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Vector Model for Indirect Proton Hyperfine Interactions in π-Electron Radicals

McConnell, Harden M. (1957) Vector Model for Indirect Proton Hyperfine Interactions in π-Electron Radicals. Proceedings of the National Academy of Sciences of the United States of America, 43 (8). pp. 721-723. ISSN 0027-8424.

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Significant information on unpaired electron distributions in molecules, liquids, and solids can sometimes be obtained from magnetic resonance studies of electron-nucleus hyperfine interactions. A particularly important problem in this field involves the proton hyperfine interactions that have been observed in the electron magnetic resonance spectra of a large number of aromatic radicals in solution [1-3]. The problem concerns the theoretical basis for a proposal that the observed hyperfine splitting aN due to aromatic proton N in an aromatic radical can be used to estimate the unpaired spin density ρN at carbon atom N to which proton N is attached, according to the equation [2,4-6] aN = QρN. (1) A semiempirical value of Q derived from observed splittings aN and theoretically calculated spin densities ρN is -30 ± 5 gauss, or -85 ± 15 Mc [2]. Equation (1) has been derived recently using molecular orbital theory with arbitrary π-π configuration interaction [6]. We show here how the simple proportionality in equation (1) may be derived using the Dirac vector model.

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Additional Information:Copyright © 1957 by the National Academy of Sciences Communicated by Richard M. Badger, June 24, 1957 Supported in part by the Office of Ordnance Research, U.S. Army. Gates and Crellin Laboratories of Chemistry, Contribution No. 2214.
Issue or Number:8
Record Number:CaltechAUTHORS:MCCpnas57
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:6931
Deposited By: Archive Administrator
Deposited On:03 Jan 2007
Last Modified:02 Oct 2019 23:37

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