10.1021/om980288p.s002
John William Benson
John William
Benson
Richard L. Keiter
Richard L.
Keiter
Ellen A. Keiter
Ellen A.
Keiter
Arnold L. Rheingold
Arnold L.
Rheingold
Glenn P. A. Yap
Glenn
P. A. Yap
Vera V. Mainz
Vera V.
Mainz
Studies of a Reluctant Ligand. An X-ray
Crystallographic and NMR Spectroscopic Analysis of
(OC)<sub>5</sub>W(η<sup>1</sup>-PPh<sub>2</sub>CH<sub>2</sub>PPh<sub>2</sub>) and Its
(OC)<sub>5</sub>W(μ-PPh<sub>2</sub>CH<sub>2</sub>PPh<sub>2</sub>)W(CO)<sub>5</sub> Derivative
American Chemical Society
1998
Ph 2 PCH 2 PPh 2
OC
ligand conformation change
2 J PP
NMR Spectroscopic Analysis
5 WNH 2 Ph
4 J PC
1 H
Tungsten pentacarbonyl complexes
PPh 2 CH 2 PPh 2
1998-08-19 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Studies_of_a_Reluctant_Ligand_An_X-ray_Crystallographic_and_NMR_Spectroscopic_Analysis_of_OC_sub_5_sub_W_sup_1_sup_-PPh_sub_2_sub_CH_sub_2_sub_PPh_sub_2_sub_and_Its_OC_sub_5_sub_W_-PPh_sub_2_sub_CH_sub_2_sub_PPh_sub_2_sub_W_CO_sub_5_sub_Derivative/3782424
Tungsten pentacarbonyl complexes, (OC)<sub>5</sub>W(η<sup>1</sup>-PPh<sub>2</sub>CH<sub>2</sub>PPh<sub>2</sub>) (<b>1</b>) and (OC)<sub>5</sub>W(μ-PPh<sub>2</sub>CH<sub>2</sub>PPh<sub>2</sub>)W(CO)<sub>5</sub> (<b>2</b>), have been synthesized from (OC)<sub>5</sub>WNH<sub>2</sub>Ph and Ph<sub>2</sub>PCH<sub>2</sub>PPh<sub>2</sub>
in toluene, and their solid-state structures have been determined by single-crystal X-ray
diffraction. The lone pair of electrons on the dangling phosphine in <b>1</b> is oriented toward
the W(CO)<sub>5</sub> unit in the solid state, and <sup>13</sup>C{<sup>1</sup>H} and <sup>31</sup>P{<sup>1</sup>H} NMR data suggest that this
conformation may also be dominant in solution. Phosphorus−phosphorus coupling in <b>1</b> (<sup>2</sup><i>J</i><sub>PP</sub>
= 106 Hz) is significantly larger than in any previously reported complex of Ph<sub>2</sub>PCH<sub>2</sub>PPh<sub>2</sub>
and is highly dependent on changes in temperature and solvent. Also observed is an
unprecedented long-range phosphorus−carbon coupling (<sup>4</sup><i>J</i><sub>PC</sub> = 3.0 Hz) between the dangling
phosphine and the equatorial carbonyl carbons of <b>1</b>, which is attributed to a conformational
and/or “through-space” enhancement. On the basis of the structural and spectral data, the
reluctance of <b>1</b> to react with (OC)<sub>5</sub>WNH<sub>2</sub>Ph to give <b>2</b> is explained in terms of the substantial
ligand conformation change required.