884488-70-4Relevant academic research and scientific papers
Synthesis, characterization, and ethylene polymerization activities of neutral nickel(II) complexes derived from anilino-substituted enone ligands bearing trifluoromethyl and trifluoroacetyl substituents
Zhang, Lei,Brookhart, Maurice,White, Peter S.
, p. 1868 - 1874 (2008/10/09)
A series of neutral Ni(II) complexes derived from anilino-substituted enone ligands bearing electron-withdrawing trifluoromethyl and trifluoroacetyl groups have been synthesized and characterized: [η2-ArNC(R 1)C=C(R2)C(O)CF3]Ni(PPh3)Ph (3a, Ar = 3,5-i-Pr2C6H3, R1 = H, R 2 = COCF3; 3b, Ar = 3,5i-Pr2C6H 3, Ri = Me, R2 = COCF3; 3c, Ar = 3,5-i-Pr 2C6H3, R1 = Me, R2 = H; 3d, Ar = 3,5-Me2C6H3, R1 = Me, R2 = COCF3). When they are activated with either Ni(COD)2 or B(C6F5)3, these complexes are active for the polymerization of ethylene to branched polyethylenes. Complex 3a is especially active and long-lived, with a turnover frequency of 5 × 105 at 60 °C and 200 psig of ethylene, a half-life exceeding 15 h at 35 °C, and a total turnover number exceeding 106 at 35 °C and 200 psig. Molecular weights and degrees of branching of polyethylenes obtained from 3a are reported as a function of reaction temperature and ethylene pressure.
