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Substituent effects on one-bond 15N13C couplings in N,N-dimethylanilines and nitrobenzenes. Effect of steric inhibition of conjugation

✍ Scribed by T. Axenrod; C. M. Watnick; M. J. Wieder; S. Duangthai; G. A. Webb; H. J. C. Yeh; S. Bulusu; M. M. King

Publisher
John Wiley and Sons
Year
1982
Tongue
English
Weight
466 KB
Volume
20
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

The ^1^J(^15^N^13^C) values for a series of ring‐substituted N,N‐dimethylaniline‐^15^N derivatives and a series of nitrobenzene‐^15^N derivatives were measured from the ^13^C spectra. In the nitrobenzenes, small changes in ^1^J(^15^N^13^C) are attributed to the inductive effect of the substituents, since steric inhibition of conjugation has little effect on the magnitude of the coupling. In contrast, steric inhibition of nitrogen lone‐pair delocalization in N,N‐dimethylaniline derivatives markedly reduces the value of ^1^J(^15^N^13^C). Theoretical calculations of ^1^J(^15^N^13^C) values for the two series of compounds were made using standard INDO parameters and a ‘sum‐over‐states’ perturbation approach. Fair agreement between the calculated and experimental values is found.

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