The Aromaticity of the Stannole Dianion

Abstract

Delocalization in heterocycles: Reaction of hexaphenylstannole with excess lithium gives the dilithium stannole as deep-red crystals. The aromaticity of the dianion was examined by NMR spectroscopy, X-ray analysis (see picture), and calculations. The dianion has considerable aromatic character and is reported to be the first tin-containing carbocyclic aromatic compound.