to the abatement of certain environmental pollutants. One of the proposed key intermediates in NO reduction is hyponitrite (N_2O_2^(2\u2013)), the product of reductive coupling of two NO molecules. We report the reductive coupling of NO by an yttrium\u2013tricopper complex generating a trans-hyponitrite moiety supported by two \u03bc-O-bimetallic (Y,Cu) cores, a previously unreported coordination mode. Reaction of the hyponitrite species with Br\u00f8nsted acids leads to the generation of N_2O, demonstrating the viability of the hyponitrite complex as an intermediate in NO reduction to N_2O. The additional reducing equivalents stored in each tricopper unit are employed in a subsequent step for N_2O reduction to N_2, for an overall (partial) conversion of NO to N_2. The combination of Lewis acid and multiple redox active metals facilitates this four electron conversion via an isolable hyponitrite intermediate.", "date": "2016-04-20", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "138", "number": "15", "publisher": "American Chemical Society", "pagerange": "5008-5011", "id_number": "CaltechAUTHORS:20160418-101830823", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160418-101830823", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "American Chemical Society Petroleum Research Fund" }, { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Cottrell Scholar of Research Corporation" }, { "agency": "Resnick Sustainability Institute" }, { "agency": "NSF", "grant_number": "CHE-0639094" } ] }, "local_group": { "items": [ { "id": "Resnick-Sustainability-Institute" } ] }, "doi": "10.1021/jacs.6b01083", "primary_object": { "basename": "ja6b01083_si_001.cif", "url": "https://authors.library.caltech.edu/records/6h3c7-yk451/files/ja6b01083_si_001.cif" }, "related_objects": [ { "basename": "ja6b01083_si_002.cif", "url": "https://authors.library.caltech.edu/records/6h3c7-yk451/files/ja6b01083_si_002.cif" }, { "basename": "ja6b01083_si_003.pdf", "url": "https://authors.library.caltech.edu/records/6h3c7-yk451/files/ja6b01083_si_003.pdf" } ], "resource_type": "article", "pub_year": "2016", "author_list": "Lionetti, Davide; De Ruiter, Graham; et el." }, { "id": "https://authors.library.caltech.edu/records/1awp4-ewj36", "eprint_id": 65357, "eprint_status": "archive", "datestamp": "2023-08-20 10:55:24", "lastmod": "2023-10-18 14:34:29", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Horak-K-T", "name": { "family": "Horak", "given": "Kyle T." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Dioxygen Reduction by a Pd(0)\u2013Hydroquinone Diphosphine Complex", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2016 American Chemical Society. \n\nReceived: December 10, 2015; Publication Date (Web): March 7, 2016. \n\nWe thank Lawrence M. Henling and Mike Takase for crystallographic assistance. We thank Caltech and NSF (CHE-1151918) for funding. T.A. is grateful for Sloan, Cottrell, and Dreyfus fellowships. The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF CRIF:MU award to Caltech, CHE0639094. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ja5b12928_si_001.txt
Supplemental Material - ja5b12928_si_002.pdf
", "abstract": "A novel p-terphenyl diphosphine ligand was synthesized with a noninnocent hydroquinone moiety as the central arene (1-H). Pseudo-tetrahedral 4-coordinate Ni^0 and Pd^0\u2013quinone (2 and 3, respectively) complexes proved accessible by metalating 1-H with the corresponding M(OAc)_2 precursors. O_2 does not react with the Pd^0\u2013quinone species (3) and protonation occurs at the quinone moiety indicating that the coordinated oxidized quinonoid moiety prevents reactivity at the metal. A 2-coordinate Pd^0\u2013hydroquinone complex (4-H) was prepared using a one-pot metalation with Pd^(II) followed by reduction. The reduced quinonoid moiety in 4-H shows metal-coupled reactivity with small molecules. 4-H was capable of reducing a variety of substrates including dioxygen, nitric oxide, nitrous oxide, 1-azido adamantane, trimethylamine n-oxide, and 1,4-benzoquinone quantitatively producing 3 as the Pd-containing reaction product. Mechanistic investigations of dioxygen reduction revealed that the reaction proceeds through a \u03b7^2-peroxo intermediate (Int1) at low temperatures followed by subsequent ligand oxidation at higher temperatures in a reaction that consumed half an equivalent of O_2 and produced water as a final oxygenic byproduct. Control compounds with methyl protected phenolic moieties (4-Me), displaying a Ag^I center incapable of O_2 binding (7-H) or a cationic Pd\u2013H motif (6-H) allowed for the independent examination of potential reaction pathways. The reaction of 4-Me with dioxygen at low temperature produces a species (8-Me) analogous to Int1 demonstrating that initial dioxygen activation is an inner sphere Pd-based process where the hydroquinone moiety only subsequently participates in the reduction of O_2, at higher temperatures, by H^+/e^\u2013 transfers.", "date": "2016-03-16", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "138", "number": "10", "publisher": "American Chemical Society", "pagerange": "3443-3452", "id_number": "CaltechAUTHORS:20160315-101431160", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160315-101431160", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Cottrell Scholar of Research Corporation" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "NSF", "grant_number": "CHE-0639094" } ] }, "doi": "10.1021/jacs.5b12928", "primary_object": { "basename": "ja5b12928_si_002.pdf", "url": "https://authors.library.caltech.edu/records/1awp4-ewj36/files/ja5b12928_si_002.pdf" }, "related_objects": [ { "basename": "ja5b12928_si_001.txt", "url": "https://authors.library.caltech.edu/records/1awp4-ewj36/files/ja5b12928_si_001.txt" } ], "resource_type": "article", "pub_year": "2016", "author_list": "Horak, Kyle T. and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/rfdtt-1m859", "eprint_id": 64298, "eprint_status": "archive", "datestamp": "2023-08-20 10:15:04", "lastmod": "2023-10-17 20:49:16", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "De-Ruiter-Graham", "name": { "family": "De Ruiter", "given": "Graham" }, "orcid": "0000-0001-6008-286X" }, { "id": "Thompson-Niklas-B", "name": { "family": "Thompson", "given": "Niklas B." }, "orcid": "0000-0003-2745-4945" }, { "id": "Takase-Michael-K", "name": { "family": "Takase", "given": "Michael K." }, "orcid": "0000-0001-8365-3645" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Intramolecular C\u2013H and C\u2013F Bond Oxygenation Mediated by a Putative Terminal Oxo Species in Tetranuclear Iron Complexes", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2016 American Chemical Society. \n\nReceived: November 22, 2015. Article ASAP. Publication Date (Web): January 13, 2016. \n\nThis research was supported by the NIH (R01-GM102687A). T.A. is grateful for Sloan, Dreyfus, and Cottrell fellowships. T.A. and G. de R. are grateful for a Camille & Henry Dreyfus Environmental Chemistry Fellowship. We thank Lawrence M. Henling for assistance with crystallography. \n\nThe authors declare no competing financial interest.\n\nAccepted Version - nihms786209.pdf
Supplemental Material - ja5b12214_si_001.cif
Supplemental Material - ja5b12214_si_002.pdf
", "abstract": "Herein we report the intramolecular arene C\u2013H and C\u2013F bond oxygenation by tetranuclear iron complexes. Treatment of [LFe_3(PhPz)_3OFe][OTf]_2 (1) or its fluorinated analog [LFe_3(F2ArPz)_3OFe][OTf]_2 (5) with iodosobenzene results in the regioselective hydroxylation of a bridging pyrazolate ligand, converting a C\u2013H or C\u2013F bond into a C\u2013O bond. The observed reactivity suggests the formation of terminal and reactive Fe-oxo intermediates. With the possibility of intramolecular electron transfer within clusters in 1 and 5, different reaction pathways (Fe^(IV)-oxo vs Fe^(III)-oxo) might be responsible for the observed arene hydroxylation.", "date": "2016-02-10", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "138", "number": "5", "publisher": "American Chemical Society", "pagerange": "1486-1489", "id_number": "CaltechAUTHORS:20160208-092710615", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160208-092710615", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687A" }, { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Cottrell Scholar of Research Corporation" } ] }, "doi": "10.1021/jacs.5b12214", "pmcid": "PMC4871154", "primary_object": { "basename": "nihms786209.pdf", "url": "https://authors.library.caltech.edu/records/rfdtt-1m859/files/nihms786209.pdf" }, "related_objects": [ { "basename": "ja5b12214_si_001.cif", "url": "https://authors.library.caltech.edu/records/rfdtt-1m859/files/ja5b12214_si_001.cif" }, { "basename": "ja5b12214_si_002.pdf", "url": "https://authors.library.caltech.edu/records/rfdtt-1m859/files/ja5b12214_si_002.pdf" } ], "resource_type": "article", "pub_year": "2016", "author_list": "De Ruiter, Graham; Thompson, Niklas B.; et el." }, { "id": "https://authors.library.caltech.edu/records/yfzjz-5a630", "eprint_id": 63155, "eprint_status": "archive", "datestamp": "2023-08-20 09:52:27", "lastmod": "2023-10-25 23:36:01", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Buss-J-A", "name": { "family": "Buss", "given": "Joshua A." }, "orcid": "0000-0002-3347-8583" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Four-electron deoxygenative reductive coupling of carbon monoxide at a single metal site", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2015 Macmillan Publishers Limited. \n\nReceived 17 July; accepted 6 October 2015. Published online 21 December 2015. \n\nWe thank L. M. Henling and M. K. Takase for crystallographic assistance and D. VanderVelde for NMR expertise. We are grateful to Caltech and the National Science Foundation (grant CHE-1151918 to T.A., and GRFP to J.A.B.) for funding. \n\nContributions: J.A.B. and T.A. designed the research. J.A.B. conducted the experiments. J.A.B. and T.A. interpreted the data and wrote the manuscript. \n\nThe authors declare no competing financial interests. \n\nX-ray crystallographic coordinates for compounds 2, 3, 4 and 7 have been deposited at the Cambridge Crystallographic Database under accession numbers 1412068, 1412062, 1412063 and 1412064 respectively.\n\nSupplemental Material - nature16154-s1.pdf
Supplemental Material - nature16154-s2.zip
Supplemental Material - nature16154-s3.xlsx
Supplemental Material - nature16154-s4.xlsx
", "abstract": "Carbon dioxide is the ultimate source of the fossil fuels that are both central to modern life and problematic: their use increases atmospheric levels of greenhouse gases, and their availability is geopolitically constrained. Using carbon dioxide as a feedstock to produce synthetic fuels might, in principle, alleviate these concerns. Although many homogeneous and heterogeneous catalysts convert carbon dioxide to carbon monoxide, further deoxygenative coupling of carbon monoxide to generate useful multicarbon products is challenging. Molybdenum and vanadium nitrogenases are capable of converting carbon monoxide into hydrocarbons under mild conditions, using discrete electron and proton sources. Electrocatalytic reduction of carbon monoxide on copper catalysts also uses a combination of electrons and protons, while the industrial Fischer\u2013Tropsch process uses dihydrogen as a combined source of electrons and electrophiles for carbon monoxide coupling at high temperatures and pressures6. However, these enzymatic and heterogeneous systems are difficult to probe mechanistically. Molecular catalysts have been studied extensively to investigate the elementary steps by which carbon monoxide is deoxygenated and coupled, but a single metal site that can efficiently induce the required scission of carbon\u2013oxygen bonds and generate carbon\u2013carbon bonds has not yet been documented. Here we describe a molybdenum compound, supported by a terphenyl\u2013diphosphine ligand, that activates and cleaves the strong carbon\u2013oxygen bond of carbon monoxide, enacts carbon\u2013carbon coupling, and spontaneously dissociates the resulting fragment. This complex four-electron transformation is enabled by the terphenyl\u2013diphosphine ligand, which acts as an electron reservoir and exhibits the coordinative flexibility needed to stabilize the different intermediates involved in the overall reaction sequence. We anticipate that these design elements might help in the development of efficient catalysts for converting carbon monoxide to chemical fuels, and should prove useful in the broader context of performing complex multi-electron transformations at a single metal site.", "date": "2016-01-07", "date_type": "published", "publication": "Nature", "volume": "592", "number": "7584", "publisher": "Nature Publishing Group", "pagerange": "72-75", "id_number": "CaltechAUTHORS:20151222-154856232", "issn": "0028-0836", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151222-154856232", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "NSF Graduate Research Fellowship" } ] }, "doi": "10.1038/nature16154", "primary_object": { "basename": "nature16154-s1.pdf", "url": "https://authors.library.caltech.edu/records/yfzjz-5a630/files/nature16154-s1.pdf" }, "related_objects": [ { "basename": "nature16154-s2.zip", "url": "https://authors.library.caltech.edu/records/yfzjz-5a630/files/nature16154-s2.zip" }, { "basename": "nature16154-s3.xlsx", "url": "https://authors.library.caltech.edu/records/yfzjz-5a630/files/nature16154-s3.xlsx" }, { "basename": "nature16154-s4.xlsx", "url": "https://authors.library.caltech.edu/records/yfzjz-5a630/files/nature16154-s4.xlsx" } ], "resource_type": "article", "pub_year": "2016", "author_list": "Buss, Joshua A. and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/tmmea-ka390", "eprint_id": 61989, "eprint_status": "archive", "datestamp": "2023-08-20 09:04:43", "lastmod": "2023-10-25 16:07:36", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "De-Ruiter-Graham", "name": { "family": "De Ruiter", "given": "Graham" }, "orcid": "0000-0001-6008-286X" }, { "id": "Thompson-Niklas-B", "name": { "family": "Thompson", "given": "Niklas B." }, "orcid": "0000-0003-2745-4945" }, { "id": "Lionetti-Davide", "name": { "family": "Lionetti", "given": "Davide" }, "orcid": "0000-0002-4937-886X" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Nitric Oxide Activation by Distal Redox Modulation in Tetranuclear Iron Nitrosyl Complexes", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2015 American Chemical Society. \n\nReceived: July 15, 2015. Publication Date (Web): September 21, 2015. \n\nThis research was supported by the California Institute of Technology and the NIH (R01-GM102687A). T.A. is a Sloan, Dreyfus, and Cottrell fellow. T.A. and G.de.R. are grateful for a Camille & Henry Dreyfus Environmental Chemistry Fellowship. We thank Michael K. Takase and Lawrence M. Henling for assistance with crystallography. In addition, we would like to thank the anonymous referees for providing useful comments and suggestions. \n\nThe authors declare no competing financial interest.\n\nAccepted Version - nihms-785199.pdf
Supplemental Material - ja5b07397_si_001.cif
Supplemental Material - ja5b07397_si_002.cif
Supplemental Material - ja5b07397_si_003.cif
Supplemental Material - ja5b07397_si_004.cif
Supplemental Material - ja5b07397_si_005.cif
Supplemental Material - ja5b07397_si_006.cif
Supplemental Material - ja5b07397_si_007.pdf
", "abstract": "A series of tetranuclear iron complexes displaying a site-differentiated metal center was synthesized. Three of the metal centers are coordinated to our previously reported ligand, based on a 1,3,5-triarylbenzene motif with nitrogen and oxygen donors. The fourth (apical) iron center is coordinatively unsaturated and appended to the trinuclear core through three bridging pyrazolates and an interstitial \u03bc_4-oxide moiety. Electrochemical studies of complex [LFe_3(PhPz)3OFe][OTf]_2 revealed three reversible redox events assigned to the Fe^(II)_4/Fe^(II)_3Fe^(III) (\u22121.733 V), Fe^(II)_3Fe^(III)/Fe^(II)_2Fe^(III)_2 (\u22120.727 V), and Fe^(II)_2Fe^(III)_2/Fe^(II)Fe^(III)_3 (0.018 V) redox couples. Combined M\u00f6ssbauer and crystallographic studies indicate that the change in oxidation state is exclusively localized at the triiron core, without changing the oxidation state of the apical metal center. This phenomenon is assigned to differences in the coordination environment of the two metal sites and provides a strategy for storing electron and hole equivalents without affecting the oxidation state of the coordinatively unsaturated metal. The presence of a ligand-binding site allowed the effect of redox modulation on nitric oxide activation by an Fe^(II) metal center to be studied. Treatment of the clusters with nitric oxide resulted in binding of NO to the apical iron center, generating a {FeNO}^7 moiety. As with the NO-free precursors, the three reversible redox events are localized at the iron centers distal from the NO ligand. Altering the redox state of the triiron core resulted in significant change in the NO stretching frequency, by as much as 100 cm^(\u20131). The increased activation of NO is attributed to structural changes within the clusters, in particular, those related to the interaction of the metal centers with the interstitial atom. The differences in NO activation were further shown to lead to differential reactivity, with NO disproportionation and N_2O formation performed by the more electron-rich cluster.", "date": "2015-11-11", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "137", "number": "44", "publisher": "American Chemical Society", "pagerange": "14094-14106", "id_number": "CaltechAUTHORS:20151109-102021262", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151109-102021262", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01-GM102687A" }, { "agency": "Camille and Henry Dreyfus Foundation" } ] }, "doi": "10.1021/jacs.5b07397", "pmcid": "PMC4871614", "primary_object": { "basename": "ja5b07397_si_003.cif", "url": "https://authors.library.caltech.edu/records/tmmea-ka390/files/ja5b07397_si_003.cif" }, "related_objects": [ { "basename": "ja5b07397_si_004.cif", "url": "https://authors.library.caltech.edu/records/tmmea-ka390/files/ja5b07397_si_004.cif" }, { "basename": "ja5b07397_si_005.cif", "url": "https://authors.library.caltech.edu/records/tmmea-ka390/files/ja5b07397_si_005.cif" }, { "basename": "ja5b07397_si_006.cif", "url": "https://authors.library.caltech.edu/records/tmmea-ka390/files/ja5b07397_si_006.cif" }, { "basename": "ja5b07397_si_007.pdf", "url": "https://authors.library.caltech.edu/records/tmmea-ka390/files/ja5b07397_si_007.pdf" }, { "basename": "nihms-785199.pdf", "url": "https://authors.library.caltech.edu/records/tmmea-ka390/files/nihms-785199.pdf" }, { "basename": "ja5b07397_si_001.cif", "url": "https://authors.library.caltech.edu/records/tmmea-ka390/files/ja5b07397_si_001.cif" }, { "basename": "ja5b07397_si_002.cif", "url": "https://authors.library.caltech.edu/records/tmmea-ka390/files/ja5b07397_si_002.cif" } ], "resource_type": "article", "pub_year": "2015", "author_list": "De Ruiter, Graham; Thompson, Niklas B.; et el." }, { "id": "https://authors.library.caltech.edu/records/ec8m2-n2p67", "eprint_id": 61983, "eprint_status": "archive", "datestamp": "2023-08-20 08:47:20", "lastmod": "2023-10-25 16:07:19", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Edouard-G-A", "name": { "family": "Edouard", "given": "Guy A." } }, { "id": "Kelley-P", "name": { "family": "Kelley", "given": "Paul" } }, { "id": "Herbert-D-E", "name": { "family": "Herbert", "given": "David E." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Aryl Ether Cleavage by Group 9 and 10 Transition Metals: Stoichiometric Studies of Selectivity and Mechanism", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2015 American Chemical Society. \n\nReceived: August 17, 2015. Published: October 28, 2015. \n\nWe thank Lawerence M. Henling, Michael K. Takase, and Michael W. Day for crystallographic assistance and David VanderVelde for NMR assistance. We are grateful to Caltech and BP for funding. T.A. is grateful for Sloan, Cottrell, and Dreyfus fellowships. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - om5b00710_si_001.cif
Supplemental Material - om5b00710_si_002.pdf
", "abstract": "The reactivity of terphenyl diphosphines bearing aryl\u2013methyl ether or aryl\u2013aryl ether moieties with M^0 (M = Ni, Pd, Pt), M\u2032^I (M\u2032 = Co, Rh, Ir), or M^(II) centers was investigated to gain mechanistic insight into intramolecular aryl\u2013ether bond cleavage in structurally related metal complexes. Rh^I converts the aryl\u2013methyl ether moiety to an aryl C\u2013H bond. This is similar to reactivity previously observed at Ni^0 that involves C\u2013O oxidative addition, \u03b2-H elimination liberating CH_2O, reductive elimination of an aryl C\u2013H bond, and decarbonylation of CH_2O. Ir^I leads to unselective aryl and alkyl C\u2013O bond activation. In the presence of excess CO, Rh^I and Ir^I display a shift in selectivity and reactivity and cleave the alkyl C\u2013O bond. Co^I does not perform C\u2013O cleavage. Alkyl C\u2013O bond activation was observed with MII\u2013halide complexes with loss of MeCl via a Lewis acid\u2013base mechanism. Pd^0 and Pt^0 cleave selectively the O\u2013Me bond via oxidative addition. With a diaryl ether moiety, Pd^0 and Pt^0 are found to be capable of performing aryl C\u2013O bond activation. Various levels of interactions between the central arene and the metal center were observed, and these were correlated with trends in bond activation. Overall, selective cleavage of the stronger aryl ether C\u2013O bond was observed only with Ni^0 and Rh^I. Pd^0 and Pt^0 can perform aryl ether C\u2013O cleavage, but if available, they will cleave the weaker O\u2013Me bond. This study provides insight into the relative reactivity of group 9 and 10 metal centers with aryl ether bonds and suggests future directions for designing systems for metal-catalyzed cleavage of ether C\u2013O bonds in synthetic methodology as well as lignin deoxygenation.", "date": "2015-10-28", "date_type": "published", "publication": "Organometallics", "volume": "34", "number": "21", "publisher": "American Chemical Society", "pagerange": "5254-5277", "id_number": "CaltechAUTHORS:20151109-100104895", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151109-100104895", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "BP" }, { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Cottrell Scholar of Research Corporation" }, { "agency": "Camille and Henry Dreyfus Foundation" } ] }, "doi": "10.1021/acs.organomet.5b00710", "primary_object": { "basename": "om5b00710_si_001.cif", "url": "https://authors.library.caltech.edu/records/ec8m2-n2p67/files/om5b00710_si_001.cif" }, "related_objects": [ { "basename": "om5b00710_si_002.pdf", "url": "https://authors.library.caltech.edu/records/ec8m2-n2p67/files/om5b00710_si_002.pdf" } ], "resource_type": "article", "pub_year": "2015", "author_list": "Edouard, Guy A.; Kelley, Paul; et el." }, { "id": "https://authors.library.caltech.edu/records/mp2d1-6eb40", "eprint_id": 59876, "eprint_status": "archive", "datestamp": "2023-08-20 08:38:11", "lastmod": "2023-10-23 22:47:52", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Horak-K-T", "name": { "family": "Horak", "given": "Kyle T." } }, { "id": "VanderVelde-D-G", "name": { "family": "VanderVelde", "given": "David G." }, "orcid": "0000-0002-2907-0366" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Tuning of Metal Complex Electronics and Reactivity by Remote Lewis Acid Binding to \u03c0-Coordinated Pyridine Diphosphine Ligands", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2015 American Chemical Society. \n\nReceived: June 29, 2015; Publication Date (Web): August 20, 2015. \n\nSpecial Issue: Gregory Hillhouse Issue. \n\nWe thank Lawrence M. Henling and Mike Takase for crystallographic assistance. We are grateful to Caltech and the NSF (CHE-1151918) for funding. T.A. is grateful for Sloan, Cottrell, and Dreyfus fellowships. The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF CRIF:MU award to Caltech (CHE0639094). \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - om5b00562_si_001.pdf
Supplemental Material - om5b00562_si_002.cif
Supplemental Material - om5b00562_si_003.cif
Supplemental Material - om5b00562_si_004.cif
Supplemental Material - om5b00562_si_005.cif
Supplemental Material - om5b00562_si_006.cif
Supplemental Material - om5b00562_si_007.cif
Supplemental Material - om5b00562_si_008.cif
Supplemental Material - om5b00562_si_009.cif
Supplemental Material - om5b00562_si_010.cif
Supplemental Material - om5b00562_si_011.cif
