The Study Of Three-Dimensional Inorganic-Organic Hybrids Based On Polyoxometalates

The aim of this thesis is to synthesize high-dimensional new inorganic-organic hybrid compounds by using sufficient-charge-density [H₂W₁₂O₄₀]6- cluster, two-electron reduced Keggin polyoxometalates, transition-metal substituted Keggin polyoxometalates and isopolymolybdate with transition metal and various organic bridging ligands, to study the synthetic conditions and rules for these compounds, to analysis the relationship between structures and properties and to explore the relationships between structures and nature of the materials.In this paper, twenty-eight new inorganic-organic hybrid compounds based on polyoxometalate building blocks have been synthesized under aqueous synthesis or hydrothermal technique, and structurally characterized by elemental analyses, IR, TG, XPRD, XPS and single crystal X-ray diffractions. The electrochemical properties, photoluminescence properties and catalysis properties of these compounds have been studied.1. Under aqueous synthesis condition, ten new derivatives based on [H₂W₁₂O₄₀]6- cluster with sufficient charge density have been synthesized and characterized: [Na2（H₂O）8Ag₂（HINA）3（INA）][Na（H₂O）₂Ag₂（HINA）4(H₂W₁₂O₄₀)]·2H₂O （1） [Ag5（INA）6（H₂O）₂][AlW₁₂O₄₀]·2H₂O （1a）[Ag₂（HINA）₂（INA）₎3（H₂O）5][SiW₁₂O₄₀]·H₂O （1b）[Na2（H₂O）4Ag6（HNA）₂（NA）₂(H₂W₁₂O₄₀)]·8H₂O （2） [H₂bipy]0.5[{Cu（bipy）₂}2{H₃W₁₂O₄₀}]·H₂O （3） [Co（bipy）3]3[{Co（bipy）₂（H₂O）}2{H₃W₁₂O₄₀}2]·H₂O （4） [CuI10（btp）10CuII（btp）₂][H₂W₁₂O₄₀]2·2H₂O （5） （H₃O）₂[CuII3（btb）6][H4W₁₂O₄₀]2·2H₂O （6） [CuI5（btpe）5][H₃W₁₂O₄₀] （7） [CuI5（btx）4][H₃W₁₂O₄₀] （8） HINA = pyridine-4-carboxylate HNA = pyridine-3-carboxylate bipy = 2,2’-bipyridine btp = 1,3-bis（1,2,4-triazol-1-yl）propane btb = 1,4-bis（1,2,4-triazol-1-yl）butane btpe = 1,5-bis（1,2,4-triazol-1-yl）pentane btx = 1,6-bis（1,2,4-triazol-1-yl）hexaneWhen Ag+ ions and HINA ligand are adopted, compounds 1, 1a and 1b have been synthesized under similar aqueous conditions by using （NH₄）₆[H₂W₁₂O₄₀]·3H₂O, K5[AlW₁₂O₄₀]·15H₂O and H4[SiW₁₂O₄₀]·14H₂O as building blocks, respectively. As the decrease of the charge density on the surface of Keggin POMs, the dimensionality of compounds 1, 1a and 1b degrade from 3D to 1D, gradually. It is the charge density on the surface of Keggin POMs that plays an important role in compound synthesis. That is to say, the more charge density on the surface of POMs, the easier to form high-dimensional hybrids. Compounds 1 and 2 are about the influence of isomeric ligands on the system of [H₂W₁₂O₄₀]6- cluster. 1 exhibits an unusual 1D-in-2D pseudo-polyrotaxane entangled structure, and 2 exhibits a 3D structure, in which each [H₂W₁₂O₄₀]6- cluster is connected with ten Ag atoms. Compounds 3?8 are about the influence of rigid or flexible ligands on the system of [H₂W₁₂O₄₀]6- cluster. Compounds 3 and 4 are discrete supramolecular structures, due to the 2,2’-bipy ligands adopt the coordination modes of nomal bidentate chelate with one metal ion, which terminates the dimensional extension. While all of compounds 5?8 show 3D structure, because the flexibility and conformational freedom of flexible ligands can conform to the coordination environments of transition-metal ions and/or POMs, which favors the formation of extended structures.2. Under