Spectroscopically Characterized Synthetic Mononuclear Nickel–Oxygen Species

Abstract

Iron, copper, and manganese are the predominant metals found in oxygenases that perform efficient and selective hydrocarbon oxidations and for this reason, a large number of the corresponding metal–oxygen species has been described. However, in recent years nickel has been found in the active site of enzymes involved in oxidation processes, in which nickel–dioxygen species are proposed to play a key role. Owing to this biological relevance and to the existence of different catalytic protocols that involve the use of nickel catalysts in oxidation reactions, there is a growing interest in the detection and characterization of nickel–oxygen species relevant to these processes. In this Minireview the spectroscopically/structurally characterized synthetic superoxo, peroxo, and oxonickel species that have been reported to date are described. From these studies it becomes clear that nickel is a very promising metal in the field of oxidation chemistry with still unexplored possibilities.