A three-in-one crystal of mixed sized cucurbit[n]uril homologues.

Crystallization-driven self-assembly of three macrocyclic members of the cucurbit[n]uril family is reported. The largest cucurbit[10]uril serves as a host for the smallest cucurbit[5]uril forming an inclusion complex of the macrocycle-within-macrocycle type. This supramolecular ensemble undergoes cocrystallization with cucurbit[7]uril. Such unusual cocrystallization is explained by the strong tendency of all cucurbit[n]urils to associate via multiple C–H⋯O hydrogen bonds. [ABSTRACT FROM AUTHOR]