Photoinduced Electron-Transfer Reactions of Polyenes and Small Ring Compounds

从能面角度研究了2,5-二烷基-1,5-己二烯衍生物的光诱导CR - Cope重排。结合化学证据、二烯阳离子自由基环化的Ea结果以及脉冲辐射分解和光声量热分析得到的环己-1,4-阳离子自由基离子对能级，建立了光诱导CR - Cope重排的阳离子自由基环化-双自由基裂解机制。与CR Cope重排有关的1,4-二芳基-2,3-二甲基双环[2.2.0]己烷的PET反应提供了1,4-二芳基-2,3-二甲基双环[2.2.0]己烷阳离子自由基的增敏剂和溶剂极性依赖的双反应性。2,6-二芳基-1,6-庚二烯阳离子自由基在分子内[2+2]环加成生成双环[3.2.0]己烷是有效的，但随着两个乙烯基之间亚甲基数目的增加，其效率显著降低。采用激光闪光光解法研究了3,4-二（苯乙烯）取代呋喃和吡咯衍生物的PET反应，证实了二亚甲基呋喃和二亚甲基吡咯衍生物的熔融生成，并提供了与缺电子亲疏试剂化学俘获的速率常数。结合立体化学捕获和MO计算，确定了二甲基呋喃和二甲基吡咯衍生物的基态单重态。本文研究了含吸电子基团的吡咯衍生物的自旋多重性反转。BTDA和三种二乙烯基苯的固态分子配合物的光激发反应通过电子转移提供了有趣的[2+2]环加成反应。本文研究了BTDA与二乙烯基苯分子配合物的固态PET反应中单晶到单晶转化的绝对不对称合成。少

The photoinduced CR Cope rearrangements of 2,5-diaryl-1,5-hexadiene derivatives were investigated in terms of the energy surface. Combining chemical evidences with results on Ea for cyclization of diene cation radicals and the energy level of the cyclohexa-1,4-cation radical ion-pair obtained by pulse-radiolysis and photoacoustic calorimetric analysis, a cation radical cyclization-diradical cleavage mechanism was established for the photoinduced CR Cope rearrangement. The PET reaction of 1,4-diaryl-2,3-dimethylbicyclo[2.2.0]hexanes which is related to the CR Cope rearrangement provided the sensitizer and solvent polarity-dependent dual reactivity of 1,4-diaryl-2,3-dimethylbicyclo[2.2.0]hexane cation radicals. The intramolecular [2+2]cycloadditions of 2,6-diaryl-1,6-heptadiene cation radicals to form bicyclo[3.2.0]hexanes occurred efficiently, but the efficiency markedly decreased with an increase in the number of the methylene group between two stirene units for the PET reactions of 2, … More 7-diaryl-1,7-octadienes and 2,8-diaryl-1,8-nonadienes.The PET reactions of the 3,4-bis(styryl)-substituted furan and pyrrole derivatives were investigated by laser flash photolysis, which proved the generation of fused dimethylenefuran and dimethylenepyrrole derivatives and provided rate constants of chemical capture with electron-deficient diylophiles. By combination of these results with stereochemistry of chemical capture and MO calcultations, the ground state singlet states of fused dimethylenefuran and dimethylenepyrrole derivatives was determined. Experimental verification of the inversion of the spin multiplicity of dimethylenepyrroles is currently investigated for pyrrole derivatives with an electron-withdrawing group.Photoexciation reactions of solid state molecular complexes of BTDA and three divinyl benzenes provided intersting [2+2]cycloaddition reactions via electron-transfer. The probable absolute asymmetric synthesis via the single crystal-to-single crystal transformation is currently investigated for the solid state PET reaction of the molecular complex of BTDA and omicron-divinylbenzene. Less