A thioether-rich crown-based highly selective fluorescent sensor for Hg(2+) and Ag(+) in aqueous solution.

A new fluorescent sensor 1, based on the naphthalimide chromophore and thioether-rich crown receptor, exhibited dual signaling behaviors for Hg(2+) and Ag(+) in aqueous solution. Upon addition of Hg(2+), the fluorescence intensity enhanced in a linear fashion with a quantum yield increase of about 5-fold. Moreover, with the 1-Hg(2+) complex, Ag(+) was easily recognized by a marked fluorescence quenching. The living cells image experiments demonstrate the value of sensor 1 in fluorescent visualization of Hg(2+) ions in biological systems.