Functionalized Metal Oxide Clusters: Synthesis, Characterization, Crystal Structures, and Magnetic Properties of a Novel Series of Fully Reduced Heteropolyoxovanadium Cationic Clusters Decorated with

详细信息    查看全文

• 作者：M. Ishaque Khan ; Saadia Tabussum ; Robert J. Doedens ; Vladimir O. Golub ; and Charles J. O'Connor
• 刊名：Inorganic Chemistry
• 出版年：2004
• 出版时间：September 20, 2004
• 年：2004
• 卷：43
• 期：19
• 页码：5850 - 5859
• 全文大小：283K
• 年卷期：v.43,no.19(September 20, 2004)
• ISSN：1520-510X

文摘

A novel series of fully reduced heteropolyoxovanadium(IV) compounds, [MV^IV₆O₆{(OCH₂CH₂)₂N(CH₂CH₂OH)}₆]X(1, M = Li, X = Cl·LiCl; 2, M = Na, X = Cl·H₂O; 3, M = Mg, X = 2Br·H₂O; 4, M = Mn, X = 2Cl; 5, M = Fe,X = 2Cl; 6, M = Co, X = 2Cl·H₂O; 7, M = Ni, X = 2Cl·H₂O), have been synthesized and characterized by FT-IRand UV-vis spectroscopies, thermogravimetric analysis, elemental analysis, manganometric titration, temperature-dependent magnetic susceptibility measurements, bond valence sum calculations, X-ray powder diffraction, andsingle-crystal X-ray diffraction analyses. The structures of the crystals are comprised of discrete units of fullyreduced cluster cations, [MV^IV₆O₆{(OCH₂CH₂)₂N(CH₂CH₂OH)}₆]ⁿ⁺, counterions (chloride or bromide), and water ofcrystallization (in the case of 2, 3, 6, 7). In each case the cluster ion is composed of a fully reduced cyclic {MV₆N₆O₁₈}(M = Li, Na, Mg, Mn, Fe, Co, Ni) framework decorated with six triethanolamine ligands. Two arms of eachtriethanolamine ligand are coordinated to the metallacycle, and the third arm projects outward from the hexagonalring. The {MV₆N₆O₁₈} core adopts the Anderson-type structure. The cyclic core is comprised of a ring of sixedge-sharing {VO₅N} octahedra linked to a central {MO₆} unit. The hexametalate ring contains six d¹ ions {V^IV}and shows remarkable flexibility to encapsulate a variety of metal centers Mⁿ⁺ (Mⁿ⁺ = Li⁺, Na⁺, Mg²⁺, Mn²⁺, Fe²⁺,Co²⁺, Ni²⁺) with different (dⁿ) spins. The compounds show good thermal stability and exhibit interesting magneticproperties that make these magnetic clusters promising building blocks for constructing supramolecular structuresand extended structure magnetic solids. Crystal data for 1; C₃₆H₇₈Cl₂N₆Li₂O₂₄V₆, trigonal space group R, a =13.7185(3) Å, c = 24.8899(8) Å, Z = 3. Crystal data for 2: C₃₆H₈₀ClN₆NaO₂₅V₆, triclinic space group P, a =11.1817(5) Å, b = 12.1612(5) Å, c = 21.5979(10) Å, = 75.8210(10), ddle"> = 78.8270(10), = 71.1400(10), Z =2. Crystal data for 4: C₃₆H₇₈Cl₂N₆MnO₂₄V₆, monoclinic, space group P2₁, a =11.2208(5) Å, b = 21.5041(9) Å, c= 11.8126(5), ddle"> = 111.2680, Z= 2. Crystal data for 5: C₃₆H₇₈Cl₂N₆FeO₂₄V₆, monoclinic, space group P2₁, a =11.3057(7) Å, b = 21.4372(13) Å, c = 11.8167(7) Å, ddle"> = 111.4170, Z = 2.