Syntheses and structures of N′-(5-bromo-2-hydroxybenzylidene)-4-methoxybenzohydrazide and its dioxomolybdenum(VI) complex with catalytic epoxidation property

A new Schiff base N-(5-bromo-2-hydroxybenzylidene)-4-methoxybenzohydrazide (H2BMH) and its dioxomolybdenum(VI) complex [MoO2(BMH)(EtOH)] have been synthesized and characterized by elemental analysis, IR spectra, and single crystal X-ray determination. The Schiff base crystallized in the orthorhombic space group P2(1)2(1)2(1) and the complex crystallized in the triclinic space group . The Schiff base coordinates to Mo through the phenolate O, imine N, and enolic O. The asymmetric unit of the complex contains two mononuclear dioxomolybdenum molecules. Each Mo is six-coordinate octahedral. The only significant difference between the complex and the ligand is the geometry involving donors. The coordination of the ligand to Mo is also reflected in the IR spectra. The complex shows high catalytic property and selectivity in epoxidation of cyclohexene with t-butylhydroperoxide as oxidant.