| Metal-organic frameworks?MOFs?is a class of crystalline materials constructed by metal ions or metal clusters with organic ligands containing oxygen or nitrogen atoms,which possess unique physical and chemical properties such as large specific surface area,high porosity,good luminescence purity,long lifetime and high quantum yield.Currently,MOFs have been widely used in gas separation and storage,chemical sensing,magnetism,heterogeneous catalysis,bioimaging and drug delivery,etc.In this thesis,we chose 9H-carbazole-2,7-dicarboxylic acid as an organic ligand to coordinate with transition metal ions or rare earth metal ions,and successfully designed and synthesized three novel metal-organic complexes by the solvothermal method.The structures,phase purities and thermal stability of the complexes were characterized by single crystal X-ray diffraction,powder X-ray diffraction,1H NMR spectra,elemental analysis and thermogravimetric analysis.The fluorescence properties of complexes were analyzed and verified by infrared spectroscopy,ultraviolet absorption,fluorescence spectra.The effects of nitro compounds and metal ions on the fluorescence properties of the complexes were investigated.The main research results of this thesis include the following three aspects:1.A 3D metal-organic framework with the double interpenetrating structure?[Zn8L6??4-O?2?DMSO??H2O?3]?7DMSO??ZnL,DMSO=dimethyl sulfoxide?has been synthesized under the solvothermal condition and structurally characterized,which has a large unit cell volume?17736?3?.In ZnL,the structure contains two independent tetranuclear clusters,Zn4??4-O??COO?6?H2O?2 and Zn4??4-O??COO?6?DMSO??H2O?respectively.Two clusters are linked by the four oxygen atoms of the carboxylate groups to form the three-dimensional skeleton,and then the three-dimensional skeletons interpenetrate to form the double interpenetrating structure.Upon excitation at 396 nm,ZnL emits blue light and the emission maximum locate at 420 nm,which originated from the L2-ligand.2.A chain coordination polymer[CdL?H2O??DMF?2]·DMF?CdL,H2L=9H-carbazole-2,7-dicarboxylic acid,DMF=N,N-dimethylformamide?has been synthesized by the solvothermal condition and structurally characterized.Crystal structure reveals that each Cd2+ions are linked by four oxygen atoms of the carboxylate groups to form the 1D Cd-O-C chains along c axis.The cadmium complex contains a pair of enantiomers?CdL and CdL'?,and their 1D chains exhibit a mirror image relationship.CdL displays high structural stability in water with a pH in the range of3-10.Selective experiments with metal ions indicate that CdL exhibits clearly luminescent quenching response for selective detection of Fe3+in water with Ksv=8022 M-1 in the concentration range of 0-0.1 mM.In addition,CdL also displayed highly selective detection of PA in water with Ksv=17948M-1 in the concentration range of 0-0.05 mM.The above experimental results show that the complex CdL can act as a multi-response luminescence sensor material to detect Fe3+and PA in aqueous solution.3.A 3D metal-organic framework[Eu3L3?CH3COO?2?H2O?2??3-OH?]·3DMF?EuL,H2L=9H-carbazole-2,7-dicarboxylic acid?has been synthesized under solvothermal conditions and structurally characterized.In EuL,Eu6O8 clusters are four-bridged by carboxylates to form parallel-aligned Eu-O-C chains,which are further linked by the carbazole moieties of L2-ligands to form the three-dimensional framework with rhombic channels.The EuL material with characteristic emission of Eu3+ion exhibits significant luminescence quenching response for picric acid?PA?and the linear Stern-Volmer plot was observed in the concentration range of 0.05-0.15 mM with Ksv of 98074 M-1.As far as we know,this Ksv is among the highest values for COFs and MOFs in detection of PA.The excellent anti-interference ability and repeatability were also verified by experiments.Lastly,we investigated the luminescence quenching mechanism in the EuL sensing system. |
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