Whitesides, George M. and Kaplan, Fred and Nagarajan, K. and Roberts, John D. (1962) Nuclear Magnetic Resonance Spectroscopy: Abnormal Splitting of Ethyl Groups Due to Molecular Asymmetry, III. Proceedings of the National Academy of Sciences of the United States of America, 48 (7). pp. 1112-1114. ISSN 0027-8424. http://resolver.caltech.edu/CaltechAUTHORS:WHIpnas62
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The protons of a methylene group removed by one or more bonds from a center of molecular asymmetry may be magnetically nonequivalent and display AB-type nuclear magnetic resonance (n.m.r.) spectra [1-4]. It has been suggested that the chemical shift between the two methylene protons arises from unequal populations of the possible rotational conformations. However, even assuming equal populations and rapid interconversion of the three conformers I, II, and III, Ha and Hb are always distinct and identifiable, since no two conformers are identical except for interchange of Ha and Hb [5,6]. This "intrinsic asymmetry" of the methylene group might also be the cause of the observed magnetic nonequivalence of the methylene protons.
|Additional Information:||Copyright © 2005 by the National Academy of Sciences Communicated May 11, 1962 Supported in part by the Office of Naval Research and the National Science Foundation. Gates and Crellin Laboratories of Chemistry Contribution No. 2842.|
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|Deposited On:||27 Nov 2006|
|Last Modified:||14 Nov 2014 19:19|
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