邻二硝基二钌取代的多金属氧酸盐γ-[XW10O38{RuN}2]6-（X = Si 或 Ge）。

Vicinal dinitridoruthenium-substituted polyoxometalates gamma-[XW10O38{RuN}2]6- (X = Si or Ge).

机构信息

Institut Parisien de Chimie Moléculaire, UMR CNRS 7201, Case courier 42, UPMC, Paris 06, 4 place Jussieu, 75252 Paris cedex, France.

出版信息

Chemistry. 2009 Oct 5;15(39):10233-43. doi: 10.1002/chem.200900965.

DOI:10.1002/chem.200900965

PMID:19739211

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), 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) 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.

摘要

缺位多金属氧酸盐 K(8)[γ-XW(10)O(36)]（X=Si，Ge）与两当量的金属-亚硝化物前体 Cs(2)[Ru(VI)NCl(5)]在室温下的水中反应，生成 K(2)(Me(2)NH(2))(2)H(2)[γ-XW(10)O(38){RuN}(2)]，X=Si（DMA-1a）或 Ge（DMA-1b）。这两个配合物的 X 射线晶体结构都显示出单体配合物，具有非常不寻常的毗邻终端金属-亚硝化物单元。Ru[三重键]N 键长分别为 1.594(10)和 1.612(11)A 在 1a 和 1b 中。EXAFS 研究证实了 X 射线晶体学的关键结构赋值。DMA-1a 的 XANES 光谱、抗磁性、NMR((29)Si 和(183)W)化学位移、伏安行为、与PW(12)O(40)的还原滴定以及计算数据均与这些配合物中 d(2)Ru(VI)中心一致。FT-IR 和拉曼光谱分别显示了{γ-XW(10)}单元和 Ru[三重键]N 伸缩的预期振动模式，分别在 1080cm(-1)处。有趣的是，通过 4 当量的PW(12)O(40)还原 DMA-1a 可几乎定量地得到 NH(3)。循环伏安法相对于 pH 值和计算为该反应中可能的两电子还原和两质子加成过程提供了能量学。