高等学校化学学报 ›› 2022, Vol. 43 ›› Issue (4): 20210807.doi: 10.7503/cjcu20210807

• 物理化学 • 上一篇    下一篇

平面五配位硅、 锗XBe5H6(X=Si, Ge)团簇

郭谨昌(), 刘芳林   

  1. 山西大学分子科学研究所, 纳米团簇实验室, 太原 030006
  • 收稿日期:2021-11-29 出版日期:2022-04-10 发布日期:2022-02-17
  • 通讯作者: 郭谨昌 E-mail:guojc@sxu.edu.cn
  • 基金资助:
    国家自然科学基金(22173053)

Planar Pentacoordinate Silicon and Germanium in XBe5H6(X=Si, Ge) Clusters

GUO Jinchang(), LIU Fanglin   

  1. Nanocluster Laboratory,Institute of Molecular Science,Shanxi University,Taiyuan 030006,China
  • Received:2021-11-29 Online:2022-04-10 Published:2022-02-17
  • Contact: GUO Jinchang E-mail:guojc@sxu.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(22173053)

摘要:

采用密度泛函理论PBE0方法, 在aug-cc-pVTZ水平上理论预测了含平面五配位硅和锗原子的XBe5H6 (X=Si, Ge)团簇. 势能面系统搜索及高精度量化计算表明, 它们均为全局极小结构. XBe5H6(X=Si, Ge)团簇整体呈完美的扇形结构: Si/Ge原子被5个金属Be原子配位; 4个H原子以桥基方式与Be原子相键连, 剩余的2个 H原子以端基方式与两端的Be原子成键. 化学键分析表明, XBe5H6(X=Si, Ge) 团簇中XBe5单元具有完全离域的1个π及3个σ键, 外围铍氢间形成4个Be—H—Be 三中心二电子(3c-2e)键及2个定域的Be—H键. XBe5单元上离域的2π及6σ电子赋予体系πσ双重芳香性, 并使Si/Ge原子满足八隅律(或八电子规则). 能量分解-化学价自然轨道分析揭示, Si/Ge和Be5H6之间主要为电子共享键.

关键词: 平面五配位硅, 全局极小结构, 化学键, π/σ双重芳香性, 八电子规则

Abstract:

Computational design of ternary XBe5H6(X=Si, Ge) clusters was reported, which were global-minimum structures on the potential energy surfaces, featuring planar pentacoordinate silicon/germanium(ppSi/Ge). XBe5H6 (X=Si, Ge) clusters have the perfect fan-shaped structures: Si/Ge atoms are coordinated by five Be atoms; four H atoms are bonded to Be atoms in bridge mode, and the remaining two H atoms are bonded to Be atoms at both ends. Chemical bonding analyses reveal that the ppSi/Ge core is governed by delocalized 2π/6σ bonding, that is, double π/σ aromaticity, which also makes the Si/Ge atom conform to the octet rule. Additional twelve electrons are contributed to peripheral Be—H—Be and Be—H σ bonding. Energy decomposition analysis-Natural orbital for chemical valence(EDA-NOCV) analyses indicate that there is mainly electron-sharing bonding between the Si/Ge and Be5H6 ligands.

Key words: Planar pentacoordinate silicon, Global minimum structure, Chemical bonding, Double π/σ aromati-city, Eight-electron counting

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