[(1,2,4-tri-tert-butylcyclopentadienyl)2Ce(OMe)] | 932029-03-3

• 英文名称: [(1,2,4-tri-tert-butylcyclopentadienyl)2Ce(OMe)]
• 英文别名: [(1,2,4-tri-tert-butylcyclopentadienyl)Ce(OMe)]；[(1,2,4-(Me3C)3C5H2)2Ce(OCH3)]；[1,2,4-(Me3C)3C5H2]2CeOMe
• CAS: 932029-03-3
• 化学式: C₃₅H₆₁CeO
• 分子量: 637.989
• InChiKey: LHSYTIKULUXWPZ-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：

  甲磺酸甲酯 、 [(1,2,4-tri-tert-butylcyclopentadienyl)2Ce(OMe)] 以 氘代苯 为溶剂， 生成 [(1,2,4-(Me3C)3C5H2)2Ce(OSO2CH3)]
  参考文献：
  名称：

  Selectivity in the C–H Activation Reaction of CH₃OSO₂CH₃ with [1,2,4-(Me₃C)₃C₅H₂]₂CeH or [1,2,4-(Me₃C)₃C₅H₂][1,2-(Me₃C)₂-4-(Me₂CCH₂)C₅H₂]Ce: To Choose or Not To Choose

  摘要：

  The experimental reaction of [1,2,4-(Me3C)(3)CsH2](2)CeH, Cp'2CeH, and CH3OSO2CH3 begins by alpha-C-H activation of the SCH3 group, forming CP'(2) CeCH2SO2(OCH3), which evolves into CP'2CeOCH3 with elimination of CH2 (and presumably SO2). Prolonged heating of this mixture (days at 60 degrees C) forms Cp'2CeOSO2CH3 and CH3OCH3. The metallacycle [1,2,4-(Me3C)(3)C5H2][1,2-(Me3C)(2)-4-(Me2CCH2)C3H2)Ce, when presented with the choice of C-H bonds in CH3S and CH3O groups, deprotonates both with comparable rates, ultimately forming Cp'(2) CeOCH3 and Cp'2CeOSO2CH3 at 20 degrees C. The experimental studies are illuminated by DFT calculations on the experimental systems, which show that the hydride selects the more acidic CH3S bond, whereas the metallacycle reacts with C-H bonds of both the CH3S and CH3O groups of CH3OSO2CH3. In the metallacycle reaction, the initially formed regioisomers, Cp'2CeCH2SO2(OCH3) and Cp'2CeCH2OSO2CH3, rearrange to the observed products, Cp'2CeOCH3 and Cp'2CeOSO2CH3, respectively, Furthermore, C-H activation at the SCH3 group forms two isomers of Cp'2CeCH2SO2(OCH3) in the reaction of CH3OSO2CH3 with the metallacycle and only one in the reaction with the hydride. The lack of selectivity in the reactions of the metallacycle relative to the hydride is due to the metallacycle's greater thermodynamic advantage and lower energy barriers, which are linked to the higher bond energy of Ce-H relative to Ce-C in the metallacycle.

  DOI：

  10.1021/om200842t
• 作为产物：
  描述：

  甲醚 、 bis(1,2,4-tri-tert-butylcyclopentadienyl)cerium hydride 以 全氘代环己烷 为溶剂， 生成 [(1,2,4-tri-tert-butylcyclopentadienyl)2Ce(OMe)]
  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

文献信息

• Reactions of Monomeric [1,2,4-(Me₃C)₃C₅H₂]₂CeH and CO with or without H₂:  An Experimental and Computational Study
  作者：Evan L. Werkema、Laurent Maron、Odile Eisenstein、Richard A. Andersen

  DOI：10.1021/ja066482h

  日期：2007.3.1

  Addition of CO to [1,2,4-(Me3C)3C5H2]2CeH, CeH, in toluene yields the cis-( Ce)2(μ-OCHCHO), in which the cis-enediolate group bridges the two metallocene fragments. The cis-enediolate quantitatively isomerizes intramolecularly to the trans-enediolate in C6D6 at 100 °C over 7 months. When the solvent is pentane, Ce(OCH2)Ce forms, in which the oxomethylene group or the formaldehyde dianion bridges the