", "abstract": "Metal complexes supported by ligands with chemically modifiable pendant groups are of interest for controlling reactivity. We report on the coordination chemistry and reactivity of a multidentate phosphine ligand framework that contains a Lewis acid binding site. 3,5-Bis(2-phosphinophenyl)pyridine coordinates low-oxidation-state metal centers such as Ni^0 and Pd^0 via the phosphine donors and the \u03c0 system of the heterocycle. Electrophilic reagents such as B(C_6F_5)_3, Me+, and BCy_2OTf bind the available pyridine nitrogen, generating the Ni complexes 2Ni-B(C_6F_5)_3, 2Ni-Me, and 2Ni-BCy_2OTf, respectively. Analogous compounds were prepared for Pd (2Pd, 2Pd-B(C_6F_5)_3, and 2Pd-H). The effect of Lewis acid binding was evaluated by single-crystal X-ray diffraction studies and spectroscopy. Lewis acid binding to 2Pd leads to a stronger \u03b71 interaction between the metal and the heterocycle \u03c0 system. Ni binds in an \u03b7^2 fashion, but the Lewis acid free species is not monomeric. Ni coordination results in disruption of pyridine aromaticity, as indicated by localization of double- and single-bond character in the solid state. CO adducts were prepared for Lewis acid free (4Ni) and Lewis acid bound species (H+-, Me+-, and B(C_6F_5)_3-bound; 4Ni-H, 4Ni-Me, and 4Ni-B(C_6F_5)_3) that show a significant shift of the CO stretching frequency from 1930 to 1966\u20131976 cm^(\u20131), respectively, indicating communication of ligand electronics to the metal center. An NO adduct (5Ni) with negligible metal\u2013pyridine interactions was obtained upon sequential reaction of 2Ni with [OMe_3][BF_4] and then [NO][BF_4]. Treatment of 2Ni with silanes and boranes results in pyridine dearomatization involving heteroatom\u2013H bond activation, with the heteroatom binding to the pyridine nitrogen and the hydrides delivered to the ortho position of pyridine. This reactivity demonstrates that the pendant pyridine is drastically affected by metal binding, enabling unusual ligand-based substrate activation. The described chemistry highlights a strategy for tuning the properties of metal centers by ligand postsynthetic modifications.", "date": "2015-10-12", "date_type": "published", "publication": "Organometallics", "volume": "34", "number": "19", "publisher": "American Chemical Society", "pagerange": "4753-4765", "id_number": "CaltechAUTHORS:20150825-101106456", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150825-101106456", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Cottrell Scholar of Research Corporation" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "NSF", "grant_number": "CHE-0639094" } ] }, "doi": "10.1021/acs.organomet.5b00562", "primary_object": { "basename": "om5b00562_si_003.cif", "url": "https://authors.library.caltech.edu/records/mp2d1-6eb40/files/om5b00562_si_003.cif" }, "related_objects": [ { "basename": "om5b00562_si_010.cif", "url": "https://authors.library.caltech.edu/records/mp2d1-6eb40/files/om5b00562_si_010.cif" }, { "basename": "om5b00562_si_011.cif", "url": "https://authors.library.caltech.edu/records/mp2d1-6eb40/files/om5b00562_si_011.cif" }, { "basename": "om5b00562_si_001.pdf", "url": "https://authors.library.caltech.edu/records/mp2d1-6eb40/files/om5b00562_si_001.pdf" }, { "basename": "om5b00562_si_004.cif", "url": "https://authors.library.caltech.edu/records/mp2d1-6eb40/files/om5b00562_si_004.cif" }, { "basename": "om5b00562_si_005.cif", "url": "https://authors.library.caltech.edu/records/mp2d1-6eb40/files/om5b00562_si_005.cif" }, { "basename": "om5b00562_si_006.cif", "url": "https://authors.library.caltech.edu/records/mp2d1-6eb40/files/om5b00562_si_006.cif" }, { "basename": "om5b00562_si_007.cif", "url": "https://authors.library.caltech.edu/records/mp2d1-6eb40/files/om5b00562_si_007.cif" }, { "basename": "om5b00562_si_008.cif", "url": "https://authors.library.caltech.edu/records/mp2d1-6eb40/files/om5b00562_si_008.cif" }, { "basename": "om5b00562_si_009.cif", "url": "https://authors.library.caltech.edu/records/mp2d1-6eb40/files/om5b00562_si_009.cif" }, { "basename": "om5b00562_si_002.cif", "url": "https://authors.library.caltech.edu/records/mp2d1-6eb40/files/om5b00562_si_002.cif" } ], "resource_type": "article", "pub_year": "2015", "author_list": "Horak, Kyle T.; VanderVelde, David G.; et el." }, { "id": "https://authors.library.caltech.edu/records/54grm-4e947", "eprint_id": 60228, "eprint_status": "archive", "datestamp": "2023-08-20 08:19:00", "lastmod": "2023-10-24 15:27:42", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Horak-K-T", "name": { "family": "Horak", "given": "Kyle T." } }, { "id": "Lin-Sibo", "name": { "family": "Lin", "given": "Sibo" }, "orcid": "0000-0001-5922-6694" }, { "id": "Rittle-J", "name": { "family": "Rittle", "given": "Jonathan" } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Heterometallic Effects in Trinuclear Complexes Supported by p-Terphenyl Diphosphine Ligands", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2015 American Chemical Society. \n\nReceived: July 6, 2015. Publication Date (Web): September 8, 2015. \n\nWe thank Lawrence M. Henling, Mike Takase, and Michael W. Day for crystallographic assistance. We are grateful to Caltech and NSF (CHE-1151918) for funding. T.A. is grateful for Sloan, Cottrell, and Dreyfus fellowships. The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF CRIF:MU award to Caltech, CHE0639094. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - om5b00579_si_001.pdf
Supplemental Material - om5b00579_si_002.cif
", "abstract": "A series of isostructural trinuclear complexes of metal composition Pd_2Fe, Pd_2Co, and Ni_2Fe was synthesized in a stepwise fashion. Using dinuclear precursors (Pd^I_2 and Ni_^I_2) supported by p-terphenyl diphosphine ligands allowed for the selective incorporation of a single additional metal center. The effects of both metal composition and ligand electronics on cluster properties were studied. These results highlight the importance of metal\u2013metal interactions in mixed-metal sites of structurally analogous clusters.", "date": "2015-09-28", "date_type": "published", "publication": "Organometallics", "volume": "34", "number": "18", "publisher": "American Chemical Society", "pagerange": "4429-4432", "id_number": "CaltechAUTHORS:20150914-124302805", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150914-124302805", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Cottrell Scholar of Research Corporation" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "NSF", "grant_number": "CHE-0639094" } ] }, "doi": "10.1021/acs.organomet.5b00579", "primary_object": { "basename": "om5b00579_si_001.pdf", "url": "https://authors.library.caltech.edu/records/54grm-4e947/files/om5b00579_si_001.pdf" }, "related_objects": [ { "basename": "om5b00579_si_002.cif", "url": "https://authors.library.caltech.edu/records/54grm-4e947/files/om5b00579_si_002.cif" } ], "resource_type": "article", "pub_year": "2015", "author_list": "Horak, Kyle T.; Lin, Sibo; et el." }, { "id": "https://authors.library.caltech.edu/records/s4vym-kha78", "eprint_id": 59341, "eprint_status": "archive", "datestamp": "2023-08-22 16:20:57", "lastmod": "2023-10-23 20:28:11", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Suseno-Sandy", "name": { "family": "Suseno", "given": "Sandy" } }, { "id": "McCrory-Charles-C-L", "name": { "family": "McCrory", "given": "Charles C. L." }, "orcid": "0000-0001-9039-7192" }, { "id": "Tran-Rosalie", "name": { "family": "Tran", "given": "Rosalie" } }, { "id": "Gul-Sheraz", "name": { "family": "Gul", "given": "Sheraz" }, "orcid": "0000-0001-8920-8737" }, { "id": "Yano-Junko", "name": { "family": "Yano", "given": "Junko" }, "orcid": "0000-0001-6308-9071" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Molecular Mixed-Metal Manganese Oxido Cubanes as Precursors to Heterogeneous Oxygen Evolution Catalysts", "ispublished": "pub", "full_text_status": "public", "keywords": "cubanes; electrocatalysis; manganese; metal oxides; oxygen evolution reaction", "note": "\u00a9 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.\n\nReceived: March 20, 2015. Article first published online: 4 Aug. 2015.\n\nThis work was supported by Caltech, the NSF CAREER grant CHE-1151918 and the NIH grant R01 GM102687A (T.A.). T.A. is a Sloan, Cottrell, and Dreyfus fellow. Rotating-disk voltammetry and 2 h stability measurements are based on work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under award no. DESC0004993. Portions of this research were carried out at the SSRL, operated by Stanford University for the U.S. DOE Office of Science, and supported by the DOE and NIH. X-ray spectroscopy studies were supported by the NIH (R.T.) and by the Director of the OBES, Division of Chemical Sciences, Geosciences, and Biosciences, DOE (J.Y.). We thank James D. Blakemore for helpful discussions, Nathan Dalleska for assistance in ICP-MS data acquisition, and Tim Davenport for assistance in TGA studies. We thank Dr. Jordi Cabana and Dr. Ulrike Boesenberg for providing the NiO reference spectrum. Research was in part carried out at the Molecular Materials Research Center of the Beckman Institute of the California Institute of Technology. This project benefited from the use of instrumentation made available by the Caltech Environmental Analysis Center.\n\nAccepted Version - nihms785201.pdf
Supplemental Material - chem_201501104_sm_miscellaneous_information.pdf
", "abstract": "Well-defined mixed-metal [CoMn\u2083O\u2084] and [NiMn\u2083O\u2084] cubane complexes were synthesized and used as precursors for heterogeneous oxygen evolution reaction (OER) electrocatalysts. The discrete clusters were dropcasted onto glassy carbon (GC) and indium tin oxide (ITO) electrodes, and the OER activities of the resulting films were evaluated. The catalytic surfaces were analyzed by various techniques to gain insight into the structure-function relationships of the electrocatalysts' heterometallic composition. Depending on preparation conditions, the Co-Mn oxide was found to change metal composition during catalysis, while the Ni\u2013Mn oxides maintained the NiMn\u2083 ratio. XAS studies provided structural insights indicating that the electrocatalysts are different from the molecular precursors, but that the original NiMn\u2083O\u2084 cubane-like geometry was maintained in the absence of thermal treatment (2-Ni). In contrast, the thermally generated 3-Ni develops an oxide-like extended structure. Both 2-Ni and 3-Ni undergo structural changes upon electrolysis, but they do not convert into the same material. The observed structural motifs in these heterogeneous electrocatalysts are reminiscent of the biological oxygen-evolving complex in Photosystem II, including the MMn\u2083O\u2084 cubane moiety. The reported studies demonstrate the use of discrete heterometallic oxide clusters as precursors for heterogeneous water oxidation catalysts of novel composition and the distinct behavior of two sets of mixed metal oxides.", "date": "2015-09-14", "date_type": "published", "publication": "Chemistry: a European Journal", "volume": "21", "number": "38", "publisher": "John Wiley & Sons", "pagerange": "13420-13430", "id_number": "CaltechAUTHORS:20150810-085304566", "issn": "0947-6539", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150810-085304566", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "NIH", "grant_number": "R01 GM102687A" }, { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Cottrell Scholar of Research Corporation" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Department of Energy (DOE)", "grant_number": "SC0004993" } ] }, "local_group": { "items": [ { "id": "JCAP" } ] }, "doi": "10.1002/chem.201501104", "pmcid": "PMC4868073", "primary_object": { "basename": "chem_201501104_sm_miscellaneous_information.pdf", "url": "https://authors.library.caltech.edu/records/s4vym-kha78/files/chem_201501104_sm_miscellaneous_information.pdf" }, "related_objects": [ { "basename": "nihms785201.pdf", "url": "https://authors.library.caltech.edu/records/s4vym-kha78/files/nihms785201.pdf" } ], "resource_type": "article", "pub_year": "2015", "author_list": "Suseno, Sandy; McCrory, Charles C. L.; et el." }, { "id": "https://authors.library.caltech.edu/records/kpc9z-26d65", "eprint_id": 56643, "eprint_status": "archive", "datestamp": "2023-08-20 05:09:10", "lastmod": "2023-10-23 15:39:42", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Synthetic cluster models of the biological oxygen evolving catalyst from photosystem II", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2015 American Chemical Society.", "abstract": "Redox- inactive metals are found in biol. and heterogeneous water oxidn. catalysts, but their roles are currently not well\nunderstood. With current schemes of energy conversion involving water oxidn. and dioxygen redn., a detailed understanding of\nthese systems is imperative for the rational development of practical catalysts. Targeting synthetic model clusters of these\ncatalysts, multinucleating ligands were developed for Earth abundant first- row transition metals (Mn^(2+), Fe^(2+), Co^(2+), Ni^(2+), Cu^(2+),\nZn)^(2+). Trimetallic complexes were utilized as precursors to more elaborate metal oxide clusters. Tetranuclear complexes\ndisplaying Mn_4, Mn_3Ca and other Mn_3M motifs with varied no. of bridging oxo ligands were synthesized. The redn. potentials of\nthese clusters span a window of over 1 V. With the pK_a of the redox- inactive metal- aqua complex as a measure of Lewis\nacidity, structurally analogous series of clusters display linear dependence between redn. potential and acidity. These findings\nprovide a general strategy for tuning the clusters over a wide range of potentials and reactivity modes. Implications for the\nfunction of biol. and artificial oxygen evolving catalysts will be discussed.", "date": "2015-03", "date_type": "published", "publication": "Abstracts of Papers of the American Chemical Society", "volume": "249", "publisher": "American Chemical Society", "pagerange": "INOR-423", "id_number": "CaltechAUTHORS:20150414-135354477", "issn": "0065-7727", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150414-135354477", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "article", "pub_year": "2015", "author_list": "Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/cq9ry-js448", "eprint_id": 55785, "eprint_status": "archive", "datestamp": "2023-08-20 04:52:35", "lastmod": "2023-10-20 23:10:50", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Henthorn-J-T", "name": { "family": "Henthorn", "given": "Justin T." }, "orcid": "0000-0003-4876-2680" }, { "id": "Lin-Sibo", "name": { "family": "Lin", "given": "Sibo" }, "orcid": "0000-0001-5922-6694" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Combination of Redox-Active Ligand and Lewis Acid for Dioxygen Reduction with \u03c0-Bound Molybdenum\u2212Quinonoid Complexes", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2015 American Chemical Society.\n\nReceived: September 29, 2014; Revised: December 4, 2014; Published: January 10, 2015.\n\nWe thank Lawrence M. Henling and Dr. Michael Takase for crystallographic assistance, Prof. John E. Bercaw for providing access to a Toepler pump in his laboratory, and Christine Cheng for assistance in organic synthesis. We are grateful to Caltech and the NSF (CHE-1151918 to T.A.; GRFP to J.T.H.) for funding. T.A. is a Sloan, Cottrell, and Dreyfus Fellow. The APEX II X-ray diffractometer was purchased via an NSF CRIF:MU Award to Caltech (CHE-0639094).\n\nSupplemental Material - ja5100405_si_001.cif
Supplemental Material - ja5100405_si_002.pdf
", "abstract": "A series of \u03c0-bound Mo\u2212quinonoid complexes supported by pendant phosphines have been synthesized. Structural characterization revealed strong metal\u2013arene interactions between Mo and the \u03c0 system of the quinonoid fragment. The Mo\u2013catechol complex (2a) was found to react within minutes with 0.5 equiv of O_2 to yield a Mo\u2013quinone complex (3), H_2O, and CO. Si- and B-protected Mo\u2013catecholate complexes also react with O_2 to yield 3 along with (R_2SiO)_n and (ArBO)_3 byproducts, respectively. Formally, the Mo\u2013catecholate fragment provides two electrons, while the elements bound to the catecholate moiety act as acceptors for the O_2 oxygens. Unreactive by itself, the Mo\u2013dimethyl catecholate analogue reduces O_2 in the presence of added Lewis acid, B(C_6F_5)_3, to generate a MoI species and a bis(borane)-supported peroxide dianion, [[(F_5C_6)_3B]_2O_2^(2\u2013)], demonstrating single-electron-transfer chemistry from Mo to the O_2 moiety. The intramolecular combination of a molybdenum center, redox-active ligand, and Lewis acid reduces O_2 with pendant acids weaker than B(C_6F_5)_3. Overall, the \u03c0-bound catecholate moiety acts as a two-electron donor. A mechanism is proposed in which O_2 is reduced through an initial one-electron transfer, coupled with transfer of the Lewis acidic moiety bound to the quinonoid oxygen atoms to the reduced O_2 species.", "date": "2015-02-04", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "137", "number": "4", "publisher": "American Chemical Society", "pagerange": "1458-1464", "id_number": "CaltechAUTHORS:20150316-110108648", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150316-110108648", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "NSF Graduate Research Fellowship Program" }, { "agency": "NSF", "grant_number": "CHE-0639094" }, { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Cottrell Scholar of Research Corporation" }, { "agency": "Camille and Henry Dreyfus Foundation" } ] }, "doi": "10.1021/ja5100405", "primary_object": { "basename": "ja5100405_si_001.cif", "url": "https://authors.library.caltech.edu/records/cq9ry-js448/files/ja5100405_si_001.cif" }, "related_objects": [ { "basename": "ja5100405_si_002.pdf", "url": "https://authors.library.caltech.edu/records/cq9ry-js448/files/ja5100405_si_002.pdf" } ], "resource_type": "article", "pub_year": "2015", "author_list": "Henthorn, Justin T.; Lin, Sibo; et el." }, { "id": "https://authors.library.caltech.edu/records/sf1tc-70y49", "eprint_id": 53099, "eprint_status": "archive", "datestamp": "2023-08-20 04:31:44", "lastmod": "2023-10-19 14:32:14", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lin-Po-Heng", "name": { "family": "Lin", "given": "Po-Heng" } }, { "id": "Takase-M-K", "name": { "family": "Takase", "given": "Michael K." }, "orcid": "0000-0001-8365-3645" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Investigations of the Effect of the Non-Manganese Metal in Heterometallic-Oxido Cluster Models of the Oxygen Evolving Complex of Photosystem II: Lanthanides as Substitutes for Calcium", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2014 American Chemical Society. ACS AuthorChoice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. \n\nReceived: June 28, 2014; Published: December 18, 2014. \n\nThis work was supported by the California Institute of\nTechnology and the NIH R01 GM102687A (T.A.). T.A. is a\nSloan, Dreyfus, and Cottrell fellow. We thank Lawrence M.\nHenling for assistance with crystallography and Zhiji Han for\nassistance with the characterization of the Ce complexes. The\nBruker KAPPA APEXII X-ray diffractometer was purchased via\nan NSF Chemistry Research Instrumentation award to Caltech\n(CHE-0639094).\n\nPublished - ic5015219.pdf
Supplemental Material - ic5015219_si_001.cif
Supplemental Material - ic5015219_si_002.pdf
", "abstract": "We report the syntheses and electrochemical properties of nine new clusters ([LLnMn^(IV)_(3)O_4(OAc)_3(DMF)_n]^+ (Ln = La^3+, Ce^3+, Nd^3+, Eu^3+, Gd^3+, Tb^3+, Dy^3+, Yb^3+, and Lu^3+, n = 2 or 3)) supported by a ligand (L^3\u2013) based on a 1,3,5-triarylbenzene motif appended with alkoxide and pyridine donors. All complexes were obtained by metal substitution of Ca2+ with lanthanides upon treatment of previously reported LMn_3CaO_4(OAc)_3(THF) with Ln(OTf)_3. Structural characterization confirmed that the clusters contain the [LnMn_3O_4] cubane motif. The effect of the redox-inactive centers on the electronic properties of the Mn_3O_4 cores was investigated by cyclic voltammetry. A linear correlation between the redox potential of the cluster and the ionic radii or pKa of the lanthanide metal ion was observed. Chemical reduction of the LMn^(IV)_3GdO_4(OAc)_3(DMF)2 cluster with decamethylferrocene, resulted in the formation of LGdMn^(IV)_2Mn^(III)O_4(OAc)_3(DMF)_2, a rare example of mixed-valence [MMn_3O_4] cubane. The lanthanide-coordinated ligands can be substituted with other donors, including water, the biological substrate.", "date": "2015-01-05", "date_type": "published", "publication": "Inorganic Chemistry", "volume": "54", "number": "1", "publisher": "American Chemical Society", "pagerange": "59-64", "id_number": "CaltechAUTHORS:20141222-131120714", "issn": "0020-1669", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141222-131120714", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "NIH", "grant_number": "R01 GM102687A" }, { "agency": "NSF", "grant_number": "CHE-0639094" } ] }, "doi": "10.1021/ic5015219", "pmcid": "PMC4286168", "primary_object": { "basename": "ic5015219.pdf", "url": "https://authors.library.caltech.edu/records/sf1tc-70y49/files/ic5015219.pdf" }, "related_objects": [ { "basename": "ic5015219_si_001.cif", "url": "https://authors.library.caltech.edu/records/sf1tc-70y49/files/ic5015219_si_001.cif" }, { "basename": "ic5015219_si_002.pdf", "url": "https://authors.library.caltech.edu/records/sf1tc-70y49/files/ic5015219_si_002.pdf" } ], "resource_type": "article", "pub_year": "2015", "author_list": "Lin, Po-Heng; Takase, Michael K.; et el." }, { "id": "https://authors.library.caltech.edu/records/gr919-gk273", "eprint_id": 48278, "eprint_status": "archive", "datestamp": "2023-08-22 14:28:45", "lastmod": "2023-10-17 18:39:58", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Tsui-Emily-Y", "name": { "family": "Tsui", "given": "Emily Y." }, "orcid": "0000-0001-6419-3954" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Carbon dioxide cleavage by a Ni_2 complex supported by a binucleating bis(N-heterocyclic carbene) framework", "ispublished": "pub", "full_text_status": "public", "keywords": "Bimetallic complexes; NHC; Carbon dioxide activation; Nickel; Metal-arene interactions", "note": "\u00a9 2014 Elsevier Ltd. \n\nReceived 6 May 2014; Accepted 18 June 2014; Available online 2 July 2014. \n\nThis work was supported by the California Institute of Technology, NSF CAREER Grant CHE-1151918 (to T.A.), and a Sandia Campus Executive Fellowship (to E.Y.T.). TA is a Sloan, Cottrell, and Dreyfus fellow. We thank L. M. Henling for assistance with crystallography. The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF Chemistry Research Instrumentation award to Caltech (CHE-0639094). The 400 MHz NMR spectrometer was purchased via NIH Award RR027690.\n\nAccepted Version - nihms918005.pdf
", "abstract": "A binucleating bis(N-heterocyclic carbene) ligand was designed as a means to coordinate and proximally constrain two transition metal centers. Using an imidazopyridine-based NHC afforded a framework structurally related to previously reported para-terphenyl diphosphines. Bimetallic copper, cobalt, and nickel complexes supported by this framework were synthesized and structurally characterized. Strong interactions between the metal centers and the central arene were observed in all nickel complexes. Dinickel(0) complexes of this ligand framework were found to react with CO_2 to form a dicarbonyl-bridged dinickel(0) product, demonstrating facile CO_2 reduction.", "date": "2014-12-14", "date_type": "published", "publication": "Polyhedron", "volume": "84", "publisher": "Elsevier", "pagerange": "103-110", "id_number": "CaltechAUTHORS:20140811-082151558", "issn": "0277-5387", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140811-082151558", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "Sandia National Laboratories" }, { "agency": "NSF", "grant_number": "CHE-0639094" }, { "agency": "NIH", "grant_number": "RR027690" }, { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Cottrell Scholar of Research Corporation" }, { "agency": "Camille and Henry Dreyfus Foundation" } ] }, "doi": "10.1016/j.poly.2014.06.041", "pmcid": "PMC6214461", "primary_object": { "basename": "nihms918005.pdf", "url": "https://authors.library.caltech.edu/records/gr919-gk273/files/nihms918005.pdf" }, "resource_type": "article", "pub_year": "2014", "author_list": "Tsui, Emily Y. and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/j8k8q-nb146", "eprint_id": 56032, "eprint_status": "archive", "datestamp": "2023-08-20 04:00:51", "lastmod": "2023-10-20 23:34:29", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Martin-Diaconescu-V", "name": { "family": "Martin-Diaconescu", "given": "Vlad" } }, { "id": "Gennari-M", "name": { "family": "Gennari", "given": "Marcello" } }, { "id": "Gerey-B", "name": { "family": "Gerey", "given": "Bertrand" } }, { "id": "Tsui-Emily-Y", "name": { "family": "Tsui", "given": "Emily" }, "orcid": "0000-0001-6419-3954" }, { "id": "Kanady-J-S", "name": { "family": "Kanady", "given": "Jacob" } }, { "id": "Tran-Rosalie", "name": { "family": "Tran", "given": "Rosalie" } }, { "id": "P\u00e9caut-J", "name": { "family": "P\u00e9caut", "given": "Jacques" } }, { "id": "Maganas-D", "name": { "family": "Maganas", "given": "Dimitrios" } }, { "id": "Krewald-V", "name": { "family": "Krewald", "given": "Vera" } }, { "id": "Gour\u00e9-E", "name": { "family": "Gour\u00e9", "given": "Eric" } }, { "id": "Duboc-C", "name": { "family": "Duboc", "given": "Carole" } }, { "id": "Yano-Junko", "name": { "family": "Yano", "given": "Junko" }, "orcid": "0000-0001-6308-9071" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Collomb-M-N", "name": { "family": "Collomb", "given": "Marie-Noelle" } }, { "id": "DeBeer-S", "name": { "family": "DeBeer", "given": "Serena" }, "orcid": "0000-0002-5196-3400" } ] }, "title": "Ca K\u2011Edge XAS as a Probe of Calcium Centers in Complex Systems", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2014 American Chemical Society. ACS Editors' Choice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. \n\nReceived: August 15, 2014. Published: December 10, 2014. \n\nV.M.-D., D.M., V.K., and S.D. acknowledge the Max Planck Society for funding. S.D. acknowledges a Sloan Fellowship. B.G. thanks the \"Universit\u00e9 Joseph Fourier of Grenoble\" for his Ph.D. grant. The Authors acknowledge support from ICMG FR 2067, COST CM1202 program (PERSPECT H2O), LABEX ARCANE (ANR-11-LABX-0003-01), the French National Research Agency (ANR-09-JCJC-0087 (MANGACOM), and ANR-13-BS07-0015-01 (MnCaOEC)) for financial support including M.G.'s and E.G.'s fellowships. We are grateful to the NIH (R01 GM102687A to T.A.); Dreyfus, Sloan, and Cottrell fellowships (T.A.); the NSF (GRFP to J.K. and E.T.); and Sandia National Laboratory (fellowship to E.T.) for funding. A portion of the XAS work was supported by NIH Grant F32GM100595 (R.T.), and by the Director of the Office of Basic Energy Science (OBES), Division of Chemical Sciences, Geosciences, and Biosciences, DOE, under contract DE-AC02-05CH11231 (J.Y). Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No.DE-AC02-76SF00515. Parts of this research were carried out at the light source DORIS at DESY, a member of the Helmholtz Association (HGF). We would like to thank Dr. Edmund Welter for assistance in using beamline A.1.\n\nPublished - ic501991e.pdf
Supplemental Material - ic501991e_si_001.pdf
Supplemental Material - ic501991e_si_002.cif
", "abstract": "Herein, Ca K-edge X-ray absorption spectroscopy (XAS) is developed as a means to characterize the local environment of calcium centers. The spectra for six, seven, and eight coordinate inorganic and molecular calcium complexes were analyzed and determined to be primarily influenced by the coordination environment and site symmetry at the calcium center. The experimental results are closely correlated to time-dependent density functional theory (TD-DFT) calculations of the XAS spectra. The applicability of this methodology to complex systems was investigated using structural mimics of the oxygen-evolving complex (OEC) of PSII. It was found that Ca K-edge XAS is a sensitive probe for structural changes occurring in the cubane heterometallic cluster due to Mn oxidation. Future applications to the OEC are discussed.", "date": "2014-12-10", "date_type": "published", "publication": "Inorganic Chemistry", "volume": "54", "number": "4", "publisher": "American Chemical Society", "pagerange": "1283-1292", "id_number": "CaltechAUTHORS:20150324-125850453", "issn": "0020-1669", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150324-125850453", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Max Planck Society" }, { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Universit\u00e9 Joseph Fourier of Grenoble" }, { "agency": "Centre National de la Recherche Scientifique (CNRS)", "grant_number": "PERSPECT H2O" }, { "agency": "Agence Nationale pour la Recherche (ANR)", "grant_number": "ANR-11-LABX-0003-01" }, { "agency": "Agence Nationale pour la Recherche (ANR)", "grant_number": "ANR-09-JCJC-0087 (MANGACOM)" }, { "agency": "Agence Nationale pour la Recherche (ANR)", "grant_number": "ANR-13-BS07-0015-01 (MnCaOEC)" }, { "agency": "NIH", "grant_number": "R01 GM102687A" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "NSF" }, { "agency": "Sandia National Laboratory" }, { "agency": "NIH Postdoctoral Fellowship", "grant_number": "F32GM100595" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-05CH11231" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-76SF00515" }, { "agency": "Cottrell Scholar of Research Corporation" } ] }, "doi": "10.1021/ic501991e", "pmcid": "PMC4331723", "primary_object": { "basename": "ic501991e.pdf", "url": "https://authors.library.caltech.edu/records/j8k8q-nb146/files/ic501991e.pdf" }, "related_objects": [ { "basename": "ic501991e_si_001.pdf", "url": "https://authors.library.caltech.edu/records/j8k8q-nb146/files/ic501991e_si_001.pdf" }, { "basename": "ic501991e_si_002.cif", "url": "https://authors.library.caltech.edu/records/j8k8q-nb146/files/ic501991e_si_002.cif" } ], "resource_type": "article", "pub_year": "2014", "author_list": "Martin-Diaconescu, Vlad; Gennari, Marcello; et el." }, { "id": "https://authors.library.caltech.edu/records/bqtj3-gzd40", "eprint_id": 50134, "eprint_status": "archive", "datestamp": "2023-08-22 14:13:18", "lastmod": "2023-10-17 22:32:25", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Henthorn-Justin-T", "name": { "family": "Henthorn", "given": "Justin T." }, "orcid": "0000-0003-4876-2680" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Dioxygen Reactivity with a Ferrocene\u2013Lewis Acid Pairing: Reduction to a Boron Peroxide in the Presence of Tris(pentafluorophenyl)borane", "ispublished": "pub", "full_text_status": "public", "keywords": "dioxygen reduction; ferrocene; peroxide; tris(pentafluorophenyl)borane", "note": "\u00a9 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.\n\nReceived: August 22, 2014.\nArticle first published online: 22 SEP 2014.\n\nWe thank Lawrence M. Henling and Dr. Michael Takase for\ncrystallographic assistance. We are grateful to Caltech and NSF GRFP (J.T.H.) for funding.\n\nSupplemental Material - ange_201408462_sm_miscellaneous_information.pdf
