title: Vicinal dinitridoruthenium-substituted polyoxometalates gamma-[XW10O38{RuN}2]6- (X = Si or Ge).
abstract: Reaction of the divacant polyoxometalate K(8)[gamma-XW(10)O(36)] (X = Si, Ge) with two equivalents of the metal-nitrido precursor Cs(2)[Ru(VI)NCl(5)], at room temperature in water, produces K(2)(Me(2)NH(2))(2)H(2)[gamma-XW(10)O(38){RuN}(2)], X = Si (DMA-1 a) or Ge (DMA-1 b). The X-ray crystal structures of both complexes show monomeric complexes with highly unusual vicinal terminal metal-nitrido units. The Ru[triple bond]N bond lengths are 1.594(10) and 1.612(11) A in 1 a and 1 b, respectively. EXAFS studies confirmed the key structural assignments from X-ray crystallography. The XANES spectrum of DMA-1 a, diamagnetism, NMR ((29)Si and (183)W) chemical shifts, voltammetric behavior, reductive titrations with [PW(12)O(40)](4-), and computational data are all consistent with d(2) Ru(VI) centers in these complexes. The FT-IR and Raman spectra show the expected vibrational modes of the {gamma-XW(10)} unit and the Ru[triple bond]N stretch at 1080 cm(-1), respectively. Interestingly, reduction of DMA-1 a by 4 equivalents of [PW(12)O(40)](4-) produces NH(3) in nearly quantitative yield. Cyclic voltammetry versus pH and calculations provide the energetics for the possible two-electron reduction and two-proton addition processes in this reaction.
authors.affiliation: Institut Parisien de Chimie Moléculaire, UMR CNRS 7201, Case courier 42, UPMC, Paris 06, 4 place Jussieu, 75252 Paris cedex, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Besson
authors.forename: Djamaladdin G
authors.initials: DG
authors.lastname: Musaev
authors.forename: Vanina
authors.initials: V
authors.lastname: Lahootun
authors.forename: Rui
authors.initials: R
authors.lastname: Cao
authors.forename: Lise-Marie
authors.initials: LM
authors.lastname: Chamoreau
authors.forename: Richard
authors.initials: R
authors.lastname: Villanneau
authors.forename: Françoise
authors.initials: F
authors.lastname: Villain
authors.forename: René
authors.initials: R
authors.lastname: Thouvenot
authors.forename: Yurii V
authors.initials: YV
authors.lastname: Geletii
authors.forename: Craig L
authors.initials: CL
authors.lastname: Hill
authors.forename: Anna
authors.initials: A
authors.lastname: Proust