A "turn-on" fluorescent sensor for the selective detection of mercuric ion in aqueous media

A water-soluble turn-on fluorescent sensor for Hg(II) is described. Incorporation of soft thioether donors into an aniline-derived ligand framework that can be linked to a fluorescein platform affords sensor MS1, which shows a approximately 5-fold increase in integrated emission upon addition of 1 equiv of Hg(II). The synthesis and metal-binding properties of MS1 are discussed, and its ability to detect environmentally relevant concentrations of Hg(II) is demonstrated.