1,4,7,10-Tetraazacyclododecane Metal Complexes as Potent Promoters of Carboxyester Hydrolysis under Physiological Conditions
作者:Michael Subat、Kristina Woinaroschy、Stefan Anthofer、Barbara Malterer、Burkhard König
DOI:10.1021/ic070101z
日期:2007.5.1
the two metal ions (the average distance of Zn-O- = 1.9 A). The distance between the Zn(II) ion and the fourth N atom is 2.6 A. All Zn(II) complexes promote the hydrolysis of 4-nitrophenyl acetate (NA) under physiological conditions, while those of Cu(II) and Ni(II) do not have a significant effect on the hydrolysis reaction. The kinetic studies in buffered solutions (0.05 M Tris, HEPES, or CHES, I =
具有不同长度(二吡啶和三吡啶)的不同杂环间隔基(三嗪和吡啶)或氮杂皇冠(Azacrown)侧基及其单核和双核Zn(II)的新的1,4,7,10-四氮杂十二烷([12] aneN4或循环素)配体),Cu(II)和Ni(II)配合物已被合成和表征。通过电位pH滴定法测定与配位的金属离子配位的水分子的pKa值,其变化范围为7.7至11.2,具体取决于金属离子和配体的性质。[Zn2L2] mu-OH(ClO4)3.CH3CN.H2O的X射线结构显示每个Zn(II)离子呈四面体几何结构,并与三个环原子的N原子结合(Zn-N的平均距离= 2.1 A ),并且在顶端位置具有连接两个金属离子的mu-OH桥(Zn-O-的平均距离= 1.9 A)。Zn(II)离子与第四个N原子之间的距离为2.6A。所有的Zn(II)配合物在生理条件下均能促进乙酸4-硝基苯酯(NA)的水解,而Cu(II)和Ni(II)的那些对