Coordination and organometallic compounds as anion receptors and sensors

In this tutorial review the wide-ranging use of metal ions in anion receptors is discussed with an emphasis on diversity and applications in sensing and soft materials. Metal-containing receptors are categorised according to the role of the metal as a structural unit, as a Lewis-acidic binding site or as part of a redox-active or luminescent reporter group. The differing chemistry of substitutionally inert metal complexes in anion hosts and metal-anion-ligand self-assembly processes is highlighted. The use of anion binding coordination polymer systems in anion separations and in supramolecular gels is also examined.