The Mechanism of Methoxy Radical Oxidation by O2 in the Gas Phase. Computational Evidence for Direct H Atom Transfer Assisted by an Intermolecular Noncovalent O···O Bonding Interaction
The Mechanism of Methoxy Radical Oxidation by O2 in the Gas Phase. Computational Evidence for Direct H Atom Transfer Assisted by an Intermolecular Noncovalent O···O Bonding Interaction
复制标题
DOI：
10.1021/ja981926y
复制
发表时间：
1999-01
影响因子：
15
通讯作者：
J. M. Bofill;S. Olivella;A. Solé;J. Anglada
中科院分区：
文献类型：
--
作者：
J. M. Bofill;S. Olivella;A. Solé;J. Anglada
通过使用高级量子力学电子结构计算，研究了气相中CH3O• + O2 反应生成CH2O + HO2• 的机理。采用6-311G(d,p)基组的CASSCF方法对基态势能反应面上的15个驻点进行几何优化并计算其简谐振动频率。这些驻点通过使用 6-31G(d) 和 6-311G(d,p) 基组的 CISD 和 QCISD 方法通过后续几何优化和振动频率计算得到确认。相对能量是在 CCSD(T) 理论水平上计算的，扩展基础设置为 CASSCF/6-311G(d,p) 优化几何结构下的 cc-pVTZ。与最近的理论研究预测形成三氧基CH3OOO• 作为中间体的加成/消除机制相反，发现CH3O• 被O2 氧化是通过Cs 对称的环状过渡结构通过直接H 原子转移机制发生的。那个...
The mechanism of the CH3O• + O2 reaction in the gas phase leading to CH2O + HO2• was studied by using high-level quantum mechanical electronic structure calculations. The CASSCF method with the 6-311G(d,p) basis set was employed for geometry optimization of 15 stationary points on the ground-state potential energy reaction surface and computing their harmonic vibrational frequencies. These stationary points were confirmed by subsequent geometry optimizations and vibrational frequencies calculations by using the CISD and QCISD methods with the 6-31G(d) and 6-311G(d,p) basis sets. Relative energies were calculated at the CCSD(T) level of theory with extended basis sets up to cc-pVTZ at the CASSCF/6-311G(d,p)-optimized geometries. In contrast to a recent theoretical study predicting an addition/elimination mechanism forming the trioxy radical CH3OOO• as intermediate, the oxidation of CH3O• by O2 is found to occur by a direct H atom transfer mechanism through a ringlike transition structure of Cs symmetry. Th...