TY - JOUR
T1 - Variable temperature FTIR spectra of polycrystalline purine nucleobases and estimating strengths of individual hydrogen bonds
AU - Rozenberg, M.
AU - Fausto, R.
AU - Reva, I.
N1 - Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2021/4/15
Y1 - 2021/4/15
N2 - In the first part of this work, we report the FTIR spectra of pure NH and isotopically substituted ND (10–15% D and 80–90% D) polycrystalline hypoxanthine, xanthine, adenine and guanine recorded in the 400–4000 cm−1 range, as a function of temperature (10–300 K). We provide assignments of the stretching and out-of-plane bending amine (NH2) and imine (NH) bands to the distinct H-bonds present in the crystal, based on the temperature sensitivity and isotopic exchange behavior. Empirical correlations between spectral and thermodynamic or structural parameters enabled us to estimate the energies and lengths of H-bonds in the studied nucleobase crystals and to correlate them with literature data. The empirical H-bonding energies are compared with H-bonding and stacking energies computed for hypoxanthine. In the second part, strategies for using the empirical correlations together with information extracted from quantum mechanical data (in particular from the Bader's quantum theory of atoms in molecules, QTAIM) for the evaluation of hydrogen bonding properties are discussed, and their advantages and drawbacks pointed out. The justification for a cooperative use of quantum-mechanical calculations with empirical spectra-energy correlations is discussed.
AB - In the first part of this work, we report the FTIR spectra of pure NH and isotopically substituted ND (10–15% D and 80–90% D) polycrystalline hypoxanthine, xanthine, adenine and guanine recorded in the 400–4000 cm−1 range, as a function of temperature (10–300 K). We provide assignments of the stretching and out-of-plane bending amine (NH2) and imine (NH) bands to the distinct H-bonds present in the crystal, based on the temperature sensitivity and isotopic exchange behavior. Empirical correlations between spectral and thermodynamic or structural parameters enabled us to estimate the energies and lengths of H-bonds in the studied nucleobase crystals and to correlate them with literature data. The empirical H-bonding energies are compared with H-bonding and stacking energies computed for hypoxanthine. In the second part, strategies for using the empirical correlations together with information extracted from quantum mechanical data (in particular from the Bader's quantum theory of atoms in molecules, QTAIM) for the evaluation of hydrogen bonding properties are discussed, and their advantages and drawbacks pointed out. The justification for a cooperative use of quantum-mechanical calculations with empirical spectra-energy correlations is discussed.
KW - Adenine
KW - Guanine
KW - Hydrogen bonding
KW - Hypoxanthine
KW - Spectra-structure empirical correlations
KW - Xanthine
UR - http://www.scopus.com/inward/record.url?scp=85099800381&partnerID=8YFLogxK
U2 - 10.1016/j.saa.2020.119323
DO - 10.1016/j.saa.2020.119323
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C2 - 33508682
AN - SCOPUS:85099800381
SN - 1386-1425
VL - 251
JO - Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy
JF - Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy
M1 - 119323
ER -