Molecular modelling framework of metal-organic clusters for conserving surfaces: Langmuir sorption through the TD-DFT/ONIOM approach

Abstract

The Langmuir adsorption model of some organic inhibitors containing benzotriazole (BTA), 8- hydroxyquinoline (8-HQ), and 2-mercaptobenzothiazole (2-MBT) onto the Al-X (X=Mg, Ga, Si) alloy surface.The ONIOM method has been accomplished with a three-layered step of high level of DFT method using EPR-III, 6-31+G (d,p) and LANL2DZ basis sets. NMR spectroscopy has indeed concentrated on the Al shielding in the intra-atomic interaction with Mg, Ga and Si and meanwhile interatomic interaction with other atoms in BTA, 8-HQ, and 2-MBT compounds. Aluminum-silicon binary alloy with highest changes in the shielding tensors of NMR spectrum produced by intra-atomic interaction directs us to the most penetration in the neighbor atoms created by interatomic reaction. IR computations based on comparing the amounts has exhibited that 2-MBT with high stability based on its active zone of sulfur atoms and high molecular size shows high corrosive inhibition as 2-MBT →Al-Ga>Al-Mg ≈ Al-Si. Furthermore, BTA with nitrogen atom and 8-HQ with oxygen atom can coat the Al-X (X=Mg/Ga/Si) alloys surface through Langmuir adsorption as BTA →Al-Ga>Al-Mg ≈ Al-Si, and 8-HQ →Al-Ga>Al-Mg ≈ Al-Si, respectively. Moreover, it has been observed that the inhibition yield is ordered as: Al-Ga> Al-Mg ≈ Al-Si.