A Tricyclic Aromatic Isomer of Hexasilabenzene

Abstract

Aromatic Silicon: Benzene has long intrigued chemists on account of the energy stabilization, termed aromaticity, which arises from π-electron delocalization around its ring framework. A persistent question has been how such stabilization would be impacted were the carbons to be replaced by heavier atoms such as silicon. Abersfelder et al. (p. 564 ) have prepared a benzene analog with Si atoms in place of all six-ring carbons, but a slightly altered bonding framework in which substituents outside the ring are no longer evenly distributed. Instead, the substituents pair up at two Si sites, leaving two other ring sites with no external appendages. The resulting compound no longer has a continuous network of π-electrons, but retains a degree of aromatic stabilization involving sigma and nonbonding electrons.