N-Bordered Rylene Arches via Programmable Curved π-Extension

Curved molecular carbons have captured significant concerns due to their distinct properties from planar analogues and topologies serving as segments of diverse nonplanar carbon allotropes. Notably, aromatic ribbons featuring continuously and directionally curved π-surface have been theoretically predicted to be critical to circular carbon analogues, but have remained a synthetic challenge in chemistry. Herein, we address the synthesis and properties of arch-shaped N-bordered nanoribbons which feature rylene backbone attached by five-membered rings at the armchair-edges via a programmable curved π-extension strategy. X-ray crystallographic analyses reveal their directionally and continuously curved π-surfaces with arched topologies and high arch-to-arch inversion barrier according to VT 1H NMR and theoretical calculations. Notably, the resultant quaterrylene arch exhibits a boosted Φf in solution compared to planar quaterrylene diimides and can be associated with C60 in solution and solid state. This work opens a pathway for investigating new series of curved graphene nanoribbons and provides an opportunity for the promising synthesis of relevant long-cherished carbon nanobelts.