Extended systems of closed helicene. synthesis and characterization of [7] and [7.7]-circulene

Abstract

The polycyclic aromatic compounds with a circular arrangement of seven benzene rings, [7]circulene, was prepared, and its unusual saddle-shaped structure with C2 symmetry was supported by its X-ray analysis. Preparation and characterization of [7.7]-circulene with unique 8-shaped and saddle-shaped geometry was also reported. © 1993 IUPAC