Synthesis, spectral, thermal, electrochemical and antibacterial studies of oxomolybdenum(v) and dioxomolybdenum(vi) complexes with 2,3-dimethyl-1-phenyl-4-(5-chloro-2-hydroxybenzylideneamino )pyrazol- 5-one

Abstract

The Schiff base 2,3-dimethyl-1-phenyl-4-(5-chloro-2-hydroxybenzylideneamino)pyrazol-5-one (AAPCSAL) was prepared by reacting 4-amino antipyrine with 5-chlorosalicylaldehyde and a series of metal complexes with this ligand were synthesised by reaction with oxomolybdenum(V) and dioxomolybdenum(VI) having the compositions [MOOLCl 2 ], [MoOL(NCS)Cl], [MoOL(NO 3 )Cl], [MoOL(CIO 4 )Cl], [MoO 2 LCl], [MoO 2 L(NCS)], [MoO 2 L(NO 3 )] and [MoO 2 L(CIO 4 )] (L = AAPCSAL). The complexes were characterized on the basis of elemental analyses, molar conductance, magnetic susceptibility data, UV-visible, IR, ESR and NMR spectral studies. NMR and Infrared spectral data suggest that the ligand behaves as a monobasic tridentate chelating agent with ONO donor sequence towards the metal ion. X-Ray diffraction studies of complexes indicated orthorhombic crystal lattice with a = 7.2785 A, b = 9.4815 A and c = 14.5569 A. The ESR spectral data show that the metal-ligand bond has considerable covalent character. The electrochemical behaviour of the complex was investigated by cyclic voltammetry. The thermal properties of the complexes were investigated by thermogravimetric techniques. The ligand and the complexes have been screened for their antibacterial activities against gram positive and gram negative bacteria.