Effect of Ag+ on the Excited-State Properties of a Gas-Phase (Cytosine)2Ag+ Complex: Electronic Transition and Estimated Lifetime
Recently, DNA molecules have received great attention because of their potential applications in material science. One interesting example is the production of highly fluorescent and tunable DNA–Agn clusters with cytosine (C)-rich DNA strands. Here, we report the UV photofragmentation spectra of gas...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2014 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/31368 |
| Acceso en línea: | http://hdl.handle.net/11336/31368 |
| Access Level: | acceso abierto |
| Palabra clave: | Dna Bases Dna−Agn Cluster Excited State Metal-Mediated Base Pairs Photofragmentation Spectroscopy https://purl.org/becyt/ford/1.4 https://purl.org/becyt/ford/1 |
| Sumario: | Recently, DNA molecules have received great attention because of their potential applications in material science. One interesting example is the production of highly fluorescent and tunable DNA–Agn clusters with cytosine (C)-rich DNA strands. Here, we report the UV photofragmentation spectra of gas-phase cytosine···Ag+···cytosine (C2Ag+) and cytosine···H+···cytosine (C2H+) complexes together with theoretical calculations. In both cases, the excitation energy does not differ significantly from that of isolated cytosine or protonated cytosine, indicating that the excitation takes place on the DNA base. However, the excited-state lifetime of the C2H+ (τ = 85 fs), estimated from the bandwidth of the spectrum, is at least 2 orders of magnitude shorter than that of the C2Ag+ (τ > 5000 fs). The increased excited-state lifetime upon silver complexation is quite unexpected, and it clearly opens the question about what factors are controlling the nonradiative decay in pyrimidine DNA bases. This is an important result for the expanding field of metal-mediated base pairing and may also be important to the photophysical properties of DNA-templated fluorescent silver clusters. |
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