化学
催化作用
吉布斯自由能
催化循环
四氢呋喃
电泳剂
溴化物
密度泛函理论
溶剂
齿合度
药物化学
计算化学
结晶学
有机化学
热力学
晶体结构
物理
作者
Xin Wan,Ting Zhao,Qinghua Ren,Gangchang Zhou
出处
期刊:Organometallics
[American Chemical Society]
日期:2024-02-15
卷期号:43 (4): 449-456
标识
DOI:10.1021/acs.organomet.3c00391
摘要
Density functional theory studies for the role of N,N,N′,N′-tetramethylethylenediamine (TMEDA) in iron-catalyzed cross-coupling reactions between phenylmagnesium bromide and bromocycloheptane have been investigated using B3LYP-D3BJ functionals and the SMD (tetrahydrofuran) model. The results reveal that the whole catalytic cycle has two possible pathways: one in which main product P1, named Path A, is obtained or another in which byproduct P2, named Path B, is obtained. TMEDA-bound iron intermediates are responsible for the products of P1 or P2. The radical intermediate initiated by TMEDA–iron species starts the reaction, which just highlights the central role of TMEDA intermediates in the catalytic cycle. Different spin states of the iron species are checked. The calculated results are helpful for understanding the mechanisms of TMEDA involved in iron-catalyzed cross-coupling reactions. It shows that the rate-determining step to obtain main product P1 in Path A is a reductive elimination step where Gibbs free energy in solvent THF, ΔGsol, is 9.5 kcal/mol, and the rate-limiting step to obtain byproduct P2 in Path B is the radical initiation step where Gibbs free energy in solvent THF, ΔGsol, is 26.4 kcal/mol, which means that Path A to obtain main product P1 is favored, which meets the experimental results.
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