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The use of 13 C satellites in proton spectra for a study of the r α structure and of the internal rotation of p ‐chlorotoluene partially oriented in nematic phases
Author(s) -
Diehl P.,
Moia F.
Publication year - 1981
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270150326
Subject(s) - isotropy , proton , spectral line , chemistry , molecule , benzene , resonance (particle physics) , bond length , kinetic isotope effect , nuclear magnetic resonance , molecular physics , crystallography , analytical chemistry (journal) , atomic physics , physics , deuterium , nuclear physics , optics , organic chemistry , astronomy , chromatography
The proton magnetic resonance spectra with natural abundance 13 C satellites of p ‐chlorotoluene in isotropic as well as in oriented solvents are analyzed. The indirect CH and HH couplings are determined from the isotropic sample and one bond 13 C isotope effects on the proton chemical shifts are measured. The direct couplings derived from the oriented samples are corrected for harmonic vibration and used to determine the molecular r α structure with a 6‐fold hindering potential for the methl group. The resulting CH and CC bond lengths have errors which are smaller than 0.002Å. They deviate from the unsubstituted benzene molecule by between −1.1 and −0.5% for the CH and between +0.3 and +0.5% for the CC distances. It is not possible to obtain conclusive information about the hindering potential.