Surface-Enhanced Raman Spectra of Pyridine and Pyrazine Adsorbed on a Au(210) Single-Crystal Electrode

Surface-enhanced Raman scattering (SERS) spectra of pyrazine and pyridine adsorbed on an “unroughened” Au(210) electrode surface have been obtained for the first time. The SERS spectra indicate that both pyridine and pyrazine adsorb on the Au(210) electrode via their nitrogen lone pairs (end-on configuration). The integrated SERS intensities from the ring-breathing vibrations (ca. 1010 cm-1 for pyridine and 1019 cm-1 for pyrazine) were measured. The potential profiles (integrated SERS intensity versus potential plots) were compared to the surface coverage data, obtained electrochemically, for the adsorption of pyridine and pyrazine on Au(210). No simple relationship was found between the SERS intensities and the surface coverage data; however, it seems that the SERS intensities track the surface coverage for low surface concentrations (less than a monolayer).