Cis-Dioxo-molybdenum(VI) Schiff base complexes: Synthesis, crystal structure and catalytic performance for homogeneous oxidation of olefins

Abstract

The synthesis of two Mo(VI) tetradentate Schiff base complexes derived from 2,2′-dimethylpropylenediamine and aromatic aldehydes, (MoO2{hnaphnptn} (1) and MoO2{salnptn(3-OMe)2} (2)) is reported. Full characterization of these complexes was accomplished with elemental analyses, spectroscopic studies (1H NMR, IR, and UV–Vis) and X-ray structure analysis. X-ray crystallography studies reveal that these complexes adopt a distorted octahedral six-coordinate configuration formed by tetradentate Schiff base ligand and two binding oxygen atoms. Catalytic performance of the prepared molybdenum complexes for oxidation of different olefins with tert-butyl hydroperoxide was evaluated. These complexes were found to be an efficient and selective catalyst for the homogeneous oxidation of various olefins. MoO2{salnptn(3-OMe)2} with a methoxy groups on the salicylidene ring of the ligand promote the effectiveness of the catalyst.