Synthesis And Properties Of The Rare-earth (Cluster) Metal-Organic Framework

Metal-organic frameworks (MOFs) also called porous coordination polymers (PCPs) have emerged as a novel category of porous materials. Polynuclear lanthanide metal-organic frameworks (Ln-MOFs) as multifunctional materials exhibit many properties within their structure, and therefore they are promising applications for several research areas, such as gas storage, luminescence, catalysis, sensing, ion exchange and so on. More particularly, the polynuclear lanthanide metal-organic frameworks (Ln-MOFs) based on part 4f shell lanthanide ions have unique chemical and physical properties, as well as their unusual electronic structures, lead to rich applications especially in luminescence and sensing. However, the design and synthesis of the polynuclear rare earth clusters is a significant and challenging task. Recently, with the rapid development of polynuclear rare earth clusters of research, the study of rare earth clusters as building blocks synthesis of functional MOFs caused the attention of chemists and materials scientists. So the choice of the organic ligand and metal salt for the synthesis of functional MOFs are of great significance. In this paper we selected four organic ligands:p-terphenyl-4,4"-dicarboxylic acid,2’,5’-Dimethyl (H2L),2’-amino-1,1’:4’,1"-terphenyl-4,4"-dicarboxylic acid (H2tpd-NH2),4,4’-Stilbenedicarboxylic acid (H2SDA) and 4’-(1H-tetrazol-5-yl)-biphenyl-3,5-dicarboxylic acid (H3TZPI) with rare earth salt to form five porous lanthanide metal-organic frameworks. These polynuclear lanthanide metal-organic frameworks were characterized by X-ray single-crystal diffraction, IR spectra, elemental analysis, X-ray powder diffraction, thermogravimetric analysis, and we discussed their structural characteristics and fluorescence properties. This paper includes the following four chapters:We introduced the polynuclear rare earth metal-Organic Framework and the significance and the progress made in this paper.In the first chapter, we choice linear ligand and Ln(NO3)3·6H2O (Ln=Eu, Tb) synthesized four lanthanide-organic frameworks with the formulas [(CH3)2NH2]2[Ln6(μ3-OH)8(L)6]·(solv)x [Ln=Eu(1), Tb(2)], [(CH3)2NH2]2[Eu6(μ3-OH)8(tpd-NH2)6](solv)x(4) and [Eu6(μ·3-OH)8(SDA)6]·(solv) x(5), we discussed their structural characteristics and properties. Single-crystal X-ray diffraction analysis reveals that the structures of 1,2 and 4 are isostructural,1 is a MOF with the anticipated fcu topology constructed from the bridged hexanuclear clusters, the carboxylate carbon atoms of the coordinated ligands act as points of extension and correspond to the vertices of the quasiregular face-centered cubic (fcu) net,5 is a 2D network.3 have been successfully obtained by doping isostructural Eu3+ into Tb3+ compounds to tune the emission colors by adjusting the doped Eu3+ concentration, and we discussed 1、2、3 luminescence properties.In the second chapter, the solvothermal reaction of H3TZPI with Tb(NO3)3·6H2O lead to one componds {[Tb2(TZPI)2(DMF)4(H2O)4]·4H2O}n(6).6 is a 3D network dinuclear lanthanide metal-organic frameworks, and we discussed their structural characteristics and fluorescence properties.In the third chapter, we have summarized the structures of the five Metal-organic frameworks.