DFT-Based Analysis of Structure-Activity Relationships of Some Tetrazole Compounds as Corrosion Inhibitors on Carbon Steel in HCl.

Abstract

This study presents a comprehensive quantum chemical analysis of tetrazole (TZ) derivatives as potential inhibitors of iron corrosion in dilute hydrochloric acid (HCl). Investigations were carried out in the presence of. Absence of three compounds: 5-Phenyl Tetrazole, 5-Amino tetrazole and Tetrazole was evaluated in neutral and protonated forms in gas phase and water phase conditions. The thing is, all theoretical calculations were carried out using the density functional theory (DFT) method at the B3LYP/6-311++G(2d,2p) level, which aims to determine the correlation between molecular structure and corrosion inhibitory activity. A complete set of quantum chemical descriptors, including frontier molecular orbital energy, energy gap (ΔE), ionization potential, global hardness, and softness. Electrophilicity index, chemical potential, electronegativity, and Mulliken atomic charge are calculated systematically. Correlation analysis was performed to set up the relationship between these descriptors and the inhibition efficiency of the molecules studied. At the risk of stating the obvious (and this is key), these findings offer valuable molecular-level insights into the adsorption behavior and inhibition mechanisms of tetrazole derivatives on iron surfaces.