Is the reaction between formic acid and protonated aminomethanol a possible source of glycine precursors in the interstellar medium?

Abstract

Context. One of the most interesting questions in interstellar chemistry concerns whether we can detect the basic building blocks of proteins in astronomical sources. In ascertaining whether amino acids could be possible interstellar molecules, a crucial point is how they could be synthesized in the interstellar medium. Aims. We do a theoretical study of the ion-molecule reaction involving protonated aminomethanol and formic acid to establish its viability in space. This ion-molecule reaction has been proposed by other authors as a possible way to produce glycine in the interstellar medium. Methods. The relevant stationary points on the potential energy surface of the reaction between protonated aminomethanol and formic acid have been theoretically studied by using ab initio methods. The second-order Moller-Plesset level was employed, in conjunction with the correlation-consistent polarized valence triple-zeta (cc-pVTZ) 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) on the MP2/cc-pVTZ geometries with the aug-cc-pVTZ basis set. Results. Formation of protonated glycine is an exothermic process; however, the process presents a net activation barrier that makes this reaction unfeasible under interstellar conditions. Conclusions. The reaction of protonated aminomethanol with formic acid does not seem to be a plausible source of interstellar glycine. This particular case is a clear example that a detailed study of the potential energy surface is needed to establish the relevance of a process in the interstellar medium.

Mapping observations of complex organic molecules around Sagittarius B2 with the ARO 12 m telescope

“…t-HCOOH is a key organic molecule as the carboxyl group (C(= O)OH) is one of the main functional groups of amino acids (the structural units of proteins). This species is involved in a chemical route leading to glycine, the simplest amino acid (Redondo, Largo & Barrientos 2015). ARO observations indicate that the spatial distribution of t-HCOOH extends to the eastern component and peaks at Sgr B2(N).…”

Rotational spectrum simulations of asymmetric tops in an astrochemical context

“…Its structural similarities to more complex, biologically important species such as amino acids give formic acid a distinctive role in the field of astrobiology. Indeed, chemical routes to form glycine from HCOOH have been explored since the 1970s (e.g., [111][112][113]). In the present work, we have obtained the spectroscopic parameters and simulated rotational spectra for the cis and trans rotamers of HCOOH.…”

Mapping Observations of complex organic molecules around Sagittarius B2 with ARO 12m telescope

“…Formic acid t-HCOOH: t-HCOOH is a key organic molecule as the carboxyl group (C(=O)OH) is one of the main functional groups of amino acids (the structural units of proteins). This species is involved in a chemical route leading to glycine, the simplest amino acid (Redondo et al 2015). ARO observations indicate that the spatial distribution of t-HCOOH extends to the eastern component and peaks at Sgr B2(N).…”