V16Sb4O42(H2O){VO(C6H14N2)2}4]: a terminal expansion to a polyoxovanadate archetype

The charge-neutral antimonatopolyoxovanadium(IV) cluster [V(IV)16Sb(III)4O42(H2O){V(IV)O(C6H14N2)2}4].10H2O.C6H14N2 was obtained under solvothermal conditions. The central cluster fragment, [V(IV) 16Sb(III)4O42], is a derivative of the [V18O42] archetype and is formed by replacing two VO5 polyhedra by two Sb2O5 units. The {V20Sb4} structure expands the {V16Sb4} motif by the addition of four square-pyramidal, terminal VO(1,2-diaminocyclohexane)2 groups. At low temperatures, the magnetic ground state is characterized by four independent S = 1/2 sites.     

Evolution of the structural chemistry of vanadium organodiphosphonate networks and frameworks: structural consequences of fluoride incorporation in the development of stable phases with void channels

Hydrothermal reactions of solutions containing a vanadate source, an organodiphosphonate, an organonitrogen component, and HF (V/P/O/F) yield a series of oxyfluorovanadium-diphosphonates with charge-compensation provided by organoammonium cations or hydronium cations. While V/P/O/F networks provide the recurrent structural motif, the linkage between the layers and the details of the polyhedral connectivities within the layers are quite distinct for the five structures of this study. [H2pip][V4F4O2(H2O)2{O3P(CH2)3PO3}2] (1) (pip = piperazine) is a conventional three-dimensional (3D) "pillared" layer structure, whose V/P/O/F networks are buttressed by the propylene chains of the diphosphonate ligands. In contrast, [H2en][V2O2F2(H2O)2{O3P(CH2)4PO3}] (2) and [H2en]2[V6F12(H2O)2{O3P(CH2)5PO3}2 {HO3P(CH2)5PO3H}] (3) are two-dimensional (2D) slablike structures constructed of pairs of V/P/O/F networks sandwiching the pillaring organic tethers of the diphosphonate ligands. Despite the common overall topology, the layer substructures are quite different: isolated {VO5F} octahedra in 2 and chains of corner-sharing {VO(3)F(3)} octahedra in 3. The 3D structure of [H2en]2[V7O6F4(H2O)2{O3P(CH2)2PO3}4].7H2O (4.7H2O) exhibits a layer substructure that contains the ethylene bridges of the diphosphonate ligands and are linked through corner-sharing octahedral {VO6} sites. The connectivity requirements provide large channels that enclose readily removed water of crystallization. The structure of [H3O][V3F2(H2O)2{O3P(CH2)2PO3}2].3.5H2O (5.3.5H2O) is also 3D. Because of the similiarity with 4.7H2O, it exhibits V/P/O/F layers that include the organic tethers of the diphosphonates and are linked through corner-sharing {VO6} octahedra. In contrast to the network substructure of 4.7H2O, which contains binuclear and trinuclear vanadium clusters, the layers of 5.3.5 H2O are constructed from chains of corner-sharing {VO4F2} octahedra. Thermal studies of the open framework materials 4 and 5 reveal that incorporation of fluoride into the inorganic substructures provides robust scaffoldings that retain their crystallinity to 450 degrees C and above. In the case of 4, dehydration does not change the powder X-ray diffraction pattern of the material, which remains substantially unchanged to 450 degrees C. In the case of 5, there are two dehydration steps, that is, the higher temperature process associated with loss of coordinated water. This second dehydration results in structural changes as monitored by powder X-ray diffraction, but this new phase is retained to ca. 450 degrees C. The materials of this study exhibit a range of reduced oxidation states: 1 is mixed valence V(IV)/V(III) while 2 and 4.7H(2)O are exclusively V(IV) and 3 and 5.3.5H2O are exclusively V(III). These oxidation states are reflected in the magnetic properties of the materials. The paramagnetism of 1 arises from the presence of V(III) and V(IV) sites and conforms to the Curie-Weiss law with C = 2.38 em K/(Oe mol) and = -66 K with mu(eff) (300 K) = 4.33 mu(B). Compounds 3-5 exhibit Curie-Weiss law dependence of magnetism on temperature with mu(eff) (300 K) = 5.45 mu(B) for 3 (six V(III) sites), mu(eff) = 4.60 mu(B) for 4 (seven V(IV) sites) and mu(eff) = 4.13 mu(B) for 5 (two V(III) sites). Compound 2 exhibits antiferromagnetic interactions, and the magnetism may be described in terms of the Heisenberg linear antiferromagnetic chain model for V(IV). The effective magnetic moment at 300 K is 2.77 mu(B) (two V(IV) sites).     

