Theoretical structural study of van der Waals complexes between oxazole and atmospheric gases CO2 and N2 for capture applications.

<ns3:p>Background The objective of this study is to explore the potential of oxazole (C<ns3:sub>3</ns3:sub>H<ns3:sub>3</ns3:sub>NO), a fascinating heterocyclic compound naturally present, which is a potential ligand in the construction of Metal-Organic Frameworks (MOFs) for the selective capture of CO<ns3:sub>2</ns3:sub> in a nitrogen-rich atmosphere, using both molecular and solid-state simulation techniques. Methods This study investigates the equilibrium structures and binding energies of van der Waals aggregates formed by an oxazole molecule with nonpolar molecules such as CO<ns3:sub>2</ns3:sub> and N<ns3:sub>2</ns3:sub>, considering both two-body systems (oxazole@CO<ns3:sub>2</ns3:sub> and oxazole@N<ns3:sub>2</ns3:sub>) and three-body systems (oxazole@CO<ns3:sub>2</ns3:sub>@N<ns3:sub>2</ns3:sub> and oxazole-CO<ns3:sub>2</ns3:sub>/N<ns3:sub>2</ns3:sub>@Au<ns3:sub>6</ns3:sub>/Cu<ns3:sub>6</ns3:sub>/Zn<ns3:sub>3</ns3:sub>O<ns3:sub>3</ns3:sub>). Molecular computations for these systems are conducted using ab initio calculations at the MP2/aug-cc-pVXZ level of theory, where X = (D, T). Additionally, solid-state simulations analyze the adsorption behaviors and energies of oxazole@CO<ns3:sub>2</ns3:sub> and oxazole@N<ns3:sub>2</ns3:sub> on metallic surfaces:Au, Cu and ZnO(111) through Monte Carlo methods. Results We find that the oxazole exhibits more adsorption selectivity for CO<ns3:sub>2</ns3:sub> than for N<ns3:sub>2</ns3:sub>. Adding a second gas to the most stable complexes, oxazole@CO<ns3:sub>2</ns3:sub> and oxazole@N<ns3:sub>2</ns3:sub>, the oxazole capture ability does not vary. On the contrary, it strengthens the adsorption energy of three-body complexes compared to two-body complexes. The addition of metallic clusters (Au<ns3:sub>6</ns3:sub>, Cu<ns3:sub>6</ns3:sub>, Zn<ns3:sub>3</ns3:sub>O<ns3:sub>3</ns3:sub>) and metallic surfaces (Au, Cu, ZnO) enhances the adsorption capacity, where Cu<ns3:sub>6</ns3:sub> is particularly efficient. Both ZnO and Cu surfaces offer significant adsorption advantages while remaining economically feasible. Conclusions This study demonstrates that oxazole exhibits a strong selectivity for CO<ns3:sub>2</ns3:sub> over N<ns3:sub>2</ns3:sub>, with the addition of metallic clusters and surfaces significantly enhancing its adsorption capacity. These findings highlight the potential of oxazole-based materials for effective gas capture and separation, with positive implications for environmental sustainability.</ns3:p>