ANTIMICROBIAL ACTIVITIES OF SYNTHESIZED Mn(II), Ni(II) AND Pt(II) MIXED LIGAND COMPLEXES OF ISONICOTINYLHYDRAZIDE AND 4-HYDROXY-3-METHOXYBENZALDEHYDE WITH ANILINE

Abstract

This research work synthesized vanillin-isonicotinylhydrazone (ISVN) at room temperature by the condensation reaction of isonicotinylhydrazide with 4-hydroxy-3-methoxybenzaldehyde. The synthesized ligand was used to prepare the mixed ligand complexes of Mn(II), Ni(II), Cu(II) and Pt(II) with aniline as secondary ligand. The synthesized compounds were characterized using physical methods such as solubility, melting points, conductivity and spectroscopic methods using infrared and UV-vis spectroscopy. The zones of inhibition were determined by the agar well diffusion method while the MIC, MBC and MFC were carried out by agar dilution technique on strains of E. coli, S. aureus, S. typhi, C. albicans, A. niger and T. rubrum and results compared with streptomycin and fluconazole. The melting points of the ligands and the mixed ligand complexes were found to be very high (211.6-241.8 oC) while the measured conductivities were very low (0.03-1.03 µS). The infrared spectral data available proved that the ISVN coordinated to the metal ions through its azomethine nitrogen and the phenolic oxygen atom of the vanillin ring. The second ligand, aniline coordinated the metal ions through its nitrogen atom. From the UV spectral data coupled with the infrared data and literature of the specified metal ions, octahedral geometry was proposed for the metal complexes while a square planar geometry was proposed for the platinum (II) complexes. The antimicrobial studies showed that the prepared ligands and the complexes had good antimicrobial activities and can be used as raw materials in pharmaceutical industries for the preparation of new drugs.