物理化学学报 >> 1998, Vol. 14 >> Issue (09): 772-777.doi: 10.3866/PKU.WHXB19980902

研究论文 上一篇    下一篇

偶氮苯自组装单分子膜中长程电子转移机理

邵会波, 于化忠, 张浩力, 罗颖, 程广军, 刘忠范   

  1. 北京大学化学与分子工程学院,智能材料研究中心,北京 100871
  • 收稿日期:1997-06-13 修回日期:1997-08-10 发布日期:1998-09-15
  • 通讯作者: 刘忠范

State of the Tunneling Mechanism for Long Range Electron Transfer in Azobenzene Self-assembled Monolayers

Shao Hui-Bo, Yu Hua-Zhong, Zhang Hao-Li, Luo Ying, Cheng Guang-Jun, Liu Zhong-Fan   

  1. Center for Intelligent Materials Research(CIMR),College of Chemistry and Molecular Engineering,Peking University,Beijing 100871
  • Received:1997-06-13 Revised:1997-08-10 Published:1998-09-15
  • Contact: Liu Zhong-Fan

摘要:

利用自组装技术在金电极表面构造了具有不同前端链长度偶氮苯功能化的单分子膜体系:Au/S(CH2)nNHCO-?-N=N-?-OCH2CH3(n=2,3,4,6).研究结果表明,偶氮苯到金电极的表现电子转移速率随它们之间的距离长度的增加而呈指数性的下降趋势.基于Marcus电子隧穿理论,得到了此自组装膜体系的长程电子隧穿系数β=(1.35±0.2)/CH2在和可逆电活性分子自组装膜体系及理论计算相比较的基础上,从偶氮苯分子自组装膜结构与电子转移过程的关系角度对这一结果进行了分析和说明.

关键词: 偶氮苯, 自组装膜, 电子隧穿系数

Abstract:

The tunneling mechanism for long range electron transfer in azobenzene self-assembled mololayers on gold has been studied by electrochemical techniques. We have prepared for the first time a series of azobenzene-tethered alkanethiol monolayers on gold electrode surface with varied number of methylenes in the alkyl chain spacer (CH3CH2-4-?-N=N-?-C(O)NH (CH2)nSH/Au, n=2, 3, 4, 6). The apparent electron transfer rate constants kapp of azobenzcne to the underlying electrode are found to fall off exponentially with increasing the length of alkyl chain spacers. Theelectron tunneling constant βfor the electron transfer in the present system are estimated to be 1.35±0.20 per CH2 from the logarithmic kapp. versus n (number of methylenes in the alkyl chain spacer) plot.

Key words: Azobenzene, Self-assembled monolayers(SAMs), Electron tunneling constant