Catecholase activity of dinuclear copper(II) complexes with variable endogenous and exogenous bridge
Catecholase activity of dinuclear copper(II) complexes with variable endogenous and exogenous bridge
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DOI：
10.1016/s0020-1693(02)01106-4
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发表时间：
2002-09-26
影响因子：
2.8
通讯作者：
Mukherjee, R
中科院分区：
文献类型：
--
作者：
Mukherjee, J;Mukherjee, R
一组不同的双核铜(II)配合物家族[Cu2(L-1-O)(Mu-OH)][ClO4](2)(1)，[Cu2(L-2-O)(Mu-OH)][ClO4](2)(2)，[Cu-2(L-3-O)(mu-C3H3N2)(OClO3)(H2O)][ClO4].H2O(3)，[Cu-2(L-4)(Mu-OH)(2)][ClO4](2).H2O(4)，[Cu-2(L-5-O)(2)(OClO_3)(2)](5)和[Cu-2(bpy)(2)(mu-OH)(mu-OH2)(mu-O2CMe)][ClO4](2)(6)被用来催化3，5-二叔丁基邻苯二酚(3，5-DTBC)氧化合成3，5-二叔丁基苯二酚(3，5-DTBQ)(儿茶酚酶活性)。2，6-[N-methyl-N-(2-pyridylethyl)aminomethyl]phenol；L-2-羟基，2，6-双[N-(2-吡啶乙基)亚氨甲基]苯酚；L-3-羟基，1，3-bis[N-methyl-N-(2-pyridylethyl)amino]propan-2-ol；L-4，α，alpha‘-bis[N-(6-methyl-2-pyridylmethyl)-N-(pyrazol-1-ylmethyl)amino]-m-xylene；L-5-羟基，4-甲基-2，6-二(吡唑-1-甲基)苯酚；联吡啶；C3H3N2，吡唑根离子；H，可解离氢原子]。报道了一种新型间木基二核配体L-4的合成。利用该配体合成了一种新的二羟基桥联铜(II)配合物4，并用元素分析和物理化学方法对其进行了表征。存在的桥类型有内源性酚氧基和外源羟基(1和2)、内源烷氧基和外源吡唑酸(3)、外源羟基(4)、内源二苯氧基桥(5)和外源羟基、水和乙酸酯-(6)。除了铁磁偶联的络合物6外，所有其他的络合物都是反铁磁性偶联的，并且所有已报道的络合物都具有结构特征。用分光光度法研究了双铜(II)络合物与四氯邻苯二酚的反应，以考察在催化过程中3，5-二丁基三丁基苯与铜中心是否发生了结合(S)。进行了动力学实验，确定了反应的初始速率，其活度顺序为：1>；2远大于3>；4，远大于6(5个初始速率不能确定)。对于固定的3，5-DTBC浓度，得到了初始速率与络合物浓度的线性关系，这表明催化剂浓度是一级依赖关系。对配合物1、2、3和4进行了Michaelis-Menten动力学分析，其中配合物1是最具活性的儿茶酚酶活性催化剂。(C)2002年，爱思唯尔科学公司出版。
A group of a diverse family of dinuclear copper(II) complexes [Cu-2(L-1-O)(mu-OH)][ClO4](2) (1), [Cu-2(L-2-O)(mu-OH)][ClO4](2) (2), [Cu-2(L-3-O)(mu-C3H3N2)(OClO3)(H2O)][ClO4].H2O (3), [Cu-2(L-4)(mu-OH)(2)][ClO4](2).H2O (4), [Cu-2(L-5-O)(2)(OClO3)(2)] (5) and [Cu-2(bpy)(2)(mu-OH)(mu-OH2)(mu-O2CMe)][ClO4](2) (6) has been chosen to investigate their potential as catalysts for the aerial oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) to 3,5-di-tert-butylquinone (3,5-DTBQ) (catecholase activity) [L-1-OH, 2,6-[N-methyl-N-(2-pyridylethyl)aminomethyl]phenol; L-2-OH, 2,6-bis[N-(2-pyridylethyl)iminomethyl]phenol; L-3-OH, 1,3-bis[N-methyl-N-(2-pyridylethyl)amino]propan-2-ol; L-4, alpha,alpha'-bis[N-(6-methyl-2-pyridylmethyl)-N-(pyrazol-1-ylmethyl)amino]-m-xylene; L-5-OH, 4-methyl-2,6-bis(pyrazol-1-ylmethy)phenol; bpy, 2,2'-bipyridine; C3H3N2, pyrazolate ion; H, dissociable hydrogen atom]. The synthesis of a new m-xylyl-based dinucleating ligand L-4 is described. Using this ligand a new dihydroxy-bridged copper(II) complex 4 has been synthesised and characterised by elemental analysis and physicochemical measurements. The types of bridges present are endogenous phenoxo- and exogenous hydroxo- (1 and 2), endogenous alkoxo- and exogenous pyrazolate- (3), exogenous hydroxo(4), endogenous diphenoxo-bridge (5) and exogenous hydroxo-, aqua- and acetate- (6). Barring complex 6, which is ferromagnetically coupled, all other complexes are antiferromagnetically coupled and all reported complexes are structurally characterised. The reaction between the dicopper(II) complexes and tetrachlorocatechol was investigated spectrophotometrically to investigate whether or not, during catalysis, binding of 3,5-DTBC is occurring to the copper centre(s). Kinetic experiments have been performed to determine initial rate of reactions and the activity order follows: 1>2much greater than3>4much greater than6 (for 5 initial rate could not be determined). For a fixed 3,5-DTBC concentration, a linear relationship for the initial rates and the complex concentration is obtained, suggestive of a first-order dependence on the catalyst concentration. Analysis of Michaelis-Menten kinetic treatment has been done for complexes 1, 2, 3 and 4. Complex 1 is the most active catalyst to show catecholase activity. (C) 2002 Published by Elsevier Science B.V.