Fluorescent Chemosensors For Mercuric Ion And Their Application In Bioimaging

Fluorescent chemosensors have the ability to selectively recognize objective molecules, and they make optical information as their output signal. In this thesis, we develop new fluorescent and phosphorescent chemosensors to recognize Hg²⁺, including : (1) Some iridium(Ⅲ) complexes containing sulfur element were designed and synthesized as phosphorescent chemosensors for Hg²⁺. (2) A rhodamine derivative FD10 was designed as fluorescent chemosensor to recognize Hg²⁺, and to further monitor intracellular Hg²⁺. In additional, we also synthesized oil-soluble and water-soluble Y₂O₃ nanocrystal.1. Fluorescent (phosphorescent) chemosensors for Hg²⁺ and the application in bioimaging(1) Iridium(Ⅲ) complexes as Hg²⁺-selective chemosensors and the application in bioimagingOn basis of the strong interaction between Hg²⁺ and sulfur, 2-(pyridin-2-yl)benzo[d]thiazole and 2-phenylbenzo[d]thiazole containg sulfur element were introduced as the ligands and four iridium(Ⅲ) complexes were synthesized as phosphorescent chemosensors for Hg²⁺. In particular, iridium(Ⅲ) complex 1 was investigated by UV-Vis absorption and fluorescence emission spectra. Furthermore, confocal laser scanning microscopy experiments showed that the compound 1 could stain cytoplasm of living cells.(2) Fluorescence turn-on chemosensor for Hg²⁺ based on a rhodamine derivative and the application in bioimagingBecause of large molar extinction coefficient, visible wavelength excitation and high fluorescence quantum yield, rhodamine B-based dyes are excellent candidates for the fluorescent probe. Herein, a rhodamine derivative of FD10 was synthesized to recognize Hg³⁺. When Hg²⁺ existed in the system, the fluorescence of the solution increased at the band of 585nm, and the colorless solution turned to light red. By means of confocal laser scanning microscopy experiments, FD10 could penetrate the membrane of HeLa cells and monitor mercuric ions in living cells.2. Synthesis of Y₂O₃ nanoparticals using thermolysis and polyol methodYttrium oxide (Y₂O₃) has a broad transparency range, a high refractive index, better thermal conductivity, and low photon energy. Therefore, it is an attractive choice as the host material applied to fluorescent research. In this part, we synthesized the oil-soluble and water-soluble Y₂O₃ by thermolysis method and polyol method, respectively. Powder X-ray diffraction (XRD) patterns and transmission electron microscopy (TEM) analysis indicated that these samples had weak crystallinity and large diameter.