Inclusion Complexes and Solvates of Buckycatcher, a Versatile Molecular Host with Two Corannulene Pincers

X-ray crystal structure study of cocrystallites of buckycatcher (2, C60H28) demonstrates a remarkable versatility of the molecular clip to accommodate guest molecules of various sizes and shapes. As demonstrated by the B97-D calculations, concave–concave conformation of the clip seems to be preferred for the gas-phase 1:1 inclusion complexes of 2 with a series of potential guests. However, the unprecedented concave–convex conformations were found in two of the reported solvates [i.e., 2·0.75­(p-xylene) and 2·2PhNO2]. Three of the studied inclusion complexes with the highest calculated gas-phase binding energies (1,3,5-trinitrobenzene@2, and the previously reported C60@2 and C70@2) exhibit the analogous 1:1 supramolecular arrangements in the crystal state. On the other hand, p-xylene and PhNO2 solvates as well as DDQ/MeCN cocrystallite exhibit quite different stoichiometries and supramolecular arrangements, presumably enforced by the crystal packing forces. Dramatic variations of the intercentroid distances between the central five-membered rings of the corannulene pincers in the inclusion complexes (from 7.87 to 11.51 Å) expose an impressive flexibility of the buckycatcher tether.