吡啶离子液体[BPy][BF4]与乙腈混合体系中杜醌的光化学反应动力学

用激光闪光光解方法研究了杜醌(DQ)在吡啶型离子液体N-丁基吡啶四氟硼酸盐(BPy]BF₄])与乙腈(MeCN)组成的共混溶剂中的光化学反应机理与动力学. 实验结果表明, 离子液体BPy]BF₄]对混合体系中杜醌激发三线态(³DQ^*)的瞬态吸收峰位置和吸光度大小都没有产生明显影响. 在N₂饱和条件下, 无论是在乙腈溶液中还是在BPy]BF₄]/MeCN混合溶液中³DQ^*的衰减都遵循一级反应动力学规律. 而BPy]BF₄]的存在对³DQ^*与三乙胺(TEA)之间的电子转移影响显著. 随着BPy]BF₄]/MeCN 体系中离子液体比例的增加, 杜醌三线态³DQ^*与TEA间的瞬态反应机理没有改变, 但它们之间的光诱导电子转移反应速率和生成自由基的量子产额逐渐降低, 通过改变离子液体的比例可以调节该体系中光诱导电子转移反应的速率和效率.

Photochemical Reaction Kinetics of Duroquinone in a Mixture of Ionic Liquid [BPy][BF4] and Acetonitrile

Photochemical reactions of duroquinone (DQ) in solutions consisting of mixtures of the ionic liquid N-butylpyridinium tetrafluoroborate (BPy]BF₄]) and acetonitrile (MeCN) were studied using the 355 nm laser flash photolysis technique. Increasing the ratio of BPy]BF₄] had no obvious impact on the absorption peak of the triplet excited state of DQ (³DQ^*), which followed monoexponential kinetics in the N₂-saturated solution. However, increasing the ratio of BPy] BF₄] did affect the photoinduced electron transfer process from triethylamine to ³DQ^* in the mixture by decreasing the reaction rate and the quantum yield of the transient radical. The results highlight the ability to tune the efficiency and the rate of the photoinduced electron transfer by changing the proportion of BPy]BF₄] in the mixture.