Corannulene-Driven Curvature Engineering Enhances Fullerene Encapsulation in a Carbon Nanohoop

Integrating intrinsically positively curved polycyclic aromatic hydrocarbons (PAHs) into cycloparaphenylene (CPP) frameworks remains challenging. In this study, we report a concise synthesis of a functionalized dibenzocorannulene unit via sulfone addition, followed by its seamless fusion into a CPP backbone to afford the positively curved nanohoop DBCora[10]CPP. This unique architecture creates a deep cavity with pronounced concave-convex geometric complementarity toward fullerenes, resulting in strong binding affinities of up to 10⁸ M^-1. ¹H NMR studies reveal slow host-guest exchange behaviors in solution, while single-crystal x-ray diffraction unambiguously establishes the structure of C₆₀@DBCora[10]CPP and reveals a distinctive octahedral packing motif featuring a free fullerene at the center. Femtosecond transient absorption spectroscopy demonstrates that the precise geometric match between host and guest enables ultrafast charge-separation followed by a persistent charge-separated (CS) state with a lifetime of 1.5 ns. Notably, this performance is achieved in a purely host-guest assembly without the need for mechanical bonds or bulky stoppers. These findings demonstrate how positive-curvature engineering can simultaneously modulate fullerene recognition, host-guest dynamics, and charge-separation behavior, establishing a useful design principle for functional carbon nanohoops and supramolecular optoelectronic systems.