Construction And Fluorescence Sensing Of Amino-functional MOFs Material

Metal–organic frameworks（MOFs）are a class of porous hybrid materials formed by the self-assembly of organic ligandsand metal ions.MOFs exhibit excellent properties such as ultrahigh surface area,tunable porosity,and modifiable chemical functionality,and have been widely applied in various fields such as gas storage/separation,molecular recognition,chemical sensing,catalysis and drug delivery.In this papers,three kinds of fluorescence probes based on amino-functionalized MOFs were developed,which was successfully applied to detect hypochlorite（Cl O^-）,glutathione（GSH）and the anthrax biomarker aipicolinic acid（DPA）.The detailed studies are as follows:（1）Amino-functionalized copper-based metal–organic frameworks（NH₂-Cu-MOFs）were synthesized using NH₂-BDC as the organic ligand,Cu²⁺as the metal source and polyvinyl pyrrolidone（PVP）as a binder by a one-pot hydrothermal method.NH₂-Cu-MOFs exhibited the excellent fluorescence performance and were developed as a novel fluorescent probe for high sensitivity and fast detection of Cl O^-.Moreover,the NH₂-Cu-MOFs were successfully applied to analyse Cl O^-in real water samples.（2）The NH₂-UiO-66 was synthesized where 2-amino-terephthalic acid as the organic ligand and Zr⁴⁺as the center metal ions.Based on the metal enhanced fluorescence of Ag NPs,we developed the NH₂-Ui O-66@Ag NPs.Moreover,in the present of GSH,the fluorescence of NH₂-Ui O-66@Ag NPs was quenched via electrostatic interaction and Ag-S reaction.The present sensing strategy shows good linear relation with the concentration of GSH in the range of 0.2-1.0μM and 1.0-30μM,and the limit of detection are 79 n M.Furthermore,our fluorescent nanosensor was utilized to detect GSH in human serum with a recovery of 96.8%-102.5%.The results indicated that NH₂-Ui O-66@Ag NPs is successfully applied for high sensitive and selective detection of GSH in human serum.（3）A dual-ligand MOFs material Ui O-66-（COOH）₂-NH₂ was synthesized where1,2,4,5-benzenetetracarboxylic acid and 2-aminoterephthalic acid as the organic ligand and Zr⁴⁺as the center metal ions by hydrothermal method Then,Ui O-66-（COOH）₂-NH₂ had abundant carboxyl,which can firmly grasp Eu³⁺ions to form Eu³⁺doped MOFs material(Ui O-66-（COOH）₂-NH₂/Eu by the unsaturated coordination of Eu³⁺with the carboxyl group.The Ui O-66-（COOH）₂-NH₂/Eu has a ligand-based emission at 453 nm,which is attributed to NH₂-BDC.Upon addition of DPA,the fluorescence peak at 453 nm is quenched due to energy-transfer.Meanwhile,the fluorescence of Eu³⁺can be sensitized due to the presence of energy transfer from DPA to Eu³⁺when DPA chromophore coordinated with Eu³⁺.The method revealed a good linear relationship of F₆₂₁/F₄₅₃value with DPA concentrations over the range0.2–40μM and the limit of detection is 25.0 n M.In addition,the ratiometric fluorescent sensor displayed an obvious color variety from blue to red.Relying on its identifiable color change,on-site assays based on smartphones are established for the visual detection of DPA.The method provided a promising method for the qualitative and semi-quantitative detection of DPA on-site.