A novel series of vanadium-sulfite polyoxometalates: synthesis, structural, and physical studies

Reaction of NH4VO3 with sulfur dioxide affords the hexanuclear cluster (NH4)2(Et4N)[(V(IV)O)6(mu4-O)2(mu3-OH)2(mu3-SO3)4(H2O)2]Cl x H2O (1), and the decapentanuclear host-guest compound (Et4N)5{Cl subset [(VO)15(mu3-O)18(mu-O)3]} x 3 H2O (2). Sequential addition of magnesium oxide to an acidic aqueous solution of NH4VO3 (pH approximately 0) followed by (NH4)2SO3 resulted in the formation of either the non-oxo polymeric vanadium(IV) compound trans-(NH4)2[V(IV)(OH)2(mu-SO3)2] (3) or the polymeric oxovanadium(IV) sulfite (NH4)[V(IV)O(SO3)1.5(H2O)] x 2.5 H2O (4) at pH values of 6 and 4, respectively. The decameric vanadium(V) compound {Na4(mu-H2O)8(H2O)6}[Mg(H2O)6][V(V)10(O)8(mu6-O)2(mu3-O)14] x 3 H2O (5) was synthesised by treating an acidic aqueous solution of NH4VO3 with MgO and addition of NaOH to pH approximately 6. All the compounds were characterised by single-crystal X-ray structure analysis. The crystal structure of compound 1 revealed an unprecedented structural motif of a cubane unit [M4(mu4-O)2(mu3-OH)2] connected to two other metal atoms. Compound 3 comprises a rare example of a non-oxo vanadium(IV) species isolated from aqueous solution and in the presence of the reducing agent SO3(2-), while compound 4 represents a rare example of an open-framework species isolated at room temperature (20 degrees C). In addition to the synthesis and crystallographic studies, we report the IR and magnetic properties (for 1, 2 and 3) of these vanadium clusters as well as theoretical studies on compound 3.     

{(Mo)Mo5O21(H2O)3(SO4)}12(VO)30(H2O)20]36-: a molecular quantum spin icosidodecahedron

Self-assembly of aqueous solutions of molybdate and vanadate under reducing, mildly acidic conditions results in a polyoxomolybdate-based {Mo72V30} cluster compound Na8K16(VO)(H2O)5[K10 subset{(Mo)Mo5O21(H2O)3(SO4)}12(VO)30(H2O)20].150H2O, 1, a quantum spin-based Keplerate structure.     

{Mo102}型纳米多孔无机富勒烯衍生物的合成、表征及三阶非线性光学性质

在室温酸性条件下, 利用高负电性的表面分布有20个{Mo9O9}型纳米孔道的无机富勒烯囊状阴离子[{(MoⅥ)Mo5ⅥO21(H2O)6}12{Mo2ⅤO4(SO4)}30]72-与胍基乙酸反应, 得到了表面分布有20个{Mo6O6}型纳米孔道的由102个Mo及氧原子组成的[{(Mo)Mo5O21(H2O)4SO4}12{MoⅤO(H2O)}30]12-小无机富勒烯囊状阴离子. 通过单晶X射线衍射、元素分析、FTIR、UV-Vis、TG-DTA、ESR等手段对其进行了表征. 该化合物属于三斜晶系, P1空间群, 晶胞参数a=2.5377(5) nm, b=2.5932(5) nm, c=3.9547(8) nm, α =83.58(3) °, β=86.15(3) °, γ=75.55(3) °, V=25.023(9) nm3. 利用脉冲时间为5 ns的532 nm激光通过Z-扫描实验得到该化合物的三阶非线性折射率γ=-3.29×10-18 m2/W, 三阶非线性极化率χ(3)=-1.04×10-23 m2·V-2, 表明该化合物具有较强的自散焦三阶非线性光学效应.     

