SYNTHESIS AND CHARACTERIZATION OF OXOVANADIUM (IV) COMPLEXES WITH ISATIN HYDRAZONES - Jitendra

The condensation of isatin with pyridine carboxylic acid hydrazides in methanol give rise to hydrazone ligands. By the reactions of oxovanadium(IV) sulphate with hydrazones in presence of sodium hydroxide in methanol [VO(L)H2O] type complexes were obtained. The complexes were characterized by elemental analyses, conductances, magnetic moments, TGA and spectral (IR, Electronic and EPR) data. The analytical data were compatible with a 1:1 metal to ligand stoichiometry. The electrical conductances of the complexes were consistent with their non-electrolytic nature. The presence of one water molecule in the complexes was confirmed by thermogravimetric analysis. The IR spectra of the oxovanadium(IV) complexes shows that, the ligands behave in a tridentate way. The room temperature X–band EPR spectra exhibit eight lines due to hyperfine splitting of 51V, whose nuclear spin number I = 7/2. This confirms the presence of a single vanadium (IV) cation, hence the complexes are monomer. The anisotropy is not observed due to rapid tumbling of molecules in solution at room temperature and only g–average values are obtained. The anisotropy is clearly visible in the spectra at liquid nitrogen temperature and bands due to g and g are observed separately. The g,g, Aand A values are in good agreement for a square–pyrimdal geometry.