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Danho A, Mardyukov A, Schreiner PR. The enol of isobutyric acid. Chem Commun (Camb) 2024; 60:5161-5164. [PMID: 38639644 PMCID: PMC11080965 DOI: 10.1039/d4cc01140f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 04/15/2024] [Indexed: 04/20/2024]
Abstract
We present the gas-phase synthesis of 2-methyl-prop-1-ene-1,1-diol, an unreported higher energy tautomer of isobutyric acid. The enol was captured in an argon matrix at 3.5 K, characterized spectroscopically and by DFT computations. The enol rearranges likely photochemically to isobutyric acid and dimethylketene. We also identified propene, likely photochemically formed from dimethylketene.
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Affiliation(s)
- Akkad Danho
- Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, Giessen 35392, Germany.
| | - Artur Mardyukov
- Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, Giessen 35392, Germany.
| | - Peter R Schreiner
- Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, Giessen 35392, Germany.
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2
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Danho A, Mardyukov A, Schreiner PR. The enol of propionic acid. Chem Commun (Camb) 2023; 59:11524-11527. [PMID: 37672001 DOI: 10.1039/d3cc03711h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
We demonstrate the gas-phase synthesis of prop-1-ene-1,1-diol, the hitherto unreported higher energy tautomer of propionic acid. The enol was trapped in an argon matrix and characterized by IR and UV/Vis spectroscopy in combination with density functional theory computations. Upon photolysis, the enol rearranges to propionic acid and methylketene.
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Affiliation(s)
- Akkad Danho
- Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, Giessen 35392, Germany.
| | - Artur Mardyukov
- Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, Giessen 35392, Germany.
| | - Peter R Schreiner
- Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, Giessen 35392, Germany.
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3
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Ballotta B, Martínez-Núñez E, Rampino S, Barone V. New prebiotic molecules in the interstellar medium from the reaction between vinyl alcohol and CN radicals: unsupervised reaction mechanism discovery, accurate electronic structure calculations and kinetic simulations. Phys Chem Chem Phys 2023; 25:22840-22850. [PMID: 37584420 DOI: 10.1039/d3cp02571c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2023]
Abstract
Vinyl alcohol (VyA) and cyanide (CN) radicals are relatively abundant in the interstellar medium (ISM). VyA is the enolic tautomer of acetaldehyde and has two low-lying conformers, characterized by the syn or anti placement of hydroxyl hydrogen with respect to the double bond. In this paper, we present a gas-phase model of the barrierless reactions of both VyA's conformers with CN employing accurate quantum chemical computations in the framework of a master equation approach based on the transition state theory. Our results indicate that both VyA conformers feature a similar reactivity with CN, starting with a barrierless addition to the double bond and followed by different isomerization, dissociation, and/or hydrogen elimination steps. The rate constants computed for temperatures up to 600 K show that several reaction channels are open even under the harsh conditions of the ISM, with the favoured one providing the first feasible formation route of a prebiotic molecule not yet detected in the ISM, namely cyanoacetaldehyde. This finding suggests looking for cyanoacetaldehyde in regions where both VyA and CN have already been detected, like, e.g., Sagittarius B2N or G+0.693-0.027.
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Affiliation(s)
- Bernardo Ballotta
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126, Pisa, Italy.
| | - Emilio Martínez-Núñez
- Departamento de Química Física, Facultade de Química, Campus Vida, Universidade de Santiago de Compostela, Avenida das Ciencias s/n, 15782, Santiago de Compostela, Spain
| | - Sergio Rampino
- Università degli Studi di Padova, Dipartimento di Scienze Chimiche, Via Marzolo 1, 35131 Padova, Italy
| | - Vincenzo Barone
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126, Pisa, Italy.
