物理化学学报 >> 2015, Vol. 31 >> Issue (6): 1086-1092.doi: 10.3866/PKU.WHXB201504162

理论与计算化学 上一篇    下一篇

叠氮桥对双核镍配合物磁性影响的密度泛函理论研究

边江鱼1, 岳淑美1, 张敏1, 张景萍2   

  1. 1 长春师范大学化学学院, 长春130032;
    2 东北师范大学化学学院, 长春130024
  • 收稿日期:2015-01-15 修回日期:2015-04-15 发布日期:2015-06-05
  • 通讯作者: 边江鱼, 张景萍 E-mail:bianjy2002@163.com;zhangjp162@nenu.edu.cn
  • 基金资助:

    长春师范学院自然科学基金(长师院自科合字[2009]第009 号, 长师院自科合字政策[2010]第030 号)和吉林省教育厅科学技术研究“十二五”规划项目(吉教科合字[2011]第192 号)资助

Effects of Azido Bridge on Magnetic Properties of Dinuclear Nickel Complexes: Density Functional Theory Studies

BIAN Jiang-Yu1, YUE Shu-Mei1, ZHANG Min1, ZHANG Jing-Ping2   

  1. 1 Department of Chemistry, Changchun Normal University, Changchun 130032, P. R. China;
    2 Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. China
  • Received:2015-01-15 Revised:2015-04-15 Published:2015-06-05
  • Contact: BIAN Jiang-Yu, ZHANG Jing-Ping E-mail:bianjy2002@163.com;zhangjp162@nenu.edu.cn
  • Supported by:

    The project was supported by the Natural Science Foundation of Changchun Normal University, China (2009-009, 2010-030) and“Twelfth Five- Year Plan”Science and Technology Research Projects of Jilin Provincial Department of Education, China (2011-192).

摘要:

结合对称性破损(BS)方法, 采用不同的密度泛函理论(DFT)对反铁磁性μ-1,3-N3-Ni(II)叠氮配合物[LNi2(N3)](ClO4)2 (L=pyrazolate)的磁特性进行了研究. 结果显示, 杂化密度泛函理论(HDFT)的计算结果与实验数据非常吻合, 能够准确描述配合物的磁特性. 磁轨道研究结果表明, 配合物表现出较大的单占据轨道能量劈裂(0.93-0.99 eV), 显示配合物的单占据轨道去简并化程度较大, 且配合物中的2 个磁通道(叠氮基、配体pyrazolate)中都分别存在有氮原子之间的p轨道重叠, 这些都使得体系表现为反铁磁耦合作用. 另外, 配合物的磁性与叠氮桥和两金属离子间形成的二面角(τ, Ni-N-N-N-Ni)密切相关, τ从-55.38°逐渐变化到-1.5°的过程中, 其反铁磁性逐渐增强, 交换耦合常数(Jab)的绝对值逐渐增大, 并在-11.95°处达到最大值(Jab=-151.02 cm-1).在此过程中, 配合物中叠氮桥及其所连接的2个Ni 离子与pyrazolate 基配体L-中的2个桥原子N(4)、N(5)形成的七元环共平面性不断增强, 即共平面性会诱导增强体系的反铁磁相互作用.

关键词: 密度泛函理论-对称性破损方法, 叠氮配合物, 交换耦合常数, 反铁磁相互作用

Abstract:

The magnetic properties of the antiferromagnetic complex μ-1,3-N3-Ni(II)[LNi2(N3)](ClO4)2 (L= pyrazolate) were investigated using density functional theory (DFT) calculations combined with the broken symmetry approach. The calculation results obtained using the hybrid density functional theory (HDFT) agree well with the experimental data, and accurately describe the magnetic properties of complex. The large energy splitting, 0.93-0.99 eV, between singly occupied molecular orbitals indicates that there is strong non-degeneracy between them, and the two coupling paths (azido and pyrazolate) in the complex show that there is overlap between the p orbitals of the N atoms. All these factors contribute to the antiferromagnetism of the complex. The magnetic properties of the complex are also closely related to the dihedral angle τ of Ni-N-N-N-Ni. The antiferromagnetism of the complex increases as τ decreases from -55.38° to -1.5°; the maximum absolute value of magnetic coupling constant (Jab) occurs at -11.95° (Jab=-151.02 cm-1). During this process, the coplanarity of the seven-membered ring, which consists of two Ni(II), one azido, and two bridging nitrogen atoms (N(4) and N(5)), is enhanced, i.e., coplanarity increases the antiferromagnetism of the complex.

Key words: Density functional theory-broken symmetry (DFT-BS) method, Azido complex, Magnetic coupling constant, Anti-ferromagnetic interaction

MSC2000: 

  • O641