【摘要】 使用B3LYP方法研究了三线态Salen-Mn(V)氧化物1催化氧化烯烃CH2=CHR(R=H,Me,Ph)的环氧化反应中不同取代基对反应势垒的影响.优化得到了相关反应物、中间体、过渡态和环氧化产物即环氧烷烃和Salen-Mn(Ⅲ)复合物的结构.计算了三线态各驻点上吉布斯自由能值.研究结果显示,所有反应均为放热反应,反应势垒都很小,说明这些反应在室温下都很容易发生;当R=Me时,反应的活化吉布斯自由能最低,当R=H时,反应的活化吉布斯自由能最高.更多还原

【Abstract】 B3LYP density functional calculations were carried out to study the epoxidation of substituted ethylene CH2=CHR(R=H,Me,Ph), where a model catalyst with chloride as oxygen containing counter ligand, MnSalen(O)(Cl), was employed. The optimal structures of the reactants, intermediates, transition states, and products were obtained. The Gibbs free energies were calculated and the effects of the substituents on the barriers was therefore illustrated. Calculations results show that all three reactions are exothermic, and reaction barriers are small, so all the reactions will steadily take place at the room temperature. The activation free energy is smallest for R=Me, while it is largest for R=H.更多还原