Formation of Nitrogen-Bearing Organic Molecules in the Reaction NH + C2H5: A Theoretical Investigation and Main Implications for Prebiotic Chemistry in Space

The synthesis of nitrogen-containing organic molecules is a crucial step in prebiotic chemistry, as they are potential precursors of important biological molecules such as nucleobases and amino acids. In this respect, unsaturated species like nitriles (containing a -CN group) or imines (containing a carbon-nitrogen double bond) are particularly interesting because the presence of an unsaturated bond allows for further evolution. Interestingly, simple species belonging to both nitrile and imine families have been detected in the interstellar medium and in the upper atmosphere of Titan. In this contribution, the reaction between the imidogen radical (NH) and ethyl radical (C2H5) is investigated from a theoretical point of view to establish whether it can form product species with a novel C-N bond. According to the present electronic structure calculations of the stationary points of the C2H6N potential energy surface, the NH + C2H5 reaction is a viable route of formation of methanimine and ethanimine, that is, two N-containing molecules already detected in the interstellar medium.