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

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 (CH 2 CHOH) 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 augcc-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, CH 2 NHCOH + 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.

Structure and spectroscopic properties of imine acetaldehyde: a possible interstellar molecule

“…Trans-NHCHCHOH + is 8.3 kcal mol −1 more stable than cis-NHCHCHOH + at the CCSD(T)/aug-cc-pVTZ//MP2/augcc-pVTZ level and the conversion barrier from the cis conformer into the most stable trans one is only of 0.4 kcal mol −1 (≈200 K). From these results, the main conclusion of the study (Redondo et al 2017) was that imine acetaldehyde, the neutral counterpart of O-protonated imine acetaldehyde, could be a feasible candidate molecule to be searched for in space.…”

“…In this context, and in order to study the viability of formation of complex organic molecules (COMs) through reaction between detected species, we have recently studied the ion-molecule reaction between azanone, HNO, and protonated vinyl alcohol, CH 2 CHOH + 2 (Redondo et al 2017). Azanone or nitroxyl, was the first molecule with NO bond, detected in the ISM.…”

“…Therefore, we considered the ion-molecule reaction between CH 2 CHOH + 2 and HNO. From this reaction 12 thermodynamically viable interstellar products were obtained (Redondo et al 2017). Even though, NH 2 CHCOOH + + H 2 and NH 2 CH 2 CO + + H 2 O were, in principle, the most favourable products (reaction enthalpies are −93.3 and −81.3 kcal mol −1 , respectively, at the CCSD(T)/augcc-pVTZ//MP2/aug-cc-pVTZ level); paths giving cis-and trans-O-protonated imine acetaldehyde (cis-NHCHCHOH + and trans-NHCHCHOH + ) were the most plausible from both a thermodynamic (largest exothermicity) and a kinetic (lowest energy barrier) point of view.…”

Organic residues in astrophysical ice analogues: Thermal processing of hydrogenated glyoxal ices under interstellar conditions

“…It is well established that many organic molecules originate from reactions occurring on the surface of interstellar dust grains which are mainly composed of silicate, amorphous carbon and organic species (Tielens and Allamandola 1987;Draine 2003;Demyk 2011). By focusing on the formation and evolution of organic molecules on the interstellar dust grains, theoretical and experimental studies (Kimura and Kitadai 2015;Enrique-Romero et al 2016;Redondo et. 2017;Oba et al 2019) aim to understand the appearance of life beginning by the formation of prebiotic molecules and their precursors such as sugars, amino acids or nucleic bases called "building blocks of life" (Kimura and Kitadai 2015).…”

Formation of interstellar cyanoacetamide: a rotational and computational study

“…In this context, it was concluded in several experimental studies (He et al 2015;Zheng & Kaiser 2010;Congiu et al 2012) that hydroxylamine, which is expected to be one of the main precursors of amino acids in space, could be generated in the solid phase and then desorbed through a temperature-induced process into the gas phase. However, exothermic ion-molecule reactions between positive ions and neutral molecules still play a crucial role in the synthesis of organic interstellar molecules in the gas phase (Barrientos et al 2012;Redondo et al 2014Redondo et al , 2015Redondo et al , 2017 because these processes tend to have negligible activation energy barriers. Thus, we have carried out an accompanying theoretical study, consisting of a full exploration of the potential energy surface (PES), to analyze the feasibility of a plausible gas-phase reaction as a source of protonated cyanoacetamide in the ISM and thereby disclose the corresponding neutral form as a candidate molecule to be searched for in the ISM.…”