The Applications Of Novel Probes Based On Rhodamine And Tetraphenylethylene Derivatives

Due to its high sensitivity, high selectivity, fast analysis with spatial resolution for providing in situ and real-time information, and nondestructive sample preparation, the fluorescent probe method seems to be an ideal candidate for both sensing and bioimaging metal ions, anions and small molecules in various samples. As a consequence, in the past two decades, a greatly increasing interest was focus on the development of "turn-on" small-molecule fluorescent probes. Among them, probes which exhibit signal emission susceptible to interference by various factors, such as errors from the instruments, changes of the detective system and the environment and human errors. The ratiometric fluorescent probes allow the measurement of changes of the intensity ratio at two emission bands induced by analytes and provide built-in correction for the above-mentioned environmental effects. Therefore, searching for novel "turn-on" and ratiometric probes to be applied in real samples and biological samples, remains task of theoretical and practical significance.Taking the above-mentioned research hotspots, to build probes based on AIE and TBET, the contents of this thesis are presented as follows:1. In Chapter2, based on the advantages of aggregation induced emission of tetraphenylethylene, we designed and synthesized a novel compound (DEDA-TPE) for the detection of aluminium ion. Among several common soluble organic solvents, DEDA-TPE showed the highest sensitivity to Al3+in a system of water/ethanol, so we chosed the system for further detecting. In the solution of Vwater/Vethanol=1:9, the probe showed high selectivity towards aluminum ion. Job’s plot showed that the complex of DEDA-TPE and Al3+exhibited a maximum fluorescence emission at485nm, when the molecular fraction of Al3+was closed to0.5. This indicated that a1:1stoichiometry is possible for the binding mode of DEDA-TPE and Al3+. The the aggregation were verified by the dynamic light scattering (DLS) and the scanning electron microscope (SEM), with an Al3+concentration-dependent size observed.2. In Chapter3, based on the advantages of aggregation induced emission of tetraphenylethylene, we designed and synthesized a novel compound (TSB-TPE) for the detection of Zn2+. It was found that water and DMF was the best solvent for the Zn2+-triggered aggregation of TSB-TPE with the highest sensitivity compared with other solvents, so we chosed the system for further detecting. In the solution of Vwater/VDMF=1:9, the sensor showed high selectivity towards Zn2+. Job’s plot It showed the complex of TSB-TPE and Zn2+exhibited a maximum fluorescence emission at485nm, when the molecular fraction of Zn2+was closed to0.3. It indicated that a1:1and1:2stoichiometry are possible for the binding mode of TSB-TPE and Zn2+. The aggregation was verified by the dynamic light scattering (DLS) results, with a Zn2+concentration-dependent size observed.3. In Chapter4, we designed and synthesized a novel a coumarin-rhodamine (CR) through bond energy transfer (TBET) system and demonstrated that TBET was a convenient strategy to design an efficient ratiometric fluorescent bioimaging probe for metal ions. Such TBET strategy is also universal, since no spectral overlap between the donor and the acceptor is necessary, and many more dyes than that of FRET could be chosen for probe design. As a proof-of-concept, Hg2+was chosen as a model metal ion. By combining TBET strategy with dual-switch design, the proposed sensing platform shows two well-separated emission peaks with a wavelength difference of110nm, high energy transfer efficiency of97.4%, and a large signal-to-background ratio of697.7, which affords a high sensitivity for the probe with a detection limit of7.0nM for Hg2+. The proposed chemosensor has been used for direct measurement of Hg2+content in river water samples and imaging of Hg2+in living cells with satisfied results.