", "abstract": "Ferrocenes, which are typically air-stable outer-sphere single-electron transfer reagents, were found to react with dioxygen in the presence of B(C_6F_5)_3, a Lewis acid unreactive to O_2, to generate bis(borane) peroxide. Although several Group 13 peroxides have been reported, boron-supported peroxides are rare, with no structurally characterized examples of the BO_2B moiety. The synthesis of a bis(borane)-supported peroxide anion and its structural and electrochemical characterization are described.", "date": "2014-11-17", "date_type": "published", "publication": "Angewandte Chemie International Edition", "volume": "53", "number": "47", "publisher": "Wiley", "pagerange": "12893-12896", "id_number": "CaltechAUTHORS:20141001-090457258", "issn": "1433-7851", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141001-090457258", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "NSF Graduate Research Fellowship" } ] }, "doi": "10.1002/anie.201408462", "primary_object": { "basename": "ange_201408462_sm_miscellaneous_information.pdf", "url": "https://authors.library.caltech.edu/records/bqtj3-gzd40/files/ange_201408462_sm_miscellaneous_information.pdf" }, "resource_type": "article", "pub_year": "2014", "author_list": "Henthorn, Justin T. and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/dhrsg-qqd25", "eprint_id": 50258, "eprint_status": "archive", "datestamp": "2023-08-20 03:21:04", "lastmod": "2023-10-17 22:53:03", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kanady-J-S", "name": { "family": "Kanady", "given": "Jacob S." } }, { "id": "Lin-Po-Heng", "name": { "family": "Lin", "given": "Po-Heng" } }, { "id": "Carsch-K-M", "name": { "family": "Carsch", "given": "Kurtis M." }, "orcid": "0000-0003-4432-7518" }, { "id": "Nielsen-R-J", "name": { "family": "Nielsen", "given": "Robert J." }, "orcid": "0000-0002-7962-0186" }, { "id": "Takase-M-K", "name": { "family": "Takase", "given": "Michael K." }, "orcid": "0000-0001-8365-3645" }, { "id": "Goddard-W-A-III", "name": { "family": "Goddard", "given": "William A., III" }, "orcid": "0000-0003-0097-5716" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Toward Models for the Full Oxygen-Evolving Complex of Photosystem II by Ligand Coordination To Lower the Symmetry of the Mn_3CaO_4 Cubane: Demonstration That Electronic Effects Facilitate Binding of a Fifth Metal", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2014 American Chemical Society. ACS AuthorChoice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. \n\nReceived: August 8, 2014. Publication Date (Web): September 20, 2014. \n\nThis work was supported by the California Institute of\nTechnology, the NIH (R01 GM102687A, T.A.), the NSF\nGRFP (J.S.K.), and NSF (CHE-1214158, W.A.G.). T.A. is a\nSloan, Dreyfus, and Cottrell fellow. We thank Lawrence M.\nHenling for assistance with crystallography. The Bruker KAPPA\nAPEXII X-ray diffractometer was purchased via an NSF\nChemistry Research Instrumentation award to Caltech (CHE-0639094).\n\nPublished - ja508160x.pdf
Supplemental Material - ja508160x_si_001.pdf
Supplemental Material - ja508160x_si_002.cif
Supplemental Material - ja508160x_si_003.cif
Supplemental Material - ja508160x_si_004.cif
", "abstract": "Synthetic model compounds have been targeted to benchmark and better understand the electronic structure, geometry, spectroscopy, and reactivity of the oxygen-evolving complex (OEC) of photosystem II, a low-symmetry Mn_4CaO_n cluster. Herein, low-symmetry Mn^(IV)_3GdO_4 and Mn^(IV_)3CaO_4 cubanes are synthesized in a rational, stepwise fashion through desymmetrization by ligand substitution, causing significant cubane distortions. As a result of increased electron richness and desymmetrization, a specific \u03bc_3-oxo moiety of the Mn_3CaO_4 unit becomes more basic allowing for selective protonation. Coordination of a fifth metal ion, Ag+, to the same site gives a Mn_3CaAgO_4 cluster that models the topology of the OEC by displaying both a cubane motif and a \"dangler\" transition metal. The present synthetic strategy provides a rational roadmap for accessing more accurate models of the biological catalyst.", "date": "2014-10-15", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "136", "number": "41", "publisher": "American Chemical Society", "pagerange": "14373-14376", "id_number": "CaltechAUTHORS:20141008-093243995", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141008-093243995", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "NIH", "grant_number": "R01 GM102687A" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "NSF", "grant_number": "CHE-1214158" }, { "agency": "NSF", "grant_number": "CHE-0639094" } ] }, "doi": "10.1021/ja508160x", "pmcid": "PMC4210109", "primary_object": { "basename": "ja508160x.pdf", "url": "https://authors.library.caltech.edu/records/dhrsg-qqd25/files/ja508160x.pdf" }, "related_objects": [ { "basename": "ja508160x_si_001.pdf", "url": "https://authors.library.caltech.edu/records/dhrsg-qqd25/files/ja508160x_si_001.pdf" }, { "basename": "ja508160x_si_002.cif", "url": "https://authors.library.caltech.edu/records/dhrsg-qqd25/files/ja508160x_si_002.cif" }, { "basename": "ja508160x_si_003.cif", "url": "https://authors.library.caltech.edu/records/dhrsg-qqd25/files/ja508160x_si_003.cif" }, { "basename": "ja508160x_si_004.cif", "url": "https://authors.library.caltech.edu/records/dhrsg-qqd25/files/ja508160x_si_004.cif" } ], "resource_type": "article", "pub_year": "2014", "author_list": "Kanady, Jacob S.; Lin, Po-Heng; et el." }, { "id": "https://authors.library.caltech.edu/records/amqnn-g7y62", "eprint_id": 50064, "eprint_status": "archive", "datestamp": "2023-08-22 13:43:33", "lastmod": "2023-10-17 22:29:05", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lionetti-D", "name": { "family": "Lionetti", "given": "Davide" }, "orcid": "0000-0002-4937-886X" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "How calcium affects oxygen formation", "ispublished": "pub", "full_text_status": "public", "keywords": "Chemistry; Chemical biology", "note": "\u00a9 2014 Macmillan Publishers Limited.\n\nPublished online 17 September 2014.\n\nAccepted Version - nihms785221.pdf
", "abstract": "Calcium is an essential component of the catalyst that forms oxygen from water during photosynthesis. It seems that part of calcium's job is to enable the release of oxygen from this catalyst.", "date": "2014-09-25", "date_type": "published", "publication": "Nature", "volume": "513", "number": "7519", "publisher": "Nature Publishing Group", "pagerange": "495-496", "id_number": "CaltechAUTHORS:20140926-101939285", "issn": "0028-0836", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140926-101939285", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1038/nature13753", "pmcid": "PMC4879831", "primary_object": { "basename": "nihms785221.pdf", "url": "https://authors.library.caltech.edu/records/amqnn-g7y62/files/nihms785221.pdf" }, "resource_type": "article", "pub_year": "2014", "author_list": "Lionetti, Davide and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/7thfv-jd798", "eprint_id": 47888, "eprint_status": "archive", "datestamp": "2023-08-20 02:31:15", "lastmod": "2023-10-20 23:08:22", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Buss-J-A", "name": { "family": "Buss", "given": "Joshua A." }, "orcid": "0000-0002-3347-8583" }, { "id": "Edouard-G-A", "name": { "family": "Edouard", "given": "Guy A." } }, { "id": "Chen-Christine", "name": { "family": "Chen", "given": "Christine" } }, { "id": "Shi-Jade", "name": { "family": "Shi", "given": "Jade" } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Molybdenum Catalyzed Ammonia Borane Dehydrogenation: Oxidation State Specific Mechanisms", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2014 American Chemical Society. ACS AuthorChoice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. \n\nPublication Date (Web): July 17, 2014. Received: June 15, 2014. \n\nWe thank Lawrence M. Henling, Michael K. Takase, and Michael\nW. Day for crystallographic assistance, David VanderVelde for\nNMR expertise, and Aaron and Wes Sattler for helpful\ndiscussions. We are grateful to Caltech and the NSF (CHE-\n1151918) for funding. T.A. is a Sloan, Cottrell, . BILRC is acknowledged for assistance with photochemistry.\nThe NSF (CRIF:MU CHE0639094) and NIH\n(RR027690) are thanked for instrument grants to Caltech.\n\nFigures 2 and S32 incorrectly reported the units of time in\nseconds rather than minutes. These axis labels have been\nrectified in the attached versions of Figure 2 and the Supporting\nInformation to match the (correct) time scales for H2 release\nreported in the text of the manuscript.\n\nPublished - ja5059923.pdf
Supplemental Material - ja5059923_si_001.pdf
Supplemental Material - ja5059923_si_002.cif
Erratum - ja5132853.pdf
", "abstract": "Though numerous catalysts for the dehydrogenation of ammonia borane (AB) are known, those that release >2 equiv of H_2 are uncommon. Herein, we report the synthesis of Mo complexes supported by a para-terphenyl diphosphine ligand, 1, displaying metal\u2013arene interactions. Both a Mo^0 N_2 complex, 5, and a Mo^(II) bis(acetonitrile) complex, 4, exhibit high levels of AB dehydrogenation, releasing over 2.0 equiv of H_2. The reaction rate, extent of dehydrogenation, and reaction mechanism vary as a function of the precatalyst oxidation state. Several Mo hydrides (Mo^(II)(H)_2, [Mo^(II)(H)]^+, and [Mo^(IV)(H)_3]^+) relevant to AB chemistry were characterized.", "date": "2014-08-13", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "136", "number": "32", "publisher": "American Chemical Society", "pagerange": "11272-11275", "id_number": "CaltechAUTHORS:20140804-112552589", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140804-112552589", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "Cottrell Scholar of Research Corporation" }, { "agency": "NSF", "grant_number": "CHE-0639094" }, { "agency": "NIH", "grant_number": "RR027690" }, { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Camille and Henry Dreyfus Foundation" } ] }, "doi": "10.1021/ja5059923", "pmcid": "PMC4140452", "primary_object": { "basename": "ja5059923.pdf", "url": "https://authors.library.caltech.edu/records/7thfv-jd798/files/ja5059923.pdf" }, "related_objects": [ { "basename": "ja5059923_si_001.pdf", "url": "https://authors.library.caltech.edu/records/7thfv-jd798/files/ja5059923_si_001.pdf" }, { "basename": "ja5059923_si_002.cif", "url": "https://authors.library.caltech.edu/records/7thfv-jd798/files/ja5059923_si_002.cif" }, { "basename": "ja5132853.pdf", "url": "https://authors.library.caltech.edu/records/7thfv-jd798/files/ja5132853.pdf" } ], "resource_type": "article", "pub_year": "2014", "author_list": "Buss, Joshua A.; Edouard, Guy A.; et el." }, { "id": "https://authors.library.caltech.edu/records/75d61-zjk35", "eprint_id": 55958, "eprint_status": "archive", "datestamp": "2023-08-20 02:28:09", "lastmod": "2023-10-20 23:28:49", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kanady-J-S", "name": { "family": "Kanady", "given": "Jacob S." } }, { "id": "Lin-Po-Heng", "name": { "family": "Lin", "given": "Po-Heng" } }, { "id": "Tsui-Emily-Y", "name": { "family": "Tsui", "given": "Emily Y." }, "orcid": "0000-0001-6419-3954" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Synthetic strategies towards a Mn4CaOn model complex of the oxygen-evolving complex of photosystem II", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2014 American Chemical Society.", "abstract": "The oxygen-evolving complex (OEC) of photosystem II is a Mn_4CaO_5 heterometallic cluster. In the past, we\nsynthesized a structural model (1 ) of the Mn_3CaO_4 subsite of the OEC using a hexapyridyl, trialkoxide ligand.\nAddn. of the fourth, dangling manganese has been targeted to more fully mimic the structure of the OEC. The\noriginal complex 1, stabilized across three faces of the cubane by carboxylates, has been desymmetrized using\na chelating bisoximate ligand by replacing two of the \u03ba^2-carboxylates. The properties and reactivity of the\ndesymmetrized Mn_3CaO_4 complex has been compared to the original, pseudo-C_3 sym. cluster, and its redox\nand acid/base chem. has been studied, as both are pertinent to the OEC mechanism. Strategies for\nsynthesizing a Mn_4CaO-_n (n=4, 5) OEC model from the new, desymmetrized complex will be discussed.", "date": "2014-08-10", "date_type": "published", "publication": "Abstracts of Papers of the American Chemical Society", "volume": "248", "publisher": "American Chemical Society", "pagerange": "989-INOR", "id_number": "CaltechAUTHORS:20150323-084739582", "issn": "0065-7727", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150323-084739582", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "article", "pub_year": "2014", "author_list": "Kanady, Jacob S.; Lin, Po-Heng; et el." }, { "id": "https://authors.library.caltech.edu/records/ksnzx-brs73", "eprint_id": 46434, "eprint_status": "archive", "datestamp": "2023-08-20 01:51:46", "lastmod": "2023-10-26 19:44:48", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Radlauer-M-R", "name": { "family": "Radlauer", "given": "Madalyn R." }, "orcid": "0000-0002-3226-5340" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Bimetallic Zirconium Amine Bis(phenolate) Polymerization Catalysts: Enhanced Activity and Tacticity Control for Polyolefin Synthesis", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2014 American Chemical Society. ACS AuthorChoice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. \n\nReceived: June 9, 2014. Publication Date (Web): June 18, 2014. \n\nWe are grateful to Dow Chemical, Caltech, and the ACS PRF for\nfunding. We thank Dr. Mike Takase, Lawrence M. Henling, and\nEmily Tsui for crystallographic assistance. The Bruker KAPPA\nAPECII X-ray diffractometer was purchased via an NSF\nCRIF:MU award to Caltech (CHE-063-9094). The 400 MHz\nNMR spectrometer was purchased via an NIH award\n(RR027690).\n\nPublished - om500608j.pdf
Supplemental Material - om500608j_si_001.pdf
Supplemental Material - om500608j_si_002.cif
", "abstract": "Binucleating multidentate amine bis(phenolate) ligands with rigid terphenyl backbones were designed to support two zirconium centers locked in close proximity. Polymerizations of propylene or 1-hexene with the synthesized bimetallic precatalysts resulted in polymers with significantly higher isotacticity (up to 79% mmmm) in comparison to the stereoirregular polymers produced with previously reported C_s-symmetric monometallic analogues. The bimetallic precatalysts also display higher activity (up to 124 kg of poly(1-hexene) (mmol of Zr)^(\u22121) h^(\u20131)), in comparison to the monometallic analogues, and among the highest activities reported for nonmetallocene catalysts. The stereocontrol is consistent with a bimetallic mechanism involving remote steric interactions with the ligand sphere of the second metal center.", "date": "2014-07-14", "date_type": "published", "publication": "Organometallics", "volume": "33", "number": "13", "publisher": "American Chemical Society", "pagerange": "3247-3250", "id_number": "CaltechAUTHORS:20140623-105942813", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140623-105942813", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical" }, { "agency": "Caltech" }, { "agency": "American Chemical Society Petroleum Research Fund" }, { "agency": "NSF", "grant_number": "CHE-063-9094" }, { "agency": "NIH", "grant_number": "RR027690" } ] }, "doi": "10.1021/om500608j", "pmcid": "PMC4216186", "primary_object": { "basename": "om500608j_si_001.pdf", "url": "https://authors.library.caltech.edu/records/ksnzx-brs73/files/om500608j_si_001.pdf" }, "related_objects": [ { "basename": "om500608j_si_002.cif", "url": "https://authors.library.caltech.edu/records/ksnzx-brs73/files/om500608j_si_002.cif" }, { "basename": "om500608j.pdf", "url": "https://authors.library.caltech.edu/records/ksnzx-brs73/files/om500608j.pdf" } ], "resource_type": "article", "pub_year": "2014", "author_list": "Radlauer, Madalyn R. and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/r9d3f-cg942", "eprint_id": 55769, "eprint_status": "archive", "datestamp": "2023-08-19 23:59:57", "lastmod": "2023-10-20 23:09:18", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Synthesis and properties of heterometallic cluster models of biological and heterogeneous water oxidation catalysts", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2014 American Chemical Society.", "abstract": "Heterometallic clusters are found in biol. and heterogeneous water oxidn. catalysts, but the roles of different metal sites\nare currently not well understood. Targeting rational syntheses of models for these catalysts, triphenylbenzene moieties\nappended with pyridine and alkoxide donors were employed as multinucleating ligands for first- row transition metals.\nTrinuclear complexes were utilized as precursors to more elaborate metal oxide clusters. Tetranuclear complexes displaying\nMn_3M and Fe_3M motifs (M = Na^+, Ca^(2+), Sr^(2+), Zn^(2+), Sc, Y^(3+)) with varied no. of bridging oxo ligands were synthesized and\nstudied. The redn. potentials of these clusters span a window of over 1 V. With the pK of metal (M) aqua complex as a\nmeasure of Lewis acidity, structurally analogous series of clusters display linear dependence between redn. potential and\nacidity. Implications for the function of oxygen evolving catalysts will be discussed.", "date": "2014-03-16", "date_type": "published", "publication": "Abstracts of Papers of the American Chemical Society", "volume": "247", "publisher": "American Chemical Society", "pagerange": "519-INOR", "id_number": "CaltechAUTHORS:20150316-085508823", "issn": "0065-7727", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150316-085508823", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "resource_type": "article", "pub_year": "2014", "author_list": "Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/2qhrj-qd636", "eprint_id": 44518, "eprint_status": "archive", "datestamp": "2023-08-19 23:49:36", "lastmod": "2023-10-26 14:21:50", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Horak-K-T", "name": { "family": "Horak", "given": "Kyle T." } }, { "id": "Velian-A", "name": { "family": "Velian", "given": "Alexandra" } }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Arene non-innocence in dinuclear complexes of Fe, Co, and Ni supported by a para-terphenyl diphosphine", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2014 Royal Society of Chemistry. Received 30th January 2014, Accepted 28th February 2014. First published online 03 Mar 2014. We thank Lawrence M. Henling for crystallographic assistance. We are grateful to Caltech and NSF CAREER CHE-1151918 for funding. T.A. is a Sloan and Cottrell Fellow. The Bruker X-ray diffractometer was purchased via an NSF CRIF:MU award to Caltech, CHE-0639094.\n\nPublished - c4cc00838c.pdf
Supplemental Material - c4cc00838c1.pdf
Supplemental Material - c4cc00838c2.cif
", "abstract": "Cofacial Fe_2, Co_2, and Ni_2 complexes supported by a para-terphenyl diphosphine ligand were prepared. Central arene deplanarization and a \u03bc_2:(\u03b7^3,\u03b7^3) coordination mode suggest partial bisallyl character in the Fe_2 and Co_2 complexes. An oxidation induced shift in Fe_2\u2013arene binding highlights the non-innocent nature of the arene ligand.", "date": "2014-03-03", "date_type": "published", "publication": "Chemical Communications", "volume": "50", "number": "34", "publisher": "Royal Society of Chemistry", "pagerange": "4427-4429", "id_number": "CaltechAUTHORS:20140326-090813158", "issn": "1359-7345", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140326-090813158", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "NSF", "grant_number": "CHE-0639094" } ] }, "doi": "10.1039/C4CC00838C", "primary_object": { "basename": "c4cc00838c1.pdf", "url": "https://authors.library.caltech.edu/records/2qhrj-qd636/files/c4cc00838c1.pdf" }, "related_objects": [ { "basename": "c4cc00838c2.cif", "url": "https://authors.library.caltech.edu/records/2qhrj-qd636/files/c4cc00838c2.cif" }, { "basename": "c4cc00838c.pdf", "url": "https://authors.library.caltech.edu/records/2qhrj-qd636/files/c4cc00838c.pdf" } ], "resource_type": "article", "pub_year": "2014", "author_list": "Horak, Kyle T.; Velian, Alexandra; et el." }, { "id": "https://authors.library.caltech.edu/records/xwxgr-hdd80", "eprint_id": 45213, "eprint_status": "archive", "datestamp": "2023-08-19 23:40:44", "lastmod": "2023-10-26 17:52:22", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Martin-Diaconescu-V", "name": { "family": "Martin-Diaconescu", "given": "V." } }, { "id": "Serena-D", "name": { "family": "Serena", "given": "D." } }, { "id": "Gennari-M", "name": { "family": "Gennari", "given": "M." } }, { "id": "Gerey-B", "name": { "family": "Gerey", "given": "B." } }, { "id": "Duboc-C", "name": { "family": "Duboc", "given": "C." } }, { "id": "Collomb-M", "name": { "family": "Collomb", "given": "M." } }, { "id": "Tsui-Emily-Y", "name": { "family": "Tsui", "given": "E." }, "orcid": "0000-0001-6419-3954" }, { "id": "Kanady-J", "name": { "family": "Kanady", "given": "J." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "T." }, "orcid": "0000-0002-9692-7614" }, { "id": "Tran-Rosalie", "name": { "family": "Tran", "given": "R." } }, { "id": "Yano-Junko", "name": { "family": "Yano", "given": "J." }, "orcid": "0000-0001-6308-9071" }, { "id": "P\u00e9caut-J", "name": { "family": "P\u00e9caut", "given": "J." } } ] }, "title": "Application of X-ray Absorption (XAS) and Emission (XES) Spectroscopies to the Calcium Centers of PSII Oxygen Evolving Complex Structural Analogs", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2014 Springer. CONTROL ID: 1719403", "abstract": "The four-electron oxidation of water by photosynthetic organisms, carried out by the Oxygen Evolving Complex (OEC) of Photosystem II (PS II), is a process essential for aerobic life.", "date": "2014-03", "date_type": "published", "publication": "Journal of Biological Inorganic Chemistry", "volume": "19", "number": "S1", "publisher": "Springer", "pagerange": "S498", "id_number": "CaltechAUTHORS:20140425-085913641", "issn": "0949-8257", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140425-085913641", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1007/s00775-014-1095-8", "resource_type": "article", "pub_year": "2014", "author_list": "Martin-Diaconescu, V.; Serena, D.; et el." }, { "id": "https://authors.library.caltech.edu/records/a8kma-pba33", "eprint_id": 43592, "eprint_status": "archive", "datestamp": "2023-08-19 22:39:42", "lastmod": "2023-10-25 23:41:37", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Herbert-D-E", "name": { "family": "Herbert", "given": "David E." } }, { "id": "Lionetti-D", "name": { "family": "Lionetti", "given": "Davide" }, "orcid": "0000-0002-4937-886X" }, { "id": "Rittle-J", "name": { "family": "Rittle", "given": "Jonathan" } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Heterometallic Triiron-Oxo/Hydroxo Clusters: Effect of Redox-Inactive Metals", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2013 American Chemical Society.\n\nPublished In Issue December 26, 2013; Article ASAP December 16, 2013; Just Accepted Manuscript December 04, 2013; Received: October 13, 2013.\n\nThe authors declare no competing financial interest.\n\nThis work was supported by the California Institute of\nTechnology, the Searle Scholars Program, the NSF CAREER\nCHE-1151918 (T.A.), a Camille & Henry Dreyfus Environmental\nChemistry Fellowship (D.E.H.), and a Resnick\nSustainability Institute graduate fellowship (D.L.). T.A. is a\nSloan and Cottrell Fellow. We thank Larry M. Henling and Dr.\nMichael Takase for assistance with crystallography and Prof.\nJonas C. Peters for use of a M\u00f6ssbauer spectrometer. Collection\nof M\u00f6ssbauer data was made possible by use of an instrument\npurchased with funds from the National Science Foundation\nCenter for Chemical Innovation on Solar Fuels (CCI Solar,\nGrant CHE-1305124). The Bruker KAPPA APEXII X-ray\ndiffractometer was purchased via an NSF Chemistry Research\nInstrumentation award to Caltech (CHE-0639094). We\nacknowledge the Gordon and Betty Moore Foundation, the\nBeckman Institute, and the Sanofi-Aventis BRP at Caltech for\ntheir generous support of the Molecular Observatory at Caltech.\nOperations at SSRL are supported by the U.S. DOE and NIH.\n\nAccepted Version - nihms550402.pdf
Supplemental Material - ja4104974_si_001.pdf
Supplemental Material - ja4104974_si_002.zip
