Copolymerization of Propene and Nonconjugated Diene Involving Intramolecular Cyclization with Metallocene/Methylaluminoxane

Naofumi Naga, Takeshi Shiono, Tomiki Ikeda

Research output: Contribution to journalArticle

83 Citations (Scopus)

Abstract

Copolymerizations of propene with 1,5-hexadiene and 1,7-octadiene were carried out with isospecific rac-dimethylsilylenebis(indenyl)zirconium dichloride (1) and syndiospecific diphenylmethylene-(cyclopentadienyl)(9-fluorenyl)zirconium dichloride (2) combined with methylaluminoxane. Microstructures of the copolymers were determined by 1H NMR, 13C NMR, and DEPT (distortionless enhancement of polarization transfer) spectroscopies. Incorporation of nonconjugated dienes in the copolymer was higher with 2 than with 1. Intramolecular cycloaddition of the nonconjugated dienes proceeded regardless of the catalysts. Stereoselectivity in cycloaddition of 1,5-hexadiene was investigated based on the structures of isolated methylene-1,3-cyclopentane units. It was found that 1,5-hexadiene was inserted stereospecifically by enantiomorphic site control with both catalysts. The diastereoselectivity of the cyclization step of 1,2-inserted 1,5-hexadiene was, however, found to be independent of stereospecificity of the catalyst. The cyclization selectivity of 1,5-hexadiene copolymerization was higher than that of 1,7-octadiene copolymerization. I gave the copolymers with higher selective in cyclization than 2 in the propene/1,5-hexadiene copolymerization, while the opposite tendency was observed in the propene/1,7-octadiene copolymerization. Decrease of cyclization selectivity was observed with the increases of 1,5-hexadiene and 1,7-octadiene concentration in both copolymerizations. Propene insertion could disturb the cyclization of 1,2-inserted dienes, which declined the cyclization selectivity of the copolymers, except propene/1,5-hexadiene copolymerization with 2.

Original languageEnglish
Pages (from-to)1348-1355
Number of pages8
JournalMacromolecules
Volume32
Issue number5
Publication statusPublished - 1999 Mar 9
Externally publishedYes

Fingerprint

Cyclization
Copolymerization
Propylene
Copolymers
Cycloaddition
Zirconium
Catalysts
Nuclear magnetic resonance
Stereoselectivity
Catalyst selectivity
Cyclopentanes
metallocene
1,5-hexadiene
propylene
Spectroscopy
Polarization
Microstructure
1,7-octadiene

ASJC Scopus subject areas

  • Materials Chemistry

Cite this

Copolymerization of Propene and Nonconjugated Diene Involving Intramolecular Cyclization with Metallocene/Methylaluminoxane. / Naga, Naofumi; Shiono, Takeshi; Ikeda, Tomiki.

In: Macromolecules, Vol. 32, No. 5, 09.03.1999, p. 1348-1355.

Research output: Contribution to journalArticle

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AB - Copolymerizations of propene with 1,5-hexadiene and 1,7-octadiene were carried out with isospecific rac-dimethylsilylenebis(indenyl)zirconium dichloride (1) and syndiospecific diphenylmethylene-(cyclopentadienyl)(9-fluorenyl)zirconium dichloride (2) combined with methylaluminoxane. Microstructures of the copolymers were determined by 1H NMR, 13C NMR, and DEPT (distortionless enhancement of polarization transfer) spectroscopies. Incorporation of nonconjugated dienes in the copolymer was higher with 2 than with 1. Intramolecular cycloaddition of the nonconjugated dienes proceeded regardless of the catalysts. Stereoselectivity in cycloaddition of 1,5-hexadiene was investigated based on the structures of isolated methylene-1,3-cyclopentane units. It was found that 1,5-hexadiene was inserted stereospecifically by enantiomorphic site control with both catalysts. The diastereoselectivity of the cyclization step of 1,2-inserted 1,5-hexadiene was, however, found to be independent of stereospecificity of the catalyst. The cyclization selectivity of 1,5-hexadiene copolymerization was higher than that of 1,7-octadiene copolymerization. I gave the copolymers with higher selective in cyclization than 2 in the propene/1,5-hexadiene copolymerization, while the opposite tendency was observed in the propene/1,7-octadiene copolymerization. Decrease of cyclization selectivity was observed with the increases of 1,5-hexadiene and 1,7-octadiene concentration in both copolymerizations. Propene insertion could disturb the cyclization of 1,2-inserted dienes, which declined the cyclization selectivity of the copolymers, except propene/1,5-hexadiene copolymerization with 2.

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