美国加利福尼亚大学伯克利分校Jonathan Rittle团队报道了预组织三铁簇中O₂的晶体断裂。相关研究成果发表在2024年12月24日出版的《美国化学会杂志》。

在自然界中，氧气的四电子还原是在预组织的多金属活性位点催化的。这些复杂的活性位点通常具有低配位、氧化还原活性金属中心的精确定位，以促进快速的O₂活化过程，从而避免产生有毒的、部分还原的氧物种。很少有仿生结构同时重现这些生物辅因子的复杂性和反应性。

该文中，研究人员报告了由磷酰亚胺配体模板化的三铁（II）活性位点的固态O₂活化。通过晶体内O₂剂量实验以及光谱、结构、磁性和计算研究，对O₂还原中间体的结构进行了深入研究。这些数据表明在暴露于O₂时原位形成Fe₂^IIIFe^IV二氧代中间体，该中间体参与与外源底物的氧原子和氢原子转移反应，以提供稳定的Fe^IIFe^XIII氧物种。

该研究为了解复杂多金属活性位点上键形成和断裂过程的动力学，提供了非同寻常的细节。

附：英文原文

Title: In Crystallo O2 Cleavage at a Preorganized Triiron Cluster

Author: Heui Beom Lee, Nicholas Ciolkowski, Mackenzie Field, David A. Marchiori, R. David Britt, Michael T. Green, Jonathan Rittle

Issue&Volume: December 24, 2024

Abstract: In Nature, the four-electron reduction of O2 is catalyzed at preorganized multimetallic active sites. These complex active sites often feature low-coordinate, redox-active metal centers precisely positioned to facilitate rapid O2 activation processes that obviate the generation of toxic, partially reduced oxygen species. Very few biomimetic constructs simultaneously recapitulate the complexity and reactivity of these biological cofactors. Herein, we report solid-state O2 activation at a triiron(II) active site templated by phosphinimide ligands. Insight into the structure of the O2 reduction intermediates was obtained via in crystallo O2 dosing experiments in conjunction with spectroscopic, structural, magnetic, and computational studies. These data support the in situ formation of an Fe2IIIFeIV-dioxo intermediate upon exposure to O2 that participates in oxygen atom and hydrogen atom transfer reactivity with exogenous substrates to furnish a stable FeIIFe2III-oxo species. Combined, these studies provide an extraordinary level of detail into the dynamics of bond-forming and -breaking processes operative at complex multimetallic active sites.

DOI: 10.1021/jacs.4c13492

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c13492