A C216-Nanographene Molecule with Defined Cavity as Extended Coronoid.

We describe the first coronoid nanographene C216-molecule. As an extended polycyclic aromatic hydrocarbon containing a defined cavity, our molecule can be seen as a model system to study the influence of holes on the physical and chemical properties of graphene. Along the pathway of an eight-step synthesis including Yamamoto-type cyclization followed by 6-fold Diels-Alder cycloaddition, C216 was obtained by oxidative cyclodehydrogenation in the final step. The defined molecular structure with a cavity was unambiguously validated by MALDI-TOF mass spectrometry and FTIR, Raman, and UV-vis absorption spectroscopy coupled with DFT simulations.