Synthesis Of Novel N4 Tetradentate Click Ligands And Catalytic Properties Of Their Complexes

The research on MMO (methane monooxygenase) has emerged as a hot project in bioinorganic field, which has attracted much attention. Under mild conditions, the bio-inspired catalysts based on MMO can selectively and efficiently catalyze oxidation reactions of a large range of alkenes and by using H2O2 or peracetic acid. It may give a promising way to substitute present oxidation processes. In rencent years, several impressive catalytic systems have been detailed, but there is limited access to these N4 tetradentate ligands, and most of them are based on a pyridyl-framework. The limited modification methods for the pyridyl-framework result in the limited synthetic variations of them. Thus it is necessary to develop a novel non-pyridyl-based N4 tetradentate ligand system and an efficient construction method for such a system Herein, we report the"click"syntheses of triazole-based N4 tetradentate ligands 1a–d, and the X-ray structures of their metal complexes 4a–d, 5a, 6a and 7a. To demonstrate the application of our non-pyridyl-based ligands in catalysis, their manganese (MnII) complexes 4a–d have been used in the epoxidation of various terminal aliphatic olefins with peracetic acid, in which these complexes show good catalytic activities, and feature with low catalyst loading, fast conversion and high yields .It is a significant advance that this system provides an operationally simple and rapid way to epoxidize a wide scope of olefins .