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pH‐dependent surface‐enhanced Raman scattering studies of N ‐acetylalanine monolayers self‐assembled on a silver surface
Author(s) -
Yang Haifeng,
Zhu Jun,
Sheng Chun,
Sun Xiaojing,
Ji Jiahua,
Ma Xiaoling
Publication year - 2007
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1740
Subject(s) - monolayer , carboxylate , imine , amide , raman scattering , chemistry , adsorption , density functional theory , raman spectroscopy , deprotonation , protonation , metal , organic chemistry , computational chemistry , ion , biochemistry , physics , optics , catalysis
Monolayers of N ‐acetylalanine on a metallic surface can serve as a biocompatible functional interface to construct biosensors. In the present paper, the surface‐enhanced Raman scattering (SERS) spectra of N ‐acetylalanine monolayers self‐assembled on a silver surface under different pH were recorded. Assignments of the obtained spectra were carried out by density functional theory (DFT) calculations (BLYP/6‐311G). On the basis of the SERS effect, the nature of adsorption of N ‐acetylalanine on a silver surface was deduced. It can be concluded that the fully protonated N ‐acetylalanine is adsorbed on the silver surface via the imine group together with the carboxylate group, while it anchored onto the surface not only through both the imine and the carboxylate groups but also through the amide group after being completely deprotonated in the basic solution. Copyright © 2007 John Wiley & Sons, Ltd.