Cyclic conjugation in benzo-annelated triphenylenes

Abstract

Cyclic conjugation in benzo-annelated triphenylenes was studied by means of the energy effect (ef) and the p-electron content (EC) of the six- -membered rings. A regularity that was earlier discovered in the case of acenaphthylene and fluoranthene congeners is now shown to hold also for benzo-annelated triphenylenes: Benzenoid rings that are annelated angularly with regard to the central six-membered ring Z0 of triphenylene increase the intensity of the cyclic conjugation in Z0, whereas linearly annelated benzenoid rings decrease the cyclic conjugation in Z0. The ef- and EC-values are strongly correlated, yet in a non-linear manner.