Adsorption of explosive and hazardous compounds by cyclo[10]carbon and cyclo[14]carbon: A DFT study

The adsorption and detection of explosive and hazardous compounds are highly important for preventing accidents. In this study, two new synthesized cyclo[n]carbons (n = 10, C₁₀. n = 14, C₁₄) were employed as new sensors to adsorb six explosive (N₃H, NH₂NO₂) or hazardous compounds (CO, HCHO, HCN, NH₃). Based on the DFT calculations, first of all, it is found that all six adsorbates are adsorbed inside the conjugated ring of of C₁₀ and C₁₄ with the adsorption energies ranged from 15.7 to 38.9 kJ/mol, showing the typical weak-to-moderate physical adsorption characteristic. Then, C₁₄ indicated the stronger adsorption toward six small molecules than C₁₀ in general. And, both C₁₀ and C₁₄ showed the best selectivity toward the adsorption of NH₂NO₂ than others. Plus, the adsorption mechanisms to the same adsorbate are different sometimes for two cyclo[n]carbons, due to the difference in the shape, size, and type of chemical bonds of them. Finally, the short recovery time ranged from 8.7 fs to 0.024 ms, and significant changes in the spectrum also supports the high potential for using C₁₀ and C₁₄ as sensors for adsorbing and detecting these six explosive or hazardous compounds. METHODS: All of the calculations on the structures were carried out by using the Gaussian 09 software at the M06-2X/6-311G(d,p), M06-2X-D3/6-311G(d,p), and M06-2X-D3/6-311++G(d,p) level. In addition, further calculations on the properties and interactions were performed by using the Multiwfn software.