Theoretical elucidation on the inhibition mechanism of pyridine-pyrazole compound: A Hartree Fock study

The inhibitive effect of three nitrogen-heterocyclic compounds including 3,5-dimethyl-1H-pyrazole (P1), pyridine (P2) and 2-(3-methyl-1H-pyrazol-5-yl) pyridine (P3) against steel corrosion has been studied using ab initio quantum chemical method. It is found that when the organic molecule adsorbs on the steel surface, molecular structure influences its interaction mechanism. P3 has the best inhibition efficiency because of the synergistic effect of pyridine and pyrazole rings. It is also investigated that the inhibition efficiency has certain relationship to highest occupied molecular orbital (HOMO) energy and the combined energy between the inhibitor molecules and the iron atom.