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

• Type: Article in International Scientific Journal
• Date: 2008

Authors

Houghton, J (Author) Other; Simonovic, S (Author) Other; Whitwood, AC (Author) Other; Douthwaite, RE (Author) Other; Sónia Carabineiro (Author) FEUP; Yuan, JC (Author) Other; Marques, MM (Author) Other; Gomes, PT (Author) Other

Journal

Title: Journal of Organometallic Chemistry

Vol. 693

Pages: 717-724

ISSN: 0022-328X

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 18 Citations

Scopus - 14 Citations

Other information

Authenticus ID: P-004-1GH

DOI: 10.1016/j.jorganchem.2007.11.060

Abstract (EN): 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 [ MCl(x)(kappa(2)-N, O-OC(6)H(2)R(1)R(2) C( H)= N-C(6)H(10)-Im) 2][Br](2) ( where M = Zr, x = 2, R(1)= R(2) = (t)Bu, 2; M = Zr, x = 2, R(1)= H, R(2)= NO(2), 3; M= V, x = 1, R(1)= R(2) = (t)Bu, 4; M = Cr, x = 1, R(1)= R(2) = (t)Bu, 5; M = Fe, x = 0, R(1)= R(2) = (t)Bu, 6; Im = 1-isopropyl-4-phenyl-3H-imidazol-1-ium-3-yl). 1 H and (13)C 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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8