Trends of inhibiting corrosion by HU1 and HU2 were explored with the use of the theory of density functional (DFT) at the B3LYP/6-311 + G(d,p) level of theory. The quantum chemical descriptors calculated for the two compounds or chemical parameters were correlated with its corrosion inhibition efficiency. The molecular descriptors have been analyzed through the function of Fukui and soft local indices, to compare the possible sites of electrophilic and Nucleophilic attack. The success of the calculation of the DFT in the prediction of the efficacy of inhibition is reported to be satisfactory, and the result reveals that HU2 with the energy of adsorption of-91.38 is greater than the HU1, that is-394.42 kJ/mol. The deformation energy of the inhibitor HU1 and HU2 was reported as -307.11 and 8.05 kJ/mol respectively, suggesting that the interaction between HU2 and the metal surface is more stable and would require an additional energy to dissociate their interaction.
Keywords: Iron; Adsorption; Corrosion; DFT method; Fukui Function; phenyl-urea.