A Semiempirical PM6 Study of Some Aminopyrimidine Derivatives and their Interaction with an Iron Surface

At present work we analyzed at PM6 level, the electronic properties of 2-aminopirimidyne, 2,4-diaminopirimidyne and 2,4,6-triaminopyrimidine corrosion inhibitors. The results indicated that the HOMO's energy and HOMA index may be related with the inhibition efficiency reported for these compounds. The HOMO's energy values and HOMA indexes indicated that the corrosion inhibition efficiency order is 2,4,6-triaminopyrimidine > 2,4-diaminopirimidyne > 2-aminopirimidyne. The less aromatic compounds showed better corrosion inhibition efficiency. The analysis of the adsorption process of aminopirimidynes on an iron surface indicated that the surface reactivity diminishes in function of the number of amine groups presents in the compound. Thus, the 2,4,6-triaminopyrimidine deactivates the iron surface more efficiently than the 2-aminopirimidyne. Also, it was found that the adsorption process may be done through carbon atoms and not exclusively through Nitrogen atoms.