New organo-lewis acids. Tris(β-perfluoronaphthyl)borane (PNB) as a highly active cocatalyst for metallocene-mediated ziegler-natta α-olefin polymerization

Liting Li, Tobin J Marks

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116 Citations (Scopus)

Abstract

Tris(β-perfluoronaphthyl)borane (B(C10F7)3, PNB) is synthesized from β-perfluoronaphthyllithium and BCl3 to serve as a new strong organo-Lewis acid cocatalyst. PNB efficiently activates a variety of group 4 dimethyl complexes to form highly active homogeneous Ziegler-Natta olefin polymerization catalysts. Reaction of PNB with rac-Me2Si(Ind)2ZrMe2 and CGCMMe2 (M = Zr, Ti; CGC = Me2Si(η5-Me4C5)( tBuN)) (1:1 molar ratio) rapidly produces the base-free cationic complexes rac-Me2Si(Ind)2ZrMe+MePNB- (1) and CGCMMe+MePNB- (M = Zr, 2; Ti, 3), respectively. The μ-methyl dinuclear cationic complex [(CGCTiMe)2(μ-Me)]+MePNB- (4) is formed when a 2:1 CGCTiMe2:PNB stoichiometry is employed: In the case of group 4 dimethyl zirconocenes, L2ZrMe2 (L = η5-C5H5, Cp; η5-1,2-Me2C5H3, Cp″), reaction in a 1:1 metallocene:PNB ratio affords cationic complexes L2ZrMe+MePNB- (L = Cp, 5; Cp″, 6), while the reaction with a 1:2 molar ratio affords dinuclear μ-methyl cationic complexes [(L2ZrMe)2(μ-Me)]+MePNB- (L = Cp, 7; Cp″, 8). In both reactions, μ-F dinuclear cationic complexes [(L2ZrMe)2(M-F)]+MePNB- (L = Cp, 9; Cp″, 10) are formed as byproducts. (C6F5)3BNCCH3 and PNBNCCH3 were synthesized and characterized. Analysis of the PNBNCCH3 + B(C6F5)3 ⇄ (C6F5)3BNCCH3 + PNB equilibrium yields ΔH° = +0.7(2) kcal/ mol and ΔS° = +4.3(5) eu, suggesting PNB has somewhat higher Lewis acidity and is sterically more encumbered than B(C6F5)3. Solution ν(CN) values for PNBNCCH3 and (C6F5)3-BNCCH3 are 2365.3 and 2366.5 cm-1, respectively, which indicate strong Lewis acidity. PBBNCCH3 cannot be detected in the reaction of (C6F5)3BNCCH3 with PBB [PBB = tris-(2,2′,2″-perfluorobipheny)lborane] over prolonged periods at 60°C. In ethylene polymerization, PNB-derived cationic complexes 5, 6, 7, and 8 have catalytic activities similar to the B(C6F5)3-derived analogues, while 2 and 3 have substantially higher activities. In propylene polymerization, catalyst 1 has higher activity than the B(C6F5)3 analogue. In the case of ethylene and 1-hexene copolymerization, PNB-derived cationic complex 3 exhibits higher polymerization activity with similar 1-hexene incorporation versus the B(C6F5)3-derived cationic complex. In large-scale batch copolymerizations of ethylene and 1-octene mediated by CGCTiMe2, the PNB-based catalytic systems exhibit approximately twice the activity of the B(C6F5)3-based systems.

Original languageEnglish
Pages (from-to)3996-4003
Number of pages8
JournalOrganometallics
Volume17
Issue number18
Publication statusPublished - Aug 31 1998

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Boranes
Lewis Acids
boranes
Alkenes
alkenes
polymerization
Polymerization
acids
polybrominated biphenyls
hexenes
ethylene
copolymerization
Acidity
acidity
Copolymerization
metallocene
analogs
catalysts
Catalysts
propylene

