Hydrocarbon oxidation catalyzed by manganese and iron complexes with the hexadentate ligand N,Nʹ-di(ethylacetate)-N,N′-bis(2-pyridylmethyl)-1,2-ethanediamine

Analogs of recently reported manganese and iron catalysts for alkene and alkane oxidation reactions have been prepared with the potentially hexadentate ligand N,Nʹ-di(ethylacetate)-N,N′-bis(2-pyridylmethyl)-1,2-ethanediamine (debpn). The Mn(II) and Fe(II) complexes, which were previously found to be heptacoordinate in the solid state, are capable of catalyzing alkene epoxidation and aliphatic C–H activation reactions, although these activities are inferior to those of related complexes with less coordinating ligands. The hydrocarbon oxidation catalyzed by iron is more severely disrupted. Cyclic voltammetry indicates that the +2 oxidation states for both debpn complexes’ metal ions are stabilized by the two additional chelate arms. Product analysis of the C–H activation and olefin epoxidation chemistries suggest that ligand-substrate steric interactions may exert additional inhibitory effects on the reactivity for the manganese catalysts.