Highly selective absorption of polychloromethanes in perhydroxylated cucurbit[6]uril-based supramolecular assemblies

Abstract

Two perhydroxylated cucurbit[6]uril-based supramolecular assemblies have been obtained via crystallization of perhydroxylated cucurbit[6]uril {(HO)₁₂Q[6]} from aqueous HCl solutions of different concentrations. Single-crystal X-ray diffraction (unit cell) analysis revealed that (HO)₁₂Q[6] molecules interacted with water molecules through hydrogen bonding, thereby forming solid supramolecular assemblies with different kinds of channels. These selected channels were formed from the stacking of (HO)₁₂Q[6] molecules in a portal-to-portal manner and between the outer surfaces of (HO)₁₂Q[6] molecules. Unlike normal or alkyl-substituted Q[n]-based supramolecular assemblies, which generally exhibit highly selective absorption of methanol, the (HO)₁₂Q[6]-based supramolecular assemblies exhibit highly selective absorption of polychloromethanes.