10 research outputs found
Fast Microwave-Assisted Synthesis of Wells-Dawson-Type 18-Tungsto-2-Phosphate [P<sub>2</sub>W<sub>18</sub>O<sub>62</sub>]<sup>6−</sup>
We report on a fast microwave-assisted synthetic procedure of the Wells-Dawson-type 18-tungsto-2-phosphate [P2W18O62]6− with a 35% yield in 24 h, rather than a week using conventional heating
15-Copper(ii)-containing 36-tungsto-4-silicates(iv) [Cu15O2(OH)(10)X(A--SiW9O34)(4)](25-) (X = Cl, Br): synthesis, structure, magnetic properties, and electrocatalytic CO2 reduction
The 15-copper(ii)-containing 36-tungsto-4-silicates [Cu15O2(OH)(10)X(A--SiW9O34)(4)](25-) (X = Cl, 1; Br, 2) have been prepared in 70% yield by reaction of the trilacunary 9-tungstosilicate precursor [A--SiW9O34](10-) with Cu2+ ions in aqueous pH 8 medium. Both polyanions 1 and 2 were isolated as hydrated mixed potassium/sodium salts and characterized in the solid state by FT-IR, TGA, single-crystal XRD, and elemental analysis. DC magnetic susceptibility measurements from 1.8-300 K established the ground state to be paramagnetic with a magnetic moment corresponding to 15 uncoupled Cu2+ (S = 1/2) ions. EPR measurements and simulations were consistent with this analysis. Electrochemical studies were performed for polyanions 1 and 2 dissolved in solution to elucidate the electroactivity of both copper and tungstate sites. Using 2 as a representative example, the electrocatalytic activity towards CO2 reduction upon deposition on a glassy carbon electrode surface, while retaining selectivity relative to hydrogen evolution, was demonstrated.</p
Dithallium(III)-Containing 30-Tungsto-4-phosphate, [Tl<sub>2</sub>Na<sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>(P<sub>2</sub>W<sub>15</sub>O<sub>56</sub>)<sub>2</sub>]<sup>16–</sup>: Synthesis, Structural Characterization, and Biological Studies
Here
we report on the synthesis and structural characterization of the
dithallium(III)-containing 30-tungsto<i>-</i>4-phosphate
[Tl<sub>2</sub>Na<sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>{P<sub>2</sub>W<sub>15</sub>O<sub>56</sub>}<sub>2</sub>]<sup>16–</sup> (<b>1</b>) by a multitude of solid-state and solution techniques.
Polyanion <b>1</b> comprises two octahedrally coordinated Tl<sup>3+</sup> ions sandwiched between two trilacunary {P<sub>2</sub>W<sub>15</sub>} Wells–Dawson fragments and represents only the second
structurally characterized, discrete thallium-containing polyoxometalate
to date. The two outer positions of the central rhombus are occupied
by sodium ions. The title polyanion is solution-stable as shown by <sup>31</sup>P and <sup>203/205</sup>Tl NMR. This was also supported by
Tl NMR spectra simulations including several spin systems of isotopologues
with half-spin nuclei (<sup>203</sup>Tl, <sup>205</sup>Tl, <sup>31</sup>P, <sup>183</sup>W). <sup>23</sup>Na NMR showed a time-averaged signal
of the Na<sup>+</sup> counter cations and the structurally bonded
Na<sup>+</sup> ions. <sup>203/205</sup>Tl NMR spectra also showed
a minor signal tentatively attributed to the trithallium-containing
derivative [Tl<sub>3</sub>Na(H<sub>2</sub>O)<sub>2</sub>(P<sub>2</sub>W<sub>15</sub>O<sub>56</sub>)<sub>2</sub>]<sup>14–</sup>, which could also be identified in the solid state by single-crystal
X-ray diffraction. The bioactivity of polyanion <b>1</b> was
also tested against bacteria and <i>Leishmania</i>