Synthesis And Recognition Properties Of Fluorescent Probes Based On Rhodamine And Fluorescein Deravitives

As important fluorescent materials, rhodamine and fluorescein dyes are common choicesfor designing fluorescent probes because of their special structure and excellent fluorescentproperties. In this paper, five fluorescent probes based on rhodamine and fluorescein weredesigned and synthesized to detect copper ion and hypochlorite anion. The molecularrecognition abilities and mechanisms were identified by UV-visible and fluorescence spectra.The details are summarized as follows:（a） In chapter 2 and 3, a series of fluorescent probes （RGPH、R6GH、FLPH and FLH）base on the dyes of rhodamine 6G and fluorescein were designed and synthesized. Thecompounds were identified by¹H NMR,¹³C NMR, elemental analysis and MS. Therecognition properties of molecular probes were investigated. These fluorescence molecularprobes exhibited a high sensitivity for ClO^-in netural aqueous solution and with detectionlimit of 5.0×10^-9M, 2.0×10^-8M, 2.0×10^-8M and 2.0×10^-8M, respectively. After addingClO^-, the chemosensor induces UV-visible and fluorescencnt enhancement. In addition,RGPH and R6GH are pH-insensitive ClO^-fluorescent probes, which would detect ClO^-effictively in a relatively wide range of pH.（b） In chapter 4, a highly sensitve fluorescent probe （RBPH） base on rhodamine B forselective detection of Cu²⁺was developed. The structure of this probe was determined by1HNMR,13C NMR, elemental analysis and MS. UV-visible and fluorescence spectra are selectedas the detection signal to research the recognition properties for various metal ions. Theresults show that RBPH had no fluorescence and UV absorption in acetonitrile-water-BoricAcid-Na₂B₄O₇buffer pH = 7.4 （1: 1: 1, v / v / v）. It showed a better selectivity and higher sensitivityfor Cu²⁺over the other metal ions. The solution changed rapidly from colorless to rose andshowed strong fluorescence intensity and UV absorption upon the addition of Cu²⁺with adetection limit of 3.5×10^-10M.