", "abstract": "A series of tetranuclear oxo/hydroxo clusters comprised of three Fe centers and a redox-inactive metal (M) of various charge is reported. Crystallographic\nstudies show an unprecedented Fe_3M(\u03bc_4-O)(\u03bc_2-OH) core\nthat remains intact upon changing M or the oxidation state\nof iron. Electrochemical studies reveal that the reduction\npotentials (E_(1/2)) span a window of 500 mV and depend\nupon the Lewis acidity of M. Using the pK_a of the M-aqua\ncomplex as a measure of Lewis acidity, these compounds\ndisplay a linear dependence between E1/2 and acidity, with\na slope of \u223c70 mV per pK_a unit. The current study of\n[Fe_3MO(OH)] and previous ones of [Mn_3MO_n] (n = 2,4)\nmoieties support the generality of the above relationship\nbetween the reduction potentials of heterometallic oxido\nclusters and the Lewis acidity of incorporated cations, as\napplied to clusters of different redox-active metals.", "date": "2013-12-26", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "135", "number": "51", "publisher": "American Chemical Society", "pagerange": "19075-19078", "id_number": "CaltechAUTHORS:20140130-144616034", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140130-144616034", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "Searle Scholars Program" }, { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Resnick Sustainability Institute" }, { "agency": "NSF", "grant_number": "CHE-0639094" }, { "agency": "Gordon and Betty Moore Foundation" } ] }, "local_group": { "items": [ { "id": "Resnick-Sustainability-Institute" }, { "id": "CCI-Solar-Fuels" } ] }, "doi": "10.1021/ja4104974", "pmcid": "PMC3953215", "primary_object": { "basename": "ja4104974_si_001.pdf", "url": "https://authors.library.caltech.edu/records/a8kma-pba33/files/ja4104974_si_001.pdf" }, "related_objects": [ { "basename": "ja4104974_si_002.zip", "url": "https://authors.library.caltech.edu/records/a8kma-pba33/files/ja4104974_si_002.zip" }, { "basename": "nihms550402.pdf", "url": "https://authors.library.caltech.edu/records/a8kma-pba33/files/nihms550402.pdf" } ], "resource_type": "article", "pub_year": "2013", "author_list": "Herbert, David E.; Lionetti, Davide; et el." }, { "id": "https://authors.library.caltech.edu/records/d1eda-73851", "eprint_id": 43513, "eprint_status": "archive", "datestamp": "2023-08-19 22:36:56", "lastmod": "2023-10-25 23:37:06", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Tsui-Emily-Y", "name": { "family": "Tsui", "given": "Emily Y." }, "orcid": "0000-0001-6419-3954" }, { "id": "Kanady-J-S", "name": { "family": "Kanady", "given": "Jacob S." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Synthetic Cluster Models of Biological and Heterogeneous Manganese Catalysts for O_2 Evolution", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2013 American Chemical Society. \n\nReceived: September 2, 2013; Published: December 16, 2013. \n\nWe thank the California Institute of Technology, the Searle Scholars Program, NSF CAREER Grant CHE-1151918, NIH R01 GM102687A (to T.A.), a Sandia Campus Executive Fellowship (to E.Y.T.), and NSF Graduate Fellowships (to E.Y.T. and J.S.K.) for financial support. We are grateful to collaborators for insightful discussions and to colleagues and co-workers for a stimulating environment in which to do science at Caltech.\n\nAccepted Version - nihms-550513.pdf
", "abstract": "Artificial photosynthesis has emerged as an important strategy toward clean and renewable fuels. Catalytic\noxidation of water to O_2 remains a significant challenge in this context. A mechanistic understanding of currently known heterogeneous and biological catalysts at a molecular level is\nhighly desirable for fundamental reasons as well as for the\nrational design of practical catalysts. This Award Article\ndiscusses recent efforts in synthesizing structural models of the\noxygen-evolving complex of photosystem II. These structural\nmotifs are also related to heterogeneous mixed-metal oxide catalysts. A stepwise synthetic methodology was developed toward\nachieving the structural complexity of the targeted active sites. A geometrically restricted multinucleating ligand, but with labile\ncoordination modes, was employed for the synthesis of low-oxidation-state trimetallic species. These precursors were elaborated\nto site-differentiated tetrametallic complexes in high oxidation states. This methodology has allowed for structure\u2212reactivity\nstudies that have offered insight into the effects of different components of the clusters. Mechanistic aspects of oxygen-atom\ntransfer and incorporation from water have been interrogated. Significantly, a large and systematic effect of redox-inactive metals\non the redox properties of these clusters was discovered. With the pK_a value of the redox-inactive metal\u2212aqua complex as a\nmeasure of the Lewis acidity, structurally analogous clusters display a linear dependence between the reduction potential and\nacidity; each pK_a unit shifts the potential by ca. 90 mV. Implications for the function of the biological and heterogeneous catalysts\nare discussed.", "date": "2013-12-16", "date_type": "published", "publication": "Inorganic Chemistry", "volume": "52", "number": "24", "publisher": "American Chemical Society", "pagerange": "13833-13848", "id_number": "CaltechAUTHORS:20140124-132431040", "issn": "0020-1669", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140124-132431040", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "Searle Scholars Program" }, { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "NIH", "grant_number": "R01 GM102687A" }, { "agency": "Sandia National Laboratories" }, { "agency": "NSF Graduate Research Fellowship" } ] }, "doi": "10.1021/ic402236f", "pmcid": "PMC3917504", "primary_object": { "basename": "nihms-550513.pdf", "url": "https://authors.library.caltech.edu/records/d1eda-73851/files/nihms-550513.pdf" }, "resource_type": "article", "pub_year": "2013", "author_list": "Tsui, Emily Y.; Kanady, Jacob S.; et el." }, { "id": "https://authors.library.caltech.edu/records/hh7d3-c7c77", "eprint_id": 42389, "eprint_status": "archive", "datestamp": "2023-08-19 22:32:02", "lastmod": "2023-10-25 15:53:36", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Suseno-S", "name": { "family": "Suseno", "given": "Sandy" } }, { "id": "Horak-K-T", "name": { "family": "Horak", "given": "Kyle T." } }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Trinuclear Nickel Complexes with Metal\u2013Arene Interactions Supported by Tris- and Bis(phosphinoaryl)benzene Frameworks", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2013 American Chemical Society. \n\nReceived: October 5, 2013; Published: November 4, 2013. \n\nWe are grateful to Caltech, the NSF CAREER CHE-1151918,\nand the Dow Chemical Company Graduate Student Fellowship\n(S.S.) for funding. We thank Dr. Mike Takase, Lawrence M.\nHenling, and Emily Y. Tsui for crystallographic assistance, and Madalyn R. Radlauer for NMR spectroscopy assistance. The\nBruker KAPPA APEXII X-ray diffractometer was purchased via\nan NSF CRIF:MU award to Caltech, CHE-063-9094. The\n500 MHz NMR spectrometer was purchased via an NIH award,\nRR027690.\n\nAccepted Version - nihms-537987.pdf
Supplemental Material - om400976x_si_001.pdf
Supplemental Material - om400976x_si_002.zip
", "abstract": "Triphosphine and diphosphine ligands with backbones designed to facilitate metal\u2013arene interactions were employed to support multinuclear Ni complexes. Di- and trinuclear metal complexes supported by a triphosphine containing a triarylbenzene linker display diverse metal\u2013arene binding modes. Multinuclear Ni halide complexes were isolated with strongly interacting metal centers bound to opposite faces of the coordinated arene. Upon reaction of the trinickel diiodide complex 2 with disodium tetracarbonylferrate, a cofacial triangulo nickel(0) complex, 4, was isolated. The Ni^(0)_(3) cluster motif can also be supported by a para-terphenyl diphosphine, where a terminal carbon monoxide ligand replaces the third phosphine donor. All multinuclear complexes feature strong metal\u2013arene interactions, demonstrating the use of an arene as a versatile ligand design element for small clusters.", "date": "2013-12-09", "date_type": "published", "publication": "Organometallics", "volume": "32", "number": "23", "publisher": "American Chemical Society", "pagerange": "6883-6886", "id_number": "CaltechAUTHORS:20131112-113306864", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131112-113306864", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "Dow Chemical Company" }, { "agency": "NSF", "grant_number": "CHE-063-9094" }, { "agency": "NIH", "grant_number": "RR027690" }, { "agency": "Caltech" } ] }, "doi": "10.1021/om400976x", "pmcid": "PMC3920585", "primary_object": { "basename": "nihms-537987.pdf", "url": "https://authors.library.caltech.edu/records/hh7d3-c7c77/files/nihms-537987.pdf" }, "related_objects": [ { "basename": "om400976x_si_001.pdf", "url": "https://authors.library.caltech.edu/records/hh7d3-c7c77/files/om400976x_si_001.pdf" }, { "basename": "om400976x_si_002.zip", "url": "https://authors.library.caltech.edu/records/hh7d3-c7c77/files/om400976x_si_002.zip" } ], "resource_type": "article", "pub_year": "2013", "author_list": "Suseno, Sandy; Horak, Kyle T.; et el." }, { "id": "https://authors.library.caltech.edu/records/jhete-x2505", "eprint_id": 43959, "eprint_status": "archive", "datestamp": "2023-08-22 10:56:20", "lastmod": "2023-10-26 00:02:46", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Herbert-D-E", "name": { "family": "Herbert", "given": "David E." } }, { "id": "Lara-N-C", "name": { "family": "Lara", "given": "Nadia C." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Arene C-H Amination at Nickel in Terphenyl\u2013Diphosphine Complexes with Labile Metal\u2013Arene Interactions", "ispublished": "pub", "full_text_status": "public", "keywords": "amination; arenes; C H activation; group transfer; insertion\nreactions", "note": "\u00a9 2013 Wiley-VCH Verlag GmbH & Co. Received: July 2, 2013. Article first published online: 14 Oct 2013. The authors thank Larry M. Henling for invaluable crystallographic assistance, the late Dr. Michael W. Day for solving the crystal structure of 4,\nand Caltech for generous funding and support. The Bruker KAPPA APEXII X-Ray diffractometer was purchased via an NSF CRIF:MU award to Caltech (CHE-0639094). The Gordon and Betty Moore Foundation, the Beckman Institute and the Sanofi-Aventis BRP are thanked for their support of the Molecular Observatory at Caltech and the SSRL beamline, operated for the DOE and supported by its Office of Biological and Environmental Research and by the NIH and NIGMS (P41 M103393) and the NCRR (P41RR001209).\n\nAccepted Version - nihms535419.pdf
Supplemental Material - chem_201302539_sm_miscellaneous_information.pdf
", "abstract": "The meta-terphenyl diphosphine, m-P_2, 1, was utilized to support Ni centers in the oxidation states 0, I, and II. A series of complexes bearing different substituents or ligands at Ni was prepared to investigate the dependence of metal\u2013arene interactions on oxidation state and substitution at the metal center. Complex (m-P_2)Ni (2) shows strong Ni^0\u2013arene interactions involving the central arene ring of the terphenyl ligand both in solution and the solid state. These interactions are significantly less pronounced in Ni^0 complexes bearing L-type ligands (2-L: L=CH_3CN, CO, Ph_2CN_2), Ni^IX complexes (3-X: X=Cl, BF_4, N_3, N_3B(C_6F_5)_3), and [(m-P_2)Ni^(II)Cl_2] (4). Complex 2 reacts with substrates, such as diphenyldiazoalkane, sulfur ylides (Ph_2=CH_2), organoazides (RN_3: R=para-C_6H_4OMe, para-C_6H_4CF_3, 1-adamantyl), and N_2O with the locus of observed reactivity dependent on the nature of the substrate. These reactions led to isolation of an \u03b7^1-diphenyldiazoalkane adduct (2-Ph_2CN_2), methylidene insertion into a Ni-P bond followed by rearrangement of a nickel-bound phosphorus ylide (5) to a benzylphosphine (6), Staudinger oxidation of the phosphine arms, and metal-mediated nitrene insertion into an arene C-H bond of 1, all derived from the same compound (2). Hydrogen-atom abstraction from a Ni^I\u2013amide (9) and the resulting nitrene transfer supports the viability of Ni\u2013imide intermediates in the reaction of 1 with 1-azido-arenes.", "date": "2013-11-25", "date_type": "published", "publication": "Chemistry-A European Journal", "volume": "19", "number": "48", "publisher": "Wiley", "pagerange": "16453-16460", "id_number": "CaltechAUTHORS:20140224-152357603", "issn": "0947-6539", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140224-152357603", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "NSF", "grant_number": "CHE-0639094" }, { "agency": "Gordon and Betty Moore Foundation" }, { "agency": "Caltech Beckman Institute" }, { "agency": "Sanofi-Aventis" }, { "agency": "Caltech Molecular Observatory" }, { "agency": "Department of Energy (DOE)" }, { "agency": "NIH", "grant_number": "P41 M103393" }, { "agency": "NIH", "grant_number": "P41RR001209" } ] }, "doi": "10.1002/chem.201302539", "pmcid": "PMC3897266", "primary_object": { "basename": "nihms535419.pdf", "url": "https://authors.library.caltech.edu/records/jhete-x2505/files/nihms535419.pdf" }, "related_objects": [ { "basename": "chem_201302539_sm_miscellaneous_information.pdf", "url": "https://authors.library.caltech.edu/records/jhete-x2505/files/chem_201302539_sm_miscellaneous_information.pdf" } ], "resource_type": "article", "pub_year": "2013", "author_list": "Herbert, David E.; Lara, Nadia C.; et el." }, { "id": "https://authors.library.caltech.edu/records/jwz66-46c69", "eprint_id": 42883, "eprint_status": "archive", "datestamp": "2023-08-19 21:59:12", "lastmod": "2023-10-25 23:07:31", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lin-Sibo", "name": { "family": "Lin", "given": "Sibo" }, "orcid": "0000-0001-5922-6694" }, { "id": "Herbert-D-E", "name": { "family": "Herbert", "given": "David E." } }, { "id": "Velian-A", "name": { "family": "Velian", "given": "Alexandra" } }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Dipalladium(I) Terphenyl Diphosphine Complexes as Models for\n Two-Site Adsorption and Activation of Organic Molecules", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2013 American Chemical Society. Received: July 1, 2013. Publication Date (Web): September 25, 2013. We thank Aaron Sattler for helpful discussion and Lawrence M.\nHenling and Jens Kaiser for assistance with collection of\ncrystallographic data. We are grateful to Caltech, BP, NSF\nCAREER CHE-1151918, and NSF GRFP (S.L.) for funding.\nWe thank the Gordon and Betty Moore Foundation for their\ngenerous support of the Molecular Observatory at Caltech. The\nBruker KAPPA APEXII X-ray diffractometer was purchased via\nan NSF CRIF:MU Award to Caltech (Grant No. CHE-0639094). The 400 MHz NMR spectrometer was purchased\nvia an NIH award (No. RR027690).\nThe authors declare no competing financial interest\n\nAccepted Version - nihms-531360.pdf
Supplemental Material - ja406696k_si_001.pdf
Supplemental Material - ja406696k_si_002.zip
", "abstract": "A para-terphenyl diphosphine was employed to support a dipalladium(I) moiety. Unlike previously reported dipalladium(I) species, the present system provides a single molecular hemisphere for binding of ligands across two metal centers, enabling the characterization and comparison of the binding of a wide variety of saturated and unsaturated organic molecules. The dipalladium(I) terphenyl diphosphine toluene-capped complex was synthesized from a dipalladium(I) hexaacetonitrile precursor in the presence of toluene. The palladium centers display interactions with the \u03c0-systems of the central ring of the terphenyl unit and that of the toluene. Exchange of toluene for anisole, 1,3-butadiene, 1,3-cyclohexadiene, thiophenes, pyrroles, or furans resulted in well-defined \u03c0-bound complexes which were studied by crystallography, nuclear magnetic resonance (NMR) spectroscopy, and density functional theory. Structural characterization shows that the interactions of the dipalladium unit with the central arene of the diphosphine does not vary significantly in this series allowing for a systematic comparison of the binding of the incoming ligands to the dipalladium moiety. Several of the complexes exhibit rare \u03bc\u2013\u03b7^2:\u03b7^2 or \u03bc\u2013\u03b7^2:\u03b7^1(O or S) bridging motifs. Hydrogenation of the thiophene and benzothiophene adducts was demonstrated to proceed at room temperature. The relative binding strength of the neutral ligands was determined by competition experiments monitored by NMR spectroscopy. The relative equilibrium constants for ligand substitution span over 13 orders of magnitude. This represents the most comprehensive analysis to date of the relative binding of heterocycles and unsaturated ligands to bimetallic sites. Binding interactions were computationally studied with electrostatic potentials and molecular orbital analysis. Anionic ligands were also demonstrated to form \u03c0-bound complexes.", "date": "2013-10-23", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "135", "number": "42", "publisher": "American Chemical Society", "pagerange": "15830-15840", "id_number": "CaltechAUTHORS:20131206-095913163", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131206-095913163", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "Gordon and Betty Moore Foundation" }, { "agency": "NSF", "grant_number": "CHE-0639094" }, { "agency": "NIH", "grant_number": "RR027690" }, { "agency": "Caltech" }, { "agency": "BP" } ] }, "doi": "10.1021/ja406696k", "pmcid": "PMC3851319", "primary_object": { "basename": "ja406696k_si_001.pdf", "url": "https://authors.library.caltech.edu/records/jwz66-46c69/files/ja406696k_si_001.pdf" }, "related_objects": [ { "basename": "ja406696k_si_002.zip", "url": "https://authors.library.caltech.edu/records/jwz66-46c69/files/ja406696k_si_002.zip" }, { "basename": "nihms-531360.pdf", "url": "https://authors.library.caltech.edu/records/jwz66-46c69/files/nihms-531360.pdf" } ], "resource_type": "article", "pub_year": "2013", "author_list": "Lin, Sibo; Herbert, David E.; et el." }, { "id": "https://authors.library.caltech.edu/records/7gsyk-74288", "eprint_id": 41737, "eprint_status": "archive", "datestamp": "2023-08-19 21:47:22", "lastmod": "2023-10-25 14:42:48", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kanady-J-S", "name": { "family": "Kanady", "given": "Jacob S." } }, { "id": "Tran-Rosalie", "name": { "family": "Tran", "given": "Rosalie" } }, { "id": "Stull-J-A", "name": { "family": "Stull", "given": "Jamie A." } }, { "id": "Lu-Luo", "name": { "family": "Lu", "given": "Luo" } }, { "id": "Stich-T-A", "name": { "family": "Stich", "given": "Troy A." }, "orcid": "0000-0003-0710-1456" }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Yano-Junko", "name": { "family": "Yano", "given": "Junko" }, "orcid": "0000-0001-6308-9071" }, { "id": "Britt-R-D", "name": { "family": "Britt", "given": "R. David" }, "orcid": "0000-0003-0889-8436" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Role of oxido incorporation and ligand lability in expanding redox accessibility of structurally related Mn4 clusters", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2013 Royal Society of Chemistry.\n\nReceived 20th May 2013; Accepted 18th July 2013.\n\nWe are grateful to California Institute of Technology, the Searle Scholars Program, an NSF CAREER (CHE-1151918) award (TA), the Rose Hill Foundation, and the NSF GRFP (J.S.K.) for funding. We thank L. M. Henling for assistance with crystallography. The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF CRIF:MU award to Caltech (CHE-0639094). We acknowledge the Gordon and Betty Moore Foundation, the Beckman Institute, and the Sano\ue103-Aventis BRP for their support of the Molecular Observatory at Caltech. The work carried out by RDB was funded by the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences of the U.S. Department of Energy (DE-FG02-11ER16282). SSRL is operated by Stanford University for the DOE and supported by its Office of Biological and Environmental Research, and by the NIH, NIGMS (including P41GM103393) and the NCRR (P41RR001209). X-ray spectroscopy studies were supported by the NIH (F32GM100595 to R.T.) and by the Director of the Office of Basic Energy Science, Division of Chemical Sciences, Geosciences, and Biosciences, DOE\n(DE-AC02-05CH11231 to J.Y.).\n\nPublished - c3sc51406d.pdf
", "abstract": "Photosystem II supports four manganese centers through nine oxidation states from manganese(II) during assembly through to the most oxidized state before O_2 formation and release. The protein-based carboxylate and imidazole ligands allow for significant changes of the coordination environment during the incorporation of hydroxido and oxido ligands upon oxidation of the metal centers. We report the synthesis and characterization of a series of tetramanganese complexes in four of the six oxidation states from Mn^(II)_(3)Mn^III to Mn^(III)_(2)Mn^(IV)_2 with the same ligand framework (L) by incorporating four oxido ligands. A 1,3,5-triarylbenzene framework appended with six pyridyl and three alkoxy groups was utilized along with three acetate anions to access tetramanganese complexes, Mn_(4)O_x, with x = 1, 2, 3, and 4. Alongside two previously reported complexes, four new clusters in various states were isolated and characterized by crystallography, and four were observed electrochemically, thus accessing the eight oxidation states from Mn^(II)_4 to Mn^(III)Mn^(IV)_3. This structurally related series of compounds was characterized by EXAFS, XANES, EPR, magnetism, and cyclic voltammetry. Similar to the ligands in the active site of the protein, the ancillary ligand (L) is preserved throughout the series and changes its binding mode between the low and high oxido-content clusters. Implications for the rational assembly and properties of high oxidation state metal\u2013oxido clusters are presented.", "date": "2013-10-01", "date_type": "published", "publication": "Chemical Science", "volume": "4", "number": "10", "publisher": "Royal Society of Chemistry", "pagerange": "3986-3996", "id_number": "CaltechAUTHORS:20131008-104102301", "issn": "2041-6520", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131008-104102301", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "Searle Scholars Program" }, { "agency": "Rose Hill Foundation" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-FG02- 11ER16282" }, { "agency": "NIH", "grant_number": "P41GM103393" }, { "agency": "NIH", "grant_number": "P41RR001209" }, { "agency": "NIH", "grant_number": "F32GM100595" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-05CH11231" }, { "agency": "NSF", "grant_number": "CHE-1151918" } ] }, "doi": "10.1039/C3SC51406D", "pmcid": "PMC3806640", "primary_object": { "basename": "c3sc51406d.pdf", "url": "https://authors.library.caltech.edu/records/7gsyk-74288/files/c3sc51406d.pdf" }, "resource_type": "article", "pub_year": "2013", "author_list": "Kanady, Jacob S.; Tran, Rosalie; et el." }, { "id": "https://authors.library.caltech.edu/records/09fvp-0g015", "eprint_id": 43685, "eprint_status": "archive", "datestamp": "2023-08-22 10:04:34", "lastmod": "2023-10-25 23:46:46", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kelley-P", "name": { "family": "Kelley", "given": "Paul" } }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Hydrogen Evolution Catalyzed by Aluminum-Bridged Cobalt Diglyoximate Complexes", "ispublished": "pub", "full_text_status": "public", "keywords": "Hydrogen; Cobalt; Reduction; Redox chemistry; Multimetallic complexes", "note": "\u00a9 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.\n\nReceived: March 7, 2013; Published Online: May 14, 2013.\n\nLawrence M. Henling is thanked for collection of the XRD data and preliminary structural analysis. The authors are grateful to the\nCalifornia Institute of Technology for funding. The Bruker KAPPA APEXII X-ray diffractometer was purchased through a National\nScience Foundation (NSF) CRIF:MU award to Caltech (CHE-0639094).\n\nSupplemental Material - ejic_201300309_sm_miscellaneous_information.pdf
", "abstract": "The syntheses of several cobalt diglyoximate complexes connected by one or two aluminum bridges are described. The aluminum centers are supported by tunable tetradentate diamine bisphenoxide ligands. Electrochemical investigations revealed that the number of aluminum bridges and the nature of the substituents on the phenoxide ligands significantly affect the cobalt reduction potentials. The present aluminum\u2013cobalt compounds are electrocatalysts for proton reduction to hydrogen at potentials negative relative to those of the boron- and proton-bridged analogs. The reported synthetic strategies allow modulation of the reduction potentials and the secondary coordination sphere interactions by tuning the ancillary ligands bound to aluminum.", "date": "2013-08-06", "date_type": "published", "publication": "European Journal of Inorganic Chemistry", "volume": "2013", "number": "22-23", "publisher": "Wiley-VCH Verlag", "pagerange": "3840-3845", "id_number": "CaltechAUTHORS:20140206-083918513", "issn": "1434-1948", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140206-083918513", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "NSF", "grant_number": "CHE-0639094" } ] }, "doi": "10.1002/ejic.201300309", "primary_object": { "basename": "ejic_201300309_sm_miscellaneous_information.pdf", "url": "https://authors.library.caltech.edu/records/09fvp-0g015/files/ejic_201300309_sm_miscellaneous_information.pdf" }, "resource_type": "article", "pub_year": "2013", "author_list": "Kelley, Paul; Day, Michael W.; et el." }, { "id": "https://authors.library.caltech.edu/records/n6fjy-pbm07", "eprint_id": 41114, "eprint_status": "archive", "datestamp": "2023-08-22 09:38:39", "lastmod": "2023-10-24 23:28:12", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Tsui-Emily-Y", "name": { "family": "Tsui", "given": "Emily Y." }, "orcid": "0000-0001-6419-3954" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Reduction potentials of heterometallic manganese-oxido cubane complexes modulated by redox-inactive metals", "ispublished": "pub", "full_text_status": "public", "keywords": "electrochemistry; heterometallic complexes; manganese clusters; model complexes; photosynthesis", "note": "\u00a9 2013 National Academy of Sciences.\n\nEdited by Harry B. Gray, California Institute of Technology, Pasadena, CA, and approved May 3, 2013 (received for review February 11, 2013).\n\nPublished online before print June 6, 2013.\n\nWe thank L. M. Henling for assistance with crystallography.\nThis work was supported by the California Institute of Technology,\nthe Searle Scholars Program, the National Science Foundation (NSF) CAREER CHE-1151918 (to T.A.), and a Sandia Campus Executive Fellowship (to E.Y.T.).\nThe Bruker KAPPA APEXII X-ray difractometer was purchased via an NSF\nChemistry Research Instrumentation award to the California Institute of\nTechnology (CHE-0639094).\n\nAuthor contributions: E.Y.T. and T.A. designed research; E.Y.T. performed research; E.Y.T.\nand T.A. analyzed data; and E.Y.T. and T.A. wrote the paper.\n\nThe authors declare no conflict of interest.\n\nThis article is a PNAS Direct Submission.\n\nData deposition: The atomic coordinates have been deposited in the Cambridge Crystallographic\nData Centre database, www.ccdc.cam.ac.uk/data_request/cif (accession nos.\nCCDC 923216\u2013923219).\n\nPublished - PNAS-2013-Tsui-10084-8.pdf
Supplemental Material - pnas.201302677SI.pdf
Supplemental Material - sd01.txt
