二苯酮在功能胶束中的光还原反应的研究

Study on the Photoreduction of Benzophenone Derivatives in the Functional Micelles

本文研究了一种具有分子自聚集作用的二苯酮(BP)衍生物ρ-C_6H_5COC_6H_4CH_2^+N(CH_3)_2C_(12).H_(25_·Br^-(PKT)的光还原反应及其光物理性质.连接在PKT上BP的光还原反应活性在胶束形成前后有很大差别.反应速率随着浓度增大在形成的胶束中比均相水溶液中快1.5倍.值得指出,在PKT功能胶束中的BP还原速率与普通胶束相比,增加10倍以上.动力学数据测定表明,PKT胶束大大加速了BP-三乙胺(TEA)光还原反应中的电子转移.在TEA高浓度时有利于质子转移,κ_d/κ_r值减小,κ_n/κ_(?)值增加.对不同TEA浓度的光还原机理亦作了讨论.

Photoreduction of benzophenone (BP) derivatives characteristic of molecular selfaggregation (PKT) [p-C_6H_5COC_6H_4CH_2 N^+(CH_3)_2C_(12)H_(25)Br^-] and its physical behaviors have been studied. The results obtained indicate that the photorednction activity of benzophenone linked to PKT by amine (TEA) is different singnificantly before and after formation of PKT micelle and reaction rate-enhancement with increasing concentration in the mioelles formed is about 1.5 times greater than that in the homogeneons aqueous solution. It is worthy of note that the photoreduction rate of benzophenone increases by above 10 folds in PKT functional micelles compared with Teaction in conventional micelles. Kinetic data show that the electron transfer process in the BP/TEA photoreduction is promoted significantly by PKT micelles and the proton transfer process becomes more efficient at high amine conoentration, leading to a decrease of k_d/k_r and an increase of k_n/k_e. The photoreduction mechanism of BP bound to PKT under different conditions were discussed.