Influence of the methyl group at C=C bridging bond of stilbene on the longest wavelength maximum in ultraviolet absorption spectra |
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| Authors: | Yanxiu Zhang Chao‐Tun Cao Jingyuan Zhang Chenzhong Cao |
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| Affiliation: | Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Key Laboratory of QSAR/QSPR of Hunan Provincial University, School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan, China |
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| Abstract: | The compounds stilbenes XArCH=CHArY(XSBY) and 1,2‐diphenylpropylenes XArC(Me)=CHArY(XSMBY) have bridging groups CH=CH and C(CH3)=CH, respectively, in which the C(CH3)=CH has a side‐group CH3 at the carbon‐carbon double bond. A series of XSMBY were synthesized, and their longest wavelength maximum λmax (nm) in ultraviolet absorption spectra were measured in this work. We investigated the change regularity of the νmax (cm‐1, νmax = 1/λmax) of XSMBY and compared it with that of XSBY. The results indicate that (1) there is no good linear relationship between the νmax of XSMBY and that of XSBY. (2) Because of the influence of the side‐group CH3, in case of the same couple of groups X and Y, the λmax of XSMBY is shorter than that of XSBY, that is, it has a blue shift. (3) The cross‐interaction between the side‐group CH3 and Y has an important effect on the νmax of XSMBY, while the cross‐interaction between the side‐group CH3 and X has a little effect on the νmax and can be ignored. (4) The specific cross‐interaction between X and Y has important effect on the νmax of XSMBY, whereas it has no important effect on the νmax of XSBY. |
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| Keywords: | diphenyl propylene side‐group stilbene substituent effect wavelength of ultraviolet absorption |
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