Pure rotational spectrum of 2-pyridone⋯water and quantum chemical calculations on the tautomeric equilibrium 2-pyridone⋯water/2-hydroxypyridine⋯water

Maris, Assimo; Ottaviani, Paolo; Camináti, Walther

doi:10.1016/s0009-2614(02)00785-6

Cited by 44 publications

(66 citation statements)

References 24 publications

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“…26). Both adducts present similar hydrogen bond structures which are also comparable to those observed for related complexes, such as formamide-water [180][181][182] Nmethylformamide-water [183], or 2-pyridone-water [184], as could be expected given the similar natures of the hydrogen bonds in all these systems.…”

Section: Uracil Thymine and Their Monohydratessupporting

confidence: 80%

Microwave Spectroscopy of Biomolecular Building Blocks

Alonso

López

2014

Topics in Current Chemistry

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Microwave spectroscopy, considered as the most definitive gas phase structural probe, is able to distinguish between different conformational structures of a molecule, because they have unique spectroscopic constants and give rise to distinct individual rotational spectra.Previously, application of this technique was limited to molecular specimens possessing appreciable vapor pressures, thus discarding the possibility of studying many other molecules of biological importance, in particular those with high melting points, which had a tendency to undergo thermal reactions, and ultimately degradation, upon heating.Nowadays, the combination of laser ablation with Fourier transform microwave spectroscopy techniques, in supersonic jets, has enabled the gas-phase study of such systems. In this chapter, these techniques, including broadband spectroscopy, as well as results of their application into the study of the conformational panorama and structure of biomolecular building blocks, such as amino acids, nucleic bases, and monosaccharides, are briefly discussed, and with them, the tools for conformational assignation - rotational constants, nuclear quadrupole coupling interaction, and dipole moment.

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Section: Uracil Thymine and Their Monohydratessupporting

confidence: 80%

Microwave Spectroscopy of Biomolecular Building Blocks

Alonso

López

2014

Topics in Current Chemistry

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“…The tautomeric equilibrium of 2HP/2PO is shifted to 2HP for the isolated species but predicted to favor the keto form when the molecules interact with water. [24][25][26][27] Now that the hydrated complexes of both tautomers have been experimentally observed, we can ascertain whether the predicted reversal in stability takes place. We examined first the 2HP/2PO equilibrium and estimated the relative abundances of the tautomers from relative intensity measurements.…”

Section: Discussionmentioning

confidence: 99%

“…One monohydrated complex attributed to the keto tautomer, 2PO-H 2 O, had already been investigated by millimeter wave spectroscopy. 26 Therefore, its experimental rotational constants were used to predict the transitions of this complex in the frequency range of our spectrometer. Rotational transitions of µ a -and µ b -type were easily identified and measured.…”

Section: Rotational Spectramentioning

confidence: 99%

Tautomerism and Microsolvation in 2-Hydroxypyridine/2-Pyridone

et al. 2010

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The Fourier transform microwave spectra of the hydrated forms of the tautomeric pair 2-pyridinone/2-hydroxypyridine (2PO/2HP) have been investigated in a supersonic expansion. Three hydrated species, 2PO-H₂O, 2HP-H₂O, and 2PO-(H₂O)₂, have been observed in the rotational spectrum. Each molecular complex was confidently identified by the features of the ¹⁴N quadrupole hyperfine structure of the rotational transitions. The presence of water affects the tautomeric equilibrium -N═C(OH)- ↔ -NH-C(═O)-, which is shifted to the enol form for the bare molecules 2PO/2HP but to the keto tautomer for the hydrated forms.

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“…In this respect, it is quite interesting to investigate the tautomerization of PY to HY by using molecular clusters as a microscopic model for the environment. Most ab initio calculations 28,[30][31][32][33][34] to date have focused on the hydrogen-bonding interactions between the two tautomers and the water molecule or the spectra studies of them; only a few studies 23, 24,29 have attempted to examine the proton-transfer mechanism of PY to HY. Field and Hiller 23 have used the 3-21G basis incorporating the CI expansion to investigate the proton-transfer mechanism of PY to HY.…”

Section: Introductionmentioning

confidence: 99%

Density Functional Study on the Reaction Mechanism of Proton Transfer in 2-Pyridone: Effect of Hydration and Self-Association

et al. 2005

J. Phys. Chem. A

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The proton-transfer mechanism in the isolated, mono, dehydrated forms and dimers of 2-pyridone and the effect of hydration or self-assistance on the transition state structures corresponding to proton transfer from the keto form to the enol form have been investigated using B3LYP and BH-LYP hybrid density functional methods at the 6-311++G (2d, 2p) basis set level. The barrier heights for both H2O-assisted and self-assisted reactions are significantly lower than that of the bare tautomerization reaction from 2-pyridone to 2-hydroxypyridine, implying the importance of the superior catalytic effect of H2O and (H2O)2 and the important role of 2-pyridone itself for the intramolecular proton transfer. Long-range solvent effects have also been taken into account by using the continuum model (Onsager model and polarizable continuum model (PCM)) of water. The tautomerization energies and the potential energy barriers are increased both for the water-assisted and for the self-assisted reaction because of the bulk solvent, which imply that the tautomerization of PY becomes less favorable in the polar solvent.

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Pure rotational spectrum of 2-pyridone⋯water and quantum chemical calculations on the tautomeric equilibrium 2-pyridone⋯water/2-hydroxypyridine⋯water

Cited by 44 publications

References 24 publications

Microwave Spectroscopy of Biomolecular Building Blocks

Microwave Spectroscopy of Biomolecular Building Blocks

Tautomerism and Microsolvation in 2-Hydroxypyridine/2-Pyridone

Density Functional Study on the Reaction Mechanism of Proton Transfer in 2-Pyridone: Effect of Hydration and Self-Association

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