4-Fluoro-N′-(2-hydroxy-3-methoxybenzylidene) benzohydrazide and its oxidovanadium(V) complex: Syntheses, crystal structures and insulin-enhancing activity

Abstract

A hydrated hydrazone compound, 4-fluoro-N′-(2-hydroxy-3-methoxybenzylidene)benzohydrazide monohydrate (H2L · H2O), was prepared and characterized by elemental analysis, HRMS, IR, UV-Vis and 1H NMR spectroscopy. Reaction of H2L, kojic acid (5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one; Hka) and VO(acac)2 in methanol afforded a novel oxidovanadium(V) complex, [VO(ka)L]. The complex was characterized by elemental analysis, IR, UV-Vis and 1H NMR spectroscopy. Thermal analysis was also performed. Structures of H2L and the complex were further confirmed by single crystal structural X-ray diffraction. The vanadium complex is the first structurally characterized vanadium complex of kojic acid. Insulin-mimetic tests on C2C12 muscle cells indicate that the complex significantly stimulated cell glucose utilization with cytotoxicity at 0.11 g L-1.