Synthesis of a [(?-Cyano-nacnac)Cp]zirconium complex and its remote activation for ethylene polymerization

Cabrera A.R.; Valderrama M.; Rojas R.S.; Schneider, Y; Frohlich, R; Kehr, G; Erker, G

Keywords: complexes, systems, system, activation, polymerization, complexation, ray, catalysts, ethylene, diffraction, catalyst, zirconium, ziegler-natta, activity, mao, remote, compounds, reference, X, molar, Cyanides, Equivalent, Catalytic, Acetylacetonates, Cyanation, N-butyllithium


The NC-nacnacH ligand (2) was prepared by the deprotonation of the unsymmetrically N5-phenyl, N1-2,6-diisopropylphenyl substituted bis(imino) acetylacetonate nacnacH system (1) with n-butyllithium followed by cyanation with tosyl cyanide. Subsequent deprotonation (KH) gave the [NC-nacnac]K salt (3), which was transmetalated by reacting it with CpZrCl 3(dme), to yield the complex (NC-nacnac)CpZrCl 2 (5). Addition of one molar equivalent of B(C 6F 5) 3 gave [(C 6F 5) 3B-NC-nacnac]CpZrCl 2 (6). The compounds 2, 5, and 6 were characterized by X-ray diffraction. Activation of 5 with MAO gave an active homogeneous Ziegler-Natta catalyst for ethylene polymerization. The (NC-nacnac)CpZrCl 2/MAO system is ca. 7 times more active than the CN-free reference system (nacnac)CpZrCl 2 (4)/MAO. The B(C 6F 5) 3-containing system 6/MAO has an activity similar to 5/MAO but allows for much lower MAO concentration before the catalytic activity ceases. © 2010 American Chemical Society.

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Título de la Revista: ORGANOMETALLICS
Volumen: 29
Número: 22
Fecha de publicación: 2010
Página de inicio: 6104
Página final: 6110