Transition-metal complexes of phenoxy-imine ligands modified with pendant imidazolium salts: Synthesis, characterisation and testing as ethylene polymerisation catalysts

Jennifer Houghton, Stevan Simonovic, Adrian C. Whitwood, Richard E. Douthwaite, Sonia A. Carabineiro, Jian-Chao Yuan, Maria M. Marques, Pedro T. Gomes

Research output: Contribution to journalArticlepeer-review

Abstract

Reaction between 3-((1R,2R)-2-{[1-(3,5-di-tert-butyl-2-hydroxy-phenyl)-meth-(E)-ylidene]-amino}-cyclohexyl)-1- isopropyl-4-phenyl3H- imidazol-1-ium bromide (1a) or the derivative 3-((1R,2R)-2-{[ 1-(2-hydroxy-5-nitro-phenyl)-meth-( E)- ylidene]- amino}- cyclohexyl)1- isopropyl- 4-phenyl-3H-imidazol-1-ium bromide (1b) and metal halides MCl(x center dot)yTHF (M = Zr, x = 4, y = 2; M= V, x = y = 3; M = Cr, x = y = 3), in THF, at -78 degrees C gives the metal complexes of general formula [ MClx(kappa(2)-N, O-(OC6H2RR2)-R-1 C( H)= N-C6H10-Im) 2][Br](2) ( where M = Zr, x = 2, R-1= R-2 = Bu-t, 2; M = Zr, x = 2, R-1= H, R-2= NO2, 3; M= V, x = 1, R-1= R-2 = Bu-t, 4; M = Cr, x = 1, R-1= R-2 = Bu-t, 5; M = Fe, x = 0, R-1= R-2 = Bu-t, 6; Im = 1-isopropyl-4-phenyl-3H-imidazol-1-ium-3-yl). 1 H and C-13 NMR spectroscopy of 2 and 3 indicate kappa(2)- N, O-ligand coordination via the phenoxy-imine moiety with pendant imidazolium salt that is corroborated by a single crystal structure of 6. Compounds 2, 3, 4 and 5 were tested as precatalysts for ethylene polymerisation in the presence of methylaluminoxane (MAO) cocatalyst, showing low activity. Selected polymer samples were characterised by GPC showing multimodal molecular weight distributions. (c) 2007 Elsevier B. V. All rights reserved.

Original languageEnglish
Pages (from-to)717-724
Number of pages8
JournalJOURNAL OF ORGANOMETALLIC CHEMISTRY
Volume693
Issue number4
DOIs
Publication statusPublished - 15 Feb 2008

Keywords

  • chromium
  • iron
  • zirconium
  • phenoxy-imine ligands
  • imidazolium salts
  • ethylene polymerisation
  • LIVING OLEFIN POLYMERIZATION
  • SCHIFF-BASE LIGANDS
  • TITANIUM COMPLEXES
  • CHELATE LIGANDS
  • FI CATALYSTS
  • PROPYLENE POLYMERIZATION
  • ZIRCONIUM COMPLEXES
  • SALICYLALDIMINATO COMPLEXES
  • ETHENE POLYMERIZATION
  • BLOCK-COPOLYMERS

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