ASJC Scopus subject areas

  • Inorganic Chemistry
  • Organic Chemistry

Cite this

@article{e1f98e982d6a436daf0af814c7cc9a30,
title = "New organo-lewis acids. Tris(β-perfluoronaphthyl)borane (PNB) as a highly active cocatalyst for metallocene-mediated ziegler-natta α-olefin polymerization",
abstract = "Tris(β-perfluoronaphthyl)borane (B(C10F7)3, PNB) is synthesized from β-perfluoronaphthyllithium and BCl3 to serve as a new strong organo-Lewis acid cocatalyst. PNB efficiently activates a variety of group 4 dimethyl complexes to form highly active homogeneous Ziegler-Natta olefin polymerization catalysts. Reaction of PNB with rac-Me2Si(Ind)2ZrMe2 and CGCMMe2 (M = Zr, Ti; CGC = Me2Si(η5-Me4C5)( tBuN)) (1:1 molar ratio) rapidly produces the base-free cationic complexes rac-Me2Si(Ind)2ZrMe+MePNB- (1) and CGCMMe+MePNB- (M = Zr, 2; Ti, 3), respectively. The μ-methyl dinuclear cationic complex [(CGCTiMe)2(μ-Me)]+MePNB- (4) is formed when a 2:1 CGCTiMe2:PNB stoichiometry is employed: In the case of group 4 dimethyl zirconocenes, L2ZrMe2 (L = η5-C5H5, Cp; η5-1,2-Me2C5H3, Cp″), reaction in a 1:1 metallocene:PNB ratio affords cationic complexes L2ZrMe+MePNB- (L = Cp, 5; Cp″, 6), while the reaction with a 1:2 molar ratio affords dinuclear μ-methyl cationic complexes [(L2ZrMe)2(μ-Me)]+MePNB- (L = Cp, 7; Cp″, 8). In both reactions, μ-F dinuclear cationic complexes [(L2ZrMe)2(M-F)]+MePNB- (L = Cp, 9; Cp″, 10) are formed as byproducts. (C6F5)3BNCCH3 and PNBNCCH3 were synthesized and characterized. Analysis of the PNBNCCH3 + B(C6F5)3 ⇄ (C6F5)3BNCCH3 + PNB equilibrium yields ΔH° = +0.7(2) kcal/ mol and ΔS° = +4.3(5) eu, suggesting PNB has somewhat higher Lewis acidity and is sterically more encumbered than B(C6F5)3. Solution ν(CN) values for PNBNCCH3 and (C6F5)3-BNCCH3 are 2365.3 and 2366.5 cm-1, respectively, which indicate strong Lewis acidity. PBBNCCH3 cannot be detected in the reaction of (C6F5)3BNCCH3 with PBB [PBB = tris-(2,2′,2″-perfluorobipheny)lborane] over prolonged periods at 60°C. In ethylene polymerization, PNB-derived cationic complexes 5, 6, 7, and 8 have catalytic activities similar to the B(C6F5)3-derived analogues, while 2 and 3 have substantially higher activities. In propylene polymerization, catalyst 1 has higher activity than the B(C6F5)3 analogue. In the case of ethylene and 1-hexene copolymerization, PNB-derived cationic complex 3 exhibits higher polymerization activity with similar 1-hexene incorporation versus the B(C6F5)3-derived cationic complex. In large-scale batch copolymerizations of ethylene and 1-octene mediated by CGCTiMe2, the PNB-based catalytic systems exhibit approximately twice the activity of the B(C6F5)3-based systems.",
author = "Liting Li and Marks, {Tobin J}",
year = "1998",
month = "8",
day = "31",
language = "English",
volume = "17",
pages = "3996--4003",
journal = "Organometallics",
issn = "0276-7333",
publisher = "American Chemical Society",
number = "18",

}

TY - JOUR

T1 - New organo-lewis acids. Tris(β-perfluoronaphthyl)borane (PNB) as a highly active cocatalyst for metallocene-mediated ziegler-natta α-olefin polymerization

