Composition- and size-controlled cyclic self-assembly by solvent- and C60-responsive self-sorting.

Synthesis, solvent-, and guest-controlled self-assembly, and self-sorting of new hydrogen-bonded chiral cavity receptors are reported. The design of the cavity is based on the cyclic self-aggregation of monomers containing the 4H-bonding ureidopyrimidinone motif fused with the bicylo[3.3.1]nonane framework. Selective formation of kinetically inert cyclic tetramers is observed in chloroform, while in toluene an equilibrium between tetrameric and pentameric forms exists. The high affinity of the tetrameric aggregates toward C60 and C70 is observed in aromatic solvents. The host-guest interaction of unconventional π-acidic supramolecular receptors for fullerenes is turned off and on by changing the solvent, whereas the selection of size and the very composition of the cavity aggregate is controlled by either the change of solvent or the addition of fullerene guest, making our systems a new type of self-sorting device.