Preparation of Nano-Metal Complex of Benzilic Acid and Its Corrosion Inhibition & Biological Study

Benzilic acid and its derivatives are versatile ligands that form stable metal complexes with potential applications in materials science and biomedical fields. This study reports the synthesis of benzilic acid-derived nano-metal complexes, their physicochemical characterization, evaluation as corrosion inhibitors for mild steel in acidic media, and preliminary biological activity (antimicrobial and antioxidant) assessment. Nanosizing was achieved using a green-assisted co-precipitation/sonochemical approach (ultrasonication in the presence of a stabilizer) to yield nano-metal complexes (NMCs). The materials were characterized by FT-IR, UV–Vis, XRD, TEM/SEM, and DLS for particle size, morphology, and coordination mode confirmation. Corrosion protection of mild steel was evaluated in 1.0 M HCl using weight-loss measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). Inhibitor performance was studied across a concentration range and at different immersion times and temperatures Antimicrobial activity was screened against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) strains using disk diffusion and minimum inhibitory concentration (MIC) assays. The synthesized NMCs exhibited nanoscale dimensions (confirmed by TEM/XRD), strong coordination of the ligand to the metal center (FT-IR/UV–Vis), and improved corrosion inhibition compared with the free ligand: inhibition efficiency increased with concentration and adsorption followed predominantly Preliminary biological screening showed measurable antimicrobial activity (greater effect on Gram-positive strain in our samples. These materials could be further optimized for industrial corrosion control and biomedical coatings after in-depth toxicological and long-term performance studies.