Synthesis and characterization of a monoruthenium(III)-substituted Dawson polyoxotungstate derived by Br2oxidation of the 1 ∶ 2 complex of ruthenium(II) and [α2-P2W17O61]10−. The reactivity of cis-[RuCl2(DMSO)4] as a ruthenium source

Abstract

Synthesis and characterization of the monoruthenium(III)-substituted Dawson polyoxotungstate K₇[α₂-P₂W₁₇O₆₁Ru^III(H₂O)]·19H₂O 2, expected to be an effective homogeneous oxidation catalyst precursor, is described. The reaction products of cis-[Ru^IICl₂(DMSO)₄] as the ruthenium source with mono-lacunary Dawson polyoxotungstate have been examined. By 5 h reaction of cis-[Ru^IICl₂(DMSO)₄] with K₁₀[α₂-P₂W₁₇O₆₁] in ice-cooled, HCl-acidic aqueous solution, a water-soluble 1 ∶ 2-type diamagnetic ruthenium(II) complex, with formula K₁₈[Ru^II(DMSO)₂(P₂W₁₇O₆₁)₂]·35H₂O 1, was unexpectedly obtained as an analytically pure, homogeneous tan-colored solid, in which two DMSO molecules are coordinated to the ruthenium(II) atom. By Br₂ oxidation of 1, the 1 ∶ 1-type paramagnetic complex 2 was obtained as a black crystalline solid. Characterization of 1 and 2 has been carried out with complete elemental analysis, thermogravimetric and differential thermal analyses (TG/DTA), FT-IR, magnetic susceptibility measurements, cyclic voltammetry, UV-vis absorption and ³¹P and ¹⁸³W NMR spectroscopies, as well as ¹H and ¹³C NMR for 1.