Synthesis and characterization of oxomolybdenum(V) and dioxomolybdenum(VI) complexes derived from N’-(2-hydroxy-3-methoxybenzylidene)isonicotinohydrazide

Abstract

Several novel complexes of oxomolybdenum(V) and dioxomolybdenum(VI) were synthesized with the Schiff base, N’-(2-hydroxy-3-methoxybenzylidene)isonicotinohydrazide (HL) derived from 3-methoxysalicylaldehyde and isonicotinohydrazide. The complexes were characterized by elemental analyses, molar conductance and magnetic susceptibility, as well as IR, 1H-NMR, FAB mass and UV–Vis spectral studies. The complexes have the general formulae [MoO(L)XCl] and [MoO2(L)X], where X=NO3 or ClO4. The IR spectra of these complexes indicate that the ligand HL acts as a monoanionic tridentate chelating agent. The spectra indicate the monodentate mode of coordination for the nitrate and perchlorate groups. The X-ray diffraction studies of [MoO(L)NO3Cl] correspond to an orthorhombic crystal lattice with unit cell dimensions a = 15.49 Å, b = 12.44 Å and c = 10.11 Å. All the complexes were found to have distorted octahedral geometry. Thermal studies of the complex [MoO2(L)NO3] showed that it was stable up to 240 °C, above which it started to decompose. The optimized geometry of ligand and one of its complexes, [MoO(L)NO3Cl], have been obtained by a molecular mechanics method. Antibacterial studies of the present complexes show that the oxomolybdenum(V) complexes were more potent bactericides than the ligand and the dioxomolybdenum(VI) complexes.

Keywords

• oxomolybdenum(V)
• dioxomolybdenum(VI)
• 3-methoxysalicylaldehyde isonicotinoylhydrazone
• thermal analysis
• 3D modelling.