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Title: Heterocyclic anions of astrobiological interest

As more complex organic molecules are detected in the interstellar medium, the importance of heterocyclic molecules to astrobiology and the origin of life has become evident. 2-Aminothiazole and 2-aminooxazole have recently been suggested as important nucleotide precursors, highlighting azoles as potential prebiotic molecules. This study explores the gas-phase chemistry of three deprotonated azoles: oxazole, thiazole, and isothiazole. For the first time, their gas-phase acidities are experimentally determined with bracketing and H/D exchange techniques, and their reactivity is characterized with several detected interstellar neutral molecules (N{sub 2}O, O{sub 2}, CO, OCS, CO{sub 2}, and SO{sub 2}) and other reactive species (CS{sub 2}, CH{sub 3}Cl, (CH{sub 3}){sub 3}CCl, and (CH{sub 3}){sub 3}CBr). Rate constants and branching fractions for these reactions are experimentally measured using a modified commercial ion trap mass spectrometer whose kinetic data are in good accord with those of a flowing afterglow apparatus reported here. Last, we have examined the fragmentation patterns of these deprotonated azoles to elucidate their destruction mechanisms in high-energy environments. All experimental data are supported and complemented by electronic structure calculations at the B3LYP/6-311++G(d,p) and MP2(full)/aug-cc-pVDZ levels of theory.
Authors:
; ;  [1] ;  [2] ;  [3]
  1. Department of Chemistry and Biochemistry, 215 UCB, University of Colorado, Boulder, CO 80309 (United States)
  2. Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019 (United States)
  3. Department of Astrophysical and Planetary Sciences, 391 UCB, University of Colorado, Boulder, CO 80309 (United States)
Publication Date:
OSTI Identifier:
22348395
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 779; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; AFTERGLOW; CARBON DIOXIDE; CARBON MONOXIDE; CARBON SULFIDES; COSMOLOGY; FRAGMENTATION; INTERSTELLAR SPACE; MASS SPECTROMETERS; METHYL CHLORIDE; MOLECULES; NITROUS OXIDE; SPACE; STARS; SULFUR DIOXIDE; TRAPS