On the efficiency of barbituric acid and its thio derivatives as aluminium corrosion inhibitors: A computational study

[Display omitted] •Corrosion inhibition efficiency of barbituric acid and its thio derivatives toward aluminium surface is elucidated.•Molecular dynamics simulations are executed for inhibitor∙∙∙aluminium (Al)(111) complexes.•Binding energy affirmations proclaim increasing the inhibition efficiency in the order BA∙∙∙ < 1S∙∙∙ < 2S∙∙∙ < 3S∙∙∙Al.•Global and local reactivity parameters affirm the further favorability of 3S compound over other studied analogs. The corrosion inhibition efficiency of the barbituric acid and its thio derivatives were herein monitored by the execution of a variety of density functional theory (DFT) computations. The 1,3-diazinane-2,4,6-trione (BA); 6-sulfanylidene-1,3-diazinane-2,4-dione (1S); 2,6-bis(sulfanylidene)-1,3-diazinan-4-one (2S); and 1,3-diazinane-2,4,6-trithione (3S) compounds were devoted as aluminum corrosion inhibitors. Global and local quantum descriptors were determined for the neutral and protonated forms of the modelled inhibitors in gas and aqueous phases. As the global indices indicated, reverse and proportional correlations were noticed between the number of S atoms in the studied inhibitors and their ionization potential and electron affinity. Accordingly, the inhibition efficiency of the studied compounds generally increased in the order BA