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Study On Synthesis And Properties Of Novel Spiropyran Photochromic Materials

Posted on:2022-06-23Degree:MasterType:Thesis
Country:ChinaCandidate:D ZhangFull Text:PDF
GTID:2481306494477144Subject:Chemical Engineering and Technology
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The spiropyran photochromic material,which has the advantages of fast response speed,high thermal stability,and good fatigue resistance,can be used as colorimetric and/or fluorescent probes for metal ions,etc.However,the spiropyran-based probes are capable for detection of fewer analytes and exhibit poor selectivity and anti-interference ability.This paper designs to introduce hydroxyethyl,morpholinyl or 3-chloro-2-hydroxypropyl groups into the spiropyran structure to synthesize new high-efficiency metal ions and pH probes.In addition,a copolymer containing spiropyran is designed and synthesized as a sensitive material that can respond to various stimuli such as light,pH,and biological thiols.The main content of the thesis includes the following parts:The first part is the synthesis and structural characterization of new spiropyran small molecule compounds SP1,SP2,SP3,SP4,SP5,SP6 and SP7.N-allyl spiropyrans SP1 and SP2,N-(?-hydroxyethyl)spiropyrans SP3,SP4 and SP5,N-benzyl spiropyran SP6 and N-(3-chloro-2-hydroxypropyl)spiropyran SP7 were synthesized by N-alkylation and other reactions.Among the new compounds SP3 and SP4 also bear a morpholino group.The yields of the synthesized spiropyran compounds are 35%?92%.The structures of spiropyran compounds were characterized by means of 1H NMR,13C NMR,MS and IR spectra.The second part is the research on the recognition performance of spiropyran compound SP2.The spiropyran compound SP2 was prepared by the reaction between amino spiropyran and maleic anhydride.SP2 contains amide and carboxyl group in its structure and can be used as a water-soluble fluorescent probe to detect Fe3+and pH.Upon addition of equivalent different metal ions(Li+,Na+,K+,Ag+,Cu2+,Fe2+,Zn2+,Co2+,Ni2+,Mn2+,Sr2+,Hg2+,Ca2+,Mg2+,Al3+,Cr3+,Fe3+)to SP2 solution(20?M)in DMF/H2O(9:1),it was found that the fluorescence intensity of the probe SP2 decreased by 2.4 times after adding Fe3+while addition of other metal ions did not cause remarkable change in the fluorescence intensity,indicating that SP2 can be used as a fluorescence turn-off probe to detect Fe3+ions.Probe SP2 presents different colors at different pH values.When pH is 1?3,it is light yellow;when pH is 4?9,it is yellow-brown;when pH is 10?13,it is purple and when pH is 14it is colorless.Therefore,SP2 can be used as a colorimetric probe for detecting pH.The third part is the research on the recognition performance of spiropyran compound SP6.After adding different metal ions to SP6 solution,Fe2+can increase the fluorescence intensity of SP6 by about 36 times;Mg2+and Co2+can slightly increase the fluorescence intensity of SP6 while addition of other metal ions does not cause significant change in the fluorescence intensity.Therefore,SP6 can be used as a fluorescence turn-on probe for detecting Fe2+ions in ethanol/water(9:1)system.The detection limit for Fe2+detection is 0.76?M.Investigation of the effect of pH on Fe2+detection by probe SP6 revealed that the fluorescence intensity of SP6 containing Fe2+did not change much with pH in an acidic environment,indicating that pH has almost no effect on the detection of Fe2+by probe SP6.Other common metal ions including Li+,Na+,K+,Ag+,Cu2+,Zn2+,Co2+,Ni2+,Mn2+,Sr2+,Hg2+,Ca2+,Mg2+,Al3+,Cr3+,and Fe3+did not cause significant interference with Fe2+fluorescence recognition.The color of probe SP6 solution varies with pH.It is yellow when pH is 1?2 and colorless at other pH values.The fluorescence intensity of probe SP6 is relatively low when pH is 1?12 and does not change much with pH.When pH increases to 13 and14,the fluorescence intensity increases rapidly.Therefore,SP6 can be used as a colorimetric and fluorescent probe for detecting pH.The fourth part is the synthesis,characterization and performance study of the spiropyran copolymer.Tercopolymer C was prepared by using azobisisobutyronitrile(AIBN)as initiator through free radical polymerization of N-allyl spiropyran monomer,4-phenyl-7-allyloxycoumarin and butyl acrylate.The number average molecular weight and weight average molecular weight of the spiropyran-containing polymer C measured by GPC method were 2985 and 2360,respectively,and the PDI was 1.26.Polymer C is easily soluble in acetone,soluble in ethanol and ethyl acetate,and insoluble in water and toluene.After adding Fe3+and Fe2+to polymer C solution in DMF/H2O(1:9),the fluorescence was quenched.While addition of other common metal ions did not bring about obvious changes in the fluorescence intensity.Therefore,polymer C can be used as a fluorescence turn-off probe to detect Fe3+and Fe2+ions.The limits of detection for Fe3+and Fe2+are 0.27?M and 0.14?M,respectively.
Keywords/Search Tags:Spiropyran, photochromic, fluorescent probe, metal ion, pH
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