It is known that iron is one of the most widely used metals in industrial production. In this work, the inhibition performances of three thiophene derivatives on the corrosion of iron were investigated in the light of several theoretical approaches. In the section including DFT calculations, several global reactivity descriptors such as E_HOMO, E_LUMO, ionization energy (I), electron affinity (A), HOMO-LUMO energy gap (ΔE), chemical hardness (η), softness (σ), as well as local reactivity descriptors like Fukui indices, local softness, and local electrophilicity were considered and discussed. The adsorption behaviors of considered thiophene derivatives on Fe(110) surface were investigated using molecular dynamics simulation approach. To determine the most active corrosion inhibitor among studied thiophene derivatives, we used the principle component analysis (PCA) and agglomerative hierarchical cluster analysis (AHCA). Accordingly, all data obtained using various theoretical calculation techniques are consistent with experiments.

The adsorption and corrosion inhibition properties of some benzotriazole and phospono derivatives namely, 1-(2-pyrrolecarbonyl)-benzotriazole (PBTA), 1-(2-thienylcarbonyl)-benzotriazole (TBTA), 2-phosphonoacetic acid (PAA) and 4-phosphonobutyric acid (PBA) on the corrosion of aluminum were investigated by quantum chemical calculations and by molecular dynamics simulations. Global reactivity descriptors such as E_HOMO, E_LUMO, HOMO–LUMO energy gap (ΔE), chemical hardness (η), softness (σ), electronegativity (χ), proton affinity (PA), electrophilicity (ω) and nucleophilicity (ε) have been calculated and discussed. The analysis of the adsorption behavior of these mentioned inhibitors on the Al (111) surface was investigated using molecular dynamics simulations. The binding energies on the Al (111) surface of the studied compounds followed the order: PBTA > TBTA > PBA > PAA. The results obtained in this study are compatible with experimental data and it is proposed that the above mentioned molecules can be successfully used to prevent the corrosion of aluminum metal.