Anion recognition and templation in coordination chemistry

The selective recognition of anionic species by molecular receptors is an area of increasing interest due to the important roles played by anions in biological systems and the environment. An attractive approach for the recognition of anions is to use metal-based receptors, which provides some important advantages over purely organic hosts. Metallo-hosts can combine the structural and functional properties of metal centres with the recognition capabilities of organic ligands to selectively bind anionic guests. In our group we have developed different approaches for the synthesis of this type of metallo-receptors. One of these approaches is based on the use of the anion of interest as a templating agent to link together different organic and metal-containing building blocks into assemblies that have high selectivity for the templating anion. This microreview aims to give an overview of the research carried out in the author's group in this area over the past few years. Relevant examples from other groups are discussed and, where appropriate, compared to the work carried out in our group. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).