Dithallium(III)-Containing 30-Tungsto-4-phosphate, [Tl₂Na₂(H₂O)₂(P₂W₁₅O₅₆)₂]^16–: 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 [Tl₂Na₂(H₂O)₂­{P₂W₁₅O₅₆}₂]^16– (<b>1</b>) by a multitude of solid-state and solution techniques. Polyanion <b>1</b> comprises two octahedrally coordinated Tl³⁺ ions sandwiched between two trilacunary {P₂W₁₅} 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 ³¹P and ^203/205Tl NMR. This was also supported by Tl NMR spectra simulations including several spin systems of isotopologues with half-spin nuclei (²⁰³Tl, ²⁰⁵Tl, ³¹P, ¹⁸³W). ²³Na NMR showed a time-averaged signal of the Na⁺ counter cations and the structurally bonded Na⁺ ions. ^203/205Tl NMR spectra also showed a minor signal tentatively attributed to the trithallium-containing derivative [Tl₃Na­(H₂O)₂­(P₂W₁₅O₅₆)₂]^14–, 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>

Synthesis, Structure, and Antibacterial Activity of a Thallium(III)-Containing Polyoxometalate, [Tl₂{<i>B</i>‑β-SiW₈O₃₀(OH)}₂]^12–

We have synthesized and structurally characterized the first discrete thallium-containing polyoxometalate, [Tl₂{<i>B</i>-β-SiW₈O₃₀(OH)}₂]^12– (<b>1</b>). Polyanion <b>1</b> was characterized in the solid-state and shown to be solution-stable by ^203/205Tl NMR, electrospray ionization mass spectrometry, and electrochemical studies. The antibacterial activity of <b>1</b> was also investigated

Mixed-Valent Mn₁₆-Containing Heteropolyanions: Tuning of Oxidation State and Associated Physicochemical Properties

The two 16-manganese-containing, Keggin-based 36-tungsto-4-silicates [Mn^III₁₀Mn^II₆O₆­(OH)₆­(PO₄)₄­(<i>A</i>-α-SiW₉O₃₄)₄]^28– (<b>1</b>) and [Mn^III₄Mn^II₁₂­(OH)₁₂­(PO₄)₄­(<i>A</i>-α-SiW₉O₃₄)₄]^28– (<b>2</b>) have been prepared by reaction of the trilacunary Keggin precursor [<i>A</i>-α-SiW₉O₃₄]^10– with either Mn­(OOCCH₃)₃·2H₂O (for <b>1</b>) or MnCl₂·4H₂O (for <b>2</b>), in aqueous phosphate solution at pH 9. Polyanions <b>1</b> and <b>2</b> comprise mixed-valent, cationic {Mn^III₁₀Mn^II₆O₆­(OH)₆}²⁴⁺ and {Mn^III₄Mn^II₁₂­(OH)₁₂}²⁴⁺ cores, respectively, encapsulated by four phosphate groups and four {SiW₉} units in a tetrahedral fashion. Both polyanions were structurally and compositionally characterized by single-crystal XRD, IR, thermogravimetric analysis, and X-ray absorption spectroscopy. Furthermore, studies were performed probing the magnetic, electrochemical, oxidation catalytic, and Li-ion battery performance of <b>1</b> and <b>2</b>