'Sulflower' circulene debuts

Sometimes a molecule's name is inspiration enough to instigate its synthesis. But the molecule nicknamed "sulflower"—a mash-up of sulfur and flower—recently synthesized by a team in Russia, has more going for it than a clever moniker (Angew. Chem. Int. Ed., DOI: 10.1002/anie.200602190). The compound (shown), also known as octathio[8]circulene, (C₂S)₈, represents a new form of carbon sulfide, according to Valentine G. Nenajdenko and colleagues at Moscow State University. Sulflower is the first fully heterocyclic circulene, and it may possess electronic properties similar to those of other oligothiophenes, which are popular materials in light-emitting devices and thin-film transistors. The researchers started from an eight-membered carbon ring symmetrically fused with four thiophene moieties. They then sulfurized the unsubstituted carbon atoms of the thiophene moieties, and acidification and vacuum pyrolysis knit the acyclic sulfur atoms of this intermediate into the circulene. By varying the heteroatoms, Nenajdenko hopes to make other novel heterocyclic circulenes.