Abstract
The stable metal complexes of transition metals with benzimidazole derivatives lead to improved physicochemical and biological properties of these compounds. The development of antimicrobial agents becomes possible through complex design based on benzimidazole-derived compounds. The research focused on creating and analyzing bis((1H-benzo[d]imidazol-2-yl)methyl)sulfane (L) as a benzimidazole-derived ligand and studying its Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) metal complexes. The researchers synthesized the ligand and its metal complexes through sequential steps before using elemental analysis and FTIR and UV–Vis and 1H-NMR and conductivity and magnetic measurements for identification. The agar well diffusion method served to evaluate the antibacterial properties of the compounds against Staphylococcus aureus and Escherichia coli. The spectroscopic and analytical results showed that the imidazole nitrogen atoms of the ligand act as binding sites, while the thioether sulfur atom does not participate in coordination. The complexes showed tetrahedral structures that existed as [M(L)2]Cl2 or [M2(L)2(H2O)2]Cl2 compounds. The results from antibacterial tests revealed that metal complexation led to substantial improvements in biological activity. The Cu(II) complexes produced the largest inhibition zones, while the Zn(II) complexes showed the second-highest activity, and both complexes displayed better effects against S. aureus than E. coli. Benzimidazole-based ligands serve as effective building blocks for creating transition metal complexes, which show promising antimicrobial activity according to the research findings. The improved activity of Cu(II) and Zn(II) complexes indicates that chelation enhances both lipophilicity and bacterial membrane permeability.