Microwave Synthesis, Spectral, Thermal and Antimicrobial Studies of Some Ni(II) and Cu(II) Schiff Base Complexes

Schiff bases have been synthesized by condensing nicotinamide with methyl isobutyl ketone (MKN) and 2-hydroxy acetophenone (HAN). Metal complexes have been prepared by interacting these Schiff bases with metal ions viz. Ni(II), Cu(II) 1:2 (metal:ligand) ratio. These compounds have been synthesized by conventional as well as microwave methods and characterized by elemental analysis, FT-IR, UV-Vis, FAB-mass, ESR, molar conductance, and thermal analysis. FAB mass and thermal data show degradation pattern of the complexes. The complexes are colored and stable in air at room temperature. The structure of the ligands were elucidated by spectral studies which indicate the presence of two or three coordinating groups in ligands which may be oxygen atom of the phenolic -OH group, the nitrogen atom of the azomethine (C=N) group and the oxygen atom of the carbonyl group. The thermal behavior of metal complexes shows that the hydrated complexes loses water molecules of hydration in the first step; followed by decomposition of ligand molecules in the subsequent steps. The solid state electrical conductivity of the metal complexes has also been measured. Solid state electrical conductivity studies reflect semiconducting nature of the complexes. The Schiff bases and metal complexes show good activity against the Gram-positive bacteria; Staphylococcus aureus and Gram-negative bacteria; Escherichia coli and fungi Aspergillus niger and Candida albicans. The antimicrobial results also indicate that the metal complexes are better antimicrobial agents as compared to the Schiff bases.