Tracking an FeV(O) Intermediate for Water Oxidation in Water

High-valent iron-oxo species are appealing in conducting O–O bond formation for water oxidation reaction. However, their high reactivity poses a great challenge to dissection of their chemical transformations. Herein, we introduce an electron-rich and oxidation-resistant ligand, 2-[(2,2’-bipyridin)-6-yl]propan-2-ol to stabilize such fleeting intermediates. Advanced spectroscopies and electrochemical studies demonstrate a high-valent FeV(O) species formation in water. Combining kinetic and oxygen isotope labelling experiments and organic reactions indicates that the FeV(O) species is responsible for O–O bond formation via water nucleophilic attack under the real catalytic water oxidation condition.

高价铁氧物种（high-valent iron-oxo species）在催化水氧化反应的氧氧键形成过程中具有重要应用潜力。然而，其极高的反应活性为解析其化学转化机制带来了极大挑战。本文中，我们引入一种富电子且抗氧化的配体——2-[(2,2’-联吡啶)-6-基]丙-2-醇（2-[(2,2’-bipyridin)-6-yl]propan-2-ol），以稳定这类瞬态中间体。先进光谱学技术与电化学研究证实，该体系在水溶液中生成了FeV(O)物种。结合动力学实验、氧同位素标记实验与有机反应的结果表明，在实际催化水氧化条件下，该FeV(O)物种正是通过水亲核进攻路径介导了氧氧键的形成。