Host–guest complexes of cucurbit[6]uril with isoprenaline: the effect of the metal ion on the crystallization pathway and supramolecular architecture

Abstract

We report on the three host–guest complexes between the cucurbit[6]uril macrocycle and the catecholamine drug isoprenaline obtained in the presence of magnesium or calcium ions. The metal ions affect both the crystallization pathway of the CB6–isoprenaline complexes and the supramolecular architecture in the solid state. In the case of the magnesium cations the sequential crystallization of the metal-free and the magnesium containing forms of the host–guest complexes was observed, while the use of calcium cations resulted in the direct crystallization of the calcium-coordinated CB6–isoprenaline complex.