Synthesis And Application Of Rhodamine-type Heavy Metal Ion Fluorescence Probe

Today,the problem of heavy metal pollution in the environment is increasing,and some heavy metals play a very important part in our people and animals.In many heavy metal ion detection methods,the fluorescent molecular probes have the advantages of easy operation,selectivity and high sensitivity.At the same time,Rhodamine-type fluorescent dyes have the advantages of low toxicity,good water solubility and high light quantum yield.So the researchers are widely concerned about the Rhodamine-type fluorescent molecular probe.In this paper,we summarize the research progress of Rhodamine-type fluorescent molecular probe.On this basis,three kinds of fluorescence probes were designed and synthesized by using rhodamine derivatives as the matrix.The details are as follows:First,a novel fluorescent probe based on dansyl-appended rhodamine B was developed.The receptor can selectively recognize and sense Hg²⁺ and Cu²⁺ from other common metal ions by showing unique fluorescence and absorption characteristics.In MeCN/HEPES buffer solution,the probe gives a ratiometric fluorescent response to Hg²⁺,which was ascribed to the fluorescence resonance energy transfer from dansyl moiety to the ring-opened rhodamine B moiety,but the presence of Cu²⁺ causes fluorescence quenching.Beside the fluorescence change.Second,a new rhodamine-based fluorescent probe has been designed and synthesized by linking rhodamine 6G hydrazide with N-methylisatin via an imine linkage.The receptor can selectively recognize and sense Pb²⁺,Hg²⁺ and Cd²⁺ by showing different fluorescence characteristics.In ethanol/HEPES buffer medium,the addition of Cd²⁺ caused a yellowish-green fluorescence,while the presence of Pb²⁺ or Hg²⁺ gave rise to an orange fluorescence.Additionally,the sensor shows an irreversible fluorescence response to Pb²⁺ and reversible fluorescence responses to Hg²⁺ and Cd²⁺.Third,Herein rhodamine B and 7-?diethylamino?-3-formylcoumarin were conjugated by ethanediamine to afford a pH-sensitive fluorescent compound,and its structure was confirmed by NMR,MS and X-ray single crystal diffraction.