Quantum chemical and molecular dynamics simulation studies on inhibition performances of some thiazole and thiadiazole derivatives against corrosion of iron

In the present study, to predict corrosion inhibition performances of 2-amino-4-(4-chlorophenyl)-thiazole (Inh1), 2-amino-4-(4-bromophenyl)-thiazole (Inh2), 4-(2-aminothiazole-4-yl)-phenol (Inh3), 5,5′-(ethane-1, 2-diyldisulfanediyl) bis-(1,3,4-thiadiazole-2-amine) (Inh4), 5,5′-(propane-1,3-diyldisulfanediyl) bis-(1,3,4-thiadiazole-2-amine) (Inh5) against corrosion of Fe metal, density functional theory (DFT) calculations and molecular dynamics simulations approach were performed on these mentioned molecules. Firstly, quantum chemical parameters such as the highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital energy (ELUMO), the energy gap between ELUMO and EHOMO (ΔE), chemical hardness, softness, electronegativity, proton affinity, global electrophilicity, global nucleophilicity and total energy (sum of electronic and zero-point energies) were calculated and discussed with the help of HF/SDD, HF/6-311G, HF/6-31 ++G, B3LYP/SDD, B3LYP/6-311G and B3LYP/6-31 ++G methods. Then, we calculated binding energies on Fe(110) surface of aforementioned thiazole and thiadiazole derivatives to investigate the strength of the interactions between metal surface and these molecules. The theoretical data obtained are in good agreement with the experimental inhibition efficiency results earlier reported.