Structures and Supramolecular Properties of Inclusion Complexes of Anthracene‐Triptycene Nanocages with Fullerene Guests and Their Dynamic Motion as Molecular Gyroscopes
Takuji Mitani, Eiji Tsurumaki, Shinji Toyota
Abstract
Abstract Three derivatives of macrocyclic cage compounds consisting of diarylanthracene and triptycene units were synthesized. These nanocages formed host‐guest complexes with C 60 and other fullerene guests as confirmed by 1 H NMR and fluorescence spectroscopy. The association constant of the mesityl and 2,4,6‐tributoxyphenyl derivatives with C 60 was determined to be 2.2 × 10 4 L mol −1 , which was larger than that of the pentafluorophenyl derivative. Direct experimental evidence of the complexation was obtained by X‐ray diffraction analysis: the guest C 60 molecule was included in the cavity via multipoint CH⋅⋅⋅π interactions. Dynamic disorders of the included C 60 molecule in variable‐temperature X‐ray analysis indicated uniaxial motion, such as gyroscopic motion. The unique dynamic behavior of the spherical C 60 rotor anchored by the cage stator via CH⋅⋅⋅π interactions in the crystal, as well as substituent effects on the association properties, are discussed with the aid of DFT calculations.