Identification of solid-state forms of cucurbit[6]uril for carbon dioxide capture

Three novel crystalline forms of cucurbit[6]uril (CB[6], 1) have been identified by fine control of the mixing process of a hydrochloride solution of CB[6] with ethanol. The form that exists in nanoplate particles shows permanent porosity upon desolvation and the highest CO2 uptake (15 wt%) at 298 K and 1 bar among any known solid-state forms of CB[6].