物理化学学报 >> 1986, Vol. 2 >> Issue (06): 541-548.doi: 10.3866/PKU.WHXB19860610

研究论文 上一篇    下一篇

卟吩复合体的电子结构

严继民; 赵建国   

  1. 中国科学院化学研究所
  • 收稿日期:1985-03-29 修回日期:1986-04-03 发布日期:1986-12-15

ELECTRONIC STRUCTURE OF THE PORPHIN DIMER

Yan Jimin; Zhao Jianguo

  

  1. Institule of Chemistry; Academia Sinica; Beijing
  • Received:1985-03-29 Revised:1986-04-03 Published:1986-12-15

摘要: 本文用EHMO法对卟吩及其复合体的电子结构进行了计算。由卟吩复合体的差示电荷分布的分析表明, 在卟吩复合体中卟吩分子属于两性电子施受体, 分子中有固定的施体中心和受体中心部位。体系在相对取向角φ为45°时能量最小。两个分子相对旋转一周要克服四重势垒, 势垒高度为~0.09 eV。本文把简并态微扰理论推广运用于两个分子组成的复合物体系, 并由此定量地解释了卟吩与其复合体之间存在的能级对应现象。

Abstract: The electronic structures of the porphin and its dimer have been calculated by EHMO.From the differential charge distribution in the porphin dimer it has been shown that the porphin molecule belongs to the amphoteric electron donor-aceeptor in its dimer, having steady donor centers and acceptor centers. The system has minimum energy at the orientation angle ψ=45°. 4-fold barriers should be overcome when two monomers rotate each other. The barrier is ~0.09 eV. The degenerate perturbation theory has been expanded to deal with the dimer system, and according to this result the energy level corespondence between the monomer and the dimer has been explained quantitatively. It has been shown that the cause of the interaction is the charge transfer between the donor center and the acceptor center in the dimer.
The model for calculation is shown in Fig.1. The frontier orbitals and those nearby them are all π ones (ref. Table 1), and the difference between the π-π interaction energy and the total energy is less than 10% of the total one. Thereby, we only calculate the π-π interaction for simplicity.
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