CAJ | 학술논문

采用密度泛函理论方法，模拟了 Rh(PPh3)3 Cl 催化的 C-H 键活化/ C-C 键偶联反应.将反应机理分为 C-H 键活化、迁移插入和还原消除3个过程进行讨论.计算结果表明，势能面的最高点为迁移插入的过渡态，相对于初始原料的自由能为108.3 kJ/ mol.为了探索简化计算模型对模拟反应机理的影响，使用2种模型催化剂 Rh(PMe3)3 Cl 和 Rh(PH3)3 Cl 表征相同的反应过程，结果表明配体简化模型不合理，主要是因为 PPh3配体的空间效应和熵效应非常明显.
채용밀도범함이론방법，모의료 Rh(PPh3)3 Cl 최화적 C-H 건활화/ C-C 건우련반응.장반응궤리분위 C-H 건활화、천이삽입화환원소제3개과정진행토론.계산결과표명，세능면적최고점위천이삽입적과도태，상대우초시원료적자유능위108.3 kJ/ mol.위료탐색간화계산모형대모의반응궤리적영향，사용2충모형최화제 Rh(PMe3)3 Cl 화 Rh(PH3)3 Cl 표정상동적반응과정，결과표명배체간화모형불합리，주요시인위 PPh3배체적공간효응화적효응비상명현.
Density functional theory method was employed to simulate a Rh(PPh3 ) 3 Cl catalyzed C-H activa-tion / C-C cross-coupling reaction, in which three typical processes, namely, C-H activation, migratory in-sertion and reductive elimination, were characterized. The obtained results show that the rate-determining step is migratory insertion with the free-energy barrier of 108. 3 kJ/ mol. In order to test the validation of truncated models, two small catalysts Rh(PMe3 ) 3 Cl and Rh(PH3 ) 3 Cl were also used to study the same coupling reac-tion. Our calculations suggested that truncated models led to misunderstanding of reaction mechanism and free-energy changes, especially for migratory insertion process, since the steric effect and entropic contribution play a great role on these types of reactions.