Physicochemical Studies and Biological Activity of Mixed Ligand Complexes Involving Bivalent Transition Metals, 2-Aminomethylthiophenyl-4-Bromosalicylaldehyde Schiff Base and Glycine

Abstract

The Mixed-ligand complexes of Co(II), Ni(II), Mn(II) and Zn(II) with 2-aminomethylthiophenyl-4-bromosalicylaldehyde Schiff base (ATS) and glycine as a representative example of amino acids have been achieved. These complexes namely [Ni(ATS)(Gly)] (1), [Co(ATS)(Gly)].H₂O (3) [Mn(ATS)(Gly)].2H₂O (2)  and [Zn(ATS)(Gly)] (4) were characterized by elemental, molar conductance, infrared, magnetic moment, and electronic spectra. ATS behaves as mononegatively charged bidentate ligand with coordination through azomethine nitrogen and phenolate oxygen groups while glycine acts as monobasic bidentate ligand is coordinated via amino and ionized carboxylate group after deprotonation. The low molar conductance values suggest the non-electrolytic nature of these complexes. The magnetic and spectral data indicates a square planar geometry for Ni²⁺ complex, tetrahedral geometry for Zn²⁺ and octahedral geometry for both Mn²⁺ and Co²⁺ complexes. The isolated chelates have been screened for their antimicrobial activity.

Keywords: Schiff base, Nickel(II); Glycine; Electronic Spectra; antibacterial activity.