Publication details

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

Authors

FERUS Martin CIVIS Svatopluk MLÁDEK Arnošt ŠPONER Jiří JUHA Libor ŠPONEROVÁ Judit

Year of publication 2012
Type Article in Periodical
Magazine / Source Journal of the American Chemical Society
MU Faculty or unit

Central European Institute of Technology

Citation
Web http://pubs.acs.org/doi/abs/10.1021/ja310421z
Doi http://dx.doi.org/10.1021/ja310421z
Field Biophysics
Keywords HIGH-POWER LASER; APPROXIMATE COULOMB POTENTIALS; INDUCED DIELECTRIC-BREAKDOWN; AUXILIARY BASIS-SETS; VIBRATIONAL FREQUENCIES; GAS-MIXTURES; INFORMATIONAL POLYMERS; EMISSION-SPECTROSCOPY; NA+-MONTMORILLONITE; PREBIOTIC SYNTHESIS
Attached files
Description 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 similar to 820, similar to 995, and similar to 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.
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