摘要
用分光光度法研究了两种不对称Salen-Mn(Ⅲ)配合物催化α-吡啶甲酸对硝基苯酚酯(PNPP)的水解动力学.提出了相应的PNPP催化水解机理,讨论了底物浓度、体系的酸碱度、温度以及配合物结构对PNPP催化水解反应的影响.结果表明:此两种Schiff碱锰(Ⅲ)配合物在催化PNPP水解中均表现出较好的催化活性,PNPP水解速率随着底物浓度、体系pH值的增大而增大;在15～55℃温度范围内,未观察到催化剂失活现象;其中,带有苯并氮杂-15-冠-5侧基的不对称Salen-Mn(Ⅲ)配合物比带有吗啉基的另一配合物拥有更高的催化活性,这可能主要由这两种模拟水解酶之间较大的疏水微环境差异所引起.
The hydrolysis kinetics of p-nitrophenol picolinate （PNPP） induced by two kinds of unsymmetrical Salen-Mn（Ⅲ） complexes have been investigated under a series of conditions. The mechanism of PNPP catalytic hydrolysis has been proposed. Effects of acidity, temperature and structure of catalyst on the hydrolytic rate of PNPP have been discussed. The observations reveal that both complexes exhibit better catalytic activity, and the hydrolytic rate of PNPP increases with the increasing pH and temperature values. In the range of 15 - 55 ℃, the deactivation of catalysts has not been observed. In addition, the one complex containing benzoaza-15-crown-5 pendant has a relatively higher catalytic activity over another one containing morpholine, which may be due to the preponderant effect of hydrophobic environment of the former.
出处
《分子催化》
EI
CAS
CSCD
北大核心
2007年第6期572-578,共7页
Journal of Molecular Catalysis(China)
基金
国家自然科学基金(No.20072025
20173038)
四川省教育厅重点基金项目(No.2005D007).
