Fluorescein-based fluorescent and colorimetric chemosensors for copper in aqueous media

Two new fluorescein-based chemosensors for Cu2+ were designed with highly selective “off-on” behavior, one of them working in both absorption and emission, the other only in absorption. Binding to Cu2+ binding is reversible, as indicated by the bleaching of the color when the metal is extracted. The compounds form the basis for rapid, selective and sensitive Cu2+ chemosensors in aqueous media.