Preparation and crystal structures of the complexes (η5-C5H3TMS–CMe2–η5-C13H8)MCl2 and [3,6-ditButC13H6–SiMe2–NtBu]MCl2 (M=Hf, Zr or Ti): mechanistic aspects of the catalytic formation of a isotactic–syndiotactic stereoblock-type polypropylene
摘要:
The reaction of MCl4, (M = Zr or Hf) with the dilithium salt of 2-(3-trimethylsilyl-cydopentadienyl)-2-florenylpropane in pentane leads to the formation of the complexes (eta (5)-C5H3TMS-CMe2-eta (5)-C13H8)MCl2 (M = Zr or Hf; TMS = trimethylsilyl). The X-ray diffraction data show that both the fluorenyl and cyclopentadienyl groups are 175 bonded to the transition metal in these complexes in the solid phase. The polymerization data and the polymer microstructure, however, clearly indicate that at least after the activation with MAO the active species formed with these molecules show very dynamic bonding behavior and their substituted cyclopentadienyl group changes its hapticity rapidly and frequently during the course of the polymerization. (C) 2001 Published by Elsevier Science B.V. All rights reserved.
“Constrained Geometry” Group 3 Metal Complexes of the Fluorenyl-Based Ligands [(3,6-<sup>t</sup>Bu<sub>2</sub>Flu)SiR<sub>2</sub>N<sup>t</sup>Bu]: Synthesis, Structural Characterization, and Polymerization Activity
作者:Evgueni Kirillov、Loic Toupet、Christian W. Lehmann、Abbas Razavi、Jean-François Carpentier
DOI:10.1021/om0304210
日期:2003.10.1
hydrido complex “[(3,6-tBu2Flu)SiMe2NtBu)YH(THF)]n” (3). Deprotonation of 1a with 1 and 2 equiv of nBuLi gave [(3,6-tBu2C13H6)SiMe2NHtBu]Li (5) and [(3,6-tBu2C13H6)SiMe2NtBu]Li2 (4), respectively, both of which were characterized crystallographically. Salt elimination reactions between LnCl3(THF)n precursors (Ln = Y, La, Nd) and 1 equiv of 4 gave mixtures of complexes, from which ionic complexes that
Y(CH 2 SiMe 3)3(THF)2与双旋配体[(3,6- t Bu 2 C 13 H 7)SiR 2 NH t Bu]之间的烷烃消除(R = Me,1a ; R = Ph,图1b),得到[η 3:η 1 - ((3,6-吨卜2 ç 13 ħ 6)SIR 2 ñ吨卜)Y(CH 2森达3)(THF)2 ](R = Me中,图2a ; R = Ph,2b)。2a在甲苯溶液中是热稳定的,并显示出与THF解离有关的动力学行为,而2b是热不稳定的。的反应图2a用H 2或PhSiH 3导致了推定的氢基复合物“[(3,6-吨卜2流感)森达2 Ñ吨丁基)YH(THF)] ñ ”(3)。用1和2当量的n BuLi对1a进行质子化,得到[(3,6- t Bu 2 C 13 H 6)SiMe 2 NH t Bu] Li(5)和[(3,6- t Bu 2 C 13 H 6)SiMe 2 N t Bu] Li