Synthetic High-Valent M-O-X Oxidants

High-valent metal-oxygen species (M-O-X species, as opposed to terminal metal-oxo, M=O, species) have been found to constitute a large family of capable oxidants. Herein, synthetic high-valent complexes with hydroxide, alkoxide and other anionic O-atom ligands, as well as O-Lewis acid adducts, are reviewed with a focus on their reactivity. Mn, Fe and Ru complexes are described, as well as recent additions to the field containing late transition metals (Co, Ni, Cu). These species are competent in a range of oxidations, and in particular they are capable of hydrogen atom transfer from strong C-H bonds. We explore how their reaction mechanisms and oxidising potency are modulated by the O-atom ligand.