Dithallium(III)-Containing 30-Tungsto-4-phosphate, [TlNa(HO)(PWO)]: Synthesis, Structural Characterization, and Biological Studies.

Here we report on the synthesis and structural characterization of the dithallium(III)-containing 30-tungsto -4-phosphate [TlNa(HO){PWO}] (1) by a multitude of solid-state and solution techniques. Polyanion 1 comprises two octahedrally coordinated Tl ions sandwiched between two trilacunary {PW} 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 P and Tl NMR. This was also supported by Tl NMR spectra simulations including several spin systems of isotopologues with half-spin nuclei (Tl, Tl, P, W). Na NMR showed a time-averaged signal of the Na counter cations and the structurally bonded Na ions. Tl NMR spectra also showed a minor signal tentatively attributed to the trithallium-containing derivative [TlNa(HO)(PWO)], which could also be identified in the solid state by single-crystal X-ray diffraction. The bioactivity of polyanion 1 was also tested against bacteria and Leishmania.