A highly sensitive and selective fluorescent probe for Hg2 + and its imaging application in living cells

Two rhodamine-based Hg2 + probes L1 and L2 were prepared and confirmed by NMR, MS and crystal data. The sensing behavior of these probes was studied by UV–visible and fluorescence spectroscopy. The probe L1 couldnʹt be widely applied in aqueous media or mixed media because of its poor solubility. However, the probe L2 displayed selective and sensitive fluorescence enhancement response to Hg2 + at physiological pH value for biological use. The selectivity of this system for Hg2 + over other metal ions was remarkably high, and its sensitivity was at ppb level. The probe L2 responded rapidly to Hg2 + in aqueous solutions with a 1:1 stoichiometry and was successfully applied to image Hg2 + in living cells.