INTERACTIONS OF CYTIDINE DERIVATIVES WITH METALS AS REVEALED BY SURFACE-ENHANCED RAMAN-SPECTROSCOPY

Surface-enhanced Raman spectra of cytidine and cytidine 5'-monophosphate adsorbed on copper and silver colloids were investigated. As an aid to the interpretation with regard to the metal-adsorbate binding sites, the normal Raman spectra of the complexes of these substances with the metal ions were also obtained. The adsorption of the cytosine moiety in these substances occurs preferentially through the carbonyl bond, the pyrimidine ring adopting a non-planar orientation on the surface. However, in the complexes involving the metal ions the N-3 position is found to be the site through which the base interacts with these metals. The ribofuranose ring does not seem to participate significantly in the interaction of these substances with copper and silver in either the colloidal or ionic states.