Cobalt, Iron, and Manganese Metallocorroles in Catalytic Oxidation of Water. An Overview of the Synthesis, Selected Redox and Electronic Properties, and Catalytic Activities

Metallocorroles have emerged as interesting and versatile catalysts for a variety of redox reactions. These include clean-energy related small-molecule activation reactions such as proton, carbon dioxide and dioxygen reductions, as well as water oxidation, for which their ability to undergo several oxidation processes and reach high formal metal oxidation states makes them attractive catalysts. The diversity of substituent and central metal variations in metallocorroles opens up innumerable possibilities to tailor the properties and reactivity of this family of metallomacrocycles, and the richness of the (electro)chemistry and spectroscopy of metallocorroles allows for an array of instrumental techniques to be applied to the study of various (electro)catalytic processes. In this paper, we will succinctly summarize the synthesis of several cobalt, manganese, and iron metallocorroles with different apical ligands, discuss their redox properties and metal versus ligand centered oxidations through selected examples, and review their application in water oxidation (electro)catalysis. We will discuss some of the factors which affect the catalytic activity, some of the proposed mechanistic features and point out what we consider to be open questions and future perspectives in this field.