Abstract
This communication reports the styrene homopolymerization behavior and ethylene-styrene copolymerization behavior of the covalently linked bimetallic constrained geometry catalyst (μ-CH2CH2-3,3′){(η5-indenyl)[1-Me2Si(tBuN)](TiMe2)}2 (Ti2), which is the first single-site catalyst that effects not only styrene homopolymerization with high activity, but also efficient ethylene-styrene copolymerization over a broad styrene composition range (0-76% at 20 °C, 1.0 atm ethylene pressure). In styrene homopolymerization, a 50× increase in polymerization activity is achieved with Ti2 vs the mononuclear analogue, Ti1, using an identical trityl borate cocatalyst and polymerization conditions. In ethylene + styrene copolymerization, Ti2 enchains ∼20% more styrene than Ti1 under identical reaction conditions. 13C NMR spectroscopy indicates that greater than two consecutive styrene units are enchained in the copolymer backbone produced by Ti2 + Ph3C+B(C6F5)4-. End group analysis of the styrene homopolymer produced by Ti2 + Ph3C+B(C6F5)4- suggests that 1,2-regiochemistry is installed in ∼50% of the initiation steps. This unusual microstructure is believed to be related to the bimetallic catalyst structure.
| Original language | English |
|---|---|
| Pages (from-to) | 6542-6543 |
| Number of pages | 2 |
| Journal | Journal of the American Chemical Society |
| Volume | 126 |
| Issue number | 21 |
| DOIs | |
| Publication status | Published - Jun 2 2004 |
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ASJC Scopus subject areas
- Chemistry(all)
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Bimetallic catalysis for styrene homopolymerization and ethylene-styrene copolymerization. Exceptional comonomer selectivity and insertion regiochemistry. / Guo, Neng; Li, Liting; Marks, Tobin J.
In: Journal of the American Chemical Society, Vol. 126, No. 21, 02.06.2004, p. 6542-6543.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Bimetallic catalysis for styrene homopolymerization and ethylene-styrene copolymerization. Exceptional comonomer selectivity and insertion regiochemistry
AU - Guo, Neng
AU - Li, Liting
AU - Marks, Tobin J
PY - 2004/6/2
Y1 - 2004/6/2
N2 - This communication reports the styrene homopolymerization behavior and ethylene-styrene copolymerization behavior of the covalently linked bimetallic constrained geometry catalyst (μ-CH2CH2-3,3′){(η5-indenyl)[1-Me2Si(tBuN)](TiMe2)}2 (Ti2), which is the first single-site catalyst that effects not only styrene homopolymerization with high activity, but also efficient ethylene-styrene copolymerization over a broad styrene composition range (0-76% at 20 °C, 1.0 atm ethylene pressure). In styrene homopolymerization, a 50× increase in polymerization activity is achieved with Ti2 vs the mononuclear analogue, Ti1, using an identical trityl borate cocatalyst and polymerization conditions. In ethylene + styrene copolymerization, Ti2 enchains ∼20% more styrene than Ti1 under identical reaction conditions. 13C NMR spectroscopy indicates that greater than two consecutive styrene units are enchained in the copolymer backbone produced by Ti2 + Ph3C+B(C6F5)4-. End group analysis of the styrene homopolymer produced by Ti2 + Ph3C+B(C6F5)4- suggests that 1,2-regiochemistry is installed in ∼50% of the initiation steps. This unusual microstructure is believed to be related to the bimetallic catalyst structure.
AB - This communication reports the styrene homopolymerization behavior and ethylene-styrene copolymerization behavior of the covalently linked bimetallic constrained geometry catalyst (μ-CH2CH2-3,3′){(η5-indenyl)[1-Me2Si(tBuN)](TiMe2)}2 (Ti2), which is the first single-site catalyst that effects not only styrene homopolymerization with high activity, but also efficient ethylene-styrene copolymerization over a broad styrene composition range (0-76% at 20 °C, 1.0 atm ethylene pressure). In styrene homopolymerization, a 50× increase in polymerization activity is achieved with Ti2 vs the mononuclear analogue, Ti1, using an identical trityl borate cocatalyst and polymerization conditions. In ethylene + styrene copolymerization, Ti2 enchains ∼20% more styrene than Ti1 under identical reaction conditions. 13C NMR spectroscopy indicates that greater than two consecutive styrene units are enchained in the copolymer backbone produced by Ti2 + Ph3C+B(C6F5)4-. End group analysis of the styrene homopolymer produced by Ti2 + Ph3C+B(C6F5)4- suggests that 1,2-regiochemistry is installed in ∼50% of the initiation steps. This unusual microstructure is believed to be related to the bimetallic catalyst structure.
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U2 - 10.1021/ja048761f
DO - 10.1021/ja048761f
M3 - Article
VL - 126
SP - 6542
EP - 6543
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 21
ER -