镧系配位聚合物的合成、结构和发光性质研究

发布时间：2018-07-22 17:03

【摘要】：配位聚合物(coordination polymers,CPs)是由金属离子(或金属簇)通过适合长度的配位键与多齿有机配体桥连构筑而成,在一维,二维和三维空间中呈现出无限链状或网络状的结构,其又被称为金属有机骨架化合物(metal organic frameworks,MOFs)。在过去的二十年里,因为其合成路线简单以及X-射线晶体学技术的普遍应用,CPs的研究获得飞速发展,并被广泛地应用于气体储存与分离、催化、磁性、导电性、发光、传感、药物缓释等领域。在多种多样的CPs中,镧系金属配位聚合物(lanthanide coordination polymers,Ln-CPs)因其具有独特的光学性质(如高的发光效率、独特的狭窄发射峰、长的荧光寿命和在原色发光范围内完全跨越整个可见光谱的发射)尤其引人瞩目,在变光和白光材料的设计合成上极具前途。CPs主要通过自组装的方法,即结晶制备,因此,有机配体和溶剂的种类、反应物的浓度、体系的p H、反应温度和时间将直接影响CPs合成的结果,其中,具有合适的形状、功能性和对称性的有机配体在多孔CPs的合成中起关键作用。目前,具有优异的配位能力和多样的配位模式的双功能化的吡啶羧酸类有机配体及其衍生物已被广泛用于合成稳定的多孔CPs。在本论文中,我们选择含氮双羧酸类有机配体(4-羟基吡啶-2,6-二羧酸,4-hydroxypridine-2,6-dicarboxylic acid,H2L1和5-(4-吡啶)-间苯二甲酸,5-(4-pyridiyl)-isophthalic acid,H2L2)与镧系金属离子反应,在水热/溶剂热条件下合成出10个Ln-CPs,并对其进行结构分析、基本性质表征和发光、磁性、金属离子荧光响应等性能研究。1、以H2L1为有机配体,在水热条件下合成出5个Ln-CPs:[Ln2(L1)3(H2O)4]·2H2O(Ln=Eu(1),Tb(2),Gd(3))和[Gd2(H2O)4(L1)(C2O4)2]·3H2O(4)。值得注意的是,在化合物4中,参与配位的草酸根是由H2L1配体发生部分原位反应分解生成的。由于化合物1,2和3同构,通过改变起始镧系元素金属盐用量并优化Eu3+,Tb3+和Gd3+离子的摩尔比,合成一系列掺杂的Ln-CPs[(Eu0.02-xTbx Gd0.98)2(H2O)4(L1)3]·2H2O(x=0,0.002,0.005,0.008,0.010,0.012,0.015,0.018,0.020),其可实现从红光经过黄光到绿光的转变,并通过增加Gd3+的量,得到化合物[(Eu0.0073Tb0.0007Gd0.992)2(H2O)4(L1)3]·2H2O(5)。当激发波长为340 nm时,化合物5呈现了白光发射,CIE坐标为(0.336,0.327)非常接近于纯白光发射的CIE值(0.333,0.333)。此外,化合物3的磁性研究表明Gd3+离子之间存在弱铁磁相互作用。2、以H2L2为桥联配体在溶剂热条件下合成出5个化合物:[Ln(H2O)2(HL2)(L2)](Ln=Eu(6),Tb(7),Gd(8)),[Tb1-x Eux(H2O)2(HL2)(L2)](9),[Gd0.998Tb0.0012Eu0.0008(H2O)2(HL2)(L2)](10)。其中,化合物6-8为同构的2D层状化合物。Eu3+/Tb3+掺杂的Ln-CPs,[Tb1-xEux(H2O)2(HL2)(L2)](9)(x=0,0.033,0.067,0.133,0.2,0.4,0.5,0.6,0.8,1.0)可实现从绿光经过黄光到红光的转变,且荧光寿命结果可证明Tb→Eu的能量转变。化合物10显示出白光发射,其CIE坐标为(0.327,0.329)。此外,化合物6对水溶液中的金属离子Mn+(n=1-3)有荧光响应,在激发波长为320 nm时,碱金属Na+对化合物6无明显的淬灭现象,而Ni2+、Cu2+和Cr3+有明显的淬灭效果,且当Ni2+、Cr3+溶液的溶度为10-5mol.L-1时,也显示出很好的荧光响应。
[Abstract]:The coordination polymer (coordination polymers, CPs) is constructed from metal ions (or metal clusters) through a suitable length coordination bond with a multi tooth organic ligand bridge. In one-dimensional, two-dimensional and three-dimensional space, an infinite chain or network structure is presented. It is also known as the metal organic frameworks, MOFs. In the past twenty years, because of its simple synthesis route and the universal application of X- ray crystallography, the research of CPs has developed rapidly and has been widely used in the fields of gas storage and separation, catalysis, magnetism, conductivity, luminescence, sensing, drug release, and so on. In a variety of CPs, lanthanide coor Dination polymers, Ln-CPs) is especially attractive because of its unique optical properties (such as high luminous efficiency, unique narrow emission peak, long fluorescence lifetime, and completely across the whole visible spectrum within the range of primary color). In the design of light and white light materials, the promising method of self assembly is a promising method. That is, crystallization is prepared. Therefore, the types of organic ligands and solvents, the concentration of reactants, the P H of the system, the reaction temperature