Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, Shaanxi, China.
Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany.
Chem Soc Rev. 2021 Apr 26;50(8):4804-4811. doi: 10.1039/d0cs01456g.
Oxygen evolution and reduction reactions are fundamental processes in biological energy conversion schemes, which represent an attractive method for artificial energy conversion for a world still largely depending on fossil fuels. A range of metalloenzymes achieve these challenging tasks in biology by activating water and dioxygen using cheap and abundant transition metals, such as iron, copper, and manganese. High-valent metal-oxo/oxyl, metal-superoxo, and/or metal-(hydro)peroxo species are common reactive intermediates that are found in the O-O bond formation and activation reactions. The transient nature of the metal-oxygen intermediates has, however, prevented their isolation and characterization in most cases. As a consequence, unambiguous mechanistic assignments in the O-O bond formation and cleavage processes in biological and chemical entries remain elusive, especially for the intermediates and mechanisms involved in the O-O bond formation reactions. This viewpoint article aims at summarizing the information obtained to date in enzymatic and biomimetic systems that fuels the debate regarding the nature of the active oxidants and the mechanistic uncertainties associated with the transition metal-mediated O-O bond formation and cleavage reactions.
氧的产生和还原反应是生物能量转换方案中的基本过程，它们为仍然在很大程度上依赖化石燃料的世界提供了一种有吸引力的人工能量转换方法。一系列金属酶通过使用廉价且丰富的过渡金属（如铁、铜和锰）来激活水和氧气，从而实现这些具有挑战性的任务。高价金属-氧代/氧基、金属过氧和/或金属-（氢）过氧物种是常见的反应中间体，存在于 O-O 键形成和活化反应中。然而，金属-氧中间体的瞬态性质使得它们在大多数情况下无法被分离和表征。因此，在生物和化学领域中，O-O 键形成和断裂过程中的明确机制分配仍然难以捉摸，特别是对于涉及 O-O 键形成反应的中间体和机制。本文旨在总结目前在酶和仿生系统中获得的信息，这些信息推动了关于活性氧化剂的性质以及与过渡金属介导的 O-O 键形成和断裂反应相关的机制不确定性的争论。
