Acta Phys. -Chim. Sin. ›› 1998, Vol. 14 ›› Issue (09): 772-777.doi: 10.3866/PKU.WHXB19980902

• ARTICLE • Previous Articles     Next Articles

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
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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