Synthesis and characterization of a polyoxovanadate cluster representing a new topology

A new type of mixed-valence polyoxoanionic cluster, [V(V)13V(IV)3O42(Cl)]8-, composed of 14 {VO5} square pyramids and 2 {VO4} tetrahedral units, hosting a chloride ion has been synthesized and characterized.     

Self-assembly of Yttrium-containing lacunary polyoxotungstate macroanions in solution with controllable supramolecular structure size by pH or solvent content

The self-assembly and the formation of "Blackberry" type supramolecular structures for a type of Yttrium-containing polyoxometalate (K 15Na 6(H 3O) 9[(PY 2W 10O 38) 4(W 3O 14)].9H 2O, or {P 4Y 8W 43}) macroanions is characterized by using static and dynamic light scattering techniques. {P 4Y 8W 43} macroions are found to form hollow, spherical, single-layer "blackberry" structures in water and water-acetone mixed solvents. Very interestingly, the blackberry size can be accurately controlled by either changing acetone content in water-acetone mixed solvents, or by changing solution pH in aqueous solution. The blackberry size increases with decreasing pH (lower charge density) or higher acetone content in the mixed solvent (lower dielectric constant) and the blackberry size can change in responding to the change of external conditions. This indicates that the {P 4Y 8W 43} macroanions possess the properties of both "strong electrolyte type" and "weak electrolyte type" macroions, as we outlined previously. This is due to the special chemical feature of such clusters, which can be treated as Na 2HPO 4-type electrolytes in solution. The kinetics of the blackberry formation can be controlled by temperature.     

Exploring the structure and properties of transition metal templated {VM17(VO4)2} Dawson-like capsules

Vanadate(V)-templated Dawson-type capsules {V(IV)M(VI)(17)(VO(4))(2)} (M = Mo, W; 1-2) have been synthesized and investigated by electrochemical methods in aqueous and organic media using spectroscopic techniques, EPR, UV-vis/NIR, IR, and CSI-MS (cryospray ionization mass spec.), and the clusters have been examined in the solid state by magnetic studies. The collision-induced dissociation (CID-MS) studies confirmed the solution structures as well as helped pinpoint the position of the vanadium ion on the {VM(17)}-type shell, which was corroborated by EPR and theoretical studies.     

Structural Variability of the Vanadium-Organodiphosphonate System: Hydrothermal Syntheses and Structural Characterizations of One-Dimensional, Two-Dimensional, and Three-Dimensional Phases

The hydrothermal chemistry of the CsVO(3)/methylenediphosphonate system was investigated. Variations in reaction temperatures, heating times, and stoichiometries of reactants resulted in the isolation of mononuclear, one-, two-, and three-dimensional species: Cs[VO(HO(3)PCH(2)PO(3)H)(2)(H(2)O)] (1), Cs[VO(HO(3)PCH(2)PO(3))] (2), Cs[(VO)(2)V (O(3)PCH(2)PO(3))(2)(H(2)O)(2)] (3), and [V(HO(3)PCH(2)PO(3))(H(2)O)] (4), respectively. The structure of the anion of 1 consists of isolated V(IV) octahedra. Phase 2 adopts a chain structure constructed from corner-sharing V(IV) octahedra, forming infinite {-V=OV=O-} linkages. The layer structure of 3 contains trinuclear units of corner-sharing {VO(6)} octahedra with the central V site in the III oxidation state and V(IV) centers at the extremities of the cluster. The diphosphonate ligands serve to link neighboring trinuclear motifs into a layer structure three octahedra in depth. The Cs(+) cations occupy cavities within the layers, rather than the more common interlamellar positions. The structure of 4 consists of isolated {V(III)O(6)} octahedra linked by diphosphonate groups into a three-dimensional framework. Crystal data: for 1, CH(6)O(7)P(2)V(0.5)Cs, monoclinic C2, a = 10.991(2) ?, b = 10.161(2) ?, c = 7.445(1) ?, beta = 92.97(3) degrees, Z = 4; for 2, CH(3)O(7)P(2)VCs, monoclinic C2, a = 10.212(2) ?, b = 10.556(2) ?, c = 14.699(3) ?, beta = 94.57(2) degrees, Z = 8; for 3, C(2)H(8)O(16)P(4)V(3)Cs, monoclinic C2/m, a = 9.724(2) ?, b = 8.136(2) ?, c = 10.268(2) ?, beta = 103.75(3) degrees, Z = 2; for 4, CH(5)O(7)P(2)V, monoclinic P2(1)()/n, a = 5.341(1) ?, b = 11.516(2) ?, c = 10.558(2) ?, beta = 99.89(1) degrees, Z = 4.     

