Transition Metal Complexes with Polydentate Ligand: Synthesis, Characterization, 3D Molecular Modelling, Anticancer, Antioxidant and Antibacterial Evaluation

Abstract

A novel polydentate Schiff base, namely (N,N′-(azanediylbis(ethane-2,1-diyl))bis(2-(((E)-(2-hydroxynaphthalen-1-yl)methylene)amino)benzamide) has been prepared through the condensation reaction between N,N′-(azanediylbis(ethane-2,1-diyl))bis(2-aminobenzamide) and 2-hydroxy 1-naphthaldehyde. The ligand and its synthesized metal complexes with Co (II), Ni(II), Cu(II), Ru(III) and Pd(II) salts have been characterized on with the help of various physicochemical studies such as elemental analyses, molar conductance, magnetic, spectral (UV–Vis, EPR, 1H NMR, MS, IR), 3D molecular modeling and thermal studies. The researchers propose a distorted five coordinate, distorted octahedral or square planar geometry for Schiff base metal complexes. The ligand ligates as polydentate one and can coordinate with two or three metal ions to form bi- or tri-nuclear metal complexes. The kinetic and thermodynamic parameters of decomposition process were computed. The in vitro antitumor activity against human breast (MCF-7) and human hepatocarcinoma (HepG2) cell lines has been investigated. The results have shown that the compounds tested are potent anticancer agents. Moreover, the scavenging activity of the tested compounds on DPPH was evaluated and compared with antioxidants ascorbic acid. The results reveal that the scavenging activity is concentration -dependent; furthermore the Schiff base ligand, complexes [Co2(L)Cl2(H2O)]·2H2O (1), and [Pd3(L)Cl4]Cl2·2H2O (10) are more efficient in quenching DPPH than the standard. In addition, the antibacterial study results of the selected compounds assayed against two pathogenic bacteria, Streptococcus pyogenes as Gram-positive bacteria and Escherichia coli as Gram-negative bacteria have shown that these compounds exhibit a remarkably high antibacterial activity.