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Keywords:

  • Polyoxometalates;
  • Electrochemistry;
  • Ruthenium;
  • Tungsten;
  • Organo­metallic chemistry

Abstract

A family of {Ru(arene)}2+-containing heteropolytungstates of general formula [{Ru(L)}2(α-XW11O39)2WO2]m (L = benzene, p-cymene; X = GeIV, SiIV, m = 10; X = BIII, m = 12) has been prepared in aqueous acidic medium (pH ≈ 4). The 1:1 interaction of [Ru(C6H6)Cl2]2 or [Ru(p-cymene)Cl2]2 with [β2-GeW11O39]8– led to the formation of [{Ru(benzene)}2(GeW11O39)2WO2]10– (1) and [{Ru(p-cymene)}2(GeW11O39)2WO2]10– (2), respectively. Replacing [β2-GeW11O39]8– by [α-SiW11O39]8– resulted in [{Ru(benzene)}2(SiW11O39)2WO2]10– (3) and [{Ru(p-cymene)}2(SiW11O39)2WO2][SiW12O40]0.512– (4), respectively. The reaction of [α-HBW11O39]8– with the respective {Ru(arene)}2+-containing precursors resulted in polyanions [{Ru(benzene)}2(HBW11O39)2WO2]10– (5) and [{Ru(p-cymene)}2(HBW11O39)2WO2]10– (6), respectively. Single-crystal XRD analysis of the hydrated salts of 16 revealed that these species comprise two Keggin fragments, [{Ru(L)}α-XW11O39]6– (L = benzene, p-cymene; X = GeIV, SiIV) for polyanions 14 and [{Ru(L)}α-HBW11O39]6– (L = benzene, p-cymene) for 5 and 6, connected via a cis-dioxo {WO2}2+ unit. In addition, the heteropolytungstates were characterized by thermogravimetric analysis, IR spectroscopy, elemental analysis, and solution electrochemical studies.