Faculty of Technology, University of El Oued, Algeria.
Abstract
Quantum chemical calculations and molecular dynamics simulations were performed to investigate the effect of four flavonoids compounds (Kaempferol, Quercetin, Myricetin and Rhamnetin) from Guiera Senegalensis leaves on corrosion inhibition of aluminium metal in vapour phase. Quantum chemical parameters including EHOMO, ELUMO, energy gap (ΔE), electronegativity (χ), global hardness (η), global softness (σ) and fraction of electrons transferred (ΔN) from the flavonoid molecule to the aluminium surface were calculated and the results indicate that the larger the molecular size the better the inhibition efficiency. Local reactive sites through Fukui indices were also calculated to explain the effect of electronic and structural features of the flavonoid compounds present in the leaves extract of Guiera senegalensis (GS). The results showed that the point of interaction of inhibitor molecule with the Al(1 1 0) surface were through hydroxyl and carbonyl functional groups of the studied compounds. Molecular dynamic simulations revealed that the adsorption behaviour of each flavonoid molecule on Al(1 1 0) surface through quench dynamics were found to obey the mechanism of physical adsorption and the more negative is the adsorption energy between the inhibitor-metal surface the better inhibition performance of the molecule on Al(1 1 0) surface.
 
