The Studies Of Multinuclear Clusters Based On The Vacant Heteropolytungstates

The synthesis and properties of the high-nuclear polyoxometalates (POMs) is currently a major focus of research in recent years, which builds a bridge for the interdisciplinary research of POMs to the "synthetic biology" fields. The structural size of the high-nuclear POMs is up to the nano-scale, which makes it to be the important carriers of the solid inorganic chemistry, nano-materials chemistry and biochemistry research fields. In this paper, we synthesized a serials of multinuclear clusters based on the vacant heteropolytungstates, the lanthanide cations and transitional ions as linkers, using the molecular design ideas, the "one-pot" and "step-by-step" synthesis strategies. The properties, suitable synthetic methods, the factors and rules in the synthesis processes for these new compounds have been studied.Thirteen new multinuclear clusters based on the vacant heteropolytungstates have been synthesized employing the conventional solution synthesis and ionothermal synthesis methods, and also structurally characterized by elemental analyses, IR, UV-Vis, TG-DTA, XRD, diffuse reflectance UV-vis spectra, EPR, XPS and single crystal X-ray diffractions. The thermal stabilities and the stabilities in solutions, magnetic properties, electrochemical and electrocatalytic activities, luminescence properties and electrochemical activities of these compounds have been investigated.1. Three multinuclear polytungstoarsenate aggregates based on B-a-[AsW9O33]9- and Cerium cations have been synthesized with the step-by-step synthesis strategy. Compound 1 is a new dimeric sandwich-type compound obtained in the acidic aqueous solution of Na9[AsW9O33], ceric sulfate and potassium citrate at pH=3. The presence of citrate anion prevents the precipitation of Cerium cations with POMs. The reaction of compound 1 with a-alanine at pH=2 resulted in the formation of a new alanine-decorated cryptand compound 2. The reaction between compound 1 and MnCl2 at pH=5 yielded the other dimeric inorganic cryptate compound 3. Electrochemical analyses of compounds 1-3 suggest that tetravalent cerium ion can be stabilized by the polyanions with high negative charges. K9Na7[{Ce2O(H2O)5}{WO(H2O)}{AsW9O33}2]2·-48H2O (1) K2Na10[Ce4As4W44O151(ala)4(OH)2(H2O)10]·-40H2O (2) Mn0.5K5Na18[Ce4As4W41O49]·-50H2O (3)2. Employing "one-pot" synthesis strategy, compound 4 has been synthesized, which is a new POM-based 3d-4f heterometallic aggregate consisting of three{α-AsW10O38} fragments bridged by three{Fe-(μ3-O)3-Ce} heterometallic clusters. Its synthesis will provide a new model for the design and synthesis of magnetic POMs-based clusters. (4)3. Three multinuclear extended frameworks based on the sandwiching type POMs have been synthesized with the assistant synthesis using the Oxygen and Nitrogen-containing organic ligands to control the reaction activities. Compound 5 consists of a novel chiral ladder-like chain based on sandwich-type polyanions and lanthanide cations, which are further connected into a three-dimensional open framework by the potassium cations. In compound 6, each sandwiching polyoxoanion [{MnⅡ(H20)}2.5{(WO)(H2O)}0.5(AsW9O33)2]11- acts as a quadridentate ligand to connect with four neighbors via the mode of{W-O-Mn}, finally leading to an interesting 2D network. In compound 7, the polyoxoanions [Ce(AsW11O39)2]11-coordinate with the {KO5(H2O)[HMTA-CH3]} and{KO4(H2O)2[HMTA]} units to construct a new extended structure. K4Na2[{Ce(H2O)7}2Mn4Si2W18O68(H2O)2]·21.5H2O (5) {K3Na8[{MnⅡ(H2O)}2.5{(WO)(H20)}0.5(AsW9O33)2]·12.5H20}n (6) [HMTA-CH3]2[HMTA]K2Na7[Ce(AsW11O39)2]·19H2O (7)4. Three multinuclear clusters with various valences based on inorganic POM ligands have been synthesized with the assistant synthesis of the Oxygen and Nitrogen-containing organic ligands. Compound 8 is the first polytungstatoarsenate-based mixed-valent {FeⅢ12FeⅡ} aggregate and the largest iron cluster based on [AsW9O34]9- ligands. Compound 9 is a new Lindqvist-type polyoxoanion bisupported by copper(I) coordination cations and the 2,2'-bipy ligands, and exhibits a 3-D supermolecular framework by the aromaticπ-πstacking interactions. Compound 10 is a high-valent manganese(III)-substituted sandwich-type polyoxoanion with the assistant synthesis of isonicotinic. K8Na14[HMTA]4[(FeⅢ3FeⅡ0.25(OH)3)(AsO4)(AsW9O34)]4·24H2O (8) (4,4'-bipy)[Cu[(2,2'-bipy)2]2[W6O19] (9) (C6H5NO2)4{MnⅢ(H2O)}[AsⅢW9O33]2{W(OH)}{W(H2O)}·18H2O (10)5. Employing the ionothermal synthesis approach, three new transition-metal-containing multinuclear polyoxotungstate hybrids have been synthesized in 1-ethyl-3-methyl imidazolium bromide ([Emim]Br) ionic liquids (ILs). Compound 11 possesses a 3-D open framework constructed from the mono-ironⅢ-substitutedα-Keggin-type anion and the organic cations [Dmim]+through the hydrogen bond interactions. Compound 12 contains a [{FeⅢ3(μ2-OH)2(μ3-O)}3(μ4-WO4)] cluster surrounded by three [SiW9O34]10-ligands. The polyoxoanion of 13 consists of a high-valent trinuclear-manganese (Ⅲ)-substituted sandwiching polyoxoanion based on the [α-AsW9033]9-units. Compounds 11-13 exhibit good photocatalytic and electrocatalytic activities. [Dmim]2Na3[SiW11O39Fe(H2O)]·H2O (11) (Dmim=1,3-Dimethylimidazole) [Emim]9Na8[(SiW9O34)3{Fe3(μ2-OH)2(μ3-O)}3(WO4)]·0.5H2O (12) (Emim=1-Ethyl-3-methyl-imidazole) [Dmim]2[HMim]Na6[(AsW9O33)2{MnⅢ(H2O)}3]·3H2O (13) (Dmim=1,3-Dimethylimidazole; Mim=l-Methylimidazole)...