Combined experimental and theoretical investigation of the (benzoimidazol-2-yl)-methanone ligand and its Ru(III) complex: structural elucidation, stability determination, corrosion inhibition, energy storage and bioactivity applications

Abstract

Bis-(6-nitro-1H-benzoimidazol-2-yl)-methanone (NBM) ligand and its NBM-Ru complex act as corrosion inhibitors were synthesized and characterized utilizing various analytical, spectroscopic and physicochemical tools. Correlation between experimental data afford that NBM ligand acts as tri-dentate NNO ligand to give octahedral geometry of NBM-Ru complex. DFT calculations were applied to confirm the structure and reactivity of the investigated compounds as corrosion inhibitors. The NBM ligand and its ruthenium-bound derivative served as eco-conscious corrosion inhibitors, strategically slowing copper degradation through sustainable chemistry principles. For the corrosion testing phase, concentrated sulfuric acid solution (1 M) served as the primary aggressive environment. Electrochemical impedance spectroscopy and Tafel polarization techniques were employed to examine the corrosion resistance characteristics and suppression efficiency of NBM and its ruthenium-containing derivative within the acidic electrolyte under investigation. Our investigation explored how copper corrosion unfolds within acidic environments, specifically examining how the presence or absence of additives alters this chemical degradation process. “The experimental results reveal a compelling inverse relationship: as additive concentration increases, corrosion inhibition strengthens while the corrosive current density (Icorr) measurably diminishes. It is noted that inhibition efficiency increased and reached 97% and 98.9% in occupying of 1 × 10− 4 and 1 × 10− 6 M of NBM and NBM-Ru additives, respectively. Charge discharge behavior of Cu is also studied in some detail in the absence and presence of additives. Moreover, the investigated compounds were screened for their biological activity against selected strains of bacteria and fungi and found to be more potent against M. Luteus bacteria and C. albicans fungi. Furthermore, Molecular docking was employed to evaluate the binding interactions of the free NBM ligand and its metal complex with the target biomolecule, providing insights into their potential biological activity and comparative affinity.