Specific and Oriented Encapsulation of Fullerene C₇₀ into a Supramolecular Double‐Decker Cage Composed of Shape‐Persistent Macrocycles

An efficient strategy for the specific recognition of ellipsoidal fullerenes uses molecular containers with well‐designed three‐dimensional (3D) nanospaces. We describe the synthesis of a supramolecular double‐decker cage composed of shape‐persistent metallomacrocycles and pillar ligands. A discrete 3D nanospace was built within the molecular framework of the shape‐persistent‐macrocycle/bidentate‐pillar molecule. The single‐crystal structure of the supramolecular cage reveals a uniquely shaped inner cavity with a size and net volume (>670 Å 3 ) that are well matched to the shape and size of C 70 . The cage exhibited higher selectivity for C 70 over C 60 , the smaller carbon allotrope. We suggest that such C 70 ‐selective recognition is derived from multiple CH–π interactions between hydrogen atoms inside the cage and C 70 .