bis(1,2,4-tri-tert-butylcyclopentadienyl)cerium OSO2CF3 | 832076-17-2

• 分子结构分类: 有机化合物 - 苯类化合物 - 苯和取代衍生物
• 英文名称: bis(1,2,4-tri-tert-butylcyclopentadienyl)cerium OSO2CF3
• 英文别名: cerium(3+);1,3,5-tritert-butylcyclopenta-1,3-diene;2,3,5-tritert-butylcyclopenta-1,3-diene;trifluoromethanesulfonate
• CAS: 832076-17-2
• 化学式: C₃₅H₅₈CeF₃O₃S
• 分子量: 756.025
• InChiKey: MTBJDTVARCUKNI-UHFFFAOYSA-M

计算性质

• 辛醇/水分配系数(LogP)：
  10.65
• 重原子数：
  43
• 可旋转键数：
  6
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.71
• 拓扑面积：
  65.6
• 氢给体数：
  0
• 氢受体数：
  8

反应信息

• 作为反应物：
  描述：

  bis(1,2,4-tri-tert-butylcyclopentadienyl)cerium OSO2CF3 、 甲基锂 以 乙醚 为溶剂， 生成 bis(1,2,4-tri-tert-butylcyclopentadienyl)cerium CH3 、 [1,2,4-(Me3C)3C5H2][(Me3C)2C5H2C(Me)2CH2]Ce
  参考文献：
  名称：

  Hydrogen for Fluorine Exchange in CH_4-xF_x by Monomeric [1,2,4-(Me₃C)₃C₅H₂]₂CeH:  Experimental and Computational Studies

  摘要：

  The monomeric metallocenecerium hydride, CP'(CeH (Cp' = 1,2,4-tri-tert-butylcyclopentadienyl), reacts instantaneously with CH)(F, but slower with CH)(F)(, to give CP')(CeF and CH)(2)(3)(2)(2)(2)(4) (in each case, a net H for F exchange reaction. The hydride reacts very slowly with CHF)(, and not at all with CF)(, to give CP'2CeF, H)(, and 1,2,4- and 1,3,5-tri-tert-butylbenzene. The substituted benzenes are postulated to result from trapping of a fluorocarbene fragment derived by a-fluoride abstraction from Cp')(CeCF)(. The fluoroalkyl, Cp')(CeCF)(, is generated by reaction of CP')(CeH and Me)(SiCF)(3)(4)(2)(2)(3)(2)(3)(2)(3)(3) (or by reaction of the metallacycle, [(Cp')(Me)(C))(C)(H)(C(Me)()CH)(]Ce, with CHF)(, and its existence is inferred from the products of decomposition, which are Cp)(CeF, the isomeric tri-tert-butylbenzenes and in the case of Me)(SiCF)(, Me)(SiH. The fluoroalkyls, CP')(CeCH)(F and CP')(CeCHF)(, generated from the metallacycle and CH)(F and CH)(F)(, respectively, are also inferred by their decomposition products, which are CP')(CeF, CH)(, and CHF, respectively, which are trapped. DFT(B3PW91) calculations have been carried out to examine several reaction paths that involve CH and CF bond activation. The calculations show that the CH activation by CP)(CeH proceeds with a low barrier. The carbene ejection and trapping by H)(3)(2)(5)(2)(2)(2)(3)(2)(3)(3)(3)(2)(2)(2)(2)(3)(2)(2)(2)(2)(2)(2) (is the rate-determining step, and the barrier parallels that found for reaction of H)(2) (with CH)(, CHF, and CF)(2)(2). The barrier of the rate-determining step is raised as the number of fluorines increases, while that of the CH activation path is lowered as the number of fluorines increases, which parallels the acidity.

