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化学学报
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化学学报 ›› 2008, Vol. 66 ›› Issue (22): 2483-2488. 上一篇    下一篇

研究论文

双取代铵氧化物(R2HNO)与双取代羟胺(R2NOH)的 相互转换机制的量子化学研究

石国升 丁益宏*

  

  1. (吉林大学理论化学研究所 理论化学计算国家重点实验室 长春 130023)

  • 投稿日期:2008-01-11 修回日期:2008-02-29 发布日期:2008-11-28
  • 通讯作者: 丁益宏

A Quantum Chemical Study on the Interconversion Mechanism between Double-substituted Ammonium Oxide and Double-substituted Hydroxylamine

SHI, Guo-Sheng DING, Yi-Hong*   

  1. (State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry,
    Jilin University, Changchun 130023)
  • Received:2008-01-11 Revised:2008-02-29 Published:2008-11-28
  • Contact: DING, Yi-Hong

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被引次数

4 | 3

在B3LYP/6-311＋＋G(d,p)水平下, 首次对一系列双取代铵氧化物(R2HNO)与双取代羟胺(R2NOH) [R＝CH3, NH2, OH, F, CH2CH3, CH(CH3)2, C(CH3)3]同分异构体的相互转换机制进行了理论计算研究, 并与已知的H3NO和H2NOH进行了比较. 结果表明, 相对于双取代羟胺(R2NOH), 按照H＜CH3＜NH2＜OH＜F的顺序, 增加取代基R的电负性有助于提高双取代铵氧化物(R2HNO)的热力学和动力学稳定性. 此外, 对烷基取代基R [R＝CH3, CH2CH3, CH(CH3)2, C(CH3)3], 其空间位阻越大越能增加双取代铵氧化物(R2HNO)的热力学稳定性, 动力学稳定性也有相应增加, 但不显著. 对所研究的7种取代基[R＝CH3, NH2, OH, F, CH2CH3, CH(CH3)2, C(CH3)3], R2HNO向R2NOH转换的能垒介于27.0～56.3 kcal/mol之间, 表明在气相条件下极有可能观测到双取代铵氧化物(R2HNO).

关键词: R2HNO, R2NOH, 同分异构体, 热力学稳定性, 动力学稳定性

At the B3LYP/6-311＋＋G(d,p) level, the first time computational study was performed on the interconversion mechanism between a series of double-substituted ammonium oxide (R2HNO) and double-substituted hydroxylamine (R2NOH) isomers with R＝CH3, NH2, OH, F, CH2CH3, CH(CH3)2 and C(CH3)3. Comparisons were made with the mechanism of H3NO and H2NOH. It was shown that relative to the double-substitued hydroxylamine (R2NOH), the increase of the electronegativity of R in the order of H＜CH3＜NH2＜OH＜F could raise both the thermodynamic and kinetic stability of the double-substituted ammonium oxide (R2HNO). In addition, for the alkyl substituents R [R＝CH3, CH2CH3, CH(CH3)2 and C(CH3)3], the greater steric effect would result in the higher thermodynamic stability, and also certainly increased kinetic stability, though not so noticeable. For the newly considered seven substituents [R＝CH3, NH2, OH, F, CH2CH3, CH(CH3)2 and C(CH3)3], the conversion barrier from R2HNO to R2NOH is as large as 27.0～56.3 kcal/mol. This indicates that all of them might be probably characterized in gas-phase.

Key words: R2HNO, R2NOH, isomer, thermodynamic stability, dynamic stability