Photochemical detection of intramolecular energy transfer between nonconjugated chromophores in rigid model compounds
作者:Julian M. Menter、Nicolae Filipescu
DOI:10.1039/j29700000464
日期:——
only by the tetralindione chromophore led to rearrangement of the fluorenespirocyclopropane system to dibenzofulvene. The photorearrangement of the ‘isolated’ acceptor chromophore, the tricyclo[3,2,1,02,4]-octane-3-spiro-9′-fluorene (V), to 2-(fluornen-9-ylidene)bicyclo[2,2,1]heptane was studied separately by direct and sensitized excitation. The photochemical quantum yield of the intramoleculary sensitized
4,5- benzotetracyclo [6,3,1,0照射2,7,0 9,11 ]十二烷-10-螺9'-芴-3,6-二酮(III)与光吸收仅由四氢萘二酮生色团导致芴螺环丙烷系统重排成二苯并富勒烯。“分离的”受体发色团,三环[3,2,1,0 2,4 ]-辛烷-3-螺-9'-芴(V)的光重排成2-(芴-9-亚烷基)双环[2,2,1]庚烷分别通过直接和敏化激发进行研究。(III)中分子内敏化反应的光化学量子产率与(V)的分子内敏化光异构化的光化学量子产率相当。这与从n,π进行有效的能量转移是一致的*在模型化合物(III)中,将酮的三重态降低到最低的π,π *在芴中的三重态。芴螺环丙烷系统非常适合用作模型化合物的受体,其非共轭的供体和受体生色团不易弯曲地连接至同一分子框架。这些化合物中的能量转移效率可以根据供体的选择性激发时受体重排的程度进行定量评估。讨论了光异构化的机理。