MnII complexes with tetradentate N4 ligands: Highly efficient catalysts for the epoxidation of olefins with H2O2

Abstract: A series of Mn-complexes with tetradentate N4 ligands, introducing aromatic groups into 2-pyridylmethyl positions of N,N′-dimethyl-N,N′-bis(2-pyridylmethyl)ethane-1,2-diamine ( mep ), N,N′-dimethyl-N,N′-bis(2-pyridylmethyl)cyclohexane-trans-diamine ( mcp ), have been synthesized and applied for epoxidation of olefins using H2O2 as the oxidant. The Mn-complexes still possessed an octahedral mononuclear structure in a cis-α topology. These complexes showed good regioselectivity, high yields and turnover frequency (even up to 228,000h−1) with low catalyst loading (0.1–0.01mol%) for epoxidation of a family of olefins (including internal aromatic olefins, internal and terminal aliphatic olefins and diolefins). [Copyright &y& Elsevier]