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Comparison of the 13 C (C = N) chemical shifts of substituted N ‐(phenyl‐ethylene)‐anilines and substituted N ‐(benzylidene)‐anilines
Author(s) -
Cao Zhongzhong,
Cao Chaotun,
Cao Chenzhong
Publication year - 2015
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.3450
Subject(s) - substituent , chemistry , ethylene , chemical shift , medicinal chemistry , stereochemistry , computational chemistry , organic chemistry , catalysis
Comparison of 13 C NMR of C = N bond chemical shifts δ C (C = N) in substituted N ‐(phenyl‐ethylene)‐anilines XArC(Me) = NArY (XPEAYs) with that in substituted N ‐(benzylidene)‐anilines XArCH = NArY (XBAYs) was carried out. The δ C (C = N) of 61 samples of XPEAYs were measured, and the substituent effect on their δ C (C = N) were investigated. The results show the factors affecting the δ C (C = N) of XPEAYs are quite different from that of XBAYs. A penta‐parameter correlation equation was obtained for the 61 compounds, which has correlation coefficient 0.9922 and standard error 0.12 ppm. The result indicates that, in XPEAYs, the inductive effects of substituents X and Y are major factors affecting the δ C (C = N), while the conjugative effect of them have very little effect on the δ C (C = N) and can be ignored. The substituent‐specific cross‐interaction effects between X and Y and between Me of C = N bond and substituent Y are important factors affecting the δ C (C = N). Also, the excited‐state substituent parameter of substitute Y has certain contribution to the δ C (C = N). Copyright © 2015 John Wiley & Sons, Ltd.