| The rapid development of industrialization and urbanization causes a serious environmental pollution,especially the water pollution,which has been viewed as a huge threat to human health.A variety of organic(pesticides,antibiotics,and explosives,etc.)and inorganic(cationic and anion)pollutants in water enter the human body through the food chains,thus causing irreversible harm to human health.At the same time,uric acid,as a common biomarker,is not only an important product of purine metabolism,but also an important biomolecule in biological fluids such as serum and urine.Abnormal levels of uric acid in the human body indicate the presence of multiple types of disease.In addition,excess uric acid in the serum poses a significant risk to the human circulatory system.Therefore,it is urgent and of great significance to design a fast and efficient detection method for protecting ecosystems and human health.Coordination polymers(CPs),as a kind of inorganic-organic hybrid materials,are constructed by coordination bonds between metal ions and organic ligands.CPs using as chemosensors have been favored by more and more researchers due to their advantages of easy induced luminescence,high luminescence and stable structure.In addition,the larger channel and structural adjustability of CPs endows them to effectively detect the analytes.However,the self-assembly processes of CPs are affected by many factors,such as temperature,reaction medium,material ratio,reaction times and pH values.Therefore,the design and construction of CPs with high selectivity,high sensitivity and good recycling abilities are the key problems to be solved.In this thesis,seven novel CPs have been solvothermally synthesized based on the aromatic polycarboxylates:1,3,5-tris(4-carbonylphenyloxy)benzene(H3TCPB),3,5-(3',5'-triscarbonylphenyloxy)benzene(H5L),2'-amino-[1,1',4'',1'-3 phenyl]-3,3',5',5'-tetracarboxylic acid(H4PTA),the N-cotaining ligands of 1,3-di(pyridyl)propane(1,3-dpp),1,4-bis(imidazole-1-methyl)benzene(bimb),1,10-phenanthroline(Phen)and Zn(?)/Cd(?) metal ions with d10 configuration and lanthanide Tb(?) metal ions.Their structures were characterized by X-ray single-crystal diffraction,elemental analysis(EA),infrared spectroscopy(IR),and thermogravimetric(TG) analysis.In addition,the luminescence sensing experiments of the above-mentioned CPs and post-synthetic modified CPs to different analytes were carried out.The specific contents and results are as follows:(1)Structural analysis showed that Zn-CP 1 is a 2-fold interpenetrated three-dimensional(3D)framework.Cd-CP 2 presents a 3-fold interpenetrated 3D framework.Cd-CP 3 displays an unprecedented 3D framework.Tb-CP 4 shows a porous framework.Cd-CP 5 exhibits a 2D sheet with the porosity of 43.0%.And the amino-modified Cd-CP 6 reveals an interesting 3D porous network.While Zn-CP 7 manifests itself as an unprecedented 3D structure with the porosity of 63.3%.(2)Luminescence sensing experiments exhibited that Zn-CP 1 and Cd-CP 2 showed excellent performances for the detection of Fe3+ions and Cr2O72-anions in the presence of other interfering ions,and the limits of detection(LOD) can be as low as 7.18×10-6 M for Fe3+ions and 1.15×10-7 M for Cr2O72-anions,respectively.The excellent detection performance can mainly be attributed to the static quenching process and the F?rster resonance energy transfer(FRET)caused by the overlap between the emission spectra of CPs and the UV absorption spectra of the analytes.(3)Cd-CP 3 and Tb-CP 4 as chemosensors presented high selectivity,high sensitivity and good recycle abilities for the detection of NACs(nitrobenzene derivatives)and NFs(furan antibiotics)in aqueous solutions,respectively.With the help of UV absorption spectra analysis and density functional theory(DFT)calculation,the luminescence recognition mechanism can be ascribed to the synergistic effect of the photo-induced electron transfer(PET) between CPs and analytes,the F?rster resonance energy transfer(FRET) caused by the overlap between the emission spectra of CPs and the adsorption spectra of the analytes.In addition,there exists two kinds of one-dimensional(1D)channels in Tb-CP 4,that is the rectangular one(11.115?×13.231?)and the quadrilateral one(12.228?×19.210?),which can absorb(Nitrofuranone,NZF;Nitrofurantoin,NFT)and their adsorption amounts are 81.3%and 84.4%,respectively.(4)To further improve the luminescence detection performance of CPs,the dye molecules(RhB) were encapsulated into the cavities of Cd-CP 5 to fabricate RhB@Cd-CP 5 composites,which showed high selectivity,high sensitivity and good recycle abilities for the detection of parathion methyl and parathion,and the limit of detection(LOD) is 1.43×10-5 M and 3.9×10-5 M,respectively.The luminescence sensing mechanism can be mainly attributed to the photo-induced electron transfer(PET) between CPs and analytes,and the non-radiative energy conversion process-internal filtering effect(IFE).In addition,the residue(0.1 ppm) of parathion on the fresh pear surface can be observed under UV irradiation.(5)Cd-CP 6 has excellent detection ability for the pH=3-7 in water system.To realize the rapid recycling of Cd-CP 6,magnetic?-Fe2O3 anoparticles were successfully encapsulated into the cavities of Cd-CP 6 to fabricate the magnetic composite?-Fe2O3@Cd-CP 6.Compared with Cd-CP 6,?-Fe2O3@Cd-CP 6 can not only be recovered quickly with magnets but also showed the subtle corresponding error value of-0.06?-0.19 at the same conditions,indicated that?-Fe2O3@Cd-CP 6 can replace Cd-CP 6 as a pH sensor.The pH sensing mechanism of Cd-CP 6can mainly be attributed to that the amino(–NH2)in Cd-CP 6 can be protonated into ammonium(–NH3+)under acidic conditions,which further changed its charge transfer ability.(6)As an exploration of CPs as a sensor to detect biological small molecules,a bimetallic Ce@Zn-CP 7 composite was constructed through post-synthetic modification by the incorporation of the Ce(?) ions into the cavities of Zn-CP 7.Electrochemical behaviors of Zn-CP 7 and Ce@Zn-CP 7 based sensors for the detection of UA were investigated by using the cyclic voltammetry(CV) and differential pulse stripping voltammetry(DPV).The results showed that Ce@Zn-CP 7/GCE-based sensor displayed a low LOD of 0.3×10-7 M,which was attributed to the large specific surface area of Zn-CP 7,the synergistic effect between Zn(?) and Ce(?),and the change of response current caused by the change of chemical valence state of Ce(?) ion in the reaction process.In addition,Ce@Zn-CP 7/GCE-based sensor exhibited remarkable stability,excellent selectivity and good renewability for the sensing of UA. |
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