摘要
在２５±０．１℃，Ｉ＝０．１ｍｏｌ·ｄｍ－３ＫＮＯ３条件下，采用ｐＨ电位滴定法，测定了新型配体，Ｎ，Ｎ′－二－（２′－羟基）苄基－乙二胺（ＢＥＤＡ）和Ｎ，Ｎ′－二－（２′－羟基）苄基－二乙烯基三胺（ＢＤＴＡ）的质子化常数以及它们与Ｃｕ（Ⅱ）离子的配位平衡常数，并进一步求得了配合物Ｃｕ－ＢＥＤＡ和Ｃｕ－ＢＤＴＡ中酚羟基的离解常数ｐＫａ值。通过分光光度法，在２５±０．１℃，Ｉ＝０．１ｍｏｌ·ｄｍ－３ＫＮＯ３，ｐＨ＝７～９（５０ｍｍｏｌ·ｄｍ－３缓冲溶液）条件下，得到了配体的Ｃｕ（Ⅱ）配合物催化对－硝基苯酚乙酸酯（ＮＡ）水解的的催化速率常数ｋＮＰ［（ｍｏｌ·ｄｍ－３）－１·ｓ－１］，结果表明这类配合物可以用作金属水解酶的模拟物，由催化机理出发对实验结果进行了解释。
The coordination of Cu(Ⅱ) with ligands N, N′ (2 hydroxylbenzyl) ethylenediamine (BEDA) and N, N′ (2 hydroxybenzyl) diethylenetriamine (BDTA) has been investigated by pH titration at 25±0 1℃, and I =0 1 mol·dm -3 (KNO 3), from which the deprotonation constanst of the phenols in the ligands coordinated with Cu(Ⅱ) were obtained Furthermore, 4 nitrophenyl acetate (NA) hydrolysis catalyzed by the Cu(Ⅱ) complexes of these ligands in 10% ( V/V ) CH 3CN, at 25±0 1℃, I =0 1 mol·dm -3 (KNO 3) and pH range 7￣9(50 mmol·dm -3 buffers), has been carried out and the second order rate constants ( k NP ) of the reactions were obtained spectrophotometrically The experimental results indicate that these Cu(Ⅱ) complexes can be used as models of metallohydrolases with participation of two kinds of nucleophiles, i e Cu(Ⅱ) bound -OAr and Cu(Ⅱ) bound -OH
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
1999年第2期165-172,共8页
Chinese Journal of Inorganic Chemistry
基金
国家教委博士点基金
国家自然科学基金
