取代基效应对二取代二苯基硝酮还原电位的影响  

Effects of Substituents on Reduction Potentials of Disubstituted N-Phenyl-α-phenylnitrones

作　　者：罗青青[1] 曹朝暾[1] 曹晨忠[1] 

机构地区：[1]湖南科技大学化学化工学院理论有机化学与功能分子教育部重点实验室分子构效关系湖南省普通高校重点实验室,湖南湘潭411201

出　　处：《物理化学学报》2016年第7期1691-1698,共8页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(21272063);湖南省教育厅科研项目(14C0466);湖南省自然科学基金(14JJ3112)资助~~

摘　　要：合成了36种二取代二苯基硝酮XAr CH=N(O)Ar Y(简称XPNY)化合物,研究了取代基效应对其还原电位(E_(red))的影响,并系统对比了XPNY与XAr CH=NAr Y(简称XBAY)和XAr C(Me)=NAr Y(简称XPEAY)还原电位的差异。研究结果表明:XPNY的E_(red)与C=N键的13C NMR化学位移δC(C=N)没有线性关系;XPNY、XBAY和XPEAY三类化合物的E_(red)之间没有线性关系,表现出不同的变化规律;X基团的激发态取代基效应和间位基团位置指示变量对化合物XPEAY和XBAY的E_(red)都有贡献,而对化合物XPNY的E_(red)贡献都很小,可忽略;Y基团的激发态取代基效应对化合物XPNY的E_(red)有一定贡献,而对化合物XPEAY和XBAY的E_(red)贡献很小,可忽略;XBAY和XPNY的母体有近似的还原电位,而XPEAY的母体其还原电位更低,一般而言,X-Y基团对相同时,XPEAY化合物更难被还原。Thirty-six samples of disubstituted N-phenyl- α-phenylnitrones, XAr CH = N（O）Ar Y（XPNY）, were synthesized. The effects of their substituents on their reduction potentials（E（red）） were investigated by systematically comparing the E（red）differences for XPNY versus XAr CH = NAr Y（XBAY） and XPNY versus XAr C（Me）=NAr Y（XPEAY）. The results show the following： there is no linear relationship between the E（red）values and13 C NMR chemical shifts, δC（C=N）, of the C=N bridging bond for XPNY; there are no linear relationships among the E（red）values for XPNY versus XBAY and XPNY versus XPEAY, i.e., their E（red）values show their own specific regular changes; the excited-state substituent effect of X and the indicating parameter of the metaposition group make important contributions to the E（red）values of XPEAY and XBAY, but have little effect on E（red） of XPNY; the excited-state substituent effect of the Y group contributes to the XPNY E（red）, but rarely contributes to the E（red）values of XPEAY and XBAY, and can be ignored; the parents of XBAY and XPNY have similar reduction potentials, but the reduction potential of the parent of XPEAY is lower than those of XBAY and XPNY. In general,XPEAY is more difficult to be reduced than XBAY or XPNY, for these three types of compound with X-Y group couples.

关 键 词：二苯基硝酮 取代基效应 化学位移 还原电位 激发态取代基参数 指示变量 

分 类 号：O625.42[理学—有机化学]