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4
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Marks JH, Wang J, Kleimeier NF, Turner AM, Eckhardt AK, Kaiser RI. Prebiotic Synthesis and Isomerization in Interstellar Analog Ice: Glycinal, Acetamide, and Their Enol Tautomers. Angew Chem Int Ed Engl 2023; 62:e202218645. [PMID: 36702757 DOI: 10.1002/anie.202218645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/23/2023] [Accepted: 01/25/2023] [Indexed: 01/28/2023]
Abstract
Glycinal (HCOCH2 NH2 ) and acetamide (CH3 CONH2 ) are simple molecular building blocks of biomolecules in prebiotic chemistry, though their origin on early Earth and formation in interstellar media remain a mystery. These molecules are formed with their tautomers in low temperature interstellar model ices upon interaction with simulated galactic cosmic rays. Glycinal and acetamide are accessed via barrierless radical-radical reactions of vinoxy (⋅CH2 CHO) and acetyl (⋅C(O)CH3 ), and then undergo keto-enol tautomerization. Exploiting tunable photoionization reflectron time-of-flight mass spectroscopy and photoionization efficiency (PIE) curves, these results demonstrate fundamental reaction pathways for the formation of complex organics through non-equilibrium ice reactions in cold molecular cloud environments. These molecules demonstrate an unconventional starting point for abiotic synthesis of organics relevant to contemporary biomolecules like polypeptides and cell membranes in deep space.
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Affiliation(s)
- Joshua H Marks
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA.,W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Jia Wang
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA.,W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - N Fabian Kleimeier
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA.,W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Andrew M Turner
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA.,W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - André K Eckhardt
- Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, 44801, Bochum, Germany
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA.,W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
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5
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Wang J, Marks JH, Turner AM, Mebel AM, Eckhardt AK, Kaiser RI. Gas-phase detection of oxirene. SCIENCE ADVANCES 2023; 9:eadg1134. [PMID: 36897943 PMCID: PMC10005165 DOI: 10.1126/sciadv.adg1134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 02/08/2023] [Indexed: 06/18/2023]
Abstract
Oxirenes-highly strained 4π Hückel antiaromatic organics-have been recognized as key reactive intermediates in the Wolff rearrangement and in interstellar environments. Predicting short lifetimes and tendency toward ring opening, oxirenes are one of the most mysterious classes of organic transients, with the isolation of oxirene (c-C2H2O) having remained elusive. Here, we report on the preparation of oxirene in low-temperature methanol-acetaldehyde matrices upon energetic processing through isomerization of ketene (H2CCO) followed by resonant energy transfer of the internal energy of oxirene to the vibrational modes (hydroxyl stretching and bending, methyl deformation) of methanol. Oxirene was detected upon sublimation in the gas phase exploiting soft photoionization coupled with a reflectron time-of-flight mass spectrometry. These findings advance our fundamental understanding of the chemical bonding and stability of cyclic, strained molecules and afford a versatile strategy for the synthesis of highly ring-strained transients in extreme environments.
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Affiliation(s)
- Jia Wang
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Joshua H. Marks
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Andrew M. Turner
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Alexander M. Mebel
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
| | - André K. Eckhardt
- Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, Bochum 44801, Germany
| | - Ralf I. Kaiser
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
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6
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Wang J, Marks JH, Turner AM, Nikolayev AA, Azyazov V, Mebel AM, Kaiser RI. Mechanistical study on the formation of hydroxyacetone (CH 3COCH 2OH), methyl acetate (CH 3COOCH 3), and 3-hydroxypropanal (HCOCH 2CH 2OH) along with their enol tautomers (prop-1-ene-1,2-diol (CH 3C(OH)CHOH), prop-2-ene-1,2-diol (CH 2C(OH)CH 2OH), 1-methoxyethen-1-ol (CH 3OC(OH)CH 2) and prop-1-ene-1,3-diol (HOCH 2CHCHOH)) in interstellar ice analogs. Phys Chem Chem Phys 2023; 25:936-953. [PMID: 36285574 DOI: 10.1039/d2cp03543j] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We unravel, for the very first time, the formation pathways of hydroxyacetone (CH3COCH2OH), methyl acetate (CH3COOCH3), and 3-hydroxypropanal (HCOCH2CH2OH), as well as their enol tautomers within mixed ices of methanol (CH3OH) and acetaldehyde (CH3CHO) analogous to interstellar ices in the ISM exposed to ionizing radiation at ultralow temperatures of 5 K. Exploiting photoionization reflectron time-of-flight mass spectrometry (PI-ReToF-MS) and isotopically labeled ices, the reaction products were selectively photoionized allowing for isomer discrimination during the temperature-programmed desorption phase. Based on the distinct mass-to-charge ratios and ionization energies of the identified species, we reveal the formation pathways of hydroxyacetone (CH3COCH2OH), methyl acetate (CH3COOCH3), and 3-hydroxypropanal (HCOCH2CH2OH) via radical-radical recombination reactions and of their enol tautomers (prop-1-ene-1,2-diol (CH3C(OH)CHOH), prop-2-ene-1,2-diol (CH2C(OH)CH2OH), 1-methoxyethen-1-ol (CH3OC(OH)CH2) and prop-1-ene-1,3-diol (HOCH2CHCHOH)) via keto-enol tautomerization. To the best of our knowledge, 1-methoxyethen-1-ol (CH3OC(OH)CH2) and prop-1-ene-1,3-diol (HOCH2CHCHOH) are experimentally identified for the first time. Our findings help to constrain the formation mechanism of hydroxyacetone and methyl acetate detected within star-forming regions and suggest that the hitherto astronomically unobserved isomer 3-hydroxypropanal and its enol tautomers represent promising candidates for future astronomical searches. These enol tautomers may contribute to the molecular synthesis of biologically relevant molecules in deep space due to their nucleophilic character and high reactivity.
