Raman spectroscopic study of 6-amino-7-deazapurine

Abstract

We used Raman spectroscopy to perform an adsorption study on 6-amino-7-deazapurine (6A-7DAP) on gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs). Unlike the adenine purine unit, the 6A-7DAP ring does not have a nitrogen atom in its N7 position. Density functional theory (DFT) calculations predicted that the amino-9H tautomeric form would be most stable among the conformers of 6A-7DAP including amino and imino conformers. Surface-enhanced Raman scattering spectra were analyzed with appropriate vibrational assignments to estimate the binding modes based on DFT calculations. After considering the enhancement factors, the Raman spectra of adenine and 6A-7DAP on AgNPs and AuNPs were dissimilar, suggesting that the different nitrogen atoms of the adenine and 6A-7DAP molecule may be significantly involved in the binding on AgNPs and AuNPs. Our Raman study indicates that the purine analog nitrogen atoms’ positions may play a significant role in coordinating metal surfaces.