物理化学学报 >> 2008, Vol. 24 >> Issue (08): 1471-1476.doi: 10.3866/PKU.WHXB20080824

研究论文 上一篇    下一篇

巯基偶氮苯单分子电子传输的取代基效应

罗世霞; 张笑一; 张思亭; 朱淮武; 胡继伟; 卫钢   

  1. 贵州师范大学理学院, 贵阳 550001; 贵州省山地环境信息系统和生态环境保护重点实验室, 贵阳 550001; CSIRO Materials Science and Engineering, PO Box 218, Lindfield, NSW2070, Australia
  • 收稿日期:2008-04-14 修回日期:2008-05-19 发布日期:2008-08-06
  • 通讯作者: 张笑一 E-mail:chemlsx@163.com

Influence of Substituents on Electron Transport through the Single-Molecule Mercapto-Azobenzene

LUO Shi-Xia; ZHANG Xiao-Yi; ZHANG Si-Ting; ZHU Huai-Wu; HU Ji-Wei; WEI Gang   

  1. School of Physics and Chemistry, Guizhou Normal University, Guiyang 550001, P. R. China; Guizhou Provincial Key Laboratory for Information System of Mountainous Areas and Protection of Ecological Environment, Guiyang 550001, P. R. China; CSIRO Materials Science and Engineering, PO Box 218, Lindfield, NSW2070, Australia
  • Received:2008-04-14 Revised:2008-05-19 Published:2008-08-06
  • Contact: ZHANG Xiao-Yi E-mail:chemlsx@163.com

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摘要： 用密度泛函理论B3LYP/6-31G**计算巯基偶氮苯分子及分子离子的空间构型和电子结构, 研究取代基对巯基偶氮苯单分子电子传输的影响. 结果表明, 拉电子基(—COOH、—NO2)的引入, 可以提高巯基偶氮苯单分子电子传输体系的稳定性, 使体系LUMO的离域性增高、S原子反应活性增强、HOMO-LUMO能隙显著减小, 进而降低电子传输能垒, 有利于分子电子传输. 相同取代基的分子离子比分子具有更小的HOMO-LUMO能隙, S—Au键更易形成, 金属-分子-金属结构的电子传输性更强.

关键词: 巯基偶氮苯, 电子传输, 密度泛函理论, 电子结构

Abstract: The influence of substituents on electron transport through single-molecule mercapto-azobenzene were investigated by using density functional theory (DFT) B3LYP/6-31G** to calculate the geometry and electronic structure changes. With the introduction of electron-withdrawing group (—COOH or —NO2) into single-molecule mercapto-azobenzene, the calculation results showed that the electron transporting stability increased, the delocalization effect of LUMO rose, the reactivity of sulfur atomincreased and HOMO-LUMOgap (HLG) decreased evidently; which led to a decrease in the energy gap of electron transport and a rise in the electron transport abilities. Comparing molecular ion with its molecule, it could be found that the HLG of the molecular ion decreased further, S—Au bond was easier to form, and electron transfer took placemore easily through the systemof metal-molecule-metal.

Key words: Mercapto-azobenzene, Electron transport, Density functional theory, Electron Structure