Structural and catalytic characterization of a heterovalent Mn(II)Mn(III) complex that mimics purple acid phosphatases.
Structural and catalytic characterization of a heterovalent Mn(II)Mn(III) complex that mimics purple acid phosphatases.
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DOI：
10.1021/ic9005086
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发表时间：
2009-11
影响因子：
4.6
通讯作者：
S. Smith;M. Riley;C. Noble;G. Hanson;R. Stranger;V. Jayaratne;Germán Cavigliasso;G. Schenk;L. Gahan
中科院分区：
文献类型：
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作者：
S. Smith;M. Riley;C. Noble;G. Hanson;R. Stranger;V. Jayaratne;Germán Cavigliasso;G. Schenk;L. Gahan
制备了双核杂价锰模型配合物[Mn(II)Mn(III)(L1)(OAc)(2)] ClO(4) × H(2)O （H（2)L1 = 2-（（3-（（双（吡啶-2-基甲基）氨基）甲基）-2-羟基-5-甲基苄基）（吡啶-2-基甲基）氨基）甲基）苯酚），并对其进行了结构、光谱和计算研究。该配合物的磁性和电子性质与其结构有关。配合物是弱反铁磁耦合的(J约为-5 cm(-1), H = - 2js (1) x S(2))，电子顺磁共振（EPR）和磁圆二色性（MCD）光谱表明Mn（III）中心的Jahn-Teller畸变主要是四方压缩，有显著的菱形成分。利用密度泛函理论进行的电子结构计算证实了实验研究得出的结论。与同结构的M(II)Fe（III）配合物（M = Fe, Mn, Zn, Ni）相比，Mn(II)Mn（III）体系具有双功能，具有过氧化氢酶和水解酶活性，并且仅检测到一个催化相关的pK(a)（= 8.2）。本文还讨论了其中的机械含义。
The binuclear heterovalent manganese model complex [Mn(II)Mn(III)(L1)(OAc)(2)] ClO(4) x H(2)O (H(2)L1 = 2-(((3-((bis(pyridin-2-ylmethyl)amino)methyl)-2-hydroxy-5-methylbenzyl)(pyridin-2-ylmethyl)amino)-methyl)phenol) has been prepared and studied structurally, spectroscopically, and computationally. The magnetic and electronic properties of the complex have been related to its structure. The complex is weakly antiferromagnetically coupled (J approximately -5 cm(-1), H = -2J S(1) x S(2)) and the electron paramagnetic resonance (EPR) and magnetic circular dichroism (MCD) spectra identify the Jahn-Teller distortion of the Mn(III) center as predominantly a tetragonal compression, with a significant rhombic component. Electronic structure calculations using density functional theory have confirmed the conclusions derived from the experimental investigations. In contrast to isostructural M(II)Fe(III) complexes (M = Fe, Mn, Zn, Ni), the Mn(II)Mn(III) system is bifunctional possessing both catalase and hydrolase activities, and only one catalytically relevant pK(a) (= 8.2) is detected. Mechanistic implications are discussed.