Laser Photolysis Studies on [2+2]-Photocycloreversion and Photoisomerization Reactions of<i>trans</i>- and<i>cis</i>-1,2-Di(1-pyrenyl)cyclobutane Dimers through Radical Ion Intermediates
作者:Akira Tsuchida、Masahide Yamamoto、Yasunori Nishijima
DOI:10.1246/bcsj.64.3402
日期:1991.11
Transient radical ion intermediates of [2+2]-photocycloreversion and photoisomerization reactions of the 1-vinylpyrene (1) cyclobutane dimers, trans- and cis-1,2-di(1-pyrenyl)cyclobutanes (2t and 2c, respectively), were studied by nanosecond laser photolysis measurements; the reaction quantum yields were determined by photoproduct analysis. The excited singlet state of dimers 2t and 2c was quenched
1-乙烯基芘(1)环丁烷二聚体、反式和顺式-1,2-二(1-芘基)环丁烷(分别为2t和2c)的[2+2]-光环转化和光异构化反应的瞬态自由基离子中间体,通过纳秒激光光解测量进行研究;反应量子产率通过光产物分析确定。二聚体 2t 和 2c 的激发单线态被电子受体 1,4-二氰基苯猝灭,在极性乙腈溶剂中扩散控制速率。系统中二聚体的瞬态吸收光谱显示芘发色团的二聚体自由基阳离子的形成,其正电荷在两个芘环中离域。二聚体通过二聚体自由基阳离子裂解形成 1。相比之下,在电子供体 N,N-二甲基-对甲苯胺的淬灭过程中无法观察到二聚体自由基阴离子的形成。二聚体从阴离子物质的裂解产率低。电子密度的降低...