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水氧化反应中过氧中间体钌(iv)侧的分离
作者:小柯机器人 发布时间:2021/6/2 16:00:17

西班牙加泰罗尼亚化学研究学院Julio Lloret-Fillol报道了水氧化反应中过氧中间体钌(iv)侧的分离。相关研究成果于2021年5月31日发表在《自然—化学》。

在光合作用过程中,自然界用来减少二氧化碳的电子来自于光系统II的析氧复合体中的水氧化。分子催化剂已经成为理解其机理的模型,特别是O–O键形成反应,目前还没有完全了解。

该文中,研究人员报告了一个钌(IV)侧的过氧络合物,其作为在速率决定的O–O键形成步骤后形成的物种的“缺失环节”。过氧化络合物的Ru(IV)侧(η2-1IV–OO)是在过量氧化剂存在下由分离的钌(IV)氧络合物(1IV=O)生成的。通过实验和理论研究相结合的方法确定了η2-1IV–OO的原子氧化态(Ⅳ)和自旋态(单线态)18O-和2H-标记研究发现,在形成η2-1IV–OO时,通过H2O分子对高亲电性金属-oxo物种的亲核攻击,证明了O2的直接演化过程

该研究表明,水亲核攻击是O–O键形成的一种可行机制,正如先前基于间接证据提出的那样。

附:英文原文

Title: Isolation of a Ru( iv ) side-on peroxo intermediate in the water oxidation reaction

Author: Carla Casadevall, Vlad Martin-Diaconescu, Wesley R. Browne, Sergio Fernndez, Federico Franco, Noem Cabello, Jordi Benet-Buchholz, Benedikt Lassalle-Kaiser, Julio Lloret-Fillol

Issue&Volume: 2021-05-31

Abstract: The electrons that nature uses to reduce CO2 during photosynthesis come from water oxidation at the oxygen-evolving complex of photosystem II. Molecular catalysts have served as models to understand its mechanism, in particular the O–O bond-forming reaction, which is still not fully understood. Here we report a Ru(IV) side-on peroxo complex that serves as a ‘missing link’ for the species that form after the rate-determining O–O bond-forming step. The Ru(IV) side-on peroxo complex (η2-1IV–OO) is generated from the isolated Ru(IV) oxo complex (1IV=O) in the presence of an excess of oxidant. The oxidation (IV) and spin state (singlet) of η2-1IV–OO were determined by a combination of experimental and theoretical studies. 18O- and 2H-labelling studies evidence the direct evolution of O2 through the nucleophilic attack of a H2O molecule on the highly electrophilic metal–oxo species via the formation of η2-1IV–OO. These studies demonstrate water nucleophilic attack as a viable mechanism for O–O bond formation, as previously proposed based on indirect evidence.

DOI: 10.1038/s41557-021-00702-5

Source: https://www.nature.com/articles/s41557-021-00702-5

 

期刊信息

Nature Chemistry:《自然—化学》,创刊于2009年。隶属于施普林格·自然出版集团,最新IF:21.687
官方网址:https://www.nature.com/nchem/
投稿链接:https://mts-nchem.nature.com/cgi-bin/main.plex