AU - Li, Liting

AU - Marks, Tobin J

PY - 1998/8/31

Y1 - 1998/8/31

N2 - Tris(β-perfluoronaphthyl)borane (B(C10F7)3, PNB) is synthesized from β-perfluoronaphthyllithium and BCl3 to serve as a new strong organo-Lewis acid cocatalyst. PNB efficiently activates a variety of group 4 dimethyl complexes to form highly active homogeneous Ziegler-Natta olefin polymerization catalysts. Reaction of PNB with rac-Me2Si(Ind)2ZrMe2 and CGCMMe2 (M = Zr, Ti; CGC = Me2Si(η5-Me4C5)( tBuN)) (1:1 molar ratio) rapidly produces the base-free cationic complexes rac-Me2Si(Ind)2ZrMe+MePNB- (1) and CGCMMe+MePNB- (M = Zr, 2; Ti, 3), respectively. The μ-methyl dinuclear cationic complex [(CGCTiMe)2(μ-Me)]+MePNB- (4) is formed when a 2:1 CGCTiMe2:PNB stoichiometry is employed: In the case of group 4 dimethyl zirconocenes, L2ZrMe2 (L = η5-C5H5, Cp; η5-1,2-Me2C5H3, Cp″), reaction in a 1:1 metallocene:PNB ratio affords cationic complexes L2ZrMe+MePNB- (L = Cp, 5; Cp″, 6), while the reaction with a 1:2 molar ratio affords dinuclear μ-methyl cationic complexes [(L2ZrMe)2(μ-Me)]+MePNB- (L = Cp, 7; Cp″, 8). In both reactions, μ-F dinuclear cationic complexes [(L2ZrMe)2(M-F)]+MePNB- (L = Cp, 9; Cp″, 10) are formed as byproducts. (C6F5)3BNCCH3 and PNBNCCH3 were synthesized and characterized. Analysis of the PNBNCCH3 + B(C6F5)3 ⇄ (C6F5)3BNCCH3 + PNB equilibrium yields ΔH° = +0.7(2) kcal/ mol and ΔS° = +4.3(5) eu, suggesting PNB has somewhat higher Lewis acidity and is sterically more encumbered than B(C6F5)3. Solution ν(CN) values for PNBNCCH3 and (C6F5)3-BNCCH3 are 2365.3 and 2366.5 cm-1, respectively, which indicate strong Lewis acidity. PBBNCCH3 cannot be detected in the reaction of (C6F5)3BNCCH3 with PBB [PBB = tris-(2,2′,2″-perfluorobipheny)lborane] over prolonged periods at 60°C. In ethylene polymerization, PNB-derived cationic complexes 5, 6, 7, and 8 have catalytic activities similar to the B(C6F5)3-derived analogues, while 2 and 3 have substantially higher activities. In propylene polymerization, catalyst 1 has higher activity than the B(C6F5)3 analogue. In the case of ethylene and 1-hexene copolymerization, PNB-derived cationic complex 3 exhibits higher polymerization activity with similar 1-hexene incorporation versus the B(C6F5)3-derived cationic complex. In large-scale batch copolymerizations of ethylene and 1-octene mediated by CGCTiMe2, the PNB-based catalytic systems exhibit approximately twice the activity of the B(C6F5)3-based systems.

AB - Tris(β-perfluoronaphthyl)borane (B(C10F7)3, PNB) is synthesized from β-perfluoronaphthyllithium and BCl3 to serve as a new strong organo-Lewis acid cocatalyst. PNB efficiently activates a variety of group 4 dimethyl complexes to form highly active homogeneous Ziegler-Natta olefin polymerization catalysts. Reaction of PNB with rac-Me2Si(Ind)2ZrMe2 and CGCMMe2 (M = Zr, Ti; CGC = Me2Si(η5-Me4C5)( tBuN)) (1:1 molar ratio) rapidly produces the base-free cationic complexes rac-Me2Si(Ind)2ZrMe+MePNB- (1) and CGCMMe+MePNB- (M = Zr, 2; Ti, 3), respectively. The μ-methyl dinuclear cationic complex [(CGCTiMe)2(μ-Me)]+MePNB- (4) is formed when a 2:1 CGCTiMe2:PNB stoichiometry is employed: In the case of group 4 dimethyl zirconocenes, L2ZrMe2 (L = η5-C5H5, Cp; η5-1,2-Me2C5H3, Cp″), reaction in a 1:1 metallocene:PNB ratio affords cationic complexes L2ZrMe+MePNB- (L = Cp, 5; Cp″, 6), while the reaction with a 1:2 molar ratio affords dinuclear μ-methyl cationic complexes [(L2ZrMe)2(μ-Me)]+MePNB- (L = Cp, 7; Cp″, 8). In both reactions, μ-F dinuclear cationic complexes [(L2ZrMe)2(M-F)]+MePNB- (L = Cp, 9; Cp″, 10) are formed as byproducts. (C6F5)3BNCCH3 and PNBNCCH3 were synthesized and characterized. Analysis of the PNBNCCH3 + B(C6F5)3 ⇄ (C6F5)3BNCCH3 + PNB equilibrium yields ΔH° = +0.7(2) kcal/ mol and ΔS° = +4.3(5) eu, suggesting PNB has somewhat higher Lewis acidity and is sterically more encumbered than B(C6F5)3. Solution ν(CN) values for PNBNCCH3 and (C6F5)3-BNCCH3 are 2365.3 and 2366.5 cm-1, respectively, which indicate strong Lewis acidity. PBBNCCH3 cannot be detected in the reaction of (C6F5)3BNCCH3 with PBB [PBB = tris-(2,2′,2″-perfluorobipheny)lborane] over prolonged periods at 60°C. In ethylene polymerization, PNB-derived cationic complexes 5, 6, 7, and 8 have catalytic activities similar to the B(C6F5)3-derived analogues, while 2 and 3 have substantially higher activities. In propylene polymerization, catalyst 1 has higher activity than the B(C6F5)3 analogue. In the case of ethylene and 1-hexene copolymerization, PNB-derived cationic complex 3 exhibits higher polymerization activity with similar 1-hexene incorporation versus the B(C6F5)3-derived cationic complex. In large-scale batch copolymerizations of ethylene and 1-octene mediated by CGCTiMe2, the PNB-based catalytic systems exhibit approximately twice the activity of the B(C6F5)3-based systems.

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