Peroxomanganese complexes as an aid to understanding redox-active manganese enzymes

Over the past 7 years, there have been a significant number of studies describing the structural and electronic properties, as well as the chemical reactivity, of synthetic peroxomanganese adducts. Many redox-active manganese enzymes, including manganese-containing superoxide dismutases, extradiol catechol dioxygenases, and ribonucleotide reductases, are proposed to feature peroxomanganese intermediates in their catalytic cycles. The recent efforts to model these intermediates using synthetic complexes have thus provided a strong complement to mechanistic studies of the enzymes. This review provides both a summary and a perspective of work in this area, with an emphasis on the relationship between geometric and electronic structure and chemical reactivity for η2-peroxomanganese(III) and η1-alkylperoxomanganese(III) adducts.