The mechanism of ethylene trimerisation and tetramerisation with chromium–diphosphinoamine (Cr–PNP) catalysts has been studied by experimental and theoretical (DFT) methods. The effects of a pendant ether donor (ortho-methoxyaryl ligand substitution) and of anion coordination to the active species have been studied. In the former case, coordination of the ether donor to chromium favours 1-hexene by suppressing formation of the bis(ethylene) chromacyclopentane intermediate which is postulated to be the major route to 1-octene. The effect of anion coordination is similar and as the coordination strength increases, displacement of the anion by a second ethylene ligand becomes more difficult, again favouring trimerisation over tetramerisation. Hence, the experimentally observed effects of pendant donor coordination and changes in anion coordination strength can be rationalised.

Item Type:	Refereed Article
Keywords:	trimerisation, tetramerisation, DFT
Research Division:	Chemical Sciences
Research Group:	Other Chemical Sciences
Research Field:	Organometallic Chemistry
Objective Division:	Manufacturing
Objective Group:	Industrial Chemicals and Related Products
Objective Field:	Organic Industrial Chemicals (excl. Resins, Rubber and Plastics)
Author:	McGuinness, DS (Dr David McGuinness)
ID Code:	113508
Year Published:	2016
Funding Support:	Australian Research Council (FT100100609)
Web of Science® Times Cited:	2
Deposited By:	Chemistry
Deposited On:	2017-01-05
Last Modified:	2017-03-01
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