Development Of Quinolinium-Based Novel Phosphorescent Materials And Fluorescent Probe

Phosphorescence and fluorescence are widely used in sensing and biological detection. Phosphorescence is a spin-forbidden electronic transition and the decay rate is very low. As a result phosphorescence is easily quenched at room temperature due to various, more rapid thermal decay pathways. Since the discovery of phosphorescent materials, complexes containing heavy metals have mostly dominated, but nowadays people want to find high efficiency, low toxicity, and pure organic phosphorescent dyes. Fluorescent probe is widely used in biological detection because of its high sensitivity and selectivity. At present, only a few of fluorophores can be used in fluorescent probe and it’s high cost. Development of low cost, high efficiency fluorescent probe is very significance.Chapter 1 mainly contains two parts. The first part includes the basic principle of phosphorescence, room temperature phosphorescence materials, design principles of room temperature phosphorescence materials. The second part includes the the application of fluorescent probe in enzyme detection, summary the existing fluorescent probes on β-Galactosidase and lipase, summary and analysis of the principle of fluorescent probeChapter 2, We synthesized 9 kinds of quinolinium and its derivatives and measured their spectra and emission lifetimes at room temperature and 77K. The results show that they exhibit room temperature phosphorescence and different counter ions have an impact on molecules’light emission. These results guide us to extrapolate that the counter ions in the system do not only serve as heavy atoms which induce triplet generation, but also work as electron donors which affect spectroscopic properties of the system.Chapter 3, We synthesized a novel β-Galactosidase ratiometric fluorescence sensing (RFS) based on Excited-state Proton Transfer(ESPT). We combined 6-hydroxyquinolinium with β-Galactosidase substrates by a covalent bond. When β-Galactosidase interaction with the probe, the fluorophore will be released. It exhibits a dramatic colour change (deep blue to red) and possesses a huge response ratio (over 2000 fold) upon specific regconition of target enzymes.Chapter 4, We synthesized a novel lipase ratiometric fluorescence sensing (RFS) based on Excited-state Proton Transfer(ESPT). We synthesized different length of carbon chain probes, through the enzyme kinetics analysis, we screen out the optimalizing probe. We found that, probe with longer carbon chain has a stronger interaction with enzyme.