DIRECT DETECTION OF COMPLEX ORGANIC PRODUCTS IN ULTRAVIOLET (Lyα) AND ELECTRON-IRRADIATED ASTROPHYSICAL AND COMETARY ICE ANALOGS USING TWO-STEP LASER ABLATION AND IONIZATION MASS SPECTROMETRY

Henderson, Bryana L.; Gudipati, Murthy S.

doi:10.1088/0004-637x/800/1/66

Cited by 65 publications

(62 citation statements)

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“…In addition, this work did not use radiation or other energy sources commonly used in such simulations: Sample warming was the only initiator of synthesis. More recent work, using irradiation (UV and electron), has shown in situ synthesis of organic molecules in mixtures starting at 5 K, i.e., the reactions mixtures were not warmed in preparation for analysis (by laser ablation/ionization mass spectrometry) (38).…”

Section: Discussionmentioning

confidence: 99%

Enantiomer excesses of rare and common sugar derivatives in carbonaceous meteorites

Cooper

Rios

2016

Proc. Natl. Acad. Sci. U.S.A.

123

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Biological polymers such as nucleic acids and proteins are constructed of only one-the D or L-of the two possible nonsuperimposable mirror images (enantiomers) of selected organic compounds. However, before the advent of life, it is generally assumed that chemical reactions produced 50:50 (racemic) mixtures of enantiomers, as evidenced by common abiotic laboratory syntheses. Carbonaceous meteorites contain clues to prebiotic chemistry because they preserve a record of some of the Solar System's earliest (∼4.5 Gy) chemical and physical processes. In multiple carbonaceous meteorites, we show that both rare and common sugar monoacids (aldonic acids) contain significant excesses of the D enantiomer, whereas other (comparable) sugar acids and sugar alcohols are racemic. Although the proposed origins of such excesses are still tentative, the findings imply that meteoritic compounds and/or the processes that operated on meteoritic precursors may have played an ancient role in the enantiomer composition of life's carbohydrate-related biopolymers.carbonaceous meteorites | sugar acids | enantiomer excesses | aldonic acids | polyols T he organic phase of carbonaceous meteorites comprises an insoluble "macromolecular" material (1-3), a complex mixture of largely uncharacterized solvent-extractable compounds (4), as well as discrete (identified) soluble organic compounds such as amino acids (3, 5) nucleobases (6, 7), and sugar derivatives (8). Analyses of this prebiotic organic carbon have been important in understanding its early Solar System synthesis and history: Characteristics of the organic phase suggest that it consists of both products and survivors of interstellar/presolar grain irradiation (9) and subsequent encapsulation and aqueous reactions (10, 11) in asteroids "parent bodies."Several identified meteoritic organic compounds are chiral: They can exist as two nonsuperimposable mirror image compounds called enantiomers, commonly designated D and L. To date, most chiral meteoritic compounds are reported to be racemic mixtures, i.e., their D and L enantiomers are equal in abundance (3). Racemic compounds are expected in nature because typical abiotic synthetic processes are (historically) thought to occur in the absence of asymmetric influences. Racemic mixtures are equated with pristine/uncontaminated abiotic samples when discussing meteoritic compounds. However, some meteoritic amino acids that are rare on Earth, i.e., they are not constituents of proteins and therefore less likely to be contaminants, have been confirmed to contain L enantiomer excesses (EE) (3, 12, 13). The origins of such excesses are unknown.Sugars, aldehydes, or ketones that contain multiple carbon hydroxyl (carbon alcohol) groups, are also chiral and were likely necessary for the origin of life. In the majority of extant biological sugars and derivatives ("polyols"), the D enantiomers are significantly more abundant than the L enantiomers (we will note exceptions in Results and Natural Occurrence of Relevant Sugar Derivatives and Enantiomers)...

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Section: Discussionmentioning

confidence: 99%

Enantiomer excesses of rare and common sugar derivatives in carbonaceous meteorites

Cooper

Rios

2016

Proc. Natl. Acad. Sci. U.S.A.

123

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“…Moreover, special care is taken to control the ratio between the used H-atom and UV-photon fluxes in an attempt to get as close as possible to the mean ratios expected for the life-time of dark molecular clouds (Prasad & Tarafdar 1983, Mathis et al 1983, Duley & Williams 1984, Goldsmith & Li 2005, Fuchs et al 2009). It should be noted, though, that the main focus of the present study is on the formation of various N-C bearing molecules and the photochemistry of NO hydrogenation products and not on the photochemistry of CO, H2CO, and CH3OH-ices that leads to the formation of carbon-bearing complex organic molecules (Ӧberg et al 2011, Henderson & Gudipati 2015, Maity et al 2015, Paardekooper et al 2016.…”

Section: H2no/hnoh + H → Nh2oh (4)mentioning

confidence: 97%

Simultaneous hydrogenation and UV-photolysis experiments of NO in CO-rich interstellar ice analogues; linking HNCO, OCN⁻, NH₂CHO, and NH₂OH

Fedoseev

Chuang

Dishoeck

et al. 2016

Mon. Not. R. Astron. Soc.

