| Metal-organic frameworks(MOFs),a new emerging class of crystalline porous materials,are assembled from metal ions or clusters and organic ligands by means of coordination bonds,and through organic linkers to form one-dimensional(1D)chain,two-dimensional(2D)layer or three-dimensional(3D)supramolecular network periodicity structure.It has attracted increasing interests mainly because of their high degree of crystallinity and surface area,well-defined pore structure,and adjustable pore size.The advantages of their low density and tunable local environment,which facilitates mass diffusion,have led MOFs to diverse applications,including catalysis and biomimetics,magnetism,gas sorption and separation,luminescence,chemical sensing and others.Based on the above considerations,in order to further study the relationship between the synthesis,structure and properties of MOFs,this paper selects one imidazole ligand and three carboxylic acid ligands to react with transition metal salts through the solvent method.10 MOFs single crystal structures were obtained by self-assembly of imidazole and carboxylic acid mixed ligands and metal ions.The structure was determined by means of X-ray single crystal diffraction(XRD)experiment,and it was characterized by solid-state and crystal suspension fluorescence spectroscopy(FL),powder X-ray diffraction(PXRD),circular dichroism(CD),thermogravimetric analysis(TGA),ultraviolet spectroscopy(UV-vis)and other analytical methods,and partly studied the properties of its luminescence and fluorescence chemical sensing.The specific content of this paper is mainly divided into the following three parts:1.Using 1,3,5-triimidazolylbenzene(L)ligand and chiral camphor acid(D-H2cam)as mixed ligands.The mixed ligands respectively combined with the transition metal Cd(CH3COO)2·2H2O and Zn(CH3COO)2·2H2O to synthesize[(Cd2+)2(L)2(D-H2cam)2]·2H2O(1)and[(Zn2+)3(L)2(D-H2cam)3]·3H2O(2)two chiral transition MOFs materials via solvothermal method.The structure of the single crystal was determined by XRD.The crystal purity,chirality and thermal stability of the samples were analyzed by PXRD,CD,TGA and other characterization methods.In addition,the fluorescence and chemical sensing properties and mechanisms of single crystal samples were studied.2.Using L ligand respectively with 2,5-furandicarboxylic acid(FDCA)and 2,5-thiophene dicarboxylic acid(H2L1)as mixed ligands.The mixed ligands respectively combined with the transition metal Zn(CH3COO)2·2H2O,Mn(CH3COO)2·4H2O and Ni(CH3COO)2·4H2O to synthesize[(Zn2+)(L)2(H2O)2]·6(H2O)·2(FDCA)(3),[(Mn2+)(L)2(H2O)2]·6(H2O)·2(FDCA)(4),[(Ni2+)2(L)2(FDCA)2(H2O)4]·H2O(5),[(Ni2+)2(L)2(H2L1)2](6)four kinds of transition MOFs materials via solvothermal method.Their crystal structures were determined,and the crystal phase purity and thermal stability were analyzed.In addition,the fluorescence and chemical sensing properties and mechanism of Zn-MOF(3)were analyzed.3.Using L ligand and FDCA carboxylic acid ligand as mixed ligands.The mixed ligands respectively combined with the transition metal Co(CH3COO)2·4H2O,Cu(CH3COO)2·4H2O and Cu(NO3)2·3H2O to synthesize[(Co2+)(L)(FDCA)(H2O)2]·0.5(H2O)(7),[(Co2+)0.5(L)(H2O)]·3(H2O)·(FDCA)(8),[(Cu2+)(L)(FDCA)(H2O)]·2(H2O)(9),[(Cu2+)(L)2(H2O)2]·6(H2O)·2(FDCA)(10)four kinds of transition MOFs materials via solvothermal method.On the basis of their precise determined structure,further analyzed their crystal phase purity and thermal stability. |
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