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Excited state properties of 5-formylcytosine and 5-hydroxymethylcytosine

TitleExcited state properties of 5-formylcytosine and 5-hydroxymethylcytosine
Publication TypeJournal Article
Year of Publication2017
AuthorsMato, J, Keipert, K, Gordon, MS
JournalMolecular Physics
Volume115
Pagination2721-2730
Date Published04
Type of ArticleArticle
ISBN Number0026-8976
Accession NumberWOS:000415075100010
Keywords5-formylcytosine, 5-hydroxymethylcytosine, chemistry, coupled-cluster, Cytosine, cytosine tautomers, dna, dynamics simulations, excitations, gas-phase, mechanisms, multireference, nucleic-acid bases, photochemistry, photoisomerization, physics, plesset perturbation-theory
Abstract

Excited state properties are investigated for two natural analogues of cytosine, 5-hydroxymethylcytosine (5hmC) and 5-formylcytosine (5fC). Excited state calculations using multi-reference perturbation theory (MR-MP2), equations of motion singles and doubles coupled cluster theory and time-dependent density functional theory within the Tamm-Dancoff approximation show that 5fC differs from cytosine in that the dark n pi* state localised on the formyl group is lower in energy than the bright pi pi* state. The singlet state ordering for 5hmC, on the other hand, matches that of cytosine, with the bright pi pi* state located lower in energy than the n pi* state. The potential energy surface of 5hmC was also examined. Upon excitation of 5hmC to the bright pi pi* state, MR-MP2 calculations show that the most likely decay mechanism involves the pi pi* state with a 0.27 eV barrier leading to a conical intersection with the ground state. The present calculations suggest that the n pi* state is unlikely to contribute to the decay mechanism of 5hmC. [GRAPHICS]

DOI10.1080/00268976.2017.1311424
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Short TitleMol. Phys.