高等学校化学学报 ›› 2019, Vol. 40 ›› Issue (5): 980-987.doi: 10.7503/cjcu20180804

• 物理化学 • 上一篇    下一篇

金属串配合物[MM'M″(dpa)4(Cl)2](M=Co, Ni; M',M″=Co, Rh)电子输运的理论研究

郅莎莎1, 班颖1, 徐志广1, 许旋1,2,3()   

  1. 1. 华南师范大学化学与环境学院
    2. 教育部环境理论化学重点实验室
    3. 广州市能源转化与储能材料重点实验室, 广州 510006
  • 收稿日期:2018-11-28 出版日期:2019-04-04 发布日期:2019-04-04
  • 作者简介:

    联系人介绍: 许 旋, 女, 博士, 教授, 主要从事量子化学理论研究. E?mail: xuxuan@scnu.edu.cn

  • 基金资助:
    广东省自然科学基金(批准号: 9151063101000037)、 广东省教育厅产学研项目(批准号: 2010B090400184)、 广东省人才引进专项基金(批准号: C10133)和广州市科技攻关项目(批准号: 2011J4300063)资助.

Electron Transport of Metal String Complexes of [MM'M″(dpa)4(Cl)2](M=Co, Ni; M',M″=Co, Rh)

ZHI Shasha1, BAN Ying1, XU Zhiguang1, XU Xuan1,2,3,*()   

  1. 1. School of Chemistry & Environmen
    2. Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education
    3. Key Laboratory of Material for Energy Conversion and Storage of Guangzhou, South China Normal University, Guangzhou 510006, China
  • Received:2018-11-28 Online:2019-04-04 Published:2019-04-04
  • Contact: XU Xuan E-mail:xuxuan@scnu.edu.cn
  • Supported by:
    † Supported by the Natural Science Foundation of Guangdong Province, China(No.9151063101000037), the Research Project of Ministry of Education and Guangdong Province, China(No.2010B090400184), the Program of Talent Introduction of Guangdong Province, China(No.C10133) and the Science and Technology Program of Guangzhou City, China(No.2011J4300063)

摘要:

采用密度泛函理论DFT/BP86方法研究金属串配合物[MM'M″(dpa)4(Cl)2] [MM'M″=CoCoCo(1), CoCoRh(2), CoRhRh(3), NiCoRh(4)] 的结构和电子输运性质. 结果表明, 配合物1, 2和4的最稳定自旋态均存在1个(MM'M″)6+的离域$\sigma_{3}^{3}$键($\sigma^{2}\sigma_{nb}^{1}\sigma^{*0}$); 但配合物3具有1个(MM'M″)6+的离域$\sigma_{3}^{4}$键($\sigma^{2}\sigma_{nb}^{2}\sigma^{*0}$)和2个$\pi_{3}^{5}$键($\pi^{4}\pi_{nb}^{4}\pi^{*2}$), 故Rh—Rh键和Co—Rh键较强; Rh的引入使M—M键增强, Ni的引入则使M—M键减弱, 键强次序为Rh—Rh>Co—Rh>Co—Co>Ni—Co. 配合物14的传输通道均含有πσ型轨道. 正偏压下, 配合物2和3的电流大于配合物1和4的. 负偏压下, 配合物4中出现负微分电阻效应. 配合物3中形成传输通道的σnbα/βπ*α/β轨道能级分裂明显, (MM'M″)6+β自旋的π*轨道的贡献(88%)比α自旋(74%)的大, 使β自旋的电子更易传输, 具有较好的自旋过滤效应(70%80%).

关键词: 金属串配合物, 密度泛函理论, 电子传输, 自旋过滤

Abstract:

The electronic structures and transmission properties of metal string complexes [MM'M″(dpa)4·(Cl)2][MM'M″=CoCoCo(1); CoCoRh(2); CoRhRh(3); NiCoRh(4)] were investigated by density functional theory BP86 method. The results show that there is a delocalized 3-center-3-lectron σ bond of (MM'M″)6+ among complexes 1, 2 and 4, while there are one delocalized 3-center-4-electron σ bond of (MM'M″)6+ and two 3-center-5-electron π bonds in complex 3. The Rh—Rh bond of complex 3 is the strongest among complexes 1—4 and the Co—Rh bond is second on account of above-mentioned information. The substitution of Rh enhanced the M—M bond, and the replace of Ni weakened the M—M bond. In conclusion, the order of bond is Rh—Rh>Co—Rh>Co—Co>Ni—Co. The transport channels of complexes 1—4 contain π-type and σ-type orbitals. Under positive bias, the currents in complexes 2 and 3 are greater than complexes 1 and 4. Under negative bias, there is a negative differential resistance effect in complex 4. The energy splitting of σnbα/β and π*α/β orbit as transport channels in complex 3 are the most obvious among complexes 1—4. Moreover, the contribution of (MM'M″)6+ to the π* orbit of β spin(up to 88%) is larger than that of α (up to 74%). Thus, the electronic transmission of β spin channel is stronger than α spin. To sum up, the complex 3 has significant spin filter effect (up to 70%—80%).

Key words: Metal string complex, Density functional theory(DFT), Electronic transport, Spin filter effect

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