Effect of substituents on the excited-state dynamics of the modified DNA bases 2,4-diaminopyrimidine and 2,6-diaminopurine

0351245 - ÚOCHB 2011 RIV GB eng J - Článek v odborném periodiku
Gengeliczki, Z. - Callahan, M. P. - Svadlenak, N. - Pongor, C. I. - Sztáray, B. - Meerts, L. - Nachtigallová, Dana - Hobza, Pavel - Barbatti, M. - Lischka, Hans - Vries de, M. S.
Effect of substituents on the excited-state dynamics of the modified DNA bases 2,4-diaminopyrimidine and 2,6-diaminopurine.
Physical Chemistry Chemical Physics. Roč. 12, č. 20 (2010), s. 5375-5388. ISSN 1463-9076. E-ISSN 1463-9084
Grant CEP: GA MŠMT LC512
Výzkumný záměr: CEZ:AV0Z40550506
Klíčová slova: excited-state lifetime * IR/UV double-resonant spectroscopy * multi-reference ab initio methods * modified DNA bases
Kód oboru RIV: CF - Fyzikální chemie a teoretická chemie
Impakt faktor: 3.454, rok: 2010

To explore the excited state dynamics of pyrimidine derivatives, we performed a combined experimental and theoretical study. We present resonant two-photon ionization and IR-UV double resonance spectra of 2,4-diaminopyrimidine and 2,6-diaminopurine. For 2,4-diaminopyrimidine, we observed only the diamino tautomer with an excited state lifetime bracketed between 10 ps and 1 ns. For 2,6-diaminopurine, we observed two tautomers with ns excited state lifetimes. We investigated the nature of the excited state of 2,4-diaminopyrimidine by means of multi-reference ab initio methods. The calculations of stationary points in the ground and excited states, minima on the S0/S1 crossing seam and connecting reaction paths show that several paths with negligible barriers exist, allowing ultrafast radiationless deactivation if excited at energies slightly higher than the band origin. The sub-nanosecond lifetime found experimentally is in good agreement with this finding.
Trvalý link: http://hdl.handle.net/11104/0191041