New Oxygen Activation Reaction with Rationally Designed Metal Complexes

合理设计金属配合物的新型氧活化反应

基本信息

批准号：
11228207
负责人：
NARUTA Yoshinori
金额：
$ 38.14万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2002
项目状态：
已结题

项目摘要

The aim of this research is the elucidation of the reaction mechanism working in two enzymes, which play the interconversion between dioxygen and water, respectively. The detailed reaction mechanism for the four-electron reduction of cytochrome c oxidase has not clarified yet, but the role(s)of the each component around the active site is not fully understood. We obtained two major results on these account s with chemical models.1.The oxygenation of the reduced form of N_4Cu complex-tethered heme gave a stable peroxo complex. Its crystal structure was successfully disclosed to show that O_2 bound in a 'side-on' fashion to fom μ-η^2:η^1 structure. This gives a very substantial standpoint to discuss the chemistry of heterodinuclear complexes.2.We prepared CcO active site models, which have a tyrosine-cross linked imidazolate as the part of Cu_B ligand. The correponding peroxide complex showed the different decomposition pathway to give heme Fe(III)-OH/Cu(II). Thus, the phenolic hydroxyl group plays an important role in the reaction of the O_2 complex.Water oxidation is the key reaction to sustain life on the earth. We accomplished stoichiometric oxidation of Mn(III)porphyrin dimer, which has established to catalyze water oxidation under cathodic conditions. Upon oxidation with a peracid, the conesponding Mn(V)-O complex was generated in a good stability and was assigned its structure by spectroscopic methods. This is the first example of Mn(V)=O complex, which is well characterized. By the addition of an acid to the solution of Mn(V)=O spontaneously evolved O_2 in almost quantitative yield. Thus, we succeded to prove that [Mn(V)=O]_2 oxidizes water.

这项研究的目的是阐明在两种酶中起作用的反应机制，分别在二氧化物和水之间起着相互转换。细胞色素C氧化酶的四电子还原的详细反应机制尚未阐明，但是尚未完全了解活性位点周围每个成分的作用。我们通过化学模型获得了两个主要结果。1。n_4cu复合体血红素的还原形式的氧合产生了稳定的过氧络合物。它的晶体结构已成功披露，以表明O_2以“侧面”方式结合到FOMμ-η^2：η^1结构。这给出了讨论异源核复合物的化学的非常实质性的立场。2。我们准备了CCO活性位点模型，该模型具有酪氨酸 - 杂交连接的咪唑酸酯作为CU_B配体的一部分。克雷蛋白的过氧化物复合物显示出不同的分解途径，以给出血红素Fe（iii）-OH/Cu（ii）。这就是酚羟基在O_2复合物的反应中起重要作用。水氧化是维持地球生命的关键反应。我们完成了Mn（III）卟啉二聚体的化学计量氧化，该二聚体已建立以在阴极条件下催化水氧化。用peracid氧化后，对应的Mn（V）-O复合物以良好的稳定性产生，并通过光谱方法分配其结构。这是Mn（V）= O复合物的第一个例子，它的表征很好。通过将酸添加到Mn（V）= O的溶液中，以几乎定量的产量自发演变。那就成功证明了[Mn（v）= O] _2氧化水。