title: Methylene-bridged bimetallic α-diimino nickel(II) complexes: synthesis and high efficiency in ethylene polymerization.
abstract: A series of 1,2-bis(arylimino)acenaphthylidenes (L1-L5) and their corresponding 4,4'-methylenebis(1-(2,6-diisopropylphenylimino)-2-(arylimino)acenaphthylene) derivatives (L6-L10) were synthesized and used to form mono-nuclear nickel bromides LnNiBr2 (n = 1-5, Ni1-Ni5) and bi-nuclear nickel halides LnNi2X4 (n = 6-10: X = Br, Ni2-1-Ni2-5; n = 4, X = Cl, Ni2-6). All the organic compounds were fully characterized by FT-IR spectra, NMR measurements and elemental analysis. The nickel complexes were characterized by FT-IR spectra and elemental analysis and the molecular structures of the representative complexes Ni1, Ni2-1 and Ni2-3 were confirmed by single-crystal X-ray diffraction. Upon activation with either Et2AlCl or MAO, all the nickel complex pre-catalysts exhibited high activity toward ethylene polymerization over the temperature range from ambient to 50 °C. In general, the bi-nuclear complexes showed a positive synergetic effect with higher activity than their mono nuclear analogs. The resultant polyethylene possessed higher molecular weight and a high degree of branching.
authors: School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
authors: Shaoliang
authors: S
authors: Kong
authors: Kuifeng
authors: K
authors: Song
authors: Tongling
authors: T
authors: Liang
authors: Cun-Yue
authors: CY
authors: Guo
authors: Wen-Hua
authors: WH
authors: Sun
authors: Carl
authors: C
authors: Redshaw
mesh_terms: D005030:Ethylenes / Q000737:chemistry*; D007097:Imines / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D058105:Polymerization
chemical_list: D005030:Ethylenes; D007097:Imines; D009942:Organometallic Compounds; D009532:Nickel; C036216:ethylene