Highly sensitive and selective turn-on fluorescent chemosensor for Pb2+ and Hg2+ based on a rhodamine-phenylurea conjugate.

A novel easily available turn-on fluorescent chemosensor RPU based on a rhodamine-phenylurea conjugate was synthesized, which showed highly selective and sensitive recognition toward Pb(2+) in CH(3)CN and Hg(2+) in aqueous media over a wide range of tested metal ions with remarkably enhanced fluorescent intensities and also clear color changes from colorless to pink.