节点文献
三唑和四唑杂环配体配位聚合物的合成、结构及性能研究
Synthesis, Structures and Properties of Coordination Polymers Based on Triazole and Tetrazole Heterocyclic Ligands
【作者】 陈燕丽;
【作者基本信息】 吉林大学 , 无机化学, 2011, 博士
【摘要】 本论文是在水热和溶剂热条件下,以1,2,4-三唑(Htrz)和四唑乙酸(Htza)为配体进行了金属有机配位聚合物的合成、结构及性能研究。并对该体系金属有机配位聚合物的合成条件如:金属源、溶剂、温度、时间、pH值及添加剂等进行了系统考察。成功设计合成了一系列化合物,利用单晶x射线、粉末X射线、红外光谱、元素分析、热重分析和荧光光谱等手段对化合物进行了表征,为金属有机配位聚合物的合成积累了有价值的原始数据。在第二章中,以Htrz和刚性多羧酸(4,4’-联苯二甲酸,2’,4-联苯二甲酸,1,2,4-苯三甲酸和均苯四甲酸)为配体合成了六个金属有机配位聚合物。其中化合物1,3,4,5和6均为三维骨架结构,金属中心Zn(Ⅱ)通过三唑配体连接成不同的多核金属簇,这些簇进一步拓展成具有不同结构的一维棒状次级结构,该次级结构单元通过不同的刚性多羧酸配体连接成三维骨架结构。化合物2是二维层状结构。在化合物1和4中形成的[Zn4(μ4-O)(trz)2]4+和[Zn4(trz)3]5+簇在金属三唑体系中第一次被合成。化合物1是以[Zn4(μ4-O)(trz)2]为基元形成一个二重穿插的金刚石结构。化合物2是以[Zn2(trz)2]为基元形成一个6-连接的hxl拓扑结构。化合物3和4是(3,8)-双连接的tfZ-d拓扑结构,分别以[Zn5(trz)4]为基元和[Zn4(trz)3]为基元。化合物5是(4,12)-双连接的{(32.44)(38.424.524.610)}拓扑结构以[Zn7(trz)6]为基元。化合物6是(4,6)-双连接的{44.610.8}{44.6}拓扑结构。化合物1-6在室温下具有较强的荧光发射,可能成为潜在的荧光材料。在第三章中,以Htza为配体合成了两个铅的金属有机聚合物。化合物7是通过弱键形成三维超分子的骨架结构。化合物8是Pb(Ⅱ)和三桥联Cl-形成的二维无机层通过四唑乙酸连接成三维网络结构。在第四章中,以Htrz和Htza为添加剂,合成了两个铅的化合物。化合物9为三维无限网络结构,配体呈现三种配位模式。化合物10是3-连接二维骨架结构。同时还讨论了弱键对化合物7-10整体结构的影响。
【Abstract】 Coordination polymers are involved with the behavior of crystal engineering. Recently, the research of coordination polymers has attracted much attention because of their flexible tailoring, various topologies and their potential applications, such as gas adsorption, ion-exchange, molecular recognization, catalysts, magnetism, optics and so on. Up to now, according to the principle of crystal engineering, the design and synthesis of coordination polymers are invested a great deal of effort based on appropriate metal ions and versatile bridging organic ligands.In this paper, we report the preparations, crystal structures and properties of coordination polymers constructed from 1,2,4-triazole (Htrz) and tetrazole-1-acetic acid (Htza). Triazoles and tetrazoles are aromatic five-membered heterocycles containing three and four nitrogen atoms, respectively. Htrz as a multifunctional ligand, exhibits a strong bridged bonding ability for metal ions. The Htrz ligand through five different coordination modes can bridge metal ions. The protonated trz ligand may function as a dinucleating ligand (μ1,2 andμ2,4 binding modes), while deprotonated trz ligand can coordinate two or three metal ions (μ1,2,μ1,4 andμ1,2,4 binding modes). Its interesting bridging modes can afford polynuclear clusters as secondary building units (SBUs), such as dinuclear, linear trinuclear, tetranuclear, pentanuclear, hexanuclear, heptanuclear clusters and so on. Coordination polymers using Htrz ligand show various topologies and their potential applications. Compared to triazole, tetrazole holds an additional nitrogen atom and exhibits more bridging coordination possibilities. Tetrazole-1-acetic acid is bifunctional ligand containing of tetrazolate and carboxylate groups. Htza with four nitrogen atoms and two oxygens potential binding centers can serve as a class of excellent polydentate ligands. On the other hand, the -CH2- group between the tetrazole ring and carboxylate group offers flexible orientations of the carboxylate arm, which have been employed in construction of coordination polymers with structure varieties and novel performance. The Htza ligand is a suitable hydrogen bond donor and can form interesting supramolecular architectures throughπ-πinteractions. So we choose Htrz and Htza as organic ligands to design and synthesize a series of coordination polymers. In the second chapters, under hydrothermal or solvothermal conditions, six compounds were synthesized successfully with the aromatic carboxylate ligands in zinc-trz system, namely, Zn4(μ4-O)(trz)2(4,4’-bpdc)2 (1), Zn2(trz)2(2,4’-bpdc) (2), [Zn5(trz)4(btc)2(DMF)2(H2O)2]·2H2O·DMF (3), Zn4(trz)3(btc)2(CH3CN)(H2O)]·5H2O·(Bu4N) (4), [Zn7(trz)6(H2btec)2(btec)]·H2O (5) and [Zn3(trz)2(btec)(H2O)4]·2H2O (6), [4,4’-H2bpdc= 4,4’-biphenyldicarboxylate, 2,4’-H2bpdc= 