A comparative density functional theory and molecular dynamics simulation studies of the corrosion inhibitory action of two novel N-heterocyclic organic compounds along with a few others over steel surface

Four novel pyrazine derivatives namely 2-aminopyrazine (AP), 2-amino-5-bromopyrazine (ABP), 3-amino pyrazine-2-thiol (APT) and 3-amino-6-bromopyrazine-2-thiol (ABPT) are investigated for their possible utilization as corrosion inhibitors by computational chemistry using density functional theory (DFT) and molecular dynamics (MD) simulation. Organic molecules (AP and ABP) along with two other similar organic framework (APT and ABPT) having an additional -SH group have been thoroughly investigated as corrosion inhibitors by means of theoretical investigation (DFT and MD simulation) with a vision that they can perform better. Their corrosion inhibition property have been calculated by several energy parameters like EHOMO, ELUMO, energy gap (ΔE), electronegativity (χ), softness (S) and fraction of electron transferred from inhibitor molecule to metallic atom (ΔN). Local reactivity of these molecules has been studied through Fukui indices. Significantly, DFT and MD simulation results are in well agreement with experimental outcomes for AP and ABP. Moreover the theoretical results show that -SH based pyrazine derivatives i.e.; APT and ABPT, are even better potential candidate as corrosion resistant. Theoretical outcome reflects that introduction of -SH group will result betterment towards inhibition property.