Computational study of the threshold energy for the 1,2-interchange of X and R (X, R = halogens, pseudohalogens, and monovalent hydrocarbon groups) on CH2XCH2R
Computational study of the threshold energy for the 1,2-interchange of X and R (X, R = halogens, pseudohalogens, and monovalent hydrocarbon groups) on CH2XCH2R
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CH2XCH2R 上 X 和 R（X、R = 卤素、拟卤素和单价烃基）1,2-交换阈值能量的计算研究
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
B. E. Holmes
中科院分区：
文献类型：
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作者：
Ju;Laura M. Brandt;G. L. Heard;B. E. Holmes
计算了一个不寻常的单分子异构化反应的过渡态几何构型和阈值能量E0，该反应在CH 2XCH 2 R上交换两个基团（X，R）。一个目标是确定最积极可行的立交桥，以指导实验研究。可互换的物种包括卤素（F、Cl、Br）和拟卤素以及连接到两个碳主链上的单价烃（H、SH、CH 3、NH 2、OH、OCF 3、OCH 3、CH= CH 2、CH 2CH 3、CH 2 OH、CH = CH、CH 2CF 3、CCl 3、CF 3）。在B3 PW 91水平下，采用6-311+G（2d，p）基组优化了基态和过渡态的几何构型. Br-Br交换的E0最低（141 kJ/mol），CH 3-H的E0最高（582 kJ/mol）。一般来说，具有孤对电子的较大原子或基团，例如卤素、SH、OH、OCH 3、OCF 3和NH 2，往往会降低交换的E0势垒，使它们最有可能在实验中观察到。
Transition state geometries and threshold energies, E0, were computed for an unusual unimolecular isomerization reaction that exchanges two groups (X, R) on CH2XCH2R. An objective is to determine the most energetically feasible interchanges to guide experimental investigations. The interchanging species included halogens (F, Cl, Br) and pseudohalogens and monovalent hydrocarbons (H, SH, CH3, NH2, OH, OCF3, OCH3, CH=CH2, CH2CH3, CH2OH, C≡CH, CH2CF3, CCl3, CF3) attached to a two carbon backbone. Ground state and transition state geometries were optimized with the B3PW91 level of theory and 6-311+G(2d,p) basis set. The Br–Br interchange had the lowest E0 (141 kJ/mol), and CH3–H had the highest E0 (582 kJ/mol). In general, larger atoms or groups with lone pairs of electrons such as halogens, SH, OH, OCH3, OCF3, and NH2 tend to lower the E0 barrier for interchange, making them the most likely to be experimentally observed.