van Leest Nicolaas P, de Zwart Felix J, Zhou Minghui, de Bruin Bas
Homogeneous, Supramolecular and Bio-Inspired Catalysis Group, van 't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
JACS Au. 2021 Jul 6;1(8):1101-1115. doi: 10.1021/jacsau.1c00224. eCollection 2021 Aug 23.
Advances in (spectroscopic) characterization of the unusual electronic structures of open-shell cobalt complexes bearing redox-active ligands, combined with detailed mapping of their reactivity, have uncovered several new catalytic radical-type protocols that make efficient use of the synergistic properties of redox-active ligands, redox-active substrates, and the metal to which they coordinate. In this perspective, we discuss the tools available to study, induce, and control catalytic radical-type reactions with redox-active ligands and/or substrates, contemplating recent developments in the field, including some noteworthy tools, methods, and reactions developed in our own group. The main topics covered are () tools to characterize redox-active ligands; () novel synthetic applications of catalytic reactions that make use of redox-active carbene and nitrene substrates at open-shell cobalt-porphyrins; () development of catalytic reactions that take advantage of purely ligand- and substrate-based redox processes, coupled to cobalt-centered spin-changing events in a synergistic manner; and () utilization of redox-active ligands to influence the spin state of the metal. Redox-active ligands have emerged as useful tools to generate and control reactive metal-coordinated radicals, which give access to new synthetic methodologies and intricate (electronic) structures, some of which are yet to be exposed.
对带有氧化还原活性配体的开壳钴配合物异常电子结构进行（光谱）表征的进展，结合对其反应活性的详细映射，揭示了几种新的催化自由基型反应方案，这些方案有效利用了氧化还原活性配体、氧化还原活性底物及其配位金属的协同性质。从这个角度出发，我们讨论了用于研究、诱导和控制涉及氧化还原活性配体和/或底物的催化自由基型反应的工具，同时考虑到该领域的最新进展，包括我们自己团队开发的一些值得注意的工具、方法和反应。涵盖的主要主题包括：（）表征氧化还原活性配体的工具；（）在开壳钴卟啉中利用氧化还原活性卡宾和氮烯底物的催化反应的新型合成应用；（）利用基于配体和底物的纯氧化还原过程并与钴中心自旋变化事件协同发生的催化反应的开发；以及（）利用氧化还原活性配体影响金属的自旋状态。氧化还原活性配体已成为生成和控制反应性金属配位自由基的有用工具，这为新的合成方法和复杂的（电子）结构开辟了道路，其中一些结构尚未被揭示。
