A fluorescent turn-on probe for Hg(II) based on an NTe2 chelating motif and its application in living cell imaging

A boron dipyrromethene (BODIPY) derivative (BODTe) with an NTe2 chelating motif exhibits high selectivity for Hg2+ detection. Significant fluorescence enhancement was observed with the chemosensor BODTe in the presence of Hg2+. However, the metal ions Ag+, Al3+, Ca2+, Cd2+, Co2+, Cu2+,Cr3+, Fe2+, Fe3+, Hg2+, Mg2+, Mn2+, Ni2+, Pb2+, and Zn2+ produced only minor changes in the fluorescence values of the system. The association constant (Ka) of Hg2+ binding for the chemosensor BODTe was found to be 3.84 × 103 M−1, with a detection limit of 19.2 μM. The maximum fluorescence enhancement caused by Hg2+ binding in the chemosensor BODTe was observed over the pH range of 4.0-10.0. Confocal fluorescence microscopy imaging using RAW 264.7 cells showed that BODTe can be used as an effective fluorescent probe for detecting Hg2+ in living cells.