Density Functional Theory and Quantitative Structure-Activity Relationship Studies of some Quinoxaline derivatives as potential Corrosion Inhibitors for Copper in Acidic Medium

摘要

Density Functional Theory (DFT) using the B3LYP functional and Quantitative Structure-ActivityRelationship QSAR studies is reported on some quinoxaline derivatives namely 3-methyl-2-phenylquinoxaline (MPQ), 2,3-diphenyl quinoxaline (PPQ), 3-methyl-2(2-hydroxyphenyl)quinoxaline(MHPQ), 3-phenyl-2(2-hydroxyphenyl)quinoxaline (PHPQ) and 3-methyl-2(3-methoxy,4- hydroxyphenyl)quinoxaline (MMtHPQ) used as corrosion inhibitors for copper in acidic medium. DFTwas utilized to model the quinoxaline楋儣桟u interaction mechanism in order to obtain molecularreactivity parameters (for elucidating the reactivity tendency for each of the studied quinoxalinederivative). Some of the reactivity parameters were correlated with the experimentally determinedinhibition efficiencies using quantitative structure activity relationship (QSAR). The results show thatan optimum of three quantum chemical parameters is sufficient to correlate with experimentallydetermined inhibition efficiencies. The quinoxaline楋儣桟u interaction shows that the Cu atom binds tothe quinoxaline derivatives with the preferred geometries corresponding to cases in which the Cu atomis in a multi-dentate mode or geometry.