Raman spectroscopic study of tungsten(VI) oxosulfato complexes in WO3-K2S2O7-K2SO4 molten mixtures: stoichiometry, vibrational properties, and molecular structure

The dissolution reaction of WO3 in pure molten K2S2O7 and in molten K2S2O7-K2SO4 mixtures is studied under static equilibrium conditions in the XWO3(0) = 0-0.33 mol fraction range at temperatures up to 860 °C. High temperature Raman spectroscopy shows that the dissolution leads to formation of W(VI) oxosulfato complexes, and the spectral features are adequate for inferring the structural and vibrational properties of the complexes formed. The band characteristics observed in the W=O stretching region (band wavenumbers, intensities, and polarization characteristics) are consistent with a dioxo W(=O)2 configuration as a core unit within the oxosulfato complexes formed. A quantitative exploitation of the relative Raman intensities in the binary WO3-K2S2O7 system allows the determination of the stoichiometric coefficient, n, of the complex formation reaction WO3 + nS2O7(2-) --> C(2n-). It is found that n = 1; therefore, the reaction WO3 + S2O7(2-) > WO2(SO4)2(2-) with six-fold W coordination is proposed as fully consistent with the observed Raman features. The effects of the incremental dissolution and presence of K2SO4 in WO3-K2S2O7 melts point to a WO3 · K2S2O7 · K2SO4 stoichiometry and a corresponding complex formation reaction in the ternary molten WO3-K2S2O7-K2SO4 system according to WO3 + S2O7(2-) + SO4(2-) --> WO2(SO4)3(4-). The coordination sphere of W in WO2(SO4)2(2-) (binary system) is completed with two oxide ligands and two chelating sulfate groups. A dimeric [{WO2(SO4)2}2(μ-SO4)2](8-) configuration is proposed for the W oxosulfato complex in the ternary system, generated from inversion symmetry of aWO2(SO4)3(4-) moiety resulting in two bridging sulfates. The most characteristic Raman bands for the W(VI) oxosulfato complexes pertain to W(=O)2 stretching modes (i) at 972 (polarized) and 937 (depolarized) cm(-1) for the ν(s) and ν(as) W(=O)2 modes of WO2(SO4)2(2-), and (ii) at 933 (polarized) and 909 (depolarized) cm(-1) for the respective modes of [{WO2(SO4)2}2(μ-SO4)2](8-).     

Synthesis, Structure and Characterization of [Cu(2,2''-bpy)2][{Cu(2,2''-bpy)2}2W12O40(H2)]·4H2O

An organic-inorganic compound [Cu(2,2'-bpy)2][{Cu(2,2'-bpy)2}2W12O4o(H2)]·4H2O (Mr = 4048.00) was prepared from the hydrothermal reaction of Na2WO4·2H2O, CuCl2·2H2O,2,2'-bipyridine (2,2'-bpy) and H2O at 160 ℃ for 4 days. The compound crystallizes in the monoclinic system, space group P21/n with a = 18.9196(8), b = 20.4212(8), c = 21.8129(9)(A), β=96.992(3)°, V= 8365.0(6) (A)3, Dc= 3.214 g/cm3, Z = 4,μ(MoKα) = 17.269 mm-1 and F(000) = 7324.Of the 119837 total reflections, 17315 were unique (Rint = 0.0489). The final R = 0.0385 and wR =0.0770 for 11142 observed reflections with I ＞ 2σ(I). Single-crystal X-ray diffraction reveals that the structure is composed of [{Cu(2,2'-bpy)2}2W12O40(H2)]2- anions, discrete [Cu(2,2'-bpy)2]2 cations and lattice water molecules, and the anion is made up of a {W12O40(H2)}6- α-Keggin core decorated with two {Cu(2,2'-bpy)2}2 groups through bridging oxygen atoms.     

