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Multiple Decay Mechanisms and 2D‐UV Spectroscopic Fingerprints of Singlet Excited Solvated Adenine‐Uracil Monophosphate

The decay channels of singlet excited adenine uracil monophosphate (ApU) in water are studied with CASPT2//CASSCF:MM potential energy calculations and simulation of the 2D‐UV spectroscopic fingerprints with the aim of elucidating the role of the different electronic states of the stacked conformer i...

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Autores principales: Li, Quansong, Giussani, Angelo, Segarra‐Martí, Javier, Nenov, Artur, Rivalta, Ivan, Voityuk, Alexander A., Mukamel, Shaul, Roca‐Sanjuán, Daniel, Garavelli, Marco, Blancafort, Lluís
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5021121/
https://www.ncbi.nlm.nih.gov/pubmed/27113273
http://dx.doi.org/10.1002/chem.201505086
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author Li, Quansong
Giussani, Angelo
Segarra‐Martí, Javier
Nenov, Artur
Rivalta, Ivan
Voityuk, Alexander A.
Mukamel, Shaul
Roca‐Sanjuán, Daniel
Garavelli, Marco
Blancafort, Lluís
author_facet Li, Quansong
Giussani, Angelo
Segarra‐Martí, Javier
Nenov, Artur
Rivalta, Ivan
Voityuk, Alexander A.
Mukamel, Shaul
Roca‐Sanjuán, Daniel
Garavelli, Marco
Blancafort, Lluís
author_sort Li, Quansong
collection PubMed
description The decay channels of singlet excited adenine uracil monophosphate (ApU) in water are studied with CASPT2//CASSCF:MM potential energy calculations and simulation of the 2D‐UV spectroscopic fingerprints with the aim of elucidating the role of the different electronic states of the stacked conformer in the excited state dynamics. The adenine (1)L(a) state can decay without a barrier to a conical intersection with the ground state. In contrast, the adenine (1)L(b) and uracil S(U) states have minima that are separated from the intersections by sizeable barriers. Depending on the backbone conformation, the CT state can undergo inter‐base hydrogen transfer and decay to the ground state through a conical intersection, or it can yield a long‐lived minimum stabilized by a hydrogen bond between the two ribose rings. This suggests that the (1)L(b), S(U) and CT states of the stacked conformer may all contribute to the experimental lifetimes of 18 and 240 ps. We have also simulated the time evolution of the 2D‐UV spectra and provide the specific fingerprint of each species in a recommended probe window between 25 000 and 38 000 cm(−1) in which decongested, clearly distinguishable spectra can be obtained. This is expected to allow the mechanistic scenarios to be discerned in the near future with the help of the corresponding experiments. Our results reveal the complexity of the photophysics of the relatively small ApU system, and the potential of 2D‐UV spectroscopy to disentangle the photophysics of multichromophoric systems.
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spelling pubmed-50211212016-09-23 Multiple Decay Mechanisms and 2D‐UV Spectroscopic Fingerprints of Singlet Excited Solvated Adenine‐Uracil Monophosphate Li, Quansong Giussani, Angelo Segarra‐Martí, Javier Nenov, Artur Rivalta, Ivan Voityuk, Alexander A. Mukamel, Shaul Roca‐Sanjuán, Daniel Garavelli, Marco Blancafort, Lluís Chemistry Full Papers The decay channels of singlet excited adenine uracil monophosphate (ApU) in water are studied with CASPT2//CASSCF:MM potential energy calculations and simulation of the 2D‐UV spectroscopic fingerprints with the aim of elucidating the role of the different electronic states of the stacked conformer in the excited state dynamics. The adenine (1)L(a) state can decay without a barrier to a conical intersection with the ground state. In contrast, the adenine (1)L(b) and uracil S(U) states have minima that are separated from the intersections by sizeable barriers. Depending on the backbone conformation, the CT state can undergo inter‐base hydrogen transfer and decay to the ground state through a conical intersection, or it can yield a long‐lived minimum stabilized by a hydrogen bond between the two ribose rings. This suggests that the (1)L(b), S(U) and CT states of the stacked conformer may all contribute to the experimental lifetimes of 18 and 240 ps. We have also simulated the time evolution of the 2D‐UV spectra and provide the specific fingerprint of each species in a recommended probe window between 25 000 and 38 000 cm(−1) in which decongested, clearly distinguishable spectra can be obtained. This is expected to allow the mechanistic scenarios to be discerned in the near future with the help of the corresponding experiments. Our results reveal the complexity of the photophysics of the relatively small ApU system, and the potential of 2D‐UV spectroscopy to disentangle the photophysics of multichromophoric systems. John Wiley and Sons Inc. 2016-04-26 2016-05-23 /pmc/articles/PMC5021121/ /pubmed/27113273 http://dx.doi.org/10.1002/chem.201505086 Text en © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs (http://creativecommons.org/licenses/by-nc-nd/4.0/) License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.
spellingShingle Full Papers
Li, Quansong
Giussani, Angelo
Segarra‐Martí, Javier
Nenov, Artur
Rivalta, Ivan
Voityuk, Alexander A.
Mukamel, Shaul
Roca‐Sanjuán, Daniel
Garavelli, Marco
Blancafort, Lluís
Multiple Decay Mechanisms and 2D‐UV Spectroscopic Fingerprints of Singlet Excited Solvated Adenine‐Uracil Monophosphate
title Multiple Decay Mechanisms and 2D‐UV Spectroscopic Fingerprints of Singlet Excited Solvated Adenine‐Uracil Monophosphate
title_full Multiple Decay Mechanisms and 2D‐UV Spectroscopic Fingerprints of Singlet Excited Solvated Adenine‐Uracil Monophosphate
title_fullStr Multiple Decay Mechanisms and 2D‐UV Spectroscopic Fingerprints of Singlet Excited Solvated Adenine‐Uracil Monophosphate
title_full_unstemmed Multiple Decay Mechanisms and 2D‐UV Spectroscopic Fingerprints of Singlet Excited Solvated Adenine‐Uracil Monophosphate
title_short Multiple Decay Mechanisms and 2D‐UV Spectroscopic Fingerprints of Singlet Excited Solvated Adenine‐Uracil Monophosphate
title_sort multiple decay mechanisms and 2d‐uv spectroscopic fingerprints of singlet excited solvated adenine‐uracil monophosphate
topic Full Papers
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5021121/
https://www.ncbi.nlm.nih.gov/pubmed/27113273
http://dx.doi.org/10.1002/chem.201505086
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