Oxovanadium(V) complexes incorporating tridentate aroylhydrazoneoximes: Synthesis, characterizations and antibacterial activity

Some new oxovanadium(V) complexes, [VOL1–3(OEt)(EtOH)] (1–3), have been reported, which were obtained from the reaction of the Schiff bases H2L1–3 (where H2L1 = the salicylhydrazone of diacetyl monoxime; H2L2 = the 4-methoxy salicylhydrazone of diacetyl monoxime and H2L3 = the 4-hydroxy salicylhydrazone of diacetyl monoxime) with VO(acac)2 in a 1:1 molar ratio. Three 4-R-aroylhydrazoneoximes (V) have been used as ligands in the present study, differing in the inductive effect of the substituent R (R = H, OCH3 and OH), in order to observe their influence, if any, on the redox potentials and biological activity of the complexes. All the synthesized ligands and metal complexes were successfully characterized by elemental analysis, IR, UV–Vis and NMR spectroscopy. An X-ray diffraction study of [VOL1(OEt)(EtOH)] (1) reveals that the metal center has a distorted octahedral O5N coordination sphere, where the O,N,O donor ligand and the ethoxo group constitute a satisfactory O3N basal plane. Cyclic voltammetry of the complexes show a quasi-reversible cyclic voltammetric response in the potential range 0.29–0.36 V involving a single electron V(V)–V(IV) reduction. The complexes have also been screened for their antibacterial activity against Escherichia coli, Bacillus, Proteus and Klebsiella. Minimum inhibitory concentrations of these complexes and the antibacterial activities indicate compound 1 as the potential lead molecule for drug design.

Some new oxovanadium(V) complexes, [VOL1–3(OEt)(EtOH)] (1–3), have been reported, which were obtained from the reaction of the Schiff bases H2L1–3 with VO(acac)2. Three 4-R-aroylhydrazoneoximes have been used as the ligands in the present study, differing in the inductive effect of the substituent R (R = H, OCH3 and OH), in order to observe their influence, if any, on the redox potentials and biological activity of the complexes. All the synthesized complexes were successfully characterized by elemental analysis, IR, UV–Vis, NMR spectroscopy and electrochemical measurements. X-ray diffraction measurements of 1, [VO(L1)(OEt)(EtOH)], have been carried out. All the complexes have been screened for their antibacterial activity against Escherichia coli, Bacillus, Proteus and Klebsiella.Figure optionsDownload as PowerPoint slide