1
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Wagner J, Edel R, Grabnic T, Wiggins B, Sibener SJ. On-surface chemical dynamics of monolayer, bilayer, and many-layered graphene surfaces probed with supersonic beam scattering and STM imaging. Faraday Discuss 2024; 251:435-447. [PMID: 38757539 DOI: 10.1039/d3fd00178d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
We have developed the capability to elucidate interfacial reaction dynamics using an arguably unique combination of supersonic molecular beams combined with in situ STM visualization. These capabilities have been implemented in order to reveal the complex spatiotemporal correlations that govern the oxidation of graphitic systems spanning atomic-, nano-, and meso-length scales. In this study, the 3 nm periodic moiré pattern of monolayer and bilayer graphene on Ru(0001) provides a diverse palette of potential scattering and binding sites at the interface for ground state atomic oxygen. We resolve the site-specificity of atomic oxygen placement on the moiré lattice for both monolayer and bilayer graphene on Ru(0001) with atomic resolution. Angle- and energy-controlled scattering of O(3P) on these interfaces reveals an incisive side-by-side comparison of preferential reactivity of the monolayer surface compared to a more free-standing bilayer graphene ruthenium interface. Morphologically dependent reactivity of many layered graphene (HOPG) and monolayer graphene on Ru(0001) reveal anisotropic on-surface reactivity dependent on the presence of proximal reacted sites or local regions. The kinetics of on-surface oxidation are additionally shown to influence the morphology of surface products by varying the temperature of the interface and flux of reactant species. Such correlations are important in chemisorption, catalysis, materials oxidation and erosion, and film processing-and tunable moiré templated adsorption is a route to well-ordered self-assembled 2D materials for use in next-generation platforms for quantum devices and catalysis. Taken together, these results highlight a new direction in the examination of interfacial reaction dynamics where incident beam kinetic energy and angle of incidence can be used as reaction control parameters, with outcomes such as site-specific reactivity, changes for overall time-evolving mechanisms, and the relative importance of non-adiabatic channels in adsorption all linked to the on-surface fate of chemisorbed species.
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Affiliation(s)
- Joshua Wagner
- The James Franck Institute and Department of Chemistry, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA.
| | - Ross Edel
- The James Franck Institute and Department of Chemistry, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA.
| | - Tim Grabnic
- The James Franck Institute and Department of Chemistry, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA.
| | - Bryan Wiggins
- The James Franck Institute and Department of Chemistry, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA.
| | - Steven J Sibener
- The James Franck Institute and Department of Chemistry, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA.
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2
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Nixon CA. The Composition and Chemistry of Titan's Atmosphere. ACS EARTH & SPACE CHEMISTRY 2024; 8:406-456. [PMID: 38533193 PMCID: PMC10961852 DOI: 10.1021/acsearthspacechem.2c00041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 11/02/2023] [Accepted: 02/02/2024] [Indexed: 03/28/2024]
Abstract
In this review I summarize the current state of knowledge about the composition of Titan's atmosphere and our current understanding of the suggested chemistry that leads to that observed composition. I begin with our present knowledge of the atmospheric composition, garnered from a variety of measurements including Cassini-Huygens, the Atacama Large Millimeter/submillimeter Array, and other ground- and space-based telescopes. This review focuses on the typical vertical profiles of gases at low latitudes rather than global and temporal variations. The main body of the review presents a chemical description of how complex molecules are believed to arise from simpler species, considering all known "stable" molecules-those that have been uniquely identified in the neutral atmosphere. The last section of the review is devoted to the gaps in our present knowledge of Titan's chemical composition and how further work may fill those gaps.