Synthesis, crystal structures, and properties of oxovanadium(IV)-lanthanide(III) heteronuclear complexes

A new series of oxovanadium(IV)-lanthanide(III) heteronuclear complexes [Yb(H2O)8]2[(VO)2(TTHA)](3)21 H2O (1), {[Ho(H2O)7(VO)2(TTHA)][(VO)2(TTHA)](0.5)} 8.5 H2O (2), {[Gd(H2O)7(VO)2(TTHA)][(VO)2(TTHA)](0.5)}8.5 H2O (3), {[Eu(H2O)7][(VO)2(TTHA)](1.5)} 10.5 H2O (4), and [Pr2(H2O)6(SO4)2][(VO)2(TTHA)] (5) (H6TTHA=triethylenetetraaminehexaacetic acid) were prepared by using the bulky flexible organic acid H(6)TTHA as structure-directing agent. X-ray crystallographic studies reveal that they contain the same [(VO)2(TTHA)]2- unit as building block, but the Ln3+ ion lies in different coordination environments. Although the lanthanide ions always exhibit similar chemical behavior, the structures of the complexes are not homologous. Compound 1 is composed of a [Yb(H2O)8]3+ ion and a [(VO)2(TTHA)]2- ion. Compounds 2 and 3 are isomorphous; both contain a trinuclear [Ln(H2O)7(VO)2(TTHA)]+ (Ln=Ho for 2 and Gd for 3) ion and a [(VO)2(TTHA)]2- ion. Compound 4 is an extended one-dimensional chain, in which each Eu3+ ion links two [(VO)2(TTHA)]2- ions. For 5, the structure is further assembled into a three-dimensional network with an interesting framework topology comprising V2Pr2 and V4Pr2 heterometallic lattices. Moreover, 4 and 5 are the first oxovanadium(IV)-lanthanide(III) coordination polymers and thus enlarge the realm of 3d-4f complexes. The IR, UV/Vis, and EPR spectra and the magnetic properties of the heterometallic complexes were studied. Notably, 2 shows unusual ferromagnetic interactions between the VO2+ and Ho3+ ions.     

Amine-templated linear vanadium sulfates with different chain structures

Amine-templated vanadium sulfates of the formula [HN(CH(2))(6)NH][(V(IV)O)(2)(OH)(2)(SO(4))(2)].H(2)O, I, [H(3)N(CH(2))(2)NH(3)][V(III)(OH)(SO(4))(2)].H(2)O, II, and [H(2)N(CH(2))(4)NH(2)][(V(IV)O)(H(2)O)(SO(4))(2)], III, have been prepared under hydrothermal conditions. These vanadium sulfates add to the new emerging family of organically templated metal sulfates. Compound I has a linear chain structure consisting of V(2)O(8) square-pyramid dimers connected by corner-sharing SO(4) tetrahedra, creating four-membered rings along the chain. Both II and III possess simple linear chain topologies formed by VO(6) octahedra and SO(4) tetrahedra, with II having the tancoite chain structure. Compound I crystallizes in the triclinic space group P1 (No. 2) with a = 7.4852(4) A, b = 9.5373(5) A, c = 11.9177(6) A, alpha = 77.22 degrees, beta = 76.47(2) degrees, gamma = 80.86 degrees, Z = 2. Compound II: monoclinic, space group P2(1)/c (No. 14), a = 6.942(2) A, b = 10.317(3) A, c = 15.102(6) A, beta = 90.64(4) degrees, Z = 4. Compound III: triclinic, space group P1 (No. 2) with a = 6.2558(10) A, b = 7.0663(14) A, c = 15.592(4) A, alpha = 90.46(2) degrees, beta = 90.47(2) degrees, gamma = 115.68(2) degrees, Z = 2. Magnetic susceptibility measurements reveal weak antiferromagnetic interactions in I and III and ferromagnetic interactions in II.     

