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Volumn 24, Issue 9, 2005, Pages 2039-2050

Investigations into the mechanism of activation and initiation of ethylene polymerization by bis(imino)pyridine cobalt catalysts: Synthesis, structures, and deuterium labeling studies

Author keywords

[No Author keywords available]

Indexed keywords

CATALYSTS; COMPLEXATION; DEUTERIUM; ETHYLENE; MOLECULAR STRUCTURE; NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY; POLYMERIZATION; SYNTHESIS (CHEMICAL);

EID: 18444398323     PISSN: 02767333     EISSN: None     Source Type: Journal    
DOI: 10.1021/om049032b     Document Type: Article
Times cited : (82)

References (70)
  • 6
    • 18444374543 scopus 로고    scopus 로고
    • Johnson, L. K.; Killian C. M.; Bennett, A. M. A.; Coughlin, E. B.; Ittel, S. D.; Parthasarathy, A.; Tempel, D. J.; Brookhart, M. S. WO 9603010, 1996
    • (c) Johnson, L. K.; Killian C. M.; Bennett, A. M. A.; Coughlin, E. B.; Ittel, S. D.; Parthasarathy, A.; Tempel, D. J.; Brookhart, M. S. WO 9603010, 1996.
  • 27
    • 18444418986 scopus 로고    scopus 로고
    • (b) For an overview see: Erker, G. Acc. Chem. Res. 2001, 34, 47.
    • (2001) Acc. Chem. Res. , vol.34 , pp. 47
    • Erker, G.1
  • 39
    • 18444378568 scopus 로고    scopus 로고
    • note
    • While this description of the systems as cobalt(II) bound to a ligand radical may be correct, we will continue to refer to these systems as Co(I) in this article in order to avoid confusion with cobalt(II) complexes such as 1. The distribution of electrons within the cobalt(I) complexes docs not affect our later mechanistic experiments and conclusions.
  • 40
    • 18444381866 scopus 로고    scopus 로고
    • note
    • 3 or MAO; the MAO-activated cation will be referred to as 13-MAO.
  • 43
    • 18444392842 scopus 로고    scopus 로고
    • note
    • 2H NMR data to be obtained. Although the cobalt (I) complexes are generally unstable in chlorinated and brominated solvents, leading to unidentified paramagnetic products, no decomposition is seen in the sterically protected 2-chlorotoluene over a period of at least 5 h.
  • 44
    • 18444397587 scopus 로고    scopus 로고
    • note
    • Dry MAO is the white solid obtained by removal of solvent and trialkylaluminums from a solution of MAO, followed by repeated slurrying in heptane and removal of the volatile components.
  • 56
    • 18444409495 scopus 로고    scopus 로고
    • note
    • 4; no equilibrium is observed. It thus appears that the tertiary amine is too bulky to interact with the sterically protected cobalt center.
  • 59
    • 18444403866 scopus 로고    scopus 로고
    • note
    • 5) groups were detectable in the polymer.
  • 60
    • 18444416962 scopus 로고    scopus 로고
    • note
    • Errors in all quantitative measurements obtained by NMR spectroscopy are estimated to be ±20%, arising mainly from errors in the integration of NMR signals.
  • 61
    • 18444376886 scopus 로고    scopus 로고
    • note
    • 1H NMR spectrum, the presence of very low amounts of chain transfer cannot be ruled out completely.
  • 62
    • 18444389889 scopus 로고    scopus 로고
    • note
    • Insertion into the Co-H bond that results from a vinylic C-H activation (the less sterically demanding bond into which insertion could occur) would result in a polymer or oligomer with one methyl and one vinyl bond (as observed) whether the polymer was terminated by β-hydrogen elimination or reductive elimination. Insertion into the Co-vinyl bond would afford chains with one methyl and one vinyl chain end only if termination occurred via reductive elimination. If termination occurred by β-hydrogen elimination, dienes would result, which would be detectable among the oligomeric products.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.