Research On New Functional Fluorescent Dyes Based On Rhodamine And Coumarin Derivative

The activity of life is an effect of different chemical reactions by lots of biological active substances, including metal ions and small active molecules. In recent years, fluorescent technology has been widely used in bioimaging, biosensing, medical diagnosis and environmental detection. The fluorescence-enhanced signal can avoid the interference well, and the fluorometric methods based on energy transfer have attracted more attentions. Among these talent fluorophores, because of the good photostability and easy to modify, rhodamine and coumarin derivative have been more and more used in the biological experiments.Designed and synthesized a new type of Rodamine B derivative D2. As a specific probe for Cu2+in aqueous solution, the detection process was not effect by other ions. The color change reduced by1×10-6mol/L Cu2+still can be seen by naked eyes. The binding process of the probe and the Cu2+is reversible. D2has potential application for detection Cu2+in the actual environment for rapid real-time analysis.Rosamine derivative RC-1, bearing macrocyclic ligand [15]aneNO2S2as receptor, was synthesized as an enhanced fluorescent chemosensor for Ag+in absolute aqueous solution. The detection limit was9.3×10-8mol/L. The fluorescence images in living cells show the potential application of RC-1. The difference of fluorescence enhancement process after binding with Ag+/Hg2+in acetonitrile/water solution was first clarified by theoretical calculations.A novel molecule T1with efficient intramolecular charge transfer was designed as a fluorescent chemodosimeter for cysteine (Cys) and homocysteine (Hcy). Upon addition of Cys/Hcy, T1exhibited greatly enhanced fluorescence intensity as well as a large absorption peak shift (70nm), and can be used for bioimaging of Cys/Hcy in living cells and detection in human plasma by visual color change. The detection mechanism was clarified by’H NMR, mass spectrometry analysis and Gaussian calculations.A couple of fluorescent tools bearing rhodamine B and aza-coumarin groups have been synthesized as selective and quantitative probes for Cu2+. Based on FRET mechanism, compounds T1RB-1and T1RB-2exhibited selective changes in the absorption and emission spectra towards Cu2+ion over miscellaneous cations. Interesting, the different electron density and structure geometry make chemosensor T1RB-2, which has C-N in the structure could bind with Cu2+, simultaneously with Cu+, that was not like probe T1RB-1with C=N. T1RB-2 could penetrate the membrane and detect Cu2+by ratiometry imaging in living cells. The probe T1RB-2also exhibits subcellular localized fluorescence staining of lysosome.The coumarin/naphthalimide-rhodamine cassettes were constructed through a conjugated acetylene phenyl linker, which prevents the fluorophores from becoming planar, makes the energy transfer through space and through bond simultaneously. The pseudo-Stokes shifts could get to about200nm.