81293-90-5Relevant academic research and scientific papers
Improved synthesis, chemistry, and X-ray and neutron diffraction studies of [(Ph3P)2N]+2[H2W 2(CO)8]2-
Wei, Chiau-Y.U.,Marks, Melodye W.,Bau, Robert,Kirtley, Stephen W.,Bisson, Denise E.,Henderson, Margaret E.,Koetzle, Thomas F.
, p. 2556 - 2565 (2008/10/08)
The compound [(Ph3P)2N]+2[H2W 2(CO)8]2- has been synthesized in 65% yield from the reaction of [(Ph3P)2N]+[BH4]- with [(Ph3P)2N]+[W(CO)5(I)]- in refluxing THF. The dianion reacts with BH3·THF in THF to produce [(Ph3P)2N]+[W(CO)4(BH 4)]- in 60% yield. The structure of [(Ph3P)2N]+2[H2W 2(CO)8]2- has been studied with X-ray and neutron diffraction techniques at room temperature and 28 K, respectively. The [H2W2(CO)8]2- anion has approximately D2h symmetry with a planar W(μ-H)2W bridge, confirming the earlier X-ray results by Churchill and co-workers on [Et4N]+2[H2W2(CO) 8]2-. In the [(Ph3P)2N]+ salt, the anions are situated on crystallographic inversion centers, and distances and angles in the W(μ-H)2W core are as follows: W-H = 1.920 (3) and 1.933 (2) A?, W?W = 3.010 (2) A?, H?H = 2.405 (3) A?, W-H-W = 102.7 (1)°, H-W-H = 77.3 (1)°, and H-W-W = 38.78 (6) and 38.48 (6)°. The two bridging H atoms are displaced slightly from the intersections of the trans CO-metal vectors in the direction of the metal-metal axis. The [(Ph3P)2N]+ cation has the usual bent P-N-P configuration, but the phenyl rings are in an uncommon staggered conformation. Crystal data from the neutron diffraction analysis of [(Ph3P)2N]+2[H2W 2(CO)8]2- at 28 K: space group P1; a = 12.949 (1), b = 13.871 (2), c = 11.000 (1) A?; α = 110.828 (8), β = 105.788 (9), γ = 69.334 (8)°; V = 1703.4 (4) A?3; Z = 1. Final agreement factors were R(F) = 0.027 for 5206 neutron reflections with I ≥ σ(I) and R(F) = 0.040 for 4238 X-ray reflections with I ≥ 3σ(I).
