Synthesis And Analysis Of Coumarin-fluorescent Probes

Chapter 1:The chapter 1 mainly shows mechanism of how fluorescence produces and various factors will affect it. Then four mechanism, such as photoinduced electron transfer and intermolecular charge transfer that will be referenced in actual research, are introduced. Moreover, we review the studying condition and analytical applications of coumarin-fluorescent indicator in cations,anions and neutral particles.Chapter 2:A probe,6-[bis-(2-acetoxyethyl) aminomethyl]-4-methyl ;oumarin, was synthesized. First,4,6-dimethyl coumarin was prepared via pechmann reaction from o-phenylenediamine and p-cresol, then it reacted with NBS to produce 6-bromomethyl-4-methyl coumarin and next with diethanolamine to produce 6-diethanolaminomethyl-4-methyl coumarin. Last, the products esterificated with acetyl chloride to give the probe compound. A convenient experimental condition was chosed to give a higher yield.The structure was characterized by 1H NMR and the UV absorption of probe compound in different organic solvents was also investigated, results showed that UV spectrum was little influenced by solvents. We studied the fluorescent properties in the case of injecting cations and fought that Fe3+ and Cu2+ responded better to the probe.Chapter 3:Another probe compound,4-(trans-4-methylformate-styryl)-6-[bis-(2-acetoxyethyl) aminomethyl]-coumarin, which has a bigger conjugated space was synthesized based on chapter 2. A convenient experimental condition was chosed to give a higher yield. The structure was characterized by 1H NMR, and investigated it's UV absorption to find that solvents made little influence on the spectrum. We also studied fluorescent spectrum of the probe compound when injected cations, the probe behaved more selective to Fe3+ and the fluorescence intensity became weaker more or less when different cation was added. Chapter 4:2-Methyl-benzimidazole, a group with strong fluorescent emission, was used to react with 4-formyl-6-methyl coumarin and produced a novel compound, Trans- 4- [2- (benzimidazole-2 substituted) vinyl]-6-methyl coumarin. The structure was characterized by 1H NMR and IR respectively. We detected the UV spectra and fluorescent spectra of the new compound in different organic solvents, the results showed that solvents may influence it's absorbance and fluorescence intensity.Chapter 5:Compare with previous literature and experimental facts to explore the factors may affect the fluorescence properties of fluorescent probes and coumarin derivatives. We find that groups with different properties and conjugated system are the factors we must concern when design a coumarin probe.