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Vanadium-based imido-alkoxide pro-catalysts bearing bisphenolate ligands for ethylene and ε-caprolactone polymerisation

Arbaoui, Abdessamad; Redshaw, Carl; Homden, Damien M.; Wright, Joseph A.; Elsegood, Mark R.J.

Authors

Abdessamad Arbaoui

Damien M. Homden

Joseph A. Wright

Mark R.J. Elsegood



Abstract

The pro-catalysts [V(NAr)(L)(OR)] (Ar = p-tolyl, p-ClC6H 4, p-(OMe)C6H4, p-(CF3)C 6H4; R = t-Bu, i-Pr, n-Pr, Et, C(CH3)(CF 3)2) have been prepared in good yields from the reaction of [V(NAr)(OR)3] and the bisphenol 2,2′-CH3CH[4,6- (t-Bu)2C6H2OH]2 (LH2). X-Ray crystal structure determinations for the Ar = p-tolyl, R = t-Bu (1), R = C(CH3)(CF3)2 (2) and Ar = p-ClC 6H4, R = t-Bu (3) derivatives revealed monomeric complexes, whereas use of R = i-Pr, n-Pr or Et led to alkoxide-bridged dimeric structures of the form [V(NAr)(L)(μ-OR)]2 (R = i-Pr, Ar = p-tolyl (4), p-ClC6H4 (5), p-(CF3)C6H 4 (6), p-(OMe)C6H4 (7); R = n-Pr, Ar = p-tolyl (8), p-(CF3)C6H4 (9); R = Et, Ar = p-ClC 6H4 (10), p-tolyl (11)). Complexes 1-11 yield highly active ethylene polymerisation catalysts when treated with DMAC (dimethylaluminium chloride) in the presence of ETA (ethyltrichloroacetate), with activities in the range 38800 to 75200 g mmol-1 h-1 bar-1. The molecular weights of the resultant polymers were in the range 37000 to 411000 g mol-1, with molecular weight distribution 2.2 to 4.7. The effect of the nature of the para-arylimido substituent and the alkoxide group OR upon the catalytic activity has been investigated. For ε-caprolactone polymerisation, mononuclear 1-3 exhibit low conversion (≤25%; 0% for 2), whereas use of the dimeric species 4-11 led to higher conversions (41-78%). © 2009 The Royal Society of Chemistry.

Citation

Arbaoui, A., Redshaw, C., Homden, D. M., Wright, J. A., & Elsegood, M. R. (2009). Vanadium-based imido-alkoxide pro-catalysts bearing bisphenolate ligands for ethylene and ε-caprolactone polymerisation. Dalton Transactions : an international journal of inorganic chemistry, 8911-8922. https://doi.org/10.1039/b902402f

Journal Article Type Article
Acceptance Date May 15, 2009
Online Publication Date Jul 7, 2009
Publication Date Oct 19, 2009
Deposit Date Jun 8, 2022
Journal Dalton Transactions
Print ISSN 1477-9226
Electronic ISSN 1477-9234
Publisher Royal Society of Chemistry
Peer Reviewed Peer Reviewed
Issue 41
Pages 8911-8922
DOI https://doi.org/10.1039/b902402f
Public URL https://hull-repository.worktribe.com/output/3622524