An impact of the ring substitution in nicorandil on its adsorption on silver nanoparticles. Surface-enhanced Raman spectroscopy studies

• Surface-enhanced Raman spectra of nicorandil and 1-methylnicorandil are studied.
• Substituents in the ring nitrogen atom lead to changes in the orientation of the silver.
• Similarities and differences in SERS profile of each pyridinium species are discussed in detail.

The substituent effect on structure and surface activity of biologically active nicorandil was investigated by means of surface-enhanced Raman spectroscopy (SERS). Vibrational characterization was a basis for investigation of the adsorption profile of nicorandil and 1-methylnicorandil on silver nanoparticles. An assignment of SERS bands was performed by the comparison of the Raman spectra of both compounds in the solid state and in solutions, complemented by DFT calculations. Even though the nitro group was found to be the most attractive to the silver surface, the strong impact of the methyl substituent changed this preferable adsorption mechanism in 1-methylnicorandil. Protonation of the nitrogen atom in the pyridinium ring was also found to have an impact on absorption mechanism.

Figure optionsDownload as PowerPoint slide