Jump to main content
Jump to site search

Issue 9, 2009
Previous Article Next Article

Phosphinimide complexes with pendant hemilabile donors: synthesis, structure and ethylenepolymerization activity

Author affiliations

Abstract

The phosphines tBu2P(CH2)3ECH2Ph (E = O (1), S (2)) converted to the corresponding phosphinimines (Me3SiN)PtBu2(CH2)3ECH2Ph, E = O (3), S (4)) which were used to prepared the titanium complexes Cp′TiCl2NPtBu2(CH2)3ECH2Ph, (E = O, Cp′ = Cp (5), Cp* (6); E = S, Cp′ = Cp (7), Cp* (8)). These species were subsequently methylated to the corresponding dimethyl-derivatives (9)–(12). Activation of (9)–(12) with both B(C6F5)3 and [Ph3C][B(C6F5)4] was studied. For example, the [CpTiMe(NPtBu2(CH2)3OCH2Ph)][MeB(C6F5)3] (13) reacted with THF to give [CpTiMe(THF)(NPtBu2(CH2)3OCH2Ph)][MeB(C6F5)3] (14). Similar reactions gave the stable ion pairs [Cp′TiMe(NPtBu2(CH2)3XCH2Ph)][MeB(C6F5)3] (X = O, Cp′ = Cp*, (15); X = S Cp′ = Cp, (16), Cp*(17)) and [Cp′TiMe(NPtBu2(CH2)3XCH2Ph)][B(C6F5)4] (X = O, Cp′ = Cp, (18); Cp*(19); X = S, Cp′ = Cp, (20), Cp* (21)). The dihalide complexes (5)–(8), activated with MAO, proved to be ethylene polymerization catalysts of moderate activities. The dialkyl titanium complexes (9)–(12) activated with B(C6F5)3 or [Ph3C][B(C6F5)4], gave catalysts that exhibited substantially higher activity and high molecular weight polyethylene. Polymerization at 60 °C rather than 30 °C significantly increased activity as well. The impact of the hemilabile donor with respect to catalyst activity is discussed. Crystallographic studies of (5) and (6) are reported.

Graphical abstract: Phosphinimide complexes with pendant hemilabile donors: synthesis, structure and ethylene polymerization activity

Back to tab navigation

Supplementary files

Article information


Submitted
13 Oct 2008
Accepted
25 Nov 2008
First published
23 Jan 2009

Dalton Trans., 2009, 1636-1643
Article type
Paper

Phosphinimide complexes with pendant hemilabile donors: synthesis, structure and ethylene polymerization activity

K. Yadav, J. S. J. McCahill, G. Bai and D. W. Stephan, Dalton Trans., 2009, 1636
DOI: 10.1039/B817959J

Social activity

Search articles by author

Spotlight

Advertisements