Fe配合物催化的乙醛氢化反应机制的理论研究

Theoretical Study on Reaction Mechanism of Hydrogenation of Aldehyde Catalyzed by Iron Complex

利用Gaussian 03程序对Fe配合物催化的乙醛氢化反应机制进行了理论研究。此氢化反应包括两个过程:氢转移过程和氢活化过程。对于氢活化过程,本文根据是否需要乙醇的协助提出了两种反应路径:路径1是Fe的配合物单独与H2进行加成反应,路径2是Fe配合物在乙醇的协助下与H2进行加成反应。利用密度泛函理论对反应历程中所涉及到所有反应物、过渡态和产物的基态进行优化,并利用Gaussian 03程序中的NBO关键字对优化得到的反应物、过渡态和产物的构型进行了NPA电荷分析。通过比较反应能垒得到路径2是比较容易发生的反应,并得出在Fe配合物催化氢化乙醛的反应循环中,氢转移过程为决速步的结论。

The reaction mechanism of hydrogenation of aldehyde catalyzed by iron complex was studied with the Gaussian 03 program package. The hydrogenation reaction includes two processes： hydrogen transfer process and dihydrogen activation process. The dihydrogen activation process may proceed via two paths without （path 1 ） or with （ path 2） the assistance of alcohol. Geometric structures of all the reactants, transition states and products involved in the reaction process were optimized with the density functional theory. The natural population analysis was performed with NBO version 3.1 incorporated in the Gaussian 03 package. Through the analysis on 2 is favorable and the hydrogen transfer process is the energy barrier, we come to the conclusion that path the rate - determining step in the whole catalytic cycle.