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Affiliation(s)
- Jia Wang
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA. .,Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Joshua H Marks
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA. .,Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Andrew M Turner
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA. .,Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Anatoliy A Nikolayev
- Lebedev Physical Institute, Samara 443011, Russia.,Samara National Research University, Samara 443086, Russia
| | | | - Alexander M Mebel
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, USA
| | - Ralf I Kaiser
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA. .,Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
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7
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Bunn H, Raston PL. Characterization of the Coriolis Coupled Far-Infrared Bands of syn-Vinyl Alcohol. J Phys Chem A 2022; 126:2569-2577. [PMID: 35417172 DOI: 10.1021/acs.jpca.2c01379] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rotational emission from vibrationally excited molecules are responsible for a large fraction of lines in the spectra of interstellar molecular clouds. Vinyl alcohol (VA) has two rotamers that differ in energy by 6.4 kJ/mol, both of which have been observed toward the molecular cloud, Sagittarius B2(N) [Turner and Apponi, Astrophys. J. 2001, 561, 207]. Previously, we reported an analysis of the far-infrared spectrum of the higher energy rotamer, anti-VA [Bunn et al. Astrophys. J. 2017, 847, 67], yielding rotational and higher order distortion constants in the first excited vibrational state, and here, we report an analysis of the far-infrared spectrum of the lower energy rotamer, syn-VA, whose spectrum is significantly more complicated on account of Coriolis interactions that result in perturbations to the rovibrational spectrum. We account for those perturbations with the inclusion of Coriolis coupling constants in the fit, which couples the first excited OH torsional (ν15) and CCO bending (ν11) states. Inclusion of them resulted in more physically meaningful rotational and centrifugal distortion constants, and allows for accurate pure rotational line predictions to be made up to high energies. These will be particularly useful in searches for vibrationally excited syn-VA toward warm regions of interstellar molecular clouds, where we predict that it may be significantly abundant.
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Affiliation(s)
- Hayley Bunn
- Department of Chemistry, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Paul L Raston
- Department of Chemistry, University of Adelaide, Adelaide, South Australia 5005, Australia.,Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia 22807, United States
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8
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Kleimeier NF, Kaiser RI. Bottom-Up Synthesis of 1,1-Ethenediol (H 2CC(OH) 2)─The Simplest Unsaturated Geminal Diol─In Interstellar Analogue Ices. J Phys Chem Lett 2022; 13:229-235. [PMID: 34967646 DOI: 10.1021/acs.jpclett.1c03515] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Because of their nucleophilic character and high reactivity, enols─reaction intermediates carrying a hydroxyl group connected to a carbon-carbon double bond─play a key role in the formation of complex organic molecules in astrobiology and biochemistry. Here, we report the first bottom-up preparation of 1,1-ethenediol (H2CC(OH)2)─the simplest unsaturated geminal enol of acetic acid (CH3COOH) and potential precursor for the formation of glycine─in interstellar analogue ices of carbon dioxide and methane processed by proxies of galactic cosmic rays. These enols can easily form via nonequilibrium chemistry in low temperature (10 K) interstellar ices at abundances orders of magnitude higher than thermodynamically predicted. These energetically less favorable tautomers remain stable in ice-coated interstellar nanoparticles in molecular clouds and also upon sublimation into the gas phase in star forming regions thus providing the raw material to a complex and exotic organic chemistry under extreme conditions in deep space.
