Infra-red absorption spectra of pyrimidine nucleotides in H 2O and D 2O solution

Abstract

Infra-red absorption spectra of several pyrimidine nucleosides and nucleotides have been obtained in H 2O and in D 2O solution. By correlation of the appearance and disappearance of absorption bands upon variation of the pH of these solutions with the known dissociation constants of amine, enolic, and phosphate groups, the assignment of bands to specific atomic groups has been greatly facilitated. Assignments are presented for various ionic phosphate frequencies, bond stretching and deformation frequencies, frequencies associated with amine-ammonium and keto-enol transitions, and frequencies associated with certain conjugated ring structures. Evidence is presented indicating the existence of strong intra-molecular hydrogen bonds. These data are correlated with previous infra-red and ultra-violet absorption and X-ray diffraction data pertaining to these compounds.