新型环形聚阴离子[{WO(H_2O)}_3(AsW_8O31)_3]~21-的结构及表征

在pH=3.0的水溶液中，Na_2WO_4·2H_2O与NaAsO_2·6H_2O和NH_4Cl反应，得 到了新的杂多钨酸盐(MH_4)_19Na_2[{WO(H_2O)}_3(AsW_8O31)_3]·45H_2O单晶， 用X射线单晶衍射法及元素分析确定了其结构，晶体属单斜晶系，空间群C2/c，晶 胞参数为：a=3.1165(11)nm, b=1.7388(7)nm, c=2.2789(9)nm, β=97.342(6)°, V=12.248(8)nm~3, Z=4, R_1=0.0571,wR_2=0.0741[I＞2σ(I)]. 环型聚阴离子 [{WO(H_2O)}_3(AsW_8O31)_3]~21-是由三个{WO(H_2O)}桥连三个新发现的 {AsW_8O31}单元构成的，环聚离子[{WO(H_2O)}_3(AsW_8O31)_3]~21-具有近似D_ (3h)对称性。对该化合物还进行了~183W NMR, IR和TG表征。     

Synthesis and Crystal Structure of a Novel Tetravanadate Modified by Chiral Racemoid Zirconium Complex

1 INTRODUCTION Polyoxometalate anions are a broad class of dis- crete metal-oxide compounds MxOyn–, which are of both fundamental and practical interest in a range of areas, including catalysis, biochemistry, medicine and solid state devices[1~6]. Recently, the structural chemistry of vanadium oxides in combination with secondary metal-ligand cations has attracted much attention[7~17]. These hybrid materials manifest the structural influences both of coordination preferen- ces of the sec…     

Large cluster formation through multiple substitution with lanthanide cations (La, Ce, Nd, Sm, Eu, and Gd) of the polyoxoanion

Several new large polyoxotungstates have been synthesized by reaction of lanthanide cations with the well-known "As(4)W(40)" anion, [(B-alpha-AsO(3)W(9)O(30))(4)(WO(2))(4)](28-) (1). The heteropolyanions [(H(2)O)(11)Ln(III)(Ln(III)(2)OH)(B-alpha-AsO(3)W(9)O(30))(4)(WO(2))(4)](20)(-) (Ln = Ce, Nd, Sm, Gd) (2-4) (Ln(3)As(4)W(40)) and [M(m)()(H(2)O)(10)(Ln(III)(2)OH)(2)(B-alpha-AsO(3)W(9)O(30))(4)(WO(2))(4)]((18-m)(-)) (Ln = La, Ce, Gd and M = Ba, K, none) (5-7) (Ln(4)As(4)W(40)) have been isolated as alkali metal and ammonium salts, respectively, and characterized by single-crystal X-ray analysis, elemental analysis, and IR and (183)W-NMR spectroscopy. The X-ray analyses revealed interanionic W-O-Ln bonds between adjacent Ln(x)()As(4)W(40) units forming a "dimer" for x = 3 and chains for x = 4. Upon dissolving in water these bonds hydrolyze and the monomeric species form. The straightforward syntheses which require the use of concentrated NaCl solutions (1-4 M) and the addition of stoichiometric amounts of Ba(2+) or K(+) reemphasize the importance of the presence of appropriate countercations for the assembly of large polyoxometalate structures.     

Electrochemical and chemical formation of [Mn4(IV)O5(terpy)4(H2O)2]6+, in relation with the photosystem II oxygen-evolving center model [Mn2(III,IV)O2(terpy)2(H2O)2]3+

To examine the real ability of the binuclear di-mu-oxo complex [Mn2(III,IV)O2(terpy)2(H2O)2]3+ (2) to act as a catalyst for water oxidation, we have investigated in detail its redox properties and that of its mononuclear precursor complex [Mn(II)(terpy)2]2+ (1) in aqueous solution. It appears that electrochemical oxidation of 1 allows the quantitative formation of 2 and, most importantly, that electrochemical oxidation of 2 quantitatively yields the stable tetranuclear Mn(IV) complex, [Mn4(IV)O5(terpy)4(H2O)2]6+ (4), having a linear mono-mu-oxo{Mn2(mu-oxo)2}2 core. Therefore, these results show that the electrochemical oxidation of 2 in aqueous solution is only a one-electron process leading to 4 via the formation of a mono-mu-oxo bridge between two oxidized [Mn2(IV,IV)O2(terpy)2(H2O)2]4+ species. 4 is also quantitatively formed by dissolution of the binuclear complex [Mn2(IV,IV)O2(terpy)2(SO4)2] (3) in aqueous solutions. Evidence of this work is that 4 is stable in aqueous solutions, and even if it is a good synthetic analogue of the "dimers-of-dimers" model compound of the OEC in PSII, this complex is not able to oxidize water. As a consequence, since 4 results from an one-electron oxidation of 2, 2 cannot act as an efficient homogeneous electrocatalyst for water oxidation. This work demonstrates that a simple oxidation of 2 cannot produce molecular oxygen without the help of an oxygen donor.     

