Phenacenes: A family of graphite ribbons. 1. Syntheses of some [7]phenacenes by stilbene-like photocyclizations

Abstract

The largest previously reported phenacene, the name we propose for the family of polycyclic aromatic compounds having fused benzene rings in an extended phenanthrene-like structural motif, contains only six rings ([6]phenacene). We have employed stilbene-like photocyclizations to synthesize the unsubstituted [7]phenacene, an extremely insoluble compound, as well as 2,13-di-n-pentyl[7]phenacene and 2,13-di-tert-butyl[7]phenacene, two alkyl-substituted derivatives with greatly improved solubilities.