OXOVANADIUM(IV) COMPLEXES OF BIOINORGANIC AND INDUSTRIAL RELEVANCE: SYNTHESIS AND CHARACTERIZATION OF SOME OXOVANADIUM(IV) COMPLEXES INVOLVING SCHIFF BASES DERIVED FROM BIOLOGICALLY ACTIVE 4-BENZOYL-3-METHYL-1-PHENYL-2-PYRAZOLIN-5-ONE AND CERTAIN AROMATIC AMINES

ABSTRACT

Seven new oxovanadium(IV) complexes, formed by the interaction of vanadyl sulfate pentahydrate and the Schiff bases, viz., N-(4′-benzoylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-p-anisidine (HL¹), N-(4′-benzoylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-m-phenitidine (HL²), N-(4′-benzoylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-p-toluidine (HL³), N,N-(4′-benzoylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-o-phenylenediamine (H₂L⁴), N,N-(4′-benzoylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-m-phenylenediamine (H₂L⁵), N,N-(4′-benzoylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-p-phenylenediamine (H₂L⁶) and N,N-(4′-benzoylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-benzidine (H₂L⁷) in aqueous-ethanol, are described. The resulting complexes were characterized by elemental analyses, molar conductances, magnetic and decomposition temperature measurements, electron spin resonance, IR and electronic spectral studies. They have the compositions, [VO(L′)₂(H₂O)], where HL′=HL¹, HL² or HL³, [VO(L′′)(H₂O)], where H₂L′′=H₂L⁴ or H₂L⁵ and [{VO(H₂O)(OH)}2(L′′′)], where H₂L′′′=H₂L⁶ or H₂L⁷. The compounds [{VO(H₂O)(OH)}₂(L⁶)] and [{VO(H₂O)(OH)}₂(L7)] were found to show subnormal magnetic moments. Suitable structures have been proposed for these complexes.

ACKNOWLEDGMENTS

The authors are thankful to Shri Arun Gurtoo, Vice-chancellor of this University, for encouragement, and Professor K. K. Mishra, Head, Department of Chemistry, for laboratory facilities and helpful discussion. We are grateful to the University Grants Commission, New Delhi (Project No. F.12-57/97 (SR-I), and the Council of Scientific and Industrial Research, New Delhi (Project No. 01 (1609)/99/EMR-II), for financial assistance. Analytical facilities provided by the Central Drug Research Institute, Lucknow, India, and the Regional Sophisticated Instrumentation Centre, Indian Institute of Technology, Chennai, India, are gratefully acknowledged.