Alkali and alkaline earth metal ion binding by a foldamer capsule: selective recognition of magnesium hydrate.

Alkali and alkaline earth metal ion binding by an aromatic oligoamide foldamer was shown to induce its folding into a helical capsule. CD and NMR titrations revealed tight and selective binding of Mg2+ . Crystallographic studies demonstrated that, depending on the metal, binding may involve the first or second coordination spheres of the metal hydrates.