Comparison of the 13C (C = N) chemical shifts of substituted N‐(phenyl‐ethylene)‐anilines and substituted N‐(benzylidene)‐anilines |
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| Authors: | Zhongzhong Cao Chaotun Cao Chenzhong Cao |
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| Affiliation: | 1. School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan, China;2. Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Hunan University of Science and Technology, Xiangtan, China |
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| Abstract: | Comparison of 13C NMR of C = N bond chemical shifts δC(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 δC(C = N) of 61 samples of XPEAYs were measured, and the substituent effect on their δC(C = N) were investigated. The results show the factors affecting the δC(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 δC(C = N), while the conjugative effect of them have very little effect on the δC(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 δC(C = N). Also, the excited‐state substituent parameter of substitute Y has certain contribution to the δC(C = N). Copyright © 2015 John Wiley & Sons, Ltd. |
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| Keywords: | 13C NMR chemical shifts excited‐state substituent parameter inductive effect of substituent N‐(phenyl‐ethylene)‐anilines substituent specific cross‐interaction effect |
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