Thermal Decomposition Modes for Four‐Coordinate Ruthenium Phosphonium Alkylidene Olefin Metathesis Catalysts |
| |
Authors: | Erin M Leitao Stuart R Dubberley Dr Warren E Piers Prof Qiao Wu Dr Robert McDonald Dr |
| |
Institution: | 1. Department of Chemistry, University of Calgary, 2500 University Dr. N.W., Calgary, AB, T2N 1N4 (Canada), Fax: (+1)?403‐289‐9488;2. Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, AB, T6G 2G2 (Canada) |
| |
Abstract: | The four‐coordinate ruthenium phosphonium alkylidenes 1‐Cy and 1‐iPr , differing in the substituent on the phosphorus center, were observed to decompose thermally in the presence of 1,1‐dichloroethylene to produce H3CPR3]Cl]. The major ruthenium‐containing product was a trichloro‐bridged ruthenium dimer that incorporates the elements of the 1,1‐dichloroethylene as a dichlorocarbene ligand and a styrenic vinyl group on the supporting NHC ligand. Spectroscopic, kinetic, and deuterium‐labeling experiments probed the mechanism of this process, which involves a rate‐limiting C–H activation of an NHC mesityl ortho methyl group. These studies provide insight into intrinsic decomposition processes of active Grubbs type olefin metathesis catalysts, pointing the way to new catalyst design directions. |
| |
Keywords: | catalysis decomposition kinetics olefin metathesis ruthenium |
|
|