Direct coordination of metal ions to cucurbit[<Emphasis Type="Italic">n</Emphasis>]urils

Cucurbitn]urils (Qn]) are promising ligands for the coordination of metal ions, metal complexes or clusters, and form various Qn]-based complexes. Among the Qn] complexes, those formed by direct coordination between Qn]s and metal ions are partic- ularly important. The direct coordination of metal ions to cucurbitn]urils leads to the formation of Qn]-based molecular capsules, tubular polymers and molecular bracelets, which could have nanoscale applications in drug delivery, molecular devices and new materials.