Three‐Dimensional Aromaticity

When chemists come across the term aromatic , most of them think of benzene and hetero or polycyclic aromatic derivatives. These organic compounds are generally planar with a closed two-dimensional circuit for electron delocalization leading to what is considered aromaticity in two dimensions. In the last decades, the boundaries of aromaticity have been extended to a large list of diverse species, comprising molecules forming closed three-dimensional circuits, like charged fullerenes or closo borane clusters. In this sense, new types of aromaticity have been described, including spherical, cubic, octahedral, tetrahedral, or cylindrical aromaticity. In this chapter, these different types of three-dimensional aromaticity are reviewed.