Novel fluorescent sensor for Ag+ and Hg2+ based on the BINOL-pyrene derivative via click reaction

A novel BINOL-pyrene derivative sensor 1 for Ag+ and Hg2+ incorporating the triazole moieties and pyrenes was synthesized via click reaction. Binding of Ag+ ion induces the formation of 1:1 Ag+–1 chelating complex, and occurs in a ratiometric manner through an enhanced monomer and declining excimer emission, which make it possible to ratiometrically detect Ag+. The competitive experiment shows 1 can be used as an Ag+ specific fluorescence sensor over a wide range of competing cations. In the meanwhile, the sensor 1 was found to be selectively quenched by only Hg2+ at both monomer and excimer emission. Furthermore, we obtained evidences for different fluorescence signaling behaviors with Ag+ and Hg2+ by 1H NMR titration experiments.