Induced Acceleration of Phosphine Exchange in Metal Carbonyls by Pendant Groups of Coordinated Polyphosphines. Two Dangling Phosphine Arms Are Much Better Than One<sup>1</sup>
作者:Richard L. Keiter、John William Benson、Ellen A. Keiter、Weiying Lin、Zhongjiang Jia、Donna M. Olson、Douglas E. Brandt、Jeremy L. Wheeler
DOI:10.1021/om980289h
日期:1998.9.1
dangling phosphines is faster than chelation for each of the four complexes, but chelation of 1 or 2 is much faster than chelation of 3 or 4. It appears that the second danglingphosphine arm present in 1 and 2 accelerates the exchange of all metal-attached ligands. Also observed is long-range phosphorus−carbon coupling, possibly enhanced by a “through-space” interaction, between the short-armed dangling
Dangling phosphine complexes: Phosphine exchange in pentacarbonyl tungsten complexes of bis(diphenylphosphinomethyl)phenylphosphine
作者:Chaminda P. Gamage、Ryan C. Bailey、Ellen A. Keiter、John R. Kuczynski、Kraig A. Wheeler、Charlotte L. Stern、Douglas E. Brandt、Richard L. Keiter
DOI:10.1016/j.jorganchem.2015.07.017
日期:2015.10
6b/6a in CDCl3 at 55 °C. Under the same conditions, the rate of isomerization of 6a to 6b is 4.32 × 10−6 s−1. Isomerization is thought to proceed by an initial attack of a carbonyl group by a pendant phosphine followed by ring opening and a 1,2-phosphine shift. At higher temperatures, chelated complexes with four- and six-membered rings are formed: [(OC)5Wμ-κ1-, κ2-PPh2CH2 (PhPCH2PPh2)W(CO)4 }] 9a, [(OC)5Wμ-κ1-
Intramolecular exchange of coordinated and dangling phosphines in pentacarbonyl group 6 complexes of 1,1,2-tris(diphenylphosphino)ethane
作者:Richard L. Keiter、Ping Ye、Ellen A. Keiter、John William Benson、Weiying Lin、Douglas E. Brandt、Joel S. Southern、Arnold L. Rheingold、Ilia Guzei、Kraig A. Wheeler、Lew W. Cary
DOI:10.1016/j.ica.2010.08.039
日期:2010.12
activation for 1Cr ⇌ 2Cr and 1W ⇌ 2W are 119.0 and 92.6 kJ mol −1 , respectively, and entropies of activation are 1.4 and −28.2 J K −1 mol −1 , respectively. Isomerization is 10 4 times faster for these complexes than for (OC) 5 M[κ 1 -PPh 2 CH 2 CH 2 P( p -tolyl) 2 ]. A novel mechanism is proposed to account for the rate differences. The X-ray crystal structure of 2W shows that the phosphorus atom of the
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
作者:John William Benson、Richard L. Keiter、Ellen A. Keiter、Arnold L. Rheingold、Glenn P. A. Yap、Vera V. Mainz
DOI:10.1021/om980288p
日期:1998.9.1
Tungsten pentacarbonyl complexes, (OC)5W(η1-PPh2CH2PPh2) (1) and (OC)5W(μ-PPh2CH2PPh2)W(CO)5 (2), have been synthesized from (OC)5WNH2Ph and Ph2PCH2PPh2 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 1 is oriented toward the W(CO)5 unit in the solid state, and 13C1H} and 31P1H} NMR data