Supertrityl Radical and Cation: The Effect of a Large π-Surface for Intermolecular Interactions and Spin/Charge Delocalization.

We report the synthesis and properties of supertrityl radical and cation bearing three hexa-peri-hexabenzocoronenes (HBCs). X-ray analysis of the cation revealed a propeller-shaped structure forming a two-dimensional honeycomb assembly via π-π stacking. The radical exists in monomer-dimer equilibrium with a multicenter pancake bond. Despite large π-surfaces, spin/charge remain localized at the central carbon, rationalized by Clar's sextet rule.