Syntheses, Characterization, and Crystal Structures of two Oxovanadium(V) Complexes with Insulin‐like Activity

Abstract

Two new oxovanadium(V) complexes, [VOL(mat)] (1) and [VOL(Et‐mat)] (2) (mat = maltolate, Et‐mat = ethyl maltolate), where L is the dianionic form of N′‐(3‐ethoxy‐2‐hydroxybenzylidene)‐3‐hydroxy‐4‐methoxybenzohydrazide (H2L), were prepared and characterized by elemental analysis, IR, UV/Vis, and 1H NMR spectra. The structures of the compounds were further confirmed by single‐crystal X‐ray diffraction. The hydrazone ligand coordinates to the V atoms through the phenolate oxygen, imino nitrogen, and enolate oxygen. The maltolate and ethyl maltolate ligands coordinated to the V atoms through the carbonyl oxygen and deprotonated hydroxyl oxygen. The V atom in each complex is in octahedral coordination. The complexes were administered intragastrically to both normal and alloxan‐diabetic mice for two weeks. The biological activity results show that the complexes at doses of 10.0 and 20.0 mg V·kg–1, can significantly decrease the blood glucose level in alloxan‐diabetic mice, but the blood glucose level in the treated normal mice was not altered.