Theoretical evaluation of the inhibition properties of two thiophene derivatives on corrosion of carbon steel in acidic media

The density functional theory at the B3LYP/6‐311G++(d,p) basis set level calculations were performed on two thiophene derivatives used as corrosion inhibitors, namely 2‐methylthiophene and 2‐(aminomethyl)thiophene, to investigate the correlation between its molecular structure and the corresponding inhibition efficiency (IE%). Quantum chemical parameters such as the highest occupied molecular orbital energy (EHOMO), the lowest unoccupied molecular orbital energy (ELUMO), energy gap (ΔE), dipole moment (µ), electronegativity (χ), hardness (η), and the fraction of electrons transferred from the inhibitor molecule to the metal surface (ΔN), have been calculated. A good correlation between the theoretical data and the experimental results was found.