Unique Insertion Mode of 1,7‐Octadiene in Copolymerization with Ethylene by a Constrained‐Geometry Catalyst

Naga, Naofumi; Toyota, Akinori

doi:10.1002/marc.200400250

Cited by 22 publications

(23 citation statements)

References 17 publications

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“…The signals at 40.4 (2″,4″), 38.3 (6″,9″), 36.2 (1″,5″), 28.6 (7″,8″), 26.7 ppm (3″) can be assigned to the CY 9 unit 13. The signals attributable to the α ″, β ″, and γ ″ methylene carbons appear at 35.3, 27.7 and 30.5 ppm, respectively 13. The formation of CY 7 units during ethylene/OD copolymerization by the intramolecular cyclization of OD units has been reported for several metallocene catalyst systems 4,5,7,11–13.…”

Section: Resultsmentioning

confidence: 88%

“…The 13 C NMR spectrum of an ethylene/OD copolymer (run 5) is shown in Figure 3 with peak assignments corresponding to the structures illustrated in Scheme . Naga and Toyota reported a unique OD insertion mode for ethylene/OD copolymerization with CGC‐Ti/methylisobutylaluminoxane under much milder conditions than those investigated herein ( T = 40 °C, P (C 2 H 4 ) = 14.6 psi) which formed a 1,5‐cyclononane (CY 9 ) unit 13. Strong signals detected in the 13 C NMR spectra of the copolymers under investigation confirm the formation of both 1,3‐cycloheptane (CY 7 ) and CY 9 units in addition to pendant 1‐hexenyl branches.…”

Section: Resultsmentioning

confidence: 99%

“…Strong signals detected in the 13 C NMR spectra of the copolymers under investigation confirm the formation of both 1,3‐cycloheptane (CY 7 ) and CY 9 units in addition to pendant 1‐hexenyl branches. The signals at 40.4 (2″,4″), 38.3 (6″,9″), 36.2 (1″,5″), 28.6 (7″,8″), 26.7 ppm (3″) can be assigned to the CY 9 unit 13. The signals attributable to the α ″, β ″, and γ ″ methylene carbons appear at 35.3, 27.7 and 30.5 ppm, respectively 13.…”

Section: Resultsmentioning

confidence: 99%

“…Several studies have been reported on ethylene/1,5‐hexadiene copolymerization with homogeneous metallocene catalysts, all showing that hexadiene is preferentially inserted into the backbone as five‐membered rings 2–10. In the case of ethylene copolymerization with 1,7‐octadiene (OD), the insertion mode of OD is strongly influenced by the catalyst system and polymerization conditions 4,5,7,9,11–13. Intramolecular cyclization of OD following addition insertion results in the inclusion of 1,3‐cycloheptane (CY 7 ) units in the polymer backbone.…”

Section: Introductionmentioning

confidence: 99%

“…Intramolecular cyclization of OD following addition insertion results in the inclusion of 1,3‐cycloheptane (CY 7 ) units in the polymer backbone. Recently, Naga and Toyota have reported that, when OD is copolymerized with ethylene using a constrained geometry catalyst, it undergoes a cyclization insertion in the penultimate position after a single ethylene insertion step, resulting in the formation of a 1,5‐cyclononane (CY 9 ) unit along the main chain 13. The 1,3‐disubstituted ring structures incorporated into the olefinic backbone by the addition‐cyclization reactions of 1,5‐hexadiene or 1,7‐octadieneOD adopt either a cis or a trans conformation, although preferential formation of the cis structure has been reported 7,10,12.…”

Section: Introductionmentioning

confidence: 99%

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Microstructural Characterization of Molecular Weight Fractions of Ethylene/1,7‐Octadiene Copolymers Made with a Constrained Geometry Catalyst

Sarzotti

Narayan

Whitney

et al. 2005

Macro Materials & Eng

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Summary: Ethylene was copolymerized with 1,7‐octadiene (OD) using a methylaluminoxane (MAO) activated constrained geometry catalyst (dimethylsilyl(N‐tert‐butylamido)(tetramethylcyclopentadienyl)titanium dichloride; CGC‐Ti) at 140 °C in toluene. The polymerization activity increased with the addition of small amounts of OD, reached a maximum, and then decreased at higher OD concentrations. The vinyl‐bond content of the polymers increased with increasing diene in the feed. Increasing OD concentrations led to the production of long chain branched (LCB) polyethylene (PE). Both 1,3‐cycloheptane (CY7) and 1,5‐cyclononane (CY9) units were identified in the copolymers, with the dominant CY9 structure accounting for approximately 53% percent of all rings. Selected copolymers were fractionated by molecular weight using a solvent/non‐solvent technique to obtain their detailed microstructure. The relative amounts of CY7 and CY9 structures were not a function of molecular weight. The number of vinyl functionalities decreased with increasing molecular weight, while the number of branches increased, indicating the incorporation of macromonomers with pendant or terminal vinyl groups.Molecular weight distributions of ethylene homopolymer and three fractions.magnified imageMolecular weight distributions of ethylene homopolymer and three fractions.

