Syntheses And Luminescence Properties Of Lanthanide Metal Organic Frameworks Based On Triarylamine Carboxylic Acids

This thesis aims to synthesize Ln-MOFs with excellent optical properties as sensing platform.We employ the triarylamine tricarboxylic acids compounds containing a helical paddle structure as ligands,lanthanide metal ions as nodes to construct a series of 3D network Ln-MOFs by self-assembly.The structure,luminescence properties,fluorescence sensing detection as well as the diverse response mechanism for organic solvent molecules,nitro explosive molecules and metal ions of Ln-MOFs have been carefully explore.The specific contents are as follows:(1)Three triarylamine tricarboxylic acids ligands:6,6’,6’’-nitrilotri-2-naphthoic acid(H3NTN),tris(3 ’-carboxybiphenyl)amine(H3TCBA),tris(4’-carboxybiphenyl)amine(H3TCBPA),were prepared by improved methods.There were characterized by Elemental Analysis,Fourier-transform Infrared spectroscopy,Nuclear Magnetic Resonance and Electrochemical techniques.(2)Seven Ln-MOFs(1-7)were constructed by reacting lanthanide metal ions and above ligands.Structure and stability analysis shows that 1-7 exhibit non-interpenetrating 3D microporous structure containing 1D channels and the frameworks keep stable up to 400℃ in nitrogen atmosphere.(3)Fluorescence analysis shows that the ligands H3TCBA and H3TCBPA with suitable excited state energy levels effectively sensitize Tb(Ⅲ),which endows the compounds 3 and 6 strong bright green fluorescence emission.Meanwhile,a series of hetero-metallic Ln-MOFs:[TbxEu1-x(TCBA)(H20)2]2·DMF[x=0.028(8),0.111(9),0.322(10),0.394(11),0.682(12),0.737(13)and 0.816(14)]were obtained by the reaction of H3TCBA with blue-light emission and Tb(Ⅲ)/Eu(Ⅲ)with different doping ratios.Notably,the compound 14 shows a bright white light,which could be utilized as a promising white-light LED material.(4)Fluorescence sensing analysis shows that compound 3 can selectively detect NB among various of solvents.Due to the electron-withdrawing properties of nitro-explosive and matched size between the inherent 1D channels of 3 and nitro-explosive molecules,3 could be used as a high sensitivity luminescence sensor for the detection of TNP in ethanol with a detection limit of 1.64 ppb.Furthermore,compound 6 exhibits the capability of quick responsing and recogniting Fe3+ with a relatively low detection limit of 3.56 ppb in the presence of ten times interfering ions.And compound 6 can be used as a regenerable and recyclable sensor.