Study On The Detection Of Ions By Biphenylcarbonitrile-based Schiff Base Fluorescence Probe

Chapter 1:The detection mechanism of fluorescent probe and the characteristics of fluorescent probe with AIE effect are briefly introduced.Chapter 2:A colorimetric and ratiometric fluorescence probe（HIBC）was synthesized from 4-hydroxybiphenyl nitrile and aminoimidazole.HIBC interestingly exhibits an aggregation-induced emission property.HIBC can specifically recognize HSO₃^-in a nearly 100%aqueous medium.The nucleophilic addition of HSO₃^-on the imino group breaks theÏ€-electron conjugation,thereby restricting intra-molecular charge transfer（ICT）process in the probe and leading to a visual color change and observable spectral changes.HIBC shows high selectivity for HSO₃^-ions with the LOD of5.32×10^-7M.For the practical applicability,HIBC-coated paper strips were prepared for convenient,on-site detection of HSO₃^-in aqueous medium.In addition,HIBC was applied for the living He La cells bioimaging.Chapter 3:In CH₃CN/H₂O（3:2,v/v;Tris-HCl,pH=7.4）,the binding of HIBC with Cd²⁺could inhibit the isomerization of C=N and meanwhile enhance the molecular rigidity,resulting in chelating enhanced fluorescence（CHEF）.The probe has high selectivity and sensitivity for Cd²⁺with the detection limit of 1.05×10^-8M.This value is lower than the WHO drinking water standard（3μg/L）.In addition,the HIBC can be made into a test strip,and the visual detection of Cd²⁺can be realized quickly and easily.Chapter 4:A new biphenyl nitrile fluorescence probe HSBC was synthesized from 4-hydroxybiphenyl nitrile and 4-phenylsemicarbazide.By adjusting the pH value,the probe can identify and detect Zn²⁺and Al³⁺in with different fluorescence signals.In neutral and weakly acidic pH buffer aqueous medium,the probe HSBC complexed with Zn²⁺and Al³⁺at 1:1 mole ratio,giving rise to a fluorescence enhancement at 472nm and 450nm,respectively.The detection limit was 1.73×10^-8M for Zn²⁺and 3.39×10^-8M for Al³⁺,which were much lower than the allowable concentrations of Zn²⁺and Al³⁺in drinking water stipulated by WHO.In addition,the probe HSBC is capable of sensing Zn²⁺and Al³⁺in living cells.