Microwave-assisted synthesis, spectroscopic properties, thermal behaviour and antimicrobial activity of unsymmetrical Schiff base complexes of Ti(III), Cr(III), MoO2(VI) and WO2(VI)

Four unsymmetrical Schiff base metal complexes, [Ti(L)(Cl)(H2O)], [Cr(L)(Cl)(H2O)], [MoO2(L)].H2O and [WO2(L)].H2O (L=4-hydroxy-3-(1-(2-(1-(2-hydroxy-5-methylphenyl)ethylideneamino)cyclohexylimino)ethyl)-6-methyl-2H-pyran-2-one) have been synthesized and characterized by their elemental analyses, magnetic susceptibility, thermogravimetric analysis, molar conductance, infrared (IR) and electronic spectral measurements. The purity of the ligand and its metal complexes are confirmed by microanalysis, while the unsymmetrical nature of the ligand was confirmed on the basis of 1H-NMR & 13C-NMR spectroscopy. Comparison of the IR spectra of the Schiff base ligand and its metal complexes confirm that the Schiff base behaves as tetradentate and coordinated via N2O2 chromophore. The ligand and its metal complexes were screened for antimicrobial activities against E. coli MTCC 443, P. aeruginosa MTCC 424 and S. aureus MTCC 96 and fungal strains, C. albicans MTCC 227 and A. niger MTCC 282. The activity data show that the complexes are more potent antimicrobials than the parent ligand.