", "abstract": "Understanding the effect of redox-inactive metals on the properties of biological and heterogeneous water oxidation catalysts is important both fundamentally and for improvement of future catalyst designs. In this work, heterometallic manganese\u2013oxido cubane clusters [MMn_3O_4] (M = Sr^(2+), Zn^(2+), Sc^(3+), Y^(3+)) structurally relevant to the oxygen-evolving complex (OEC) of photosystem II were prepared and characterized. The reduction potentials of these clusters and other related mixed metal manganese\u2013tetraoxido complexes are correlated with the Lewis acidity of the apical redox-inactive metal in a manner similar to a related series of heterometallic manganese\u2013dioxido clusters. The redox potentials of the [SrMn_3O_4] and [CaMn_3O_4] clusters are close, which is consistent with the observation that the OEC is functional only with one of these two metals. Considering our previous studies of [MMn_3O_2] moieties, the present results with more structurally accurate models of the OEC ([MMn_3O_4]) suggest a general relationship between the reduction potentials of heterometallic oxido clusters and the Lewis acidities of incorporated cations that applies to diverse structural motifs. These findings support proposals that one function of calcium in the OEC is to modulate the reduction potential of the cluster to allow electron transfer.", "date": "2013-06-18", "date_type": "published", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "volume": "110", "number": "25", "publisher": "National Academy of Sciences", "pagerange": "10084-10088", "id_number": "CaltechAUTHORS:20130905-105217468", "issn": "0027-8424", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130905-105217468", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "Searle Scholars Program" }, { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "Sandia Campus Executive Fellowship" }, { "agency": "NSF Chemistry Research Instrumentation Award", "grant_number": "CHE-0639094" } ] }, "doi": "10.1073/pnas.1302677110", "pmcid": "PMC3690856", "primary_object": { "basename": "PNAS-2013-Tsui-10084-8.pdf", "url": "https://authors.library.caltech.edu/records/n6fjy-pbm07/files/PNAS-2013-Tsui-10084-8.pdf" }, "related_objects": [ { "basename": "pnas.201302677SI.pdf", "url": "https://authors.library.caltech.edu/records/n6fjy-pbm07/files/pnas.201302677SI.pdf" }, { "basename": "sd01.txt", "url": "https://authors.library.caltech.edu/records/n6fjy-pbm07/files/sd01.txt" } ], "resource_type": "article", "pub_year": "2013", "author_list": "Tsui, Emily Y. and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/2fjba-r6c61", "eprint_id": 39758, "eprint_status": "archive", "datestamp": "2023-08-19 20:24:39", "lastmod": "2023-10-24 17:10:00", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Suseno-S", "name": { "family": "Suseno", "given": "Sandy" } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Intramolecular Arene C\u2212H to C\u2212P Functionalization Mediated by\n Nickel(II) and Palladium(II)", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2013 American Chemical Society.\n\nReceived: May 14, 2013; Published: May 23, 2013.\n\nThis work was supported by the California Institute of\nTechnology and the Dow Chemical Company Graduate Student Fellowship (S.S.) for funding. We thank Lawrence M. Henling, Emily Y. Tsui, and David E. Herbert for crystallographic assistance. The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF CRIF:MU award to Caltech (CHE-063-9094). The 400 MHz NMR spectrometer was purchased via an NIH award (RR027690).\n\nAccepted Version - nihms484838.pdf
Supplemental Material - om400424a_si_001.pdf
Supplemental Material - om400424a_si_002.zip
", "abstract": "A tris(phosphine) ligand with a triarylbenzene backbone was employed to support mono-nickel(II) and -palladium(II) complexes. Two phosphine arms coordinated to the metal center, while the third phosphine was found to form a C\u2013P bond with dearomatization of the central arene. Deprotonation effected the rearomatization of the central ring and metal reduction from M(II) to M(0). The overall conversion corresponds to a functionalization of an unactivated arene C\u2013H bond to a C\u2013P bond. This transformation represents a rare type of mechanism of C\u2013H functionalization, facilitated by the interactions of the group 10 metal with the arene \u03c0 system. This conversion is reminiscent of and expands the scope of recently reported intramolecular rearrangements of biaryl phosphine ligands common in group 10 catalysis.", "date": "2013-06-10", "date_type": "published", "publication": "Organometallics", "volume": "32", "number": "11", "publisher": "American Chemical Society", "pagerange": "3161-3164", "id_number": "CaltechAUTHORS:20130805-101207288", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130805-101207288", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "Dow Chemical Company" }, { "agency": "NSF", "grant_number": "CHE-063-9094" }, { "agency": "NIH", "grant_number": "RR027690" } ] }, "doi": "10.1021/om400424a", "pmcid": "PMC3811949", "primary_object": { "basename": "om400424a_si_002.zip", "url": "https://authors.library.caltech.edu/records/2fjba-r6c61/files/om400424a_si_002.zip" }, "related_objects": [ { "basename": "nihms484838.pdf", "url": "https://authors.library.caltech.edu/records/2fjba-r6c61/files/nihms484838.pdf" }, { "basename": "om400424a_si_001.pdf", "url": "https://authors.library.caltech.edu/records/2fjba-r6c61/files/om400424a_si_001.pdf" } ], "resource_type": "article", "pub_year": "2013", "author_list": "Suseno, Sandy and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/rac4c-hra19", "eprint_id": 38427, "eprint_status": "archive", "datestamp": "2023-08-19 19:14:19", "lastmod": "2023-10-23 20:09:31", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Tsui-Emily-Y", "name": { "family": "Tsui", "given": "Emily Y." }, "orcid": "0000-0001-6419-3954" }, { "id": "Tran-Rosalie", "name": { "family": "Tran", "given": "Rosalie" } }, { "id": "Yano-Junko", "name": { "family": "Yano", "given": "Junko" }, "orcid": "0000-0001-6308-9071" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Redox-inactive metals modulate the reduction potential in heterometallic manganese\u2013oxido clusters", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2013 Macmillan Publishers Limited. \n\nReceived 29 August 2012. Accepted 22 January 2013. Published online 03 March 2013. \n\nThis work was supported by the California Institute of Technology, the Searle Scholars Program, an NSF CAREER award (CHE-1151918 to T.A.) and the NSF Graduate Research\nFellowship Program (to E.Y.T.). The authors thank L.M. Henling and D.E. Herbert for assistance with crystallography, and P-H. Lin for assistance with magnetic susceptibility studies. The Bruker KAPPA APEXII X-ray diffractometer was purchased with an NSF Chemistry Research Instrumentation award to Caltech (CHE-0639094). The X-ray\nspectroscopy work was supported by the NIH (grant no. F32GM100595 to R.T.) and by the Director of the Office of Basic Energy Science (OBES), Division of Chemical Sciences,\nGeosciences, and Biosciences, DOE (contract no. DE-AC02-05CH11231 to J.Y.). Synchrotron facilities were provided by the Stanford Synchrotron Radiation Lightsource\n(SSRL), operated by the DOE, OBER. The authors declare no competing financial interests. \nAuthor contributions:\nE.Y.T. and T.A. designed the research. E.Y.T. and R.T. performed the experiments. R.T. and\nJ.Y. provided XANES characterization. E.Y.T., R.T., J.Y. and T.A. analysed data. E.Y.T. and\nT.A. wrote the paper.\n\nAccepted Version - nihms438373.pdf
Supplemental Material - nchem.1578-s1.pdf
Supplemental Material - nchem.1578-s2.cif
Supplemental Material - nchem.1578-s3.cif
Supplemental Material - nchem.1578-s4.cif
Supplemental Material - nchem.1578-s5.cif
Supplemental Material - nchem.1578-s6.cif
Supplemental Material - nchem.1578-s7.cif
Supplemental Material - nchem.1578-s8.cif
Supplemental Material - nchem.1578-s9.cif
", "abstract": "Redox-inactive metals are found in biological and heterogeneous water oxidation catalysts, but, at present, their roles in catalysis are not well understood. Here, we report a series of high-oxidation-state tetranuclear-dioxido clusters comprising three manganese centres and a redox-inactive metal (M). Crystallographic studies show an unprecedented Mn_3M(\u00b5_4-O)(\u00b5_2-O) core that remains intact on changing M or the manganese oxidation state. Electrochemical studies reveal that the reduction potentials span a window of 700 mV and are dependent on the Lewis acidity of the second metal. With the pK_a of the redox-inactive metal\u2013aqua complex as a measure of Lewis acidity, these compounds demonstrate a linear dependence between reduction potential and acidity with a slope of \u223c100 mV per pK_a unit. The Sr^(2+) and Ca^(2+) compounds show similar potentials, an observation that correlates with the behaviour of the oxygen-evolving complex of photosystem II, which is active only if one of these two metals is present.", "date": "2013-04", "date_type": "published", "publication": "Nature Chemistry", "volume": "5", "number": "4", "publisher": "Nature Publishing Group", "pagerange": "293-299", "id_number": "CaltechAUTHORS:20130510-131434222", "issn": "1755-4330", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130510-131434222", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "Searle Scholars Program" }, { "agency": "NSF", "grant_number": "CHE-1151918" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "NSF", "grant_number": "CHE-0639094" }, { "agency": "NIH Postdoctoral Fellowship", "grant_number": "F32GM100595" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-05CH11231" } ] }, "doi": "10.1038/NCHEM.1578", "pmcid": "PMC3654670", "primary_object": { "basename": "nihms438373.pdf", "url": "https://authors.library.caltech.edu/records/rac4c-hra19/files/nihms438373.pdf" }, "related_objects": [ { "basename": "nchem.1578-s1.pdf", "url": "https://authors.library.caltech.edu/records/rac4c-hra19/files/nchem.1578-s1.pdf" }, { "basename": "nchem.1578-s3.cif", "url": "https://authors.library.caltech.edu/records/rac4c-hra19/files/nchem.1578-s3.cif" }, { "basename": "nchem.1578-s4.cif", "url": "https://authors.library.caltech.edu/records/rac4c-hra19/files/nchem.1578-s4.cif" }, { "basename": "nchem.1578-s7.cif", "url": "https://authors.library.caltech.edu/records/rac4c-hra19/files/nchem.1578-s7.cif" }, { "basename": "nchem.1578-s8.cif", "url": "https://authors.library.caltech.edu/records/rac4c-hra19/files/nchem.1578-s8.cif" }, { "basename": "nchem.1578-s2.cif", "url": "https://authors.library.caltech.edu/records/rac4c-hra19/files/nchem.1578-s2.cif" }, { "basename": "nchem.1578-s5.cif", "url": "https://authors.library.caltech.edu/records/rac4c-hra19/files/nchem.1578-s5.cif" }, { "basename": "nchem.1578-s6.cif", "url": "https://authors.library.caltech.edu/records/rac4c-hra19/files/nchem.1578-s6.cif" }, { "basename": "nchem.1578-s9.cif", "url": "https://authors.library.caltech.edu/records/rac4c-hra19/files/nchem.1578-s9.cif" } ], "resource_type": "article", "pub_year": "2013", "author_list": "Tsui, Emily Y.; Tran, Rosalie; et el." }, { "id": "https://authors.library.caltech.edu/records/emrvk-3ss86", "eprint_id": 37924, "eprint_status": "archive", "datestamp": "2023-08-19 19:02:39", "lastmod": "2023-10-23 19:32:53", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Radlauer-M-R", "name": { "family": "Radlauer", "given": "Madalyn R." }, "orcid": "0000-0002-3226-5340" }, { "id": "Buckley-A-K", "name": { "family": "Buckley", "given": "Aya K." } }, { "id": "Henling-L-M", "name": { "family": "Henling", "given": "Lawrence M." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Bimetallic Coordination Insertion Polymerization of Unprotected Polar Monomers: Copolymerization of Amino Olefins and Ethylene by Dinickel Bisphenoxyiminato Catalysts", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2013 American Chemical Society. Received: January 15, 2013.\nPublication Date (Web): February 20, 2013. We thank Caltech and Dow Chemical for funding.\n\nPublished - ja4004816.pdf
Supplemental Material - ja4004816_si_001.pdf
Supplemental Material - ja4004816_si_002.cif
Supplemental Material - ja4004816_si_003.cif
", "abstract": "Dinickel bisphenoxyiminato complexes based on highly substituted p- and m-terphenyl backbones were synthesized, and the corresponding atropisomers were isolated. In the presence of a phosphine scavenger, Ni(COD)_2, the phosphine-ligated syn-dinickel complexes copolymerized \u03b1-olefins and ethylene in the presence of amines to afford 0.2\u20131.3% \u03b1-olefin incorporation and copolymerized amino olefins and ethylene with a similar range of incorporation (0.1\u20130.8%). The present rigid catalysts provide a bimetallic strategy for insertion polymerization of polar monomers without masking of the heteroatom group. The effects of the catalyst structure on the reactivity were studied by comparisons of the syn and anti atropisomers and the p- and m-terphenyl systems.", "date": "2013-03-13", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "135", "number": "10", "publisher": "American Chemical Society", "pagerange": "3784-3787", "id_number": "CaltechAUTHORS:20130415-072929452", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130415-072929452", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "Dow Chemical Company" } ] }, "doi": "10.1021/ja4004816", "primary_object": { "basename": "ja4004816_si_003.cif", "url": "https://authors.library.caltech.edu/records/emrvk-3ss86/files/ja4004816_si_003.cif" }, "related_objects": [ { "basename": "ja4004816.pdf", "url": "https://authors.library.caltech.edu/records/emrvk-3ss86/files/ja4004816.pdf" }, { "basename": "ja4004816_si_001.pdf", "url": "https://authors.library.caltech.edu/records/emrvk-3ss86/files/ja4004816_si_001.pdf" }, { "basename": "ja4004816_si_002.cif", "url": "https://authors.library.caltech.edu/records/emrvk-3ss86/files/ja4004816_si_002.cif" } ], "resource_type": "article", "pub_year": "2013", "author_list": "Radlauer, Madalyn R.; Buckley, Aya K.; et el." }, { "id": "https://authors.library.caltech.edu/records/m42p0-we209", "eprint_id": 37231, "eprint_status": "archive", "datestamp": "2023-08-19 14:25:36", "lastmod": "2023-10-23 17:16:22", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kanady-J-S", "name": { "family": "Kanady", "given": "Jacob S." } }, { "id": "Mendoza-Cortes-J-L", "name": { "family": "Mendoza-Cort\u00e9s", "given": "Jos\u00e9 L." } }, { "id": "Tsui-Emily-Y", "name": { "family": "Tsui", "given": "Emily Y." }, "orcid": "0000-0001-6419-3954" }, { "id": "Nielsen-R-J", "name": { "family": "Nielsen", "given": "Robert J." }, "orcid": "0000-0002-7962-0186" }, { "id": "Goddard-W-A-III", "name": { "family": "Goddard", "given": "William A., III" }, "orcid": "0000-0003-0097-5716" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Oxygen Atom Transfer and Oxidative Water Incorporation in Cuboidal Mn_(3)MO_n Complexes Based on Synthetic, Isotopic Labeling, and Computational Studies", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2012 American Chemical Society.\n\nReceived: October 12, 2012; Published: December 15, 2012.\n\nWe are grateful to California Institute of Technology, the Searle Scholars Program (T.A.), the Rose Hill Foundation (J.S.K.), the NSF GRFP (J.S.K. and E.Y.T.), and NSF CHE 1214158 (J.L.M.-C. R.A.N., W.A.G.) for funding. We thank M. W. Day and L. M. Henling for assistance with crystallography and M. Shahgholi for assistance with mass spectrometry. The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF CRIF:MU award to Caltech (CHE-0639094) and the computer cluster from NSF-CSEM (DMR-0520565). SQUID data were collected at the Molecular Materials Research Center of the Beckman Institute of the California Institute of Technology.\n\nPublished - ja310022p.pdf
Supplemental Material - ja310022p_si_001.pdf
Supplemental Material - ja310022p_si_002.cif
Supplemental Material - ja310022p_si_003.cif
", "abstract": "The oxygen-evolving complex (OEC) of photosystem II contains a Mn_(4)CaO_n catalytic site, in which reactivity of bridging oxidos is fundamental to OEC function. We synthesized structurally relevant cuboidal Mn_(3)MO_n complexes (M = Mn, Ca, Sc; n = 3,4) to enable mechanistic studies of reactivity and incorporation of \u03bc_(3)-oxido moieties. We found that Mn^(IV)_(3)CaO_4 and Mn^(IV)_(3)ScO_4 were unreactive toward trimethylphosphine (PMe_3). In contrast, our Mn^(III)_(2)Mn^(IV)_(2)O_4 cubane reacts with this phosphine within minutes to generate a novel Mn^(III)_(4)O_3 partial cubane plus Me_(3)PO. We used quantum mechanics to investigate the reaction paths for oxygen atom transfer to phosphine from Mn^(III)_(2)Mn^(IV)_(2)O_4 and Mn^(IV)_(3)CaO_4. We found that the most favorable reaction path leads to partial detachment of the CH_(3)COO^\u2013 ligand, which is energetically feasible only when Mn(III) is present. Experimentally, the lability of metal-bound acetates is greatest for Mn^(III)_(2)Mn^(IV)_(2)O_4. These results indicate that even with a strong oxygen atom acceptor, such as PMe_3, the oxygen atom transfer chemistry from Mn_(3)MO_4 cubanes is controlled by ligand lability, with the Mn^(IV)_(3)CaO_4 OEC model being unreactive. The oxidative oxide incorporation into the partial cubane, Mn^(III)_(4)O_3, was observed experimentally upon treatment with water, base, and oxidizing equivalents. ^(18)O-labeling experiments provided mechanistic insight into the position of incorporation in the partial cubane structure, consistent with mechanisms involving migration of oxide moieties within the cluster but not consistent with selective incorporation at the site available in the starting species. These results support recent proposals for the mechanism of the OEC, involving oxido migration between distinct positions within the cluster.", "date": "2013-01-23", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "135", "number": "3", "publisher": "American Chemical Society", "pagerange": "1073-1082", "id_number": "CaltechAUTHORS:20130301-100102927", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130301-100102927", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "Searle Scholars Program" }, { "agency": "Rose Hill Foundation" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "NSF", "grant_number": "CHE-1214158" } ] }, "doi": "10.1021/ja310022p", "primary_object": { "basename": "ja310022p.pdf", "url": "https://authors.library.caltech.edu/records/m42p0-we209/files/ja310022p.pdf" }, "related_objects": [ { "basename": "ja310022p_si_001.pdf", "url": "https://authors.library.caltech.edu/records/m42p0-we209/files/ja310022p_si_001.pdf" }, { "basename": "ja310022p_si_002.cif", "url": "https://authors.library.caltech.edu/records/m42p0-we209/files/ja310022p_si_002.cif" }, { "basename": "ja310022p_si_003.cif", "url": "https://authors.library.caltech.edu/records/m42p0-we209/files/ja310022p_si_003.cif" } ], "resource_type": "article", "pub_year": "2013", "author_list": "Kanady, Jacob S.; Mendoza-Cort\u00e9s, Jos\u00e9 L.; et el." }, { "id": "https://authors.library.caltech.edu/records/b1kbd-ar354", "eprint_id": 36800, "eprint_status": "archive", "datestamp": "2023-08-19 13:56:55", "lastmod": "2023-10-23 15:47:53", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lionetti-D", "name": { "family": "Lionetti", "given": "Davide" }, "orcid": "0000-0002-4937-886X" }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Metal-templated ligand architectures for trinuclear chemistry: tricopper complexes and their O_2 reactivity", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2013 Royal Society of Chemistry.\n\nReceived 16 Oct 2012, Accepted 25 November 2012; first published on the web 26 November 2012.\n\nWe thank Lawrence M. Henling for crystallographic assistance.\nWe are grateful to Caltech and the ACS Petroleum Research\nFund for funding. The Bruker KAPPA APEXII X-ray diffractometer\nwas purchased via an NSF CRIF:MU award to Caltech, CHE-\n0639094. The 400 MHz NMR spectrometer was purchased via an\nNIH award, RR027690.\n\nSupplemental Material - c2sc21758a.pdf
", "abstract": "A trinucleating framework was assembled by templation of a heptadentate ligand around yttrium and lanthanides. The generated complexes orient three sets of two or three N-donors each for binding additional metal centers. Addition of three equivalents of copper(I) leads to the formation of tricopper(I) species. Reactions with dioxygen at low temperatures generate species whose spectroscopic features are consistent with a \u03bc_3,\u03bc_3-dioxo-tricopper complex. Reactivity studies were performed with a variety of substrates. The dioxo-tricopper species deprotonates weak acids, undergoes oxygen atom transfer with triphenylphosphine to yield triphenylphosphine oxide, and performs hydrogen atom abstraction from tetramethylpiperidine-N-hydroxide (TEMPO-H). Thiophenols reduce the oxygenated species to a Cu_3^I complex and liberate two equivalents of disulfide, consistent with a four-electron four-proton process.", "date": "2013", "date_type": "published", "publication": "Chemical Science", "volume": "4", "number": "2", "publisher": "Royal Society of Chemistry", "pagerange": "785-790", "id_number": "CaltechAUTHORS:20130206-145708635", "issn": "2041-6520", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130206-145708635", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "American Chemical Society Petroleum Research Fund" }, { "agency": "NSF", "grant_number": "CHE-0639094" }, { "agency": "NIH", "grant_number": "RR027690" } ] }, "doi": "10.1039/c2sc21758a", "pmcid": "PMC3607385", "primary_object": { "basename": "c2sc21758a.pdf", "url": "https://authors.library.caltech.edu/records/b1kbd-ar354/files/c2sc21758a.pdf" }, "resource_type": "article", "pub_year": "2013", "author_list": "Lionetti, Davide; Day, Michael W.; et el." }, { "id": "https://authors.library.caltech.edu/records/1azqr-ez397", "eprint_id": 32461, "eprint_status": "archive", "datestamp": "2023-08-19 11:19:02", "lastmod": "2023-10-18 14:26:20", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Mindiola-D-J", "name": { "family": "Mindiola", "given": "Daniel J." } }, { "id": "Arnold-J", "name": { "family": "Arnold", "given": "John" }, "orcid": "0000-0001-9671-227X" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Love-J-A", "name": { "family": "Love", "given": "Jennifer" }, "orcid": "0000-0003-2373-1036" }, { "id": "Dinca-M", "name": { "family": "Dinca", "given": "Mircea" }, "orcid": "0000-0002-1262-1264" } ] }, "title": "New talent: Americas", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2012 Royal Society of Chemistry. \n\nFirst published on the web 06 Jun 2012.\n\nPublished - Mindiola2012p18821Dalton_Transactions.pdf
", "abstract": "N/A", "date": "2012-06-06", "date_type": "published", "publication": "Dalton Transactions", "volume": "41", "number": "26", "publisher": "Royal Society of Chemistry", "pagerange": "7781-7781", "id_number": "CaltechAUTHORS:20120716-100214997", "issn": "1477-9226", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120716-100214997", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1039/c2dt90087d", "primary_object": { "basename": "Mindiola2012p18821Dalton_Transactions.pdf", "url": "https://authors.library.caltech.edu/records/1azqr-ez397/files/Mindiola2012p18821Dalton_Transactions.pdf" }, "resource_type": "article", "pub_year": "2012", "author_list": "Mindiola, Daniel J.; Arnold, John; et el." }, { "id": "https://authors.library.caltech.edu/records/9cpv9-2je58", "eprint_id": 32441, "eprint_status": "archive", "datestamp": "2023-08-19 10:58:02", "lastmod": "2023-10-17 23:49:21", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kelley-P", "name": { "family": "Kelley", "given": "Paul" } }, { "id": "Radlauer-M-R", "name": { "family": "Radlauer", "given": "Madalyn R." }, "orcid": "0000-0002-3226-5340" }, { "id": "Yanez-A-J", "name": { "family": "Yanez", "given": "Abraham J." } }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Metallomacrocycles as ligands: synthesis and characterisation of aluminium-bridged bisglyoximato complexes of palladium and iron", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2012 Royal Society of Chemistry.\n\nReceived 9th February 2012; Accepted 16th April 2012.\nFirst published on the web 14 May 2012.\nWe thank Lawrence M. Henling for collection of XRD data and\npreliminary structure analysis and Dr. David E. Herbert for\ncrystal structures of 3b and 8tBu. We are grateful to Caltech, Dow Chemical and the Caltech MURF program (AJY) for\nfunding. The Bruker KAPPA APEXII X-ray diffractometer was\npurchased via an NSF CRIF:MU award to Caltech,\nCHE-0639094.\n\nPublished - Kelley2012p18820Dalton_Transactions.pdf
Supplemental Material - c2dt30285c.pdf
Supplemental Material - c2dt30285c.txt
", "abstract": "Dialuminiummacrocycles based on bisglyoximato moieties were prepared and their coordination chemistry with Fe^II and Pd^II was investigated. The bridging aluminium centers were supported by several types of tetradentate diphenoxide diamine ligands. The nature of the ancillary ligands bound to aluminium was found to affect the overall geometry and symmetry of the metallomacrocycles. Enantiopure, chiral diphenoxide ligands based on the (R,R)-trans-1,2-diaminocyclohexane backbone afforded cleanly one metallomacrocycle isomer. The size and electronic properties of remote substituents on aluminium-bound ligands affected the binding mode and electronic properties of the central iron. A structurally characterized iron complex shows trigonal prismatic coordination mode, with phenoxide bridges between iron and aluminium. Increasing the size of the phenoxide substituents led to square bipyramidal coordination at iron. Employing p-NO_2- instead of p-tBu-substituted phenoxide as supporting ligands for aluminium caused a 0.27 V positive shift of the Fe^(III)/Fe^(II) reduction potential. These results indicate that the present synthetic approach can be applied to a variety of metallomacrocycles based on bisglyoximato motifs to affect the chemistry at the central metal.", "date": "2012-05-14", "date_type": "published", "publication": "Dalton Transactions", "volume": "41", "number": "26", "publisher": "Royal Society of Chemistry", "pagerange": "8086-8092", "id_number": "CaltechAUTHORS:20120713-152737041", "issn": "1477-9226", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120713-152737041", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "Dow Chemical" }, { "agency": "Caltech Minorities Undergraduate Research Fellowship (MURF)" }, { "agency": "NSF", "grant_number": "CHE-0639094" } ] }, "doi": "10.1039/c2dt30285c", "primary_object": { "basename": "Kelley2012p18820Dalton_Transactions.pdf", "url": "https://authors.library.caltech.edu/records/9cpv9-2je58/files/Kelley2012p18820Dalton_Transactions.pdf" }, "related_objects": [ { "basename": "c2dt30285c.pdf", "url": "https://authors.library.caltech.edu/records/9cpv9-2je58/files/c2dt30285c.pdf" }, { "basename": "c2dt30285c.txt", "url": "https://authors.library.caltech.edu/records/9cpv9-2je58/files/c2dt30285c.txt" } ], "resource_type": "article", "pub_year": "2012", "author_list": "Kelley, Paul; Radlauer, Madalyn R.; et el." }, { "id": "https://authors.library.caltech.edu/records/bknpq-2b209", "eprint_id": 31321, "eprint_status": "archive", "datestamp": "2023-08-19 10:24:26", "lastmod": "2023-10-17 16:03:49", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kelley-P", "name": { "family": "Kelley", "given": "Paul" } }, { "id": "Lin-Sibo", "name": { "family": "Lin", "given": "Sibo" }, "orcid": "0000-0001-5922-6694" }, { "id": "Edouard-G", "name": { "family": "Edouard", "given": "Guy" } }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Nickel-Mediated Hydrogenolysis of C\u2013O Bonds of Aryl Ethers: What Is the Source of the Hydrogen?", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2012 American Chemical Society. \n\nReceived: January 12, 2012. Published: March 6, 2012. \n\nWe thank Lawrence M. Henling for crystallographic assistance. We are grateful to Caltech, BP, and NSF GRFP (S.L.) for funding. The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF CRIF:MU award to Caltech, CHE-0639094. The 400 MHz NMR spectrometer was purchased via an NIH award, RR027690.\n\nAccepted Version - nihms363520.pdf
