单重态氧化学VIII.类卟啉稀土配合物光敏化产生单重态氧的ESR研究

用电子自旋共振(ESR)方法研究类卟啉稀土配合物(CO2H-APPC)Gd]Cl2)光敏产生单重态氧的II型机制。利用2,2, 6, 6-四甲基哌啶(TEMP)对单重态氧的捕捉, 测定所生成的氮氧自由基的ESR信号, 经加NaN3和CD3OD的实验, 证实了(CO2H-APPC)Gd]Cl2)光敏作用可有效地产生单重态氧, 并观察到在实验所用的浓度范围内, 随着光敏剂浓度加大, 生成的单重态氧也增加, 同时比较了几种不同稀土离子配合物产生单重态氧的差别。结合氧的消耗和氮氧自由基的ESR线宽变化对氧浓度的依赖性, 证明了类卟啉稀土配合物光敏化生成单态氧的II型反应在光动力光疗中起关键作用。

Chemistry of singlet oxygen VIII. ESR studies of singlet oxygen generated by photosensitization of porphyrin-like rare earth complexes

Porphyrin-like rare earth metal complexes (CO2H-APPC)Gd]Cl2) are a kind of promising PDT agents due to their very long absorption wavelength at near IR region (770nm). In this paper, the generation of singlet oxygen during photoirradiation of porphyrin-like rare earth metal complexes was detected by the formation of 2, 2, 6, 6-tetramethylpiperidine-N-oxide radical (TEMPO) using ESR spectroscopic techniques. Sodium azide diminished the ESR signal intensity, whereas deuterated solvents augmented the ESR signal intensity. The rate of production of singlet oxygen was dependent not only upon the concentration of (R-APPC)RE]Cl2 and the time of irradiation but also on the oxygen content of the reaction mixture. Different central metal ions and different substituents affected the rate of generation of singlet oxygen dramatically.