Synthesis, structure, reactivity and electrochemical studies of oxovanadium(IV) chelates with some carboxyamide derivatives

Oxovanadium(IV) chelates of (2Z)-4-(2-acetylhydrazino)-4-oxobut-2-enoic acid (AOBEH), 4-(2-acetylhydrazino)-4-oxobutanoic acid (AOBAH), 2-[(2-acetylhydrazino)carbonyl]benzoic acid (AHCBH), (2Z)-4-[(2-cyanophenyl)amino]-4-oxobut-2-enoic acid (COBEH), 4-[(2-cyanophenyl)amino]-4-oxobutanoic acid (COBAH), 2-[{(2-cyanophenyl)-amino]carbonyl}benzoic acid (CACBH), (2Z)-4-(1H-benzimidazol-2-ylamino)-4-oxobut-2-enoic acid (BOBEH), 4-(1H-benzimidazol-2-ylamino)-4-oxobutanoic acid (BOBAH) and 2-[(1H-benzimidazol-2-ylamino)carbonyl]benzoic acid (BYCBH) have been prepared and characterized by elemental analysis, magnetic moments, IR, electronic, NMR, ESR spectra and thermal studies. The magnetic moments and electronic spectral studies suggest square pyramid geometry to all the oxovanadium(IV) complexes and distorted octahedral geometry to the vanadium(IV) complexes with O 4 and Cl 2 O 4 as donor sets from the ligands. The electrochemical studies by cyclic volammograms produced irreversible single oxidation peak for V IV -V V vs SCE ranging from 0.43-0.64 V rationalized by the basicity of ligands.