The Synthesis Of Cyanine Dyes、CS-NIR Dyes And Phenanthroimidazole Derivatives And Research Of Their Spectral Properties

Fluorescent molecular probes are excellent biological molecular sensors whichhave many good merits, ie., high sensitivity, rapid response time and so on. In recentyears, with the steadily development of the life sciences, organic fluorescent probeshave played an important role in proteins, nucleic acid, cell detection and immuneanalysis. As the continuous improvement of the synthesis techniques and applicationsof fluorescent probes, people will make more research and knowledge of organicfluorescent compounds, and also the development prospects of organic fluorescenceprobes will be more and more broad. Cyanine dyes applied as functional dyes aregradually extending their application fields because they have some good opticalproperties, such as wide spectral spectrum, high extinction coefficient, having thewonderful advantage of organic fluorescent probes. CS-NIR dyes, an unique NIRfunctional dyes which have the character like classic rhodamines, with high stability,good fluorescent properties and their spectra reach the near-infrared (NIR) regionwhere a biological matrix exhibits the least absorption and autofluorescencebackground. Accordingly, CS-NIR dyes can be widely used as a platform forconstruction fluorescent probes. Phenanthroimidazole is another excellentfluorophore dye in molecular design of fluorescent probe with large Stokes shift, highfluorescence photostability.In Chapter Ⅰ, we have first introduced the design principles of PET, secondly, wehave introduced cyanine dyes and their applications as pH fluorescent probes, At lastwe aslo introduced progressed research of fluorescent probes based on CS-NIR dyesand phenanthroimidazole dyes.In Chapter Ⅱ, we have synthesized two nitrogen substituted derivatives ofcyanine dyes and two isomerization products based on principles of PET, and alsostudy the transformation mechanism between them. Their structures were confirmedby1H NMR,13C NMR and MS spectrometry, and with the comparison of theirspectral properties. The derivatives of cyanine dyes. Unlike the traditional rectionconditions, the four nitrogen substituted derivatives have large Stokes shift, morethan100nm, and have widely absorption and emission spectra, very low fluorescencequantum yields, these may be attributed to the intramolecular electron transfer (PET)co-function in the four derivative dyes. And the further research of cyanine derivatives on the spectroscopic properties of pH response were carried out. Theresults showed that three derivative dyes can be used as pH probes, with turn onfluorescence and large red shift in the absorption. Therefore, from the spectroscopicresults, we know that these three kinds of pH probe could be used in biologicalanalysis.In Chapter Ⅲ, A new fluorescence turn-on and highly sensitive Hg2+chemodosimeter have been designed by introduced alkyne and thiol moieties intoCS-NIR dyes. This probe exhibits high selectivity, fast response to Hg2+, lowdetection limit and anti-interference ability. The probe also exhibited a largefluorescence enhancement by the interactions with Hg2+. The appropriateamphipathicity of probe ensured the cytomembrane penetrability and successful Hg2+imaging in the living cells. In addition, we have made the mechanism rsearch by1HNMR and MS spectrometry, the results showed that the interaction between probe andHg2+was catalytic cyclization.In Chapter Ⅳ, Based on the displacement approach strategy, a new turn onfluorescent sensor for Hydrogen sulfide was constructed on the base ofphenanthroimidazole and8-hydroxyquinoline ligand. Relatively large fluorescenceturn-on signal in tris-HCl media, high selectivity, high sensitivity, and the ability towork well in a wide pH range. The design of replacement strategy by copper ionquenching of fluorescence and fluorescence recovery from sulfur anions will can bewidely used in the development of other anionic sensors.