  将 CO 添加到甲苯中的 [1,2,4-(Me3C)3C5H2]2CeH,CeH 中产生顺式-(Ce)2(μ-OCHCHO)，其中顺式烯二醇基团桥接两个茂金属片段。顺式烯二醇在 7 个月内在 100 °C 下在 C6D6 中定量异构化为反式烯二醇。当溶剂为戊烷时，会形成 Ce(OCH2)Ce，其中氧亚甲基或甲醛二价阴离子桥接两个茂金属片段。顺式烯二醇被认为是通过将 CO 插入 Ce(OCH2)Ce 的 Ce-C 键中形成的，生成 CeOCH2COCe。顺式烯二醇酯的立体化学由 OCH2CO 片段中的 1,2-氢位移决定，该片段具有相对于卡宾孤对的 OC(H2) 键反周面。桥接氧亚甲基络合物与 H2 反应，但不与 CH4 反应，得到 CeOMe，它也是 CeH 与 CO 和 H2 的混合物反应的产物。氧亚甲基络合物与 CO 反应生成顺式烯二醇络合物。C5H5 模型茂金属的 DFT 计算表明.
• Cleaving bonds in CH₃OSO₂CF₃with [1,2,4-(Me₃C)₃C₅H₂]₂CeH; an experimental and computational study
  作者：Evan L. Werkema、Ludovic Castro、Laurent Maron、Odile Eisenstein、Richard A. Andersen

  DOI：10.1039/c2nj40624a

  日期：——

  The reaction at 20 °C of the metallocenelanthanide hydride, [1,2,4-(Me3C)3C5H2]2CeH, , and excess methyltrifluoromethanesulfonate, CH3OSO2CF3, results in formation of , , and the bimetallic complex . The metallocenes , , and react with excess CH3OSO2CF3 to form , CH3OCH3, CH3F, and (CH3O)2SO, respectively, at 20 °C. Thus, the net reaction is but the pathway is not a direct methyl transfer. Comparison of the reactivity of CH3OSO2CF3 and CH3OSO2CH3 (Werkema et al., Organometallics, 2012, 31, 870) is revealing since both form a similar set of products but the rates of reaction of CH3OSO2CF3 are faster. The bimetallic complex, in which the SO32− anion bridges two fragments, is unique in organometallic chemistry. The 1H NMR spectrum is fluxional at 20 °C and the low temperature spectrum is consistent with the geometry observed in the solid state. Density Functional Theory (DFT) calculations of the Gibbs energy profiles for the reaction of CH3OSO2CF3 with show that the CH-bond activation and direct CH3 group transfer have similar activation energy barriers. This contrasts with what is observed in the reaction of with CH3OSO2CH3, where CH-bond activation at the SCH3 group is preferred. Remarkably, the activation energy barriers for C–O-bond cleavage are similar in CH3OSO2CH3 and CH3OSO2CF3, which is traced to the calculated small exoergicity of −1.7 kcal mol−1 for the reaction of . This contrasts, perhaps, with conventional wisdom that overemphasizes the effect of the electron-withdrawing ability of the CF3 group on the chemical and physical properties of sulfonate esters.

  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(CH3OSO2 )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 OSO2 相比， OSO2 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， OSO2 与金属茂反应时，C-H键活化和直接 基团转移具有相似的活化能垒。 5. 这与 OSO2 的反应不同，后者倾向于在S 基团发生C-H键活化。 6. 有趣的是， OSO2 和 OSO2 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。
• Bridging Silyl Groups in σ-Bond Metathesis and [1,2]-Shifts. Experimental and Computational Study of the Reaction between Cerium Metallocenes and MeOSiMe₃
  作者：Evan L. Werkema、Ahmed Yahia、Laurent Maron、Odile Eisenstein、Richard A. Andersen

  DOI：10.1021/om1003286

  日期：2010.11.8

  SiMe3 reactions have in common a pentacoordinate silicon at the transition states. A molecular orbital analysis illustrates the connection between these two Si−O bond cleavage reactions and traces the reason why they occur for a silyl but not for an alkyl group to the difference in energy required to form a pentacoordinate silicon or carbon atom in the transition state. This difference clearly distinguishes

  CP'的反应2 CEH（CP'= 1,2,4-（ME 3 C）3 c ^ 5 ħ 2）与MeOSiMe 3给出了CP' 2 CeOMe和HSiMe 3，以及金属环CP的反应'[（箱3 C）2 C ^ 5 ħ 2 C（Me）的2 CH 2 ]的Ce与MeOSiMe 3个产率CP' 2 CeOCH 2森达3，从假想的CP'形成2切克2 OSiMe 3通过[1,2]移位也称为甲硅烷基-维蒂希重排。尽管两种铈产物都是醇盐，但它们是通过不同的途径形成的。对模型金属茂CP 2 CeH和MeOSiMe 3反应的DFT计算表明，最低能量途径是H在Ce进行OMe交换的H，这是通过SiMe 3交换伙伴时通过σ键易位过渡态发生的。CP 2 CeOCH 2 SiMe 3的形成是通过CP 2 CeCH 2 OSiMe 3中SiMe 3基团的低活化势垒[1,2]位移发生的。模型金属环CP [C 5 H 4的计算C（Me）2