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Affiliation(s)
- Conor A. Nixon
- Planetary Systems Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, Maryland 20771, United
States
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3
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Marks J, Wang J, Sun BJ, McAnally M, Turner AM, Chang AHH, Kaiser RI. Thermal Synthesis of Carbamic Acid and Its Dimer in Interstellar Ices: A Reservoir of Interstellar Amino Acids. ACS CENTRAL SCIENCE 2023; 9:2241-2250. [PMID: 38161363 PMCID: PMC10755733 DOI: 10.1021/acscentsci.3c01108] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 10/13/2023] [Accepted: 10/19/2023] [Indexed: 01/03/2024]
Abstract
Reactions in interstellar ices are shown to be capable of producing key prebiotic molecules without energetic radiation that are necessary for the origins of life. When present in interstellar ices, carbamic acid (H2NCOOH) can serve as a condensed-phase source of the molecular building blocks for more complex proteinogenic amino acids. Here, Fourier transform infrared spectroscopy during heating of analogue interstellar ices composed of carbon dioxide and ammonia identifies the lower limit for thermal synthesis to be 62 ± 3 K for carbamic acid and 39 ± 4 K for its salt ammonium carbamate ([H2NCOO-][NH4+]). While solvation increases the rates of formation and decomposition of carbamic acid in ice, the absence of solvent effects after sublimation results in a significant barrier to dissociation and a stable gas-phase molecule. Photoionization reflectron time-of-flight mass spectrometry permits an unprecedented degree of sensitivity toward gaseous carbamic acid and demonstrates sublimation of carbamic acid from decomposition of ammonium carbamate and again at higher temperatures from carbamic acid dimers. Since the dimer is observed at temperatures up to 290 K, similar to the environment of a protoplanetary disk, this dimer is a promising reservoir of amino acids during the formation of stars and planets.
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Affiliation(s)
- Joshua
H. Marks
- W.
M. Keck Research Laboratory in Astrochemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United States
- Department
of Chemistry, University of Hawai’i
at Manoa, Honolulu, Hawaii 96822, United States
| | - Jia Wang
- W.
M. Keck Research Laboratory in Astrochemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United States
- Department
of Chemistry, University of Hawai’i
at Manoa, Honolulu, Hawaii 96822, United States
| | - Bing-Jian Sun
- Department
of Chemistry, National Dong Hwa University, Hualien 974, Taiwan
| | - Mason McAnally
- W.
M. Keck Research Laboratory in Astrochemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United States
- Department
of Chemistry, University of Hawai’i
at Manoa, Honolulu, Hawaii 96822, United States
| | - Andrew M. Turner
- W.
M. Keck Research Laboratory in Astrochemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United States
- Department
of Chemistry, University of Hawai’i
at Manoa, Honolulu, Hawaii 96822, United States
| | - Agnes H.-H. Chang
- Department
of Chemistry, National Dong Hwa University, Hualien 974, Taiwan
| | - Ralf I. Kaiser
- W.
M. Keck Research Laboratory in Astrochemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United States
- Department
of Chemistry, University of Hawai’i
at Manoa, Honolulu, Hawaii 96822, United States
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4
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Brann M, Hansknecht SP, Ma X, Sibener SJ. Differential Condensation of Methane Isotopologues Leading to Isotopic Enrichment under Non-equilibrium Gas-Surface Collision Conditions. J Phys Chem A 2021; 125:9405-9413. [PMID: 34658236 PMCID: PMC8558857 DOI: 10.1021/acs.jpca.1c07826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 10/05/2021] [Indexed: 11/30/2022]
Abstract
We examine the initial differential sticking probability of CH4 and CD4 on CH4 and CD4 ices under nonequilibrium flow conditions using a combination of experimental methods and numerical simulations. The experimental methods include time-resolved in situ reflection-absorption infrared spectroscopy (RAIRS) for monitoring on-surface gaseous condensation and complementary King and Wells mass spectrometry techniques for monitoring sticking probabilities that provide confirmatory results via a second independent measurement method. Seeded supersonic beams are employed so that the entrained CH4 and CD4 have the same incident velocity but different kinetic energies and momenta. We found that as the incident velocity of CH4 and CD4 increases, the sticking probabilities for both molecules on a CH4 condensed film decrease systematically, but that preferential sticking and condensation occur for CD4. These observations differ when condensed CD4 is used as the target interface, indicating that the film's phonon and rovibrational densities of states, and collisional energy transfer cross sections, have a role in differential energy accommodation between isotopically substituted incident species. Lastly, we employed a mixed incident supersonic beam composed of both CH4 and CD4 in a 3:1 ratio and measured the condensate composition as well as the sticking probability. When doing so, we see the same effect in the condensed mixed film, supporting an isotopic enrichment of the heavier isotope. We propose that enhanced multi-phonon interactions and inelastic cross sections between the incident CD4 projectile and the CH4 film allow for more efficacious gas-surface energy transfer. VENUS code MD simulations show the same sticking probability differences between isotopologues as observed in the gas-surface scattering experiments. Ongoing analyses of these trajectories will provide additional insights into energy and momentum transfer between the incident species and the interface. These results offer a new route for isotope enrichment via preferential condensation of heavier isotopes and isotopologues during gas-surface collisions under specifically selected substrate, gas-mixture, and incident velocity conditions. They also yield valuable insights into gaseous condensation under non-equilibrium conditions such as occur in aircraft flight in low-temperature environments. Moreover, these results can help to explain the increased abundance of deuterium in solar system planets and can be incorporated into astrophysical models of interstellar icy dust grain surface processes.
