物理化学学报 >> 2008, Vol. 24 >> Issue (05): 755-759.doi: 10.3866/PKU.WHXB20080504

研究论文 上一篇    下一篇

As-5、[As5M]-、[As5MAs5]2- (M=Ti, Zr, Hf)的结构和芳香性

李志伟; 赵存元; 陈六平   

  1. 肇庆学院化学化工学院, 广东 肇庆 526061; 中山大学化学与化学工程学院, 广州 510275
  • 收稿日期:2007-12-24 修回日期:2008-01-31 发布日期:2008-05-05
  • 通讯作者: 赵存元 E-mail:ceszhcy@mail.sysu.edu.cn

Structures and Aromaticities of As-5, [As5M]-, and [As5MAs5]2- (M=Ti, Zr, Hf)

LI Zhi-Wei; ZHAO Cun-Yuan; CHEN Liu-Ping   

  1. College of Chemistry and Chemical Engineering, Zhaoqing University, Zhaoqing 526061, Guangdong Province, P. R. China; School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, P. R. China
  • Received:2007-12-24 Revised:2008-01-31 Published:2008-05-05
  • Contact: ZHAO Cun-Yuan E-mail:ceszhcy@mail.sysu.edu.cn

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摘要： 用密度泛函理论(DFT)研究了As-5、[As5M]-和[As5MAs5]2- (M=Ti, Zr, Hf)的结构、频率、能量以及芳香性, 详细讨论了体系中不同类型的键和电子如化学键、孤对电子、核电子等对总的核独立化学位移(NICS)的影响. 结果表明, As-5、[As5M]-和[As5MAs5]2-的基态结构分别具有D5h、C5v和D5h对称性, 而且都具有芳香性. As-5 (D5h)的芳香性主要来源于As—As π键和As—As σ键的作用. [As5M]-(C5v)中各种As—M键的NICS分割值占主要优势, 其次是As—As之间形成的σ键. [As5TiAs5]2-(D5h)中, As—As π键的作用占主要优势. [As5ZrAs5]2-(D5h)中, As—As π键对体系总的NICS贡献相对减小, 而As—Zr键的作用增强. [As5HfAs5]2-(D5h)的芳香性主要来自As—Hf键的作用.

关键词: 核独立化学位移, 芳香性, 夹心型配合物

Abstract: The structures, energies, harmonic vibrational frequencies, and nucleus independent chemical shifts (NICS) of As-5 , [As5M]- and [As5MAs5]2-(M=Ti, Zr, Hf) were calculated by the density functional theory (DFT) . The dissected NICS of these species were computed to discuss the NICS contributions of the σ bonds, π bonds, lone pairs, and core electrons of As and M atoms. The calculations showed that the ground states of As-5, [As5M]-, and [As5MAs5]2- were in D5h, C5v, and D5h symmetries, respectively, and they were aromatic with negative NICS values. The dissected NICS indicated that the aromaticity of As-5 (D5h) mainly arised fromthe contributions of As—As π and As—As σ bonds, and the total NICS of [As5M]-(C5v) were dominated by the contributions of As—M bonds with the As—As σ bond followed. The total NICS of [As5TiAs5]2-(D5h) arised mainly from the As—As π bonds, and in the [As5ZrAs5]2-(D5h), the contribution of the As—As π bonds reduced while the contribution of the As—Zr bond increased relatively. In the [As5HfAs5]2- (D5h), the aromaticity mainly owed to the effects of the As—Hf bonds.

Key words: Nucleus independent chemical shifts, Aromaticity, Sandwich complex