The Colorimetric And Fluorescent Naphthalimide-base Probes For The Detection Of Reactive Sulfur Species

Chapter 1: In the chapter,the physiological functions,detection methods and research progress of H2 S and biothiols were reviewed.The fluorescence probes based on different reactions between probe and H2 S,biothiols were discussed in detail.On the basis of the summary of previous work,we presented our research in this thesis.Chapter 2: A new 4-hydroxy-1,8-naphthalimide-based compound(probe 1)has been designed and synthesized.The colorimetric and fluorescent properties of probe 1 towards hydrogen sulfide(H2S)were investigated in detail.The results show that the probe 1 could selectively and sensitively recognize H2 S rather than other reactive sulfur species.The reaction mechanism of this probe is an intramolecular cyclization caused by the Michael addition of H2 S to give 4-hydroxy-1,8-naphthalimide.The intramolecular charge transfer of 4-hydroxy-1,8-naphthalimide is significant.Probe1 quickly responded to H2 S and showed a 75-fold fluorescence enhancement in 5min.Moreover,probe 1 could detect H2 S quantitatively with a detection limit as low as 0.23 ?M.Chapter 3: A new N-butyl-4-amino-1,8-naphthalimide-based colorimetric and ratiometric fluorescent probe for the detection of biothiols(cysteine,homocysteine,and glutathione)was designed and synthesized.The probe exhibited good selectivity and sensitivity toward biothiols over other non-thiol-bearing amino acids and common anions with significant changes in both color(from colorless to yellow)and fluorescence(from blue to yellow-green).The mechanism is based on cleavage of disulfide by thiols followed by an intramolecular cyclization to give the product,N-butyl-4-amino-1,8-naphthalimide,which showed outstanding intramolecular charge transfer(ICT).Therefore,ratiometric fluorescence signal was observed.Furthermore,the probes were successfully applied for visualizing endogenous thiols in living cells.Chapter 4: A new N-butyl-4-hydroxyl-1,8-naphthalimide-based ratiometric and colormetric fluorescent probe was designed and synthesized,the detection for low molecular weight thiols(cysteine,homocysteine,and glutathione)were researched by UV and fluorescence spectra.The results showed that the probe can respond to low molecular weight thiols over other non-thiol-bearing amino acids and common anions with significant changes in both color(from colorless to yellow)and fluorescence(from blue to yellow-green).The mechanism is based on Michael addition followed by an intramolecular cyclization to give the product,N-butyl-4-hydroxyl-1,8-naphthalimide.The probe has good selectivity for cysteine than other amino acids attributed to faster response time.