Does NHC Directly Participate in the CO2 Insertion into the U(Ⅲ)-N Bond? A Density Functional Theory

• 作 者: WanjianDing[1]DongqiWang[2]YanxiaoLiu[1]
• 机 构: Key Laboratory of Theoretical and Computational Photochemistry,Ministry of Education,College of Chem
• 出 处: 第十二届全国量子化学会议
• 发表日期: 2014年期

　　The mechanisms of CO2 insertion into the U(Ⅲ)-N bond of M(LD)N”2(LD=2,6-iPr2-C6H3,N”=N(SiMe3)2)were investigated employing Gaussian09 package with B3PW91 functional of density functional theory.The results support a three-step mechanism that CO2 inserts into the U(Ⅲ)-N bond directly,followed by SiMe3 migration and C-O bond broken to obtain the U(Ⅳ)complex.The reaction is thermodynamically favorable by 35.0 kcal/mol,and the free energy barrier to the rate-determining step is calculated to be 17.7 kcal/mol in vacuum and 18.in benzene.Another mechanism proposed by Arnold was also investigated in the present work,wher the free energy barrier to the rate-determinin stepwa estimated to be 72.0 kcal/mol,which is inhibitive under the experimental condition,thus less possible compared to the three-step mechanism mentioned above.