and time will directly affect the results of CPs synthesis, in which the organic ligands with proper shape, function and symmetry play a key role in the synthesis of porous CPs. The bifunctional pyridine carboxylic ligands and their derivatives have been widely used in the synthesis of stable porous CPs. in this paper. We choose a nitrogen containing bicarboxylic acid organic ligand (4- hydroxypyridine -2,6- two carboxylic acid, 4-hydroxypridine-2,6-dicarboxylic acid, H2L1 and 5- (4- pyridine) - benzoate two formic acid, 5- (4-pyridiyl) -isophthalic. Acid, H2L2) reacted with lanthanide metal ions and synthesized 10 Ln-CPs under hydrothermal / solvothermal conditions. Their structure analysis, characterization of basic properties, luminescence, magnetic properties and fluorescence response of metal ions were studied.1, with H2L1 as organic ligand, and 5 Ln-CPs:[Ln2 (L1) 3 (H2O) 4] 2H2O (Ln=Eu (1), Tb (2), 3) under hydrothermal conditions. And [Gd2 (H2O) 4 (L1) (C2O4) 2]. 3H2O (4). It is worth noting that in compound 4, the oxalic acid root involved in the coordination ligand is decomposed by partial in situ reaction of the H2L1 ligand. As the isomorphic of compound 1,2 and 3, a series of doped Ln-CPs is synthesized by changing the initial lanthanide element metal salt and optimizing the molar ratio of Eu3+, Tb3+ and Gd3+ ions. [(Eu0.02-xTbx Gd0.98) 2 (H2O) 4 (L1) 3]. 2H2O (x=0,0.002,0.005,0.008,0.010,0.012,0.015,0.018,0.020), which can realize the transformation from yellow to green light from red light, and obtain compounds [(Eu0.0073Tb0.0007Gd0.992) 2 (H2O) 4 (L1) 3]. 5) by increasing the amount of Gd3+. When the excitation wavelength is 340, the compound 5 presents white light emission. The coordinates are (0.336,0.327) very close to the CIE value (0.333,0.333) of pure white light emission. In addition, the magnetic study of compound 3 shows that there is a weak ferromagnetic interaction between Gd3+ ions,.2, and H2L2 as the bridge ligands under the solvent thermal condition to synthesize 5 compounds: [Ln (H2O) 2 (HL2) (L2)] (Ln=Eu (6), Tb (7), 2) (9)). D0.998Tb0.0012Eu0.0008 (H2O) 2 (HL2) (L2)] (10). Among them, compound 6-8 is an isomorphic 2D layered compound of.Eu3+/Tb3+ doped Ln-CPs, [Tb1-xEux (H2O) 2 (HL2) (L2)] (9) (x=0,0.033,0.067,0.133,0.2,0.4,0.5,0.6,0.8,1.0) can realize the transition from green light to red light, and the fluorescence lifetime results can prove the transformation of energy. The compound 10 shows a white light emission, and its CIE coordinates are (0.327,0.329). In addition, the compound 6 has a fluorescence response to the metal ion Mn+ (n=1-3) in the aqueous solution. At the excitation wavelength of 320 nm, the alkali metal Na+ has no obvious quenching phenomenon to the compound 6, while Ni2+, Cu2+ and Cr3+ have obvious quenching effects, and the solubility of Ni2+, Cr3+ solution is 10-5mol.L-1. It also shows a good fluorescence response.
【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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