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The laboratory work presented here, simulates the chemistry on icy dust grains as typical for the "CO freeze-out stage" in dark molecular clouds. It differs from previous studies in that solid-state hydrogenation and vacuum UV-photoprocessing are applied simultaneously to co-depositing molecules. In parallel, the reactions at play are described for fully characterized laboratory conditions. The focus is on the formation of molecules containing both carbon and nitrogen atoms, starting with NO in CO-, H2CO-, and CH3OH-rich ices at 13 K. The experiments yield three important conclusions. 1. Without UV-processing hydroxylamine (NH2OH) is formed, as reported previously. 2. With UV-processing (energetic) NH2 is formed through photodissociation of NH2OH. This radical is key in the formation of species with an N-C bond. 3. The formation of three N-C bearing species, HNCO, OCN -and NH2CHO is observed. The experiments put a clear chemical link between these species; OCN -is found to be a direct derivative of HNCO and the latter is shown to have the same precursor as formamide (NH2CHO). Moreover, the addition of VUV competing channels decreases the amount of NO molecules converted into NH2OHby at least one order of magnitude. Consequently, this decrease in NH2OH formation yield directly influences the amount of NO molecules that can be converted into HNCO, OCN -and NH2CHO.

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“…Other studies have been focusing on the photo-induced reactions taking place in the ice. Extensive studies [039,053,054] show how Ly-alpha irradiation of pure methanol ice results in the formation of larger complex species, including glycolaldehyde and ethylene glycol, and how water ice affects the reaction efficiencies. As P a g e | 10 stated before, methanol is effectively formed upon CO hydrogenation, therefore, methanol is expected to be mixed with CO in the ice in the ISM [016].…”

Section: P a G E |mentioning

confidence: 99%

Atom addition reactions in interstellar ice analogues

Linnartz

Ioppolo

Fedoseev

2015

International Reviews in Physical Chemistry

163

142

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It was in 'The Magellanic Cloud' (1955) -a science fiction novel by Stanislaw Lem -that engineers traveling to another star noticed that their spacecraft for unknown reasons overheated. The cause had to be outside the spaceship, but obviously there was only emptiness, at least compared to terrestrial conditions. The space between the stars, the interstellar medium, however, is not completely empty and at the high speed of the spacecraft the cross-section with impacting particles, even from such a dilute environment, was found to be sufficient to cause an overheating. Today, 60 years later, the interstellar medium has been studied in detail by astronomical observations, reproduced in dedicated laboratory experiments and simulated by complex astrochemical models. The space between the stars is, indeed, far from empty; it comprises gas, dust and ice and the molecules detected so far are both small (diatomics) and large (long carbon chains, PAHs and fullerenes), stable and reactive (radicals, ions, and excited molecules) evidencing an exotic and fascinating chemistry, taking place at low densities, low temperatures and experiencing intense radiation fields.Astrochemists explain the observed chemical complexity in space -so far 185 different molecules (not including isotopologues) have been identified -as the cumulative outcome of P a g e | 2 reactions in the gas phase and on icy dust grains. Gas phase models explain the observed abundances of a substantial part of the observed species, but fail to explain the number densities for stable molecules, as simple as water, methanol or acetonitrile -one of the most promising precursor species for the simplest amino acid glycine -as well as larger compounds such as glycolaldehyde, dimethylether and ethylene glycol. Evidence has been found that these and other complex species, including organic ones, form on icy dust grains that act as catalytic sites for molecule formation. It is here where particles 'accrete, meet, and greet' (i.e., freeze out, diffuse and react) upon energetic and non-energetic processing, such as irradiation by vacuum UV light, interaction with impacting particles (atoms, electrons and cosmic rays) or heating.This review paper summarizes the state-of-the-art in laboratory based interstellar ice chemistry. The focus is on atom addition reactions, illustrating how water, carbon dioxide and methanol can form in the solid state at astronomically relevant temperatures, and also the formation of more complex species such as hydroxylamine, an important prebiotic molecule, and glycolaldehyde, the smallest sugar, is discussed. These reactions are particularly relevant during the 'dark' ages of star and planet formation, i.e., when the role of UV light is restricted.A quantitative characterization of such processes is only possible through dedicated laboratory studies, i.e., under full control of a large set of parameters such as temperature, atom-flux, and ice morphology. The resulting numbers, physical and chemical constants, e.g., barrier heights, react...

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DIRECT DETECTION OF COMPLEX ORGANIC PRODUCTS IN ULTRAVIOLET (Lyα) AND ELECTRON-IRRADIATED ASTROPHYSICAL AND COMETARY ICE ANALOGS USING TWO-STEP LASER ABLATION AND IONIZATION MASS SPECTROMETRY

Cited by 65 publications

References 82 publications

Enantiomer excesses of rare and common sugar derivatives in carbonaceous meteorites

Enantiomer excesses of rare and common sugar derivatives in carbonaceous meteorites

Simultaneous hydrogenation and UV-photolysis experiments of NO in CO-rich interstellar ice analogues; linking HNCO, OCN⁻, NH₂CHO, and NH₂OH

Atom addition reactions in interstellar ice analogues

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DIRECT DETECTION OF COMPLEX ORGANIC PRODUCTS IN ULTRAVIOLET (Lyα) AND ELECTRON-IRRADIATED ASTROPHYSICAL AND COMETARY ICE ANALOGS USING TWO-STEP LASER ABLATION AND IONIZATION MASS SPECTROMETRY

Cited by 65 publications

References 82 publications

Enantiomer excesses of rare and common sugar derivatives in carbonaceous meteorites

Enantiomer excesses of rare and common sugar derivatives in carbonaceous meteorites

Simultaneous hydrogenation and UV-photolysis experiments of NO in CO-rich interstellar ice analogues; linking HNCO, OCN−, NH2CHO, and NH2OH

Atom addition reactions in interstellar ice analogues

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Simultaneous hydrogenation and UV-photolysis experiments of NO in CO-rich interstellar ice analogues; linking HNCO, OCN⁻, NH₂CHO, and NH₂OH