A Vacuum Ultraviolet Photoionization Study on the Formation of N-methyl Formamide (HCONHCH₃) in Deep Space: A Potential Interstellar Molecule with a Peptide Bond

Abstract

As one of the simplest molecules containing a peptide bond, N-methyl formamide (HCONHCH 3) represents a potential key molecule involved in the peptide bond polymerization in extraterrestrial ices. Detected tentatively toward the star-forming region Sgr B2(N2), the synthetic pathways have previously been elusive. By exploiting isomer-selective detection of the reaction products via photoionization, coupled with reflectron time-of-flight mass spectrometry (PI-ReTOF-MS), we present compelling evidence for the formation of N-methyl formamide (HCONHCH 3) in astrochemically relevant ice mixtures of methylamine (CH 3 NH 2) and carbon monoxide (CO), upon irradiation with energetic electrons as generated in the track of galactic cosmic ray particles (GCRs) penetrating interstellar ices. As one of the simplest molecules containing a peptide bond (-CO-NH-), N-methyl formamide could represent a benchmark involved in radiation-induced peptide bond polymerization in extraterrestrial ices, and thus bring us closer to revealing where in the Universe the molecular precursors linked to the origins of life might have been synthesized.

C2H5NO Isomers: from Acetamide to1,2-Oxazetidine and Beyond

“…eV. 13 The comparable values obtained here for the lowest conformer are 149 kJ mol −1 and 9.39 eV -clearly not a valid comparison.…”

“…The conformer with cis Hs, technically this is the (Z ) conformer, is some 5.5 kJ mol −1 more stable than that with trans Hs or (E ) conformer in agreement with earlier work 59 and with a study of nitrogen species by a series of composite methods 60 where the difference was reported as 5.38 ± 0.8 kJ mol −1 at 298. in accord with all recent theoretical determinations, viz. this work 9.79 eV, Frigge et al 13 9.80 eV.…”

A theoretical investigation of the reaction between the amidogen, NH, and the ethyl, C2H5, radicals: a possible gas-phase formation route of interstellar and planetary ethanimine

“…In all cases, a possible conclusion is that, if no other, yet unexplored, formation routes of ethanimine are actually contributing, the observed ethanimine is mostly produced in the gas-phase (where the process is controlled by kinetics and provides almost identical populations of the two isomers), with a much smaller contribution from the grain-surface (where the thermal population of the ethanimine adsorbed on ice would be E-/Z-about 10^5 at 30 K). Alternatively, non-thermal ice chemistry could be at work (see, for instance,Frigge et al 2018 andBergner et al 2017). More constraints on the observation and additional experimental or theoretical data on the possible formation routes of the two isomers (such as the determination of the population of the two isomers in hydrogenation experiments of acetonitrile) are strongly needed to finally solve the puzzle.The results obtained for the title reaction are also of interest in the chemistry of the atmosphere of Titan, the massive moon of Saturn, which is characterized by a large fraction of nitrogen and a small percentage of methane and higher hydrocarbons.…”

Astrochemical Pathways to Complex Organic and Prebiotic Molecules: Experimental Perspectives for In Situ Solid-State Studies

“…Another COM considered to have great potential in prebiotic chemistry—since it is the simplest molecule containing a peptide bond, known to be the “bridge” connecting amino acids in proteins and polypeptides—is formamide (NH 2 HCO). This species has been formed in several processing experiments of solid-state mixtures containing key astrophysical ices such as H 2 O, CO, CH 4 , NH 3 , HCN, or CH 3 OH, irradiated by energetic ions (e.g., [ 89 , 90 ]) and electrons (e.g., [ 91 , 92 ]). Its astrophysical importance is given by the fact that formamide has already been detected in several astrophysical environments, such as molecular clouds, protostars (e.g., [ 10 , 16 ]) and cometary comae (e.g., [ 20 , 25 ]).…”