卟啉-酞菁分子内能量传递和电子转移的溶剂效应

The Solvents Effects on Intramolecular Energy and Electron Transfer of Porphyrin-phthalocyanine Heterodimers

用稳态荧光光谱研究了以氧原子和哌嗪作为连接基的卟啉酞菁二元分子在不同溶剂中的分子内能量传递和电子转移过程结果表明;分子内的能量传递和电子转移是两个相互竞争的过程，在非极性溶剂中，激发单重态的能量传递是主要过程，而在极性溶剂中则以电子转移为主运用Rehm-Weller公式计算了两种二元化合物在不同溶剂中的电子转移反应的自由能变化△G0ET，表明溶剂的极性对电子转移反应的自由能变化△G0ET影响很大极性越大;体系中的电子转移反应的△G0ET、越负，电子转移反应越易进行由于电子转移过程较能量传递过程进行得快，所以表现为体系中能量传递效率降低而电子转移效率增大。

Intraxnolecular energy transfer and electron transfer of porphyrin-phthalocyanine heterodimers, linked by oxygen atom or piperazine in different solvents were investigated by fluorescence spectroscopy. The energy transfer and electron transfer efficiency were calculated. It has been found that energy transfer occurred in competition with electron transfer process depending on the polarity of the s01vents. In polar solvents, electron transfer prevails while the energy transfer is favored in nonpolar solvents. The driving force()of the electron transfer reaction in different solvents was estimated using Rehm-Weller equation. The results indicated that the conformations of the heterodimers as well as the ability of the solvent to stablize tlie charge-seperated state affect the photophysical process greatly. Good correlations of and ET with solvent polarity f have been obtained.