A Decatwistacene with an Overall 170° Torsion

Two different lengths of twistacenes, namely hexatwistacene and decatwistacene, induced by steric hindrance between imide groups and neighboring annulated benzene rings, were synthesized by bottom-up synthesis of palladium-catalyzed Suzuki cross-coupling and C-H activation. Single-crystal X-ray analyses revealed that decatwistacene, which is the longest twistacene reported, exhibits an astonishing overall end-to-end torsion angle of about 170°, the largest torsion angle reported. Both twistacenes have an enhanced solubility and stability with respect to light and oxygen owing to their large twisting deformations together with much lower LUMO levels caused by the introduction of imide groups, opening a window to the narrowest chiral graphene nanoribbons with good stability and processability.