Selective binding and easy separation of C70 by nanoscale self-assembled capsules

An easy, highly selective separation of C₇₀ and the higher fullerenes has been achieved by solid-liquid extraction with a 2-ureido-4-[1H]-pyrimidinone-based scaffold which wraps around the guest as a dimeric capsule (see picture), thereby solubilizing it in THF. Acidification disrupts the hydrogen-bonding network and allows easy recovery of the guest and recycling of the receptor without chromatography or tedious procedures.