Microwave synthesis, spectral, thermal and antimicrobial studies of some Ni(II) and Cu(II) Schiff base complexes

Bidentate and tridentate (NO), (ONO) Schiff bases have been synthesized by condensing methyl isobutyl ketone with 2-amino-4-chlorophenol and 2-hydroxy acetophenone with isonicotinic acid hydrazide. The 1:1 or 1:2 metal complexes have been prepared by interacting these Schiff bases with metal ions viz. Ni(II), Cu(II). These compounds have been synthesized by conventional as well as microwave methods and characterized by elemental analysis, FT-IR, UV-Vis, ESR, molar conductance, thermal analysis and X-ray diffraction. The complexes are colored and stable in air at room temperature. 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. Crystal data of [Ni(HINH)(H2O)]Cl.3H2O complex a = b =13.9338 , c = 34.7975 , V = 6755.96 3, Z = 12, Dobs = 1.2421g/cm3, Dcal 1.2847g/cm3, reflect that this complex has crystallized in orthorhombic system. 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.