Fluorescent Probes For Hydrogen Sulfide And Sulfur Dioxide Derivatives

Since the fluorescent indicators for the calcium ion were reported by in the early 1980s,fluorescent probes have been widely applied in biological,medical,environmental science because of sensitivity,selectivity,simplicity and no damage toward samples.Nowadays it has been a hot research field of developing new fluorescent sensors.Hydrogen sulfide?H₂S?and sulfur dioxide?SO₂?are reactive species which contain sulfur,belong to reactive sulfur species?RSS?.H₂S can exist as a foul-smelling gas or dissolved in aqueous solution,primarily as the mono-anionic form,HS^-.H₂S and other reactive sulfur species?RSS?contribute to a broad array of physiological responses to maintain cellular health.RSS are active as antioxidants and signaling agents in a variety of tissue types,including the liver,gastro-intestinal system,pancreas,brain,and circulatory system.studies have established that unregulated,abnormal levels of H₂S may contribute to disease,as observed in models of Huntington's,Parkinson's,and Alzheimer's diseases.Sulfur dioxide?SO₂?is a well-known air pollutant,which was produced by burning fossil fuels containing sulfur.However,more recent work has shown that this molecule is generated endogenously,mainly from sulfur-containing amino acids through biosynthetic pathways.SO₂ exhibits unique bioactivities such as vasodilatation and lowering of blood pressure.These observations have led to speculation that SO₂ can be considered a gasotransmitter.Thus,it is important to develop specific fluorescent probes for these gastransmitters.In chapter 2,by importing azide group to amino phenylanthocyanin,we exploit a specific fluorescent probe 2-1 for the detection of H₂S.Compared with other ions,biothiols and reactive oxygen species,the probe dispalys favorable selectivity towards H₂S.In DMSO-PBS?10 mM,pH7.4,1:1,V/V?buffer,probe 2-1 reacts with H₂S which azide group is reduced to amino group,producing fluorescence enhancement.The detection limit is 7.65×10^-8mol/L.In chapter 3,a fluorescent probe for sulfur dioxide derivatives has been exploited based on the nucleophilic addition with double bound.Probe 3-1has strong fluorescence.Upon reacting with HSO₃^-,the conjugation has been destroyed which quenching the fluorescence.Probe 3-1 has strong fluorescence in varied pHs.Whereas the production of addition with HSO₃^-has weak fluorescence in the range of pH 7-10,which indicates probe 3-1 is suitable for the detection of HSO₃^-in basic and physiological environment.