Antimicrobial and SOD activities of novel transition metal ternary complexes of iminodiacetic acid containing α-diimine as auxiliary ligand

Ternary complexes containing an α-diimine auxiliary ligand have been widely used as models for several mono and polynuclear metal enzymes. The present ternary complexes [M(IDA)(Phen)H2O]·xH2O (x = 2, 3 or 4) were prepared as novel antimicrobial agents employing reactions of Cu(OAc)2 or MCl2 (M = Co, Ni, Cr) with iminodiacetic acid (H2IDA) in the presence of 1,10-phenanthroline (Phen), whose chemical structure and bonding were elucidated by IR, FAB-Mass, 1H, 13C NMR, EPR spectral and elemental analyses. The antimicrobial activities against Escherichia coli (K-12), Bacillus subtilis (MTCC 121), Staphylococcus aureus (IOA-SA-22), Salmonella typhimurium (MTCC 98), Candida albicans, Aspergillus fumigatus and Penicillium marneffei (isolates from Department of Microbiology, Faculty of Agricultural Science, AMU) were investigated and significant activities were obtained. The superoxide dismutase activity of the Cu(II) complex was assessed by NBT assay. The single crystal X-ray structure for [Cu(IDA)(Phen)H2O]·2H2O indicates a triclinic unit cell in P-1 space group with structural parameters, a = 6.745(5), b = 10.551(5), c = 11.414(5) Å, α = 95.770(5), β = 91.396(5), γ = 92.518(5)° and presence of an extensive H-bonding and π–π stacking interactions which generate a supramolecular framework.

Graphical abstractTransition metal mixed-ligand complexes containing iminodiacetic acid as primary and α-diimine as auxiliary ligands have been synthesized, characterized and evaluated for their antimicrobial and SOD activities.Figure optionsDownload full-size imageDownload as PowerPoint slide