Design, Synthesis And Spectra Study Of Fluorescence Probes Based On Chemical Reaction For Anions

Recognition and sensing of anions have received considerable attention for their important roles in biological, industrial, and environmental processes. Among the anions, cyanide anion and bisulfite anion have been widely used in the production practice, but they are detrimental anions causing poisoning in biology and the environment. Thus, there exists a need for efficient sensing systems for cyanide and bisulfite to monitor them from contaminant sources. However, the traditional probes that relied on hydrogen-bonding, namely the use of hydrogen-bonding of different ways and the difference between the target anion shapes and other anionic charge density to achieve selective recognition have generally displayed weak selectivity relative to other anions. To overcome this limitation, reaction-based receptors for anions, which were taken advantage of some of them nucleophilic character, have been developed recently. In this thesis, the reaction site and the fluorophore were combined together to design and synthesize new chemical sensing probes. These fluorescent probes are based on benzo [e] indolium, and have been investigated for detecting cyanide and bisulfite in water solution and PBS buffer solution, respectively. The results showed that these probes possess high selectivity and sensitivity for target anions. Absorption and emission spectra were recorded to study the performance of these sensing probes by a UV-vis spectrophotometer and a fluorescence spectrometer, respectively. The data from NMR and ESIMS were employed to prove the adding mechanism.A detailed overview of the concept and mechanism of the fluorescence sensing probes and research development of fluorescence probes based on chemical reaction at home and abroad have been summarized.A fluorescence enhancing cyanide probe2-1, a fluorescence enhancing bisulfite probe3-1and a ratiometric fluorescent probe4-1were designed and synthesized. The sensibility of probe2-1for cyanide was performed in100%aqueous solution. The detection of cyanide was performed via a1,2-addition reaction, resulting in a prominent fluorescence enhancement and an obvious color change. The probe shown a highly selectivity in water and could be performed in a range of pH value between6and9. A simple paper test strip system for the rapid monitoring of cyanide in a short time at low concentrations was developed. Probe3-1was invested in PBS buffer and it possessed high selectivity and sensitivity for bisulfite. The detection of bisulfite was performed via a1,4-addition reaction and produced bright fluorescent. Moreover, the practical value of the probe was confirmed by application to detect the lever of bisulfite in sugar samples and cells. The probe4-1showed fluorescence ratio change both on cyanide ions and bisulfite. The detection of cyanide was in water. It was performed via a1,2-addition reaction then blocked the intramolecular charge transfer process that produced fluorescence ratio change. It also could be used in the paper test strip system. The detection of bisulfite was in PBS buffer. The bisulfite undergoes1,4-addition reaction, resulting in a fluorescence ratio change and a significant change in fluorescence. A simple paper test strip system was developed to detect cyanide and bisulfite rapidly. Moreover, the probe was used to detect bisulfite in real samples with good recovery.A series of fluorescent probes was synthesized on the basis of previous work, and displayed satisfied results. However, some further research is still needed to improve the probe. Finally, some suggestion was stated for the future work.