Highly selective fluorescent sensors for mercury(II) ions and their applications in living cell imaging

Three new pyrene derivatives (MS1, MS2, and MS3) containing two triazole units exhibited fluorescence quenching in the presence of Hg2+ ions. Other metal ions Ag+, Ca2+, Cd2+, Co2+, Cu2+, Fe2+, Fe3+, K+, Mg2+, Mn2+, Na+, Ni2+, Pb2+, Rb+, and Zn2+ produced only minor changes in the fluorescence of MS1, MS2, and MS3. The binding ratio of the chemosensor-Hg2+ complexes was found to be 1:1 according to Job plot experiments. The association constants (Ka) of chemosensor-Hg2+ complexes were found to be 1.68×103 M−1 (MS1), 1.57×103 M−1 (MS2), and 1.52×103 M−1 (MS3), respectively. Moreover, fluorescence microscopy experiments showed that MS1 could be used as a fluorescent probe for detecting Hg2+ in living cells.