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Low temperature FTIR spectra and hydrogen bonds in polycrystalline adenosine and uridine

Item Type:Article
Title:Low temperature FTIR spectra and hydrogen bonds in polycrystalline adenosine and uridine
Creators Name:Rozenberg, M. and Jung, C. and Shoham, G.
Abstract:FTIR spectra of polycrystalline samples of adenosine and uridine, pure and containing small (<10%) quantity of N(O)H or N(O)D groups, were measured in KBr pellets from 4000 to 400 cm -1 at temperatures from 300 to 20 K. For the first time, the bands of narrow isotopically decoupled proton stretching vibration {nu} 1 mode of NH and OH groups were found and assigned to ordered hydrogen bonds according to crystal structural data for both nucleosides. The FTIR adenosine spectra in the out-of-plane bending proton {nu} 4 mode range (lower than 1000 cm -1) of N(O)H groups revealed at low temperature at least twice more bands, than in the {nu} 1 range, which are influenced by isotopic exchange and (or) cooling. Almost all of them have their counterparts in the N(O)D substance spectrum with an isotopic frequency ratio of 1.30-1.40. These bands were assigned to the differently H-bound disordered NH and OH protons, which could not be seen with crystal structural methods. The energy and length of different H-bonds were estimated from peak positions of both mode bands (as the red shift of {nu} 1 or blue shift of {nu} 4 relatively free molecules) with well-established empirical correlations between spectral, thermodynamic and structural parameters of hydrogen bonds. The results were compared with independent experimental data.
Keywords:Adenosine, Uridine, H-Bonding in Solids, Low-Temperature FTIR, Isotopic Dilution
Source:Spectrochimica Acta, A Molecular and Biomolecular Spectroscopy
Publisher:Pergamon-Elsevier Science Ltd
Page Range:733-741
Date:February 2005
Official Publication:https://doi.org/10.1016/j.saa.2004.05.024
PubMed:View item in PubMed

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