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Exploring ultraviolet photoinduced charge-transfer dynamics in a model dinucleotide of guanine and thymine

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Exploring ultraviolet photoinduced charge-transfer dynamics in a model dinucleotide of guanine and thymine. / Duchi, Marta; O'Hagan, Michael; Kumar, Rhea; Bennie, Simon; Galan, Carmen; Curchod, Basile; Oliver, Thomas A A.

In: Physical Chemistry Chemical Physics, Vol. 21, No. 26, 03.07.2019, p. 14407-14417.

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@article{31593f37aabd4b80895134cf74cfebf6,
title = "Exploring ultraviolet photoinduced charge-transfer dynamics in a model dinucleotide of guanine and thymine",
abstract = "An understanding of the initial photoexcited states of DNA is essential to unravelling deleterious photoinduced chemical reactions and the intrinsic ultrafast photoprotection of the genetic code for all life. In our combined experimental and theoretical study, we have elucidated the primary non-radiative relaxation dynamics of a model nucleotide of guanine and thymine (2'-deoxyguanosine 3'-monophospate 5'-thymidine, d(GpT)) in buffered aqueous solution. Experimentally, we unequivocally demonstrate that the Franck-Condon excited states of d(GpT) are significantly delocalised across both nucleobases, and mediate d(G+pT–) exciplex product formation on an ultrafast (< 350 fs) timescale. Theoretical studies show that the nature of the vertical excited states are very dependent on the specific geometry of the dinucleotide, and dictate the degree of delocalised, charge-transfer or localised character. Our mechanism for prompt exciplex formation involves a rapid change in electronic structure and includes a diabatic surface crossing very close to the Franck-Condon region mediating fast d(G+pT–) formation. Exciplexes are quickly converted back to neutral ground state molecules on a ~10 ps timescale with a high quantum yield, ensuring the photostability of the nucleotide sequence.",
author = "Marta Duchi and Michael O'Hagan and Rhea Kumar and Simon Bennie and Carmen Galan and Basile Curchod and Oliver, {Thomas A A}",
year = "2019",
month = "7",
day = "3",
doi = "10.1039/C8CP07864E",
language = "English",
volume = "21",
pages = "14407--14417",
journal = "Physical Chemistry Chemical Physics",
issn = "1463-9076",
publisher = "The Royal Society of Chemistry",
number = "26",

}

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TY - JOUR

T1 - Exploring ultraviolet photoinduced charge-transfer dynamics in a model dinucleotide of guanine and thymine

AU - Duchi, Marta

AU - O'Hagan, Michael

AU - Kumar, Rhea

AU - Bennie, Simon

AU - Galan, Carmen

AU - Curchod, Basile

AU - Oliver, Thomas A A

PY - 2019/7/3

Y1 - 2019/7/3

N2 - An understanding of the initial photoexcited states of DNA is essential to unravelling deleterious photoinduced chemical reactions and the intrinsic ultrafast photoprotection of the genetic code for all life. In our combined experimental and theoretical study, we have elucidated the primary non-radiative relaxation dynamics of a model nucleotide of guanine and thymine (2'-deoxyguanosine 3'-monophospate 5'-thymidine, d(GpT)) in buffered aqueous solution. Experimentally, we unequivocally demonstrate that the Franck-Condon excited states of d(GpT) are significantly delocalised across both nucleobases, and mediate d(G+pT–) exciplex product formation on an ultrafast (< 350 fs) timescale. Theoretical studies show that the nature of the vertical excited states are very dependent on the specific geometry of the dinucleotide, and dictate the degree of delocalised, charge-transfer or localised character. Our mechanism for prompt exciplex formation involves a rapid change in electronic structure and includes a diabatic surface crossing very close to the Franck-Condon region mediating fast d(G+pT–) formation. Exciplexes are quickly converted back to neutral ground state molecules on a ~10 ps timescale with a high quantum yield, ensuring the photostability of the nucleotide sequence.

AB - An understanding of the initial photoexcited states of DNA is essential to unravelling deleterious photoinduced chemical reactions and the intrinsic ultrafast photoprotection of the genetic code for all life. In our combined experimental and theoretical study, we have elucidated the primary non-radiative relaxation dynamics of a model nucleotide of guanine and thymine (2'-deoxyguanosine 3'-monophospate 5'-thymidine, d(GpT)) in buffered aqueous solution. Experimentally, we unequivocally demonstrate that the Franck-Condon excited states of d(GpT) are significantly delocalised across both nucleobases, and mediate d(G+pT–) exciplex product formation on an ultrafast (< 350 fs) timescale. Theoretical studies show that the nature of the vertical excited states are very dependent on the specific geometry of the dinucleotide, and dictate the degree of delocalised, charge-transfer or localised character. Our mechanism for prompt exciplex formation involves a rapid change in electronic structure and includes a diabatic surface crossing very close to the Franck-Condon region mediating fast d(G+pT–) formation. Exciplexes are quickly converted back to neutral ground state molecules on a ~10 ps timescale with a high quantum yield, ensuring the photostability of the nucleotide sequence.

U2 - 10.1039/C8CP07864E

DO - 10.1039/C8CP07864E

M3 - Article

VL - 21

SP - 14407

EP - 14417

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

SN - 1463-9076

IS - 26

ER -