[
    {
        "id": "authors:sybs5-ap024",
        "collection": "authors",
        "collection_id": "sybs5-ap024",
        "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170606-123544330",
        "type": "article",
        "title": "CF_3 Rotation in 3-(Trifluoromethyl)phenanthrene: Solid State ^(19)F and ^1H NMR Relaxation and Bloch\u2212Wangsness\u2212Redfield Theory",
        "author": [
            {
                "family_name": "Beckmann",
                "given_name": "Peter A.",
                "clpid": "Beckmann-P-A"
            },
            {
                "family_name": "Rosenberg",
                "given_name": "Jessie",
                "clpid": "Rosenberg-J"
            },
            {
                "family_name": "Nordstrom",
                "given_name": "Kerstin",
                "clpid": "Nordstrom-K"
            },
            {
                "family_name": "Mallory",
                "given_name": "Clelia W.",
                "clpid": "Mallory-C-W"
            },
            {
                "family_name": "Mallory",
                "given_name": "Frank B.",
                "clpid": "Mallory-F-B"
            }
        ],
        "abstract": "We have observed and modeled the ^1H and ^(19)F solid-state nuclear spin relaxation process in polycrystalline 3-(trifluoromethyl)phenanthrene. The relaxation rates for the two spin species were observed from 85 to 300 K at the low NMR frequencies of \u03c9/2\u03c0 = 22.5 and 53.0 MHz where CF3 rotation, characterized by a mean time \u03c4 between hops, is the only motion on the NMR time scale. All motional time scales (\u03c9\u03c4 \u226a 1, \u03c9\u03c4 \u2248 1, and \u03c9\u03c4 \u226b 1) are observed. The ^1H spins are immobile on the NMR time scale but are coupled to the ^(19)F spins via the unlike-spin dipole\u2212dipole interaction. The temperature dependence of the observed relaxation rates (the relaxation is biexponential) shows considerable structure and a thorough analysis of Bloch\u2212Wangsness\u2212Redfield theory for this coupled spin system is provided. The activation energy for CF_3 rotation is 11.5 \u00b1 0.7 kJ/mol, in excellent agreement with the calculation in a 13-molecule cluster provided in the companion paper where the crystal structure is reported and detailed ab initio electronic structure calculations are performed [Wang, X.; Mallory F. B.; Mallory, C. W; Beckmann, P. A.; Rheingold, A. L.; Francl, M. M J. Phys. Chem. A 2006, 110, 3954].",
        "doi": "10.1021/jp056643o",
        "issn": "1089-5639",
        "publisher": "American Chemical Society",
        "publication": "Journal of Physical Chemistry A",
        "publication_date": "2006-03-23",
        "series_number": "11",
        "volume": "110",
        "issue": "11",
        "pages": "3947-3953"
    },
    {
        "id": "authors:1ye1x-q8a89",
        "collection": "authors",
        "collection_id": "1ye1x-q8a89",
        "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151020-124114951",
        "type": "article",
        "title": "Small-Ring Compounds. XXX. Reactions of Phenylcyclobutadienoquinone with Methanol",
        "author": [
            {
                "family_name": "Mallory",
                "given_name": "Frank B.",
                "clpid": "Mallory-F-B"
            },
            {
                "family_name": "Roberts",
                "given_name": "John D.",
                "clpid": "Roberts-J-D"
            }
        ],
        "abstract": "The thermal reaction of phenylcyclobutadienoquinone (I) with methanol gives 2,4-dimethoxy-3-phenylcyclobutenone The relative A possible mechanism is presented that accounts for the 2-hydroxy-2-methoxy-3-phenylcyclobutenon(IV). (II), 3-phenyl-4-hydroxy-4-methoxy-2-butenoiaccid lactone (III) and dimethyl phenylsuccinate (IV). The relative yields of the three products depend on the reaction temperature. A possible mechanism is presented that accounts for the formation of the three products by way of a common intermediate: 2-hydroxy-2-methoxy-3-phenylcyclobutenone (V). The structures of II and III were established by spectroscopic analysis, chemical degradation and independent synthesis.",
        "doi": "10.1021/ja01463a034",
        "issn": "0002-7863",
        "publisher": "American Chemical Society",
        "publication": "Journal of the American Chemical Society",
        "publication_date": "1961-01-01",
        "series_number": "2",
        "volume": "83",
        "issue": "2",
        "pages": "393-397"
    }
]