Supplemental Material - ja300326t_si_001.pdf
Supplemental Material - ja300326t_si_002.cif
Supplemental Material - ja300326t_si_003.cif
Supplemental Material - ja300326t_si_004.cif
", "abstract": "Mechanistic studies of the hydrogenolysis of aryl ethers by nickel were undertaken with (diphosphine)aryl methyl ethers. A Ni(0) complex containing Ni\u2013arene interactions adjacent to the aryl\u2013O bond was isolated. Heating led to aryl\u2013O bond activation and generation of a nickel aryl methoxide complex. Formal \u03b2-H elimination from this species produced a nickel aryl hydride which can undergo reductive elimination in the presence of formaldehyde to generate a carbon monoxide adduct of Ni(0). The reported complexes map out a plausible mechanism of aryl ether hydrogenolysis catalyzed by nickel. Investigations of a previously reported catalytic system using isotopically labeled substrates are consistent with the mechanism proposed in the stoichiometric system, involving \u03b2-H elimination from a nickel alkoxide rather than cleavage of the Ni\u2013O bond by H_2.", "date": "2012-03-28", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "134", "number": "12", "publisher": "American Chemical Society", "pagerange": "5480-5483", "id_number": "CaltechAUTHORS:20120507-081119603", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120507-081119603", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "BP" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "NSF", "grant_number": "CHE-0639094" }, { "agency": "NIH", "grant_number": "RR027690" } ] }, "doi": "10.1021/ja300326t", "pmcid": "PMC3340012", "primary_object": { "basename": "nihms363520.pdf", "url": "https://authors.library.caltech.edu/records/bknpq-2b209/files/nihms363520.pdf" }, "related_objects": [ { "basename": "ja300326t_si_001.pdf", "url": "https://authors.library.caltech.edu/records/bknpq-2b209/files/ja300326t_si_001.pdf" }, { "basename": "ja300326t_si_002.cif", "url": "https://authors.library.caltech.edu/records/bknpq-2b209/files/ja300326t_si_002.cif" }, { "basename": "ja300326t_si_003.cif", "url": "https://authors.library.caltech.edu/records/bknpq-2b209/files/ja300326t_si_003.cif" }, { "basename": "ja300326t_si_004.cif", "url": "https://authors.library.caltech.edu/records/bknpq-2b209/files/ja300326t_si_004.cif" } ], "resource_type": "article", "pub_year": "2012", "author_list": "Kelley, Paul; Lin, Sibo; et el." }, { "id": "https://authors.library.caltech.edu/records/qvpfm-wjn74", "eprint_id": 30244, "eprint_status": "archive", "datestamp": "2023-08-19 10:22:50", "lastmod": "2023-10-17 15:35:13", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Radlauer-M-R", "name": { "family": "Radlauer", "given": "Madalyn R." }, "orcid": "0000-0002-3226-5340" }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Dinickel Bisphenoxyiminato Complexes for the Polymerization of\n Ethylene and \u03b1-Olefins", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2012 American Chemical Society. \n\nReceived: November 22, 2011. Publication Date (Web): March 8, 2012. \n\nWe thank Lawrence M. Henling (Caltech) for assistance with collection of crystallographic data and Jerzy Klosin (Dow Chemical) for the collection of GPC data. We are grateful to Dow Chemical and Caltech for funding. The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF CRIF:MU Award to Caltech (Grant No. CHE-0639094). The 400 MHz NMR spectrometer was purchased via an NIH award (No. RR027690).\n\nAccepted Version - nihms362745.pdf
Supplemental Material - om2011694_si_001.pdf
Supplemental Material - om2011694_si_002.cif
Supplemental Material - om2011694_si_003.cif
", "abstract": "Dinuclear nickel phenoxyiminato olefin polymerization catalysts based on rigid p-terphenyl frameworks are reported. Permethylation of the central arene of the terphenyl unit and oxygen substitution of the peripheral rings ortho to the aryl\u2013aryl linkages blocks rotation around these linkages, allowing atropisomers of the ligand to be isolated. The corresponding syn and anti dinickel complexes (25-s and 25-a) were synthesized and characterized by single-crystal X-ray diffraction. These frameworks limit the relative movement of the metal centers, restricting the metal\u2013metal distance. Kinetics studies of isomerization of a ligand precursor (7-a) allowed the calculation of the activation parameters for the isomerization process (\u0394H^\u2021 = 28.0 \u00b1 0.4 kcal \u00d7 mol^(\u20131) and \u0394S^\u2021 = \u221212.3 \u00b1 0.4 cal mol^(\u20131) K^(\u20131)). The reported nickel complexes are active for ethylene polymerization (TOF up to 3700 (mol C_2H_4) (mol Ni)^(\u22121) h^(\u20131)) and ethylene/\u03b1-olefin copolymerization. Only methyl branches are observed in the polymerization of ethylene, while \u03b1-olefins are incorporated without apparent chain walking. These catalysts are active in the presence of polar additives and in neat tetrahydrofuran. The syn and anti isomers differ in polymerization activity, polymer branching, and polymer molecular weight. For comparison, a series of mononuclear nickel complexes (26, 27-s, 27-a, 28, 30) was prepared and studied. The effects of structure and catalyst nuclearity on reactivity are discussed.", "date": "2012-03-26", "date_type": "published", "publication": "Organometallics", "volume": "31", "number": "6", "publisher": "American Chemical Society", "pagerange": "2231-2243", "id_number": "CaltechAUTHORS:20120420-144952369", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120420-144952369", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" }, { "agency": "Caltech" }, { "agency": "NSF", "grant_number": "CHE-0639094" }, { "agency": "NIH", "grant_number": "RR027690" } ] }, "doi": "10.1021/om2011694", "pmcid": "PMC3375993", "primary_object": { "basename": "nihms362745.pdf", "url": "https://authors.library.caltech.edu/records/qvpfm-wjn74/files/nihms362745.pdf" }, "related_objects": [ { "basename": "om2011694_si_001.pdf", "url": "https://authors.library.caltech.edu/records/qvpfm-wjn74/files/om2011694_si_001.pdf" }, { "basename": "om2011694_si_002.cif", "url": "https://authors.library.caltech.edu/records/qvpfm-wjn74/files/om2011694_si_002.cif" }, { "basename": "om2011694_si_003.cif", "url": "https://authors.library.caltech.edu/records/qvpfm-wjn74/files/om2011694_si_003.cif" } ], "resource_type": "article", "pub_year": "2012", "author_list": "Radlauer, Madalyn R.; Day, Michael W.; et el." }, { "id": "https://authors.library.caltech.edu/records/peacn-at859", "eprint_id": 30165, "eprint_status": "archive", "datestamp": "2023-08-19 10:15:55", "lastmod": "2023-10-17 15:31:05", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Tonks-I-A", "name": { "family": "Tonks", "given": "Ian A." } }, { "id": "Tofan-D", "name": { "family": "Tofan", "given": "Daniel" } }, { "id": "Weintrob-E-C", "name": { "family": "Weintrob", "given": "Edward C." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Bercaw-J-E", "name": { "family": "Bercaw", "given": "John E." } } ] }, "title": "Zirconium and Titanium Propylene Polymerization Precatalysts Supported by a Fluxional C_2-Symmetric Bis(anilide)pyridine Ligand", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2012 American Chemical Society. Received: December 20, 2011. Publication Date (Web): February 16, 2012. We thank Lawrence Henling and Dr. Michael Day for\nassistance with the X-ray studies. The Bruker KAPPA APEXII\nX-ray diffractometer was purchased via an NSF CRIF:MU\naward to the California Institute of Technology, CHE-0639094.\nDFT calculations were carried out using the Molecular\nGraphics and Computation Facility, College of Chemistry,\nUniversity of California, Berkeley, CA, with equipment support\nfrom NSF Grant No. CHE-0233882. We acknowledge Dr. Jo\nAnn Canich (Exxon) for the GPC data and for experimental\ninsight. This work has been supported by the USDOE Office of\nBasic Energy Sciences (Grant No. DE-FG03-85ER13431) and\nby the KAUST Center-In-Development at King Fahd\nUniversity of Petroleum and Minerals (Dhahran, Saudi Arabia).\n\nSupplemental Material - om201262h_si_001.pdf
Supplemental Material - om201262h_si_002.cif
", "abstract": "Titanium and zirconium complexes supported by a bis(anilide)pyridine ligand (NNN = pyridine-2,6-bis(N-mesitylanilide)) have been synthesized and crystallographically characterized. C_2-symmetric bis(dimethylamide) complexes were generated from aminolysis of M(NMe_2)_4 with the neutral, diprotonated NNN ligand or by salt metathesis of the dipotassium salt of NNN with M(NMe_2)_2Cl_2. In contrast to the case for previously reported pyridine bis(phenoxide) complexes, the ligand geometry of these complexes appears to be dictated by chelate ring strain rather than metal\u2013ligand \u03c0 bonding. The crystal structures of the five-coordinate dihalide complexes (NNN)MCl_2 (M = Ti, Zr) display a C_1-symmetric geometry with a stabilizing ipso interaction between the metal and the anilido ligand. Coordination of THF to (NNN)ZrCl_2 generates a six-coordinate C_2-symmetric complex. Facile antipode interconversion of the C_2 complexes, possibly via flat C_(2v) intermediates, has been investigated by variable-temperature ^1H NMR spectroscopy for (NNN)MX_2(THF)_n (M = Ti, Zr; X = NMe_2, Cl) and (NNN)Zr(CH_2Ph)_2. These complexes were tested as propylene polymerization precatalysts, with most complexes giving low to moderate activities (10^2\u201310^4 g/(mol h)) for the formation of stereoirregular polypropylene.", "date": "2012-03-12", "date_type": "published", "publication": "Organometallics", "volume": "31", "number": "5", "publisher": "American Chemical Society", "pagerange": "1965-1974", "id_number": "CaltechAUTHORS:20120418-111611466", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120418-111611466", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-0639094" }, { "agency": "NSF", "grant_number": "CHE-0233882" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-FG03-85ER13431" }, { "agency": "King Abdullah University of Science and Technology (KAUST)" } ] }, "doi": "10.1021/om201262h", "primary_object": { "basename": "om201262h_si_001.pdf", "url": "https://authors.library.caltech.edu/records/peacn-at859/files/om201262h_si_001.pdf" }, "related_objects": [ { "basename": "om201262h_si_002.cif", "url": "https://authors.library.caltech.edu/records/peacn-at859/files/om201262h_si_002.cif" } ], "resource_type": "article", "pub_year": "2012", "author_list": "Tonks, Ian A.; Tofan, Daniel; et el." }, { "id": "https://authors.library.caltech.edu/records/6ajar-jzh19", "eprint_id": 29958, "eprint_status": "archive", "datestamp": "2023-08-19 09:41:06", "lastmod": "2023-10-24 22:37:05", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Radlauer-M-R", "name": { "family": "Radlauer", "given": "Madalyn R." }, "orcid": "0000-0002-3226-5340" }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Bimetallic Effects on Ethylene Polymerization in the Presence of Amines: Inhibition of the Deactivation by Lewis Bases", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2012 American Chemical Society.\n\nPublished In Issue January 25, 2012; Article ASAP January 12, 2012; Just Accepted Manuscript January 06, 2012; Received: November 22, 2011.\n\nWe thank Lawrence M. Henling for crystallographic assistance. We are grateful to Caltech and Dow Chemical for funding. The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF CRIF:MU award to Caltech (CHE-0639094). The 400 MHz NMR spectrometer was purchased via NIH Award RR027690.\n\nAccepted Version - nihms349781.pdf
Supplemental Material - ja210990t_si_001.pdf
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", "abstract": "Dinickel complexes supported by terphenyl ligands appended with phenoxy and imine donors were synthesized. Full substitution of the central arene blocks rotation around the aryl\u2013aryl bond and allows for the isolation of atropisomers. The reported complexes perform ethylene polymerization in the presence of amines. The inhibiting effect of polar additives is up to 250 times lower for the syn isomer than the anti isomer. Comparisons with mononuclear systems indicate that the proximity of the metal centers leads to the observed inhibitory effect on the deactivation of the catalysts.", "date": "2012-01-25", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "134", "number": "3", "publisher": "American Chemical Society", "pagerange": "1478-1481", "id_number": "CaltechAUTHORS:20120403-131656142", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120403-131656142", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "Dow Chemical" }, { "agency": "NSF", "grant_number": "CHE-0639094" }, { "agency": "NIH", "grant_number": "RR027690" } ] }, "doi": "10.1021/ja210990t", "pmcid": "PMC3307529", "primary_object": { "basename": "ja210990t_si_001.pdf", "url": "https://authors.library.caltech.edu/records/6ajar-jzh19/files/ja210990t_si_001.pdf" }, "related_objects": [ { "basename": "ja210990t_si_002.cif", "url": "https://authors.library.caltech.edu/records/6ajar-jzh19/files/ja210990t_si_002.cif" }, { "basename": "ja210990t_si_003.cif", "url": "https://authors.library.caltech.edu/records/6ajar-jzh19/files/ja210990t_si_003.cif" }, { "basename": "ja210990t_si_004.cif", "url": "https://authors.library.caltech.edu/records/6ajar-jzh19/files/ja210990t_si_004.cif" }, { "basename": "nihms349781.pdf", "url": "https://authors.library.caltech.edu/records/6ajar-jzh19/files/nihms349781.pdf" } ], "resource_type": "article", "pub_year": "2012", "author_list": "Radlauer, Madalyn R.; Day, Michael W.; et el." }, { "id": "https://authors.library.caltech.edu/records/h2hmj-z6621", "eprint_id": 29957, "eprint_status": "archive", "datestamp": "2023-08-19 09:34:28", "lastmod": "2023-10-24 22:36:59", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Whited-C-A", "name": { "family": "Whited", "given": "Charlotte A." } }, { "id": "Warren-J-J", "name": { "family": "Warren", "given": "Jeffrey J." }, "orcid": "0000-0002-1747-3029" }, { "id": "Lavoie-K-D", "name": { "family": "Lavoie", "given": "Katherine D." } }, { "id": "Weinert-E-E", "name": { "family": "Weinert", "given": "Emily E." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Winkler-J-R", "name": { "family": "Winkler", "given": "Jay R." }, "orcid": "0000-0002-4453-9716" }, { "id": "Gray-H-B", "name": { "family": "Gray", "given": "Harry B." }, "orcid": "0000-0002-7937-7876" } ] }, "title": "Gating NO Release from Nitric Oxide Synthase", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2011 American Chemical Society. Received: July 29, 2011. Publication Date (Web): December 7, 2011. C.A.W. thanks Michael Winter for valuable discussions and Dr. Josh Woodward for a spectrum of ferric-NO NOS. Supported by an NSF graduate fellowship (C.A.W.), the NIH (DK019038 to H.B.G. and J.R.W.; GM068461 to J.R.W.; GM095037 postdoctoral fellowship to J.J.W.), and the Arnold and Mabel Beckman Foundation.\n\nAccepted Version - nihms343029.pdf
Supplemental Material - ja2069533_si_001.pdf
", "abstract": "We have investigated the kinetics of NO escape from Geobacillus stearothermophilus nitric oxide synthase (gsNOS). Previous work indicated that NO release was gated at position 223 in mammalian enzymes; our kinetics experiments include mutants at that position along with measurements on the wild type enzyme. Employing stopped-flow UV\u2013vis methods, reactions were triggered by mixing a reduced enzyme/N-hydroxy-l-arginine complex with an aerated buffer solution. NO release kinetics were obtained for wt NOS and three mutants (H134S, I223V, H134S/I223V). We have confirmed that wt gsNOS has the lowest NO release rate of known NOS enzymes, whether bacterial or mammalian. We also have found that steric clashes at positions 223 and 134 hinder NO escape, as judged by enhanced rates in the single mutants. The empirical rate of NO release from the gsNOS double mutant (H134/I223V) is nearly as rapid as that of the fastest mammalian enzymes, demonstrating that both positions 223 and 134 function as gates for escape of the product diatomic molecule.", "date": "2012-01-11", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "134", "number": "1", "publisher": "American Chemical Society", "pagerange": "27-30", "id_number": "CaltechAUTHORS:20120403-112410644", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120403-112410644", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF Graduate Research Fellowship" }, { "agency": "NIH", "grant_number": "DK019038" }, { "agency": "NIH", "grant_number": "GM068461" }, { "agency": "NIH", "grant_number": "GM095037" }, { "agency": "Arnold and Mabel Beckman Foundation" } ] }, "doi": "10.1021/ja2069533", "pmcid": "PMC3257399", "primary_object": { "basename": "ja2069533_si_001.pdf", "url": "https://authors.library.caltech.edu/records/h2hmj-z6621/files/ja2069533_si_001.pdf" }, "related_objects": [ { "basename": "nihms343029.pdf", "url": "https://authors.library.caltech.edu/records/h2hmj-z6621/files/nihms343029.pdf" } ], "resource_type": "article", "pub_year": "2012", "author_list": "Whited, Charlotte A.; Warren, Jeffrey J.; et el." }, { "id": "https://authors.library.caltech.edu/records/9d9j0-ep666", "eprint_id": 25285, "eprint_status": "archive", "datestamp": "2023-08-22 03:25:22", "lastmod": "2023-10-24 15:45:45", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Chao-Steven-T", "name": { "family": "Chao", "given": "Steven T." } }, { "id": "Lara-N-C", "name": { "family": "Lara", "given": "Nadia C." } }, { "id": "Lin-Sibo", "name": { "family": "Lin", "given": "Sibo" }, "orcid": "0000-0001-5922-6694" }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Reversible Halide-Modulated Nickel\u2013Nickel Bond Cleavage: Metal\u2013Metal Bonds as Design Elements for Molecular Devices", "ispublished": "pub", "full_text_status": "public", "keywords": "chlorine; nickel; metal\u2013arene interactions; metal\u2013metal bonds; P ligands", "note": "\u00a9 2011 Wiley-VCH Verlag. \n\nIssue published online: 5 Aug 2011. Article first published online: 27 Jun 2011. Manuscript Received: 22 Apr 2011. \n\nWe thank Lawrence M. Henling for assistance with collection of crystallographic data. We are grateful to NSF GRFP (S.L.), Caltech, SURF office (N.C.L.), and bp for funding. The Bruker KAPPA APEXII X-ray diffractometer was purchased through an NSF CRIF:MU\nAward to Caltech (CHE-0639094). The 400 MHz NMR spectrometer\nwas purchased through an NIH award, RR027690.\n\nAccepted Version - nihms416657.pdf
Supplemental Material - anie_201102797_sm_miscellaneous_information.pdf
", "abstract": "The dinickel chloride affair: In dinuclear nickel(I) complexes supported by a tris(phosphinoaryl)benzene and stabilized by metal\u2013arene interactions, chloride addition causes reversible Ni-Ni bond cleavage that induces 180\u00b0 rotation around an aryl\u2013aryl bond (see scheme). A dinickel\u2013chloride moiety was found to rotate around the bridging arene by a mechanism involving breaking and forming Ni-P bonds.", "date": "2011-08-08", "date_type": "published", "publication": "Angewandte Chemie International Edition", "volume": "50", "number": "33", "publisher": "Wiley", "pagerange": "7529-7532", "id_number": "CaltechAUTHORS:20110912-073149077", "issn": "1433-7851", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110912-073149077", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF Graduate Research Fellowship" }, { "agency": "Caltech Summer Undergraduate Research Fellowship (SURF)" }, { "agency": "BP" }, { "agency": "NSF", "grant_number": "CHE-0639094" }, { "agency": "NIH", "grant_number": "RR027690" } ] }, "doi": "10.1002/anie.201102797", "pmcid": "PMC3805114", "primary_object": { "basename": "nihms416657.pdf", "url": "https://authors.library.caltech.edu/records/9d9j0-ep666/files/nihms416657.pdf" }, "related_objects": [ { "basename": "anie_201102797_sm_miscellaneous_information.pdf", "url": "https://authors.library.caltech.edu/records/9d9j0-ep666/files/anie_201102797_sm_miscellaneous_information.pdf" } ], "resource_type": "article", "pub_year": "2011", "author_list": "Chao, Steven T.; Lara, Nadia C.; et el." }, { "id": "https://authors.library.caltech.edu/records/47zpe-45604", "eprint_id": 24980, "eprint_status": "archive", "datestamp": "2023-08-19 07:41:26", "lastmod": "2023-10-24 15:30:42", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kanady-J-S", "name": { "family": "Kanady", "given": "Jacob S." } }, { "id": "Tsui-Emily-Y", "name": { "family": "Tsui", "given": "Emily Y." }, "orcid": "0000-0001-6419-3954" }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "A Synthetic Model of the Mn_3Ca Subsite of the Oxygen-Evolving Complex in Photosystem II", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2011 American Association for the Advancement of Science.\n\nReceived for publication 24 March 2011; accepted for publication 5 July 2011.\n\nWe thank California Institute of Technology, the Searle Scholars Program (T.A.), the Rose Hill Foundation (J.S.K.), and the NSF Graduate Research Fellowship Program (E.Y.T.) for funding. We also thank L. M. Henling for assistance with crystallography. The Bruker KAPPA APEXII x-ray diffractometer was purchased via an NSF Chemistry Research Instrumentation and Facilities: Departmental Multi-User Instrumentation award to Caltech (CHE-0639094). Crystallographic data have been deposited at the Cambridge Crystallographic Database Centre, and copies can be obtained on request, free of charge, by quoting the publication citation and the deposition numbers 817379 (3), 817683 (4), and 817924 (5).\n\nSupplemental Material - 1206036-Kanady-SOM.pdf
", "abstract": "Within photosynthetic organisms, the oxygen-evolving complex (OEC) of photosystem II generates dioxygen from water using a catalytic Mn_(4)CaOn cluster (n varies with the mechanism and nature of the intermediate). We report here the rational synthesis of a [Mn_(3)CaO_4]^(6+) cubane that structurally models the trimanganese-calcium\u2013cubane subsite of the OEC. Structural and electrochemical comparison between Mn_(3)CaO_4 and a related Mn_(4)O_4 cubane alongside characterization of an intermediate calcium-manganese multinuclear complex reveals potential roles of calcium in facilitating high oxidation states at manganese and in the assembly of the biological cluster.", "date": "2011-08-05", "date_type": "published", "publication": "Science", "volume": "333", "number": "6043", "publisher": "American Association for the Advancement of Science", "pagerange": "733-736", "id_number": "CaltechAUTHORS:20110822-132939719", "issn": "0036-8075", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110822-132939719", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "Searle Scholars Program" }, { "agency": "Rose Hill Foundation" }, { "agency": "NSF Graduate Research Fellowship" } ] }, "doi": "10.1126/science.1206036", "primary_object": { "basename": "1206036-Kanady-SOM.pdf", "url": "https://authors.library.caltech.edu/records/47zpe-45604/files/1206036-Kanady-SOM.pdf" }, "resource_type": "article", "pub_year": "2011", "author_list": "Kanady, Jacob S.; Tsui, Emily Y.; et el." }, { "id": "https://authors.library.caltech.edu/records/xcp0b-zp928", "eprint_id": 23569, "eprint_status": "archive", "datestamp": "2023-08-22 02:23:51", "lastmod": "2023-10-23 19:45:58", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Selective ethylene oligomerization: Recent advances in chromium catalysis and mechanistic investigations", "ispublished": "pub", "full_text_status": "restricted", "keywords": "Ethylene trimerization; Tetramerization; Selective oligomerization; Catalytic olefin oligomerization; Alpha-olefins; Chromium catalysis; Isotopic labeling; 1-Hexene; 1-Octene", "note": "\u00a9 2010 Elsevier B.V. \n\nAvailable online 2 December 2010. \n\nI am grateful to BP Chemicals (then Innovene) and the USDOE\nOffice of Basic Energy Sciences (Grant No. DE-FG03-85ER13431) for financial support of the selective ethylene trimerization reaction in the Bercaw group. I am indebted to John Bercaw and Jay Labinger for their mentorship during my doctoral studies and beyond, and my colleagues working on related chemistry in the Bercaw group, Susan Schofer and Paul Elowe, for stimulating discussions. Note: After the submission of this manuscript a review that covers\nprocesses for the production of 1-octene, including the selective tetramerization of ethylene, appeared in press [127].", "abstract": "Selective production of linear \u03b1-olefins is of significant commercial interest. Recently discovered catalytic systems based on titanium, tantalum, and chromium show remarkable selectivity and productivity for the oligomerization of ethylene to 1-hexene or 1-octene. Chromium-based catalysts are the most selective and active and show the highest structural diversity. This paper discusses the most recent advances in chromium chemistry related to selective olefin oligomerization. Aspects regarding ligand design, catalyst generation, selectivity for different products, and reaction mechanism are presented. Isotopic labeling protocols designed to distinguish between various mechanisms of catalysis are reviewed.", "date": "2011-04", "date_type": "published", "publication": "Coordination Chemistry Reviews", "volume": "255", "number": "7-8", "publisher": "Elsevier", "pagerange": "861-880", "id_number": "CaltechAUTHORS:20110506-100717427", "issn": "0010-8545", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110506-100717427", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "BP Chemicals" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-FG03-85ER13431" } ] }, "doi": "10.1016/j.ccr.2010.11.035", "resource_type": "article", "pub_year": "2011", "author_list": "Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/vh9tx-2sv78", "eprint_id": 23557, "eprint_status": "archive", "datestamp": "2023-08-19 05:56:07", "lastmod": "2023-10-23 19:45:11", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lin-Sibo", "name": { "family": "Lin", "given": "Sibo" }, "orcid": "0000-0001-5922-6694" }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Nickel Hydrides Supported by a Non-Innocent Diphosphine Arene Pincer: Mechanistic Studies of Nickel\u2212Arene H-Migration and Partial Arene Hydrogenation", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2011 American Chemical Society. \n\nReceived: January 14, 2011. Published: February 23, 2011. \n\nWe thank Lawrence M. Henling for crystallographic assistance. We are grateful to Caltech, BP, and NSF GRFP (S.L.) for funding. The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF CRIF:MU award to Caltech, CHE-063-9094. The 400 MHz NMR spectrometer was purchased via an NIH award, RR027690.\n\nAccepted Version - nihms275958.pdf
