Investigation of the effect of halide counterions on the potential corrosion inhibitor in imidazolium-based ionic liquids

Imidazolium (IMZ)-based ionic liquids (ILs) with various counter ions were investigated as potential corrosion inhibitors. Furthermore, parameters such as bond lengths, bond angles, and dihedral bonds were investigated to demonstrate the adsorption sites of molecules. Moreover, in order to compare the efficiency of the inhibitors, other parameters such as energy gap, hardness, the LUMO, and the HOMO were investigated. The HOMO and LUMO values increased from −4.370 and −0.106 eV to −4.959 and −0.156 eV, respectively, by changing F⁻ to I⁻. Moreover, the softness of the IMZ base changed from 0.469 to 0.417 eV by increasing the radius of the halide ion. The trend of the band gap value in going from F⁻ to I⁻ changes from 4.264 to 4.797 eV. The total electron density was computed to show the adsorption sites based on the electron density. According to the molecular reactivity results, the inhibitory efficiency of the inhibitors was in the following order: BMI-F > BMI-Cl > BMI-Br > BMI-I. Investigating the IMZ-based ILs with various counterions to evaluate the inhibition profile of molecules provides useful insights into computational protocols for the study of corrosion inhibitors.