Ablyasova, O. S.; Ugandi, M.; Boydas, E. B.; Santos, M. da Silva; Flach, M.; Zamudio-Bayer, V.; Römelt, M.; Lau, J. T.; Hirsch, K.: High-Spin Manganese(V) in an Active Center Analogue of the Oxygen-Evolving Complex. Journal of the American Chemical Society 147 (2025), p. 7336–7344
10.1021/jacs.4c14543
Open Access Version
Abstract:
In a comprehensive investigation of the dinuclear [Mn2O3]+ cluster, the smallest dimanganese entity with two μ-oxo bridges and a terminal oxo ligand, and a simplified structural model of the active center in the oxygen-evolving complex, we identify antiferromagnetically coupled high-spin manganese centers in very different oxidation states of +2 and +5, but rule out the presence of a manganese(IV)-oxyl species by experimental X-ray absorption and X-ray magnetic circular dichroism spectroscopy combined with multireference calculations. This first identification of a high-spin manganese(V) center in any polynuclear oxidomanganese complex underscores the need for multireference computational methods to describe high-valent oxidomanganese species.