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化学学报
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化学学报 ›› 2006, Vol. 64 ›› Issue (4): 306-312. 上一篇    下一篇

研究论文

NO2气相硝化金刚烷的计算研究

许晓娟1,2，肖鹤鸣*,1，贡雪东1，居学海1   

  1. (1南京理工大学化学系 南京 210094)
    (2盐城师范学院化学系 盐城 224002)
  • 投稿日期:2005-05-08 修回日期:2005-10-24 发布日期:2006-02-28
  • 通讯作者: 肖鹤鸣

Computational Studies on the Nitration of Adamantane with NO2

XU Xiao-Juan1,2, XIAO He-Ming*,1, GONG Xue-Dong1, JU Xue-Hai1   

  1. (1 Chemistry Department of Nanjing University of Science and Technology, Nanjing 210094)
    (2 Yancheng Normal College, Yancheng 224002)
  • Received:2005-05-08 Revised:2005-10-24 Published:2006-02-28
  • Contact: XIAO He-Ming

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运用密度泛函理论(DFT)和半经验MO-PM3方法研究了NO2气相硝化金刚烷反应机理. 计算结果表明, NO2不能直接取代金刚烷H; 在B3LYP/6-311＋＋G(3df,2pd)//B3LYP/6-31G* 较高水平下, 对三个可能机理的反应势垒(Ea)的精确计算表明, 该反应的决速步骤为NO2中O和N进攻1-H的竞争过程, 且1-硝基金刚烷为主要产物. NO2中O进攻1-H决速反应过程中, 分子几何、原子自然电荷及IR光谱变化表明, C—H键的断裂和N—H键的形成是一个协同过程; 参与新键形成和旧键断裂原子C(1), H(11), O(28), O(29)和N(27)的原子自然电荷及与其相关的键长、键角有明显的变化. 反应过程中体系偶极矩的变化表明, 极性溶剂能降低反应势垒, 有利于反应的进行.

关键词: 金刚烷, 密度泛函理论, 硝化机理, 反应势垒

The density functional theory (DFT) and semi-empirical MO-PM3 methods were employed to study the reaction mechanism of the nitration of adamantane with NO2. The calculated results showed that the H atom in adamantane can not be directly substituted with NO2. By comparing the potential barriers Ea of the three possible reaction mechanisms at the B3LYP/6-311＋＋G(3df,2pd)//B3LYP/6-31G* level, it was found that the process of N to attack H competed with that of O to attack H during the crucial step, and 1-nitroadamantane was considered to be the main product. In addition, the changes of molecular geometry, atomic natural charge and IR spectra of the reaction system during the crucial step of O to attack H showed that the rupture of C—H bond and the formation of O—H bond were concerted stepwise. Obvious changes of atomic natural charge happened to atoms C(1), H(11), O(28), O(29) and N(27). The bond lengths and bond angles related to these atoms were also varied greatly. The dipole moment changes predicted that polar solvent could decrease reaction potential barrier Ea to facilitate the reaction.

Key words: adamantane, density functional theory, nitration mechanism, potential barrier