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Influence of the methyl group at C=C bridging bond of stilbene on the longest wavelength maximum in ultraviolet absorption spectra
Author(s) -
Zhang Yanxiu,
Cao ChaoTun,
Zhang Jingyuan,
Cao Chenzhong
Publication year - 2017
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.3705
Subject(s) - chemistry , ultraviolet , spectral line , wavelength , side chain , absorption spectroscopy , absorption (acoustics) , double bond , stereochemistry , crystallography , organic chemistry , polymer , optics , physics , astronomy
The compounds stilbenes XArCH=CHArY(XSBY) and 1,2‐diphenylpropylenes XArC(Me)=CHArY(XSMBY) have bridging groups CH=CH and C(CH 3 )=CH, respectively, in which the C(CH 3 )=CH has a side‐group CH 3 at the carbon‐carbon double bond. A series of XSMBY were synthesized, and their longest wavelength maximum λ max (nm) in ultraviolet absorption spectra were measured in this work. We investigated the change regularity of the ν max (cm ‐1 , ν max = 1/λ max ) of XSMBY and compared it with that of XSBY. The results indicate that (1) there is no good linear relationship between the ν max of XSMBY and that of XSBY. (2) Because of the influence of the side‐group CH 3 , in case of the same couple of groups X and Y, the λ max of XSMBY is shorter than that of XSBY, that is, it has a blue shift. (3) The cross‐interaction between the side‐group CH 3 and Y has an important effect on the ν max of XSMBY, while the cross‐interaction between the side‐group CH 3 and X has a little effect on the ν max and can be ignored. (4) The specific cross‐interaction between X and Y has important effect on the ν max of XSMBY, whereas it has no important effect on the ν max of XSBY.