Highly Selective Construction of D₂-Symmetric Chiral Carbon Nanorings and the Diverse Assembly With Fullerenes

Chiral carbon nanorings have attracted significant attention due to their unique structures and properties. However, their synthesis faces challenges such as low selectivity and tedious separation processes, while their hierarchical supramolecular self-assembly behaviors remain largely unexplored. In this study, we designed a chiral fused-ring building block with a nearly right-angle bend, enabling the efficient construction of chiral carbon nanorings with D₂ symmetry, namely D₂-(P)-NR3 and D₂-(M)-NR3. The resulting nanorings exhibited diverse multi-level cooperative assembly with fullerene molecules. At the host-guest level, C₆₀ was encapsulated within the nanoring cavity in an "in-ring" binding mode. In contrast, the larger C₇₀ was accommodated above the cavity in an "on-ring" fashion, forming a host-guest complex reminiscent of a "straw hat." At a higher level of assembly, the C₆₀-based complexes further self-organized into a 4-fold superhelix, while the "straw hat"-shaped complexes of C₇₀ stacked via concave-convex complementarity to form one-dimensional tubular structures. On the mesoscopic scale, the C₆₀ complexes assembled into helical nanofibers, whereas the C₇₀ complexes formed microplates.