Coordination copolymerization of severely encumbered isoalkenes with ethylene: Enhanced enchainment mediated by binuclear catalysts and cocatalysts

Hongbo Li, Liting Li, David J. Schwartz, Matthew V. Metz, Tobin J Marks, Louise Liable-Sands, Arnold L. Rheingold

Research output: Contribution to journalArticle

79 Citations (Scopus)

Abstract

This contribution describes the implementation of the binuclear organotitanium "constrained geometry catalysts" (CGCs), (μ-CH 2CH2-3,3′){(η5-indenyl)[1-Me 2Si(tBuN)](TiMe2)}2[EBICGC(TiMe 2)2; Ti2] and (μ-CH2-3,3′) {(η5-indenyl)[1-Me2Si(tBuN)](TiMe 2)}2[MBICGC(TiMe2)2; C1-Ti 2], in combination with the bifunctional bisborane activator 1,4-(C6F5)2BC6F4B(C 6F5)2 (BN2) in ethylene + olefin copolymerization processes. Specifically examined are the classically poorly responsive 1,1-disubstituted comonomers, methylenecyclopentane (C), methylenecyclohexane (D), 1,1,2-trisubstituted 2-methyl-2-butene (E), and isobutene (F). For the first three comonomers, this represents the first report of their incorporation into a polyethylene backbone via a coordination polymerization process. C and D are incorporated via a ring-unopened pathway, and E is incorporated via a novel pathway involving 2-methyl-1 -butene enchainment in the copolymer backbone. In ethylene copolymerization, Ti 2 + BN2 enchains ∼2.5 times more C, ∼2.5 times more D, and ∼2.3 times more E than the mononuclear catalyst analogue [1-Me2Si(3-ethylindenyl)-(tBuN)]TiMe2 (Ti 1) + B(C6F5)3 (BN) under identical polymerization conditions. Polar solvents are found to weaken the catalyst-cocatalyst ion pairing, thus influencing the comonomer enchainment selectivity.

Original languageEnglish
Pages (from-to)14756-14768
Number of pages13
JournalJournal of the American Chemical Society
Volume127
Issue number42
DOIs
Publication statusPublished - Nov 1 2005

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Polymerization
Copolymerization
Ethylene
Butenes
Catalysts
Alkenes
Polyethylene
Ions
Olefins
Polyethylenes
Copolymers
Geometry
ethylene
2-butene
isobutylene
1-butene

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Coordination copolymerization of severely encumbered isoalkenes with ethylene : Enhanced enchainment mediated by binuclear catalysts and cocatalysts. / Li, Hongbo; Li, Liting; Schwartz, David J.; Metz, Matthew V.; Marks, Tobin J; Liable-Sands, Louise; Rheingold, Arnold L.

In: Journal of the American Chemical Society, Vol. 127, No. 42, 01.11.2005, p. 14756-14768.

Research output: Contribution to journalArticle

Li, Hongbo ; Li, Liting ; Schwartz, David J. ; Metz, Matthew V. ; Marks, Tobin J ; Liable-Sands, Louise ; Rheingold, Arnold L. / Coordination copolymerization of severely encumbered isoalkenes with ethylene : Enhanced enchainment mediated by binuclear catalysts and cocatalysts. In: Journal of the American Chemical Society. 2005 ; Vol. 127, No. 42. pp. 14756-14768.
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AU - Schwartz, David J.

AU - Metz, Matthew V.

AU - Marks, Tobin J

AU - Liable-Sands, Louise

AU - Rheingold, Arnold L.

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