摘要
New neutral nickel(II) complexes bearing asymmetric β-ketoiminato (N,O) ligands (5a-c), [(2,6-iPr2C6H 3)NC(R2)C(H)C(R1)O]Ni(Ph)(PPh3), have been synthesized. X-ray crystal structures reveal that each of complexes 5a-c adopts a near square-planar coordination geometry and the triphenylphosphine group is always trans to the arylamine group. With modified methylaluminoxane (MMAO) as a cocatalyst, complexes 5a-c can promote the polymerization of methyl methacrylate (MMA) in excellent yields (>98%), producing syndiotactic-rich PMMAs (rr around 70%). It is very exciting that the 5a-c/MMAO catalyst systems exhibit highly catalytic activities for the copolymerization of ethylene with MMA, producing high molecular weight functionalized polyethylenes with up to 16.7 mol % of methacrylate units built into the moderately branched polyethylene backbone. Further mechanistic studies have shown that PMMAs and copolymers obtained using these complexes possibly arise from a coordination-insertion mechanism rather than a radical mechanism.
源语言 | 英语 |
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页(从-至) | 2502-2510 |
页数 | 9 |
期刊 | Organometallics |
卷 | 24 |
期 | 10 |
DOI | |
出版状态 | 已出版 - 9 5月 2005 |
已对外发布 | 是 |