Synthesis, characterization, anticancer activity and molecular docking of metal complexes bearing a new Schiff base ligand

2-((E)-((4-(((E)-4-Nitrobenzylidene)amino)phenyl)imino)methyl)naphthalen-1-ol, was synthesised followed by metalation with Fe(III), Co(III), Cu(II), Zn(II) and Ni(II) metals. The compounds were characterised by different methods CHN, AAS, IR, NMR, XRD, TGA and UV-Vis. The results reveal that the ligand has bidentate behavior, and it is bound with metals by a coordination bond through both the nitrogen atom of the azomethine group and the oxygen atom, this provided an octahedral geometry. The X-ray diffraction of the compounds indicate that the ligands and complexes of Co(III), Fe(III) and Zn(II) have a crystalline nature, whereas the Ni(II) and Cu(II) have an amorphous structure. The agar diffusion method (hole plate) was used to evaluate the ligand's and its complexes' antibacterial and antifungal effects on Salmonella enterica serovar typhi and Candida albicans, respectively. It was observed that the Fe(III) complex had the best activity among the compounds against microbial strains. Cytotoxicity of new metal complexes was also assessed against A549, HepG-2 and PC-3 cancer cells. Results demonstrated that the Cu(II) complex displayed the preeminent activity among the synthesised compounds against all the tested cell lines. Furthermore, molecular docking simulation revealed that the Fe(III) complex is shown to have a high affinity with the active sites of two targets of microbial strains. Also, the Cu(II) complex shown to has a high affinity with the active sites of three targets of A-549, HepG-2 and PC-3 cancer cells, which was confirmed by the formation of the different modes of interaction.Communicated by Ramaswamy H. Sarma