Organogermanium Reactive Intermediates. The Direct Detection and Characterization of Transient Germylenes and Digermenes in Solution
作者:William J. Leigh、Cameron R. Harrington、Ignacio Vargas-Baca
DOI:10.1021/ja046308y
日期:2004.12.1
Diphenylgermylene (Ph2Ge) and its Ge=Ge doubly bonded dimer, tetraphenyldigermene (6a), have been characterized directly in solution for the first time by laser flash photolysis methods. The germylene is formed via (formal) cheletropic photocycloreversion of 3,4-dimethyl-1,1-diphenylgermacyclopent-3-ene (4a), which is shown to proceed in high chemical (>95%) and quantum yield (phi = 0.62) by steady-state
Diphenylgermylene (Ph2Ge) 及其 Ge=Ge 双键二聚体四苯基二锗烯 (6a) 首次通过激光闪光光解方法直接在溶液中表征。锗烯是通过 3,4-二甲基-1,1-二苯基锗环戊-3-烯 (4a) 的(正式)螯合光环回复形成的,这表明其以高化学(> 95%)和量子产率(phi = 0.62)进行) 通过使用甲醇、乙酸、异戊二烯和三乙基硅烷进行稳态捕获实验。4a 在 23 摄氏度干燥脱氧己烷中的闪光光解导致迅速形成分配给 Ph2Ge 的瞬态(λ(最大)= 500 nm;epsilon(最大)= 1650 M(-1)cm(-1)),它以二阶动力学衰减(tau 大约 3 微米),伴随着分配给二锗烯 6a(tau 大约 40 微米;λ(最大)= 440 nm)的第二个瞬态物种的生长。从 1,1-二甲基-和 1,1-二甲基-3,4-二甲基锗环戊-3-烯(分别为 4b 和 4c)获得了类似的结果,它们提供了