Synthesis, Spectral and Thermal Characterization of Selected Metal Complexes Containing Schiff Base Ligands with Antimicrobial Activities

Abstract

Selected metal complexes of Ni (II), Zn(II), Mn(II), Sn(II), Co(II) and Cd(II) ions were synthesized with three different synthesized Schiff base ligands. The ligands and metal complexes were isolated in the solid state from the reaction medium and characterized by molar conductivity measurement, magnetic susceptibility, Infrared, electronic spectral, thermal analysis and some physical measurements. The overall reactions were monitored by TLC analysis. Molar conductance study has shown that all the complexes were non-electrolytic in nature. FTIR studies suggested that Schiff bases act as deprotonated bidentate ligands and metal ions are attached with the ligands through N, O/S coordinating sites during complexation reaction. Magnetic susceptibility data coupled with electronic spectra revealed that Zn(II), Mn(II), Sn(II), and Cd(II) complexes have tetrahedral, Ni(II) complexes have a square planer and Co(II) complexes have octahedral geometry. Thermal analysis (TGA and DTG) data showed the possible degradation pathway of the complexes and also indicated that most of the complexes were thermally stable up to 200ºC. The Schiff bases and their metal complexes have been found moderate to strong antimicrobial activity.