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Improved 13 C NMR Shift Prediction Program for Polysubstituted Benzenes and Sterically Defined Cyclohexane Derivatives
Author(s) -
Hönig H.
Publication year - 1996
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/(sici)1097-458x(199605)34:5<395::aid-omr886>3.0.co;2-q
Subject(s) - chemistry , steric effects , cyclohexane , conformational isomerism , chemical shift , carbon 13 nmr , computational chemistry , stereochemistry , organic chemistry , molecule
By introduction of pair‐induced chemical shift correction increments for 13 C NMR shifts of disubstituted aromatics, the average absolute difference between observed and calculated shifts can be lowered from 3 to less than 0.5 ppm. Thus the erroneous assignment of some polysubstituted aromatics in the literature could be corrected. Up to now, the following substituents have been included in a Windows program: Br, CH 2 OH, CH 3 , CHO, Cl, CN, COCH 3 , COOCH 3 , NH 2 , NO 2 , OCH 3 , OCOCH 3 and OH. The same substituents have also been included for sterically defined polysubstituted cyclohexane derivatives via the introduction of separate axial and equatorial shift increments together with a population analysis of the possible conformers.