hydrothermal synthesis condition, seven new 3D polyoxometalate-based derivatives based on reduced or transition-metal substituted Keggin with sufficient charge density have been synthesized and characterized, when Cu/Ag-btp ligand complexes were used: [CuI10（btp）10CuII（btp）₂][CoW₁₂O₄₀]2·2H₂O （9）[Ag6（btp）₄][CoW₁₂O₄₀] （10）[Ag5（btp）₄][PWVI10WV2O40] （11）[Ag5（btp）₄][PMoVI10MoV2O40] （12）[Ag5（btp）₄（H₂O）₂][PCuW₁₁O₃₉]·2H₂O （13）[Ag5（btp）₄（H₂O）₂][PMnMo₁₁O₃₉]·H₂O （14）[CuI4（btp）₄Na（H₂O）₂][PMnMo₁₁O₃₉]·2H₂O （15）Compounds 9 and 10 represent 3D framework based on [CoW₁₂O₄₀]6- building block linked by Cu/Ag-btp complexes. Compounds 11 and 12 show 3D isostructural framework based on [PWVI10WV2O40]5- and [PMoVI10MoV2O40]5- building block linked by Ag-btp complexes. Compounds 13?15 were obtained based on transition-metal substituted Keggin polyoxometalates. In compounds 13?15, transition-metal substituted Keggin polyoxometalates fuse at two oxo-groups to generate a polyoxometalates subchain. These subchains join by similar metal-organic complexes forming three 3D isostructural frameworks. The successful synthesis of compounds 13?15 change the actuality that compounds based on transition-metal substituted Keggin polyoxometalates are all low-dimensional.3. Under hydrothermal synthesis condition, eleven new 3D isopolymolybdate-based derivatives have been synthesized and characterized through tunning the length of flexible ligands and controlling the valence of metal ions by Et3N: [CuI2bte][a-Mo3O10] （16）[CuII（bte）1.5（H₂O）][γ-Mo8O26]0.5 （17）[CuI2btp][b-Mo3O10]·H₂O （18）[CuII（btp）₂（H₂O）][β-Mo8O26]0.5·2H₂O （19）[CuI2btb][β-Mo8O26]0.5 （20）[CuII2（btb）4][β-Mo8O26] （21）[CuI2btpe][β-Mo8O26]0.5 （22）[CuII（btpe）₂][β-Mo8O26]0.5 （23）[CuI4（btx）4][β-Mo8O26] （24）[CuI4（btx）₂][β-Mo8O26]·H₂O （25）[CuII2（btx）4][α-Mo8O26] （26）bte = 1,2-bis（1,2,4-triazol-1-yl）ethane Compounds 16?26 with 3D structure have been synthesized and characterized through tuning bte, btp, btb, btpe and btx ligands with different spacers （–（CH₂）n–, n = 2-6）, controlling the oxidation states of the Cu atoms by reducer Et3N. When the metal ions were Cu+ ions, the metal-organic complexes displayed 1D chains or 2D layers, while the metal ions were Cu²⁺ ions, the metal-organic complexes displayed 2D layers or 3D frameworks, the flexible [MoO₄]^2- ions acted as chameleon play to the score in forming right isopolymolybdates in order to conform to the coordination environments of metal-organic complexes. These isopolymolybdates link different metal-organic complexes all forming 3D structure. 19 displays a 3D polycatenated framework. In 21, the metal-organic complex contains both common- and meso-helix. 23 possesses a novel （2Dâ†'3D） interdigitated structure. In 26, the metal-organic complex shows a 3D self-penetrating hybrid network. In this work, the combination of the flexible uncertain in situ synthesization and crystal engineering featured design ideas and controlling synthesis, opens up new possibilities in pursuit of multifunctional materials.Additionally, we have studied the photoluminescent properties of POM-based inorganic-organic hybrid compounds modified by d0 metal ions and flexible bis（triazole） ligands, electrochemical properties of compounds 3 and 4, and photocatalysis properties of compounds 11 and 13.