| Gas-phase non-identity S(N)2 reactions at neutral nitrogen: a hybrid DFT study |
| Yang, J
; Ren, Y
; Zhu, HJ
; Chu, SY
|
| 通讯作者 | Ren, Y (reprint author), Sichuan Univ, Fac Chem, Chengdu 610064, Peoples R China.
|
| 2003
|
| 发表期刊 | INTERNATIONAL JOURNAL OF MASS SPECTROMETRY
 |
| ISSN | 1387-3806
|
| 卷号 | 229期号:3页码:199-208 |
| 摘要 | The gas-phase non-identity nucleophilic substitution reactions at saturated nitrogen Y-+ NH2X --> NH2Y + X- (Y, X = F, Cl, Br and I) were evaluated at the level of MPW1K/6-31+G(d, p). The enthalpies of reactions are exothermic only when the nucleophile is the lighter halide. Central barriers (DeltaH(YX)(not equal)) for reactions in the exothermic direction are slightly higher than the corresponding barriers at carbon. The lower overall barriers relative to the reactants (DeltaH(YX)(b)) than the corresponding reactions at carbon suggest that S(N)2 reactions at nitrogen may be more facile than at carbon. Both the central barriers (AH(YX)(not equal)) and the overall barriers (DeltaH(YX)(b)) correlate well with reaction exothermicity. Further interesting features of the non-identity reactions at nitrogen are the reasonable correlation between the central barriers (DeltaH(YX)(not equal)) with the composite geometrical looseness (%L-not equal), geometrical asymmetry (%AS(not equal)), and charge asymmetry of the transition structures (Deltaq (X - Y)). The data for the central barriers and the overall barriers show good agreement with the prediction of the Marcus equation and its modification, respectively. Kinetic and thermodynamic investigations predict that the nucleophilicity of X- in the S(N)2 at nitrogen decreases in the order F- < Cl- < Br- < I-, the leaving-group ability increases in the order F > Cl > Br > I. (C) 2003 Elsevier B.V. All rights reserved. |
| 关键词 | s(n)2 At Neutral Nitrogen
Hybrid Dft Method
Reaction Mechanism
Nucleophilicity
Transition-state Geometries
Nucleophilic-substitution
Methyl Halides
Sn2 Reactions
Anions
Displacement
Barriers
|
| 学科领域 | Physics, Atomic, Molecular & Chemical
; Spectroscopy
|
| 收录类别 | sci
|
| 语种 | 英语
|
| 文献类型 | 期刊论文
|
| 条目标识符 | http://ir.kib.ac.cn/handle/151853/15462
|
| 专题 | 植物化学与西部植物资源持续利用国家重点实验室
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推荐引用方式
GB/T 7714 |
Yang, J,Ren, Y,Zhu, HJ,et al. Gas-phase non-identity S(N)2 reactions at neutral nitrogen: a hybrid DFT study[J]. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY,2003,229(3):199-208.
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| APA |
Yang, J,Ren, Y,Zhu, HJ,&Chu, SY.(2003).Gas-phase non-identity S(N)2 reactions at neutral nitrogen: a hybrid DFT study.INTERNATIONAL JOURNAL OF MASS SPECTROMETRY,229(3),199-208.
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| MLA |
Yang, J,et al."Gas-phase non-identity S(N)2 reactions at neutral nitrogen: a hybrid DFT study".INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 229.3(2003):199-208.
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