【摘要】 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%.更多还原

【Abstract】 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 mole-cules to form a surface-confined aniline dimer,4’-mercapto-N-phenylquinone diimine (HSC6H4NC6H4NH,NPQD) by the head-to-tail coupling. 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 fre-quencies 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%,indicating the existence of the surface-confined species of NPQD.更多还原