Synthesis, Characterisation, and Biological Properties of Oxidovanadium(IV) 3,5-Dinitrosalicylhydroxamate Complexes

Abstract

The new oxidovanadium(iv) complexes of composition [VO(3,5(NO2)2C6H2(OH)CONHO)2] 1 and [VO(acac)(3,5(NO2)2C6H2(OH)CONHO)] 2 (where acac=(CH3COCHCOCH3)–] have been synthesised by the reactions of VOSO4·5H2O and [VO(acac)2] with potassium 3,5-dinitrosalicylhydroxamate (3,5-(NO2)2SHK) and characterised by elemental analyses, molar conductivity, magnetic moment measurements and FT-IR, UV-vis, and electron spin resonance (ESR) spectroscopies and mass spectrometry. Infrared spectra of complexes have indicated bonding through oxygen atoms of carbonyl and hydroxamic groups (O,O coordination). The magnetic moment, ESR, and mass spectra of the complexes suggested their monomeric nature, and a distorted square-pyramidal geometry around the vanadium has tentatively been proposed. The electrochemical behaviour of 1 and 2 has been studied by cyclic voltammetry. Thermal behaviour of the complexes studied by thermogravimetric and differential thermal analysis techniques has yielded VO2 as the decomposition product. The invitro antimicrobial activity of the ligand and complexes has been assayed against pathogenic bacteria and fungi by the minimum inhibitory concentration (MIC) method. The invitro antioxidant activity of the complexes has been determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging method.