The use of dioxygen by biochemical (heme) and other porphyrinoid catalysts for the oxidation of substrates (e.g. C-H to C-OH, sulfide to sulfoxide) is of fundamental importance to a range of biological and synthetic transformations. This presentation will describe our recent results on the activation of dioxygen by Mn porphyrinoid complexes and the subsequent generation of high-valent Mn-oxo species. This chemistry involves photoactivation of an Mn(III) complex and the proton-controlled, catalytic oxidation of substrates, including benzylic hydroxylation of toluene derivatives and sulfoxidation of thioethers using only air and light. The tuning of high-valent Mn-oxo intermediates by Bronsted and Lewis acids will be described. The redox reactivity of the non-innocent porphyrinoid ligand can also play an important role in oxidation chemistry, and the involvement of porphyrinoid π-radical cation in the oxidation of substrates will be discussed.

Tuning the metal–dioxygen, –oxo, –hydroxo, and ligand reactivity landscape in heme-type complexes

251st National Meeting (2016)

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