| Metal-organic frameworks ?MOFs? as a special class of solid state materials continue to attract remarkable attentions contributing to their structural diversity and tunable functionality. Due to the devisable characteristic of MOFs, their structural diversity could be realized by adopting structural modules, such as organic linkers and metal/metal cluster centers with various dimensions and shapes as building units. Introduction of the building units with different inherent functional moieties during the MOFs assembly or decoration of building units through post-synthetic modification are both ideal approaches to endow the MOFs potential applications.Considered to the intriguing structural characteristics and chemical properties of polynuclear rare-earth ?RE? clusters, MOFs constructed by RE clusters moieties have become a powerful candidate of the functional materials explored by scientists.In the first chapter, the development situation and study background of MOFs and the hot applications of functional MOFs in catalytic fields were introduced. In addition, the synthesis, properties and the application in the catalytic field of the multinuclear RE cluster-based MOFs have been also reviewed.In the second chapter, two series of rare-earth ?RE? MOFs incorporating trinuclear[RE3??3-OH??COO?6] SBUs and linear dicarboxylates, H2BDC ?1,4-benzenedicarboxylic acid? and H2NDC ?2,6-naphthalenedicarboxylic acid?, were synthesized with the formulas [?CH3?2NH2][RE3??3-OH??BDC?3?HCOO?3] ?RE = Y?1?, Er?2?, Tb?3?? and[?CH3?2NH2][RE3??3-OH??NDC?3?HCOO?3]?RE=Y?4?, Er?5?, Tb?6??, which feature three dimensional 12-connected frameworks with hcp topology. These materials show very high thermal and chemical stability in common organic solvents and water with pH values ranging from 2-12. Owing to the high-density of Lewis acidic sites, these complexes all exhibit high catalytic activity towards the cycloaddition of CO2 and epoxides under mild conditions.In the third chapter, two series of rare-earth ?RE? MOFs incorporating trigonal bipyramidal pentanuclear RE?III? clusters and pyridyl-supported tetracarboxylates?H4DDPY, 2,5-di?3,5-dicarboxylphenyl?pyridine? or pyridyl carboxylic acid-supported tetracarboxylates ?H4DDIA, 2,5-di?3,5-dicarboxylphenyl?isonicotinic acid? are presented.[RE5??3-OH?6?DDPY?2?H20?6]?NO3?·?solv?x?RE=Yb?7?,Er?8?, Dy?9??[RE5??3-OH?6?DDIA?2?H20?6]?NO3?·?solv?x?RE=Yb?10?, Er?11?,Dy?12??The pentanuclear RE?III? cluster shows uncommon trigonal bipyramidal geometry,which extended by tetracarboxylates to form a 3D porous framework with uniform M12Lg-cages constructed by 12 pentanuclear Yb?III? clusters and 8 tetracarboxylates with the size of ca. 20 AŚ17 A. Their highly CO2 uptake capacity and the existence of Lewis acidic sites make these MOFs promising catalysts for the chemical conversion of CO2.These MOFs demonstrate good catalytic activities and recyclability in the cycloaddition of CO2 and epoxides at 60? under 1 MPa CO2 pressure. In addition, the free -COOH groups in MOFs endow the materials with higher catalytic activity towards the ether bond-containing epoxides owing to the H-bonding interactions between the ether oxygen atoms of epoxides and the protons.In the fourth chapter, two new hexanuclear Y?III? cluster based MOFs have been successfully constructed by employing Y3+ and linear dicarboxylic linkers, H2bpdc?4,4'-biphenyldicarboxylic acid? and H2bpydc ?2,2'-bipyridyl-5,5'-dicarboxylic acid?.[?CH3?2NH2]2[Y6??3-OH?8?bpdc?6]·?solv?x?13, Y-bpdc?[?CH3?2NH2]2[Y6??3-OH?8?bpydc?6]·?solv?x ?Y-bpydc?The functional Pd?II? sites can be introduced in the framework by the metalation with Pd?II? of the functional pyridyl groups in bpydc ligand. In order to control the amount of Pd?II? sites, we constracted a series of MOFs possessing different ratio of bpdc and bpydc ligands via a ligand exchange strategy.[?CH3?2NH2]2[Y6??3-OH?8?bpdc?4.8?bpydc?1.2]·?solv?x?14?[?CH3?2NH2]2[Y6??3-OH?8?bpdc?3?bpydc?3]·?solv?x ?15?[?CH3?2NH2]1[Y6??3-OH?8?bpdc?1.2?bpydc?4.8]·?solv?x ?16?The modificative functional Pd??? sites make these MOFs materials a series of highly efficient and selective catalysts of the oxidative scission of olefins to aldehydes. The MOFs holding different amount of Pd??? sites show distinguishing catalytic activities toward this reaction.In the conclusion, the structural and catalytic studies of these multinuclear rare-earth cluster-based metal-organic frameworks have been summarized. The relation of the structural characteristic and the potential functionality has also been discussed. |
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