Cyclic conjugation in benzo-annelated coronenes

Abstract

The cyclic conjugation in benzo-annelated coronenes is studied by means of the energy effect (ef) and π-electron content (EC) of the six-membered rings. Some peculiarities of the π-electron structure of benzo-coronenes, inferred by the Clar aromatic sextet theory, could be tested and verified. A regularity that earlier was discovered in the case of perylene congeners is now shown to hold also for benzo-annelated coronenes: Benzenoid rings that are annelated linearly with regard to the central hexagon H0 of coronene decrease the intensity of cyclic conjugation in H0 and this effect is proportional to the number of linearly annelated rings. A very good linear correlation exists between the ef- and EC-values.