Prebiotic molecules formation through the gas-phase reaction between HNO and CH₂CHOH₂⁺

¹ Computational Chemistry Group, Departamento de Química Física y Química InorgánicaFacultad de Ciencias, Universidad de Valladolid, 47011 Valladolid, Spain
e-mail: predondo@qf.uva.es
² Computational Chemistry Group, Departamento de Química Orgánica, Escuela de Ingenierías Industriales, Universidad de Valladolid, 47011 Valladolid, Spain

Received: 17 May 2017
Accepted: 15 June 2017

Abstract

Context. Knowing how the molecules that are present in the ISM can evolve to more complex ones is an interesting topic in interstellar chemistry. The study of possible reactions between detected species can help to understand the evolution in complexity of the interstellar matter and also allows knowing the formation of new molecules which could be candidates to be detected. We focus our attention on two molecules detected in space, vinyl alcohol (CH₂CHOH) and azanone (HNO).

Aims. We aim to carry out a theoretical study of the ion-molecule reaction between protonated vinyl alcohol and azanone. The viability of formation of complex organic molecules (COMs) from these reactants is expected to provide some insight into the formation of prebiotic species through gas phase reactions.

Methods. The reaction of protonated vinyl alcohol with azanone has been theoretically studied by using ab initio methods. Stationary points on the potential energy surface (PES) were characterized at the second-order Moller-Plesset level in conjunction with the aug-cc-pVTZ (correlation-consistent polarized valence triple-zeta) basis set. In addition, the electronic energies were refined by means of single-point calculations at the CCSD(T) level (coupled cluster single and double excitation model augmented with a non-iterative treatment of triple excitations) with the same basis set.

Results. From a thermodynamic point of view, twelve products, composed of carbon, oxygen, nitrogen, and hydrogen which could be precursors in the formation of more complex biological molecules, can be obtained from this reaction. Among these, we focus especially on ionized glycine and two of its isomers. The analysis of the PES shows that only formation of cis- and trans-O-protonated imine acetaldehyde, CH₂NHCOH⁺ and, CHNHCHOH⁺, are viable under interstellar conditions.

Conclusions. The reaction of protonated vinyl alcohol with azanone can evolve in the interstellar medium to more complex organic molecules of prebiotic interest. Our results suggest that imine acetaldehyde could be a feasible candidate molecule to be searched for in space.