Chemisorption pathways and catalytic olefin polymerization properties of group 4 mono- and binuclear constrained geometry complexes on highly acidic sulfated alumina

Linda A. Williams, Tobin J Marks

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23 Citations (Scopus)

Abstract

Mono- and binuclear "constrained-geometry catalyst" (CGC) group 4 hydrocarbyls Me 2Si(Me 5C 5)-( tBuN)ZrMe 2 [CGCZrMe 2,1], 1-Me 2Si(3-ethylindenyl)( tBuN)ZrMe 2 [EICGCZrMe 2; Zr 1, 2], (μ-CH 2CH 2-3,3) {(η 5-indenyl)[1-Me 2Si-( tBuN)](ZrMe 2)} 2 [EBICGC(ZrMe 2) 2, Zr 2, 3], and (μ-CH 2CH 2-3,3){η 5- indenyl)[1-Me 2Si-( tBuN)](TiMe 2)} 2 [EBICGC(TiMe 2) 2, Ti 2, 4] undergo rapid chemisorption on highly Brønsted acidic sulfated alumina (A1S) surfaces. 13C CPMAS NMR spectroscopy of the chemisorbed 13C aH 3-enriched complexes EICGCZr 13Me 2/AlS (2*/AlS) and EBICGC(Zr 13Me 2) 2/AlS (3*/AlS) reveals that chemisorption involves two processes, M-C σ-bond protonolysis at the strong surface Brønsted acid sites and heterolytic M-C scission with methide transfer to strong surface Lewis acid sites, forming similar "cation-like" electrophilic organo-group 4 complexes such as EICGCM 13Me +. Relative rates of ethylene homopolymerization mediated by the catalysts prepared via chemisorption on A1S are 4/A1S > 2/A1S > 3/A1S > 1/A1S, for ethylene polymerization at 75 psi ethylene and 25 °C. Ethylene/1-hexene eopolymerizations mediated by the same set of catalysts display relative polymerization rates of 4/A1S > 3/A1S > 2/A1S > 1/A1S, for copolymerizations at 75 psi ethylene, 0.8 M 1-hexene, and 25 °C.

Original languageEnglish
Pages (from-to)2053-2061
Number of pages9
JournalOrganometallics
Volume28
Issue number7
DOIs
Publication statusPublished - Apr 13 2009

Fingerprint

Aluminum Oxide
Alkenes
Chemisorption
chemisorption
alkenes
ethylene
polymerization
aluminum oxides
Polymerization
Geometry
geometry
hexenes
catalysts
Catalysts
methylidyne
Lewis Acids
acids
copolymerization
Homopolymerization
Copolymerization

ASJC Scopus subject areas

  • Organic Chemistry
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Cite this

@article{7366bbc7486e4530b2db15a51d8163d6,
title = "Chemisorption pathways and catalytic olefin polymerization properties of group 4 mono- and binuclear constrained geometry complexes on highly acidic sulfated alumina",
abstract = "Mono- and binuclear {"}constrained-geometry catalyst{"} (CGC) group 4 hydrocarbyls Me 2Si(Me 5C 5)-( tBuN)ZrMe 2 [CGCZrMe 2,1], 1-Me 2Si(3-ethylindenyl)( tBuN)ZrMe 2 [EICGCZrMe 2; Zr 1, 2], (μ-CH 2CH 2-3,3) {(η 5-indenyl)[1-Me 2Si-( tBuN)](ZrMe 2)} 2 [EBICGC(ZrMe 2) 2, Zr 2, 3], and (μ-CH 2CH 2-3,3){η 5- indenyl)[1-Me 2Si-( tBuN)](TiMe 2)} 2 [EBICGC(TiMe 2) 2, Ti 2, 4] undergo rapid chemisorption on highly Br{\o}nsted acidic sulfated alumina (A1S) surfaces. 13C CPMAS NMR spectroscopy of the chemisorbed 13C aH 3-enriched complexes EICGCZr 13Me 2/AlS (2*/AlS) and EBICGC(Zr 13Me 2) 2/AlS (3*/AlS) reveals that chemisorption involves two processes, M-C σ-bond protonolysis at the strong surface Br{\o}nsted acid sites and heterolytic M-C scission with methide transfer to strong surface Lewis acid sites, forming similar {"}cation-like{"} electrophilic organo-group 4 complexes such as EICGCM 13Me +. Relative rates of ethylene homopolymerization mediated by the catalysts prepared via chemisorption on A1S are 4/A1S > 2/A1S > 3/A1S > 1/A1S, for ethylene polymerization at 75 psi ethylene and 25 °C. Ethylene/1-hexene eopolymerizations mediated by the same set of catalysts display relative polymerization rates of 4/A1S > 3/A1S > 2/A1S > 1/A1S, for copolymerizations at 75 psi ethylene, 0.8 M 1-hexene, and 25 °C.",
author = "Williams, {Linda A.} and Marks, {Tobin J}",
year = "2009",
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TY - JOUR

