A novel cadmium(II) complex of bipyridine derivative: synthesis, X-ray crystal structure, DNA-binding and antibacterial activities

• Published in: Journal of biomolecular structure & dynamics 2020-01, Vol.38 (1), p.236-247
• Main Authors: Kondori, Tahere, Akbarzadeh-T, Niloufar, Abdi, Khatereh, Dušek, Michal, Eigner, Václav
• Format: Article
• Language: English
• Subjects: 55′-dimethyl-22′-bipyridine; Algorithms; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; antibacterial activity; Bacteria - drug effects; Cadmium - chemistry; Cd(II) complex; Chemistry Techniques, Synthetic; Crystallography, X-Ray; DNA - chemistry; DNA binding; Hydrogen Bonding; Ligands; Magnetic Resonance Spectroscopy; Microbial Sensitivity Tests; Models, Molecular; Molecular Structure; Pyridines - chemical synthesis; Pyridines - chemistry; Pyridines - pharmacology; Spectroscopy, Fourier Transform Infrared; Thermodynamics; X-ray crystallography
• ISSN: 0739-1102; 1538-0254
• DOI: 10.1080/07391102.2019.1570867

A mononuclear cadmium(II) complex of formula [Cd(5,5′-dmbipy) 2 (OAc) 2 ]·2H 2 O (5,5′-dmbipy = 5,5′-dimethyl-2,2′-bipyridine and OAc = acetato ligand) has been synthesized and characterized by FT-IR, UV-Vis, 1 H-NMR, elemental analysis and single-crystal X-ray structure analysis. The molecular structure of the complex shows a distorted tetragonal antiprism CdN 4 O 4 coordination geometry around the cadmium atom, resulting in coordination by four nitrogen atoms from two 5,5′-dmbipy ligands and four oxygen atoms from two acetate anions. The interaction of this complex to FS-DNA (fish sperm DNA) has also been studied by electronic absorption, fluorescence and gel electrophoresis techniques. Binding constant (K b ), Stern-Volmer constant (K sv ), number of binding sites (n) and bimolecular quenching rate constant (k q ) have been calculated from these spectroscopic data. These results have revealed that the metal complex can bind effectively to FS-DNA via groove binding. The calculated thermodynamic parameters (ΔH°, ΔS° and ΔG°) show that hydrogen bonding and van der Waals forces have an important function in the Cd(II) complex-DNA interaction. The antibacterial effects of the synthesized cadmium complex have also been examined in vitro against standard bacterial strains: one Gram-positive (Staphylococcus aureus, ATCC 25923) and one Gram-negative (Escherichia coli, ATCC 25922) bacteria, using disk diffusion and macro-dilution broth methods. The obtained results show that the Cd(II) complex exhibits a marked antibacterial activity which is significantly better than those observed for its free ligand and metal salt for both Gram-positive and Gram-negative bacteria. However, this metal complex is a more potent antibacterial agent against the Gram-positive than that of the Gram-negative bacteria. Communicated by Ramaswamy H. Sarma