杜醌自由基光化学路径的CIDEP研究

用自制的高时间分辨电子自旋共振波谱仪,测量得到了酸性、碱性和胶束环境下的光解杜醌/乙二醇(DQ/EG)溶液瞬态自由基的化学诱导动态电子自旋极化(CIDEP)谱.在光解均相DQ/EG溶液时,观察到了以增强发射的的中性杜半醌自由基(DQH.)的CIDEP信号;在碱性环境下(pH=9)和TX-100胶束环境下光解DQ/EG体系时得到杜醌负离子自由基(DQ-.)的CIDEP信号;在酸性环境下(pH=2.5)光解DQ/EG体系时,出现的又是中性杜半醌自由基(DQH.)的CIDEP信号.实验结果显示,DQH.由3DQ*与EG之间的氢原子转移反应生成,DQ.-由DQH.的去质子化反应生成,反应中伴随着极化转移.

A CIDEP study on the photochemical route of duroquinone radicals

The CIDEP spectra of the transient radicals in the photolysis of duroquinone(DQ)/ ethylene glycol(EG) system in acid, basic and micellar environment were measured with the homemade highly time-resolved ESR spectrometer. In the DQ/EG homogeneous solution, the enhanced emissive CIDEP signal of the neutral durosemiquinone radical DQH· was observed. When the DQ/EG solution with pH=9 or DQ/EG/TX-100/H2O micelle system was photolyzed, the CIDEP signal of the duroquinone anion radical (DQ·-) was obtained. When the DQ/EG solution with pH=2.5 was irradiated, the CIDEP signal of DQH· appeared. These experimental results indicate that the neutral radical DQH· was formed through the proton transfer from EG to 3DQ* and DQ·- was formed from the dissociation of DQH· accompanying polarization transfer.