Single Electron Transfer-Promoted Photocyclization Reactions of Linked Acceptor−Polydonor Systems: Effects of Chain Length and Type on the Efficiencies of Macrocyclic Ring-Forming Photoreactions of Tethered α-Silyl Ether Phthalimide Substrates
作者:Dae Won Cho、Jung Hei Choi、Sun Wha Oh、Chunsheng Quan、Ung Chan Yoon、Runtang Wang、Shaorong Yang、Patrick S. Mariano
DOI:10.1021/ja076846l
日期:2008.2.1
center to the terminal alpha-trimethylsilyl ether position. In addition, an inverse relationship was observed between the quantum yields of photocyclization reactions of the tethered phthalimides and naphthalimides and the length of the polyethylenoxy chain. Finally, the roles played by chain type and length in governing photoreaction efficiencies were investigated by using intramolecular competition
描述了一项调查结果,旨在获得有关控制单电子转移 (SET) 促进的连接受体-多供体系统的光环化反应效率的因素的信息。在这项工作中使用的一组基材包括 α-三甲基甲硅烷基醚封端、聚亚甲基和聚亚乙基氧基连接的邻苯二甲酰亚胺和 2,3-萘二甲酰亚胺。观察到聚氧乙烯连接的邻苯二甲酰亚胺和萘二甲酰亚胺的光环化反应以更高的化学产率和更大的量子效率发生,而不是含有几乎相等长度的聚亚甲基系链的类似物。这些发现表明,1、在光环化过程中作为关键中间体的 omega-两性离子双自由基在链中含有氧供体位点的物质中得到增强。研究结果表明,这些供体位点促进初始 SET 到受体激发态和随后的链内 SET,导致阳离子自由基中心迁移到末端 α-三甲基甲硅烷基醚位置。此外,在系留邻苯二甲酰亚胺和萘二甲酰亚胺的光环化反应的量子产率与聚氧乙烯链的长度之间观察到反比关系。最后,通过在聚氧乙烯和聚亚甲基双系邻苯二甲酰亚胺的光反应中使用