| 433732-09-3

• CAS: 433732-09-3
• 化学式: C₁₉H₂₂Hf
• 分子量: 428.874
• InChiKey: WHYCISPWGLUZGN-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  None
• 重原子数：
  None
• 可旋转键数：
  None
• 环数：
  None
• sp3杂化的碳原子比例：
  None
• 拓扑面积：
  None
• 氢给体数：
  None
• 氢受体数：
  None

反应信息

• 作为反应物：
  描述：

  、 三(五氟苯基)硼烷 以 氘代甲苯 为溶剂， 生成
  参考文献：
  名称：

  Propene polymerization using ansa-metallocenium ions: Catalyst deactivation processes during monomer consumption and molecular structures of the products formed

  摘要：

  Propene polymerization using ansa-metallocene dialkyl complexes [Me2C(Cp)IndMMe2] (1a; M = Zr) and (1b; M = Hf) was studied using B(C6F5)(3) as a stoichometric activator. The initial rates of propene uptake as well as the steady-state rates of propene consumption are dramatically increased in the presence of excess borane using la and to a lesser extent 1b. H-1 and F-19 NMR experiments at B:Zr ratios of 1:1 and 1.2:1 reveal that the by-products produced following consumption of monomer are also sensitive to B:Zr stoichiometry. Under the former conditions, initiation is inefficient and unreacted ion-pairs [Me2C(CP)IndZrMe][MeB(C6F5)(3)] (2a-b) effect C-H activation of the unsaturated oligomers that form to produce pi-allyl complexes [Me2C(Cp)IndZr(eta(3)-2-R-C3H4)][MeB(C6F5)(3)] (4a) [R = -(CH2CHMe)(n)CH2CH2CH3] and methane; these oligomeric complexes were identified by comparison to pi-allyl complexes 4b (R = Me) and 4c (R = CH2CMe3) prepared from ion-pairs 2a-b and either isobutene or 2,4,4-trimethylpentene. Complex 4b was structurally characterized and presents a highly distorted pi-methallyl ligand. In the presence of excess borane, initiation is efficient, and the principal by-products formed are Zr-borohydride complexes Me2C(Cp)IndZrMe(mu-H)B(C6F5)(3) (5a-b). The major isomer present was identified by comparison to the spectroscopic data observed for its Hf-analog 6 with could be isolated from these reactions and was structurally characterized. Complexes 5 are detected after consumption of monomer is complete whereas complex 6 was formed competitively during consumption of monomer and both are relatively unreactive towards subsequent monomer insertion. Thus, the formation of these g-borohydride complexes is a reversible deactivation pathway for some ansa-metallocenium ions, and that excess borane may serve to reactivate them towards further insertion. (c) 2005 Published by Elsevier Ltd.

  DOI：

  10.1016/j.poly.2005.02.005
• 作为产物：
  描述：

  bis(dimethylamido)[2-(η(5)-cyclopentadienyl)-2-(η(5)-indenyl)propane]hafnium 、 三甲基铝 以 正己烷 为溶剂， 以96%的产率得到
  参考文献：
  名称：

  Counterion Effects on Propylene Polymerization Using Two-State ansa-Metallocene Complexes

  摘要：

  Propylene polymerization using unsymmetrical, ansa-metallocene complexes Me2Y(Ind)CpMMe2 (Y = Si, C, M = Zr, Y = C, M = Hf) and the co-initiators methyl aluminoxane (PMAO), B(C6F5)(3), and [Ph3C][B(C6F5)41 was studied at a variety of propylene concentrations. Modeling of the polymer microstructure reveals that the catalysts derived from Me2Si(ind)CpZrMe2 and each of these co-initiators function under conditions where chain inversion is much faster than propagation (Curtin-Hammett conditions). Surprisingly, the microstructure of the PP formed was essentially unaffected by the nature of the counterion, suggesting similar values for the fundamental parameters inherent to two-state catalysts. The tacticity of PIP was sensitive to changes in [C3H6] in the case of catalysts derived from Me2C(ind)CpHfMe2 and PMAO, or [Ph3C][B(C6F5)(4)], but the average tacticity of the polymer produced at a given [C3H6] decreased in the order [Ph3C][B(C6F5)41 > PMAO. With B(C6F5)3, the polymer formed was more stereoregular, and its microstructure was invariant to changes in monomer concentration. The PIP pentad distributions in this case could be modeled by assuming that all three catalyst/cocatalyst combinations function with different values for the relative rates of insertion to inversion (A) but otherwise feature essentially invariant, intrinsic stereoselectivity for monomer insertion (alpha, beta), while the relative reactivity/stability (g/K) of the isomeric ion-pairs present seems to be only modestly affected, if at all. Similar conclusions can also be made about the published propylene polymerization behavior of the C-s-symmetric Me2C(Flu)CpZrMe2 complex with different counterions. For every counterion investigated, the principle difference appears to be the operating regime (A) rather than intrinsic differences in insertion stereoselectivity (a). Surprisingly, the ordering of the various counterions with respect to A does not agree with commonly accepted ideas about their coordinating ability. In particular, catalysts when activated with B(C6F5)3 appear to function at low values of Delta as compared to those featuring B(C6F5)(4) (less coordinating) and FAI[(o-C6F5)C6F4](3) (more coordinating) or PMAO (more coordinating) counterions where the ordering in Delta is MeB(C6F5)(3) < B(C6F5)(4) < FAI[(o-C6F5)C6F4](3) approximate to PMAO. Possible reasons for this behavior are discussed.

  DOI：

  10.1021/ja0207706