Vanadogermanate cluster anions

Three novel vanadogermanate cluster anions have been synthesized by hydrothermal reactions. The cluster anions are derived from the (V(18)O(42)) Keggin cluster shell by substitution of V=O(2+) "caps" by Ge(2)O(OH)(2)(4+) species. In Cs(8)[Ge(4)V(16)O(42)(OH)(4)].4.7H(2)O, 1, (monoclinic, space group C2/c (No. 15), Z = 8, a = 44.513(2) A, b = 12.7632(7) A, c = 22.923(1) A, beta = 101.376(1) degrees ) and (pipH(2))(4)(pipH)(4)[Ge(8)V(14)O(50).(H(2)O)] (pip = C(4)N(2)H(10)), 2 (tetragonal, space group P4(2)/nnm (No. 134), Z = 2, a = 14.9950(7) A, c = 18.408(1) A), two and four VO(2+) caps are replaced, respectively, and each cluster anion encapsulates a water molecule. In K(5)H(8)Ge(8)V(12)SO(52).10H(2)O, 3, (tetragonal, space group I4/m (No. 87), Z = 2, a = 15.573(1) A, c = 10.963(1) A), four VO(2+) caps are replaced by Ge(2)O(OH)(2)(4+) species, and an additional two are omitted. The cluster ion in 3 contains a sulfate anion disordered over two positions. The cluster anions are analogous to the vanadoarsenate anions [V(18)(-)(n)()As(2)(n)()O(42)(X)](m)(-) (X = SO(3), SO(4), Cl; n = 3, 4) previously reported.     

Synthesis,Structure and Characterization of [Cu(2,2′-bpy)_2][{Cu(2,2′-bpy)_2}_2W_(12)O_(40)(H_2)]·4H_2O

An organic-inorganic compound [Cu(2,2′-bpy)2][{Cu(2,2′-bpy)2}2W12O40(H2)]·4H2O (Mr = 4048.00) was prepared from the hydrothermal reaction of Na2WO4·2H2O, CuCl2·2H2O, 2,2′-bipyridine (2,2′-bpy) and H2O at 160 ℃ for 4 days. The compound crystallizes in the monoclinic system, space group P21/n with a = 18.9196(8), b = 20.4212(8), c = 21.8129(9) , β = 96.992(3)°, V = 8365.0(6) 3, Dc = 3.214 g/cm3, Z = 4, μ(MoKα) = 17.269 mm-1 and F(000) = 7324. Of the 119837 total reflections, 17315 were unique (Rint = 0.0489). The final R = 0.0385 and wR = 0.0770 for 11142 observed reflections with I > 2σ(I). Single-crystal X-ray diffraction reveals that the structure is composed of [{Cu(2,2′-bpy)2}2W12O40(H2)]2- anions, discrete [Cu(2,2′-bpy)2]2+ cations and lattice water molecules, and the anion is made up of a {W12O40(H2)}6- α-Keggin core decorated with two {Cu(2,2′-bpy)2}2+ groups through bridging oxygen atoms.     

Hydrothermal Synthesis and Structure of[{Mo_8V_4O_(36)(VO_4)(VO)_2}n]~(7n-)Bi-capped α-Keggin Fragments Linked to a Chain

The title compound, (H2en)3H3O{Mo8V4O36(VO4) (VO)2} ?4H2O, was hydrothermally synthesized and structurally characterized by means of IR, ESR spectrum and single crystal X-ray diffraction. It crystallized in a monoclinic system with space group P21/c, a=1. 980 4(4) nm, 6=2. 063 4(4) nm, c=l. 192 0(2) nm, =94. 76(3)?and deep black colour. The compound contains V-centered bi-capped a-Keggin fragments {Mo8V7O42} that are linked together by edge-shared units V O5 via V桹梀 bonds, forming a chain.