| As an important class of hybrid inorganic-organic materials, metal-organic frameworks (MOFs) have attracted more and more attention over the past decade because of their intriguing topological structures and applications in many areas (such as gas storage, separation, catalysis, and molecular recognition, etc).Metal-organic frameworks (MOFs), usually refer to a kind of crytalline materials with period structures constucted from rigid or half-rigid organic ligands and metal ions or metal clusters by coordination bonds through a self-assembly process.MOFs have crystal structures like zeolites, but usually bigger surface areas and porous structures. MOFs can be partly targeted synthesized due to their organic component part, meanwhile with unique multifunctional properties in optic, electric, and magnetic fields.Recently, many researchers have focused on utilizing ligands containing ethynyl group for preparation of MOFs with permanent porous compounds, because ethynyl group could expand the structures by elongated ligands.Researchers have accumulated a lot of experimence and knowledge about the rule to synthesize MOFs, and the design and synthesis of ligands containing ethynyl group has developed to an important part of crystal engineering. However, the design and synthesis of MOFs containing ethynyl group with unique properties are not enough.This thesis focuses on the porous properties of MOFs, we design and synthesize rigid carboxylic ligands containing ethynyl group, aim to synthesis of MOFs with unique porous properties and accomulate valuable experimental basis.The study mainly includes the following four aspects:(1) Lanthanide metal-organic frameworks are of interest in view of their special chemical and physical properties arising from 4f electrons of lanthanide ions, such as luminescence and magnetism. Although a number of lanthanide metal-organic frameworks with various dimensionalities and topologies have been prepared from multicarboxylate ligands, it is still a challenging task to rationally design and synthesize lanthanide MOFs because of their high and variable coordination number and flexible coordination environment. We design novel tricarboxylate ligand 5-((4-carboxyphenyl)ethynyl)isophthalic acid (H3CPEIP). There are two distinct carboxyl groups on the two different phenyl rings and an additional ethynyl group which can elongate the size of ligand. We have synthesized a family of novel 3D lanthanide metal-organic frameworks with rare (3,6)-connected topology, which are constructed from common six-connected binuclear [Ln2(COO)6] cluster and three-connected CPEIP ligand. Furthermore, the luminescent properties of compounds are studied.(2) A novel metal-organic framework [C102H14CU6O7] with agw topology, has been synthesized using organic ligand 5-((4-carboxyphenyl)ethynyl)isophthalic acid under solvothermal conditions. The compound consists of three types of cagelike structures, containing both the common binuclear Cu(II) cluster and the uncommon trinuclear Cu(II) cluster. The largest aperture is about 10.4A×18.7A. The BET surface is about 2313m2/g。(3) There are lots of usual topological nets, such as dia net, NbO net, primitive cubic network (pcu), bodycentered cubic network (bcu) etc. Especially the NbO net has attracted more and more attention because of the simple nodes and regularly structure. We have synthesized a novel organic ligands containing four COO- groups. A novel metal-organic framework with NbO topology, has been synthesized using this organic ligand. The compound has unique cage and sensitive to water molecule.(4) We also use organic template to synthesize an anionic MOF with Sodalite-type topology. It contains Cu4-(μ4-Cl)-BTC SBUs.
|
PDF Full Text Request