Experimental and theoretical evaluation of the anticorrosive proprieties of new 1,2,3-triazolyl-acridine derivatives
Caio Machado Fernandes, Renato Lessa, Dora C. S. Costa, Lucas Soares de Souza Pinto Guedes, Vinicius Martins, Awad A. Alrashdi, Vı́tor F. Ferreira, Fernando de Carvalho da Silva, Júlio César M. Silva, Marcela Cristina de Moraes, Hassane Lgaz, Eduardo A. Ponzio
Abstract
Three novel 1,2,3-triazolyl-acridine derivatives (abbreviated as TTA, ATM, and ATA) were synthesized via a fast ultrasound-assisted copper-catalyzed azide-alkyne cycloaddition (CuAAC) in good yields. They were studied as corrosion inhibitors for 1020 mild steel in acidic media (1 mol L-1 HCl) using gravimetric and electrochemical measurements. Weight Loss Study showed that those molecules have anticorrosive efficiency varying from 85 to 94% at 1 mmol L-1 (298 K). They also increased their corrosion mitigation at higher temperatures, reaching up to 90-96% at 338 K. Isotherm fitting revealed that all developed corrosion inhibitors follow the Langmuir theory and data crossing confirmed the monolayer formation. Atomic Force Microscopy suggested the presence of a protective film on the metal surface and Electrochemical Impedance Spectroscopy, Linear Polarization Resistance, and Electrochemical Frequency Modulation showed a better charge transfer and polarization resistance alongside a lower corrosion current density in the presence of TTA, ATM, and ATA in the corrosive media. Also, polarization curves characterized all three organic molecules as mixed-type corrosion inhibitors for mild steel. First-principles density functional theory (DFT) simulations revealed that all molecules form covalent bonds with iron atoms upon adsorption on Fe(110) surface. The ATA molecule exhibited a bond-breaking upon adsorption and had a higher interaction energy with the iron surface. The chemical interactions between inhibitors’ molecules and iron atoms were confirmed by projected density of states analysis, showing a strong hybridization between molecules’ orbitals and 3d iron orbitals.