关于氧化锌/双吡啶高氯酸盐非均相光诱导电子转移过程的研究

STUDIES ON THE PHOTOINDUCED ELECTRON TRANSFER PROCESSES IN ZINC OXIDE/PARAQUATS HETEROGENEOUS SYSTEMS

用ESR方法对9种不同双吡啶高氯酸盐与氧化锌组成的非均相体系的光诱导电子转移过程进行了系统的研究。ZnO-PQ^(++)-胶束-苯的分散系,经350nm～420nm的紫外光照后,PQ^(++)被还原成PQ^+。具有大共轭结构的PQ^+的ESR信号较强。胶束的存在也可使ESR信号增强。当体系充氧时,PQ^+信号消失,并有超氧阴离子基O_2^-和羟基·OH被检出。

The photoinduced electron transfer processes between zinc oxide and 9 kinds of Paraquats have been studied systematically by means of ESR. The dispersion system of ZnO-Paraquat-Micelle-benzene could give strong ESR signals after being irradiated by UV light, it means that photoinduced electron transfer processes between ZnO solid and Paraquat molecules took place without doubt, and PQ++ were reduced to form PQ+ radicals. The results also show that the PQ+ radicals with conjugation structure might give stronger ESR signals than those without conjugation structure; Micelle could also increase the strength of ESR signals; As oxygen was present in the system , ESR signals of PQ+ radicals disappeared, but spin adducts [DMPO-O2-]· and [DMPO-OH]· were detected. It is sure that the photoinduced electron transfer processes between ZnO and Paraquats can be seriously obstructed by oxygen. Zinc oxide ; Photoinduced electron transfer ; DMPO ; Paraquat ; ESR .