The electrochemical and spectral recognition of chloride anions by novel acyclic ruthenium(II) bipyridyl receptor complexes is demonstrated. The low energy metal-to-ligand charge-transfer (MLCT) emission band of the complexes and inherent sensitivity of the technique suggests that fluorescence emission spectroscopy offers particular promise in analytical applications. The principle of anion recognition based on the suitable design of the receptor complexes will be applicable to a range of analytes.
