dichloromethane. The benzhydryl cations were generated by laser flash photolysis of quaternary phosphonium and ammonium tetrafluoroborates. For most reactions, exponential decays of the absorbances of the benzhydryl cations were observed because the carbocations were generated in the presence of a high excess of the amines (pseudo‐first‐order conditions). From the linear plots of kobs versus the amine
已在
乙腈和
乙腈中研究了叔胺,
三乙胺(1a),
N-甲基吡咯烷(1b),
N-甲基哌啶(1c)和
N-甲基吗啉(1d)与苯甲基
铵离子(Ar 2 CH +)反应的动力学。
二氯甲烷。苯甲基阳离子是通过季laser和四
氟硼酸铵的激光快速光解法产生的。在大多数反应中,观察到苯甲基阳离子的吸光度呈指数衰减,因为碳阳离子是在大量过量的胺存在下产生的(伪一级条件)。从的线性图k obs 与胺浓度的关系,获得了二级速率常数k,这使我们能够计算出CH 3 CN和CH 2 Cl 2中这些胺的N和s。因此,线性自由能关系log k = s(N + E)被用于将1a–d整合到我们全面的亲核标度中。版权所有©2010 John Wiley&Sons,Ltd.