高等学校化学学报 ›› 2012, Vol. 33 ›› Issue (08): 1799.doi: 10.3969/j.issn.0251-0790.2012.08.030

• 物理化学 • 上一篇    下一篇

基于非血红素铁模型配合物[Fe(O)(N4Py)]2+的新型N杂环卡宾配合物的理论设计

王一1, 张鹏2, 杨鲲3, 侯英敏1   

  1. 1. 大连工业大学 生物工程学院, 大连 116034;
    2. 大连工业大学 机械工程与自动化学院, 大连 116034;
    3. 大连海事大学物理系, 大连 116026
  • 收稿日期:2011-11-30 出版日期:2012-08-10 发布日期:2012-08-10
  • 通讯作者: 王 一, 女, 博士, 讲师, 主要从事非血红素铁模型配合物的理论研究. E-mail: wangyi@dlpu.edu.cn E-mail:wangyi@dlpu.edu.cn
  • 基金资助:

    国家自然科学基金(批准号: 11047110)资助.

Theoretical Design of a New N-Heterocyclic Carbene Complex Based on Non-heme Iron Complex [Fe(O)(N4Py)]2+

WANG Yi1, ZHANG Peng2, YANG Kun3, HOU Ying-Min1   

  1. 1. School of Biological Engineering, Dalian Polytechnic University, Dalian 116034, China;
    2. School of Mechanical Engineering and Automation, Dalian Polytechnic University, Dalian 116034, China;
    3. Department of Physics, Dalian Maritime University, Dalian 116026, China
  • Received:2011-11-30 Online:2012-08-10 Published:2012-08-10

摘要:

基于四价非血红素铁模型配合物[Fe(O)(N4Py)]2+, 通过理论计算设计出一种新型N杂环卡宾配合物[Fe(O)(N4Py)]2+. 采用密度泛函理论B3LYP方法, 计算了[Fe(O)(N4Py)]2+的几何结构和电子结构, 并研究了[Fe(O)(N4Py)]2+使环己烷C-H键羟基化的反应机理. 结果表明, [Fe(O)(N4Py)]2+的五重态能量比基态三重态能量高约5.7 kJ/mol, 故五重态几乎不能参与反应. 赤道方向的配位基N杂环卡宾(NHC)对FeO单元的σ-贡献要大于N4Py的贡献, 而它的空间位阻效应也大于N4Py, 因此2+的稳定性强于[Fe(O)(N4Py)]2+. [Fe(O)(N4Py)]2+的三重态的反应能垒比[Fe(O)(N4Py)]2+的三重态反应能垒高2.0 kJ/mol, 且为单态反应, 所以[Fe(O)(N4Py)]2+的反应活性要高于[Fe(O)(N4Py)]2+.

关键词: 非血红素, N杂环卡宾, 密度泛函理论, 轨道系数, 反应机理

Abstract:

Based on non-heme iron complex [Fe(O)(N4Py)]2+, a new designed iron-carbene complex [Fe(O)(N4Py)]2+ was theoretically designed. The geometric and electronic structures of [Fe(O)(N4Py)]2+ were studied via density functional theory and B3LYP method, and the [Fe(O)(N4Py)]2+ catalytic properties versus cyclohexane were investigated. The calculation results show that the energy of the quintet spin state of [Fe(O)(N4Py)]2+ is ca. 4.8 kJ/mol higher than that of the triplet ground state, suggesting that the quintet spin state can hardly participate in the reaction. The N-heterocyclic carbene (NHC) equatorial ligand was found to have stronger σ-donating and greater steric hindrance than N4Py ligand, indicating that the complex [Fe(O)(N4Py)]2+ is more stable than [Fe(O)(N4Py)]2+ complex. Moreover, on the triplet spin surface, the energy barrier of [Fe(O)(N4Py)]2+ has higher activation energy than that of [Fe(O)(N4Py)]2+ by 2.0 kJ/mol via a single-state reactivity pattern, implying that [Fe(O)(N4Py)]2+ complex is more reactive than [Fe(O)(N4Py)]2+ complex.

Key words: Non-heme, N-Heterocyclic carbene, Density functional theory, Orbital coefficient, Reaction mechanism

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