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Affiliation(s)
- Michelle
R. Brann
- The James Franck Institute
and Department of Chemistry, The University
of Chicago, 929 E. 57th Street, Chicago, Illinois 60637, United
States
| | - Stephen P. Hansknecht
- The James Franck Institute
and Department of Chemistry, The University
of Chicago, 929 E. 57th Street, Chicago, Illinois 60637, United
States
| | - Xinyou Ma
- The James Franck Institute
and Department of Chemistry, The University
of Chicago, 929 E. 57th Street, Chicago, Illinois 60637, United
States
| | - S. J. Sibener
- The James Franck Institute
and Department of Chemistry, The University
of Chicago, 929 E. 57th Street, Chicago, Illinois 60637, United
States
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5
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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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6
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Bocková J, Rebelo A, Ryszka M, Pandey R, Mészáros D, Limão-Vieira P, Papp P, Mason NJ, Townsend D, Nixon KL, Vizcaino V, Poully JC, Eden S. Thermal desorption effects on fragment ion production from multi-photon ionized uridine and selected analogues. RSC Adv 2021; 11:20612-20621. [PMID: 35479354 PMCID: PMC9033967 DOI: 10.1039/d1ra01873f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 05/09/2021] [Indexed: 12/22/2022] Open
Abstract
Experiments on neutral gas-phase nucleosides are often complicated by thermal lability. Previous mass spectrometry studies of nucleosides have identified enhanced relative production of nucleobase ions (e.g. uracil+ from uridine) as a function of desorption temperature to be the critical indicator of thermal decomposition. On this basis, the present multi-photon ionization (MPI) experiments demonstrate that laser-based thermal desorption is effective for producing uridine, 5-methyluridine, and 2′-deoxyuridine targets without thermal decomposition. Our experiments also revealed one notable thermal dependence: the relative production of the sugar ion C5H9O4+ from intact uridine increased substantially with the desorption laser power and this only occurred at MPI wavelengths below 250 nm (full range studied 222–265 nm). We argue that this effect can only be rationalized plausibly in terms of changing populations of different isomers, tautomers, or conformers in the target as a function of the thermal desorption conditions. Furthermore, the wavelength threshold behavior of this thermally-sensitive MPI channel indicates a critical dependence on neutral excited state dynamics between the absorption of the first and second photons. The experimental results are complemented by density functional theory (DFT) optimizations of the lowest-energy structure of uridine and two further conformers distinguished by different orientations of the hydroxymethyl group on the sugar part of the molecule. The energies of the transitions states between these three conformers are low compared with the energy required for decomposition. This work reveals the first experimental evidence supporting isomer-dependence in the radiation response of a nucleoside.![]()
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Affiliation(s)
- J Bocková
- School of Physical Sciences, The Open University Walton Hall Milton Keynes MK7 6AA UK
| | - A Rebelo
- School of Physical Sciences, The Open University Walton Hall Milton Keynes MK7 6AA UK .,Atomic and Molecular Collisions Laboratory, CEFITEC, Department of Physics, FCT - Universidade NOVA de Lisboa P-2829-516 Caparica Portugal
| | - M Ryszka
- School of Physical Sciences, The Open University Walton Hall Milton Keynes MK7 6AA UK
| | - R Pandey
- School of Physical Sciences, The Open University Walton Hall Milton Keynes MK7 6AA UK
| | - D Mészáros
- Department of Experimental Physics, Comenius University in Bratislava Mlynská dolina F2 84248 Bratislava Slovakia
| | - P Limão-Vieira
- Atomic and Molecular Collisions Laboratory, CEFITEC, Department of Physics, FCT - Universidade NOVA de Lisboa P-2829-516 Caparica Portugal
| | - P Papp
- Department of Experimental Physics, Comenius University in Bratislava Mlynská dolina F2 84248 Bratislava Slovakia
| | - N J Mason
- School of Physical Sciences, The Open University Walton Hall Milton Keynes MK7 6AA UK .,School of Physical Sciences, Ingram Building, University of Kent Canterbury CT2 7NH UK
| | - D Townsend
- Institute of Photonics and Quantum Sciences, Heriot-Watt University Edinburgh EH14 4AS UK.,Institute of Chemical Sciences, Heriot-Watt University Edinburgh EH14 4AS UK
