substitution. Introduction of sulfur at the β-position of the flexible alkyl chain reverses this trend, whereas such substitution at the α-position has negligible effect. This is rationalized in terms of the three electron two center bonds, favorable due to the formation of five-membered cyclic radical cations in the case of β-substitution, which is supported by DFT computations.
纳秒激光闪光光解(LFP)实验表明,2-烷基二
噻吩对三联体
二苯甲酮的ET猝灭速率随着取代的增加而显着降低。在柔性烷基链的β-位引入
硫可逆转这种趋势,而在α-位的这种取代作用可忽略不计。就三个电子两个中心键而言,这是合理的,这是有利的,因为在β取代的情况下会形成五元环自由基阳离子,这得到了DFT计算的支持。