Corrosion inhibition modeling of some benzenethiol derivatives on copper using quantum chemical descriptors

In this work, two quantum mechanical descriptors were proposed for quantitative structure-inhibition relationship (QSIR) study of copper corrosion in sulfuric acid media. These descriptors were chosen based on inhibition mechanism of some benzenethiol derivatives on copper corrosion. The first descriptor was adsorption energy of inhibitor compounds on copper cluster (Eads) and the second was excretion energy of H3O+ ion by copper-inhibitor complex system (Eexc). The results obtained indicate that the calculated descriptors can well explain various aspects of the protection imposed by the inhibitor molecules, so that more than 90.4% of the inhibition imposed on metallic copper is illustrated. In addition, validation analysis of the derived model indicate that the applied descriptors have significant effect on interpreting the protection process. On the other hand, the generated model by the most common quantum mechanical descriptors (Ehomo , Elumo, Gap, µ) can only describe 69.1% of experimental inhibition of the inhibitor molecules which clearly show effectiveness of the proposed descriptors.