作者:Yasutake Takahashi、Hitoshi Ohaku、Shin-ichi Morishima、Takanori Suzuki、Hiroshi Ikeda、Tsutomu Miyashi
DOI:10.1039/p19960000319
日期:——
The photochemical reactivities of 1,1-diarylspiropentanes 1a–c have been investigated under various photolysis conditions. Upon direct photolysis or acetone-sensitized photolysis, 1 underwent skeletal rearrangement to afford methylidenecyclobutanes 2, 3 and 4. A mechanism involving diradical intermediates has been proposed. Also studied were the photochemical and thermal reactions of the electron donor–acceptor (EDA) complexes of 1 with tetracyanoethylene (TCNE). Photoirradiation of the charge-transfer (CT) absorption bands of the EDA complexes resulted in the skeletal rearrangement of 1 to 2 and 3, with concomitant formation of TCNE adducts 11b,c and 12a–c. The X-ray structure of 11c is reported. A mechanism involving ion radical pairs [1˙+, TCNE˙–] is proposed for the photoreaction. In contrast, no skeletal rearrangement was observed in the thermal reaction of the EDA complexes although 11b and 11c were produced.
在不同的光解条件下,研究了 1,1-二芳基螺戊烷 1a-c 的光化学反应活性。在直接光解或丙酮敏化光解条件下,1 发生骨架重排,生成亚甲基环丁烷 2、3 和 4。研究提出了一种涉及二叉中间体的机理。此外,还研究了 1 的电子供体-受体(EDA)复合物与四氰基乙烯(TCNE)的光化学反应和热反应。光照射 EDA 复合物的电荷转移(CT)吸收带,导致 1 的骨架重排为 2 和 3,同时形成 TCNE 加合物 11b、c 和 12a-c。报告了 11c 的 X 射线结构。提出了涉及离子自由基对[1˙+, TCNE˙-]的光反应机制。相比之下,虽然生成了 11b 和 11c,但在 EDA 复合物的热反应中没有观察到骨架重排。