Spectroscopic characterization and reactivity studies of a mononuclear nonheme Mn(III)-hydroperoxo complex

We report the first example of a mononuclear nonheme manganese(III)- hydroperoxo complex derived from protonation of an isolated manganese(III)- peroxo complex bearing an N-tetramethylated cyclam (TMC) ligand, [Mn ^III(TMC)(OOH)]²⁺. The Mn^III-hydroperoxo intermediate is characterized with various spectroscopic methods as well as with density functional theory (DFT) calculations, showing the binding of a hydroperoxide ligand in an end-on fashion. The Mn^III-hydroperoxo species is a competent oxidant in oxygen atom transfer (OAT) reactions, such as the oxidation of sulfides. The electrophilic character of the Mn ^III-hydroperoxo complex is demonstrated unambiguously in the sulfoxidation of para-substituted thioanisoles.