Influence Of Substituent Effects On The Spectral Properties Of 1,2-diphenylpropylenes

44 samples of target compounds 1,2-diphenylpropylenes XArC?Me?=CHArY?XSMBY?were synthesized in this work.Their melting point,H NMR spectrum,C NMR spectrum,UV-Visible absorption spectrum,reduction potential and infrared absorption spectrum were determined.The effects of substituents on the spectral properties of the target compounds were studied by using the method of quantitative structure-property relationship.From quantitative correlation analysis of ?_max of XSMBY and comparing the change regularity of their ?_max with that of XSBY?XArCH=CHArY?,we can obtain that there is no linear relationship between the ?_max of XSMBY and that of XSBY,and the factors influencing the ?_max of them are different.The addition of methyl group to the bridging group makes the ground-state polar electronic effect???also has important effects on the ?_max of XSMBY,whereas the influence of the ? constants of X and Y on the ?_max of XSBY is negligible.For the compounds XSMBY and XSBY,their ?_max can be quantified by a general equation,and the equation has good correlation.The steric effect resulting from the methyl group at the bridging group contributes a blue shift effect to the ?_max of XSMBY.The substituent effects on the 13 C NMR chemical shifts ?C of the bridging group for XSMBY were quantitatively investigated,and compared it with that of Schiff base compounds.Three quantitative correlation equations of XSMBY were proposed by regression analysis,and their correlation coefficients were 0.9955,0.9974 and 0.9701,respectively.They were successfully applied to predict the chemical shifts of compounds,and good results were obtained.The addition of methyl group to the bridging group makes the group has somewhat polar,but the effect of substituents on it is different from that of Schiff base compounds.For the bridge carbon on the X side ?C?X?,the conjugate effect of substituent X makes the most contribution;For the bridge carbon on the Y side ?C?Y?,the induction effect of substituent X,the conjugate effect of substituent X,and the induction effect of substituent Y also play an important role;For the methyl carbon on the bridge bond ?C?Me?,in addition to the Hammett constant,the excited state substituent constants are also important factors.The change regularity of the reduction potentials?Ered?of XSMBY was studied.In addition to the Hammett constant and the excited state substituent constant,the cross-interaction between the side-group CH3 and Y has important effect on the Ered.Its influence factors are obviously different from that of Schiff base compounds,and the correlation equation of Schiff base can not be used to quantify the the change regularity of XSMBY.The C=C bridging bond of stilbene is more difficult to be reduced than the C=N of Schiff base.The change regularity of the infrared absorption frequency of ?C=C in XSMBY was studied.The results showed that the infrared absorption frequency of ?C=C can be quantified by a six parameters equation which has good correlation.Its correlation coefficients reached 0.9158.In addition to the Hammett constant and the excited state substituent constant,the cross-interaction between the side-group CH3 and X has important effect on the ?C=C and the influence is the most important.