| | - K L Nixon
- School of Life, Health, and Chemical Sciences, The Open University Walton Hall Milton Keynes MK7 6AA UK.,School of Sciences, University of Wolverhampton Wulfruna Street Wolverhampton WV1 1LY UK
| | - V Vizcaino
- CIMAP UMR 6252, CEA/CNRS/ENSICAEN/Université de Caen Normandie, GANIL Bd Becquerel BP 5133 14070 Caen France
| | - J-C Poully
- CIMAP UMR 6252, CEA/CNRS/ENSICAEN/Université de Caen Normandie, GANIL Bd Becquerel BP 5133 14070 Caen France
| | - S Eden
- School of Physical Sciences, The Open University Walton Hall Milton Keynes MK7 6AA UK
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7
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Turner AM, Chandra S, Fortenberry RC, Kaiser RI. A Photoionization Reflectron Time-of-Flight Mass Spectrometric Study on the Detection of Ethynamine (HCCNH 2 ) and 2H-Azirine (c-H 2 CCHN). Chemphyschem 2021; 22:985-994. [PMID: 33797172 DOI: 10.1002/cphc.202100064] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/23/2021] [Indexed: 11/07/2022]
Abstract
Ices of acetylene (C2 H2 ) and ammonia (NH3 ) were irradiated with energetic electrons to simulate interstellar ices processed by galactic cosmic rays in order to investigate the formation of C2 H3 N isomers. Supported by quantum chemical calculations, experiments detected product molecules as they sublime from the ices using photoionization reflectron time-of-flight mass spectrometry (PI-ReTOF-MS). Isotopically-labeled ices confirmed the C2 H3 N assignments while photon energies of 8.81 eV, 9.80 eV, and 10.49 eV were utilized to discriminate isomers based on their known ionization energies. Results indicate the formation of ethynamine (HCCNH2 ) and 2H-azirine (c-H2 CCHN) in the irradiated C2 H2 :NH3 ices, and the energetics of their formation mechanisms are discussed. These findings suggest that these two isomers can form in interstellar ices and, upon sublimation during the hot core phase, could be detected using radio astronomy.
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Affiliation(s)
- Andrew M Turner
- Department of Chemistry, University of Hawaii at Manoa, 2545 McCarthy Mall, Honolulu, HI 96822, USA.,W. M. Keck Laboratory in Astrochemistry, University of Hawaii at Manoa, 2545 McCarthy Mall, Honolulu, HI 96822, USA
| | - Sankhabrata Chandra
- Department of Chemistry, University of Hawaii at Manoa, 2545 McCarthy Mall, Honolulu, HI 96822, USA.,W. M. Keck Laboratory in Astrochemistry, University of Hawaii at Manoa, 2545 McCarthy Mall, Honolulu, HI 96822, USA
| | - Ryan C Fortenberry
- Department of Chemistry & Biochemistry, University of Mississippi, Mississippi, 38677-1848, USA
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawaii at Manoa, 2545 McCarthy Mall, Honolulu, HI 96822, USA.,W. M. Keck Laboratory in Astrochemistry, University of Hawaii at Manoa, 2545 McCarthy Mall, Honolulu, HI 96822, USA
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8
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Turner AM, Kaiser RI. Exploiting Photoionization Reflectron Time-of-Flight Mass Spectrometry to Explore Molecular Mass Growth Processes to Complex Organic Molecules in Interstellar and Solar System Ice Analogs. Acc Chem Res 2020; 53:2791-2805. [PMID: 33258604 DOI: 10.1021/acs.accounts.0c00584] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
ConspectusThis Account presents recent advances in our understanding on the formation pathways of complex organic molecules (COMs) within interstellar analog ices on ice-coated interstellar nanoparticles upon interaction with ionizing radiation exploiting reflectron time-of-flight mass spectrometry (ReTOF-MS) coupled with tunable vacuum ultraviolet (VUV) single photon ionization (PI) and resonance enhanced multiphoton ionization (REMPI) of the subliming molecules during the temperature-programmed desorption (TPD) phase. Laboratory simulation experiments provided compelling evidence that key classes of complex organics (aromatic hydrocarbons, alcohols, ethers, aldehydes, enols, ketones, and carboxylic acids) can be synthesized upon exposure of astrophysically relevant model ices to ionizing radiation within and throughout the ices at temperatures as low as 5 K.Molecular mass growth processes can be initiated by suprathermal or electronically excited reactants along with barrierless radical-radical recombination if both radicals hold a proper recombination geometry. Methyl (CH3), amino (NH2), hydroxyl (OH), ethyl (C2H5), vinyl (C2H3), ethynyl (C2H), formyl (HCO), hydroxycarbonyl (HOCO), hydroxymethyl (CH2OH), methoxy (CH3O), and acetyl (CH3CO) represent readily available reactants for radical-radical recombination within the ices. Reactive singlet species were found to insert without barrier into carbon-hydrogen and carbon-carbon single bonds (carbene) leading to an extension of the carbon chain and may add to carbon-carbon double bonds (carbene, atomic oxygen) forming cyclic reaction products. These galactic cosmic ray-triggered nonequilibrium pathways overcome previous obstacles of hypothesized thermal grain-surface processes and operate throughout the ice at 5 K. Our investigations discriminate between multiple structural isomers such as alcohols/ethers, aldehydes/enols, and cyclic/acyclic carbonyls. These data provide quantitative, isomer selective input parameters for a cosmic ray-dictated formation of complex organics in interstellar ices and are fully able to replicate the astronomical observations of complex organics over typical lifetimes of molecular clouds of a few 106 to 107 years. Overall, PI-ReTOF-MS revealed that the processing of astrophysically relevant ices can lead to multifaceted mixtures of organics reaching molecular weights of up to 200 amu. Further advances in laboratory techniques beyond the FTIR-QMS limit are clearly desired not only to confidently assign detection in laboratory ice analog experiments of increasingly more complex molecules of interest but also from the viewpoint of future astronomical searches in the age of the Atacama Large Millimeter/submillimeter Array (ALMA).
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Affiliation(s)
- Andrew M. Turner
- Department of Chemistry and W.M. Keck Research Laboratory in Astrochemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United States
| | - Ralf I. Kaiser
- Department of Chemistry and W.M. Keck Research Laboratory in Astrochemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United States
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9
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Singh SK, Vuppuluri V, Son SF, Kaiser RI. Investigating the Photochemical Decomposition of Solid 1,3,5-Trinitro-1,3,5-triazinane (RDX). J Phys Chem A 2020; 124:6801-6823. [DOI: 10.1021/acs.jpca.0c05726] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Santosh K. Singh
- Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, United States
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii, Honolulu, Hawaii 96822, United States
| | - Vasant Vuppuluri
- Mechanical Engineering, Purdue Energetics Research Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Steven F. Son
- Mechanical Engineering, Purdue Energetics Research Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Ralf I. Kaiser
- Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, United States
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii, Honolulu, Hawaii 96822, United States
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10
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Kleimeier NF, Turner AM, Fortenberry RC, Kaiser RI. On the Formation of the Popcorn Flavorant 2,3-Butanedione (CH 3 COCOCH 3 ) in Acetaldehyde-Containing Interstellar Ices. Chemphyschem 2020; 21:1531-1540. [PMID: 32458552 DOI: 10.1002/cphc.202000116] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/25/2020] [Indexed: 11/06/2022]
Abstract
Acetaldehyde (CH3 CHO) is ubiquitous throughout the interstellar medium and has been observed in cold molecular clouds, star forming regions, and in meteorites such as Murchison. As the simplest methyl-bearing aldehyde, acetaldehyde constitutes a critical precursor to prebiotic molecules such as the sugar deoxyribose and amino acids via the Strecker synthesis. In this study, we reveal the first laboratory detection of 2,3-butanedione (diacetyl, CH3 COCOCH3 ) - a butter and popcorn flavorant - synthesized within acetaldehyde-based interstellar analog ices exposed to ionizing radiation at 5 K. Detailed isotopic substitution experiments combined with tunable vacuum ultraviolet (VUV) photoionization of the subliming molecules demonstrate that 2,3-butanedione is formed predominantly via the barrier-less radical-radical reaction of two acetyl radicals (CH3 ĊO). These processes are of fundamental importance for a detailed understanding of how complex organic molecules (COMs) are synthesized in deep space thus constraining the molecular structures and complexity of molecules forming in extraterrestrial ices containing acetaldehyde through a vigorous galactic cosmic ray driven non-equilibrium chemistry.
