Raman structural study of thymine and its 2′-deoxy-ribosyl derivatives in solid state, aqueous solution and when adsorbed on silver nanoparticles

Abstract

The structures of thymine, 2′-deoxythymidine (dT), 5′-thymidinemonophosphate (TMP) and the anti-HIV drug 3′-azido-3′-deoxythymidine (AZT) are studied in this work in solid state, aqueous solution and when these molecules are adsorbed on Ag colloids by means of Raman and surface-enhanced Raman spectroscopy (SERS). The presence of a ribosyl group in the thymine N(1) position induces a change in the electrodynamical properties of the corresponding nucleosides and nucleotides of this base resulting in a different adsorption on the metal. In addition, the presence of substituents such as phosphate in TMP and azido group in AZT influences significantly the conformation of these molecules in solid state, in aqueous solution and adsorbed on the metal surface, as well as the orientation that they adopt on the metal. The molecular conformation of these thymine derivatives has an important significance because of the relationship existing between structure and biological activity.