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Supplemental Material - ja200368y_si_005.cif
", "abstract": "Nickel hydrides supported by a terphenyl diphosphine were synthesized and found to undergo nickel-to-arene H-transfers. Some of the resulting complexes also undergo the reverse (C-to-Ni) H-migration, indicating the potential for storing H-equivalents in this type of pincer ligand. NMR spectroscopy, single crystal X-ray diffraction, and isotopic labeling studies investigating the mechanism of these processes are discussed.", "date": "2011-03-23", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "133", "number": "11", "publisher": "American Chemical Society", "pagerange": "3828-3831", "id_number": "CaltechAUTHORS:20110505-085619012", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110505-085619012", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "BP" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "NSF", "grant_number": "CHE-0639094" }, { "agency": "NIH", "grant_number": "RR027690" } ] }, "doi": "10.1021/ja200368y", "pmcid": "PMC3060299", "primary_object": { "basename": "ja200368y_si_001.pdf", "url": "https://authors.library.caltech.edu/records/vh9tx-2sv78/files/ja200368y_si_001.pdf" }, "related_objects": [ { "basename": "ja200368y_si_002.cif", "url": "https://authors.library.caltech.edu/records/vh9tx-2sv78/files/ja200368y_si_002.cif" }, { "basename": "ja200368y_si_003.cif", "url": "https://authors.library.caltech.edu/records/vh9tx-2sv78/files/ja200368y_si_003.cif" }, { "basename": "ja200368y_si_004.cif", "url": "https://authors.library.caltech.edu/records/vh9tx-2sv78/files/ja200368y_si_004.cif" }, { "basename": "ja200368y_si_005.cif", "url": "https://authors.library.caltech.edu/records/vh9tx-2sv78/files/ja200368y_si_005.cif" }, { "basename": "nihms275958.pdf", "url": "https://authors.library.caltech.edu/records/vh9tx-2sv78/files/nihms275958.pdf" } ], "resource_type": "article", "pub_year": "2011", "author_list": "Lin, Sibo; Day, Michael W.; et el." }, { "id": "https://authors.library.caltech.edu/records/4wbab-y0741", "eprint_id": 22921, "eprint_status": "archive", "datestamp": "2023-08-19 05:33:12", "lastmod": "2023-10-23 17:20:56", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Tsui-Emily-Y", "name": { "family": "Tsui", "given": "Emily Y." }, "orcid": "0000-0001-6419-3954" }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Trinucleating Copper: Synthesis and Magnetostructural\n Characterization of Complexes Supported by a Hexapyridyl\n 1,3,5-Triarylbenzene Ligand", "ispublished": "pub", "full_text_status": "public", "keywords": "copper complexes, dioxygen, magnetic properties, multinucleating ligands, trinuclear clusters", "note": "\u00a9 2011 Wiley. \n\nReceived: August 21, 2010. Revised: October 24, 2010. Published online: January 11, 2011. \n\nWe thank Lawrence\u2005M. Henling for crystallographic assistance, David Vandervelde for help with NMR experiments, and Harry Gray, Jay Winkler and Liviu Mirica for stimulating discussions. We are grateful to Caltech and NSF GRFP (E.Y.T.) for funding. The Bruker KAPPA APEXII X-ray diffractometer was purchased through an NSF CRIF:MU award to Caltech, CHE-0639094. SQUID data were collected at the MMRC of the Beckman Institute of the California Institute of Technology.\n\nSupplemental Material - anie_201005232_sm_miscellaneous_information.pdf
", "abstract": "Copper threesome: A hexapyridyl ligand based upon a 1,3,5-triphenylbenzene framework coordinates three metal centers in a constrained environment (see picture). The tricopper(I) complex reduces dioxygen to form a tricopper(II) cluster. The capping anions affect the magnetism and EPR spectra of these species and reveal a linear dependence between the antiferromagnetic exchange parameter and the Cu-O-Cu angles.", "date": "2011-02-11", "date_type": "published", "publication": "Angewandte Chemie International Edition", "volume": "50", "number": "7", "publisher": "Wiley", "pagerange": "1668-1672", "id_number": "CaltechAUTHORS:20110316-093011185", "issn": "1433-7851", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110316-093011185", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "NSF", "grant_number": "CHE-0639094" } ] }, "doi": "10.1002/anie.201005232", "primary_object": { "basename": "anie_201005232_sm_miscellaneous_information.pdf", "url": "https://authors.library.caltech.edu/records/4wbab-y0741/files/anie_201005232_sm_miscellaneous_information.pdf" }, "resource_type": "article", "pub_year": "2011", "author_list": "Tsui, Emily Y.; Day, Michael W.; et el." }, { "id": "https://authors.library.caltech.edu/records/eb24p-em097", "eprint_id": 21940, "eprint_status": "archive", "datestamp": "2023-08-22 01:41:31", "lastmod": "2023-10-23 15:31:32", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lin-Sibo", "name": { "family": "Lin", "given": "Sibo" }, "orcid": "0000-0001-5922-6694" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Cross-Coupling Chemistry at Mononuclear and Dinuclear Nickel Complexes", "ispublished": "pub", "full_text_status": "public", "keywords": "nickel; cross-coupling; alkyl halides; dinuclear mechanism; metal-arene interactions", "note": "\u00a9 2011 Georg Thieme Verlag Stuttgart. \n\nReceived 12 October 2010. Advanced online publication: 16.12.2010. \n\nWe are grateful to BP, Caltech, and NSF GRFP (S.L.) for financial support.\n\nPublished - Lin2011p12452Synlett.pdf
", "abstract": "Nickel catalysts have been developed for a wide range of\nC\u2013C bond formation reactions. Reaction mechanisms proposed for\nthese transformations generally involve catalytic intermediates\nbased on mononickel species. These reactions are reviewed and the\npossibility of dinickel species active in C\u2013C cross-coupling chemistry\nis discussed.", "date": "2011-01", "date_type": "published", "publication": "Synlett", "volume": "2011", "number": "1", "publisher": "Georg Thieme Verlag", "pagerange": "1-5", "id_number": "CaltechAUTHORS:20110131-144806951", "issn": "0936-5214", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110131-144806951", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "BP" }, { "agency": "Caltech" }, { "agency": "NSF Graduate Research Fellowship" } ] }, "doi": "10.1055/s-0030-1259093", "primary_object": { "basename": "Lin2011p12452Synlett.pdf", "url": "https://authors.library.caltech.edu/records/eb24p-em097/files/Lin2011p12452Synlett.pdf" }, "resource_type": "article", "pub_year": "2011", "author_list": "Lin, Sibo and Agapie, Theodor" }, { "id": "https://authors.library.caltech.edu/records/8qxm0-kkw91", "eprint_id": 23389, "eprint_status": "archive", "datestamp": "2023-08-19 04:50:45", "lastmod": "2023-10-23 19:03:54", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Tsui-Emily-Y", "name": { "family": "Tsui", "given": "Emily Y." }, "orcid": "0000-0001-6419-3954" }, { "id": "Kanady-J-S", "name": { "family": "Kanady", "given": "Jacob S." } }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Trinuclear first row transition metal complexes of a hexapyridyl, trialkoxy 1,3,5-triarylbenzene ligand", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2011 The Royal Society of Chemistry. Received 16th December 2010, Accepted 14th February 2011. We thank Lawrence M. Henling for crystallographic assistance. We are grateful to Caltech, Chemistry Department Dow Fellowship (JSK), and NSF GRFP (EYT) for funding. The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF CRIF:MU award to Caltech, CHE-0639094. SQUID data were collected at the MMRC of the Beckman Institute of the California Institute of Technology.\n\nPublished - Tsui2011p13372Chem_Commun.pdf
Supplemental Material - c0cc05608a.pdf
Supplemental Material - c0cc05608a.txt
", "abstract": "Trinuclear complexes of Mn^(II), Fe^(II), Co^(II), Ni^(II), Cu^(II), and Zn^(II)\nwere synthesized using a ligand architecture based upon a 1,3,5-\ntriarylbenzene core decorated with six pyridines and three\nalkoxide moieties. Characterization via X-ray diffraction,\nNMR, and magnetism studies is discussed.", "date": "2011", "date_type": "published", "publication": "Chemical Communications", "volume": "47", "number": "14", "publisher": "Royal Society of Chemistry", "pagerange": "4189-4191", "id_number": "CaltechAUTHORS:20110420-090320294", "issn": "1359-7345", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110420-090320294", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "NSF", "grant_number": "CHE-0639094" } ] }, "doi": "10.1039/c0cc05608a", "primary_object": { "basename": "c0cc05608a.txt", "url": "https://authors.library.caltech.edu/records/8qxm0-kkw91/files/c0cc05608a.txt" }, "related_objects": [ { "basename": "Tsui2011p13372Chem_Commun.pdf", "url": "https://authors.library.caltech.edu/records/8qxm0-kkw91/files/Tsui2011p13372Chem_Commun.pdf" }, { "basename": "c0cc05608a.pdf", "url": "https://authors.library.caltech.edu/records/8qxm0-kkw91/files/c0cc05608a.pdf" } ], "resource_type": "article", "pub_year": "2011", "author_list": "Tsui, Emily Y.; Kanady, Jacob S.; et el." }, { "id": "https://authors.library.caltech.edu/records/02xgm-6xf72", "eprint_id": 18504, "eprint_status": "archive", "datestamp": "2023-08-19 02:32:49", "lastmod": "2023-10-20 16:27:47", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Velian-A", "name": { "family": "Velian", "given": "Alexandra" } }, { "id": "Lin-Sibo", "name": { "family": "Lin", "given": "Sibo" }, "orcid": "0000-0001-5922-6694" }, { "id": "Miller-A-J-M", "name": { "family": "Miller", "given": "Alexander J. M." } }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" } ] }, "title": "Synthesis and C\u2212C Coupling Reactivity of a Dinuclear Ni^I\u2212Ni^I Complex Supported by a Terphenyl Diphosphine", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2010 American Chemical Society. \n\nReceived March 4, 2010. \n\nWe thank Lawrence M. Henling for crystallographic assistance. We are grateful to Caltech, bp, NSF GRFP (S.L.), and the Caltech SURF Program (A.V.) for funding. The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF CRIF:MU Award to Caltech (CHE-0639094).\n\nSupplemental Material - ja101699a_si_001.pdf
Supplemental Material - ja101699a_si_002.cif
Supplemental Material - ja101699a_si_003.cif
Supplemental Material - ja101699a_si_004.cif
Supplemental Material - ja101699a_si_005.cif
", "abstract": "Mono- and bimetallic complexes of nickel supported by a terphenyl diphosphine have been synthesized. The reported complexes show diverse metal\u2212arene interactions in the solid state. Reactions of an o,o\u2032-biphenyldiyl dinickel complex with CO and dichloroalkanes lead to fluorene derivatives, indicating the formation of carbon\u2212carbon bonds at a bimetallic moiety.", "date": "2010-05-12", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "132", "number": "18", "publisher": "American Chemical Society", "pagerange": "6296-6297", "id_number": "CaltechAUTHORS:20100601-111503988", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100601-111503988", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "British Petroleum" }, { "agency": "NSF Graduate Research Fellowship" }, { "agency": "Caltech Summer Undergraduate Research Fellowship (SURF)" } ] }, "doi": "10.1021/ja101699a", "primary_object": { "basename": "ja101699a_si_001.pdf", "url": "https://authors.library.caltech.edu/records/02xgm-6xf72/files/ja101699a_si_001.pdf" }, "related_objects": [ { "basename": "ja101699a_si_002.cif", "url": "https://authors.library.caltech.edu/records/02xgm-6xf72/files/ja101699a_si_002.cif" }, { "basename": "ja101699a_si_003.cif", "url": "https://authors.library.caltech.edu/records/02xgm-6xf72/files/ja101699a_si_003.cif" }, { "basename": "ja101699a_si_004.cif", "url": "https://authors.library.caltech.edu/records/02xgm-6xf72/files/ja101699a_si_004.cif" }, { "basename": "ja101699a_si_005.cif", "url": "https://authors.library.caltech.edu/records/02xgm-6xf72/files/ja101699a_si_005.cif" } ], "resource_type": "article", "pub_year": "2010", "author_list": "Velian, Alexandra; Lin, Sibo; et el." }, { "id": "https://authors.library.caltech.edu/records/j75qf-7jk28", "eprint_id": 13413, "eprint_status": "archive", "datestamp": "2023-08-22 13:50:02", "lastmod": "2023-10-17 23:52:42", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Bercaw-J-E", "name": { "family": "Bercaw", "given": "John E." } } ] }, "title": "Synthesis and reactivity of tantalum complexes supported by bidentate X2 and tridentate LX2 ligands with two phenolates linked to pyridine, thiophene, furan, and benzene connectors: mechanistic studies of the formation of a tantalum benzylidene and insertion chemistry for tantalum-carbon bonds", "ispublished": "pub", "full_text_status": "public", "keywords": "X-RAY-STRUCTURE; ALKYLIDENE-CENTERED REACTIVITY; ARYL OXIDE LIGATION; CRYSTAL-STRUCTURE; LIVING POLYMERIZATION; ZIRCONIUM COMPLEXES; ARYLDIAMINE LIGAND; PINCER COMPLEXES; PYRIDINE-2,6-BIS(ARYLOXIDE) LIGANDS; NEOPENTYLIDENE COMPLEXES.", "note": "\u00a9 2008 American Chemical Society. Publication Date (Web): November 6, 2008.\nWe thank Lawrence M. Henling (Caltech) for assistance with single crystal X-ray crystallographic studies. This work has been supported by USDOE Office of Basic Energy Sciences (Grant No. DE-FG03-85ER13431).\n\nSupplemental Material - om8002653_si_001.pdf
Supplemental Material - om8002653_si_002.pdf
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Supplemental Material - om8002653_si_004.pdf
Supplemental Material - om8002653_si_005.pdf
Supplemental Material - om8002653_si_006.cif
Supplemental Material - om8002653_si_007.pdf
Supplemental Material - om8002653_si_008.pdf
Supplemental Material - om8002653_si_009.pdf
Supplemental Material - om8002653_si_011.pdf
Supplemental Material - om8002653_si_012.pdf
Supplemental Material - om8002653_si_013.pdf
Supplemental Material - om8002653_si_014.cif
Supplemental Material - om8002653_si_015.pdf
Updated - om8002653_si_010.pdf
", "abstract": "Using either alkane elimination or salt metathesis methods, tantalum complexes have been prepared with new ligand systems with tridentate bis(phenolate)donor (donor = pyridine, furan, and thiophene) or bidentate bis(phenolate)benzene arrangements. The ligand framework has two X-type phenolates connected to the flat heterocyclic L-type donor at the 2,6- or 2,5- positions or to the 2,6- positions of benzene via direct ring\u2212ring (sp_2\u2212sp_2) linkages. Solid-state structures of these complexes show that in all cases the ligands bind in a mer fashion, but with different geometries of the LX_2 frameworks. The pyridine-linked system binds in a Cs-fashion, the furan-linked system in a C2_v-fashion, and the thiophene-linked system in a C_1-fashion. A bis(phenolate)pyridine tantalum tribenzyl species (7), upon heating in the presence of dimethylphenylphosphine, generates a stable benzylidene complex by \u03b1-hydrogen abstraction with loss of toluene and PMe_2Ph trapping. This process was found to be independent of PMe_2Ph concentration with \u0394H = 31.3 \u00b1 0.6 kcal\u00b7mol\u22121 and \u0394S = 3 \u00b1 2 cal\u00b7mol\u22121\u00b7K\u22121, and the kinetic isotope effect kH/kD = 4.9 \u00b1 0.4, consistent with a mechanism involving rate determining \u03b1-hydrogen abstraction with loss of toluene, followed by fast phosphine coordination to the resulting benzylidene species. An X-ray structure determination reveals that the benzylidene \u03c0-bond is oriented perpendicular to the oxygen\u2212oxygen vector, in accord with the prediction of DFT calculations. Tantalum alkyl complexes with the benzene-linked bis(phenolate) ligand (Ta(CH_3)2[(OC_6H_2-tBu_2)2C_6H_3] (16), Ta(CH_2Ph)2[(OC_6H_2-tBu_2)2C_6H_3] (17), and TaCl_2CH_3[(OC_6H_2-tBu_2)2C_6H_4] (18)) are obtained with (to afford pincer complexes) or without cyclometalation at the ipso-position. Deuterium labeling of the phenol hydrogens and of the linking 1,3-benzene-diyl ring reveals an unexpected mechanism for the metalation of bis(phenol)benzene with TaC_l2(CH_3)3 to generate 18. This process involves protonolysis of a methyl group, followed by C-H/Ta-CH_3 \u03c3 bond metathesis leading to cyclometalation of the linking ring, and finally protonation of the cyclometallated group by the pendant phenol. TaCl_2CH_3[(OC_6H_2-tBu_2)2C_6H_4] was found to undergo \u03c3 bond metathesis at temperatures over 90 \u00b0C to give the pincer complex TaCl_2[(OC_6H_2-tBu_2)2C_6H_3] (1_9) and methane (\u0394H = 27.1 \u00b1 0.9 kcal\u00b7mol\u22121; \u0394S\u2260 = \u22122 \u00b1 2 cal\u00b7mol^1\u00b7K^1; k_H/k_D = 1.6 \u00b1 0.2 at 125 \u00b0C). Ta(CH_3)_2[(OC_6H_2-tBu_2)_2C_6H_3] (16) was found to react with tBuNC to insert into the Ta-CH_3 bonds and generate an imino-acyl species (23). Reaction of 16 with Ph_2CO or PhCN leads to insertion into the Ta-Ph bond to give 21 and 22. Complexes 6, 7, 10, 11-P, 12, 13, 17, 18, 19-OEt_2, 21, 22, and 23 have been structurally characterized by single crystal X-ray diffraction, and all show a mer binding mode of the diphenolate ligands, but the ligand geometry varies leading to C_2v-, pseudo-C_s-, pseudo-C_2-, and C_1-symmetric structures.", "date": "2008-12-08", "date_type": "published", "publication": "Organometallics", "volume": "27", "number": "23", "publisher": "American Chemical Society", "pagerange": "6123-6142", "id_number": "CaltechAUTHORS:AGAo08a", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:AGAo08a", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-FG03-85ER13431" } ] }, "doi": "10.1021/om8002653", "primary_object": { "basename": "om8002653_si_004.pdf", "url": "https://authors.library.caltech.edu/records/j75qf-7jk28/files/om8002653_si_004.pdf" }, "related_objects": [ { "basename": "om8002653_si_007.pdf", "url": "https://authors.library.caltech.edu/records/j75qf-7jk28/files/om8002653_si_007.pdf" }, { "basename": "om8002653_si_015.pdf", "url": "https://authors.library.caltech.edu/records/j75qf-7jk28/files/om8002653_si_015.pdf" }, { "basename": "om8002653_si_014.cif", "url": "https://authors.library.caltech.edu/records/j75qf-7jk28/files/om8002653_si_014.cif" }, { "basename": "om8002653_si_005.pdf", "url": "https://authors.library.caltech.edu/records/j75qf-7jk28/files/om8002653_si_005.pdf" }, { "basename": "om8002653_si_006.cif", "url": "https://authors.library.caltech.edu/records/j75qf-7jk28/files/om8002653_si_006.cif" }, { "basename": "om8002653_si_008.pdf", "url": "https://authors.library.caltech.edu/records/j75qf-7jk28/files/om8002653_si_008.pdf" }, { "basename": "om8002653_si_010.pdf", "url": "https://authors.library.caltech.edu/records/j75qf-7jk28/files/om8002653_si_010.pdf" }, { "basename": "om8002653_si_011.pdf", "url": "https://authors.library.caltech.edu/records/j75qf-7jk28/files/om8002653_si_011.pdf" }, { "basename": "om8002653_si_001.pdf", "url": "https://authors.library.caltech.edu/records/j75qf-7jk28/files/om8002653_si_001.pdf" }, { "basename": "om8002653_si_009.pdf", "url": "https://authors.library.caltech.edu/records/j75qf-7jk28/files/om8002653_si_009.pdf" }, { "basename": "om8002653_si_012.pdf", "url": "https://authors.library.caltech.edu/records/j75qf-7jk28/files/om8002653_si_012.pdf" }, { "basename": "om8002653_si_013.pdf", "url": "https://authors.library.caltech.edu/records/j75qf-7jk28/files/om8002653_si_013.pdf" }, { "basename": "om8002653_si_002.pdf", "url": "https://authors.library.caltech.edu/records/j75qf-7jk28/files/om8002653_si_002.pdf" }, { "basename": "om8002653_si_003.cif", "url": "https://authors.library.caltech.edu/records/j75qf-7jk28/files/om8002653_si_003.cif" } ], "resource_type": "article", "pub_year": "2008", "author_list": "Agapie, Theodor; Day, Michael W.; et el." }, { "id": "https://authors.library.caltech.edu/records/0xpcq-hyw39", "eprint_id": 13385, "eprint_status": "archive", "datestamp": "2023-09-15 22:01:41", "lastmod": "2023-10-23 21:39:56", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Henling-L-M", "name": { "family": "Henling", "given": "Lawrence M." } }, { "id": "DiPasquale-A-G", "name": { "family": "DiPasquale", "given": "Antonio G." } }, { "id": "Rheingold-A-L", "name": { "family": "Rheingold", "given": "Arnold L." }, "orcid": "0000-0003-4472-8127" }, { "id": "Bercaw-J-E", "name": { "family": "Bercaw", "given": "John E." } } ] }, "title": "Zirconium and titanium complexes supported by tridentate LX2 ligands having two phenolates linked to furan, thiophene, and pyridine donors: precatalysts for propylene polymerization and oligomerization", "ispublished": "pub", "full_text_status": "public", "keywords": "OSCILLATING METALLOCENE CATALYSTS; AMINE BIS(PHENOLATE) LIGANDS; LIVING POLYMERIZATION; OLEFIN POLYMERIZATION; EXTRA DONOR; PYRIDINE-2,6-BIS(ARYLOXIDE) LIGANDS; 1-HEXENE POLYMERIZATION; PROPENE POLYMERIZATION; ISOBUTYL INITIATORS; CATIONIC ZIRCONIUM.", "note": "\u00a9 2008 American Chemical Society. \n\nPublication Date (Web): 06 November 2008. \n\nThis work has been supported by the USDOE Office of Basic Energy Sciences (Grant No. DEFG03-85ER13431). The authors thank Michael Day (Caltech) for assistance in obtaining the X-ray crystal structures. We are grateful to Mona Shahgholi (Caltech) for help with HRMS and Sara Klamo (Dow) for obtaining the GPC data.\n\nSupplemental Material - om800136y_si_001.pdf?cookieSet=1
Supplemental Material - om800136y_si_002.cif
", "abstract": "Zirconium and titanium complexes with tridentate bis(phenolate)-donor (donor = pyridine, furan and thiophene) ligands have been prepared and investigated for applications in propylene polymerization. The ligand framework has two X-type phenolates connected to the flat heterocyclic L-type donor at the 2,6- or 2.5- positions via direct ring-ring (sp^2-sp^2)linkages. The zirconium and titanium dibenzyl complexes have been prepared by treatment of the neutral bis(phenol)-donor ligands with M(CH_2Ph)_4 (M = Ti, Zr) with loss of 2 equiv of toluene. Titanium complexes with bis(phenolate)pyridine and -furan ligands and zirconium complexes with bis(phenolate)pyridine and -thiophene ligands have been characterized by single-crystal X-ray diffraction. The solid-state structures of the bis(benzyl)titanium complexes are roughly C_2 symmetric, while the zirconium derivatives display C_s and C^1 symmetry. The bis(phenolate)pyridine titanium complexes are structurally affected by the size of the substituents substituents (CMe_3 or CEt_3) ortho to the oxygens, the larger group leading to a larger C_2 distortion. Both titanium and zirconium dibenzyl complexes were found to be catalyst precursors for the polymerization of propylene upon activation with methylaluminoxane (MAO). The activities observed for the zirconium complexes are particularly notable, exceeding 10^6 g polypropylene/mol Zr center dot h in some cases. The bis(phenolate)pyridine titanium analogues are about 10^3 times less active, but generate polymers of higher molecular weight. When activated with MAO, the titanium bis(phenolate)furan and bis(phenolate)thiophene systems were found to promote propylene oligomerization.", "date": "2008-12-08", "date_type": "published", "publication": "Organometallics", "volume": "27", "number": "23", "publisher": "American Chemical Society", "pagerange": "6245-6256", "id_number": "CaltechAUTHORS:AGAo08", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:AGAo08", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-FG03-85ER13431" } ] }, "doi": "10.1021/om800136y", "primary_object": { "basename": "om800136y_si_001.pdf", "url": "https://authors.library.caltech.edu/records/0xpcq-hyw39/files/om800136y_si_001.pdf" }, "related_objects": [ { "basename": "om800136y_si_002.cif", "url": "https://authors.library.caltech.edu/records/0xpcq-hyw39/files/om800136y_si_002.cif" } ], "resource_type": "article", "pub_year": "2008", "author_list": "Agapie, Theodor; Henling, Lawrence M.; et el." }, { "id": "https://authors.library.caltech.edu/records/avt5e-r1c86", "eprint_id": 77452, "eprint_status": "archive", "datestamp": "2023-08-19 21:30:34", "lastmod": "2023-10-25 23:03:48", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Labinger-J-A", "name": { "family": "Labinger", "given": "Jay A." }, "orcid": "0000-0002-1942-9232" }, { "id": "Bercaw-J-E", "name": { "family": "Bercaw", "given": "John E." } } ] }, "title": "Mechanistic Studies of Olefin and Alkyne Trimerization with Chromium Catalysts: Deuterium Labeling and Studies of Regiochemistry Using a Model Chromacyclopentane Complex", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2007 American Chemical Society. \n\nReceived 16 May 2007. Published online 31 October 2007. Published in print 1 November 2007. \n\nWe are grateful to BP Chemicals (then Innovene) and the USDOE Office of Basic Energy Sciences (Grant No. DE-FG03-85ER13431) for financial support of this work.\n\nSupplemental Material - ja073493hsi20070824_075509.pdf
", "abstract": "A system for catalytic trimerization of ethylene utilizing chromium(III) precursors supported by diphosphine ligand PNP^(O4) = (o-MeO\u2212C_6H_4)_2PN(Me)P(o-MeO\u2212C_6H_4)_2 has been investigated. The mechanism of the olefin trimerization reaction was examined using deuterium labeling and studies of reactions with \u03b1-olefins and internal olefins. A well-defined chromium precursor utilized in this studies is Cr(PNP^(O4))(o,o'-biphenyldiyl)Br. A cationic species, obtained by halide abstraction with NaB[C_6H_3(CF_3)_2]_4, is required for catalytic turnover to generate 1-hexene from ethylene. The initiation byproduct is vinylbiphenyl; this is formed even without activation by halide abstraction. Trimerization of 2-butyne is accomplished by the same cationic system but not by the neutral species. Catalytic trimerization, with various (PNP^(O4))Cr precursors, of a 1:1 mixture of C_2D_4 and C_2H_4 gives isotopologs of 1-hexene without H/D scrambling (C_6D_(12), C_6D_8H_4, C_6D_4H_8, and C_6H_(12) in a 1:3:3:1 ratio). The lack of crossover supports a mechanism involving metallacyclic intermediates. Using a SHOP catalyst to perform the oligomerization of a 1:1 mixture of C_2D_4 and C_2H_4 leads to the generation of a broader distribution of 1-hexene isotopologs, consistent with a Cossee-type mechanism for 1-hexene formation. The ethylene trimerization reaction was further studied by the reaction of trans-, cis-, and gem-ethylene-d_2 upon activation of Cr(PNP^(O4))(o,o'-biphenyldiyl)Br with NaB[C_6H_3(CF_3)_2]_4. The trimerization of cis- and trans-ethylene-d_2 generates 1-hexene isotopomers having terminal CDH groups, with an isotope effect of 3.1(1) and 4.1(1), respectively. These results are consistent with reductive elimination of 1-hexene from a putative Cr(H)[(CH_2)_4CH\u2550CH_2] occurring much faster than a hydride 2,1-insertion or with concerted 1-hexene formation from a chromacycloheptane via a 3,7-H shift. The trimerization of gem-ethylene-d2 has an isotope effect of 1.3(1), consistent with irreversible formation of a chromacycloheptane intermediate on route to 1-hexene formation. Reactions of olefins with a model of a chromacyclopentane were investigated starting from Cr(PNP^(O4))(o,o'-biphenyldiyl)Br. \u03b1-Olefins react with cationic biphenyldiyl chromium species to generate products from 1,2-insertion. A study of the reaction of 2-butenes indicated that \u03b2-H elimination occurs preferentially from the ring CH rather than exo-CH bond in the metallacycloheptane intermediates. A study of cotrimerization of ethylene with propylene correlates with these findings of regioselectivity. Competition experiments with mixtures of two olefins indicate that the relative insertion rates generally decrease with increasing size of the olefins.", "date": "2007-11-21", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "129", "number": "46", "publisher": "American Chemical Society", "pagerange": "14281-14295", "id_number": "CaltechAUTHORS:20170515-111025629", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170515-111025629", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "BP Chemicals" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-FG03-85ER13431" } ] }, "doi": "10.1021/ja073493h", "primary_object": { "basename": "ja073493hsi20070824_075509.pdf", "url": "https://authors.library.caltech.edu/records/avt5e-r1c86/files/ja073493hsi20070824_075509.pdf" }, "resource_type": "article", "pub_year": "2007", "author_list": "Agapie, Theodor; Labinger, Jay A.; et el." }, { "id": "https://authors.library.caltech.edu/records/c7z28-gea06", "eprint_id": 74962, "eprint_status": "archive", "datestamp": "2023-08-19 20:26:25", "lastmod": "2023-10-24 23:51:02", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Bercaw-J-E", "name": { "family": "Bercaw", "given": "John E." } } ] }, "title": "Cyclometalated Tantalum Diphenolate Pincer Complexes: Intramolecular C\u2212H/M\u2212CH_3\u03c3-Bond Metathesis May Be Faster than O\u2212H/M\u2212CH_3 Protonolysis", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2007 American Chemical Society. \n\nReceived 23 March 2007. Published online 3 May 2007. Published in print 1 June 2007. \n\nWe thank Dr. Michael W. Day and Lawrence M. Henling (Caltech) for assistance with single-crystal X-ray crystallographic studies. We are grateful to the USDOE Office of Basic Energy Sciences (Grant No. DE-FG03-85ER13431) for financial support.\n\nSupplemental Material - om700284c-file002.pdf
