Co(III), Ni(II), Pd(II) and Pt(II) complexes derived from new benzimidazole-based imine ligands: Preparation, structure, antibacterial, HSA binding and DNA interaction studies

Abstract

We present here the synthesis of a novel imine base ligand, 2-[(1H-Benzoimidazol-2-ylmethylimino)-methyl]-5-methoxyphenol (HBIM), and its complexes with Co(III), Ni(II), Pd(II), and Pt(II). The ratios of HBIM to metal ions in the synthesis of the metal complexes (TM1-TM4) were 2:1 and 1:1, respectively. Elemental analysis, FT-IR, UV–Visible, NMR, mass spectroscopy, powder XRD, conductance, and magnetic moment measurement were used to clarify the structure of the synthesized ligand and its coordination complexes. Additionally, in vitro antibacterial activity of the compounds was evaluated against a variety of types of bacteria, including B. subtilis, S. aureus, L. monocytogenes, E. coli, V. cholera, and P. aeroginosa. It was shown that metal complexes interacted with human serum albumin (HSA). The findings clearly suggested that the platinum complex (TM4) had a notable interaction with the HSA protein among the produced complexes. Also, it showed that a static quenching process is most likely the mechanism by which complexes quench HSA fluorescence, and that hydrogen binding reactions or van der Waals forces mostly drive entropy in the spontaneous binding contact. Furthermore, the synthesized compounds' binding propensity was assessed using pBR322 DNA cleavage and the calf thymus DNA (CT-DNA) interaction.