Metal-based antibacterial agents: synthesis, characterization, and in vitro biological evaluation of cefixime-derived Schiff bases and their complexes with Zn(II), Cu(II), Ni(II), and Co(II)

Abstract

The zinc(II), copper(II), nickel(II), and cobalt(II) complexes of Schiff bases, obtained by the condensation of cefixime with furyl-2-carboxaldehyde, thiophene-2-carboxaldehyde, salicylaldehyde, pyrrol-2-carboxaldehyde, and 3-hydroxynaphthalene-2-carboxaldehyde, were synthesized and characterized by their elemental analyses, molar conductances, magnetic moments, IR, and electronic spectral measurements. Analytical data and electrical conductivity measurements indicated the formation of M : L (1 : 2) complexes, [M(L)₂(H₂O)₂] or [M(L)₂(H₂O)₂]Cl₂ [where M = Zn(II), Cu(II), Ni(II), and Co(II)] in which ligands are bidentate via azomethine-N and deprotonated-O of salicyl and naphthyl, furanyl-O, thienyl-S, and deprotonated pyrrolyl-N. The magnetic moments and electronic spectral data suggest octahedral complexes. The synthesized ligands, along with their metal complexes, were screened for their antibacterial activity against different bacterial strains. The studies show the metal complexes to be more active against one or more species as compared to the uncomplexed ligands.

Keywords:

• Metal-based
• Schiff bases
• Cefixime
• Antibacterial

Acknowledgments

Our sincere thanks are to the Higher Education Commission of Pakistan for providing financial support. We are grateful to University of Manchester, U.K., for providing us with the elemental analysis, NMR, and mass spectra. We are also thankful to HEJ Research Institute of Karachi, University of Karachi, Pakistan, where in the antibacterial assays were performed.