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Section: Resultsmentioning

confidence: 88%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Microstructural Characterization of Molecular Weight Fractions of Ethylene/1,7‐Octadiene Copolymers Made with a Constrained Geometry Catalyst

Sarzotti

Narayan

Whitney

et al. 2005

Macro Materials & Eng

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Double‐Decker‐Type Dinuclear Nickel Catalyst for Olefin Polymerization: Efficient Incorporation of Functional Co‐monomers

et al. 2013

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Double‐Decker‐Type Dinuclear Nickel Catalyst for Olefin Polymerization: Efficient Incorporation of Functional Co‐monomers

Takeuchi¹,

Chiba²,

Takano³

et al. 2013

Angew Chem Int Ed

134

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The ethylene polymerization and copolymerization of olefins catalyzed by dinuclear transition-metal complexes have recently attracted recent attention. [1] Both early-and latetransition-metal complexes with a dinuclear structure lead to an increase in the molecular weight in ethylene polymerization and in the co-monomer content for the copolymerization of ethylene with various co-monomers. [2] The stabilization of the growing polymer end and coordination of the comonomer are efficient in the bimetallic system. [3] Marks and co-workers synthesized a planar dinickel complex, which is supported by an aromatic bis(salicylaldimine) ligand (Scheme 1 a), [4] and found that copolymerization of ethylene with functionalized norbornenes and acrylates resulted in greater incorporation of the co-monomers than that with a mononuclear catalyst. [5] The catalysts, composed of the two nickel salicylaldimine centers and a spacer to join them, have been reported by several research groups independently (Scheme 1 b). [6] The polymer properties are influenced by the distance between nickel centers. Agapie and co-workers investigated olefin polymerization using their dinuclear complexes and revealed a dimer effect in inhibition of the catalysis by amine additives. [7] Lee and-co-workers reported the dinickel complex supported by a macrocyclic salicylaldimine ligand with a Ni···Ni separation of 8.869 (Scheme 1 c) and a moderate catalytic activity for ethylene polymerization. [8] We designed a dinuclear nickel catalyst supported by a rigid macrocyclic ligand, which forces the two nickel centers into close proximity, closer than reported for other catalysts so far. The catalyst is expected to show unique properties not only in ethylene polymerization but also in copolymerization with functionalized monomers, such as terminal dienes, [9] owing to the synergistic effects of the two metal centers. Herein, we show the synthesis of a new dinickel catalyst as well as its application in olefin polymerization.The dinuclear nickel complex 1 and its mononuclear analogue 2 are obtained from the reaction of deprotonated ligand precursors with [(Me 3 P) 2 NiMeCl]. [10] The molecular structure of 1, determined by X-ray crystallography (Figure 1), indicates that the methyl and PMe 3 ligands bonded to the two metal centers are positioned on the same side of the xanthene planes. The two nickel centers of 1 are separated by 4.73 , which is shorter than that in the previously reported dinuclear salicylaldimine nickel complexes (5.80-8.9 ). [5c, 6d, 7, 8] Both 1 and 2 catalyze ethylene polymerization in the presence of a [Ni(cod) 2 ] (cod = cyclo-1,5-octadiene) co-catalyst, which serves as a phosphine scavenger. The two complexes, however, differ significantly in the catalytic activity (2.1 g mmol Ni À1 h À1 atm À1 for 1 and 0.37 g mmol Scheme 1. Three classes of dinuclear salicylaldimine nickel catalyst for olefin polymerization. Figure 1. Structure of 1 determined by X-ray crystallography. Hydrogen atoms are omitted for clarity.

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Unique Insertion Mode of 1,7‐Octadiene in Copolymerization with Ethylene by a Constrained‐Geometry Catalyst

Cited by 22 publications

References 17 publications

Microstructural Characterization of Molecular Weight Fractions of Ethylene/1,7‐Octadiene Copolymers Made with a Constrained Geometry Catalyst

Microstructural Characterization of Molecular Weight Fractions of Ethylene/1,7‐Octadiene Copolymers Made with a Constrained Geometry Catalyst

Double‐Decker‐Type Dinuclear Nickel Catalyst for Olefin Polymerization: Efficient Incorporation of Functional Co‐monomers

Double‐Decker‐Type Dinuclear Nickel Catalyst for Olefin Polymerization: Efficient Incorporation of Functional Co‐monomers

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