The use of computational chemistry as an effective means of designing eco-friendly organic corrosion inhibitors has been greatly enhanced by the development of Density Functional Theory (DFT). In this study, the inhibitory activity of four antiretroviral drugs, namely, lamivudine, emtricitabine, didanosine and stavudine, was analyzed by this theory. The quantum chemical parameters/descriptors calculated using DFT at B3LYP/6-31G(d) level were used to explain the mechanism of electron transfer between the inhibitors and the copper surface. The results showed that these compounds adsorb on copper surface. It is important to consider the effect of films formed by the adsorption products. In addition, the Fukui functions and the dual descriptor were used as indicators to locate the electrophilic and nucleophilic attack sites within each compound. Finally, the DFT has enabled to accurately predict the adsorption properties and the good inhibition performance of the molecules in the solution studied.

The theoretical study of chlorpropamide, tolazamide and glipizide was carried out by the Density Functional Theory (DFT) at B3LYP/6-31G(d) level. This study made it possible to determine the global reactivity parameters in order to better understand the interactions between the molecules studied and the copper surface. Then, the determination of local reactivity indices (Fukui functions and dual descriptor) on these molecules resulted in the precision on the most probable centers of nucleophilic and electrophilic attacks within each molecule. The results obtained, show that chloropropamide, tolazamide and glipizide can be good inhibitors against copper corrosion. Thus, the mechanism of copper corrosion inhibition of these compounds in nitric acid solution has been explained by means of theoretical calculations.

The metal corrosion threat in the metallurgical industry is becoming increasingly important. So in this work, the inhibition properties of 2-(1,3-dihydrobenzimidazol-2-ylidene)-3-oxo-3-(pyridin-3-yl) propanenitrile for copper corrosion in 1 M nitric acid medium were evaluated by mass loss technique, density functional theory (DFT) and quantitative structure-property relationship (QSPR) model. The results show that this compound was excellent anticorrosive properties with a maximum inhibition efficiency of 89.39 % for a concentration of 0.2 mM at 323 K. The inhibition efficiency increases with increasing temperature and inhibitor concentration. Adsorption isotherms reported that the molecule adsorbs on copper surface according to Langmuir isotherm. Thermodynamic adsorption and activation parameters were determined and analyzed. They revealed spontaneous adsorption and a strong interaction between the molecule and copper surface. DFT calculations at the B3LYP level with 6-31G(d,p) and 6-311G(d,p) basis set permitted to explain the electronic exchanges between molecule and copper, thus justifying the experimentally obtained inhibition efficiency values. A local reactivity study of molecules indicated that N (29) and C (7) atoms are the likely sites for nucleophilic and electrophilic attacks, respectively. In addition, QSPR model was used to correlate experimental inhibition efficiency with the descriptor parameters of the studied molecule, and it is found that the calculated inhibition efficiencies are close to experimental inhibition efficiencies. Finally, this study showed a good correlation between theoretical and experimental data.

The present study was designed to determine the inhibition effect of 2-(1H-benzimidazol-2-yl)-3-(4-hydroxyphenyl) acrylonitrile in 1M HNO3 using a combined experimental and theoretical approach. Mass loss techniques revealed that 2-(1H-benzimidazol-2-yl)-3-(4-hydroxyphenyl) acrylonitrile inhibition efficiency is dependent on its concentration and temperature. It has been shown that the studied molecule inhibits copper corrosion by an adsorption behavior by donating and accepting electrons. Kinetic parameters have been determined and discussed. Quantum chemical parameters calculated by means of density functional theory (DFT) have shown that studied molecule reactivity is strongly related to the electronic properties, which could help to understand the molecule-metal interactions. The reactive sites have been determined by means of Fukui Functions and dual descriptor. Quantitative structure-property relationship (QSPR) model introduced in this study was used to find a set of quantum chemical parameters capable of correlating the experimental and theoretical data in order to design more suitable organic corrosion inhibitors. The theoretically obtained results were found to be consistent with the experimental data reported.

Inhibition corrosion of metals by using organic compounds has become an unavoidable means. So, in this work, the effect of methylxanthines on copper corrosion inhibition in 1M HNO3 was investigated by mass loss measurements and by two theoretical approaches: Density Functional Theory (DFT) and Quantitative Structure Property Relationship (QSPR.) Quantum chemical calculations based on DFT at the B3LYP/6-31G(d) level permit to establish a correlation between the quantum chemical parameters and the experimental inhibition efficiency (IE %). It was found that inhibition efficiencies increase with increasing temperature and immersion time. In addition, the QSPR approach was used to find the best set of parameters for each molecule. This set of parameters make it possible to characterize the inhibition performance of the tested molecules solution significantly. The theoretical calculations are consistent with the experimental results.