Regio- and chemoselective synthesis of new isoxazolyl-linked benzimidazolones via 1,3-dipolar cycloaddition: Characterization, corrosion studies, density functional theory, and Monte Carlo simulations

Abstract

In this study, novel compounds, isoxazolyl-benzimidazolone (AE1) and isoxazolinylbenzimidazolone (AE2), were synthesized and characterized using various spectroscopic methods. This involved employing 1,3-dipolar cycloaddition techniques with 2,4,6-trimethoxylbenzonitrile N-oxide and mesitonitrile-oxide in combination with “1-cyclohex-1-en-1-yl-3-propargyl-benzimidazolone” or “1-cyclohex-1-en-1-yl-3-allylbenzimidazolone”. The structural identification of these newly formed cycloadducts was achieved through comprehensive analytical and spectral analyses. The two heterocyclic compounds, AE1 and 2, have been investigated into their corrosion inhibition potential of mild steel (MS) in 1.0 M HCl, utilizing diverse analysis methods such as Potentiodynamic Polarization (PDP), Electrochemical Impedance Spectroscopy (EIS), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray (EDX) techniques. The outcomes revealed significant corrosion inhibition, with AE1 displaying the highest effectiveness (97.2 %), followed closely by AE2 (95.8 %) at 10−4M. The inhibitors were observed to adhere to the MS surface following Langmuir isotherms, and their adsorption and thermodynamic characteristics were thoroughly assessed. Moreover, Density Functional Theory (DFT) and Monte Carlo (MC) simulations corroborated the robust adsorption capability of these organic chemicals on the MS surface.