Adsorption of novel heterocyclic compounds of the purine derivatives as corrosion inhibitors over mild steel surface in acidic medium: Electrochemical, surface characterization and theoretical investigations

In the current study, the adsorption of two new heterocyclic purine derivative compounds is investigated. namely, 7H-purin-6-amine (Adenine) (M2) and 7H-purin-6-amine (Adenine) (2R,3R,4S,5R) -2-(6-amino-9H- purin-9-yl)-5-(hydroxymethyl) tetrahydrofuran-3,4-diol (M3) against the corrosion of mild steel in 1.0 M HCl medium. Weight Loss (WL), Electrochemical Impedance Spectroscopy (EIS), and Potentiodynamic Polarization (PDP) were among the techniques used in the experimental investigation. The respective inhibition efficiencies of M2 and M3 were found to be 89.0% and 96.5%.The Langmuir adsorption model was used to describe how M2 and M3 adsorb on the mild steel substrate. In addition, SEM/EDS, AFM, XRD, contact angle, and FT-IR techniques were employed to analyze the surfaces to support a protective film over the metal surface. Inductively coupled spectroscopy (ICP) was used to examine the WL observations as well. Furthermore, Molecular Dynamics (MD) simulations and DFT calculations were conducted to analyze the interaction of M2 and M3 with the mild steel substrate and their manner of adsorption.