Theoretical and electrochemical assessment of inhibitive behavior of some thiophenol derivatives on mild steel in HCl

► Two synthesized organic compounds were experimentally and theoretically investigated. ► All investigated compounds showed physisorption on the surface. ► Trail of inhibitor efficiency with immersion time. ► Employing Gaussian DFT method for quantum chemical study of inhibitors. Inhibitive performance of some synthesized thiophenol derivatives on corrosion behavior of mild steel in 0.1 M HCl solution was investigated by means of electrochemical techniques, quantum chemical and optical microscopy. The increase in concentration and immersion time shows a positive effect on inhibition efficiency while temperature has a negative effect. Inhibitor molecules directly adsorb at surface on the basis of donor–acceptor interactions between the π-electrons of benzene, sulfur and nitrogen atoms and the vacant d-orbitals of iron atoms. According to the thermodynamic parameters, present inhibitors adsorb physically. Optical microscopy examinations demonstrate a decrease in corrosion attacks in presence of inhibitors.