Synthesis, characterization, biological (in vitro) activity and electrochemical studies of mixed-ligand copper (II) and cobalt (II) complexes with picolinic acid and imides

Abstract

• Synthesis of mixed ligand copper (II) and cobalt (II) complexes with imides and picolinic acid. • Characterized by FT-IR, UV–visible spectroscopy. • Electrochemical behavior of mixed-ligand copper (II) and cobalt (II) complexes (1–4) by using cyclic voltammetry (CV). • Biological activity of mixed-ligand copper (II) and cobalt (II) complexes (1–4). Mixed ligand copper (II) and cobalt (II) complexes viz; [Cu(6-pic) 2 (succinimie) 2 ] 1; [Cu(6-pic) 2 (phthalimide) 2 ] 2; [Co(6-pic) 2 (succinimide) 2 ] 3; [Co(6-pic) 2 (phthalimide) 2 ] 4 have been synthesized with picolinic acid (6-picolinic acid) and imides (imides = succinimide and phthalimide), used as primary and secondary ligands respectively. All these mixed-ligand complexes (1–4) were characterized by elemental analysis (C H N), molar conductance, room temperature magnetic susceptibility, FT-IR, and UV–visible spectroscopy. The electrochemical study of all these complexes were performed in aqueous medium, containing 0.2 M NaClO 4 as supporting electrolyte at glassy carbon working electrode (GCE) vs Ag/AgCl reference electrode by using cyclic voltammetric (CV). The complexes 1, 2 and 3, 4 were exhibited Cu 2+/+ and Co 3+/2+ / Co +/2+ diffusion controlled quasi-reversible single electron transfer redox couples. The cobalt (II) complexes 3 and 4 are biologically (in vitro) more active compare to copper (II) complexes 1 and 2 against microorganisms with antibacterial and antifungal drugs.