Investigation of 5,5′-(Pyridine- 2,6-diyl)bis(4-phenyl-4H-1,2,4-triazole-3-thiol) as corrosion inhibitors for mild steel in acidic media

The correlation between the quantum chemical parameters and inhibition efficiency using quantitative structure activity relationship (QSAR) of of 5,5′-(Pyridine-2,6-diyl)bis(4-phenyl-4H-1,2,4-triazole-3-thiol)was investigated using DFT/B3LYP calculations. The inhibition efficiency of the inhibitor are closely related to the quantum chemical parameters, the highest occupied molecular orbital (EHOMO), energy of lowest unoccupied molecular orbital (ELUMO), HOMO–LUMO energy gap (ΔEH-L), the hardness (σ), the softness (η) and the fraction of electrons transferred (ΔN) for the neutral inhibitors and no significant relationship was found with parameters, dipole moment (μ) and the total energy (TE).