Synthesis, Spectral, Thermal and Antimicrobial Investigation of Some New Co(II), Ni(II) and Cu(II) Schiff Base Complexes

Schiff base has been prepared by the condensation of 2-naphthylamine (NA) with 5bromosalicylaldehyde (BSA). The ligand (NABSA) was isolated and characterized. Metal complexes have been synthesized by the interaction of NABSA with metal ions viz. Co(II), Ni (II), and Cu(II) in 1:2 molar ratio respectively. These complexes have been characterized by FT-IR, electronic spectroscopy, conductance measurements, magnetic moment, EPR, thermal analysis (TGA/DTA) and antimicrobial studies. IR spectra show that NABSA is coordinated to the metal ions in a bidentate manner through azomethine-N and phenolic-O-atom. The measured molar conductance values indicate that the complexes are nonelectrolytes. The thermal behavior of metal complexes reveals that the hydrated complexes lose water molecules of hydration in the first step, followed by decomposition of ligand molecule in the subsequent steps. The antimicrobial results indicate that the metal complexes have better activity compared to Schiff base ligand. Keywords—Bidentate Schiff base ligand, Cobalt(II), Nickel(II), Copper(II), Biological activity.