Evaluating the corrosion inhibition properties of novel 1,2,3-triazolyl nucleosides and their synergistic effect with iodide ions against mild steel corrosion in HCl: A combined experimental and computational exploration

• Novel 1,2,3-triazolyl nucleosides are used for corrosion of mild steel in HCl. • The addition of KI to HCl significantly improved the performance of nucleosides. • XPS analysis confirms the adsorption of molecules and iodide ions on mild steel. • DFT, MD and RDF analyses support the adsorption of molecules on iron surface. The search for new effective and eco-friendly corrosion inhibitors seems to be a never-ending task for practical applications. Herein, the principal objective of this work is to investigate the corrosion inhibition effect of novel 1,2,3-triazolyl nucleosides namely, 2-(acetoxymethyl)-5-(3-((1-benzyl-1H-1,2,3-triazol-4-yl)methyl)-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)tetrahydrofuran-3,4-diyl diacetate (TBAc) and 2-(acetoxymethyl)-5-(3-((1-(naphthalen-2-ylmethyl)-1H-1,2,3-triazol-4-yl)methyl)-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)tetrahydrofuran-3,4-diyl diacetate (TNAc) for mild steel (MS) in HCl solution. Different amounts of TBAc and TNAc inhibitors were prepared in 1.0 mol/L HCl medium, and their inhibition effect was investigated via electrochemical measurements, X-ray photoelectron spectroscopy (XPS), quantum chemical calculations (DFT), and molecular dynamics (MD) modeling. Further, we have examined the effect of iodide ions on inhibition efficiency, and the obtained data were compared and discussed. Results showed that these green compounds exhibited high inhibition performances thanks to their excellent molecular and electronic properties. They indicated that TNAc and TBAc showed high corrosion inhibition efficiencies at 5x10 -3 mol/L with 0.1 mmol/L of KI. The inhibition efficiency of TNAc and TBAc reached 85% and 79% at 5x10 -3 mol/L, while it improved to 94% and 91% in the presence of KI, respectively. Electrochemical tests revealed that the studied molecules acted as mixed-type inhibitors and they had a significant effect on the polarization resistance of mild steel. Moreover, the surface morphology analysis was performed using a scanning electron microscope (SEM) and XPS. Besides, a systematic understanding of how these molecules are adsorbed on steel surface was theoretically investigated. Taken together, experimental and theoretical results suggested a significant role of molecular properties of studied derivatives along with intermediate species in promoting their adsorption behavior. A consistent association was found between electrochemical measurements and theoretical calculations.