Abstract
The binuclear "constrained geometry catalyst" (CGC) (μ-CH2CH2-3,3′) {(η5-indenyl)[1-Me2Si- (tBuN)](ZrMe2}2 [EBICGC(ZrMe2)2; Zr2] and the trityl bisborate dianion (Ph3C+)2 [1,4-(C6F5) 3BC6F4B (C6F5)3]2- (B2) have been synthesized to serve as new types of multicenter homogeneous olefin polymerization catalysts and cocatalysts, respectively. Additionally, the complex [1-Me2Si(3-ethylindenyl)(tBuN)]ZrMe2 (Zr1) was synthesized as a mononuclear control. For the bimetallic catalyst or bisborate cocatalyst, high effective local active site concentrations and catalyst center-catalyst center cooperative effects are evidenced by bringing the catalytic centers together via either covalent or electrostatic bonding. For ethylene homopolymerization at constant conversion, the branch content of the polyolefin products (primarily ethyl branches) is dramatically increased as catalyst or cocatalyst nuclearity is increased. Moreover, catalyst and cocatalyst nuclearity effects are approximately additive. Compared to the catalyst derived from monometallic Zrl and monofunctional Ph3C+B (C6F5)4 - (B1), the active catalyst derived from bimetallic Zr2 and bifunctional B2 produces ∼11 times more ethyl branches in ethylene homopolymerization via a process which is predominantly intradimer in character. Moreover, ∼3 times more 1-hexene incorporation in ethylene + 1-hexene copolymerization and ∼4 times more 1-pentene incorporation in ethylene + 1-pentene copolymerization are observed for Zr2 + B2 versus Zr1 + B1.
| Original language | English |
|---|---|
| Pages (from-to) | 12725-12741 |
| Number of pages | 17 |
| Journal | Journal of the American Chemical Society |
| Volume | 124 |
| Issue number | 43 |
| DOIs | |
| Publication status | Published - Oct 30 2002 |
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ASJC Scopus subject areas
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Catalyst/cocatalyst nuclearity effects in single-site polymerization. Enhanced polyethylene branching and α-olefin comonomer enchainment in polymerizations mediated by binuclear catalysts and cocatalysts via a new enchainment pathway. / Li, Liting; Metz, Matthew V.; Li, Hongbo; Chen, Ming Chou; Marks, Tobin J; Liable-Sands, Louise; Rheingold, Arnold L.
In: Journal of the American Chemical Society, Vol. 124, No. 43, 30.10.2002, p. 12725-12741.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Catalyst/cocatalyst nuclearity effects in single-site polymerization. Enhanced polyethylene branching and α-olefin comonomer enchainment in polymerizations mediated by binuclear catalysts and cocatalysts via a new enchainment pathway
AU - Li, Liting
AU - Metz, Matthew V.
AU - Li, Hongbo
AU - Chen, Ming Chou
AU - Marks, Tobin J
AU - Liable-Sands, Louise
AU - Rheingold, Arnold L.
PY - 2002/10/30
Y1 - 2002/10/30
N2 - The binuclear "constrained geometry catalyst" (CGC) (μ-CH2CH2-3,3′) {(η5-indenyl)[1-Me2Si- (tBuN)](ZrMe2}2 [EBICGC(ZrMe2)2; Zr2] and the trityl bisborate dianion (Ph3C+)2 [1,4-(C6F5) 3BC6F4B (C6F5)3]2- (B2) have been synthesized to serve as new types of multicenter homogeneous olefin polymerization catalysts and cocatalysts, respectively. Additionally, the complex [1-Me2Si(3-ethylindenyl)(tBuN)]ZrMe2 (Zr1) was synthesized as a mononuclear control. For the bimetallic catalyst or bisborate cocatalyst, high effective local active site concentrations and catalyst center-catalyst center cooperative effects are evidenced by bringing the catalytic centers together via either covalent or electrostatic bonding. For ethylene homopolymerization at constant conversion, the branch content of the polyolefin products (primarily ethyl branches) is dramatically increased as catalyst or cocatalyst nuclearity is increased. Moreover, catalyst and cocatalyst nuclearity effects are approximately additive. Compared to the catalyst derived from monometallic Zrl and monofunctional Ph3C+B (C6F5)4 - (B1), the active catalyst derived from bimetallic Zr2 and bifunctional B2 produces ∼11 times more ethyl branches in ethylene homopolymerization via a process which is predominantly intradimer in character. Moreover, ∼3 times more 1-hexene incorporation in ethylene + 1-hexene copolymerization and ∼4 times more 1-pentene incorporation in ethylene + 1-pentene copolymerization are observed for Zr2 + B2 versus Zr1 + B1.
AB - The binuclear "constrained geometry catalyst" (CGC) (μ-CH2CH2-3,3′) {(η5-indenyl)[1-Me2Si- (tBuN)](ZrMe2}2 [EBICGC(ZrMe2)2; Zr2] and the trityl bisborate dianion (Ph3C+)2 [1,4-(C6F5) 3BC6F4B (C6F5)3]2- (B2) have been synthesized to serve as new types of multicenter homogeneous olefin polymerization catalysts and cocatalysts, respectively. Additionally, the complex [1-Me2Si(3-ethylindenyl)(tBuN)]ZrMe2 (Zr1) was synthesized as a mononuclear control. For the bimetallic catalyst or bisborate cocatalyst, high effective local active site concentrations and catalyst center-catalyst center cooperative effects are evidenced by bringing the catalytic centers together via either covalent or electrostatic bonding. For ethylene homopolymerization at constant conversion, the branch content of the polyolefin products (primarily ethyl branches) is dramatically increased as catalyst or cocatalyst nuclearity is increased. Moreover, catalyst and cocatalyst nuclearity effects are approximately additive. Compared to the catalyst derived from monometallic Zrl and monofunctional Ph3C+B (C6F5)4 - (B1), the active catalyst derived from bimetallic Zr2 and bifunctional B2 produces ∼11 times more ethyl branches in ethylene homopolymerization via a process which is predominantly intradimer in character. Moreover, ∼3 times more 1-hexene incorporation in ethylene + 1-hexene copolymerization and ∼4 times more 1-pentene incorporation in ethylene + 1-pentene copolymerization are observed for Zr2 + B2 versus Zr1 + B1.
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U2 - 10.1021/ja0201698
DO - 10.1021/ja0201698
M3 - Article
VL - 124
SP - 12725
EP - 12741
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 43
ER -