Synthesis And Application Of Fluorescent Probes With Aggregation-Induced Emission Activity

The traditional fluorescent sensors have a common feature:they would be quenched when they aggregated. This feature limits their application as chemical and biological sensors. Aggregation-Induced Emission (AIE) compounds would not be quenched when they aggregated, oppositely, they would emit stronger light. This character makes them desirable candidates for chemical and biological sensors.Firstly, two AIE molecules containing cations or anions were synthesized, and they were used as fluorescent probes to study polyelectrolyte solutions. By regulating pH value, temperature and concentration of these AIE molecules, their physical interactions with polyelectrolytes were monitored with fluorescence spectroscopy. The experimental results indicated that they are potential probes for the investigation on the movements of polyelectrolytic macromolecules and for pH sensors to pH responsive polyelectrolytes.Secondly, an AIE compound containing hydroxyl group was synthesized. It reacted with n-heptanoic acid, dodecanoic acid, benzoic acid and cinnamic acid afforded respective esters. The obtained four esters were hydrolysised in appropriate solvents in the presence of sodium hydroxide. By taking advantage of the difference in solubility between the ester substrate and the respect hydrolytic resultant, the hydrolysis process was followed with fluorescent spectral technique. Thus the prototypical method of monitoring hydrolysis process was tentatively established.Finally, an AIE-active a-alanine ester was prepared. The hydrolysis process of this AIE-active a-alanine ester could be catalyzed by Cu2+. The experimental results showed a good relationship between the fluorescence change and Cu2+concentration, which indicated that this AIE-active a-alanine ester can be used as a fluorescent probe to specifically detect Cu2+.