Deformylation Reaction by a Nonheme Manganese(III)-Peroxo Complex via Initial Hydrogen-Atom Abstraction

Metal–peroxo intermediates are key species in the catalytic cycles of nonheme metalloenzymes, but their chemical properties and reactivity patterns are still poorly understood. The synthesis and characterization of a manganese(III)–peroxo complex with a pentadentate bispidine ligand system and its reactivity with aldehydes was studied. Manganese(III)–peroxo can react through hydrogen‐atom ion reactions instead of the commonly proposed nucleophilic addition reaction. Evidence of the mechanism comes from experiments which identify a primary kinetic isotope effect of 5.4 for the deformylation reaction. Computational modeling supports the established mechanism and identifies the origin of the reactivity preference of hydrogen‐atom ion over nucleophilic addition. Schnapp' das H: Eine spektroskopische, kinetische und computerchemische Studie präsentiert Beweise für eine geschwindigkeitsbestimmende Wasserstoffatomabspaltung bei Reaktionen von Aldehyden an Nicht‐Häm‐Mangan(III)‐Peroxo‐Komplexen (siehe Bild: Mn braun, C grau, O rot, N blau, H weiß).