Selective and sensitive fluorescence-shift probes based on two dansyl groups for mercury(ii) ion detection

Abstract

Two probes ( 1 and 2 ) bearing two dansyl fluorophores were synthesized and applied to the detection of mercury(II) ions in aqueous solution. These probes exhibited a selective response to Hg²⁺ in a buffered solution, with high sensitivity and a unique fluorescence response signal which displayed a blue-shift effect in the fluorescence emission peak. The Hg²⁺ recognition mechanisms of the probes were determined by NMR spectroscopy, ESI-MS and UV-vis spectroscopy. The results showed that probe 1 and mercury(II) ions formed an unusual 2 : 2 stoichiometric ratio complex, while probe 2 and Hg²⁺ formed a multidentate complex with a stoichiometric ratio of 2 : 1.