Determination of alpha -Keggin structure of [GeW sub(11)O sub(39)Ru super(III)(H sub(2)O)] super(5-). Reaction of [GeW sub(11)O sub(39)Ru super(III)(H sub(2)O)] super(5-) with dimethyl sulfoxide to form [GeW sub(11)O sub(39)Ru super(III)(dmso)] super(5-) and their structural characterization

Reaction of ruthenium super((III))-substituted Keggin-type germanotungstate [GeW sub(11)O sub(39)Ru super(III)(H sub(2)O)] super(5-) (1) with a dimethyl sulfoxide (dmso) produced a dmso-coordinating derivative [GeW sub(11)O sub(39)Ru super(III)(dmso)] super(5-) (2). Structural characterization of compound 2 by using cyclic voltammetry, UV-Vis spectroscopy, IR spectroscopy, elemental analysis, super(1)H-NMR spectroscopy and single crystal structure analysis (monoclinic, P2 sub(1)/c, a= 13.461(1), b= 20.198(1), c= 18.078(1), beta = 90.426(1), Z= 4) revealed that Ru super(III) was incorporated in the alpha -Keggin-type framework and coordinated by dmso through an Ru-S bond. The IR spectra of 1 and 2 were very similar, indicating that 1 also has an alpha -Keggin structure. Cyclic voltammetry indicated that the incorporated Ru super(III)-dmso was reversibly reduced to the Ru super(II)-dmso derivative and oxidized to the Ru super(IV)-dmso derivative. The redox potential in [ alpha -XW sub(11)O sub(39)Ru super(III/II)(dmso)] super(n-) (X = P, Ge, Si) decreased in the order of P > Ge > Si. Reaction of the complex 2 with ascorbic acid produced a one-electron-reduced compound [ alpha -GeW sub(11)O sub(39)Ru super(II)(dmso)] super(6-).