【摘要】 采用自然键轨道理论(NBO)分析了吡啶甲酸铑阳离子催化剂([LRh(CO)2]+,L:吡啶甲酸配体)的结构和成键,结合前期研究工作结论,对催化剂从结构上进行了改进,设计了吡啶乙酸铑阳离子催化剂([LCH2-Rh(CO)2]+,LCH2:吡啶乙酸配体),采用从头算HF方法,在LANL2DZ基组下,优化得到了[LCH2-Rh(CO)2]+催化甲醇羰基化制备乙酸反应的决速步骤(CH3I氧化加成)反应物、产物、中间体、过渡态的构型,对反应每一驻点作了零点能(zero-pointenergy,ZPE)校正,计算了反应位垒(130.02kJ/mol),对比[LRh(CO)2]+催化剂,从构型、电荷分布、前线轨道等方面,探讨了吡啶乙酸铑阳离子催化剂具有高活性的本质原因,结果表明[LCH2-Rh(CO)2]+比[LRh(CO)2]+反应活性更高,共轭结构的破坏和六元环的引入使[LCH2-Rh(CO)2]+能够协同CH3I氧化加成,一定程度上降低了反应位垒。更多还原

【Abstract】 The geometry and bond of pyridine carbonylic acid rhodium cation(+,L:pyridine carbonylic acid ligand) have been analyzed for carbonylation of methanol to acetic acid through Nature Bond Orbit(NBO) theory.Above previous research,the geometry of + has been improved on and designed in molecule level.Next,density functional theory(DFT) and ab initio Hartree-Fock(HF) have been performed on rate-determining step of carbonylation of methanol which is catalyzed by +.All structural geometries of reactant,intermediates,transition states and product,respectively,are optimized at in the HF/LANL2DZ level.The energy of station points are improved by zero-point-energy(ZPE) correction,and the reaction activation barrier is 87.92 kJ/mol.Finally,by analyzing molecule obit,Mulliken atom charge and geometry,the substantial reasons of higher activity of + catalyst have been researched.The results indicate that + is better catalytic active than +,and the breakage of delocalization π bond and the characteristic of the 6-membered ring are reasons in nature.更多还原