Contorted two-dimensional aromatic molecules are fascinating synthetic targets because they are molecular "cutouts" of nonplanar graphene structures, fullerenes, or carbon nanotubes. In most cases, the curvature is introduced by the implementation of either five-, seven-, or eight-membered rings into the fused aromatic plane. Curvature can also be generated for two-dimensional systems consisting of six-membered rings exclusively, by the introduction of cove or fjord regions. The synthesis of a polycyclic aromatic hydrocarbon (PAH) that contains two peripheral triptycene units and six tert-butyl substituents is described. As a result of steric repulsion, the structure is highly contorted with two phenylene blades of the peripheral triptycene units oriented almost coplanar with respect to each other at a distance of 16 Å, as has been verified by single crystal X-ray diffraction. The conformation is stable in solution even at a temperature of 150 °C. Additionally, internal tert-butyl groups could be selectively removed, allowing a UV/Vis-spectroscopic comparison of two structures with the same π-system, but different degrees of contortion.

Lock ’em up!Two tert‐butyl groups affect the conformational flexibility and emissive properties of a hexabenzoovalene. In their Communication on page 15594 ff, M. Mastalerz et al. describe “locking up” of a flexible precursor to an orange‐emitting hexabenzoovalene by oxidative cyclodehydrogenation, and release of the conformationally “locked” compound by selective dealkylation to give a flexible green‐emitting hexabenzoovalene.

Unter Arrest Zwei tert‐Butyl‐Gruppen beeinflussen die konformative Flexibilität und die Lichtemission eines Hexabenzoovalens. In ihrer Zuschrift auf S. 15823 ff. beschreiben M. Mastalerz et al., wie sich eine flexible Vorläuferverbindung durch oxidative Cyclodehydrierung zu einem orange emittierenden Hexabenzoovalen konformativ einfangen lässt. Eine selektive Dealkylierung gibt dem System seine Bewegungsfreiheit zurück – es emittiert grün.