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Affiliation(s)
- N Fabian Kleimeier
- Department of Chemistry and W. M. Keck Research Laboratory in Astrochemistry, University of Hawai'i at Manoa 2545 McCarthy Mall, Honolulu, HI, 96822, USA
| | - Andrew M Turner
- Department of Chemistry and W. M. Keck Research Laboratory in Astrochemistry, University of Hawai'i at Manoa 2545 McCarthy Mall, Honolulu, HI, 96822, USA
| | - Ryan C Fortenberry
- Department of Chemistry & Biochemistry, University of Mississippi, 322 Coulter Hall, University, MS, 38677-1848, USA
| | - Ralf I Kaiser
- Department of Chemistry and W. M. Keck Research Laboratory in Astrochemistry, University of Hawai'i at Manoa 2545 McCarthy Mall, Honolulu, HI, 96822, USA
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11
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Singh SK, Tsai TY, Sun BJ, Chang AHH, Mebel AM, Kaiser RI. Gas Phase Identification of the Elusive N-Hydroxyoxaziridine (c-H 2CON(OH)): A Chiral Molecule. J Phys Chem Lett 2020; 11:5383-5389. [PMID: 32527090 DOI: 10.1021/acs.jpclett.0c01277] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The hitherto elusive N-hydroxyoxaziridine molecule (c-H2CON(OH)), a chiral, high energy isomer of nitromethane (CH3NO2) and one of the simplest representatives of an oxaziridine, is detected in the gas phase. Electronic structure calculations propose an impending synthesis eventually via addition of carbene (CH2) to the nitrogen-oxygen double bond of nitrous acid (HONO). The oxaziridine ring demonstrates an unusual kinetic stability toward ring opening compared to the isoeletronic cyclopropane (C3H6) counterpart. This system defines a fundamental benchmark to explore the formation and stability of racemic derivatives of strained oxaziridines (c-H2CONH) and changes our perception how we think about fundamental decomposition and isomerization mechanisms in (model compounds of) energetic materials.
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Affiliation(s)
- Santosh K Singh
- Department of Chemistry, University of Hawaii, 2545 McCarthy Mall, Honolulu, Hawaii 96822, United States
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii, Honolulu, Hawaii 96822, United States
| | - Tang-Yu Tsai
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan
| | - Bing-Jian Sun
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan
| | - Agnes H H Chang
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan
| | - Alexander M Mebel
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawaii, 2545 McCarthy Mall, Honolulu, Hawaii 96822, United States
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii, Honolulu, Hawaii 96822, United States
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12
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Singh SK, La Jeunesse J, Zhu C, Kleimeier NF, Chen KH, Sun BJ, Chang AHH, Kaiser RI. Gas phase identification of the elusive oxaziridine (cyclo-H2CONH) – an optically active molecule. Chem Commun (Camb) 2020; 56:15643-15646. [DOI: 10.1039/d0cc06760a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
First detection of the chiral oxaziridine (cyclo-H2CONH) molecule.
