| Fluorescent chemosensors for metal ion detection have attracted great interest due to their high selectivity, sensitivity, easy operation and rapid response time. Over the past few decades, fluorescent chemosensors have developed greatly, more and more fluorescent chemosensors have been reported and have been widely applied in biological sciences, environmental chemistry and clinical medicine, as well as some other areas.In this thesis, two fluorescent probes, which can be used to detect metal ions in aqueous solution with high selectivity and sensitivity, have been designed and synthesized, their structure were systematically characterized by 1H-NMR, mass spectrometry and element analysis, respectively. The absorption spectra and emission spectra of them have been thoroughly studied. The NBD-amine-based compound 1 was synthesized by connecting the NBD-Cl and quinoline derivatives by piperazine. 1 can be used to detect Fe3+ and Hg2+ in aqueous solution, and the recognition is not obviously interfered by other coexisting metal ions. In a wide range of p H, the fluorescent intensity of 1 increased 10 times in the presence of Fe3+ or Hg2+. The increase of the fluorescent intensity and the concentration of the metal ions in the concentration range of 0-20 μmol/L showed good linear relationship, so it can be used to realize the quantitative analysis of Hg2+ and Fe3+ accurately.Another new fluorescent probe 2 containing a dansyl unit as a donor and rhodamine 101 as an acceptor was developed to detect Cr3+ and Hg2+ in aqueous solution. The addition of Cr3+ or Hg2+ induced a red shift of the fluorescent peak of 2 from 515 nm to 605 nm because of the resonance energy transfer(FRET), at the same time the color of the solution changed from colorless to pink obviously. The ratio of the fluorescence intensities at 605 nm and 515 nm, respectively, versus ion concentration of Cr3+ or Hg2+ displayed a linear response in the concentration range of 0–20 μmol/L. |
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