Molecular structure and mild steel/HCl corrosion inhibition of 4,5-Dicyanoimidazole: Vibrational, electrochemical and quantum mechanical calculations
By Abuelela, Ahmed M.; Bedair, Mahmoud A.; Zoghaib, Wajdi M.; Wilson, Lee D.; Mohamed, Tarek A.
Published in Journal of Molecular Structure
Journal of Molecular Structure
2020
Abstract
Raman (3500-50 cm?1) and FT-ATR/FT-infrared (3500-500/4000-200 cm?1) spectrum of 4,5-Dicyanoimidazole (DCI) were recorded and analyzed by normal coordinate analysis calculations. In addition, we have studied the molecular structure of DCI by means of B3LYP Density Functional Theory (DFT) using 6-31g(d) basis set. Aided by computational outcomes, all vibrational bands were assigned quantitatively to their corresponding fundamentals. The corrosion inhibition efficiency of DCI towards mild steel in 1.0 M HCl has been investigated experimentally and theoretically. Electrochemical impedance spectroscopy, electrochemical frequency modulation and polarization measurements along with thermodynamic predictions were assigned to both the anodic and cathodic inhibition. DCI-metal interactions and charge reallocation were analyzed in terms of Frontier molecular orbital (FMO) and Natural bond orbital (NBO) analysis. Global reactivity descriptors; ionization potential (IP), electron affinity (A), electronegativity (?), chemical potential (