DFT calculations of thiosemicarbazide, arylisothiocynates, and 1-aryl-2,5-dithiohydrazodicarbonamides as corrosion inhibitors of copper in an aqueous chloride solution

•The DFT calculation was performed for the first time on these corrosion inhibitors.•The reactivities of these molecules were elucidated from the quantum chemical properties.•Three factors (MPA, MEP, and complex energy) were used to model the adsorption process.

DFT with three functionals was performed on three types of molecules, i.e., thiosemicarbazide, phenylisothiocyanates, and 1-phenyl-2,5-dithiohydrazodicarbonamides used as corrosion inhibitors for copper in chloride solutions. The calculations determined a relationship between the molecular structures and the experimental inhibition efficiencies (%IEs). The order of the experimental %IEs corresponded to the order of most of the calculated quantum chemical parameters (QCPs). Supported by the Mulliken population analysis and molecular electrostatic potential plots, the calculations of the complex energies and the inhibitor-copper bond lengths were used to predict the most active site(s) in the inhibitor to be adsorbed on the copper surface.

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