Selective removal of Cr 2 O 7 2- in aqueous solution by nonporous pure crystals of cucurbit[6]uril.

Cucurbit[6]uril (Q[6]) could serve as a selective absorbent for the toxic anion Cr 2 O 7 2- , which was demonstrated by the results of UV-vis, ICP, XPS, SEM, and EDS experiments. Single-crystal X-ray diffraction analysis revealed that capture capacity could be attributed to the outer-surface interactions of cucurbit[ n ]uril between Cr 2 O 7 2- and the outer surface of Q[6].