CIESC Journal ›› 2013, Vol. 64 ›› Issue (S1): 88-97.DOI: 10.3969/j.issn.0438-1157.2013.z1.013

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Effect of substituents and central metal ions on electronic structure and catalytic activity of porphyrins

CAO Meijuan, YU Yanmin, FU Haiyan, SHE Yuanbin   

  1. 1. Institute of Green Chemistry and Fine Chemicals, College of Environmental & Energy Engineering, Beijing University of Technology, Beijing 100124, China;
    2. Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission & Ministry of Education, College of Chemistry and Materials Science, South-Central University for Nationalities, Wuhan 430074, Hubei, China;
    3. College of Pharmacy, South-Central University for Nationalities, Wuhan 430074, Hubei, China
  • Received:2013-11-01 Revised:2013-11-10 Online:2013-12-30 Published:2013-12-30
  • Supported by:

    supported by the National Natural Science Fundation of China (21276006, 21036009, 21076004, 21205145, 21376010), the Funding Project for Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality (PHR 201107104) and the Talents Fund of South-Central University for Nationalities (YZZ12002, XTZ13002).

取代基及中心金属离子对卟啉电子结构及催化活性的影响

  

  1. 1. 北京工业大学环能学院绿色化学与精细化工研究所, 北京 100124;
    2. 中南民族大学化学与 材料科学学院催化材料科学国家民委-教育部共建暨湖北省重点实验室, 湖北 武汉 430074;
    3. 中南民族大学药学院, 湖北 武汉 430074
  • 通讯作者: 佘远斌
  • 作者简介:曹梅娟(1980—),女,博士研究生。
  • 基金资助:

    国家自然科学基金项目(21276006, 21036009, 21076004, 21205145, 21376010);北京市属市管高等学校人才强教计划项目(PHR 201107104);中南民族大学引进人才基金和中南民族大学团队项目 (YZZ12002, XTZ13002)。

Abstract: How to adjust the microstructure, macroproperties and function of prophyrins by tuning the substituents and central metal ions species has been the key and the challenge problem for designing the high activity and selectivity catalysts. It can provide important theoretical foundation for the accurate designing of metalloporphyrin catalysts to study the effects of the substituents and central metal ions on the electronic structure properties of porphyrins. In order to understand the relationship between microstructure and macro catalytic efficiency of porphyrins in essence, the electronic structures of metalloporphyrins with different substituents (—OCH3,—CH3,—H,—NO2) and different central metal ions (Mn,Fe,Co,Cu,Zn) were investigated using computational chemistry method based on density functional. The results indicated that the electron-withdrawing substituent (—NO2) lowered the levels of the highest occupied orbitals (HOMO) and lowest unoccupied orbital (LUMO) of metalloporphyrins. Whereas the electron-donating substitutes increased the levels of the HOMO and LUMO of metalloporphyrins. The central metal ions have an effect on the distribution of frontier molecular orbital. The frontier molecular orbitals of variant valence metalloporphyrins (Mn,Fe,Co) were mainly composed of 3 d orbital of metal ions, which facilitated the activation of dioxygen. The frontier molecular orbitals of invariant valence metalloporphyrins (Cu,Zn) were composed of large π bond from porphyrin ligands. The electrons could transport fluently in the large π bond, therefore the invariant valence metalloporphyrins also have the high activity. Fukui function suggested that the active sites of variant valence metalloporphyrins located on the central metal ions. Whereas the active sites of invariant valence metalloporphyrins might locate on the porphyrin ligands.

Key words: porphyrin, computational chemistry, electronic structure, catalysis, activity

摘要: 通过调变取代基及中心金属离子种类调控金属卟啉的微观分子结构和宏观性质与功能是设计高活性、高选择性的金属卟啉催化剂的关键及富有挑战性的课题。取代基和中心金属离子对金属卟啉电子结构性质的影响研究可为金属卟啉催化剂的精确设计提供重要的理论依据。采用基于密度泛函理论计算化学方法系统地研究了不同取代基(—OCH3、—CH3、—H、—NO2)及中心金属离子(Mn、Fe、Co、Cu、Zn)对卟啉电子结构性质的影响,试图从本质上理解金属卟啉微观结构和宏观催化性能的关系。结果表明,吸电子基—NO2总是降低金属卟啉的最高占据轨道(HOMO)和最低未占据轨道(LUMO)能级,而供电子基—CH3和—OCH3总是升高金属卟啉的HOMO和LUMO能级。变价金属(Mn、Fe、Co)卟啉的前线分子轨道主要由金属离子的3 d轨道组成,有利于活化分子氧。不变价金属(Cu、Zn)卟啉的前线分子轨道的成分为卟啉配体形成的大π键,电子流动性好,故不变价金属也有较高的催化活性。Fukui函数分析表明变价金属卟啉的活性中心位于中心金属离子,而不变价金属卟啉的活性中心可能在卟啉配体上。

关键词: 卟啉, 计算化学, 电子结构, 催化, 活性

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