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The Role of 1πσ* States in the Formation of Adenine Radical-Cations in DNA Duplexes

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The Role of 1πσ* States in the Formation of Adenine Radical-Cations in DNA Duplexes. / Karsili, Tolga N V; Marchetti, Barbara; Ashfold, Michael N R .

In: Chemical Physics, Vol. 515, 14.11.2018, p. 464-471.

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Karsili, Tolga N V ; Marchetti, Barbara ; Ashfold, Michael N R . / The Role of 1πσ* States in the Formation of Adenine Radical-Cations in DNA Duplexes. In: Chemical Physics. 2018 ; Vol. 515. pp. 464-471.

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@article{b6bf16feeb744936b0237cea90e2f4bd,
title = "The Role of 1πσ* States in the Formation of Adenine Radical-Cations in DNA Duplexes",
abstract = "Photoinduced damage of DNA is a well-known but still far from fully understood phenomenon. Electronic structure methods are here employed to investigate potential roles of πσ∗ states in initiating photodamage, and ways in which πσ∗-state driven photochemistry might evolve with increasing molecular complexity. The study starts with the bare 9H-adenine molecule and progresses through to a model double-helix DNA duplex in aqueous solution. Relative to the gas phase, aqueous solvation is predicted to stabilize the 1πσ∗ states of these systems when exciting at the respective ground state equilibrium geometries, but to have relatively little effect on the asymptotic NH bond strengths. But the study also re-emphasises the potential importance of rival σ∗ ← π excitations, wherein a solute π electron is promoted to a σ∗ orbital localized on an OH bond of a complexing H2O molecule, as a route to forming parent radical cations – as have recently been observed following near UV photoexcitation of double-helix adenine-thymine duplexes in water (Banyasz et al., 2018). The subsequent deprotonation of such radical cations offers a rival low energy route to NH bond fission and radical formation in such duplexes.",
author = "Karsili, {Tolga N V} and Barbara Marchetti and Ashfold, {Michael N R}",
year = "2018",
month = "11",
day = "14",
doi = "10.1016/j.chemphys.2018.08.016",
language = "English",
volume = "515",
pages = "464--471",
journal = "Chemical Physics",
issn = "0301-0104",
publisher = "North-Holland Publishing Company",

}

RIS - suitable for import to EndNote

TY - JOUR

T1 - The Role of 1πσ* States in the Formation of Adenine Radical-Cations in DNA Duplexes

AU - Karsili, Tolga N V

AU - Marchetti, Barbara

AU - Ashfold, Michael N R

PY - 2018/11/14

Y1 - 2018/11/14

N2 - Photoinduced damage of DNA is a well-known but still far from fully understood phenomenon. Electronic structure methods are here employed to investigate potential roles of πσ∗ states in initiating photodamage, and ways in which πσ∗-state driven photochemistry might evolve with increasing molecular complexity. The study starts with the bare 9H-adenine molecule and progresses through to a model double-helix DNA duplex in aqueous solution. Relative to the gas phase, aqueous solvation is predicted to stabilize the 1πσ∗ states of these systems when exciting at the respective ground state equilibrium geometries, but to have relatively little effect on the asymptotic NH bond strengths. But the study also re-emphasises the potential importance of rival σ∗ ← π excitations, wherein a solute π electron is promoted to a σ∗ orbital localized on an OH bond of a complexing H2O molecule, as a route to forming parent radical cations – as have recently been observed following near UV photoexcitation of double-helix adenine-thymine duplexes in water (Banyasz et al., 2018). The subsequent deprotonation of such radical cations offers a rival low energy route to NH bond fission and radical formation in such duplexes.

AB - Photoinduced damage of DNA is a well-known but still far from fully understood phenomenon. Electronic structure methods are here employed to investigate potential roles of πσ∗ states in initiating photodamage, and ways in which πσ∗-state driven photochemistry might evolve with increasing molecular complexity. The study starts with the bare 9H-adenine molecule and progresses through to a model double-helix DNA duplex in aqueous solution. Relative to the gas phase, aqueous solvation is predicted to stabilize the 1πσ∗ states of these systems when exciting at the respective ground state equilibrium geometries, but to have relatively little effect on the asymptotic NH bond strengths. But the study also re-emphasises the potential importance of rival σ∗ ← π excitations, wherein a solute π electron is promoted to a σ∗ orbital localized on an OH bond of a complexing H2O molecule, as a route to forming parent radical cations – as have recently been observed following near UV photoexcitation of double-helix adenine-thymine duplexes in water (Banyasz et al., 2018). The subsequent deprotonation of such radical cations offers a rival low energy route to NH bond fission and radical formation in such duplexes.

U2 - 10.1016/j.chemphys.2018.08.016

DO - 10.1016/j.chemphys.2018.08.016

M3 - Article

VL - 515

SP - 464

EP - 471

JO - Chemical Physics

JF - Chemical Physics

SN - 0301-0104

ER -