Polyoxometalates Or Organic Ligands Based Coordination Complexes: Synthesis And Catalytic Properties

(1) Synthesis and catalytic properties of coordination complexes based on polyoxometalatesThe crystalline solid-state polyoxometalates (POMs) can be constructed by crystal engineering approach based on functional polyoxometalate building blocks and connecting metal nodes. This kind of materials possesses definite frameworks structures and compositions, which can be fine-tuned to improve the catalytic activities of polyoxometalates. The well established relationship between the framework structures and catalytic activities can be used to instruct the design and modification of the catalytic actives of the as-synthesized materials.In this thesis, [M4(H2O)2(PW9O34)2]n- and [WM'﹛M(H2O)﹜2(ZnW9O34)2]n- were used as functional building blocks to construct POM solid frameworks linked by metal nodes or metal-organic ligands.18 compounds built from POM building blocks and metal connecting nodes were synthesized by suitable synthetic conditions, or ion exchange post-modification technique, which were subsequently characterized by single crystal X-Ray diffraction analysis, PXRD, IR and TGA. Furthermore, some of these compounds were used as catalysts to pompt the oxidative aromatization of dihydropyridines, homo-coupling reaction of arylboronic acids and oxidative cyclization of acetylacetone. The relationship between the catalytic activities and the framework structures was studied in details by comparison of the catalytic performances of these compounds.(2) Synthesis and catalytic properties of functional Metal-Organic FrameworksCatalytic properties of Metal-Organic Frameworks (MOFs) have received considerable attention because they can prompt various catalytic processes controlled by the porous size and shape, porosity and active sites. The synthesis of MOFs with specific catalytic activities for catalytic applications is an important research area.Three kinds of bridging ligands, pyridine-2,3,5,6-tetracarboxylic acid (H4pdtc), (E)-4-(2-(pyridin-4-yl)vinyl)benzoic acid (Hpyvba) and 2,5-bis(allyloxy)terephthalic acid (H2aotpa) were designed and synthesized for the construction of 13 novel coordination polymers, which were characterized by single crystal X-Ray diffraction analysis, PXRD, IR and TGA. The copper containing compounds were used as catalysts to prompt the Henry reaction, which demonstrated that microporous Metal-Organic Frameworks with accessible metal sites present high catalytic activity.