MOLECULAR MODELING OF THE KINETIC ISOTOPE EFFECT FOR THE [1,5] SIGMATROPIC REARRANGEMENT OF CIS-1,3-PENTADIENE
MOLECULAR MODELING OF THE KINETIC ISOTOPE EFFECT FOR THE [1,5] SIGMATROPIC REARRANGEMENT OF CIS-1,3-PENTADIENE
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DOI：
10.1021/ja00059a041
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发表时间：
1993-03-24
影响因子：
15
通讯作者：
GARRETT, BC
中科院分区：
文献类型：
--
作者：
LIU, YP;LYNCH, GC;GARRETT, BC
用直接动力学方法研究了顺式-1，3-戊二烯[1，5] σ迁移重排反应的动力学同位素效应。计算是使用计算机代码MORATE进行的，该代码结合了半经验分子轨道包MOPAC和我们研究小组之前开发的多原子动力学代码POLYRATE。动力学计算是基于正则变分过渡态理论，包括多维隧道校正。力场是由分子轨道理论与AM 1，PM 3和MINDO/3参数化。用MINDO/3和PM 3哈密顿量计算的动力学同位素效应与AM 1的计算值在13%以内符合，AM 1的计算值与实验值在13%以内符合。分析了隧穿效应对动力学同位素效应的贡献，讨论了振动辅助隧穿过程的本质。从所有三个参数化的动力学的一般特征是相似的，和定量的差异，在三个计算的预测可以理解的全球性特征的势能函数，他们预测。
The primary kinetic isotope effect for the [1,5] sigmatropic rearrangement reaction of cis-1,3-pentadiene is studied by the direct dynamics method. The calculations are carried out with the computer code MORATE, which combines the semiempirical molecular orbital package, MOPAC, and the polyatomic dynamics code, POLYRATE, developed previously by our research group. Dynamics calculations are based on canonical variational transition-state theory including multidimensional tunneling corrections. The force field is obtained by molecular orbital theory with the AM1, PM3, and MINDO/3 parameterizations. The kinetic isotope effects calculated with the MINDO/3 and PM3 Hamiltonians agree with those calculated by AM1 within 13%, and the latter agree with experiment within 13%. The tunneling contributions to the kinetic isotope effects are analyzed, and the nature of the vibrationally assisted tunneling process is discussed. General features of the dynamics from all three parameterizations are similar, and the quantitative differences in the predictions of the three calculations can be understood in terms of global characteristics of the potential energy functions that they predict.