Synthesis, X-Ray Crystal Structures and Catalytic Epoxidation of Oxidovanadium(V) Complexes Derived from N’-(5-Chloro-2-Hydroxybenzylidene)-3-Methylbenzohydrazide

An aroylhydrazone compound N’-(5-chloro-2-hydroxybenzylidene)-3-methylbenzohydrazide (H2L) has been synthesized and characterized by elemental analysis, infrared and electronic spectra, and 1H NMR spectrum. With the aroylhydrazone and maltol (HLa) or ethyl maltol (HLb) as ligands, two oxidovanadium(V) complexes, [VOLLa] (1) and [VOLLb] (2), have been synthesized and characterized by elemental analysis, infrared and electronic spectra, and 1H NMR spectra. Structures of the complexes were further confirmed by single crystal X-ray determination. The V atoms in the complexes are coordinated by the ONO donor atoms of the aroylhydrazone ligand L, OO donor atoms of maltolate (La) or ethyl maltolate (Lb) ligand, and one oxido O atom, forming octahedral coordination. The complexes function as effective olefin epoxidation catalysts with hydrogen peroxide as terminal oxidant and sodium hydrogen carbonate as a co-catalyst.