Cryogenic IR and UV spectroscopy of isomer-selected cytosine radical cation
Oxidation of the nucleobases is of great concern for the stability of DNA strands and is considered as a source of mutagenesis and cancer. However, precise spectroscopy data, in particular in their electronic excited states are scarce if not missing. We here report an original way to produce isomer-...
| Autores: | , , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2022 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/218029 |
| Acceso en línea: | http://hdl.handle.net/11336/218029 |
| Access Level: | acceso abierto |
| Palabra clave: | Cryogenic Ions UV spectroscopy DFT TD-DFT IR spectroscopy action spectroscopy https://purl.org/becyt/ford/1.4 https://purl.org/becyt/ford/1 |
| Sumario: | Oxidation of the nucleobases is of great concern for the stability of DNA strands and is considered as a source of mutagenesis and cancer. However, precise spectroscopy data, in particular in their electronic excited states are scarce if not missing. We here report an original way to produce isomer-selected radical cations of DNA bases, exemplified in the case of cytosine, through the photodissociation of cold cytosine-silver (C-Ag+) complex. IR-UV dip spectroscopy of C-Ag+ features fingerprint bands for the two keto-amino cytosine tautomers. UV photodissociation (UVPD) of the isomer-selected C-Ag+ complexes produces the cytosine radical cation (C˙+) without isomerization. IR-UV cryogenic ion spectroscopy of C˙+ allows for the unambiguous structural assignment of the two keto-amino isomers of C˙+. UVPD spectroscopy of the isomer-selected C˙+ species is recorded at a unique spectral resolution. These benchmark spectroscopic data of the electronic excited states of C˙+ are used to assess the quantum chemistry calculations performed at the TD-DFT, CASSCF/CASPT2 and CASSCF/MRCI-F12 levels. |
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