稀土离子与联吡啶羧酸构筑的金属有机骨架化合物的合成、结构与性能研究

发布时间：2018-02-09 12:20

本文关键词： 金属有机骨架化合物联吡啶羧酸配体镧系金属金属离子识别荧光调谐　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：金属有机骨架化合物(Metal Organic Frameworks,MOFs)作为近二十几年来的新型多孔材料受到了科学家们极大的关注。这类化合物是以金属离子或离子簇为中心,有机配体为延伸骨架,通过规则性排列构筑出具有特殊孔道的拓扑结构。而且在光,电,磁,吸附,气体储存,分离,催化等方面有着良好的性质以及重要的应用。镧系金属构筑的MOFs(Ln-MOFs)有着优异的光学性质,在荧光调谐,发光二极管,离子或分子检测,光转换光子器件,LED,彩色屏幕,荧光传感,生物传感等方面有着广泛的应用。这些应用与日趋热门的电子科技和生物技术进行交叉学科课题的研究有着重要的意义。镧系金属具有亲氧性,易与O原子进行配位,所以选用含有可以配位的O原子,例如含有羧酸基团的含N杂环类配体作为Ln-MOFs的配体,来提高镧系金属的发光强度,以此形成优异发光性质的金属有机骨架化合物。本文中选择合适的配体2,2’-联吡啶-5,5’-二羧酸(bpydc),通过溶剂热法利用镧系金属盐与制备了5个化合物[Ln_2(bpydc)_3(DMA)_2]·2DMA(Ln=Sm(1),Eu(2),Tb(3)),[Sm_2(bpydc)_3(DMF)_2(H_2O)]·2DMF(4),[Sm_2(bpydc)_3(DMA)_2(H_2O)_(0.5)]·1.5DMA(5)。其中化合物1-3为同构的不同镧系金属构筑的MOFs,具有不同的发光性能。化合物4是镧系金属的硝酸盐与配体构筑的具有三维菱形孔道MOFs,化合物5依赖第二配体的辅助得到较好的晶型,并获得单晶数据。这五个化合物中金属离子皆与O原子配位,不同的是,通过调控反应温度、压力、酸碱性以及其他条件的辅助等,来实现金属离子与配体分子或溶剂分子不同的配位模式,以此构筑出不同孔道结构的MOFs。并且通过X-射线粉末衍射,热重分析,红外光谱,荧光光谱的表征方法对这5个化合物进行了研究与分析。选择性质稳定且具有优异发光性质的化合物2(Eu)作为检测金属离子的探针,对8种金属离子Al~(3+),Fe~(3+),Li~+,Cd~(2+),Mg~(2+),Mn~(2+),Zn~(2+),Ca~(2+)(浸泡在为DMA中,金属离子浓度为10-3mol/L)进行定性检测。通过在紫外灯下的可视化观察得知:在含有0.01mol/LAl~(3+)的DMA溶液中,化合物2(Eu)失去原来的红光,而发出蓝色的光;在含有0.01mol/LFe~(3+)的DMA溶液中,化合物2(Eu)几乎不发光。通过荧光光谱图证实了这两个荧光现象。由于Ln-MOFs有着优异的光学性质,在5个已制备出的化合物选择性质稳定且发光性质良好的化合物进行荧光性质研究。根据化合物2(Eu),3(Tb)的不同发光性质,对金属中心进行修饰,掺杂不同比例的Eu~(3+)与Tb~(3+),制备得到4个具有相同结构不同金属中心的化合物6-9。随着Tb~(3+)/Eu~(3+)逐渐增加,化合物在紫外灯下的颜色逐渐从红光→绿光过渡,同时荧光光谱图中Eu的特征发射峰向Tb的特征发射峰过渡。同样通过测试这4个化合物的荧光寿命与量子产率说明它们的荧光性质变化规律。
[Abstract]:Metal Organic frameworks have attracted great attention of scientists as new porous materials in recent 20 years. These compounds focus on metal ions or clusters and organic ligands are extended skeletons. A topological structure with special pores is constructed by regular arrangement. And in light, electricity, magnetism, adsorption, gas storage, separation, The lanthanide metal MOFsLn-MOFs have excellent optical properties, such as fluorescence tuning, light-emitting diodes, ion or molecular detection, photonic devices, color screens, fluorescence sensing, etc. Biosensor has a wide range of applications. These applications are of great significance to the increasingly popular electronic and biological technologies for interdisciplinary research. Lanthanide metals are oxygenophilic and easy to coordinate with O atoms. Therefore, O atoms that can be coordinated, such as N heterocyclic ligands containing carboxylic groups, are selected as ligands of Ln-MOFs to improve the luminescence intensity of lanthanide metals. In this paper, we select the appropriate ligand 2m2hpyridine-5pyridyl-dipyridine-dicarboxylic acid bpydcr, and make use of lanthanide metal salts by solvothermal method to prepare five compounds [Ln_2(bpydc)_3(DMA)_2] 路2DMANU / Sm2Tb3CU, [Sm2bpydctctch2h2h2O3] 路2DMF4, [Sm2bpydccncnm2DMA2H2O0.5)] 路1.5DMA5. among them, compounds 1-3 are called "T _ 2H _ 2O _ 2H _ 2O _ (2)". MOFs constructed by different lanthanide metals have different luminescence properties. Compound 4 is a kind of lanthanide metal with three dimensional rhombic pore MOFs constructed by nitrate and ligand. Compound 5 depends on the assistance of the second ligand to obtain a better crystal form. The metal ions in these five compounds are all coordinated with O atoms, except by adjusting the reaction temperature, pressure, acidity and alkalinity, etc. To realize the different coordination modes of metal ions with ligand or solvent molecules, and to construct MOFs with different pore structures, and by means of X-ray powder diffraction, thermogravimetric analysis, infrared spectroscopy, The five compounds were studied and analyzed by means of fluorescence spectra. A stable and excellent luminescent compound 2o EU) was selected as a probe for the detection of metal ions. Eight metal ions (Al~(3) were qualitatively detected in DMA solution containing 0.01mol / L LAlO3). The compound 2EU lost its original red light in the solution of DMA containing 0.01mol / L Alnion 3 (immersed in DMA and the concentration of metal ion was 10-3mol / L). The blue light is emitted; in the solution of DMA containing 0.01mol / L Fefen 3), the compound 2o EU) is hardly luminous. The fluorescence spectra show that these two fluorescence phenomena are observed. Because of the excellent optical properties of Ln-MOFs, The fluorescence properties of five compounds with stable selective properties and good luminescence properties were studied. The metal centers were modified according to the different luminescent properties of compound 2OU (3) Tb. Four compounds with the same structure and different metal centers were prepared by doping different ratios of Eu~(3) and Tb~(3. With the increase of Tb~(3 / EEU ~ (3), the color of the compounds gradually changed from red light to red light. 鈫扐t the same time, the characteristic emission peak of EU in the fluorescence spectrum is transferred to the characteristic emission peak of TB. The fluorescence lifetime and quantum yield of the four compounds are also measured to show the variation of their fluorescence properties.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O641.4

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