quinazoline derivatives as corrosion inhibitors on aluminium metal surface: a theoretical study

Quantum chemical calculations and molecular dynamics simulation techniques were used to assess the corrosion inhibition potential of the compound qiunazoline (qzn) and two of its derivatives, 6-chloro-4-imino-3-phenyl-3,4-dihydro-1h qiunazoline-2-thione (qzt) and 6-chloro-4-imino-3-phenyl-3,4-dihydro-1h qiunazoline-2-one (qzo). the values of the quantum chemical parameters ehomo, elumo, energy gap (δe), the energy of back donation (δeb-d), dipole moment (μ), electronegativity (χ), global hardness (η), global electrophilicity index (ω), nucleophilicity (ε) and others were determined. the quantum chemical parameters calculated revealed that qzo is relatively more nucleophilic in nature and potentially a better inhibitor. the fukui indices values discovered that the hetero atoms (n, o and s) of the studied compounds are responsible for their inhibitive characteristics. according to the calculated binding and adsorption energies obtained from the quenched molecular dynamic simulations, the relatively low values obtained of less than 100 kcal/mol results in the molecules being weakly adsorbed onto the surface of al(1 1 0) through van der waals forces and consequently obey the physical adsorption mechanism in the order: qzo>qzt> qzn. the examined molecules' varied bond lengths and angles before and after adsorption on the al(1 1 0) surface demonstrate the nature of adsorption and the molecules' non-planarity on the surface of the metal. qzo and qzt have larger molecular sizes and additional hetero atoms (o and s), making them possibly more corrosion-inhibitive on al(1 1 0) surfaces than qzn.