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 (H 2 L) has been synthesized and characterized by elemental analysis, infrared and electronic spectra, and 1 H NMR spectrum. With the aroylhydrazone and maltol (HL a ) or ethyl maltol (HL b ) as ligands, two oxidovanadium(V) complexes, [VOLL a ] (1) and [VOLL b ] (2), have been synthesized and characterized by elemental analysis, infrared and electronic spectra, and 1 H 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 (L a ) or ethyl maltolate (L b ) 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.