Recent perspectives into biochemistry of decavanadate

The number of papers about decavanadate has doubled in the past decade. In the present review, new insights into decavanadate biochemistry, cell biology, and antidiabetic and antitumor activities are described. Decameric vanadate species (V10) clearly differs from monomeric vanadate (V1), and affects differently calcium pumps, and structure and function of myosin and actin. Only decavanadate inhibits calcium accumulation by calcium pump ATPase, and strongly inhibits actomyosin ATPase activity (IC50 = 1.4 μmol/L, V10), whereas no such ef- fects are detected with V1 up to 150 μmol/L; prevents actin polymerization (IC50 of 68 μmol/L, whereas no effects detected with up to 2 mmol/L V1); and interacts with actin in a way that induces cysteine oxidation and vanadate reduction to vanadyl. Moreover, in vivo decavanadate toxicity studies have revealed that acute exposure to polyoxovanadate induces different changes in antioxidant enzymes and oxidative stress parameters, in comparison with vanadate. In vitro studies have clearly demonstrated that mitochondrial oxygen consumption is strongly affected by decavanadate (IC50, 0.1 μmol/L); perhaps the most relevant biological effect. Finally, decavanadate (100 μmol/L) increases rat adipocyte glucose accumulation more potently than several vanadium complexes. Preliminary studies sug- gest that decavanadate does not have similar effects in human adipocytes. Although decavanadate can be a useful biochemical tool, further studies must be carried out before it can be conf irmed that decavanadate and its complexes can be used as anticancer or antidiabetic agents.

Synthesis,Crystal Structure and Properties of a Novel Decavanadate Complex with One-dimensional Chain Involving Sodium and 'Bis-tris' Ligand

By using a flexible multidentate ligand,bis（2-hydroxyethyl）iminotris（hydroxyhydroxylmethy）methane（＇bis-tris＇：H5L）,the title complex {[Na（H6L）2]2}n·nV10O28（1） has been successfully synthesized under self-assembly condition and characterized by IR spectroscopy,elemental analysis,PXRD and single-crystal X-ray diffraction.The crystal structure belongs to an orthorhombic system,space group Cmca with a = 23.752（2）,b = 13.5360（8）,c = 18.5377（11） ,V = 5960.1（7）,Z = 8,Dc = 2.055 g/cm3,F（000） = 3744,μ = 1.630 mm-1,the final R = 0.0283 and wR = 0.0759 for 3353 observed reflections with I 〉 2σ（I）.This complex consists of decavanadate [V10O28]6-motifs as counter anions intercalated with one-dimensiond chains of the composition [Na（H6L）2]n3n＋.And significant intermolecular O-H…O hydrogen-bonding interactions lead to a three-dimensional supramolecular framework.

A Three-dimensional Organic-inorganic Hybrid Material Supported by Decavanadate Clusters and Na-O Chains: Synthesis and Crystal Structure of [Na_6(H_2O)_(16)(dod)_4V_(10)O_(28)]

A new organic-inorganic hybrid material [Na6(H2O)16(dod)2V10O28] (dod = 1,4- diazoniabicyclo[2,2,2]octane-1,4-diacetate) has been synthesized and X-ray single-crystal structural analysis reveals it crystallizes in triclinic, space group P with a = 11.533(7), b = 12.031(7), c = 12.187(4) ? a = 72.47(1), b = 73.16(1), g = 68.21(1)o, C20H64N4Na6O52V10, V = 1467(1) ?, Z = 1, Mr = 1840.1, Dc = 2.083 g/cm3, MoKa, l = 0.71073 ? m = 1.686, F(000) = 924, S = 1.027, the final R = 0.0538 and wR = 0.1272 for 4398 observed reflections. The compound has a three-dimensional frame- work constructed from decavanadate clusters, NaO chains and dod ligands. A variety of OH…O and CH…O hydrogen bonds play an important role in stabilizing the framework.

Synthesis and Crystal Structure of a 3-D Hydrogen-bonded Supramolecular Decavanadate Compound [Habo]_6[V_(10)O_(28)]·2C_3H_7OH·2H_2O

A new inorganic-organic hybrid supramolecular compound [Habo]6[V10O28]·2C3H7OH·2H2O 1 （abo = R（-）-2-amino-1-butanol） has been synthesized from VO2^＋ in organic solvents and its crystal structure was reported as follows： monoclinic, space group P21/n, a = 11.419（9）, b = 16.811（16）, c = 15.521（12） A, β= 102.98（2）°, V= 2903（4） A^3, Z = 4, C15H46N3O19V5, Mr = 827.25, Dc = 1.893 g/cm^3, 2（MoKα） = 0.71073 A, μ = 1.636 mm^-1, F（000） = 1696, the final R = 0.0696 and wR = 0.1361 for 4641 observed reflections with I 〉 2σ（I）. The compound is based on decavanadate clusters [V10O28]^6-. The hydrogen bonding interactions among Habo^＋ cations, solvents and decavanadate clusters extend 1 into a three-dimensional supramolecular architecture.

