Hemicucurbit[6]uril, a selective ligand for the complexation of anions in aqueous solution

The complex formation between hemicucurbit[6]uril and different cations and anions has been studied using a new experimental technique. Due to the low solubility of this macrocyclic ligand, none of the common methods can be used to study the reactions in aqueous solution. The solubility of the ligand increases in the presence of salts. From these measurements, the stability constants of the complexes formed can be calculated. Hemicucurbit[6]uril does not form complexes with cations in aqueous solution. However, this ligand forms a strong complex with thiocyanate and iodide. No further anions are found so far which form complexes with hemicucurbit[6]uril.