A new cluster model based descriptor for structure-inhibition relationships: A study of the effects of benzimidazole, aniline and their derivatives on iron corrosion

Interaction energies of benzimidazole, aniline and nine of their derivatives on the surface of iron are calculated in hydrochloric acid medium via cluster model by using quantum chemical calculations at DFT level. The interaction energy is then used as a descriptor in a QSIR method for corrosion behavior modeling of the inhibitors in solutions at different concentrations. It is shown that, a combination of interaction energy and three descriptors related to polarizability, electronegativity and 3D structure of inhibitor molecules can excellently describe the corrosion inhibition on iron. The findings are indicative of the effectiveness of the new descriptor.

► Inhibition behavior of a series of compounds on iron in HCl is modeled.
► Cluster model based interaction energy is considered as a new descriptor.
► Cluster model and QSIR methods are complementary in describing inhibition.
► The new descriptor is superior to HOMO, LUMO, gap and dipole moment.
► An interpretable model is established for corrosion inhibition efficiency.