冠醚化Schiff碱配合物金属胶束催化BNPP水解动力学  

Kinetics of BNPP Hydrolysis Catalyzed by the Metallomicelle Based on Crown Schiff Base Complex

作　　者：张进[1] 唐英[1] 谢家庆[2] 李建章[3] 曾宪诚[3] 胡常伟[3] 

机构地区：[1]渝西学院化学系,重庆402168 [2]重庆工学院生物工程学院,重庆400050 [3]四川大学化学学院,绿色化学与技术教育部重点实验室,成都610064

出　　处：《物理化学学报》2005年第4期408-413,共6页Acta Physico-Chimica Sinica

基　　金：高等学校优秀青年教师教学科研奖励计划资助项目~~

摘　　要：研究了两种新的冠醚化Schiff碱过渡金属配合物与表面活性剂Brij35(聚氧乙烯(23)十二烷基醚)形成的金属胶束对BNPP(对硝基苯酚磷酸二酯)的催化水解反应.探讨了催化反应机理,建立了一种金属胶束催化BNPP水解的动力学数学模型;计算了模拟酶催化反应的相关参数和表观活化能.结果表明,此类金属胶束作为模拟水解金属酶对BNPP水解反应表现出良好的催化活性.The metallomicelle made from surfactant micelle and new crown Schiff base magnesium (III) and cobalt(II) complexes were used for bis(4-nitrophenyl) phosphate(BNPP) catalytic hydrolysis. Kinetic studies were carried out by UV-Vis methods with a GBC 916 UV-Vis spectrophotometer equipped with a thermostatic cell holder. The pseudo first order rate constants(k(obs)) of BNPP hydrolysis were obtained based on the initial rate method by monitoring the release of p-nitrophenol at 400 nm, and the substrate to catalyst concentration ratio was in more than 10-fold excess. The change of ultraviolet characteristic spectra of the reactive systems was analyzed. According to the results of the characteristic spectra analysis in the reaction system, a comparison of the hydrolytic rate of NPP with that of BNPP under same reaction condition, and the pH-dependence of BNPP hydrolysis rate, a mechanism involving transition metal-hydroxide species of the catalytic hydrolysis was proposed. A kinetic mathematical model of BNPP cleavage catalyzed by the metallomicelle was found. The results indicate that the metallomicelle used as mimetic hydrolase in BNPP hydrolysis exhibits efficient catalytic performance. The pseudo-first-order rate constants of BNPP hydrolysis catalyzed by the metallomicelle is 3.05x106 times more than that of spontaneous hydrolysis of BNPP. The catalytic activity of metallomicelle is the highest under pH 8.5 and at 318 K in the solution. The apparent active energy and the preexponential factor for the catalytic reaction were calculated to be 17.5 kJ . mol(-1) and 6.02 x 10(-2) s(-1) for MnL2Cl, and 17.6 kJ . mol(-1) and 5.39x10(-2) s(-1) for CoL2, respectively. The final products of the titled reaction are found to be p-nitrophenol and H3PO4.

关 键 词：金属胶束酶模型 BNPP催化水解 动力学 

分 类 号：O643.3[理学—物理化学]