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化学学报
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化学学报 ›› 2010, Vol. 68 ›› Issue (01): 7-12. 上一篇    下一篇

研究论文

包含两个平面五配位碳原子C2＋nB10－n (n＝0～10)团簇的结构的理论研究

梁锦霞，张聪杰   

  1. (陕西省大分子科学重点实验室 陕西师范大学化学与材料科学学院 西安 710062)
  • 投稿日期:2009-05-07 修回日期:2009-07-09 发布日期:2009-09-01
  • 通讯作者: 张聪杰 E-mail:zcjwh@snnu.edu.cn

Theoretical Study of the Structures of C2＋nB10－n (n＝0～10) Cluster with Two Planar Pentacoordinate Carbons

Liang Jinxia, Zhang Congjie   

  1. (Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry and Materials Science, Shaanxi Normal University, Xi  an 710062)
  • Received:2009-05-07 Revised:2009-07-09 Published:2009-09-01

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采用B3LYP/6-311＋G**方法, 我们优化了初始构型中包含两个平面五配位碳原子(ppCs)的C2＋nB10－n (n＝0～10)团簇的结构并计算了它们的振动频率. 计算结果表明, C2＋nB10－n (n＝0～2)团簇是稳定的, 而且这三个结构中ppC—B键的Wiberg键级介于0.511～0.909之间, ppC—C键的Wiberg键级为0.2254 (n＝1)和0.8586 (n＝2), ppC的键级介于3.778到3.879之间, 即这三个结构中存在两个ppCs, 而且ppC遵循八隅规则; C2＋nB10－n (n＝3～6)团簇的最稳定结构包含一个ppC; C2＋nB10－n (n＞6)团簇能量最低结构中不存在ppC. 而且只有团簇C2＋nB10－n (n＝0～2)中没有悬键, 它们的(电子数分别为: 6, 7和8, 计算它们的NICS(0)值表明强芳香性一般位于局部的三元环中心, 表明局部离域有利于平面结构的形成. C2＋nB10－n (n＝0～2)团簇的第一垂直激发能分别为: 1.91, 0.56和3.12 eV.

关键词: 杂化密度泛函, 平面五配位碳原子(ppC), 硼碳团簇, 芳香性

Using B3LYP/6-311＋G** method, the initial geometrical structures of boron-carbon clusters C2＋nB10－n (n＝0～10) containing double planar pentacoordinate carbon (ppC) were optimized and their vibrational frequencies were calculated. Present results showed that C2＋nB10－n (n＝0～2) clusters are stable, in which the Wiberg bond index (WBI) of ppC—B bonds are between 0.511 and 0.909 and the WBIs of ppC—C are 0.2254 (n＝1) and 0.8586 (n＝2), as well as the WBIs of ppC are 3.778 and 3.879, i.e. the three molecules include double ppCs and ppCs obey octal rule; the C2＋nB10－n (n＝3～6) clusters with the lowest energy contain one ppC, while the lowest energy C2＋nB10－n (n＞6) clusters have no ppC. In addition, only the C2＋nB10－n (n＝0～2) clusters do not include dangling bonds, and the numbers of ( electron in the C2＋nB10－n (n＝0～2) clusters are 6, 7 and 8, respectively. Calculated NICS(0) values indicate that the strong aromaticity mainly locates at the centers of the three-membered rings. The vertical transition energies of C2＋nB10－n (n＝0～2) clusters are 1.91, 0.56 and 3.12 eV.

Key words: hybrid density functional, planar pentacooridinate carbon (ppC), boron-carbon cluster, aromaticity