Synthesis, characterization and X-ray crystal structures of 2-chloro-N'-(2-hydroxy-5-methoxybenzylidene)benzohydrazide and its oxidovanadium(V) complexes with catalytic oxidation property

A new aroylhydrazone compound 2-chloro-N'-(2-hydroxy-5-methoxybenzylidene)benzohydrazide (H2L) was synthesized. With the aroylhydrazone compound and 2-hydroxybenzohydroxamic acid (HLa) or maltol (HLb) as ligands, two new oxidovanadium(V) complexes [VOLLa]∙CH3OH (1) and [VOLLb] (2) were synthesized. Both the aroylhydrazone and the complexes have been characterized by elemental analysis, IR, UV-Vis and 1H NMR spectra, as well as single crystal X-ray determination. X-ray analysis indicates that the V atoms in the complexes are in octahedral coordination. Crystal structures of H2L and the complexes are stabilized by hydrogen bonds. Thermal analysis of the complexes was performed. The complexes show effective catalytic property for the epoxidation of styrene, with conversion over 80% and selectivity over 90%.