Synthesis, Structural Characterization, Molecular Docking, Thermal Studies, and Antimicrobial Activity of Ni(II) Binuclear Complexes

A new hexadentate ligand, 3,3 '-{(1E,1 ' E)-[(4-chloro-1,2-phenylene)bis(azaneylylidene)]bis(methaneylylidene)}bis(2-hydroxybenzoic acid) (H4L) was synthesized by the condensation of 3-formylsalicylic acid with 4-chloro-1,2-phenylenediamine. The synthesized ligand forms mononuclear complex with Ni(II) and nuclear complexes containing some transition metal ions (Co2+, Fe2+, Ru2+, La2+, Cr2+, Mn2+, Pd2+, and Cu2+) in binary form. Ligand and its metal complexes were characterized physically as well as by using spectral techniques including ultraviolet visible spectroscopy, Fourier transform infrared spectroscopy. In addition, pharmacological activity was studied. All the compounds showed antibacterial and antifungal activities, but the metal complexes showed better activities as compared to the original ligand. The H4L ligand was discovered to be a potential inhibitor for the Helicobacter pylori protein in a molecular docking investigation. The above results suggest that both ligands and their metal complexes have the potential to be explored as active pharmaceutical agents.