8’-硝基-1-苯基-3,3-二甲基吲哚苯骈螺吡喃的光化学

Photochemistry of 8'-Nitro-1-phenyl-3, 3-dimethylindolinobenzospiropyran

标题螺吡喃(Sp)甲醇溶液直接和二苯酮敏化光发色反应的量子产率分别是0.38和0.53.2,3-丁二酮首先猝灭三线态的光发色,然后,在较高浓度时,猝灭单线态的光反应.从敏化和猝灭反应的动力学分析,计算在直接光解中的初级光物理、光化学过程的量子产率.数据表明,Sp的三线态和单线态都有光反应活性,这与反应状态相关图分析结果相一致.三线态的参数是~3τ=2.2×10^(-3) ms,κ_r=9.13×10~4s^(-1),κ_(?)=8.27×10~4 s^(-1).而且,一旦生成激发三线态,它的光化学活性大约比激发单线态大2倍.

Qnantum yields of the photocoloration of the title spiropyran for the direct and benzophenone sensitized photolyses in methanol were found to be 0.38 and 0.53, respectively. Biacetyl, at first, quenches the triplet photocoloration and then the singlet reaction inefficiently at higher concentrations. From kinetic analysis in the sensitized and quenched reactions quantitative estimation was made of the quantum yields of the primary reactions involved in the direct photolysis. The data suggest that both singlet and triplet of the title spiropyran react to form the colored form, which is in consistant with the state correlation diagram analysis. The triplet parameters are as follows: ~3τ, 2.2×10^(-3ms; k_r, 9.13×10^4 s^(-1); k_d,8.27×10~4 s^(-1) Also, the excited triplet state, once populated, is abont 2 times more efficient in the formation of fche colored form than the excited singlet state.