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.

J Heyrovský Institute of Physical Chemistry Academy of Sciences of the Czech Republic Dolejškova 3 CZ 182 23 Prague 8 Czech Republic

Citace poskytuje Crossref.org

Infrared Spectra of Small Radicals for Exoplanetary Spectroscopy: OH, NH, CN and CH: The State of Current Knowledge

A Computational Quantum-Based Perspective on the Molecular Origins of Life's Building Blocks

An Innovative Approach for the Generation of Species of the Interstellar Medium

High Energy Radical Chemistry Formation of HCN-rich Atmospheres on early Earth

Formation of nucleobases in a Miller-Urey reducing atmosphere

TiO2-catalyzed synthesis of sugars from formaldehyde in extraterrestrial impacts on the early Earth

High-energy chemistry of formamide: a unified mechanism of nucleobase formation