Evaluation of corrosion inhibition efficiency of some novel schiff bases through a proposed qsar model: Dft investigations supported by weight loss technique

Abstract

Organic molecules having some functional groups, double and triple bonds in their structures have high capabilities in preventing and inhibiting metal corrosion in various corrosive solutions. The conventional Quantitative Structure Activity Relationship (QSAR), is known as a worthwhile model to foretell corrosion inhibition efficiency. In some cases, the results obtained from the conventional QSAR model are significantly different from laboratory values. The corrosion inhibition efficiency of a novel Schiff base namely (E)-N1-(thiophen-2-ylmethylene)-N3,N3-bis(2-((E)-(thiophen-2-ylmethylene)amino)ethyl)propane-1,3-diamine with its derivatives were studied using density functional theory (DFT) calculations and QSAR approach. The quantum chemical parameters including the energies of the molecular orbital, the highest occupied molecular orbital, the lowest unoccupied molecular orbital and dipole moment were calculated to investigate the inhibition efficiency of inhibitors. The results showed that this compound and its derivatives have high corrosion inhibition efficiency especially at high concentrations. Noticeable correlation was obtained between corrosion inhibition efficiency and quantum chemical parameters through B3LYP/6-31G** method. The obtained theoretical results were in good agreement with the experimental findings. Moreover, we proposed a modified QSAR (MQSAR) model and evaluated it by our novel Schiff bases as well as some derivatives of triazole, oxadiazole and thiadiazole. The results obtained through MQSAR were in a better agreement with experimental inhibition efficiency values.