2,4’-biphenyldicarboxylate, H3btc=1,2,4-benzenetricarboxylate, Bu4N= tetrabutylammonium, H4btec= benzenetetracarboxylate]. Compounds 1,3,4,5 and 6 also exhibt three-dimensional frameworks based on rod-link secondary building units (SBUs). Compound 2 is two-dimensional structures. All compounds also contain polynuclear zinc clusters. There are some distinct features in the structures of compounds 1 to 6. Compound 1 is a 2-fold interpenetrating diamond topology constructed from {[Zn4(μ4-O)(trz)24+]}n SBUs. Compound 2 is a two-dimensional 6-connected hxl network based on {[Zn2(trz)2]2+}n SBUs. Both compounds 3 and 4 exhibit three-dimensional (3,8)-connected tfz-d nets with{43}2{46.618.84} topology symbol built from rod-shaped {[Zn5(trz)4]6+}n SBUs (3) and {[Zn4(trz)3]5+}n SBUs (4). In 3 and 4 compounds, rod-like units are connected by btc ligands via different modes. Compound 5 is a three-dimensional (4,12)-connected network with (32.44)(38.424.524.610) topology symbol built from rod-shaped {[Zn7(trz)6]8+}n. Compound 6 shows a (4,6)-connected three-dimensional structure with Schlafli symbol {44.610.8}{44.62}, containing infinite straight {[Zn2(trz)2][ZnO4]}n chain with dinuclear [Zn2(trz)2] and [ZnO4] unit. The structure of compounds 3,4 and 6 are all high-connected nodes networks built from polynuclear metal clusters. The synthesis conditions of compounds 3 and 4 are also discussed, the experimental data show that the structures of 3 and 4 depend closely on the addition of Na2CO3 or tetrabutylammonium hydroxide. At the same time, the effect of action conditions were discussed between compounds 5 and 6, too.In the third chapter, we choose metal lead react with tetrazole-1-acetic acid and gain two coordination polymers Pb(tza)2 (7) and PbCl(tza) (8) under hydrothermal condition. We discussed the effect of alkali metal and alkali-earth metal on the synthesized compounds 7 and 8. Compound 7 is a three-dimensional supramolecular architecture. The coordination geometry of Pb(1) will transfer from hemidirected to holodirected geometry through the potential weak Pb-O and Pb-N bonds in 7. Compound 8 consists of two-dimensional inorganic layers by Pb(II) andμ3-Cl-, which are further linked by tza ligand to generate a novel a three-dimensional structure. There are three different rings [Pb2Cl2], [Pb2O2] and [Pb4Cl4] within the two-dimensional inorganic layers of 8. Compared to the structure of 7, we omitted Cl-atom in 8.Under hydrothermal conditions, the self-assembly of Pb(NO3)2,2,2’-oxydiacetic acid and Htrz (additive) generates a three-dimensional lead(Ⅱ) framework [Pb(oda)] (9). Compound 9 contains a one-dimensional infinite Pb-O chain which is connected throughμ3-,μ4-,μ5-coordination modes of oda to form a new three-dimensional structure. Compound [Pb(sui)] (10) was synthesized with succinic acid as organic ligand and Htza as additive. The structure of 10 containing one-dimensional rod-like linked adjacent [Pb2O2] units through together lead, which are connected by succinic acid ligand to form a 3-connected two-dimensional framework. For 9 and 10 when the bonding limit of Pb-O extends from 2.76 to 2.90 A and Pb-Pb extends 4.3 A, the potential weak bonds of Pb-O and Pb-Pb can be found, which construct a more complicated structure. The effect of additives (Htrz and Htza) was discussed between compounds 9 and 10.In conclusion, we report the preparations, crystal structures and properties of a series of coordination polymers constructed from aromatic five-membered heterocycles ligands (Htrz and Htza) in this paper. We also study the effect factors of the reactions and summarize the rules of synthesis. All the compounds charactrized by single-crystal X-ray diffraction analyses, X-ray power diffraction, elemental analyses, infrared absorption spectra and thermogravimetric analyses. Additionally, solid state fluorescent emission spectra of 1-6 compounds show fluorescent properties at room temperature.
【Key words】 Coordination polymers; Secondary building units; Crystal structure; Topology; Luminescence;