Quantum Chemical Investigation of the Relationship Between Molecular Structure and Corrosion Inhibition Efficiency of Benzotriazole and its Alkyl-Derivatives on Iron

In this study, we have investigated possible role as iron corrosion inhibitor of four benzotriazole derivatives, BTA, BTA-C1, BTA-C4, BTA-C6, using DFT calculations at B3LYP/6-311G^** level of theory. For this purpose, we have determined some structural and electronic parameters such as HOMO and LUMO orbital energies, energy gap, electron affinity, ionization potential, hardness, softness, absolute electronegativity, chemical potential, electrophilicity index, fractions of electrons transferred and back donation, logP, molecular surface area, polar surface area, molecular volume, molar refractivity and have compared with experimental literature results. We have also computed and discussed the interaction energy of the inhibitors with iron surface. The calculated parameters are closely related to the inhibition efficiencies, and have compared with experimental literature values using linear regression analysis to determine the most effective parameters on inhibition efficiency.