化学学报 ›› 2007, Vol. 65 ›› Issue (17): 1741-1745.    下一篇

研究论文

4-氨基苯硫酚在金电极上电化学转变过程的表面增强拉曼光谱及其理论研究

孙如, 李淑瑾, 姚建林, 顾仁敖*   

  1. (苏州大学化学化工学院 苏州 215123)
  • 投稿日期:2007-02-12 修回日期:2007-03-30 发布日期:2007-09-14
  • 通讯作者: 顾仁敖

Surface Enhanced Raman Spectroscopy and Theoretical Studies on the Electrochemical Transformation Processes of 4-Aminothiophenol on Au Electrode

SUN Ru; LI Shu-Jin; YAO Jian-Lin; GU Ren-Ao*   

  1. (Department of Chemistry, Suzhou University, Suzhou 215123)
  • Received:2007-02-12 Revised:2007-03-30 Published:2007-09-14
  • Contact: GU Ren-Ao

采用循环伏安法和表面增强拉曼散射现场研究了酸性溶液中4-氨基苯硫酚(PATP)在金电极表面的电化学转变过程, 并结合密度泛函理论(DFT)对光谱进行了指认, 由此确定电极表面的最终产物. 研究结果表明, PATP分子在电极表面首先氧化为阳离子自由基, 该自由基与邻近的分子通过头尾相接生成二聚体4'-巯基-N-苯基苯醌二亚胺, 随后发生水解反应生成4'-巯基-N-苯基苯醌单亚胺. 用DFT在B3LYP/6-311+G** (C, N, S, H)/ LANL2DZ (Au)水平上计算模拟4'-巯基-N-苯基苯醌二亚胺在金表面的拉曼光谱, 结果与所获得的表面拉曼光谱较好吻合, 平均相对偏差约为2.1%.

关键词: 表面增强拉曼光谱, 密度泛函理论, 4-氨基苯硫酚, 电化学转变, 金电极

The electrochemical technique and in situ Fourier transfer surface enhanced Raman spectroscopy were employed to investigate the electrochemical transformation processes of 4-aminothiophenol (PATP) on Au electrode in an acidic solution. By assistance of density functional theory consideration, the surface Ra-man spectra were assigned and thus the final surface species on the electrode were proposed. The results re-vealed that PATP was oxidized to a cation radical firstly, which interacted with the adjacent PATP molecules to form a surface-confined aniline dimer, 4'-mercapto-N-phenylquinone diimine (HSC6H4NC6H4NH, NPQD) by the head-to-tail cou-pling. Following that, NPQD underwent the hydrolysis to yield 4'-mercapto-N-phenylquinone monoimine (HSC6H4NC6H4O, NPQM). Using the B3LYP density functional method with the 6-311+G** basis sets for C, N, S, H and LANL2DZ for gold, the calculated Raman frequencies of the NPQD molecules on Au surface were in good agreement with the spectral features of FT-SERS. The mean relative deviation (MRD) with experimental values is 2.1%, indi-cating the existence of the surface-confined species of NPQD.

Key words: surface enhanced Raman spectroscopy, density functional theory, 4-aminothiophenol, electrochemical transformation, gold electrode