Preparation And Sensing Application Of Function-oriented Spiropyran Compounds

Spiropyran compounds are photochromic compounds with great stability and reversability.With irradiation of certain wavelengths and intensities,the reversible switching occurs between the colorless form-ring closed spiropyran?SP?and colored form-ring open merocyanine?MC?.Because of the photochromic properties,spiropyran-based compounds have attracted great attention.In this thesis,two spiropyran-based molecular probes were designed and synthesized with specific functionalization.The application of the spiropyran-based molecular probes for the detection of biomolecules and metal ions was also explored.The main contents and conclusions of this thesis are as follows:Chapter 1:This chapter started with the brief introduction of the photochromic compounds and their classification,application as well as the prospect,and then,it followed with the asummary on the structures,properties,and syntheses of spiropyran compounds,together with the factors affecting the photochromic properties.Their application in the analysis and detection,as well as the construction of drug carrier systems was also presented.Finally,it outlined the background,main contents and innovations of this thesis.Chapter 2:This chapter described the synthesis of spiropyran-based probewiththemodificationofhydroxypropyl-?-cyclodextrin?HP-?-CD-SP?.The spiropyran-based probe was able to selectively detect GSH by colorimetry.When mixing the solution of HP-?-CD-SP with amino acid,and keeping in the dark for 1 hour,the color of the mixed solutions changed from colorless to pink except the one with GSH.The selective response of the probe towards GSH arised from inhibiting the formation of colored isomers,rather than the electrostatic attraction between the amino acid and the merocyanine structure.This study achieved a selective detection of GSH by suppressing the isomerization between the colored and colorless form,and provided a new idea for the development and research of novel spiropyran probes.Chapter 3:In this chapter,an 8-aminoquinoline-functionalized spiropyran fluorescent sensor?8-AQ-SP?was successfully synthesized for the detection of Fe?III?with the detection limit of 1.20 x 10^-8 M.The binding with Fe?III?significantly quenched the fluorescence of 8-AQ-SP probe,but the fluorescence emission remained almost unchanged with the binding of other metal ions such as K?I?,Hg?II?,Mg?II?,and Na?I?.To verify the selective and quantitative determination of Fe?III?,the interference experiment with other coexisting ions was also conducted and showed no interference.The binding ratio between 8-AQ-SP probe and Fe?III?was determined as 1:1 by using Job's plot.The binding constant of8-AQ-SP probe to Fe?III?was determined from the Benesi-Hildebrand plot as 4.02 x 10³ M^-1.Chapter 4:This chapter recapitulated all work done in this thesis,and raised some problems based on the current results,as well as some proposals for future development.