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本文研究了各种金属酞菁以及带有不同取代基的锌酞菁敏化光还原硝基化合物的反应。确定了光敏还原反应的主要产物是氨基和羟氨基化合物;羟氨基化合物与亚硝基化合物通过暗反应缩合生成偶氮N-氧化物。测定了它们的氧化还原电位和荧光量子产率。从敏化光还原反应的量子产率及荧光猝灭与硝基化合物浓度的依赖关系,计算出各种金属酞菁激发单重态与三重态的敏化效率。受激发金属酞菁将电子转移至硝基化合物是敏化光还原反应的起始过程。电子转移生成离子自由基对后,电荷分离与逆电子转移过程相互竞争。由于自旋选择规则的限制,激发三重态的敏化效率一般比激发单重态的敏化效率高。为了提高敏化光还原反应的效率,除选择三重态产率较高的敏化剂外,改变敏化剂的结构可提高敏化剂激发单重态的敏化效率,从而提高敏化光还原反应的量子产率.
In this paper, the reactions of various metal phthalocyanines and zinc phthalocyanine sensitized photoconductive nitro compounds with different substituents were studied. The main products of photoreduction were identified as amino and hydroxyamino compounds. Hydroxyamino compounds and nitroso compounds were condensed to form azo-N-oxides by dark reaction. Their redox potential and fluorescence quantum yield were determined. Based on the quantum yield of sensitized photoreduction reaction and the dependence of fluorescence quenching on the concentration of nitro compound, the sensitization efficiencies of singlet and triplet excited by various metal phthalocyanines were calculated. The excited metal phthalocyanine electron transfer to the nitro compound is the initial process of sensitized photoreduction. After the electron transfer generates the ion radical pair, the charge separation and the counter electron transfer process compete with each other. Due to the limitation of the spin selection rule, the sensitization efficiency of the excited triplet state is generally higher than the sensitization efficiency of the excited singlet state. In order to improve the efficiency of sensitized photoreduction, in addition to selecting sensitizers with higher triplet yields, changing the structure of the sensitizers can increase the sensitization efficiency of the singlet excited by the sensitizers and thus enhance the sensitized light reduction The quantum yield of the reaction.