Effect of substituent on the UV-Vis spectra: an extension from disubstituted to multi-substituted benzylideneanilines

摘要

For studying the substituent effects on the nu(max) of substituted benzylideneanilines (XBAYs) systematically, 12 samples of 3,3'-disubstituted XBAYs and 52 samples of multi-substituted XBAYs were synthesized, and the substituent effects on their nu(max) were investigated in this paper. A modified regression equation quantifying the nu(max) of 4,4'/4,3'/3,4'/3,3'-disubstituted and multi-substituted XBAYs (shown as Eq. 3) was obtained. The results showed that the substituent effects on the nu(max) of 3,3'-substituted and multi-substituted XBAYs became more complicated. In Eq. 3, the contributions of the meta-parameters to the nu(max) of XBAYs were different from those of the corresponding para-parameters. For the substituent cross-interaction effects, there is no difference whatever the substituents are at meta-position or para-position. Compared with Eq. 1, Eq. 3 obtained in this paper has a wider application and more accuracy in quantifying the nu(max) of substituted XBAYs. Copyright (C) 2016 John Wiley & Sons, Ltd.