Skip to content

Ionic Pathway Inducing Peptide Bond Formation in the Interstellar Medium

Christian Alcaraz (Senior Researcher), Claire Romanzin (Associate Prof), Roland Thissen (Senior Researcher), Nicolas Solem (PhD Student)

This research focuses on studying the reactions of CH3COOH+• and COOH+ with methylamine (CH3NH2) through a combined theoretical/experimental approach. Set within an astrochemical context, the study explores the possibility of forming a C(O)-N bond analogous to the peptide bond, relating to the formation of prebiotic molecules. The experimental results obtained with the CERISES instrument reveal for the first time, in addition to typical reaction pathways such as proton transfer, hydride transfer, or charge transfer processes, the formation of a new chemical bond between the cation and the amine.

The theoretical approach allows for the identification of a two-step reaction mechanism: (i) the formation of a barrierless reaction intermediate through a simple association mechanism, and (ii) a rearrangement of the reaction intermediate leading to the loss of a radical or a molecule (specifically CH3• or H2O for CH3COOH+• and COOH+, respectively). Although this process is very minor compared to other reaction pathways, it does not require any energy input. We investigate the dependence of these reactive processes on the internal energy of the reacting ion and the collision energy. Subsequently, we plan to study the effect of adding one or more water molecules to the reactive system, which could potentially promote the formation of this bond.

Evidence of peptide bond formation in the gas phase through the reaction of formic acid ions and methylamine. [Derbali2021]

Collaborations

Emilie Zins (MONARIS, Sorbonne Univ., Paris)