Bis(3,5-dimethylpyrazol-1-ato) zirconiumcomplexes as precursors for ethylene polymerisation upon activation with MAO: Syntheses, characterisation and X-ray molecular structure of [Zr(η2-3,5-Me2Pz)2Cl21-3,5-Me2PzH)2] · (3,5-Me2PzH) and [Zr(η2-3,5-Me2Pz)2(CH2Ph)2] (3,5-Me2Pz = 3,5-dimethylpyrazol-1-ato)

Sanz, M, Mosquera, MEG, Cuenca, T, de Arellano, CR, Schormann, M and Bochmann, M (2007) Bis(3,5-dimethylpyrazol-1-ato) zirconiumcomplexes as precursors for ethylene polymerisation upon activation with MAO: Syntheses, characterisation and X-ray molecular structure of [Zr(η2-3,5-Me2Pz)2Cl21-3,5-Me2PzH)2] · (3,5-Me2PzH) and [Zr(η2-3,5-Me2Pz)2(CH2Ph)2] (3,5-Me2Pz = 3,5-dimethylpyrazol-1-ato) Polyhedron, 26 (18). pp. 5339-5348.

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    Abstract

    The bis(3,5-dimethylpyrazol-1-ato) zirconium complex [Zr(η2-3,5-Me2Pz)2(NMe2)2(NHMe2)2] (2) is obtained by treatment of [Zr(NMe2)4] with 2 equiv. of 3,5-dimethylpyrazole 1. The reaction of the [ZrCl4(THF)2] adduct with 2 equiv. of the potassium salt of 1 affords the dichloro derivative [Zr(η2-3,5-Me2Pz)2Cl2]n (3), while reaction with 4.1 equiv. of 1 in the presence of 2.1 equiv. of NEt3 affords the dichloro pyrazole adduct [Zr(η2-3,5-Me2Pz)2Cl21-3,5-Me2PzH)2] (4). Treatment of [Zr(CH2Ph)4] with 2 equiv. of 1 gives the dibenzyl complex [Zr(η2-3,5-Me2Pz)2(CH2Ph)2] (5) via alkane elimination. Compound 4 presents fluxional behaviour in CDCl3 solution, which was studied and quantified by variable-temperature proton NMR experiments. All compounds were characterised by routine analyses and the molecular structures of 4 and 5 were established by single-crystal X-ray diffraction studies. The performance of precursors 3 and 5 was evaluated in ethylene polymerisation upon activation with MAO.

    Item Type: Article
    Faculty \ School: Faculty of Science > School of Chemistry
    Depositing User: Rachel Smith
    Date Deposited: 02 Nov 2010 17:48
    Last Modified: 16 Jun 2011 15:09
    URI: https://ueaeprints.uea.ac.uk/id/eprint/10541
    DOI: 10.1016/j.poly.2007.08.001

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