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.

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