147977-45-5Relevant academic research and scientific papers
A new synthetic route to W4W and Mo4W compounds of the type MM′X4(PR3)4, X = Cl or Br. Structural characterization of W4WBr4(μ-dppm)2 and Mo4WBr4(PMe2Ph)4 and 31P{1H} NMR spectra of these and related compounds
Cotton,Eglin, Judith L.,James, Chris A.
, p. 681 - 686 (2008/10/08)
A new synthetic route that is more convenient and more general than any previously available has now been developed for quadruply bonded W24+ compounds. This new synthetic route has been used in the preparation of complex 1, W4WBr4(μ-dppm)2, and in addition two known ditungsten compounds, W2Cl4(PMe3)4 (3) and W2Cl4(PMe2Ph)4 (4). The quadruply bonded complexes 1 and Mo4WBr4(PMe2Ph)4 (2) are formed in the reactions between WBr5 and bis(diphenylphosphino)methane and WBr4(PPh3)2 and Mo(η6-C6H5PMe2)(PMe 2Ph)3, respectively. These are the only examples of quadruply bonded complexes that contain either a W4WBr4 or Mo4WBr4 core. The W4W and apparent Mo4W distances for W4WBr4(μ-dppm)2 and Mo4WBr4(PMe2Ph)4 are 2.2632(9) and 2.209(1) A?, respectively. Complex 2 is contaminated by small amounts of the dimolybdenum analog. In addition to the structural data for these complexes, each has been fully characterized using 31P{1H} NMR and UV-vis spectroscopy. Preliminary spectroscopic data have been obtained for W4WBr4(PMe2Ph)4 (5), W4WBr4-(PPh2Me)4 (6), and Mo4WBr4(PPh2Me)4 (7). Complex 1 has methylene protons located at positions that allow the calculation of the diamagnetic anisotropy of the W4W bond from the 1H NMR chemical shift data. The diamagnetic anisotropy for the W4W bond in W4WBr4(μ-dppm)2 has been estimated and will be compared to the diamagnetic anisotropy estimated for W4WCl4(μ-dppm)2 and α-W4WCl4(dppe)2. The crystal structures of 1 and 2 are fully described. Crystallographic data for these compounds are as follows: compound 1, P21 with a = 10.047(1) A?, b = 14.529(2) A?, c = 23.668(3) A?, β = 95.294(1)?, V = 3440(1) A?3, and Z = 2; compound 2, Fdd2 with a = 18.313(4) A?, b = 43.981(7) A?, c = 9.570(2) A?, V = 7709(2) A?3, and Z = 8.
Preparation of W2Cl84- and several of its derivatives
Schrock, Richard R.,Sturgeoff, Lynda G.,Sharp, Paul R.
, p. 2801 - 2806 (2008/10/08)
The sodium amalgam reduction of WCl4 in tetrahydrofuran in the presence of a tertiary phosphine (L = PMe3, PBu3, PMe2Ph, PMePh2) produces a family of compounds of the type W2Cl4L4, which contain a tungsten-tungsten quadruple bond. W2Cl4(dmpe)2 and W2Cl4(dppe)2 must be prepared by the reaction between W2Cl4(PBu3)4 and dmpe or dppe. In the absence of phosphine, WCl4 can be reduced to W2Cl6(THF)4. W2Cl6(THF)4 reacts with phosphine to produce W2Cl6L4, and W2Cl6L4 can be reduced cleanly to W2Cl4L4. In the absence of phosphine W2Cl6(THF)4 can be reduced to deep blue Na4(THF)xW2Cl8. Several other derivatives such as Na4(TMEDA)4W2Cl8 have also been prepared. All derivatives that contain the W2Cl84- ion decompose within a few minutes at 25°C in solvents in which they dissolve. Na4(THF)xW2Cl8 reacts rapidly with phosphine to produce W2Cl4L4, with 6-methyl-2-hydroxypyridine in the presence of triethylamine to produce W2(mhp)4, and with pivalic acid in the presence of triethylamine to produce W2(O2CCMe3)4. We have shown that complexes of the type W2Cl4L4 can be oxidized readily to monocations. An attempt to prepare W2(O2CCH3)4 from W2Cl4(PBu3)4 and acetic acid also led to oxidation of the metal to give W3O3Cl5(O2CCH3)(PBu 3)3.