  DOI：

  10.1021/ja0504800
• 作为产物：
  描述：

  [1,2,4-(Me3C)3C5H2]2Ce(18)OMe 、 三氟甲烷磺酸甲酯 以 全氘代环己烷 为溶剂， 反应 120.0h， 生成 bis(1,2,4-tri-tert-butylcyclopentadienyl)cerium OSO2CF3
  参考文献：
  名称：

  Cleaving bonds in CH₃OSO₂CF₃with [1,2,4-(Me₃C)₃C₅H₂]₂CeH; an experimental and computational study

  摘要：

  这是一项关于金属茂镧系氢化物[1,2,4-(Me3C)3C5H2]2CeH与甲基三氟甲磺酸酯(CH3OSO2CF3)在20°C下的反应研究。主要发现如下： 1. 反应生成了双金属配合物，其中SO32-阴离子桥连两个金属茂片段，这在有机金属化学中是独特的。 2. 与CH3OSO2CH3相比，CH3OSO2CF3形成类似的产物，但反应速率更快。 3. 该双金属配合物在20°C时的1H NMR谱图显示流动性，低温谱图与固态观察到的构型一致。 4. DFT计算表明，CH3OSO2CF3与金属茂反应时，C-H键活化和直接CH3基团转移具有相似的活化能垒。 5. 这与CH3OSO2CH3的反应不同，后者倾向于在SCH3基团发生C-H键活化。 6. 有趣的是，CH3OSO2CH3和CH3OSO2CF3的C-O键断裂活化能垒相似，这表明传统观点可能过分强调了CF3基团的电子吸引能力对磺酸酯化学和物理性质的影响。 这个研究揭示了反应机理并不是简单的甲基转移，而是涉及更复杂的过程。

  DOI：

  10.1039/c2nj40624a

文献信息

• Two [1,2,4-(Me₃C)₃C₅H₂]₂CeH Molecules are Involved in Hydrogenation of Pyridine to Piperidine as Shown by Experiments and Computations
  作者：Lionel Perrin、Evan L. Werkema、Odile Eisenstein、Richard A. Andersen

  DOI：10.1021/ic500133y

  日期：2014.7.7

  Hydrogenation of pyridine to piperidine catalyzed by [1,2,4-(Me3C)(3)C5H2](2)CeH, abbreviated as Cp'2CeH or [Ce]'-H, is reported. The reaction proceeds from Cp'Ce-2(2-pyridyl), isolated from the reaction of pyridine with Cp(')2CeH, to Cp'Ce-2(4,5,6-trihydropyridyl), and then to Cp'Ce-2(piperidyl). The cycle is completed by the addition of pyridine, which generates Cp'Ce-2(2-pyridyl) and piperidine. The net reaction depends on the partial pressure of H-2 and temperature. The dependence of the rate on the H-2 pressure is associated with the formation of Cp'2CeH, which increases the rate of the first and/or second additions of H-2 but does not influence the rate of the third addition. Density functional theory calculations of several possible pathways are consistent with three steps, each of which are composed of two elementary reactions, (i) heterolytic activation of H-2 with a reasonably high energy,Delta G double dagger = 20.5 kcal mol(-1), on Cp'Ce-2(2-pyridyl), leading to Cp'2CeH(6-hydropyridyl), followed by an intramolecular hydride transfer with a lower activation energy, (ii) intermolecular addition of Cp'2CeH to the C-4=C-5 bond, followed by hydrogenolysis, giving Cp'Ce-2(4,5,6-trihydropyridyl) and regenerating Cp'2CeH, and (iii) a similar hydrogenation/hydrogenolysis sequence, yielding Cp'Ce-2(piperidyl). The calculations reveal that step ii can only occur in the presence of Cp'2CeH and that alternative intramolecular steps have considerably higher activation energies. The key point that emerges from these experimental and computational studies is that step ii involves two Cp'Ce-2 fragments, one to bind the 6-hydropyridyl ligand and the other to add to the C-4=C-6 double bond. In the presence of 112, this second step is intermolecular and catalytic. The cycle is completed by reaction with pyridine to yield Cp'Ce-2(2-pyridyl) and piperidine. The structures of Cp'2CeX, where X = 2-pyridyl, 4,5,6-trihydropyridyl, and piperidyl, are fluxional, as shown by variable-temperature H-1 NMR spectroscopy.