Design, Synthesis And Properties Of Xanthene Fluorescent Probe Molecules

Fluorescence probe has excellent properties such as good selectivity, high sensitivity, easy to operate, and non-destructive et al. It has been widely used in the recognition and sensing of biologically and environmentally important species such as metal ions, anion, small biological activity molecules. Xanthene fluorescence probe has received more attentions due to the high fluorescence quantum yield, high stability against light, large molar extinction coefficient, long absorption and emission wavelength. The main work of this thesis was the design and synthesis of several fluorescent sensors based on xanthenes, and studied on recognition properties of them for cations and small activity molecules that contains S atom. The potential application value of these fluorescent probes in the environment or biological systems has also been discussed.In the first part of the thesis, the back ground of this thesis, the definition, structure and several recognition principles of fluorescence probes were briefly introduced. The recent progress on fluorescence probes for metal ions (Cu2+, Fe3+, Hg2+), biological thiols, S-nitrosothiols and benzenethiols have also been well summarized.In the second part, three fluorescent probes based on rhodamine B and sugars were designed and synthesized. The three probes exhibited high selectivity and excellent sensitivity detection for Cu2+ in CH3CN-H2O solution, the significant color changes in the solution could be used for naked-eye detection of Cu2+. Their detection limit for Cu2+ can meet the Chinese national drinking water standards. Furthermore, fluorescence imaging experiments of Cu2+ ions in living cells demonstrated their value of practical applications in biological systems.In the third part, three fluorescent probes based on rhodamine B were designed and synthesized. The three probes exhibited high selectivity and excellent sensitivity detection for Fe3+ in CH3OH-H2O solution, the significant color changes in the solution could be used for naked-eye detection of Fe3+. Furthermore, fluorescence imaging experiments of Fe3+ ions in living cells demonstrated their value of practical applications in biological systems.In the fourth part, three types of fluorescent probes (HgP1, HgP2) based on rhodamine B were designed and synthesized. Probe HgPl exhibited high selectivity and sensitivity for Hg2+ over other commonly coexistent metal ions and anions in water, the significant color changes in the solution could be used for naked-eye detection of Hg2+. HgP1 overcame the drawbacks of which the conventional Hg2+ fluorescent probes needed the participation of an organic co-solvent in recognition system. Probe HgP2 exhibited high selectivity and sensitivity for Hg2+ over other commonly coexistent metal ions and anions in C2H5OH-H2O solution. Furthermore, fluorescence imaging experiments of Hg2+ ions in living cells demonstrated that both of the two probes have potential value of practical applications in biological systems.In the fifth part, three sulfonyl benzothiazole-based fluorescent probes for the detection of biothiols (cysteine, homocysteine, and glutathione) were developed based on thiol-mediated nucleophilic aromatic substitutions. The probes exhibited good selectivity and sensitivity toward biothiols over other analytes in PBS buffer (50 mM, pH 7.4) with 10% DMSO. Probe RSHP3 was successfully applied for visualizing endogenous thiols in living cells, this result demonstrated its value of practical applications in biological systems.In the sixth part, a new fluorescent probe based on fluorescein for the detection of SNO compounds was designed and synthesized. The probe exhibited good selectivity and sensitivity toward SNO substrates, including the endogenous GSNO in Tris-HCl buffer (50 mM, pH 7.4,1% DMSO). The probe was successfully applied for detection of GSNO in diluted deproteinized bovine plasma, the result indicated that it was suitable for sensitive analysis of GSNO in biological samples.In the seventh part, a new fluorescent probe using a nucleophilic addition reaction strategy for the detection of PhSH was designed and synthesized. The probe proved to be sensitive, highly selective for benzenethiols in PBS buffer (50 mM) with 5% DMSO.