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Ethylene Oligomerization with Cr-NHC Catalysts: Further Insights into the Extended Metallacycle Mechanism of Chain Growth

Citation

McGuinness, DS and Suttil, JA and Gardiner, MG and Davies, NW, Ethylene Oligomerization with Cr-NHC Catalysts: Further Insights into the Extended Metallacycle Mechanism of Chain Growth, Organometallics, 27, (16) pp. 4238-4247. ISSN 0276-7333 (2008) [Refereed Article]

DOI: doi:10.1021/om800398e

Abstract

The mechanism of ethylene oligomerization with chromium(III) complexes of bis(carbene)pyridine ligands in combination with MAO has been investigated. Oligomerization with mixtures of CH2CH2/ CD 2CD2 reveals that this system produces α-olefins via an extended metallacycle mechanism. Deviation form a Schulz-Flory distribution has been explained on the basis of less favorable product release at the early stages of metallacycle growth (Cr-C4 (±Cr-C6)). Significant amounts of branched olefins (methylidenes) and linear internal olefins are produced at the high catalyst loadings employed in this study, and these result from secondary incorporation of α-olefins into the metallacycle mechanism. Changing the ligand C∧N∧C coordination mode in any way resulted in a sharp loss of activity. In the case of bidentate carbene-pyridine and carbene-thiophene ligands, this is due to a change in the mechanism from metallacycle to linear chain growth. Thus, only those catalysts which support a metallacycle mechanism promote oligomerization with high activity. © 2008 American Chemical Society.

Item Details

Item Type:Refereed Article
Research Division:Chemical Sciences
Research Group:Inorganic Chemistry
Research Field:Transition Metal Chemistry
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Chemical Sciences
UTAS Author:McGuinness, DS (Dr David McGuinness)
UTAS Author:Suttil, JA (Mr James Suttil)
UTAS Author:Gardiner, MG (Associate Professor Michael Gardiner)
UTAS Author:Davies, NW (Associate Professor Noel Davies)
ID Code:52363
Year Published:2008
Web of Science® Times Cited:108
Deposited By:Chemistry
Deposited On:2008-06-30
Last Modified:2009-05-01
Downloads:0

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