Multiple decay mechanisms and 2D-UV spectroscopic fingerprints of singlet excited solvated adenine-uracil monophosphate
Author(s)
Type
Journal Article
Abstract
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 1La state can decay without a barrier to a conical intersection with the ground state. In contrast, the adenine 1Lb 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 1Lb, 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.
Date Issued
2016-05-18
Date Acceptance
2016-04-26
Citation
Chemistry - A European Journal, 2016, 22 (22), pp.7497-7507
ISSN
0947-6539
Publisher
Wiley
Start Page
7497
End Page
7507
Journal / Book Title
Chemistry - A European Journal
Volume
22
Issue
22
Copyright Statement
© 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 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.
This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs 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.
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000379727900027&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Physical Sciences
Chemistry, Multidisciplinary
Chemistry
ab initio calculations
DNA
molecular electronics
photophysics
UV/Vis spectroscopy
2-DIMENSIONAL ELECTRONIC SPECTROSCOPY
FOURIER-TRANSFORM SPECTROSCOPY
ULTRAFAST INTERNAL-CONVERSION
LIGHT-HARVESTING COMPLEX
AB-INITIO SIMULATIONS
STATE DYNAMICS
BASE-STACKING
MOLECULAR-DYNAMICS
NUCLEIC-ACIDS
1ST-PRINCIPLES SIMULATION
Publication Status
Published
Date Publish Online
2016-04-26