Nature of the transition structure for alkene epoxidation by peroxyformic acid, dioxirane, and dimethyldioxirane: A comparison of B3LYP density functional theory with higher computational levels
Nature of the transition structure for alkene epoxidation by peroxyformic acid, dioxirane, and dimethyldioxirane: A comparison of B3LYP density functional theory with higher computational levels
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DOI：
10.1021/jp970378s
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发表时间：
1997-08-21
影响因子：
2.9
通讯作者：
Schlegel, HB
中科院分区：
文献类型：
--
作者：
Bach, RD;Glukhovtsev, MN;Schlegel, HB
研究了乙烯、丙烯、顺式和反式-2-丁烯与过氧甲酸以及乙烯与二环氧乙烷和二甲基二环氧乙烷的环氧化反应的密度泛函B3 LYP计算性能。在B3 LYP水平以及QCISD和CCSD水平上计算的乙烯和丙烯与过氧甲酸环氧化以及乙烯与二环氧乙烷和二甲基二环氧乙烷环氧化的过渡结构是对称的，具有几乎相同的C-O键距，而MP2计算有利于不对称的过渡结构。用B3 LYP方法计算得到的跃迁结构的几何参数与QCISD和CCSD水平上的结果接近。虽然在B3 LYP/6- 31 G * 和B3 LYP/6-31+G* 水平上计算的环氧化反应的活化能垒非常接近MP4 SDTQ/6- 31 G *//MP2/6- 31 G * 和MP2/6- 31 G *//MP2/6- 31 G * 值，这些活化能系统地较低，（高达5-6 kcal/mol）的势垒高度比在更高的相关水平下计算的势垒高度高，如QCISD（T）/6- 31 G *//QCISD/6- 31 G *，CCSD（T）/6- 31 G *//CCSD/6- 31 G *，和BD（T）/6-31G*//QCISD/6-31G*。用BH&HLYP泛函对乙烯和丙烯与过氧甲酸的环氧化反应进行了计算，也得到了对称的过渡结构，但与QCISD（T）结果相比，计算的势垒被高估了。在QCISD（T）/6- 31 G *//B3 LYP/6- 31 G * 水平上计算的环氧化反应的活化能垒与在QCISD（T）/6- 31 C *//QCISD/6- 31 G * 水平上计算的活化能垒非常接近。
The performance of the B3LYP density functional theory calculations has been studied for the epoxidation reactions of ethylene, propene, and cis-and trans-2-butene with peroxyformic acid and of ethylene with dioxirane and dimethyldioxirane. The transition structures for the epoxidation of ethylene and propene with peroxyformic acid and of ethylene with dioxirane and dimethyldioxirane calculated at the B3LYP level as well as at the QCISD and CCSD levels are symmetrical with nearly identical C-O bond distances, whereas the MP2 calculations favor unsymmetrical transition structures. The geometrical parameters of the transition structures calculated using the B3LYP functional are close to those found at the QCISD and CCSD levels. While the activation barriers for the epoxidation reactions calculated at the B3LYP/6-31G* and B3LYP/6-31+G* levels are very close to the MP4SDTQ/6-31G*//MP2/6-31G* and MP2/6-31G*//MP2/6-31G* values, these activation energies are systematically lower (up to 5-6 kcal/mol) than the barrier heights calculated at such higher correlated levels as the QCISD(T)/6-31G*//QCISD/6-31G*, CCSD(T)/6-31G*//CCSD/6-31G*, and BD(T)/6-31G*//QCISD/6-31G*. The calculations on the epoxidation reactions of ethylene and propene with peroxyformic acid using the BH&HLYP functional also lead to symmetrical transition structures, but the calculated barriers are overestimated when compared with the QCISD(T) results. The activation barriers calculated for these epoxidation reactions at the QCISD(T)/6-31G*//B3LYP/6-31G* level are very close to those computed at the QCISD(T)/6-31C*//QCISD/6-31G* level.