Quantum chemical studies of solvent effects on cytosine tautomers

Sathyabama, V.; Anandan, K.; Kanagaraju, R.

doi:10.1016/j.theochem.2008.11.035

Cited by 9 publications

(12 citation statements)

References 39 publications

(52 reference statements)

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“…Our DFT calculations are in good agreement with those reported in the literature [39-42, 47, 49]. However, it should be mentioned here that the percentage contents of major and minor forms depend on the level of calculations [38][39][40][41][42][43][44][45][46][47][48][49][50] as well as on the experimental method applied [30][31][32][33][34][35][36]. For example, the DFT methods predict the canonical tautomer C2 as the favored form for neutral cytosine, whereas the HF, MPn and CC methods indicate the C1a isomer.…”

Section: Resultssupporting

confidence: 90%

“…The common conclusion on its major tautomers (C2 and C1a) in the gas phase has not yet been formulated. The microhydration by one, two, or three water molecules [42,45,46] and the macrohydration by using the continuum models [40,41,45,48,49] favor the 'canonical' tautomer C2.…”

Section: Resultsmentioning

confidence: 99%

“…In aqueous solution, two tautomeric forms of cytosine (C2 and C3) seem to dominate [37]. Unfortunately, the complete tautomeric mixture of cytosine has not been investigated by quantum chemical methods [38][39][40][41][42][43][44][45][46][47][48][49][50]. Maximum six tautomers have been studied for neutral cytosine (C1-C3, C5, C6, and C8), and the amide-iminol and amine-imine conversions analyzed [40][41][42].…”

Section: Tautomermentioning

confidence: 99%

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DFT studies on the favored and rare tautomers of neutral and redox cytosine

Raczyńska

Sapuła²,

Zientara‐Rytter³

et al. 2015

Struct Chem

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The complete tautomeric mixture consisting of nine prototropic tautomers has been studied in the gas phase at the DFT(B3LYP)/6-311?G(d,p) level for neutral, oxidized, and reduced cytosine. Rotational isomerism of the exo -OH group and geometrical isomerism of the exo =NH group have also been considered. Tautomeric conversions possible for cytosine have been compared with those for its structural models, 4-amino-and 2-hydroxypyrimidine. Effects of intramolecular interactions between neighboring groups for cytosine are analogous to those observed for model compounds. Although they are not very strong, they are sufficient to influence tautomeric equilibria and relative stabilities of individual tautomers. One-electron oxidation and one-electron reduction change tautomeric preferences. Tautomers that are rare forms for neutral cytosine become favored ones for oxidized and reduced cytosine. Aromaticity is not the main factor that dictates the tautomeric preferences. Stability of functional groups seems to be more important than full electron delocalization.

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Section: Resultssupporting

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Section: Tautomermentioning

confidence: 99%

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DFT studies on the favored and rare tautomers of neutral and redox cytosine

Raczyńska

Sapuła²,

Zientara‐Rytter³

et al. 2015

Struct Chem

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“…Because of the additional dipole moment induced by the solvent's reaction field, a polar molecule will have a large dipole moment in a polar solvent than in the gas phase. Thus, the dipole moment of form VI increases greatly in ethanol solution, which in turn will increase the stability of the form VI 19.…”

Section: Resultsmentioning

confidence: 99%

New insight into the photochromic mechanism of 1,3‐diphenyl‐4‐(4‐fluoro)benzal‐5‐pyrazolone N(4)‐phenyl semicarbazone

Yang¹,

Wu²,

Jia³

et al. 2011

Int J of Quantum Chemistry

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Density functional theory (DFT) calculation has been carried out to investigate the photochromic mechanism of 1,3-diphenyl-4-(4-fluoro)benzal-5-pyrazolone N(4)-phenyl semicarbazone. The novel mechanism, proposed by us, has different reaction pathway between the forward and the reverse process. The energy barrier of the forward direction was calculated to be significantly larger than that of the reverse direction (30.35 kcal/mol to 9.88 kcal/mol), which confirms the experimental observation that the forward process needs irradiation of light while the reverse one will take place easily when heated. The solvent effect on the relative stabilities of those isomers that may involve in the reaction has also been investigated by applying the polarizable continuum model (PCM) of the self-consistent reaction field theory.

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“…Despite the fact that cytosine may exist in various tautomeric forms, we will focus on keto-amino structure (see Fig. 2), which is presumably the most stable one in the gas phase [2].…”

Section: Introductionmentioning

confidence: 99%

Density functional theory (DFT) prediction of structural and spectroscopic parameters of cytosine using harmonic and anharmonic approximations

2015

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The applicability of popular and efficient B3LYP hybrid density functional and medium-size Popletype basis set in combination with computationally expensive anharmonic model to obtain more accurate theoretical structure, vibrational frequencies and GIAO NMR parameters of cytosine was tested. We report on prediction of cytosine equilibrium (R e) and rovibrationally averaged (R v) structures and vibrational frequencies in the gas phase and DMSO solution using density functional theory combined with 6-311??G** basis set. The harmonic and anharmonic vibrational frequencies (using second-order vibrational perturbation theory, VPT2) were critically discussed. In comparison with initial harmonic data, a significantly better agreement between scaled and anharmonic frequencies and experiment was observed. Proton and carbon nuclear magnetic shieldings were calculated at R e and R v structures of cytosine in the gas phase and DMSO solution using BHandH and B3LYP density functionals combined with 6-311??G**, aug-cc-pVTZ-J and STO-3G mag basis sets. The obtained NMR results were compared with available experimental data and discussed at length.

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Quantum chemical studies of solvent effects on cytosine tautomers

Cited by 9 publications

References 39 publications

DFT studies on the favored and rare tautomers of neutral and redox cytosine

DFT studies on the favored and rare tautomers of neutral and redox cytosine

New insight into the photochromic mechanism of 1,3‐diphenyl‐4‐(4‐fluoro)benzal‐5‐pyrazolone N(4)‐phenyl semicarbazone

Density functional theory (DFT) prediction of structural and spectroscopic parameters of cytosine using harmonic and anharmonic approximations

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