光敏电子转移异构反应中的盐效应

Salt Effect in Photoinduced Electron Transfer Isomerization Reaction

本文利用四正丁基四氟硼酸铵为探针,研究了顺式芪和四环烷的9,10-二氰基蒽敏化光异构化的反应机理.加入四正丁基四氟硼酸铵明显加快顺式芪的异构反应而减慢四环烷的反应.荧光猝灭及激光闪光光解实验证明四正丁基四氟硼酸铵能促进电荷分离过程而生成离子自由基对.从而证实顺式芪的异构化反应是经由离子自由基的历程,而四环烷则是通过激基复合物机理.

n-Bu_4NBF_4 was used as a probe to investigate the mechanism of 9, 10-dicyanoanthracene sensitized isomerization of cis-stilbene and quadrieyclane. Addition of n-Bu_4NBF_4 accelerated the isomerization of cis-stilbene dramatically but retarded the reaction of quadrieyolane. Fluorescence quenching and flash photolysis experiment proved that n-Bu_4NBF_4 could cause the dissociation of the exciplex to form separated radical ions effectively. It was verified that the isomerizations of cis-stilbene and quadricyclane are via radical ion and via the exciplex respectively.