Copper(II) complexes with bioactive carboxyamide: Synthesis, characterization and biological activity

Complexes of Cu(II) with bioactive carboxyamide ligands N′,N″-bis(3-carboxy-1-oxoprop-2-enyl)2-amino-N-arylbenzamidine, N′,N″-bis(3-carboxy-1-oxopropanyl)2-amino-N-arylbenzamidine and N′,N″-bis(3-carboxy-1-oxophenelenyl)2-amino-N-arylbenzamidine have been synthesized and characterized by various physico-chemical techniques. Mass spectrum explains the successive degradation of the molecular species in solution and justifies ML complexes. Vibrational spectra indicate coordination of amide and carboxylate oxygen of the ligands along with water molecules. Electronic spectra and magnetic susceptibility measurements reveal octahedral geometry for Cu(II) complexes. The EPR of the reported complex show g∥ > g⊥ > 2.0023 and G value within the range 2.08-4.49 are consistent with dx2−y2 ground state in an octahedral geometry. The voltammogram of the copper(II) complex shows a quasi-reversible redox process and a simple one electron process assignable to the Cu(II)/Cu(I) couple. Kinetic and thermodynamic parameters were computed from the thermal data using Coats and Redfern method, which confirm first order kinetics. The bio-efficacy of the ligands and its copper complexes have been examined against the growth of bacteria and pathogenic fungi in vitro to evaluate their antimicrobial potential. The results indicate that the ligand and its metal complexes possess notable antimicrobial properties.