Preparation and Crystal Structure of a Rare-earth Salt Based on the Decavanadate (V_(10)O_(28)^(6-)): [Y(H_2O)_8]_2[V_(10)O_(28)]·9H_2O

The salt, [Y（H2O）8]2[V10O28]·9H2O, contains two discrete water-groups coordinated Y（Ⅲ） cations, an isopoly complex ion, decavanadate （V10O28^6-） and nine additional water molecules, which are combined together by static electric forces and hydrogen bonds. The y^3＋ is eight-coordinated with a square antiprism geometry. The single-crystal X-ray analysis reveals that the crystal crystallizes in triclinic, space group P1^- with a = 9.1454 （18）, b = 10.007（2）, c = 12.772（3） A°, α= 68.86（3）, β = 77.50（3）, γ= 89.23（3）°, V= 1061.7（4）A°^3 and Z= 1.

Crystal Structure of Dodecaaminium Didecavanadate Dodecahydrate

NH_4)_(12)(V_(10)O_(28))_2·(H_2O)_(12)M_r=2347. 44 , triclinic, P1, a=10. 155 (1), b=10. 286(3) , c=16. 732(9) A, a=96. 50(4), β=87.18(4),γ=108. 99 (1)°, V=1642(4) A ￣3, Z=1, D_c=2. 37 g/cm￣3, F(000)=1160,λ(MoKa)=0. 71069 A, μ=27. 43 cm￣(-1), T= 23℃,final R=0.040 and R_w=0. 058 for 4415 observatives reflections with I≥3σ(I).The title compound contains two (V_(10)O_(28))￣(-6) anions, twelve NH ions and twelve water molecules.The decavanadate anion is an isolated group consisting of ten condensed VO_6 octahedra sharing edges. The anions and the water molecules as well as the cations and the water molecules are connected by the strong hydrogen bonds (the distances are in the range of 2. 758～2. 956 A ).the anions and the cations are connected by the strong hydrogen bonds (2. 720～2. 859A) and the electrostatic force.

Synthesis and Crystal Structure of a Novel Compound of (C_2N_2H_8O_2) H_6V_(10)O_(28)

A novel vanadate decamer, involving all vanadium atoms present in +5 oxidation and one formhydroxamic acid dimer cation readical, has been synthesized. The single-crystal X-ray diffraction shows that the orange crystal is formed in the triclinic system, space group Pi, a = 8. 4960 (17), b = 10.447 (2), c = 11.299 (2) A, α= 68. 82 (3)°,β= 87.35 (3)°, γ = 66.97(3)°. V = 855. 3(3) A3, Z = 8, R1 = 0. 0857, wR2=0. 2551. X-ray crystallographic and packing in superlattice studies showed that the crystal structure was constructed by electrostatic attraction of O-H…O hydrogen bonds between formhydroxamic acid dimer cation and decavanadate polyanion. Formhydroxamic acid dimer is got through controlling the condition of the reaction using formhydroxamic acid.

Preparation, Crystal Structure and Spectroscopy Characterization of Vanadium(V) Complex, 2-Amino-4-Picolinium, 2-Methylimidazolium Decavanadate Hydrate (C₄N₂H7)₄(C₆N₂H₁₀)V₁₀O₂₈·2H₂O

A new decavanadate, (C4N2H7)4(C6N2H10)V10O28·2H2O, was synthesized by slow evaporation at room temperature and characterized by single crystal X-ray diffraction, IR and UV-Vis spectroscopies. The compound crystallizes in the triclinic system, P-1 space group with the cell parameters: a = 11.200(5) Å, b = 12.056(9) Å, c =20.511(7) Å, α = 73.40(4), β = 84.67(3), γ = 63.51(5), Z = 2 and volume V = 2373.7(1) Å3. The formula unit is composed of one decavanadate [V10O28]6- anion, four 2-methylimidazolium (C4N2H7)+ cations, one 2-amino-4-picolinium (C6N2H10)2+ cation and two water molecules. In the crystal, the layers of decavanadate groups, organic cations and water molecules stack up parallel to the (011) plane. The cohesion is provided by N-H···O, O-H···O hydrogen bonds and Van der Waals interactions leads to a three-dimensional structure. The absorbance spectrum measurement shows an optical band gap of 3.27 eV which allows us to conclude that this compound is a semiconductor material.