Neutral dioxovanadium(V) complexes of biomimetic hydrazones ONO donor ligands of bioinorganic and medicinal relevance: Synthesis via air oxidation of bis(acetylaceto-nato)oxovanadium(IV), characterization, biological activity and 3D molecular modeling

The interaction of bis(acetylacetonato)oxovanadium(IV), [VO(acac)2] with biomimetic hydrazone ONO donor ligands HL in 1:1 mole ratio [where, HL = N-(4′-benzoylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-isonicotinic acid hydrazide (bmphp-inH, I), N-(4′-butyrylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-isonicotinic acid hydrazide (bumphp-inH, II), N-(4′-acetylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-isonicotinic acid hydrazide (amphp-inH, III), N-(3′-methyl-1′-phenyl-4′-propionylidene-2′-pyrazolin-5′-one)-isonicotinic acid hydrazide (mphpp-inH, IV) and N-(4′-iso-butyrylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-isonicotinic acid hydrazide (iso-bumphp-inH, V)] in a mixed solvent (ethanol–methanol, 1:10) via aerial oxidation for 2–3 days yield dioxovanadium(V) complexes of composition [VO2(L)(H2O)] · H2O. The compounds so obtained were characterized on the basis of elemental analyses, thermogravimetry, vanadium determination, IR, Electronic, 51V NMR, 1H NMR and mass spectral studies. The 3D molecular modeling and analysis for bond lengths and bond angles have also been carried out for one of the representative compounds, [VO2(ampph-in)(H2O)] (3).