Designing a Novel Schiff Base and Metal Complexes Derived From Drug Scaffold as Antioxidant Activity and Eco-Conscious Corrosion Inhibitors

The article involves a novel synthesized Schiff base from a pharmaceutical compound, involving the condensation of amoxicillin with 4-(dimethylamino)-2-hydroxy aldehyde in a basic medium. Spectroscopic techniques such as elemental analysis, mass spectrometry, 1H-NMR, FT-IR, and UV-Vis spectrometry were used to characterize the new compound. These methods helped identify the formation of copper (II), silver (I), and gold (III) complexes with the Schiff base ligand (Amox-S). All compounds were evaluated for antioxidant activity using DPPH radical scavenging, showing 71%-86% activity, which was considered good and comparable to the standard ascorbic acid. The corrosion inhibition ability of the Schiff base and its Cu(II) complex on carbon C45 in acidic media (1M hydrochloric acid) was also examined using weight loss measurements at 1x10^-4 - 1x10^-3 M, for varying immersion times (1-10 days) at lab temperature of 25±2^οC to determine the most effective concentration. It was found that the optimal concentration of the ligand and its complex as anti-corrosives was 1x10^-3 M, which significantly enhanced the protective qualities of the coating. This optimal concentration was then evaluated for corrosion protection using polarization methods and the absence and presence of the Schiff base ligand and its copper(II) complex at three temperatures (293, 303, and 313 K). The Amox-S maintained an inhibition efficiency of 91-92% across the temperature range, whereas the Cu-complex exhibited slightly superior performance with IE% values of 93-94%.