Cylindrical and Conical Conjugated Nanobelts by Longitudinal Extension of Cycloparaphenylene and Their Double-Walled Assembly

Constructing carbon nanotubes and related segments with atomic precision remains challenging, despite significant advances, including cycloparaphenylene (CPP), carbon nanobelts, and phenine nanotubes. Here, we report three conjugated nanobelts ( NB1 – NB3 ) constructed by longitudinal π-extension of CPP with rings of the same, smaller, or larger size. Each nanobelt comprises three fused aromatic units bridging two axial CPP rings, which mediate the intermolecular assembly. NB1 – NB3 have a delocalized electronic structure, showing largely red-shifted emission. The smaller NB2 can insert into NB3 to form a stable double-walled assembly ( NB2 ⊃ NB3 ), which exhibits energy transfer with nearly 100% efficiency.