Two-Heptagon Saddle-Shaped Nanographene as a Host for Fullerene Assembly

A two-heptagon saddle-shaped nanographene was synthesized through a palladium-catalyzed [4+3] decarboxylative annulation as a key step. This negatively curved π-system binds C₆₀ and C₇₀ with moderate affinities with distinct supramolecular architectures. C₆₀ of the (C₆₀)₂⊂1 complex assembles into perpendicular zigzag arrays with short interfullerene contacts, whereas C₇₀ of the C₇₀⊂1 complex adopts a unidirectional zigzag arrangement. These findings demonstrate that negative curvature and substituent placement influence supramolecular packing, offering design principles for fullerene-nanographene assemblies.