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Affiliation(s)
- N Fabian Kleimeier
- Department of Chemistry, University of Hawai'i at Ma̅noa, Honolulu, Hawaii 96822, United States
- W. M. Keck Laboratory in Astrochemistry, University of Hawai'i at Ma̅noa, Honolulu, Hawaii 96822, United States
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Ma̅noa, Honolulu, Hawaii 96822, United States
- W. M. Keck Laboratory in Astrochemistry, University of Hawai'i at Ma̅noa, Honolulu, Hawaii 96822, United States
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9
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Zasimov PV, Sanochkina EV, Feldman VI. Radiation-induced transformations of acetaldehyde molecules at cryogenic temperatures: a matrix isolation study. Phys Chem Chem Phys 2021; 24:419-432. [PMID: 34897322 DOI: 10.1039/d1cp03999g] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Acetaldehyde is one of the key small organic molecules involved in astrochemical and atmospheric processes occurring under the action of ionizing and UV radiation. While the UV photochemistry of acetaldehyde is well studied, little is known about the mechanism of processes induced by high-energy radiation. This paper reports the first systematic study on the chemical transformations of CH3CHO molecules resulting from X-ray irradiation under the conditions of matrix isolation in different solid noble gases (Ne, Ar, Kr, and Xe) at 5 K. CO, CH4, H2CCO, H2CCO-H2, C2H2⋯H2O, CH2CHOH, CH3CO˙, CH3˙, HCCO˙, and CCO were identified as the main radiolysis products. The dominant pathway of acetaldehyde degradation involves C-C bond cleavage leading to the formation of carbon monoxide and methane. The second important channel is dehydrogenation resulting in the formation of ketene, a potentially highly reactive species. It was found that the matrix significantly affected both the decomposition efficiency and distribution of the reaction channels. Based on these observations, it was suggested that the formation of the methyl radical as well as vinyl alcohol and the C2H2⋯H2O complex presumably included a significant contribution of ionic pathways. The decomposition of acetyl radicals under photolysis with visible light leading to the CH3˙-CO radical-molecule pair was observed in all matrices, while the recovery of CH3CO˙ in the dark at 5 K was found only in Xe. This finding represents a prominent example of matrix-dependent chemical dynamics (probably, involving tunnelling), which deserves further theoretical studies. Probable mechanisms of acetaldehyde radiolysis and their implications for astrochemistry, atmospheric chemistry and low-temperature chemistry are discussed.
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Affiliation(s)
- Pavel V Zasimov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
| | | | - Vladimir I Feldman
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
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10
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Kleimeier NF, Eckhardt AK, Kaiser RI. Identification of Glycolaldehyde Enol (HOHC═CHOH) in Interstellar Analogue Ices. J Am Chem Soc 2021; 143:14009-14018. [PMID: 34407613 DOI: 10.1021/jacs.1c07978] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Glycolaldehyde is considered the entry point in the aqueous prebiotic formose (Butlerow) reaction although it mainly exists in its unreactive hydrated form in aqueous solution. The characterization of the more reactive nucleophilic enol form under interstellar conditions has remained elusive to date. Here we report on the identification of glycolaldehyde enol (1,2-ethenediol, HOHC═CHOH) in low temperature methanol-bearing ices at temperatures as low as 5 K. Exploiting isotope labeling and isomer-selective photoionization coupled with reflectron time-of-flight mass spectrometry, our results unravel distinct reaction pathways to 1,2-ethenediol, thus demonstrating the kinetic stability, availability for prebiotic sugar formation, and potential detectability in deep space.
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Affiliation(s)
- N Fabian Kleimeier
- Department of Chemistry, University of Hawaii at Ma̅noa, Honolulu, Hawaii 96822, United States.,W. M. Keck Laboratory in Astrochemistry, University of Hawaii at Ma̅noa, Honolulu, Hawaii 96822, United States
| | - André K Eckhardt
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawaii at Ma̅noa, Honolulu, Hawaii 96822, United States.,W. M. Keck Laboratory in Astrochemistry, University of Hawaii at Ma̅noa, Honolulu, Hawaii 96822, United States
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