TUNGSTEN-TUNGSTEN TRIPLE BOND .8. DINUCLEAR ALKOXIDES OF TUNGSTEN(III) AND STRUCTURAL CHARACTERIZATION OF HEXAISOPROPOXYBIS(PYRIDINE)DITUNGSTEN, THE 1ST COMPOUND WITH 4-COORDINATED TUNGSTEN ATOMS UNITED BY A TRIPLE BOND

W2(NMe2)6reacts with t-BuOH and Me3SiOH to yield the crystalline compounds W2(OBu-t)6and W2(OSiMe3)6(HNMe2)2, respectively. The tungsten compounds, unlike their molybdenum analogues, are thermally unstable and cannot be sublimed in vacuo. The thermal decomposition which occurs in vacuo appears to be autocatalytic and not stoichiometric. The reaction between W2(NMe2)6and the less bulky alcohols i-PrOH and Me3CCH2OH leads to polynuclear products; this is in contrast to the analogous reactions involving Mo2(NMe2)6which yield (RO)3Mo≡Mo(OR)3compounds. In pyridine solution W2(NMe2)6reacts with i-PrOH to give the black crystalline compound W2(OPr-i)6(py)2which has been characterized by IR, NMR, and mass spectroscopy and a single-crystal X-ray diffraction study. In the crystalline state the molecular structure contains two W(OPr-i)3py units linked by a W-W triple bond with a length of 2.332 (1) Å. The rotational conformation is roughly halfway between staggered and eclipsed, and the two pyridine ligands are adjacent to each other. Low-temperature 13C NMR spectra support the view that this structure is also present in solution. The crystallographic data are space group P21a = 10.022 (2) Å, b = 17.839 (4) Å, c = 11.946 (2) Å, 0 = 125.57 (1)°;, V= 1737.1 (6) Å3, and Z = 2. © 1979, American Chemical Society. All rights reserved.