Optical absorption and magnetic circular dichroism spectra of thiouracils: a quantum mechanical study in solution

L. Martínez-Fernández , Tobias Fahleson, Patrick Norman, Fabrizio Santoro, Sonia Coriani, Roberto Improta

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Abstract

The excited electronic states of 2-thiouracil, 4-thiouracil and 2,4-dithiouracil, the analogues of uracil where the carbonyl oxygens are substituted by sulphur atoms, have been investigated by computing the magnetic circular dichroism (MCD) and one-photon absorption (OPA) spectra at the time-dependent density functional theory level. Special attention has been paid to solvent effects, included by a mixed discrete/continuum model, and to determining how our results depend on the adopted DFT functional (CAM-B3LYP and B3LYP). Whereas including solvent effects does not dramatically impact the MCD and OPA spectra, though improving the agreement with the experimental spectra, the performances of CAM-B3LYP and B3LYP are remarkably different. CAM-B3LYP captures well the effect of thionation on the uracil excited states and provides spectra in good agreement with the experiments, whereas B3LYP shows some deficiency in describing 2-TU and 2,4-DTU spectra, despite being more accurate than CAM-B3LYP for 4-TU.
Original languageEnglish
JournalPhotochemical & Photobiological Sciences
Volume16
Issue number9
Pages (from-to)1415-1423
ISSN1474-905X
DOIs
Publication statusPublished - 2017

Cite this

Martínez-Fernández , L. ; Fahleson, Tobias ; Norman, Patrick ; Santoro, Fabrizio ; Coriani, Sonia ; Improta, Roberto. / Optical absorption and magnetic circular dichroism spectra of thiouracils: a quantum mechanical study in solution. In: Photochemical & Photobiological Sciences. 2017 ; Vol. 16, No. 9. pp. 1415-1423.
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abstract = "The excited electronic states of 2-thiouracil, 4-thiouracil and 2,4-dithiouracil, the analogues of uracil where the carbonyl oxygens are substituted by sulphur atoms, have been investigated by computing the magnetic circular dichroism (MCD) and one-photon absorption (OPA) spectra at the time-dependent density functional theory level. Special attention has been paid to solvent effects, included by a mixed discrete/continuum model, and to determining how our results depend on the adopted DFT functional (CAM-B3LYP and B3LYP). Whereas including solvent effects does not dramatically impact the MCD and OPA spectra, though improving the agreement with the experimental spectra, the performances of CAM-B3LYP and B3LYP are remarkably different. CAM-B3LYP captures well the effect of thionation on the uracil excited states and provides spectra in good agreement with the experiments, whereas B3LYP shows some deficiency in describing 2-TU and 2,4-DTU spectra, despite being more accurate than CAM-B3LYP for 4-TU.",
author = "L. Mart{\'i}nez-Fern{\'a}ndez and Tobias Fahleson and Patrick Norman and Fabrizio Santoro and Sonia Coriani and Roberto Improta",
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Optical absorption and magnetic circular dichroism spectra of thiouracils: a quantum mechanical study in solution. / Martínez-Fernández , L.; Fahleson, Tobias; Norman, Patrick; Santoro, Fabrizio; Coriani, Sonia; Improta, Roberto.

In: Photochemical & Photobiological Sciences, Vol. 16, No. 9, 2017, p. 1415-1423.

Research output: Contribution to journalJournal articleResearchpeer-review

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T1 - Optical absorption and magnetic circular dichroism spectra of thiouracils: a quantum mechanical study in solution

AU - Martínez-Fernández , L.

AU - Fahleson, Tobias

AU - Norman, Patrick

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AU - Coriani, Sonia

AU - Improta, Roberto

PY - 2017

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AB - The excited electronic states of 2-thiouracil, 4-thiouracil and 2,4-dithiouracil, the analogues of uracil where the carbonyl oxygens are substituted by sulphur atoms, have been investigated by computing the magnetic circular dichroism (MCD) and one-photon absorption (OPA) spectra at the time-dependent density functional theory level. Special attention has been paid to solvent effects, included by a mixed discrete/continuum model, and to determining how our results depend on the adopted DFT functional (CAM-B3LYP and B3LYP). Whereas including solvent effects does not dramatically impact the MCD and OPA spectra, though improving the agreement with the experimental spectra, the performances of CAM-B3LYP and B3LYP are remarkably different. CAM-B3LYP captures well the effect of thionation on the uracil excited states and provides spectra in good agreement with the experiments, whereas B3LYP shows some deficiency in describing 2-TU and 2,4-DTU spectra, despite being more accurate than CAM-B3LYP for 4-TU.

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