Vibrational spectra of adenine and deuterium-substituted analogues

New Raman and IR spectra have been recorded for adenine and its analogues substituted with deuterium on the nitrogen atoms, on the carbon at position 8 and on both. The bands observed have been assigned on the basis of experimental data and a normal coordinate analysis. The latter was carried out by means of a Urey-Bradley force field comparable to that already established for guanine. Assignments are discussed in the light of observed and calculated frequencies and isotopic shifts. (author)