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化学学报
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化学学报 ›› 2009, Vol. 67 ›› Issue (12): 1303-1310. 上一篇    下一篇

研究论文

杂双核Rh(I)-Cr配合物催化乙炔氢甲酰化反应机理的密度泛函研究

唐典勇*,a 胡常伟b

  

  1. (a乐山师范学院化学与生命科学学院 乐山 614000)
    (b四川大学化学学院 成都 610064)

  • 投稿日期:2008-10-07 修回日期:2008-12-15 发布日期:2009-06-28
  • 通讯作者: 唐典勇

DFT Study on Mechanism of Acetylene Hydroformylation Catalyzed by Heterobinuclear Rh(I)-Cr Complex

Tang, Dianyong *,a Hu, Changwei b

  

  1. (a College of Chemistry and Life Science, Leshan Teacher’s College, Leshan 614000)
    (b College of Chemistry, Sichuan University, Chengdu 610064)
  • Received:2008-10-07 Revised:2008-12-15 Published:2009-06-28
  • Contact: TANG Dian-Yong

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被引次数

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用密度泛函B3LYP方法对杂双核(CO)4Cr(μ-PH2)2RhH(CO)(PH3)配合物催化乙炔氢甲酰化反应机理进行了详细研究. 对结合和解离机理所涉及中间体和过渡态的结构进行详细分析, 在此基础上阐明了金属铬的协同性. 计算结果表明解离机理占主导地位. 乙炔氢甲酰化反应的决速步骤为炔烃插入步骤, 在298.15 K和101.325 kPa下的活化自由能为73.72 kJ/mol. 乙炔插入和醛还原消除步骤均在热力学上不可逆. Cr(CO)4部分的引入并没有改变乙炔氢甲酰化反应机理. Rh与Cr间的d轨道相互作用在反应过程起重要作用.

关键词: 杂双核Rh(I)-Cr配合物, 乙炔, 氢甲酰化反应, 反应机理, 密度泛函理论

Theoretical study on the mechanism of acetylene hydroformylation catalyzed by a heterobinuclear (CO)4Cr(m-PH2)2RhH(CO)(PH3) complex has been carried out in the framework of density functional theory. Structural features of intermediates and transition states of the associative and dissociative mechanisms and the cooperativity of chromium with rhodium were evaluated. It was found that the dissociative mechanism was predominant. The rate-limiting step is the acetylene insertion step with a free energy barrier of 73.72 kJ/mol at 298.15 K and 101.325 kPa. The acetylene insertion and aldehyde elimination steps are irreversible thermodynamically. The introduction of Cr(CO)4 moiety does not alter the mechanism of acetylene hydroformylation. The orbital interaction between Rh and Cr atoms plays an important role in the whole reaction process.

Key words: heterobinuclear Rh(I)-Cr complex, acetylene, hydroformylation, mechanism, density functional theory