Metal‐Catalyzed Oxidations, 4. The Reaction of Molybdenumperoxo Complexes with Brønsted and Lewis Acids

NMR studies of the reaction of complexes of the type (L‐L)MoO(O2)2 (L – L= bidentate ligand) with strong Brønsted and Lewis acids prove that protons are transferred preferentially to an η2‐peroxo and not to the oxo ligand. This behavior in proton transfer reactions is one critical point of the catalytic activity of such complexes in olefin epoxidation. EH calculations on the model complex (NH3)2MoO(O2)2 support the spectroscopic investigations.