A thioether-rich crown-based highly selective fluorescent sensor for Hg2+ 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 Hg2+ and Ag+ in aqueous solution. Upon addition of Hg2+, the fluorescence intensity enhanced in a linear fashion with a quantum yield increase of about 5-fold. Moreover, with the 1-Hg2+ 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 Hg2+ ions in biological systems.