高等学校化学学报

高等学校化学学报 ›› 2013, Vol. 34 ›› Issue (2): 455.doi: 10.7503/cjcu20120363

• 物理化学 • 上一篇    下一篇

NiTi过渡金属团簇的结构和芳香性的理论研究

时圣刚1,2, 封继康1, 田维全1, 刘子忠1, 李伟奇1, 崔艳红1   

  1. 1. 吉林大学理论化学研究所, 理论化学计算国家重点实验室, 长春 130021;
    2. 包头师范学院化学学院, 包头 014030
  • 收稿日期:2012-04-16 出版日期:2013-02-10 发布日期:2013-01-21
  • 通讯作者: 封继康,男,教授,博士生导师,主要从事理论化学研究.E-mail:jikangf@yahoo.com E-mail:jikangf@yahoo.com
  • 基金资助:

    国家自然科学基金(批准号: 20473031)资助.

Theoretical Studies on Structures and Aromaticity of NiTi Clusters

SHI Sheng-Gang1,2, FENG Ji-Kang1, TIAN Wei-Quan1, LIU Zi-Zhong1, LI Wei-Qi1, CUI Yan-Hong1   

  1. 1. State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130021, China;
    2. College of Chemistry, Baotou Teachers'College, Baotou 014030, China
  • Received:2012-04-16 Online:2013-02-10 Published:2013-01-21

PDF (PC)

被引次数

15

摘要：

在B3PW91/6-311+G(d)计算水平上, 计算并讨论了Ni4Ti2, [Ni4Ti2]2+, [Ni4Ti2]2-与Ni4Ti4, [Ni4Ti4]2+, [Ni4Ti4]2-团簇的几何结构和芳香性. 在构型优化过程中得到了Ni4Ti2(D4h), [Ni4Ti2]2+(D4h), [Ni4Ti2]2-(D4h)和Ni4Ti4(D2h)4个稳定构型, 发现当引入上下2个Ti原子后, Ni4环成为了平面正方形构型. 核无关化学位移(NICS)计算结果表明, Ni4Ti2(D4h)与Ni4Ti4(D2h)的NICS值为正, 而[Ni4Ti2]2+(D4h)和[Ni4Ti2]2-(D4h)的NICS值为负, 且[Ni4Ti2]2-(D4h)的NICS值更负. 同时还发现, 由s与d轨道参与形成的反磁性环流是引起[Ni4Ti2]2+(D4h)和[Ni4Ti2]2-(D4h)具有较大芳香性的主要原因; 其中Ti原子主要提供dz2与s轨道, 而Ni原子主要利用其dz2与dx2-y2轨道形成正方形环, 它们之间构成了球状的d轨道环流, 且[Ni4Ti2]2+(D4h)和[Ni4Ti2]2-(D4h)中还有非常明显的π轨道环流.

关键词: 密度泛函理论, 芳香性, 核无关化学位移, NiTi形状记忆合金

Abstract:

Ni4Ti2, [Ni4Ti2]2+ and [Ni4Ti2]2-, Ni4Ti4, [Ni4Ti4]2+ and [Ni4Ti4]2- were studied at the B3PW91/6-311+G(d) basis level with density functional theory(DFT). Introduction of Ti atoms to both sides of Ni4 ring brings about stable conformations Ni4Ti2(D4h), [Ni4Ti2]2+(D4h), [Ni4Ti2]2-(D4h) and Ni4Ti4(D2h) with square-planar ring of Ni4. Nucleus-independent chemical shifts(NICS) calculations show positive NICS value in Ni4Ti2(D4h) and Ni4Ti4(D2h), negative NICS value in [Ni4Ti2]2+(D4h), and more negative NICS value in [Ni4Ti2]2-(D4h). Analysis results show that the formation of diamagnetic circulation involving s and d orbitals is the main cause for the relatively strong aromaticity of [Ni4Ti2]2+(D4h) and [Ni4Ti2]2-(D4h). In such case, Ti atoms provide dz2 and s orbitals, and Ni atoms form square with their dz2 and dx2-y2 orbitals, with which a spherical electron current forms in [Ni4Ti2]2+(D4h) and [Ni4Ti2]2-(D4h) with conspicuous π electron current.

Key words: Density functional theory, Aromaticity, Nucleus-independent chemical shift, NiTi shape memory alloy

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