This seminar is part of the EAI on-line seminars
The presentation will provide an overview of recent studies on low-temperature reactions, which are expected to lead to the formation of complex organic and biologically significant molecules in the interstellar medium. It will focus on the following questions. How large biomolecules can be formed already in space? Can the processes occurring in space affect the origin of life on Earth? We review our recent experimental study of the reactivity of carbon atoms and show the possible chemical pathways leading to the formation of organic and biological molecules in space. Few reactions pathways were suggested for the formation of glycine at low temperature. The first one is C + H2 → HCH followed by NH3 + HCH + CO2 → glycine. The second one is C + NH3 → CH2NH followed by CH2NH + CO + H2O → glycine or CH2NH + CO2 + H2 → glycine. The condensation of atomic carbon on the surface of cold solid particles (cosmic dust) in translucent molecular clouds could also lead to the formation of proteins. The barrierless reaction between CO, C, and NH3 reactants leads to the formation of monomeric fragments of polyglycine (NH2CH=C=O – aminoketene). Moreover, these fragments further polymerize effectively producing polypeptides. This polypeptide synthesis proceeds via a novel pathway that skips the stage of amino acid formation and is efficient even at low temperatures without energetic processing or the presence of water. Since, the chemistry involves three of the most abundant species (CO, C, and NH3) present in star-forming molecular clouds, the amount of peptides or even proteins formed in this way in space could be notable. Therefore, the delivery of the molecules found in our experiments to rocky planets might play an important role in the origins of life.