Synthesis, Application And Spectra Study Of Chemical Reaction Based Fluorescent Probes

As a kind of recognition and sensing molecular tools, fluorescent probes have been successfully applied to the ions and molecules detection and cell imaging, which have received the widespread attention of scientists. These type probes have been widely used due to its high selectivity, high sensitivity and fast response time of detection. Cyanide and bisulfite play an important role in the daily life and production practice, but unreasonable use and disposal can produce serious harm to the environment and human health. Therefore, it is very important to design and synthesize some fluorescent probes with high sensitivity and selectivity for the cyanide and bisulfite detection. In this thesis,based on the summarizing predecessors work, three types of fluorescent probes for cyanide and bisulfite detection in different conditions were designed and prepared. The fluorescent spectra and UV-vis spectra recorded the recognition performances and sensing mechanisms. Besides, the application of these probes in test papers and cell imaging were then evaluated. The main contents are as follow:The recognition mechanism of anion and fluorescent probes was elaborated and current research development of cyanide and bisulfite fluorescent probes were summarized in the first chapter.A cyanide fluorescent probe 2-1 based on aggregation-induced emission mechanism was introduced in the second chapter. The probe was synthesized by2,2’:5’,2”-terthiophene-5-carbaldehyde and benzo [e] indolium and showed a high selectivity and sensitivity toward cyanide in water solution. A 1,2-addition reaction happened between the cyanide and probe 2-1, resulting the molecular aggregation and a bright yellow fluorescence, which was further studied by the dynamic light scattering and scanning electron microscopy. The reaction could be completed in 30 s, the detection limit was 0.1 μM, far lower than the world health organization’s maximum 1.9 μM. Nuclear magnetic titration and high resolution mass spectrometry demonstrated the mechanism of the reaction, the filter paper and cell test researched its application.A cyanide fluorescent probe 3-1 based on terthienyl was illustrated in the third chapter. In DMSO : H2 O = 9:1( V/V) system, the probe showed the excellent recognition for cyanide. The reaction could be accomplished in 5 min,the detection limit was 0.1 μM. The reaction between probe 3-1 and cyanide blocked the intramolecular charge transfer process and produced bright green fluorescent.An A-π-A’ bisulfite ratio fluorescent probe 4-1 based on benzo [e] indolium was displayed in the fourth chapter. The detection of bisulfite was in PBS buffer.Nuclear magnetic titration and high resolution mass spectrometry confirmed that the probe and bisulfite undergone a Michael addition reaction, leading the fluorescent emission peak gradually weaked at 578 nm, and the fluorescent emission peak gradually enhanced at 466 nm, a notable fluorescent ratio change.And the color changed from orange red to blue under the UV light. The reaction could be finished in 30 s, the detection limit was 15 nM, which showed a satisfactory selectivity and sensitivity. A simple paper test strip system was developed to detect bisulfite rapidly. Moreover, the probe was used to detect bisulfite in sugar samples and cells.In the fifth chapter we concluded some summarizations and suggestions about the next work.