Crystal Structure of Hexaazaoctadecahydrocoronene Dication [HAOC] 2+ , a Singlet Benzene Dication

The structures of hexaazaoctadecahydrocoronene, [HAOC](n) (n = O, + 2), have been determined by single-crystal x-ray diffraction. Although HAOC is aromatic, its dication has a localized structure that is based upon Jahn-Teller-distorted cyanine/p-phenylenediammonium fragments. The structure is consistent with the singlet ground state as determined by magnetic susceptibility and contrasts with the simplest Hückel expectation of a triplet ground state.