大学化学 >> 2022, Vol. 37 >> Issue (1): 2104033.doi: 10.3866/PKU.DXHX202104033

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一种改进的休克尔分子轨道模型预测纯碳环分子稳定结构

张亦弛, 侯华, 王宝山()   

  • 收稿日期:2021-04-13 录用日期:2021-05-06 发布日期:2021-05-20
  • 通讯作者: 王宝山 E-mail:baoshan@whu.edu.cn
  • 作者简介:王宝山,Email: baoshan@whu.edu.cn
  • 基金资助:
    武汉大学通识课程教学改革项目

A Modified Hückel Molecular Orbital Model to Predict the Structure of Cyclo[2n]carbons

Yichi Zhang, Hua Hou, Baoshan Wang()   

  • Received:2021-04-13 Accepted:2021-05-06 Published:2021-05-20
  • Contact: Baoshan Wang E-mail:baoshan@whu.edu.cn

摘要:

针对休克尔分子轨道(HMO)理论中只考虑相邻原子轨道相互作用的缺点,提出了一种改进的HMO模型,明确考虑间位碳原子共振积分,采用对称性匹配的分子轨道,得到了π共轭体系的能级公式,发现分子对称性降低可产生额外稳定化能,从而正确解释了纯碳环C2n分子稳定结构中键角交替变化规律,为理解二级Jahn-Teller效应提供了新思路。

关键词: 休克尔分子轨道理论, 共振积分, 纯碳环, 对称性, 能级

Abstract:

Hückel Molecular Orbital (HMO) theory is popular in chemistry, but it assumes that the reduced resonance integrals exist only between the nearest-neighbor carbon atoms. Such an approximation has been justified by the explicit inclusion of the resonance integrals between the meta-directing π-bonded atoms. The energy eigenvalues are obtained using the symmetry-adapted molecular orbitals, together with the extra stabilization energy due to symmetry breaking. The polyynic geometries of cyclo[2n]carbons with alternating angles are explained rationally using the modified HMO model, which gains new insights on the second-order Jahn-Teller effect for carbon rings.

Key words: Hückel molecular orbital theory, Resonance integral, Carbon ring, Symmetry, Energy level

  • G64