Scandium and yttrium complexes of a heteroscorpionate [N,N,O]-donor-set ligand: Synthesis, characterization and catalytic activity in ethylene polymerization
摘要:
New scandium and yttrium complexes ScL2(bpzmp)(THF) {L = Cl (1); L = CH2Si(CH3)(3) (3)}, YL2(bpzmp) {L = Cl ( 2); L = OTf (5)} and Y(CH2SiMe3)(2)(bpzmp)(THF) (4) bearing the heteroscorpionate bpzmp ligand {bpzmp = (3,5-Bu-t(2)-2-phenoxo) bis(3,5-Me-2-pyrazol-1-yl) methane} have been synthesized and characterized by means of NMR and Mass spectroscopy. The tridentate monoanionic ligand resulted kappa(3)-coordinated to the metal via the oxygen and both the sp(2) nitrogen atoms of the heterocycles, producing complexes in CS symmetry.The behavior of 1-4 in ethylene polymerization was investigated after proper activation with different activating agents. Complex 4, in combination with the Bronsted or Lewis acids [PhNMe2H][B(C6F5)(4)] or [Ph3C][B(C6F5)(4)], produced linear high molecular weight polyethylene in good yield. (C) 2009 Elsevier B.V. All rights reserved.