Local Aromaticity: An Important Indicator of the Surface Active Sites of Heterocyclic Nanostructures

Quick identification of the active sites on the surfaces of nanomaterials is rather critical for disclosing their exact interaction mechanism with various adsorbates in the general adsorption and catalysis processes. In this work, we propose that the local aromaticity of the surface sites (bonds or atoms) of different heterocyclic nanostructures (fullerenes, nanotubes, and nanosheets) could be easily evaluated by averaging the nucleus-independent chemical shifts at the centers of the surrounding rings. Significantly, almost all the sites exhibiting the weakest aromaticity or the strongest antiaromaticity are optimal active sites for adsorbing common small molecules. The underlying driving force is further clarified to be the maximum preservation of the global aromaticity of the system.