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Affiliation(s)
- Santosh K. Singh
- Department of Chemistry
- University of Hawaii
- Honolulu
- USA
- W. M. Keck Research Laboratory in Astrochemistry
| | - Jesse La Jeunesse
- Department of Chemistry
- University of Hawaii
- Honolulu
- USA
- W. M. Keck Research Laboratory in Astrochemistry
| | - Cheng Zhu
- Department of Chemistry
- University of Hawaii
- Honolulu
- USA
- W. M. Keck Research Laboratory in Astrochemistry
| | - N. Fabian Kleimeier
- Department of Chemistry
- University of Hawaii
- Honolulu
- USA
- W. M. Keck Research Laboratory in Astrochemistry
| | - Kuo-Hsin Chen
- Department of Chemistry
- National Dong Hwa University
- Shoufeng
- Taiwan
| | - Bing-Jian Sun
- Department of Chemistry
- National Dong Hwa University
- Shoufeng
- Taiwan
| | | | - Ralf I. Kaiser
- Department of Chemistry
- University of Hawaii
- Honolulu
- USA
- W. M. Keck Research Laboratory in Astrochemistry
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13
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Abplanalp MJ, Frigge R, Kaiser RI. Low-temperature synthesis of polycyclic aromatic hydrocarbons in Titan's surface ices and on airless bodies. SCIENCE ADVANCES 2019; 5:eaaw5841. [PMID: 31663015 PMCID: PMC6795510 DOI: 10.1126/sciadv.aaw5841] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 09/22/2019] [Indexed: 06/10/2023]
Abstract
Titan's equatorial dunes represent the most monumental surface structures in our Solar System, but the chemical composition of their dark organics remains a fundamental, unsolved enigma, with solid acetylene detected near the dunes implicated as a key feedstock. Here, we reveal in laboratory simulation experiments that aromatics such as benzene, naphthalene, and phenanthrene-prospective building blocks of the organic dune material-can be efficiently synthesized via galactic cosmic ray exposure of low-temperature acetylene ices on Titan's surface, hence challenging conventional wisdom that aromatic hydrocarbons are formed solely in Titan's atmosphere. These processes are also of critical importance in unraveling the origin and chemical composition of the dark surfaces of airless bodies in the outer Solar System, where hydrocarbon precipitation from the atmosphere cannot occur. This finding notably advances our understanding of the distribution of carbon throughout our Solar System such as on Kuiper belt objects like Makemake.
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Affiliation(s)
- Matthew J. Abplanalp
- 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
| | - Robert Frigge
- 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
| | - 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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14
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Yocum KM, Smith HH, Todd EW, Mora L, Gerakines PA, Milam SN, Widicus Weaver SL. Millimeter/Submillimeter Spectroscopic Detection of Desorbed Ices: A New Technique in Laboratory Astrochemistry. J Phys Chem A 2019; 123:8702-8708. [PMID: 31556610 DOI: 10.1021/acs.jpca.9b04587] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
A new laboratory technique has been developed that utilizes gas-phase, direct-absorption millimeter and submillimeter spectroscopy to detect and identify desorbed species from interstellar and cometary ice analogues. Rotational spectroscopy is a powerful structure-specific technique for detecting isomers and other species possessing the same mass that are indistinguishable with mass spectrometry. Furthermore, the resultant laboratory spectra are directly comparable to observational data from far-infrared and millimeter telescopes. Here, we present the proof-of-concept measurements of the detection of thermally desorbed H2O, D2O, and CH3OH originating in a solid film created at low temperature (∼12 K). The surface binding energy of H2O is reported and compared to results from traditional techniques, including mass spectrometry and quartz-crystal microbalance measurements of mass loss. Lastly, we demonstrate that this technique can be used to derive thermodynamic values including the sublimation enthalpy and entropy of H2O.
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Affiliation(s)
- Katarina M Yocum
- Department of Chemistry , Emory University , Atlanta 30322 , Georgia , United States
| | - Houston H Smith
- Department of Chemistry , Emory University , Atlanta 30322 , Georgia , United States
| | - Ethan W Todd
- Department of Chemistry , Emory University , Atlanta 30322 , Georgia , United States
| | - Leslie Mora
- Department of Chemistry , Emory University , Atlanta 30322 , Georgia , United States
| | - Perry A Gerakines
- Astrochemistry Laboratory , NASA Goddard Space Flight Center , Greenbelt 20771 , Maryland , United States
| | - Stefanie N Milam
- Astrochemistry Laboratory , NASA Goddard Space Flight Center , Greenbelt 20771 , Maryland , United States
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15
