Vanadium olefin polymerization catalysts: NMR spectroscopic characterization of V(III) intermediates

Igor E. Soshnikov, Nina V. Semikolenova, Konstantin P. Bryliakov, Vladimir A. Zakharov, Evgenii P. Talsi

Research output: Contribution to journalReview articlepeer-review

6 Citations (Scopus)

Abstract

Vanadium(III) species formed upon reacting α-diimine (1) and bis(imino)pyridine (5) vananadium(III) pre-catalysts with MAO, AlMe2Cl, AlMe2Cl/[Ph3C][B(C6F5)4], and AlMe3/[Ph3C][B(C6F5)4] have been characterized in detail by 1H, 2H, and 19F NMR spectroscopy; the VIII-CH3 moiety has been observed by 1H and 2H NMR spectroscopy. For complex 1, zwitterion-like species [L'VIIIR2 +···MeMAO-] and ion pairs [L'VIIIR2(THF)2]+[A]- (L' = 1,4-bis-3,5-dimethylphenyl-2,3-dimethyl-1,4-diazabuta-1,3-diene; [A]- = [MeMAO]- or [B(C6F5)4]-) have been identified. The outer-sphere ion pairs of the type [L(Cl)VIII(μ-Cl)2AlMe2]+[A]-, [L(Me)VIII(μ-Cl)2AlMe2]+[A]-, [LVIIICl2(THF)]+[A]- and [LVIII(Cl)Me(THF)]+[A]- (L = 2,6-bis[1-(2,6-dimethylphenylimino)ethyl]pyridine; [A]- = [AlMe3Cl]- or [B(C6F5)4]-) have been found in the systems based on the complex 5. The nature of the vanadium species active in ethylene polymerization and the catalyst deactivation pathways are discussed.

Original languageEnglish
Pages (from-to)4-13
Number of pages10
JournalJournal of Organometallic Chemistry
Volume867
DOIs
Publication statusPublished - 15 Jul 2018

Keywords

  • Active species
  • Bis(imino)pyridine
  • Ethylene polymerization
  • NMR
  • Vanadium
  • α-diimine
  • bis(imino)pyridine
  • ACTIVATION
  • ALKYL
  • bis(imino) pyridine
  • EPR
  • STATE
  • IRON(II)
  • ETHYLENE POLYMERIZATION
  • H-1
  • COMPLEXES SYNTHESIS
  • LIGAND
  • alpha-diimine

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