T1 - Chemisorption pathways and catalytic olefin polymerization properties of group 4 mono- and binuclear constrained geometry complexes on highly acidic sulfated alumina

AU - Williams, Linda A.

AU - Marks, Tobin J

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N2 - Mono- and binuclear "constrained-geometry catalyst" (CGC) group 4 hydrocarbyls Me 2Si(Me 5C 5)-( tBuN)ZrMe 2 [CGCZrMe 2,1], 1-Me 2Si(3-ethylindenyl)( tBuN)ZrMe 2 [EICGCZrMe 2; Zr 1, 2], (μ-CH 2CH 2-3,3) {(η 5-indenyl)[1-Me 2Si-( tBuN)](ZrMe 2)} 2 [EBICGC(ZrMe 2) 2, Zr 2, 3], and (μ-CH 2CH 2-3,3){η 5- indenyl)[1-Me 2Si-( tBuN)](TiMe 2)} 2 [EBICGC(TiMe 2) 2, Ti 2, 4] undergo rapid chemisorption on highly Brønsted acidic sulfated alumina (A1S) surfaces. 13C CPMAS NMR spectroscopy of the chemisorbed 13C aH 3-enriched complexes EICGCZr 13Me 2/AlS (2*/AlS) and EBICGC(Zr 13Me 2) 2/AlS (3*/AlS) reveals that chemisorption involves two processes, M-C σ-bond protonolysis at the strong surface Brønsted acid sites and heterolytic M-C scission with methide transfer to strong surface Lewis acid sites, forming similar "cation-like" electrophilic organo-group 4 complexes such as EICGCM 13Me +. Relative rates of ethylene homopolymerization mediated by the catalysts prepared via chemisorption on A1S are 4/A1S > 2/A1S > 3/A1S > 1/A1S, for ethylene polymerization at 75 psi ethylene and 25 °C. Ethylene/1-hexene eopolymerizations mediated by the same set of catalysts display relative polymerization rates of 4/A1S > 3/A1S > 2/A1S > 1/A1S, for copolymerizations at 75 psi ethylene, 0.8 M 1-hexene, and 25 °C.

AB - Mono- and binuclear "constrained-geometry catalyst" (CGC) group 4 hydrocarbyls Me 2Si(Me 5C 5)-( tBuN)ZrMe 2 [CGCZrMe 2,1], 1-Me 2Si(3-ethylindenyl)( tBuN)ZrMe 2 [EICGCZrMe 2; Zr 1, 2], (μ-CH 2CH 2-3,3) {(η 5-indenyl)[1-Me 2Si-( tBuN)](ZrMe 2)} 2 [EBICGC(ZrMe 2) 2, Zr 2, 3], and (μ-CH 2CH 2-3,3){η 5- indenyl)[1-Me 2Si-( tBuN)](TiMe 2)} 2 [EBICGC(TiMe 2) 2, Ti 2, 4] undergo rapid chemisorption on highly Brønsted acidic sulfated alumina (A1S) surfaces. 13C CPMAS NMR spectroscopy of the chemisorbed 13C aH 3-enriched complexes EICGCZr 13Me 2/AlS (2*/AlS) and EBICGC(Zr 13Me 2) 2/AlS (3*/AlS) reveals that chemisorption involves two processes, M-C σ-bond protonolysis at the strong surface Brønsted acid sites and heterolytic M-C scission with methide transfer to strong surface Lewis acid sites, forming similar "cation-like" electrophilic organo-group 4 complexes such as EICGCM 13Me +. Relative rates of ethylene homopolymerization mediated by the catalysts prepared via chemisorption on A1S are 4/A1S > 2/A1S > 3/A1S > 1/A1S, for ethylene polymerization at 75 psi ethylene and 25 °C. Ethylene/1-hexene eopolymerizations mediated by the same set of catalysts display relative polymerization rates of 4/A1S > 3/A1S > 2/A1S > 1/A1S, for copolymerizations at 75 psi ethylene, 0.8 M 1-hexene, and 25 °C.

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