Redox Chemistry and Electrochemistry of Homoleptic Metal PhenolatesPATAI'S Chemistry of Functional Groups

The redox chemistry of aryl alcohols, or phenols, is of great interest because of their involvement in important biological and industrial processes. Phenol and its substituted analogs are facile one-electron reducing agents that are often involved in electrochemical, photochemical and radiation chemical electron transfer reactions. For these and many other reasons the interest of chemists in the metal phenolates has always been lively and a huge number of these complexes are known. In this chapter we describe the redox behavior of the more restricted set of homoleptic aryloxide complexes. The peculiarities of phenolates as ligands make them usually unable to stabilize a metal in different redox states and, very often, reduction of the metal is accompanied by the release of one or more of the ligands and/or by the formation of polynuclear compounds. This may give rise to a complicated pattern in the redox chemistry of these complexes, but may also open the way to a rich, redox-driven, chemistry of this class of compounds, which, apparently, is still largely unexplored.