Studies On Fluorescent Chemosensors For Zn²⁺ And Hg²⁺

Fluorescent chemosensors not only could detect guest molecules especially rapidly and on-line, but also have the advantages such as high selectivity, high sensitivity and expedience. Among toxic chemical monitoring and environmental science, chemosensors with high selectivity and sensitivity to sense transition metal ions become a research upsurge. We have designed and synthesized a series of Schiff base ligand, and studied the properties of selective recognition for metal ions. Functionalized nanoparticles as chemosensor also have been studied. This dissertation is divided into four chapters.In chapter 1, the design principle and mechanism, research on fluorescent sensor for Hg2+ and Zn2+ have been reviewed. The application of functionalized nanoparticles by fluorescent sensors has also been expounded.In chapter 2, the design and synthesis of a series of fluorescent sensors for Zn2+ based on Schiff base have been presented. The relationship between the structures of these ligands and their complexes and the selectivity was studied. The results suggested that substituent and solvent were very importent for the complex structures and fluorescent selectivity.In chapter 3, two fluorescent chemosensors using rhodamine as a fluorephore have been synthesized, and they were able to selectively recognize Hg2+In chapter 4, fluorescent chemosensors could selectively recognize metal ions, which can be introduced to the surface of nanoparticles. We have designed and synthesized inorganic-organic hybrid materials Rhol-Fe3O4@SiO2, Rho2-Fe3O4@SiO2, Rho3-Fe3O4@SiO2, Rhol-SiO2, Rho2-SiO2 and Rho3-SiO2. Rhol-Fe3O4@SiO2 exhibited selective'turn-on'type fluorescent enhancements and distinct color changes with Hg2+. And Rho3-SiO2 could also act as chemosensor for Hg2+. The final products not only possess the properties of the nanopaticles, but also have selectivity for metal ions.