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化学学报
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化学学报 ›› 2009, Vol. 67 ›› Issue (8): 773-780. 上一篇    下一篇

研究论文

硅烯与异硫氰酸反应机理的量子化学研究

韩彦霞a,b,c 耿志远*,a,b 王永成a,b 梁俊玺a,b 闫盆吉a,b

  

  1. (a西北师范大学化学化工学院 兰州 730070)
    (b甘肃省高分子重点实验室 兰州 730070)
    (c陇东学院化学化工学院 庆阳 745000)

  • 投稿日期:2008-06-01 修回日期:2008-11-24 发布日期:2009-04-28
  • 通讯作者: 耿志远

Theoretical Study of Reaction Mechanism of Silylene with Isothiocyanic Acid

Han, Yanxia a,b,c Geng, Zhiyuan *,a,b Wang, Yongcheng a,b
Liang, Junxi a,b Yan, Penji a,b
  

  1. (a College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070)
    (b Gansu Key Laboratory of Polymer Materials, Northwest Normal University, Lanzhou 730070)
    (c College of Chemistry and Chemical Engineering, Longdong University, Qingyang 745000)
  • Received:2008-06-01 Revised:2008-11-24 Published:2009-04-28
  • Contact: Geng, Zhiyuan

PDF

1275

被引次数

24 | 3

采用密度泛函理论B3LYP方法在B3LYP/6-311＋＋G**水平上对反应物、中间体、过渡态进行了全几何参数优化, 通过频率分析和IRC方法确认了中间体和过渡态. 又用QCISD(T)/6-311＋＋G**//B3LYP/6-311＋＋G**方法计算了各个驻点的单点能, 计算结果表明单重态的硅烯与异硫氰酸的反应有抽提硫、插入、抽提亚氨基的路径. 而经由三元环中间体的抽提硫反应SiH2＋HNCS→IM1→TS2→IM3→TS3→IM4→SiH2S＋HNC(P1), 反应能垒最低, 为主反应通道, 硫代硅甲醛和异氰氢酸为主产物. 硅烯直接抽提硫、插入N—H键和经由三元环中间体的亚氨基抽提反应为竞争反应通道, 在室温下可以发生, 应为次反应通道.

关键词: 硅烯, 异硫氰酸, 反应机理, 活化能, 过渡态

Using the DFT-B3LYP based on 6-311++G** basis set, the geometries of the reactants, the intermediates and the transition states were fully optimized at the B3LYP/6-311++G** level. The intermediates and the transition states were examined by using the frequency calculations and the intrinsic reaction coordinate (IRC). Furthermore, single-point energy calculations were refined at the QCISD level of theory with the same basis set (6-311++G**). As a result, the singlet reaction of silylene with isothiocyanic acid contain S-atom abstraction channel, N—H inserted channel, and NH abstraction channel, respectively. The pathway written as SiH2＋HNCS→IM1→TS2→IM3→TS3→IM4→SiH2S＋HNC(P1) was the main pathway, whose the activation energy was the lowest and the primary products were SiH2S and HNC, respectively. While the channel of NH abstraction, which was a minor channel comparing those of direct S-atom abstraction and N—H insertion, was the competitive reaction channel and can process under the room temperature.

Key words: silylene, isothiocyanic acid, reaction mechanism, activation energy, transition state