[(1,2,4-tri-tert-butylcyclopentadienyl)2Ce(η2-methoxymethylene)] | 1160248-87-2

• 英文名称: [(1,2,4-tri-tert-butylcyclopentadienyl)2Ce(η2-methoxymethylene)]
• CAS: 1160248-87-2
• 化学式: C₃₆H₆₃CeO
• 分子量: 652.016
• InChiKey: PFCZBMDUFPFZRA-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
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• 重原子数：
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• 可旋转键数：
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• 环数：
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• sp3杂化的碳原子比例：
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• 拓扑面积：
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• 氢给体数：
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• 氢受体数：
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反应信息

• 作为反应物：
  描述：

  [(1,2,4-tri-tert-butylcyclopentadienyl)2Ce(η2-methoxymethylene)] 以 全氘代环己烷 为溶剂， 生成 [(1,2,4-tri-tert-butylcyclopentadienyl)(1,2,4-tri-tert-butylcyclopentadienyl(-H))Ce]
  参考文献：
  名称：

  Hydrogen for X-Group Exchange in CH₃X (X = Cl, Br, I, OMe, and NMe₂) by Monomeric [1,2,4-(Me₃C)₃C₅H₂]₂CeH: Experimental and Computational Support for a Carbenoid Mechanism

  摘要：

  The reactions between [1,2,4-(Me3C)(3)C5H2](2)CeH, referred to as Cp'2CeH, and CH3X, where X is Cl, Br, I, OMe, and NMe2, are described. The reactions fall into three distinct classes. Class a, where X = Cl, Br, and I, rapidly form Cp'2CeX and CH4 without formation of identifiable intermediates in the H-1 NMR spectra. Class b, where X = Me, proceeds rapidly to CP'Ce-2(eta(2)-CH2OMe) and H-2 and then to CP'2CeOMe and CH4. The methoxymethyl derivative is sufficiently stable to be isolated and characterized, and it is rapidly converted to Cp'2CeOMe in the presence of BPh3. Class c, where X = NMe2, does not result in formation of Cp'2CeNMe2, but deuterium labeling experiments show that H for D exchange occurs in NMe3. Density functional calculations DFT(B3PW91) on the reaction of (C5H5)(2)CeH, referred to as Cp2CeH, and CH3X show that the barrier for alpha-CH activation, resulting in formation of Cp2Ce(eta(2)-CH2X), proceeds with a relatively low activation barrier (Delta G(double dagger)), but the subsequent ejection of CH2 and trapping by H-2 has a higher barrier; the height of the second barrier lies in the order F, Cl, Br, I < OMe << NMe2, consistent with the experimental studies. The DFT calculations also show that the two-step reaction, which proceeds through a carbenoid intermediate, has a lower barrier than a direct one-step or-bond metathesis mechanism. The reaction of Cp2CeCH2OMe and BPh3 is calculated to be a low-activation barrier process, and the ylide, CH2(+)BPh3(-1), is a transition state and not an intermediate.

  DOI：

  10.1021/om9001846
• 作为产物：
  描述：

  甲醚 、 bis(1,2,4-tri-tert-butylcyclopentadienyl)cerium hydride 以 正戊烷 为溶剂， 以37%的产率得到[(1,2,4-tri-tert-butylcyclopentadienyl)2Ce(η2-methoxymethylene)]
  参考文献：
  名称：

  Hydrogen for X-Group Exchange in CH₃X (X = Cl, Br, I, OMe, and NMe₂) by Monomeric [1,2,4-(Me₃C)₃C₅H₂]₂CeH: Experimental and Computational Support for a Carbenoid Mechanism

  摘要：

  The reactions between [1,2,4-(Me3C)(3)C5H2](2)CeH, referred to as Cp'2CeH, and CH3X, where X is Cl, Br, I, OMe, and NMe2, are described. The reactions fall into three distinct classes. Class a, where X = Cl, Br, and I, rapidly form Cp'2CeX and CH4 without formation of identifiable intermediates in the H-1 NMR spectra. Class b, where X = Me, proceeds rapidly to CP'Ce-2(eta(2)-CH2OMe) and H-2 and then to CP'2CeOMe and CH4. The methoxymethyl derivative is sufficiently stable to be isolated and characterized, and it is rapidly converted to Cp'2CeOMe in the presence of BPh3. Class c, where X = NMe2, does not result in formation of Cp'2CeNMe2, but deuterium labeling experiments show that H for D exchange occurs in NMe3. Density functional calculations DFT(B3PW91) on the reaction of (C5H5)(2)CeH, referred to as Cp2CeH, and CH3X show that the barrier for alpha-CH activation, resulting in formation of Cp2Ce(eta(2)-CH2X), proceeds with a relatively low activation barrier (Delta G(double dagger)), but the subsequent ejection of CH2 and trapping by H-2 has a higher barrier; the height of the second barrier lies in the order F, Cl, Br, I < OMe << NMe2, consistent with the experimental studies. The DFT calculations also show that the two-step reaction, which proceeds through a carbenoid intermediate, has a lower barrier than a direct one-step or-bond metathesis mechanism. The reaction of Cp2CeCH2OMe and BPh3 is calculated to be a low-activation barrier process, and the ylide, CH2(+)BPh3(-1), is a transition state and not an intermediate.

  DOI：

  10.1021/om9001846