Syntheses and Characterization of γ-[SiW₁₀M₂S₂O₃₈]^6- (M = Mo^V, W^V). Two Keggin Oxothio Heteropolyanions with a Metal−Metal Bond

Abstract

The oxothio polyanions gamma-[SiW(10)M(2)S(2)O(38)](6)(-) (M = Mo(V), W(V)) were obtained through stereospecific addition of the dication [M(2)S(2)O(2)](2+) (M = Mo, W) to the divacant gamma-[SiW(10)O(36)](8)(-) anion in dimethylformamide. These compounds were isolated as crystals and are stable in usual organic solvents and in aqueous medium from pH = 1 to pH = 7. NEt(4)Cs(3)H(2)[SiW(10)Mo(2)S(2)O(38)].6H(2)O (a gamma-isomer derived from the alpha Keggin structure capped by the [Mo(2)S(2)O(2)](2+) fragment containing a metal-metal bond) crystallizes in the triclinic space group P&onemacr; with a = 12.050(3) Å, b = 12.695(2) Å, c = 20.111(4) Å, alpha = 74.35(2) degrees, beta = 86.83(2) degrees, gamma = 63.50(2) degrees, Z = 2. NEt(4)Cs(5)[SiW(12)S(2)O(38)].7H(2)O is isostructural and crystallizes in the triclinic space group P&onemacr; with a = 12.197(4) Å, b = 12.714(3) Å, c = 20.298(3) Å, alpha = 74.75(1) Å, beta = 86.48(2) degrees, gamma = 61.80(2) degrees, Z = 2. (183)W NMR spectra of Li(+) salts in aqueous solution agree with the solid state structures and reveal 100% purity for both anions. Polarographic, infrared and UV-vis data are also given.

Structural and Magnetic Properties of MnIII and CuII Tetranuclear Azido Polyoxometalate Complexes: Multifrequency High‐Field EPR Spectroscopy of Cu4 Clusters with S=1 and S=2 Ground States

“…Synthesis: Complexes 1 a and 2 a were synthesized at room temperature in acetonitrile/methanol media by mixing the divacant [N(C 4 H 9 ) 4 ] 4 H 4 [g-SiW 10 O 36 ] precursor [18] with two equivalents of the transition-metal acetate salt and an excess of NaN 3 . In both cases, a relatively abundant powder was obtained after addition of tetraethylammonium bromide.…”

Synthesis, Structure, and Behavior in Solution of the Dawson Thio Derivative [(P2W17O61)2(H4Mo4S4O6)]16–

“…A fruitful approach to the synthesis of sulfur-containing polyoxometalates has been developed that involves treating the electrophilic core {Mo 2 O 2 S 2 } 2+ with vacant polyoxotungstate ions. [23][24][25][26][27] With regard to the potential of the method and the growth of interest in such compounds, this field of investigation continues to be one of our main focuses. We present herein the synthesis and characterization in the solid state and solution of the oxothio heteropolyanion obtained from the direct addition of the dication {Mo 2 …”

A Supramolecular Tetra‐Dawson Polyoxothiometalate: [(α‐H2P2W15O56)4{Mo2O2S2(H2O)2}4{Mo4S4O4(OH)2(H2O)}2]28−

“…[3] Several polyoxothioanions have been prepared by this way, the architecture of the resulting oxothio compounds is mainly governed by the stereochemistry of the parent lacunary polyanion. [4] Herein, we report the structural and multinuclear NMR spectroscopic characterization [5] with the trivacant Dawson anion a-[P 2 W 15 O 56 ] 12À (30 % yield).…”