The Synthesis, Characterization And Applications Of Fluorescent Indicators Of Fiber-optical Oxygen Sensor

Oxygen is involved in lots of important chemical and biochemical reactions. It is more and more important to investigate oxygen in a great deal of research fields such as chemical industry, medicine, biology, environmental protection and so on. At the same time, the technology of fiber-optical oxygen sensor is developed greatly. Up to date, all the designs of the technology of fiber-optical oxygen sensor are based on the mechanism of fluorescence quenching. Therefore, synthesizing fluorescent indicators which have high sensitivity and selectivity for determination of oxygen are desirable. Four Chapters is included in this thesis. In Chapter 1, the review of fluorescent indicators for oxygen, and the method of synthesis of 1,10-phenanthroline and its derivatives, as well as the development of metal complexes of 1,10-phenanthroline and its derivatives were described. In addition, the scheme of this thesis were proposed. In Chapter 2, using 1,10-phenanthroline as the raw material, four ligands such as dipyrido[3,2-a:2`,3`-c]phenazine(Dppz),tetrapyrido[3,2-a:2`,3`-c:3``,2``-h:2```,3```-j]phenazine(Tpphz), 10,11-[1,4-naphtalendione] dipyrido [3,2,-a::2`,3`-c] phenazine (Aqphen) and 2-[4-hydroxylphenyl]imidazo [4,5-f] [1,10] phenanthroline (Hpip) were synthesized. Moreover, seven ruthenium(II) phenanthroline derivatives were also synthesized. The synthesis of Ru(Hpip)3Cl2 and Ru(phen)2AqphenCl2 have not yet been reported, and a new and effective method for the synthesis of Ru(Dppz)3(DS)2 was also investigated. All the complexes synthesized in our experiments were characterized by elemental analysis, IR and UV-Vis absorption spectra, respectively. The values of N, H, C are respectively coincident to the theoretic values. The object organic groups in the complexes were also confirmed by IR spectra. And the typical metal-to-ligand charge transfer(MLCT) (absorption Wavelength near 450nm in ethanol solution )of all the ruthenium(II) complexes were displayed in UV-Vis absorption spectra. In Chapter 3, all the complexes synthesized in our experiments were investigated by fluorescence spectra and cyclic voltammetry(CV) respectively. Excitation wavelength and the emission wavelength of all the complexes were obtained. Ru(phen)2Tpphz(DS)2 has a larger Stocks shift than the others and the value is about 220nm. Additionally, the electrochemical behaviors of these complexes in the organic solvent were investigated. The oxidation of metal ion of these complexes is closely relative to the ligands and Ru(Hpip)3Cl2 behaves the most sensitive electrochemical activity.In Chapter 4, the water-solubility of these complexes was investigated. The result shows that all the complexes hardly dissolve in the water except Ru(phen)2AqphenCl2. The complexes which are not soluble in water will be helpful to be the indicators of fiber-optical oxygen sensor to determine the dissolved oxygen in the seawater. A simple system to determine the values of fluorescent quenching of the complexes in the presence of oxygen was design. As a result, the Ru(Dip)3(DS)2 was promising as the best indicator of fiber-optical oxygen sensor due to its high sensitivity to oxygen.