光诱导下卟啉蒽醌化合物分子内电子转移过程的研究(Ⅱ)──顺磁共振法

A Study of Intramolecular Electron Transfer Process of Porphyrin-anthraquinone Under Photoinduction(Ⅱ)─Paramagnetic Resonance Method

用ESR研究了几种新型叶啉蒽醌化合物低温下光诱导产生分子内电子转移产物P+－AQ-自由基对．对比研究了不同卟啉配体、金属卟啉、有机碱轴向配位和溶剂对电子转移的影响．

In this paper, the method of paramagnetic resonance was used to study the pro-cess of formation of ionic free radicals of a new type of porphyrin-anthraquinone compounds through intramolecular electron transfer under photoinduction at a low temperature and the effects of different porphyrin ligands, metal-porphyrin, organic bases axial coordination and solvents on the electron transfer were studied. The experimental results indicate that ESR signal intensities of porphyrin and metal-porphyrin were increased with time and tend to be stable after 50 min. The signal intensities of PAQ are in the order:H2TDMAPPQ>H2(o-NH)PTriPPQ>H2(p-NH)PPQ, while signal intensity of ZnPAQ is greater than that of the corresponding PAQ. The formation rate and quantum yield of ionic free group pair P+·-AQ-· for PAQ and ZnPAQ in the strong polar solvent(DMF) are lower than those in weak polar solvent(CH2Cl2). The axial coordination with piperidine and imidazole increased ESR signal intensity of ZnTDMAPPQ, which played a promoting role for the charge separation ofZnPAQ. Furthermore, β-carotene may further enhance the charge separation of ZnTDMAP-PQ with positively charged side chain. Therefore, this kind of PAQ compounds are ideal ones for photosynthesis.