物理化学学报 >> 2012, Vol. 28 >> Issue (05): 1113-1119.doi: 10.3866/PKU.WHXB201203071

理论与计算化学 上一篇    下一篇

包含平面五配位和平面四配位碳化合物的结构和稳定性

吴林峰, 李飞飞, 张聪杰   

  1. 陕西师范大学化学与化工学院, 陕西省大分子科学重点实验室, 西安 710062
  • 收稿日期:2011-12-21 修回日期:2012-02-21 发布日期:2012-04-26
  • 通讯作者: 张聪杰 E-mail:zcjwh@snnu.edu.cn
  • 基金资助:

    2010 年度中央高校基本科研业务费专项资金(GK201002013)和厦门大学固体表面物理化学国家重点实验室开放课题(2010)资助

Structure and Stability of Compounds with Planar Pentacoordinate Carbons and Planar Tetracoordinate Carbons

WU Lin-Feng, LI Fei-Fei, ZHANG Cong-Jie   

  1. Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shannxi Normal University, Xi'an 710062, P. R. China
  • Received:2011-12-21 Revised:2012-02-21 Published:2012-04-26
  • Contact: ZHANG Cong-Jie E-mail:zcjwh@snnu.edu.cn
  • Supported by:

    The project was supported by the Fundamental Research Funds for the Central Universities, China (GK201002013) and State Key Laboratory for Physical Chemistry of Solid Surface (Xiamen University), China (2010).

摘要: 在B3LYP/6-311+G**水平上, 研究了包含平面五配位碳(ppC)和平面四配位碳(ptC)的化合物CB5C2H2(C3B2)nC2H2CB5 (n=1-5)的结构、能隙、IR 光谱、电子光谱、Wiberg 键指数以及芳香性. 计算结果表明, 这五种化合物的能量最低结构均位于势能面的极小值点, HOMO-LUMO能隙在0.5 到1.2 eV之间, 第一电子的激发能在1780到2910 nm之间, 且与分子尺寸呈现非单调变化趋势. Wiberg 键指数和键长表明这五种化合物的能量最低结构均包含平面五配位和平面四配位碳. C3B2 单元和右侧CB5 单元中三元环中心的核独立化学位移(NICS(0))值均为负值, 而左侧CB5单元中的三元环中心的NICS(0)值中两个为正值, 另两个为负值, NICS(1)值与NICS(0)值也一致, 因此电子的局域离域对结构的稳定是很重要的.

关键词: 密度泛函理论, 平面五配位碳原子, 平面四配位碳原子, 芳香性

Abstract: We have investigated the structures, gaps, IR spectra, electronic spectra, Wiberg bond indices (WBIs), and aromaticity of CB5C2H2(C3B2)nC2H2CB5 (n=1-5) with planar pentacoordinate carbons (ppC) and planar tetracoordinate carbons (ptC) at the B3LYP/6-311 + G** level. Calculations indicate that the five compounds with the lowest energies are located at the minima of the potential energy surfaces. The energy gaps between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) vary between 0.5 and 1.2 eV; the first electronic transition wavelengths are between 1780 and 2910 nm and depend non-monotonically on the size of the compounds. WBIs of the five compounds show that they contain both ppC and ptC. The nucleus-independent chemical shift (NICS(0)) values of the centers of the three-membered rings of the CB5 sections on the right side of these compounds, as well as the C3B2 sections, are negative, while the NICS(0) values of only two centers of the three-membered rings of the CB5 sections on the left side are negative. In addition, since the NICS(0) of the centers of the three-membered rings are consistent with those of NICS(1), then local delocalization of the π electrons must play an important role in stabilizing these compounds.

Key words: Density functional theory, Planar pentacoordinate carbon atom, Planar tetracoordinate carbon atom, Aromaticity

MSC2000: 

  • O641