卟啉酞菁模型化合物光致电子转移研究

Study on the Intramolecular Electron Transfer of TTP-(CH_2)n-Pc

本文采用时间相关单光子计数对卟啉酞菁TTP－（CH2）n－PC模型化合物的光致电子转移进行了研究．发现激发PC时，呈现单指数衰减，n＝4时电子转移速率最快，激发TTP时呈现双指数衰减，表明除能量转移外，同时存在电子转移，随n的增大电子转移速率减小，活化能、重排能增加；电子转移效率下降，电子转移反应△GCS与电荷分离活化络合物衰变速率kCT，按以下规律：其倒置可按Marcus理论中重排能啬使活化能增加得以解释。

The intramolecular electron transfer of TTP-(CH2)n-Pc was studied by means of time correlated single-photon counting method. When the Pc subunit of the com pound is excited, the fluorescence of the compound is quenched by intramolecular electron transfer and the electron transfer is most favorable in the compound with n=4. When the TTP subunit of the compound is excited, the fluorescence decay of the compound will be biexponential, which shows the existence of an electron transfer process. Some kinetic parameters were derived from the experimental data. With n increasing, the acti vation energy and the reorganization energy increases whereas the electron transfer rate decreases. Moreover, the free enthalpy change of electron transfer reaction △GCS and the charge-separated rate kCS are in the order of: The difference between the order of △GCS and of electron transfer rate can be interpreted according to Marcus theory.