Photochemistry of 2-Aminooxazole, a Hypothetical Prebiotic Precursor of RNA Nucleotides
| Autoři | |
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| Rok publikování | 2013 |
| Druh | Článek v odborném periodiku |
| Časopis / Zdroj | Journal of Physical Chemistry Letters |
| Fakulta / Pracoviště MU | |
| Citace | |
| www | http://pubs.acs.org/doi/abs/10.1021/jz401315e |
| Doi | http://dx.doi.org/10.1021/jz401315e |
| Obor | Fyzikální chemie a teoretická chemie |
| Klíčová slova | EXCITED-STATE DYNAMICS; REPULSIVE (1)PI-SIGMA-ASTERISK STATES; CONICAL INTERSECTIONS; BUILDING-BLOCKS; AB-INITIO; PYRROLE; MOLECULES; SYSTEMS; PHOTOPHYSICS; DRIVEN |
| Popis | 2-Aminooxazole has recently been proposed as a hypothetical precursor of RNA nucleotides on early earth. UV irradiation was considered as a crucial environmental factor in the proposed reaction sequence. We report on state-of-the-art multireference quantum-chemical calculations elucidating the possible nonradiative deactivation channels of this compound. According to our findings, the gas-phase photochemistry of 2-aminooxazole should be dominated by the photodetachment of the hydrogen atom of the NH2 group via a (1)pi sigma(NH)* state leading either to ultrafast nonradiative deactivation, phototautomerization, or photodissociation of a hydrogen atom. We also identified a possible ring-opening reaction and a ring-puckering process that could occur after electronic excitation. These reactions seem to be less probable because they are driven by a higher-lying excited singlet state and are inherently slower than the hydrogen-atom dynamics. |
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