化学学报 ›› 2001, Vol. 59 ›› Issue (2): 173-178. 上一篇    下一篇

研究论文

叠氮酸桥联双核铜配合物磁偶合的密度泛函研究

项生昌;李俊钱;章永凡;周立新   

  1. 福州大学化学系结构化学国家重点实验室
  • 发布日期:2001-02-15

Ab initio calculation for magnetostructural characterization of azido-bridged Cu(Ⅱ) dimers

Xiang Shengchang;Li Junqian;Zhang Yongfan;Zhou Lixin   

  • Published:2001-02-15

在密度泛函理论的框架下,采用对称性破损态方法,对EE,EO两种连接方式叠氮酸桥联双核铜模型配合物进行计算,结果表明,EE方式连接为反铁磁偶合;EO方式则为铁磁偶合,但只发生在θ=91°~107°区间,与实验值96°~104°基本一致,研究揭示了其磁偶合构效关系的本质在于SOMOb1g轨道中Nμ的Px轨道与Cu的dxy轨道间的d-p-d三中心σ反键作用,在θ=91°~110°区间具有最大的反键重叠,因而铁磁偶合最大,同时发现J值随Cu与配位叠氮酸酸N原子间距离的增大而减小,但叠氮酸偏离平面的角度对J值影响不大。

关键词: 叠氮酸, 桥键, 对称性, 破损, 双核配合物, 叠氮络合物, 铁磁材料, 铜络合物, 构效关系, 密度函数

On basis of the broken symmetry approach and density functional theory (DFT), the magnetostructural characterization of azido-bridged c Cu(Ⅱ) dimers is studied which have end - to - end (EE) and end - on (EO) two main coordination modes. The calculating results show that EE mode gives antiferromagnetic interaction, whereas EO mode gives ferromagnetic coupling in which θis about 91°~107 °, basically agreealde with the experimental value 96°~104 °. The essence of the magnetostructural characterization lies in d - p - d three centers σ antibonding action between two Cu dxy orbitals and bridged N px orbital in SOMO b1g. In the θ region of 95°~ 110 ° the σ antibonding overlap has the maximum, which leads to the maximum ferromagnetic coupling. It is also shown that τhas no great influence on J, whereas J decreases linearly with increasing rCu-Nμ.

Key words: BRIDGE BOND, SYMMETRY, FAILURE, DINUCLEAR COMPLEX, AZIDO COMPLEX, FERROMAGNETIC MATERIALS, COPPER COMPLEX, STRUCTURE ACTIVITY RELATIONSHIP

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