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On the road from formamide ices to nucleobases: IR-spectroscopic observation of a direct reaction between cyano radicals and formamide in a high-energy impact event.
Ferus, Martin; Civis, Svatopluk; Mládek, Arnost; Sponer, Jirí; Juha, Libor; Sponer, Judit E.
Afiliación
  • Ferus M; J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejskova 3, CZ-182 23 Prague 8, Czech Republic.
J Am Chem Soc ; 134(51): 20788-96, 2012 Dec 26.
Article en En | MEDLINE | ID: mdl-23193998
The formamide-based synthesis of nucleic acids is considered as a nonaqueous scenario for the emergence of biomolecules from inorganic matter. In the current study, we scrutinized the chemical composition of formamide ices mixed with an FeNi meteorite material treated with laser-induced dielectric breakdown plasma created in nitrogen buffer gas. These experiments aimed to capture the first steps of those chemical transformations that may lead to the formation of nucleobases during the impact of an extraterrestrial icy body containing formamide on an early Earth atmosphere. High-resolution FT-IR spectroscopy combined with quantum chemical calculations was used to analyze the volatile fraction of the products formed during such an event. We have found that the spectrum of the evaporated formamide ices is dominated by the spectral signatures of the dimeric form of formamide. Upon exposure to laser sparks, new well-defined bands appear in the spectrum centered at ~820, ~995, and ~1650 cm(-1). On the basis of quantum chemical calculations, these bands can be assigned to the absorptions of 2-amino-2-hydroxy-acetonitrile and to 2-amino-2-hydroxy-malononitrile, which are formed in a direct reaction between formamide and CN(•) radicals upon the high-energy impact event. We also show that there is an exergonic reaction route via these intermediates leading to diaminomaleonitrile, which is generally considered to play a key role in the synthesis of nucleobases.
Asunto(s)

Texto completo: 1 Colección: 01-internacional Banco de datos: MEDLINE Asunto principal: Ácidos Nucleicos / Cianuros / Medio Ambiente Extraterrestre / Formamidas / Radicales Libres / Hielo Idioma: En Revista: J Am Chem Soc Año: 2012 Tipo del documento: Article País de afiliación: República Checa

Texto completo: 1 Colección: 01-internacional Banco de datos: MEDLINE Asunto principal: Ácidos Nucleicos / Cianuros / Medio Ambiente Extraterrestre / Formamidas / Radicales Libres / Hielo Idioma: En Revista: J Am Chem Soc Año: 2012 Tipo del documento: Article País de afiliación: República Checa