Coating Smart Nanolayer of Transition Metal-doped Boron Group with Sulfur-Nitrogen Heterocycles: A Structural-Electromagnetic Analysis by DFT Perspective

Abstract

The surface of the aluminum-titanium-gallium alloy was treated with certain types of carbenes that include sulfur and nitrogen atoms, such as benzotriazole (BTA), 2-mercaptobenzothiazole (2MBT), 8‑hydroxyquinoline (8HQ), and 3-amino-1,2,4-triazole-5-thiol (ATR). NMR spectroscopy indicated that these carbenes can act as sensors when attached to the surface of the titanium-doped aluminum-gallium nanoalloy. In fact, the maximum fluctuation for gallium atoms in the neighboring of titanium in the center of metal alloy (adsorbent) for receiving the electrons of nitrogen (N → Ti), oxygen (O → Ti) and sulfur (S → Ti) of BTA, 2MBT, 8HQ, and ATR heterocycles (adsorbate) was indicated. The presence of nearby aluminum and gallium atoms on the Al₆TiGa₅ or Al(Ti)Ga surface influences how the sulfur and nitrogen atoms in BTA, 2MBT, 8HQ, and ATR link to the surface. NQR analysis showed that the sulfur and nitrogen atoms in the carbenes slow down the movement of the titanium-doped aluminum-gallium nanosheet. The amounts of changes of charge density have exhibited a more important charge transfer from S- and N-heterocyclic inhibitors of BTA, 2MBT, 8HQ, and ATR as the electron donors adsorbed onto Al(Ti)Ga nanoalloy which play a role as the electron acceptor “S → Ti, N → Ti.” When comparing the Gibbs free energy of adsorption (\(\Delta G_{{{\text{ads}}}}^{^\circ }\)) with the dipole moment, there was a good match with the actual measurements. This demonstrates that the chosen model for how the Al(Ti)Ga–BTA, Al(Ti)Ga–2MBT, Al(Ti)Ga–8HQ, and Al(Ti)Ga–ATR complexes form is accurate. Furthermore, the partial electron density or PDOS analysis revealed that there is a transfer of electrons between the Al(Ti)Ga surface and the sulfur and nitrogen atoms in BTA, 2MBT, 8HQ, and ATR. This charge movement shows that the surface has both metallic and covalent properties. This combination increases the sensitivity of the Al(Ti)Ga surface when detecting these carbenes.