Cp*非无辜性通过金属素质突变导致显著弱的C-H键
Matthew J Chalkley1, Paul H Oyala1, Jonas C Peters1
1Division of Chemistry and Chemical Engineering , California Institute of Technology (Caltech) , Pasadena , California 91125 , United States.
Journal of the American Chemical Society
|February 22, 2019
概括
甲衍生物的质子化揭示了环质子化异构体,Cp*(exo/endo-η4-C5Me5H) Co+. 这项研究描述了这些物种及其异常弱的C-H键,这对于理解还原催化是至关重要的.
科学领域:
- 有机金属化学
- 催化剂
- 光谱学
背景情况:
- 金属在有机金属化学中至关重要,作为氧化剂或减少剂.
- 在像N2这样的小分子的还原性质子中,甲衍生物是有用的.
- 了解金属素与酸的行为对于催化应用至关重要.
研究的目的:
- 使用先进的光谱技术来描述Cp*2Co的质子化产物.
- 研究环质子化同体的形成和特性.
- 探索这些发现对催化固定和化物转移的影响.
主要方法:
- 使用低温脉冲电子磁共振 (EPR) 光谱.
- 使用可变温度的Q频段 (34 GHz) 脉冲EPR.
- 结合实验数据与密度函数理论 (DFT) 预测物种分配.
主要成果:
- 提供了Cp*(exo/endo-η4-C5Me5H) Co+异构体形成的明确证据.
- 证明较大的酸有利于外质子选择性.
- 实验确定了Cp*(exo-η4-C5Me5H) Co+ 的异常弱的C-H键解离自由能量 (<29 kcal mol-1).
结论:
- 描述的质子化类物种具有高度反应性,易发生化物转移.
- 外质子选择性受到酸的影响,这表明在催化固定中具有相关性.
- 开发了一种合理化质金属物种反应性的方法,适用于其他系统,如十甲基尼基洛.
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