| Metal-Organic Frameworks（MOFs）,also known as porous coordination polymer,is a kind of highly porosity organic-inorganic hybrid materials.MOFs always constructed by the central metal ions/clusters and functional organic linkers through self-assembly methods.At present,MOFs showed explosive development due to their high specific surface area,tunable functional ligands,diverse topologies,and porous properties in the fields of gas storage,drug delivery,bioimaging,photocatalysis and chemical sensing.Four kinds of MOFs materials were synthesized by solvothermal method based on the transition metal ions Zn（II）,Mn（II）and nitrogen-containing organic ligands（pyrazine-2,3-dicarboxylic acid（H2L）,1,10-phenanthroline（phen）,2,2’-bipyridyl-4,4’-dicarboxylic acid（H2BPDC））.The structure and properties of MOFs were characterized by X-ray single-crystal diffraction（XRD）,atomic force microscopy（AFM）,infrared spectroscopy（IR）and thermogravimetric analysis（TGA）,and their applications in electrochemical/fluorescence sensing were further studied.The contents are mainly divided into the following three parts:1.3D Zn-MOF:{[Zn（BPDC）·（H2O）2]}n（Zn-1）was synthesized based on organic ligand H2BPDC and central metal ion Zn（II）by hydrothermal method.Due to its excellent electrochemical activity and solvent stability,Zn-1 can be modified on to the surface of glassy carbon electrode（GCE）to prepare an electrochemical sensor,Zn-1/GCE.The sensor can be applied for sensitivity detecting m-dinitrobenzene（m-DNB）in phosphate buffer solution（PBS,p H=8.0）with a detection of limit 2.11μM.In addition,Zn-1 has excellent luminescence performance.It can be uniformly dispersed in N,N’-dimethylformamide（DMF）to prepare Zn-1 luminescence sensor（Zn-1/DMF）for detecting m-DNB.M-DNB can promote the fluorescence quenching of Zn-1 and the quenching efficiency was 81.5%.Besides,Zn-1/DMF can still recognize the m-DNB in aqueous solution even in the presence of multiple organic compounds.Zn-1 has achieved dual-function detection of m-DNB in electrochemical and fluorescent methods.2.1D Zn-MOF:{[Zn（HL）2]·（C3H8）2·（H2O）}n（Zn-2）was synthesized based on H2L and Zn（II）by solvothermal method.Due to Zn-2 has high air/solvent stability and electrochemical activity,it was dropped on to a GCE surface to assemble an electrochemical sensor,Zn-2/GCE.It was used for selectively detecting nitroacetophenone isomers.Zn-2/GCE can specifically recognize 2’-nitroacetophenone（2’-Nap）and 4’-nitroacetophenone（4’-Nap）with a detection limit of 0.746μM and 1.47μM,respectively.On the contrary,it had no specific recognition for 3’-Nap.Besides,due to its excellent fluorescence property,Zn-2 can be uniformly dispersed in isopropyl alcohol（IPA）for detecting nitroacetophenone isomers.The fluorescence quenching efficiency of 2’-Nap,3’-Nap and 4’-Nap on Zn-2 were92.3%,93.6%and 98.9%,respectively.3.2D isostructural Zn-MOF and Mn-MOF:{[M（phen）（L）]·H2O}n（M=Zn,Mn）,namely Zn-3 and Mn-1,were synthesized by hydrothermal methods.Zn-3 and Mn-1 have excellent thermal/solvent stability and high electrochemical activity,they were used as electrochemical sensors materials to prepare Zn-3/GCE and Mn-1/GCE sensors.Zn-3/GCE has specific recognition for nitroaniline isomers（2-NA,3-NA and 4-NA）,and the detection limits were 9.30μM,7.95μM and 5.36μM,respectively.Beside,Mn-1/GCE can specifically recognize nitrobenzyl alcohol isomers（2-NBA,3-NBA and 4-NBA）,and the detection limits were 7.02μM,11.6μM and 14.2μM,respectively.In addition,Zn-3 has excellent luminescence properties for identify detecting NA isomers in aqueous solution,and the fluorescence quenching efficiency of 2-NA,3-NA and 4-NA for Zn-3 were 70.51%,40.01%and 79.86%,respectively. |
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