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化学学报
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化学学报 ›› 2009, Vol. 67 ›› Issue (7): 599-606. 上一篇    下一篇

研究论文

乙醛二聚体内蓝移型氢键的理论研究

杨 颙*,a 张为俊b

  

  1. (a安徽建筑工业学院材料与化学工程学院 先进建筑材料安徽省重点实验室 合肥 230022)
    (b中国科学院安徽光学精密机械研究所环境光谱学实验室 合肥 230031)

  • 投稿日期:2008-07-13 修回日期:2008-10-09 发布日期:2009-04-14
  • 通讯作者: 杨颙

Theoretical Study on Blue-shifted Hydrogen Bonds in CH3CHO Dimers

Yang, Yong*,a Zhang, Weijun b   

  1. (a Anhui Key Laboratory of Advanced Building Materials, School of Materials Science and Chemical Engineering, Anhui
    Institute of Architecture & Industry, Hefei 230022)
    (b Environmental Spectroscopy Laboratory, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences,
    Hefei 230031)
  • Received:2008-07-13 Revised:2008-10-09 Published:2009-04-14

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利用理论方法研究了乙醛二聚体内的氢键. 在MP2/6-31＋G(d), B3LYP/6-31＋G(d), B3LYP/6-311＋＋G(d,p)和B3LYP/6-311＋＋G(3df,2p)水平上, 利用常规方法和均衡校正方法对3种稳定的乙醛二聚体进行了几何优化和振动频率计算. 计算结果表明: 在二聚体A和C中乙醛中C—H键强烈收缩, 存在显著的C—H…O蓝移型氢键. 自然键轨道(NBO)分析表明, 电子供体轨道和电子受体轨道之间相互作用的稳定化能、分子内电子密度重排、轨道再杂化和结构重组是决定氢键红移和蓝移的主要因素. 其中, 轨道间稳定化能属于键伸长效应, 分子内电子密度重排、轨道再杂化和电子受体内部结构重组属于键收缩效应. 在二聚体A和C中, 由于键收缩效应处于优势地位导致C—H…O蓝移氢键存在.

关键词: 红移型氢键, 蓝移型氢键, 电子密度拓扑分析, 自然键轨道分析

Theoretical calculations were performed to study the nature of the hydrogen bonds in the CH3CHO dimers. The geometric structures and vibrational frequencies of its three stable dimers at the MP2/6-31＋G(d), B3LYP/6-31＋G(d), B3LYP/6-311＋＋G(d,p) and B3LYP/6-311＋＋G(3df,2p) levels were calculated by standard and counterpoise-corrected methods, respectively. The results indicate that in the dimers A and C the C—H bond is strongly contracted and C—H…O blue-shifted hydrogen bonds were observed. From the natural bond orbital analysis it can be seen that the X—H bond length in the X—H…Y hydrogen bond is controlled by a balance of four main factors in the opposite directions: hyperconjugation, electron density redistribution, rehybridization and structural reorganization. Among them the hyperconjugation has the effect of elongating the X—H bond, but the other three factors belong to the bond shortening effects. In the dimers A and C, the shortening effects dominate which lead to the blue shift of the C—H stretching frequencies.

Key words: red-shifted H-bond, blue-shifted H-bond, AIM topological analysis, NBO analysis