Sanibel Symposium

Aromaticity remains one of the most fundamental concepts in chemistry. It has extensively been employed to rationalize all types of chemical structures.

However the IUPAC definition of Aromaticity needs to be revised and/or updated (https://goldbook.iupac.org/html/A/A00442.html). It has recently been applied to the family of elemental clusters, that are characterized by their structural richness, unexpected stability and unusual reactivity patterns. Although an elemental cluster inherently differs from an organic or inorganic compound by its electronic structure and bonding, an aromatic character of a cluster can also be established. In this talk, we present some novel aspects of the aromaticity in the boron, silicon, transition metal clusters, having different geometrical shapes including the ribbon, the circular disk, the bowl, the cube, the hollow cylinder, the fullerene-type, the bucky balls… These multiple aromatic characters can be regarded, for the time being, as non-classical as they do not follow the conventional electron counting rules (such as the Hückel rule). The electronic structure of these aromatic clusters can be predicted by simple electron models.