Syntheses Of Novel Benzothiazole Derivatives And Studies In Their Spectroscopical Responses To Analytes

In view of their good fluorescence properties,benzothiazole derivatives are developed and widely used for recognizing ions or small molecules as fluorescent probes.In this dissertation,seven benzothiazole derivatives were designed and synthesized as candidates of fluorescent probes,three of them R1-R3 were studied in aspects of their responses to metal ions,anions or small molecules with spectroscopic methods.The main contents are as follows:1.Fluorescent probe R1 was synthesized using 2-(2 '-hydroxyphenyl)benzothiazole and rhodamine 101 hydrazine as starting materials.It was characterized by spectra of NMR,MS and IR.The recognizing properties of R1 to the paramagnetic metal ions of Cu2+,Co2+and Ni2+were studied respectively.The experimental results showed that in pH=7.4 PBS buffer solution:ethanol=4:6(v:v),the paramagnetic metal ions Cu2+,Co2+and Ni2+could be well recognized and distinguished by using fluorescent probe R1.It could be observed that when ?ex=350 nm,in presence of Cu2+,Co2+or Ni2+,and the fluorescence intensity of R1 decreased at 565 nm and increased at 460 nm.At the same time,new absorption peaks appearing at 450 nm and 583 nm could also be observed,while the absorbance of its original absorption peak at 370 nm was gradually decreased.The high sensitivity of R1 in detection Cu2+,Co2+ or Ni2+ was realized,and the detection limits reached the level of nanomole.Moreover,R1 could be used as a fluorescence ratio probe in detection of Cu2u,Co2+and Ni2+,which had better abilities to resist environmental interference compared with the general fluorescence probes with a single emission wavelength.2.Fluorescent probe R2 was synthesized by using 2-(2'-hydroxyphenyl)benzothiazole and 1-naphthol hydrazine as raw materials.It was characterized by spectra of NMR.Its aggregation induced luminescence effect(AIE)and the recognition properties of R2 toward Zn2+,Cu2+,Co2+,Ni2+ CH3COO-and H2PO4-were studied respectively.In ethanol:water=7:3(v:v),Zn2+,Cu2+,Co2+,Ni2+,and CH3COO-,H2PO4-could be well identified and distinguished by R2.After the addition of Zn2+,the fluorescence intensity of probe R2 increased by 12 times at 488 nm,and the absorption spectrum showed an increase of 429 nm and a decrease of 365 nm.However,after the addition of Cu2+,Co2+or Ni2+,the fluorescence of probe R2 were quenched at 578 nm.And the fluorescence intensity was increased at 550 nm after the addition of CH3COO-or H2PO4-.The ultraviolet-visible absorption spectrum showed an increase of 500 nm and a decrease of 365 nm in presence of CH3COO-or H2PO4-.At the same time,the probe also had a series of advantages such as fast responses,low detection limits and good anti-interference performances.3.Fluorescent probe R3 was synthesized by using 1-(2-benzo[d]thiazolyl)-2-naphthol and 4-chloro-7-nitrobenz-2-oxa-1,3-diazole as raw materials.It was characterized by NMR and IR.The spectroscopical properties of R3 were studied in presence of H2S2,cysteine,homocysteine or glutathione respectively.The experimental results showed that in DMSO:water=7:3(v:v),R3 was able to identify and distinguish S22-from amino acids containing sulfur.after addition of S22-to solutions of probe R3,new absorption peak at 561 nm in the absorption spectra appeared.New absorption peaks of probe R3 appeared at 481 nm with the addition of cysteine and homocysteine respectively,and new absorption peak of probe R3 appeared at 427 nm with the addition of glutathione.After S22-was added to the solutions of probe R3,the fluorescence intensity of probe R3 enhanced at 468 nm when excited from 370 nm.New emission peaks probe R3 in presence of cysteine,homocysteine and glutathione respectively appeared at 467 nm when excited from 370 nm.At the same time,new emission peaks probe R3 in presence of cysteine,homocysteine respectively appeared at 550 nm.In addition,In combined with S22-and thiol amino acids respectively,R3 showed different colors.After the addition of S22-,the reaction solution became purple.When cysteine was added,the reaction solution became orange.The solution became yellow in presence of homocysteine.When glutathione was added,the solution became light yellow.Therefore,it had the advantages as a naked eye probe.At the same time,the spectroscopical measurements also showed that probe R3 had strong anti-interference abilities toward S22-and thiol amino acids and was stable under weak acid and neutral conditions.