Design, Synthesis And Structural Characterization Of Novel Polyoxometalates And Hybrid Complexes With Saturated And Monovacant Keggin Structures As Building Blocks

In this paper, it is focused on the design, synthesis and structural characterization of novel rare earth tungstogermanates and their organic hybridized complexes, which are based on monovacant Keggin polyanions [GeW₁₁O₃₉]^8-. Adopting (CH₃)₄NBr as counterion and exploring the synthetic method, a series of rare earth tungstogermanates RE/[GeW₁₁O₃₉](RE=Ce, Pr, Nd,Sm,Tb,Y,Yb) have been prepared, which include the lD zigzag and lD linear structures. Using RE2O3, HClO4 and α-KGeW11O39?nH2O as materials, we successfully crystallized four novel organic hybridized derivatives RE/[GeW₁₁O₃₉] (RE= Pr, Nd,Sm,Dy), these compounds exhibit lD double-parallel chainlike structure and lD chainlike structure. In addition, by rational experimental method, novel compounds assembled into polymers based on Keggin structural building blocks have been successfully isolated crystallized. Plenary Keggin anion [PW₁₂O₄₀]^3- together with DMSO molecules and alkaline cation Ba²⁺ in solution reacts to from the 1D double chainlike structural compound {[Ba(DMSO)₃(H₂O)₃][C₅H₆N]PW₁₂O(40)·DMSO·2H₂O}_n. Reaction between [SiW₁₂O₄₀]^4-, DMF and Ba²⁺ ions results in novel 2D network structural compound{[Ba₂(DMF)₅(H₂O)₅]SiW₁₂O₄₀·DMF·H₂O}_n. All the above compounds are characterized with elemental analysis, IR, UV spectra and X-ray crystallographic studies. In the solid state, all the compounds include infinite W-O-M-O-W chain. The metal centers M display their high coordination number and high oxophilicity ability, and they show many M-O bonds. For all the polyanions in this paper, from IR spectra, the PO₄, SiO₄, GeO₄ tetrahedrons and WO₆ octahedrons are all distorted to some extend, organic molecules DMSO or DMF are coordinated to the metal centers M through the oxygen atoms of the S=O or C=O bond. Such results are also conformed by X-ray crystallographic analysis. In the UV spectra, one absorption peak at a.v. 270 nm is the characteristic charge transfer between O_b,c→W of the [GeW₁₁O₃₉]^8- polyanion. The following are the crystal data of all compounds in this paper. 1. [Ba(DMSO)₃(H₂O)₃][C₅H₆N]PW₁₂O₄₀·DMSO·2H₂O: It belongs to triclinic space P-1, with unit cell dimensions a=12.285(3), b=22.717(5), c=12.186(5) A, α=101.05(3), β=115.98(3), γ=100.77(3)° , V = 2855.7(10) A³, F (000)= 3082, Z=2, μ=25.015 mm^-1. 2. [Ba₂(DMF)₅(H₂O)₅]SiW₁₂O₄₀·DMF·H₂O: It belongs to monoclinic space group P2₁/c, with unit cell dimensions a=12.957(3), b=21.232(4), c=23.387(5) A, β=93.74(3)° , V = 6420(2) A³, F (000)= 6536, Z=4, μ=22.733 mm^-1. 3. [(CH₃)₄N]_2.50H₍1.75([Ce_1.25(GeW₁₁O₃₉)(H₂O)_4.25]·1.5H₂O: It belongs to monoclinic space group, P2₁/n, with unit cell dimensions a=18.832(4), b=13.522(3), c=27.788(6) A, β=105.76(3)° , V = 6810(2) A³, F (000)= 5592, Z=4, μ=19.823 mm^-1. 4. [(CH₃)₄N]_2.25H_1.25[Pr_1.50(GeW₁₁O₃₉)(H₂O)₆.5]·0.5H2O: It belongs to monoclinic space group P2₁/n, with unit cell dimensions a=18.758(4), b=13.487(3), c=27.599(6) A, β=105.72(3)° , V = 6721(2) A³, F (000)= 5658, Z=4, μ=20.324 mm^-1. 5. [(CH₃)₄N]₂H_1.50[Nd1.50(GeW₁₁O₃₉)(H)2O))6]·3H)2O: It belongs to monoclinic space group P21/n, with unit cell dimensions a=18.846(4), b=13.443(3), c=27.561(6) A, β=105.75(3)° , V = 6720(2) A³, F (000)= 5702, Z=4, μ=20.401 mm^-1.6. [(CH3)4N]2H2.25[Sm1.25(GeW11O39)(H2O)4]·3.75H2O: It belongs to monoclinic space group P21/n, with unit cell dimensions a=18.781(4), b=13.388(3), c=27.534(6) A, β=105.73(3)° , V = 6667(2) A3, F (000)= 5605, Z=4, μ=20.497 mm-1. 7. [(CH3)4N]2H8[Tb(GeW11O39)(H2O)2]2·2.50H2O: It belongs to triclinic space group PÄ«, with unit cell dimensions a=18.247(4), b=19.294(4), c=23.081 A, α=107.09(3), β=109.50(3), γ=101.97(3)° , V = 6888(2) A3, F (000)=5210, Z=2, μ=19.793 mm-1. 8. [(CH3)4N]2.50H2.50[Y(GeW11O39)(H2O)2]·4H2O: It belongs to monoclinic space group, C2/c, with unit cell dimensions a=27.895(6), b=22.795(5), c=23.877(5) A, β=12...