Biologically active new Fe(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes of N-(2-thienylmethylene)methanamine

Abstract

Iron(II), cobalt(II), nickel (II), copper (II), zinc(II) and cadmium(II) complexes of the type ML2Cl2, where M is a metal and L is the Schiff base N-(2-thienylmethylene)methanamine (TNAM) formed by the condensation of 2-thiophenecarboxaldehyde and methylamine, were prepared and characterized by elemental analysis as well as magnetic and spectroscopic measurements. The elemental analyses suggest the stoichiometry to be 1:2 (metal:ligand). Magnetic susceptibility data coupled with electronic, ESR and Mössbauer spectra suggest a distorted octahedral structure for the Fe(II), Co(II) and Ni(II) complexes, a square-planar geometry for the Cu(II) compound and a tetrahedral geometry for the Zn(II) and Cd(II) complexes. The infrared and NMR spectra of the complexes agree with co-ordination to the central metal atom through nitrogen and sulphur atoms. Conductance measurements suggest the non-electrolytic nature of the complexes, except for the Cu(II), Zn(II) and Cd(II) complexes, which are 1:2 electrolytes. The Schiff base and its metal chelates were screened for their biological activity against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa and the metal chelates were found to possess better antibacterial activity than that of the uncomplexed Schiff base.