Description
A full conformational study of solid-state anhydrous adenine is reported, using vibrational spectroscopy
techniques coupled to DFT calculations, for the isolated molecule and the solid. In both cases, the N9Hamino
tautomer was found to be the predominant species, followed by the N7H-amino form. An excellent
agreement was achieved between experiment and theory, both for wavenumbers and intensities (without
the need for scaling). A complete spectral assignment was performed, since all vibrational spectroscopic
techniques were available to this study – FTIR, Raman and INS – allowing us to detect and interpret even
the lowest frequency vibrational bands, not previously accessed. The quantum mechanical calculations presently
carried out represent the highest theoretical level applied so far to the study of nucleobases. The authors acknowledge financial support from the Portuguese
Foundation for Science and Technology – PEst-OE/QUI/
UI0070/2011. The INS work was supported by the European
Commission under the 7th Framework Programme through the
Key Action: Strengthening the European Research Area,
Research Infrastructures (Contract no: CP-CSA_INFRA-2008-
1.1.1 Number 226507-NMI3).
; Valero, Rosendo 
