用Ru,Rh和Ir复合物催化的甲玻里化与循环玻里化相比:理论理解和预测
Rong-Lin Zhong1, Shigeyoshi Sakaki2
1Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, P. R. China.
本研究使用DFT探索甲玻利化,揭示Cp*Ru(Bpin) 3作为活性物种,并确定关键中间体. 该研究详细介绍了不同金属催化剂对甲的催化活性和选择性.
科学领域:
- 有机金属化学
- 催化剂
- 计算化学
背景情况:
- 甲化是利用C-H键的关键转化.
- 了解反应机制是设计高效催化剂的关键.
- 在此之前对Ru催化玻利的理论研究是有限的.
研究的目的:
- 使用 DFT 阐明由 Cp*M(Bpin) n (M = Ru, Rh) 和 (TMPhen) Ir(Bpin) 3 催化的甲化反应机制.
- 将这些系统的催化活性和选择性与甲和环乙化进行比较.
- 通过计算提出改进的连接体设计,以增强Ir催化甲化.
主要方法:
- 用密度函数理论 (DFT) 的计算来研究反应途径.
- 对关键中间体,过渡状态和结合相互作用 (例如H·Bpin) 进行了分析.
- 对速率决定步骤的激活能量进行了比较.
主要成果:
- Cp*Ru(Bpin) 3被确定为Ru-催化甲化中的活性物种,其中Cp*Ru(Bpin) 3 ((H) ((CH3) 是具有独特H·Bpin相互作用的关键中间体.
- 甲化的催化活性按照以下顺序进行:Cp*Ru(Bpin) 3 < (TMPhen) Ir(Bpin) 3 < Cp*Rh(Bpin) 2.
- 对甲的化学选择性比环素增加了Ir < Ru < Rh的顺序,归因于速度决定阶段的硬质因子.
结论:
- 在所有研究的催化剂中,甲的化是通过氧化添加和还原性消除进行的.
- 在决定速率的步骤和化学选择性中,固体阻碍起着重要作用,特别是在环乙化过程中.
- 计算设计表明,在Ir催化剂上具有庞大的替代体的电子捐赠配体可以改善甲化活性和化学选择性.
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