Supplemental Material - om700284c-file003.cif
Supplemental Material - om700284c-file004.cif
", "abstract": "A diphenol linked at the ortho positions to a benzene ring was metalated with TaCl_2(CH_3)_3. Deuterium labeling of the phenol hydrogens and of the linking 1,3-benzenediyl ring reveals an unexpected mechanism involving protonolysis of a methyl group, followed by C\u2212H/Ta\u2212CH_3 \u03c3-bond metathesis, leading to cyclometalation of the linking ring and finally protonation of the cyclometalated group by the pendant phenol.", "date": "2007-06-04", "date_type": "published", "publication": "Organometallics", "volume": "26", "number": "12", "publisher": "American Chemical Society", "pagerange": "2957-2959", "id_number": "CaltechAUTHORS:20170309-085914464", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170309-085914464", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-FG03-85ER13431" } ] }, "doi": "10.1021/om700284c", "primary_object": { "basename": "om700284c-file002.pdf", "url": "https://authors.library.caltech.edu/records/c7z28-gea06/files/om700284c-file002.pdf" }, "related_objects": [ { "basename": "om700284c-file003.cif", "url": "https://authors.library.caltech.edu/records/c7z28-gea06/files/om700284c-file003.cif" }, { "basename": "om700284c-file004.cif", "url": "https://authors.library.caltech.edu/records/c7z28-gea06/files/om700284c-file004.cif" } ], "resource_type": "article", "pub_year": "2007", "author_list": "Agapie, Theodor and Bercaw, John E." }, { "id": "https://authors.library.caltech.edu/records/nzxe6-kv737", "eprint_id": 74955, "eprint_status": "archive", "datestamp": "2023-08-19 19:44:19", "lastmod": "2023-10-24 23:50:35", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Marinescu-S-C", "name": { "family": "Marinescu", "given": "Smaranda C." }, "orcid": "0000-0003-2106-8971" }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Bercaw-J-E", "name": { "family": "Bercaw", "given": "John E." } } ] }, "title": "Group 3 Dialkyl Complexes with Tetradentate (L, L, N, O; L = N, O, S) Monoanionic Ligands: Synthesis and Reactivity", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2007 American Chemical Society. \n\nReceived 21 September 2006. Published online 1 February 2007. Published in print 1 February 2007. \n\nThis work has been supported by USDOE Office of Basic Energy Sciences (Grant No. DE-FG03-85ER13431) and the National Science Foundation (Grant No. CHE-0131180). S.C.M. thanks Caltech's Summer Undergraduate Research Fellowship program for funding. We thank Mr. Lawrence Henling for assistance in obtaining the X-ray crystal structures and Ms. Mona Shahgholi for help with HRMS. We thank Prof. John Arnold for an insightful personal communication regarding the structures of some related complexes supported by ligand 3, particularly one related to 12.\n\nSupplemental Material - om0608612si20061109_015038.cif
Supplemental Material - om0608612si20070108_113222.pdf
", "abstract": "Tripodal, tetradentate phenols, (LCH_2)_2NCH_2-C_6H_2-3,5-(CMe_3)_2-2-OH (L = CH_2OCH_3 (1), CH_2NEt_2 (2), 2-C_5H_4N (3), CH_2SCMe_3 (5), CH_2NMe_2 (6)), were synthesized, and metalations were performed via alkane elimination from yttrium and scandium trialkyl complexes to generate the corresponding dialkyl complexes [(LCH_2CH_2)_2NCH_2-C_6H_2-3,5-(CMe_3)_2-2-O]MR_2 (M = Y, L = OCH_3, R = CH_2SiMe_2Ph (7a); M = Y, L = NEt_2, R = CH_2SiMe_2Ph (7b); M = Sc, L = OCH_3, R = CH_2SiMe_2Ph (8a); M = Sc, L = SCMe_3, R = CH_2SiMe_2Ph (8b); M = Y, L = OCH_3, R = CH_2SiMe_3 (9); M = Sc, L = OCH_3, R = CH_2SiMe_3 (10)). X-ray crystallographic studies show that 7a,b and 8a adopt, in the solid state, mononuclear structures of C_1 symmetry. The ^1H NMR spectra of these dialkyl complexes in benzene-d_6 at high temperatures reveal exchange processes involving the ether groups and the alkyl groups. The dynamic behavior of species 7a, 8a, and 10 in toluene-d8 was investigated by variable-temperature ^1H NMR spectroscopy. The activation parameters of the fluxional processes for 7a, 8a, and 10 were determined by line-shape and Eyring analyses (for 7a, \u0394H^\u29e7 = 7.3 \u00b1 0.3 kcal/mol and \u0394S^\u29e7 = \u221216 \u00b1 1.4 cal/(mol K); for 8a, \u0394H^\u29e7 = 9.9 \u00b1 0.5 kcal/mol and \u0394S^\u29e7 = \u221215.3 \u00b1 1.8 cal/ (mol K); for 10, \u0394H^\u29e7 = 10.8 \u00b1 0.6 kcal/mol and \u0394S^\u29e7 = \u221211.4 \u00b1 1.9 cal/(mol K)). These data establish that the dialkyl complexes 7a, 8a, and 10 undergo a nondissociative exchange process. The scandium dialkyl complex [(C_5H_4N-2-CH_2)_2NCH_2-C_6H_2-3,5-(CMe_3)_2-2-O]Sc(CH_2SiMe_2Ph)_2 (11) was found to undergo clean activation of a C\u2212H bond of a methylene linking a pyridine to the central nitrogen donor. This process follows first-order kinetics (k = [2.8(3)] \u00d7 10^(-4) s^(-1) at 0 \u00b0C). The yttrium dialkyl complexes 7a and 9 react with 1 equiv of [PhNHMe_2]+[B(C_6F_5)_4]- in chlorobenzene-d_5, to generate a solution that slowly polymerizes ethylene. Compounds 7\u221210 also polymerize ethylene with low activity upon activation with MAO.", "date": "2007-02-26", "date_type": "published", "publication": "Organometallics", "volume": "26", "number": "5", "publisher": "American Chemical Society", "pagerange": "1178-1190", "id_number": "CaltechAUTHORS:20170309-082713121", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170309-082713121", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-FG03-85ER13431" }, { "agency": "NSF", "grant_number": "CHE-0131180" }, { "agency": "Caltech Summer Undergraduate Research Fellowship (SURF)" } ] }, "doi": "10.1021/om0608612", "primary_object": { "basename": "om0608612si20061109_015038.cif", "url": "https://authors.library.caltech.edu/records/nzxe6-kv737/files/om0608612si20061109_015038.cif" }, "related_objects": [ { "basename": "om0608612si20070108_113222.pdf", "url": "https://authors.library.caltech.edu/records/nzxe6-kv737/files/om0608612si20070108_113222.pdf" } ], "resource_type": "article", "pub_year": "2007", "author_list": "Marinescu, Smaranda C.; Agapie, Theodor; et el." }, { "id": "https://authors.library.caltech.edu/records/jkw07-jkd10", "eprint_id": 79387, "eprint_status": "archive", "datestamp": "2023-08-19 17:52:15", "lastmod": "2023-10-26 16:10:11", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Day-M-W", "name": { "family": "Day", "given": "Michael W." } }, { "id": "Henling-L-M", "name": { "family": "Henling", "given": "Lawrence M." } }, { "id": "Labinger-J-A", "name": { "family": "Labinger", "given": "Jay A." }, "orcid": "0000-0002-1942-9232" }, { "id": "Bercaw-J-E", "name": { "family": "Bercaw", "given": "John E." } } ] }, "title": "A Chromium-Diphosphine System for Catalytic Ethylene Trimerization: Synthetic and Structural Studies of Chromium Complexes with a Nitrogen-Bridged Diphosphine Ligand with ortho-Methoxyaryl Substituents", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2006 American Chemical Society. \n\nReceived 19 July 2005. Published online 28 April 2006. Published in print 1 May 2006. \n\nWe thank Dr. Steven A. Cohen for helpful discussions. We are grateful to BP Chemicals (now Innovene) for financial support.\n\nSupplemental Material - om050605_2Bsi20050719_022938.cif
Supplemental Material - om050605_2Bsi20050719_022957.cif
Supplemental Material - om050605_2Bsi20050719_023020.cif
Supplemental Material - om050605_2Bsi20060306_114623.pdf
", "abstract": "To gain molecular-level insight into the important features of a chromium-diphosphine catalytic system for ethylene trimerization, the coordination chemistry of chromium with \"PNP\" ligands (PNP^(OMe) = (o-MeOC_6H_4)_2PN(CH_3)P(o-MeOC_6H_4)_2, P^(t-Bu)N^(i-amyl)P_(OMe)) = (2-MeO-4-t-BuC_6H_3)_2PN(i-amyl)P(2-MeO-4-t-BuC_6H_3)_2) has been explored. Chromium(0) carbonyl complexes have been synthesized by CO displacement with diphosphine. Oxidation of Cr(CO)_4{\u03ba^2-(P,P)-(PNP^(OMe))} with I_2, Br_2, and PhICl_2 generates the corresponding chromium(III) halide complexes. Chromium(III) complexes CrCl_3{(\u03ba^3-(P,P,O)-(PNP^(OMe))}, CrCl_3{\u03ba^3-(P,P,O)-(P^(t-)^(Bu)N^(i-amyl)P^(OMe))}, and CrCl_2(CH_3){\u03ba^3-(P,P,O)-(PNP^(OMe))} can be synthesized by metalation with CrCl_3(THF)_3 or CrCl_2(CH_3)(THF)_3. Reaction of CrCl_3{\u03ba^3-(P,P,O)-(PNP^(OMe))} with o,o'-biphenyldiyl diGrignard affords CrBr(o,o'-biphenyldiyl){\u03ba^3-(P,P,O)-(PNP^(OMe))}. Single-crystal X-ray diffraction studies show that the Cr\u2212O and Cr\u2212P distances can vary significantly as a function of metal oxidation state and the other ligands bound to chromium. Variable-temperature ^2H NMR spectroscopy studies of chromium(III) complexes supported by PNP ligands indicate fluxional behavior with the ether groups interchanging at higher temperatures. Low-temperature ^2H NMR spectra are consistent with solution structures similar to the ones determined in the solid state.", "date": "2006-05-22", "date_type": "published", "publication": "Organometallics", "volume": "25", "number": "11", "publisher": "American Chemical Society", "pagerange": "2733-2742", "id_number": "CaltechAUTHORS:20170726-082000200", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170726-082000200", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "BP Chemicals" } ] }, "doi": "10.1021/om050605+", "primary_object": { "basename": "om050605_2Bsi20050719_022938.cif", "url": "https://authors.library.caltech.edu/records/jkw07-jkd10/files/om050605_2Bsi20050719_022938.cif" }, "related_objects": [ { "basename": "om050605_2Bsi20050719_022957.cif", "url": "https://authors.library.caltech.edu/records/jkw07-jkd10/files/om050605_2Bsi20050719_022957.cif" }, { "basename": "om050605_2Bsi20050719_023020.cif", "url": "https://authors.library.caltech.edu/records/jkw07-jkd10/files/om050605_2Bsi20050719_023020.cif" }, { "basename": "om050605_2Bsi20060306_114623.pdf", "url": "https://authors.library.caltech.edu/records/jkw07-jkd10/files/om050605_2Bsi20060306_114623.pdf" } ], "resource_type": "article", "pub_year": "2006", "author_list": "Agapie, Theodor; Day, Michael W.; et el." }, { "id": "https://authors.library.caltech.edu/records/af9b5-ybv56", "eprint_id": 76714, "eprint_status": "archive", "datestamp": "2023-08-19 13:06:48", "lastmod": "2023-10-25 16:44:24", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Schofer-S-J", "name": { "family": "Schofer", "given": "Susan J." } }, { "id": "Labinger-J-A", "name": { "family": "Labinger", "given": "Jay A." }, "orcid": "0000-0002-1942-9232" }, { "id": "Bercaw-J-E", "name": { "family": "Bercaw", "given": "John E." } } ] }, "title": "Mechanistic Studies of the Ethylene Trimerization Reaction with Chromium\u2212Diphosphine Catalysts: Experimental Evidence for a Mechanism Involving Metallacyclic Intermediates", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2004 American Chemical Society. \n\nReceived 9 October 2003. Published online 15 January 2004. Published in print 1 February 2004. \n\nWe thank Drs. Steven A. Cohen, Glenn Sunley, and Duncan F. Wass (BP) for helpful discussions and Michael W. Day and Lawrence M. Henling (Caltech) for assistance with single-crystal X-ray crystallographic studies. We are grateful to BP Chemicals for financial support.\n\nSupplemental Material - ja038968trom20031014_064147.cif
Supplemental Material - ja038968tsi20031118_024350.pdf
", "abstract": "A system for catalytic trimerization of ethylene utilizing CrCl_3(THF)_3 and a diphosphine ligand PNP^(OMe) [=\u2009(o-MeO-C_6H_4)_2PN(Me)P(o-MeO-C_6H_4)_2] has been investigated. The coordination chemistry of chromium with PNP^(OMe) has been explored, and (PNP^(OMe))CrCl_3 and (PNP^(OMe))CrPh_3 (3) have been synthesized by ether displacement from chromium(III) precursors. Salt metathesis of (PNP^(OMe))CrCl_3 with o,o'-biphenyldiyl Grignard affords (PNP^(OMe))Cr(o,o'-biphenyldiyl)Br (4). Activation of 3 with H(Et_2O)_2B[C_6H_3(CF_3)_2]_4 or 4 with NaB[C_6H_3(CF_3)_2]_4 generates a catalytic system and trimerizes a 1:1 mixture of C_2D_4 and C_2H_4 to give isotopomers of 1-hexene without H/D scrambling (C_6D_(12), C_6D_8H_4, C_6D_4H_8, and C_6H_(12) in a 1:3:3:1 ratio). The lack of crossover supports a mechanism involving metallacyclic intermediates. The mechanism of the ethylene trimerization reaction has also been studied by the reaction of trans-, cis-, and gem-ethylene-d_2 with 4 upon activation with NaB[C_6H_3(CF_3)_2]_4.", "date": "2004-02-11", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "126", "number": "5", "publisher": "American Chemical Society", "pagerange": "1304-1305", "id_number": "CaltechAUTHORS:20170419-145525386", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170419-145525386", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "BP Chemicals" } ] }, "doi": "10.1021/ja038968t", "primary_object": { "basename": "ja038968tsi20031118_024350.pdf", "url": "https://authors.library.caltech.edu/records/af9b5-ybv56/files/ja038968tsi20031118_024350.pdf" }, "related_objects": [ { "basename": "ja038968trom20031014_064147.cif", "url": "https://authors.library.caltech.edu/records/af9b5-ybv56/files/ja038968trom20031014_064147.cif" } ], "resource_type": "article", "pub_year": "2004", "author_list": "Agapie, Theodor; Schofer, Susan J.; et el." }, { "id": "https://authors.library.caltech.edu/records/k0v09-ae155", "eprint_id": 90661, "eprint_status": "archive", "datestamp": "2023-08-19 09:18:28", "lastmod": "2023-10-19 14:44:25", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Diaconescu-P-L", "name": { "family": "Diaconescu", "given": "Paula L." }, "orcid": "0000-0003-2732-4155" }, { "id": "Mindiola-D-J", "name": { "family": "Mindiola", "given": "Daniel J." } }, { "id": "Cummins-C-C", "name": { "family": "Cummins", "given": "Christopher C." } } ] }, "title": "Radical Scission of Symmetrical 1,4-Dicarbonyl Compounds:\u00a0 C\u2212C Bond Cleavage with Titanium(IV) Enolate Formation and Related Reactions", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2002 American Chemical Society.\n\nReceived August 9, 2001\n\nFor support of this work, the\nauthors are grateful to the National Science Foundation\n(CHE-9988806), the Packard Foundation (Fellowship to\nC.C.C., 1995-2000), and the National Science Board\n(Alan T. Waterman award to C.C.C., 1998). T.A. thanks\nMIT's UROP (Undergraduate Research Opportunities\nProgram) for funding. The authors are grateful to Prof.\nKarsten Meyer for EPR measurements.\n\nSupplemental Material - om0107284_s.pdf
", "abstract": "Reaction of Ti(NRAr^1)_3 (1, R = C(CH_3)_3, Ar^1 = 3,5-C_6H_3Me_2) with 0.5 equiv of symmetrical 1,4-diketones (ArCOCH_2)_2 (Ar = p-Tol or p-MeOC_6H_4) in hydrocarbon solvents at \u226425 \u00b0C resulted in carbon\u2212carbon bond cleavage with clean formation of titanium-bound enolates, 1-OC(CH_2)Ar. Treatment of Ti(NRAr^1)_3 with esters or amides of succinic acid, under the same mild conditions, smoothly produced titanium(IV) compounds containing the corresponding amide or ester enolate moiety. The amide enolate condenses with benzaldehyde in an aldolic fashion. Differences in the observed reactivity of amido-enolate vs ketone-derived enolate toward aldol condensation were interpreted with the help of computational methods. Upon reaction with Ti(NRAr^1)_3, para-substituted acetophenones yielded equal amounts of enolate and alkoxide products. Under similar experimental conditions, acetophenone itself produced quantitatively a species whose proposed structure incorporates characteristics reminiscent of a Gomberg dimer. This intermediate decomposes cleanly to the expected enolate and alkoxide mixture upon heating. Ti(NRAr^1)_3 reductively complexes substrates such as N-methyl phthalimide. Treatment of Ti(NRAr^1)_3 with 0.5 equiv of o-bromophenyl allyl ether resulted in bromine atom abstraction followed by cyclization of the intermediate aryl radical to generate a titanium-bound 3-methylenedihydrobenzofuran product.", "date": "2002-04-01", "date_type": "published", "publication": "Organometallics", "volume": "21", "number": "7", "publisher": "American Chemical Society", "pagerange": "1329-1340", "id_number": "CaltechAUTHORS:20181106-085445784", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181106-085445784", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-9988806" }, { "agency": "David and Lucile Packard Foundation" }, { "agency": "Massachusetts Institute of Technology (MIT)" } ] }, "doi": "10.1021/om0107284", "primary_object": { "basename": "om0107284_s.pdf", "url": "https://authors.library.caltech.edu/records/k0v09-ae155/files/om0107284_s.pdf" }, "resource_type": "article", "pub_year": "2002", "author_list": "Agapie, Theodor; Diaconescu, Paula L.; et el." }, { "id": "https://authors.library.caltech.edu/records/x1eq5-yr037", "eprint_id": 90662, "eprint_status": "archive", "datestamp": "2023-08-19 09:14:05", "lastmod": "2023-10-19 14:44:31", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Diaconescu-P-L", "name": { "family": "Diaconescu", "given": "Paula L." }, "orcid": "0000-0003-2732-4155" }, { "id": "Cummins-C-C", "name": { "family": "Cummins", "given": "Christopher C." } } ] }, "title": "Methine (CH) Transfer via a Chlorine Atom Abstraction/Benzene-Elimination Strategy:\u00a0 Molybdenum Methylidyne Synthesis and Elaboration to a Phosphaisocyanide Complex", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2002 American Chemical Society. \n\nReceived October 10, 2001. \n\nFor support of this work, the authors are grateful to the National Science Foundation (CHE-9988806), the Packard Foundation (Fellowship to C.C.C., 1995-2000), and the National Science Board (Alan T. Waterman award to C.C.C., 1998). T.A. thanks MIT's UROP (Undergraduate Research Opportunities Program) for funding. The authors thank a referee for drawing attention to ref 12.\n\nSupplemental Material - ja017278r_s1.pdf
Supplemental Material - ja017278r_s2.cif
", "abstract": "Methine (CH) transfer to an open coordination site was achieved in one pot by titanium(III) abstraction of Cl from 7-chloronorbornadiene, radical capture by Mo, and benzene extrusion. This efficient Mo methylidyne synthesis permitted elaboration to an anionic phosphaisocyanide derivative upon deprotonation, functionalization with dichlorophenylphosphine, and ultimate reduction.", "date": "2002-03-20", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "124", "number": "11", "publisher": "American Chemical Society", "pagerange": "2412-2413", "id_number": "CaltechAUTHORS:20181106-085445876", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181106-085445876", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-9988806" }, { "agency": "David and Lucile Packard Foundation" }, { "agency": "Massachusetts Institute of Technology (MIT)" } ] }, "doi": "10.1021/ja017278r", "primary_object": { "basename": "ja017278r_s1.pdf", "url": "https://authors.library.caltech.edu/records/x1eq5-yr037/files/ja017278r_s1.pdf" }, "related_objects": [ { "basename": "ja017278r_s2.cif", "url": "https://authors.library.caltech.edu/records/x1eq5-yr037/files/ja017278r_s2.cif" } ], "resource_type": "article", "pub_year": "2002", "author_list": "Agapie, Theodor; Diaconescu, Paula L.; et el." }, { "id": "https://authors.library.caltech.edu/records/9p2va-hk592", "eprint_id": 90660, "eprint_status": "archive", "datestamp": "2023-08-19 08:34:31", "lastmod": "2023-10-19 14:44:15", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Diaconescu-P-L", "name": { "family": "Diaconescu", "given": "Paula L." }, "orcid": "0000-0003-2732-4155" }, { "id": "Odom-A-L", "name": { "family": "Odom", "given": "Aaron L." } }, { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Cummins-C-C", "name": { "family": "Cummins", "given": "Christopher C." } } ] }, "title": "Uranium\u2212Group 14 Element Single Bonds: Isolation and Characterization of a Uranium(IV) Silyl Species", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2001 American Chemical Society.\n\nReceived June 28, 2001\n\nFor support of this work we are grateful to the National Science Foundation (Grant No. CHE-9988806), the National Science Board (1998 Alan T. Waterman award to C.C.C.), and the Packard Foundation (1995-2000 Fellowship to C.C.C.). P.L.D. thanks Yi-Chou Tsai for a gift of (THF)_3LiSi(SiMe_3)_3.\n\nSupplemental Material - om010575k_s.pdf
", "abstract": "A uranium silyl compound, (Ar[^(t)Bu]N)_(3)USi(SiMe_3)_3 (1; Ar = 3,5-C_(6)H_(3)Me_(2)), has been synthesized, isolated, and characterized structurally and theoretically; compound 1 crystallizes in the space group P3\u0304 and its U\u2212Si interatomic distance was found to be 3.091(3) \u00c5. Geometry optimizations were carried out for the model systems H_3EU(NH_2)_3 (E = C, Si, Ge, Sn) with a set of reasonable constraints; calculated U\u2212E distances and bond energies are in good accord with experimental data.", "date": "2001-11-26", "date_type": "published", "publication": "Organometallics", "volume": "20", "number": "24", "publisher": "American Chemical Society", "pagerange": "4993-4995", "id_number": "CaltechAUTHORS:20181106-085445690", "issn": "0276-7333", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181106-085445690", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-9988806" }, { "agency": "David and Lucile Packard Foundation" } ] }, "doi": "10.1021/om010575k", "primary_object": { "basename": "om010575k_s.pdf", "url": "https://authors.library.caltech.edu/records/9p2va-hk592/files/om010575k_s.pdf" }, "resource_type": "article", "pub_year": "2001", "author_list": "Diaconescu, Paula L.; Odom, Aaron L.; et el." }, { "id": "https://authors.library.caltech.edu/records/nv1b5-e4z10", "eprint_id": 90659, "eprint_status": "archive", "datestamp": "2023-08-19 05:18:58", "lastmod": "2023-10-19 14:44:09", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Agapie-T", "name": { "family": "Agapie", "given": "Theodor" }, "orcid": "0000-0002-9692-7614" }, { "id": "Odom-A-L", "name": { "family": "Odom", "given": "Aaron L." } }, { "id": "Cummins-C-C", "name": { "family": "Cummins", "given": "Christopher C." } } ] }, "title": "In Pursuit of the Molybdenum(III) Tris(thiolate) Fragment:\u00a0 Unusual Structure of a Dimolybdenum \u03bc-Nitrido Complex", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2000 American Chemical Society. \n\nReceived May 6, 1999. \n\nFor funding, C.C.C. is grateful to the National Science Fundation (CAREER Award CHE-9501992), the Alfred P. Sloan Foundation, and the Packard Foundation. T.A. thanks MIT's UROP (Undergraduate Research Opportunities Program) for funding. T.A. is grateful to Daniel J. Mindiola for instructive guidance in single crystal X-ray structure analysis. T.A. also thanks Jane R. Brock and Yi-Chou Tsai for helpful discussions. The authors are grateful to Prof. Luis M. Baraldo for CV measurements.\n\nSupplemental Material - ic9904891.cif
Supplemental Material - ic9904891_s.pdf
", "abstract": "The new molybdenum nitrido\u2212thiolate complex N\u22eeMo(SAd)_3 (Ad = 1-adamantyl) was prepared by a ligand exchange route involving reaction of Ti(SAd)(O^(i)Pr)_3 with Chisholm's nitrido\u2212butoxide complex N\u22eeMo(O^(t)Bu)_3. In an effort to abstract the nitrido nitrogen from N\u22eeMo(SAd)_3, the compound was treated with Mo(N[^(t)Bu]Ph)_3, a three-coordinate molybdenum(III) complex. This resulted in formation of the unusual and thermally unstable (\u03bc-nitrido)dimolybdenum complex (AdS)_3Mo(\u03bc-N)Mo(N[^(t)Bu]Ph)_3, which was isolated and characterized. An X-ray study revealed (AdS)_3Mo(\u03bc-N)Mo(N[^(t)Bu]Ph)_3 to possess an unsymmetrical Mo\u2212(\u03bc-N)\u2212Mo linkage, the Mo\u2212thiolate fragment exhibiting a substantially longer bond to the bridging nitrogen atom. The structure of (AdS)_3Mo(\u03bc-N)Mo(N[^(t)Bu]Ph)_3 is noteworthy, displaying trigonal monopyramidal coordination at the (\u03bc-N)\u2212Mo\u2212thiolate Mo center. Since N\u22eeMo(N[^(t)Bu]Ph)_3 is a good leaving group, (AdS)_3Mo(\u03bc-N)Mo(N[^(t)Bu]Ph)_3 should be a source of the reactive Mo(SAd)_3 fragment. In all the studied reactions of the (\u03bc-nitrido)dimolybdenum complex one of the observed products was N\u22eeMo(N[^(t)Bu]Ph)_3. Two products containing the Mo(SAd)_3 fragment were observed:\u2009 (AdS)_3Mo\u22eeMo(SAd)_3 and [(ON)Mo(\u03bc-SAd)(SAd)_2]_2. Upon treatment with pyridine, the tris(thio-1-adamantyl)(nitrosyl)molybdenum dimer forms the pyridine adduct (AdS)_3Mo(NO)(py), which is a monomer.", "date": "2000-01-24", "date_type": "published", "publication": "Inorganic Chemistry", "volume": "39", "number": "2", "publisher": "American Chemical Society", "pagerange": "174-179", "id_number": "CaltechAUTHORS:20181106-085445584", "issn": "0020-1669", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181106-085445584", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-9501992" }, { "agency": "Alfred P. Sloan Foundation" }, { "agency": "David and Lucile Packard Foundation" }, { "agency": "Massachusetts Institute of Technology (MIT)" } ] }, "doi": "10.1021/ic9904891", "primary_object": { "basename": "ic9904891.cif", "url": "https://authors.library.caltech.edu/records/nv1b5-e4z10/files/ic9904891.cif" }, "related_objects": [ { "basename": "ic9904891_s.pdf", "url": "https://authors.library.caltech.edu/records/nv1b5-e4z10/files/ic9904891_s.pdf" } ], "resource_type": "article", "pub_year": "2000", "author_list": "Agapie, Theodor; Odom, Aaron L.; et el." } ]