Ethylene Polymerization and Copolymerization by Palladium and Nickel Catalysts Containing Naphthalene-Bridged Phosphine–Sulfonate Ligands
作者:Zixia Wu、Min Chen、Changle Chen
DOI:10.1021/acs.organomet.6b00076
日期:2016.5.23
A series of naphthalene-bridged phosphine sulfonate ligands and the corresponding Pd(II) complexes [kappa(2)(P,O)-2-(R2P)-1-naphthalenesulfonato]Pd(Me)(dmso) (1, R = Ph; 2, R = o-MeO-C6H4.; 3, R = Cy) and Ni(II) complexes [kappa(2)(P,O)-2-(R2P)-1-naphthalenesulfonato]Ni(eta(3)-C3H5) (Ni-1, R = o-MeO-C6H4; Ni-2, R = Cy) have been prepared and characterized. The analogous benzo-bridged phosphine sulfonate Pd(II) complex [kappa(2)(P,O)(R2P)-benzenesulfonato]Pd(Me)(dmso) (2', R = o-MeO-C6H4) and Ni(II) complex [kappa(2)(P,O)-(R2P)-benzenesulfonato]Ni(eta 3-C3H5) (Ni-1', R = o-MeO-C6H4) were prepared for comparison. In ethylene polymerization, complex 2 showed activity of up to 7.5 x 10(6) g mol(-1) h(-1), which is among the most active palladium catalysts for ethylene homopolymerization. Under the same conditions, complex 2 showed up to 1 order of magnitude higher catalytic activity than complex 2', generating polyethylene with slightly smaller molecular weight and similar branching density. The Ni(II) complex Ni-1 was also more active than complex generating polyethylene with up to 1 order of magnitude higher molecular weight. In ethylene methyl acrylate copolymerization, complex 2 showed lower activity, affording a copolymer with higher methyl acrylate incorporation and higher copolymer molecular weight in comparison to complex 2'.