Quantum Mechanical Study of Some 2-Mercaptobenzimidazole Derivatives as Corrosion Inhibitors for Carbon/Mild Steel in Acidic Medium

In this work some of 2-mercaptobenzimidazole derivatives have been theoretically studied to prove their ability as corrosion inhibitors; Gaussian 09W program packages and its visualization interface program GaussView 5.0 have been used. Density Functional Theory (DFT) with basis set of 6-311G (d,p) / hybrid function of B3LYP has been used in all calculations. This work included simulation of these derivatives in three different mediums; gas phase, aqueous and acidic medium. Some parameters have been calculated such EHOMO, ELUMO, ΔELH, Electron Affinity (A), Ionization Potential (I), electronegativity (χ), Global Hardness (η), Total Negative Charges TNC, Dipole Moment (μ) and Fraction of Electron Transferred from Inhibitor Molecules to the Metallic Atoms (ΔN), all these parameters proved behaviors of these compounds as corrosion inhibitors for carbon steel, so these derivatives can be considered as corrosion inhibitors.