Molecular Dynamics and Density Functional Theory Study on Corrosion Inhibitory Action of Three Substituted Pyrazine Derivatives on Steel Surface

A theoretical study for three derivatives of pyrazine namely 2-methylpyrazine (MP), 2aminopyrazine (AP) and 2-amino-5-bromopyrazine (ABP), which are recently used as corrosion inhibitors for steel in 1.0 M H2SO4 medium, was undertaken by Density Functional Theory (DFT) at the B3LYP level. Their properties are most relevant to their potential action as corrosion inhibitor and have been calculated by EHOMO, ELUMO, energy gap (ΔE), dipole-moment (μ), electronegativity (χ), global hardness (η) and fraction of electron transferred from the inhibitor molecule to the metallic atom (ΔN). To explain their inhibition performance, local reactivity of the molecule has been analyzed through Fukui function. Furthermore, the binding energies of the inhibitors with the Fe (0 0 1) surface are studied using Molecular Dynamics (MD) simulation method. The theoretical results are in well accordance with the recently reported experimental outcomes.