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Abplanalp MJ, Kaiser RI. On the formation of complex organic molecules in the interstellar medium: untangling the chemical complexity of carbon monoxide-hydrocarbon containing ice analogues exposed to ionizing radiation via a combined infrared and reflectron time-of-flight analysis. Phys Chem Chem Phys 2019; 21:16949-16980. [PMID: 31339133 DOI: 10.1039/c9cp01793c] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recently, over 200 molecules have been detected in the interstellar medium (ISM), with about one third being complex organic molecules (COMs), molecules containing six or more atoms. Over the last few decades, astrophysical laboratory experiments have shown that several COMs are formed via interaction of ionizing radiation within ices deposited on interstellar dust particles at 10 K (H2O, CH3OH, CO, CO2, CH4, NH3). However, there is still a lack of understanding of the chemical complexity that is available through individual ice constituents. The present research investigates experimentally the synthesis of carbon, hydrogen, and oxygen bearing COMs from interstellar ice analogues containing carbon monoxide (CO) and methane (CH4), ethane (C2H6), ethylene (C2H4), or acetylene (C2H2) exposed to ionizing radiation. Utilizing online and in situ techniques, such as infrared spectroscopy and tunable photoionization reflectron time-of-flight mass spectrometry (PI-ReTOF-MS), specific isomers produced could be characterized. A total of 12 chemically different groups were detected corresponding to C2HnO (n = 2, 4, 6), C3HnO (n = 2, 4, 6, 8), C4HnO (n = 4, 6, 8, 10), C5HnO (n = 4, 6, 8, 10), C6HnO (n = 4, 6, 8, 10, 12, 14), C2HnO2 (n = 2, 4), C3HnO2 (n = 4, 6, 8), C4HnO2 (n = 4, 6, 8, 10), C5HnO2 (n = 6, 8), C6HnO2 (n = 8, 10, 12), C4HnO3 (n = 4, 6, 8), and C5HnO3 (n = 6, 8). More than half of these isomer specifically identified molecules have been identified in the ISM, and the remaining COMs detected here can be utilized to guide future astronomical observations. Of these isomers, three groups - alcohols, aldehydes, and molecules containing two of these functional groups - displayed varying degrees of unsaturation. Also, the detection of 1-propanol, 2-propanol, 1-butanal, and 2-methyl-propanal has significant implications as the propyl and isopropyl moieties (C3H7), which have already been detected in the ISM via propyl cyanide and isopropyl cyanide, could be detected in our laboratory studies. General reaction mechanisms for their formation are also proposed, with distinct follow-up studies being imperative to elucidate the complexity of COMs synthesized in these ices.
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Affiliation(s)
- Matthew J Abplanalp
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA. and Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Ralf I Kaiser
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA. and Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
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16
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Thomas AM, He C, Zhao L, Galimova GR, Mebel AM, Kaiser RI. Combined Experimental and Computational Study on the Reaction Dynamics of the 1-Propynyl (CH 3CC)-1,3-Butadiene (CH 2CHCHCH 2) System and the Formation of Toluene under Single Collision Conditions. J Phys Chem A 2019; 123:4104-4118. [PMID: 31017790 DOI: 10.1021/acs.jpca.9b00092] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The crossed beams reactions of the 1-propynyl radical (CH3CC; X2A1) with 1,3-butadiene (CH2CHCHCH2; X1Ag), 1,3-butadiene- d6 (CD2CDCDCD2; X1Ag), 1,3-butadiene- d4 (CD2CHCHCD2; X1Ag), and 1,3-butadiene- d2 (CH2CDCDCH2; X1Ag) were performed under single collision conditions at collision energies of about 40 kJ mol-1. The underlying reaction mechanisms were unraveled through the combination of the experimental data with electronic structure calculations at the CCSD(T)-F12/cc-pVTZ-f12//B3LYP/6-311G(d,p) + ZPE(B3LYP/6-311G(d,p) level of theory along with statistical Rice-Ramsperger-Kassel-Marcus (RRKM) calculations. Together, these data suggest the formation of the thermodynamically most stable C7H8 isomer-toluene (C6H5CH3)-via the barrierless addition of 1-propynyl to the 1,3-butadiene terminal carbon atom, forming a low-lying C7H9 intermediate that undergoes multiple isomerization steps resulting in cyclization and ultimately aromatization following hydrogen atom elimination. RRKM calculations predict that the thermodynamically less stable isomers 1,3-heptadien-5-yne, 5-methylene-1,3-cyclohexadiene, and 3-methylene-1-hexen-4-yne are also synthesized. Since the 1-propynyl radical may be present in cold molecular clouds such as TMC-1, this pathway could potentially serve as a carrier of the methyl group incorporating itself into methyl-substituted (poly)acetylenes or aromatic systems such as toluene via overall exoergic reaction mechanisms that are uninhibited by an entrance barrier. Such pathways are a necessary alternative to existing high energy reactions leading to toluene that are formally closed in the cold regions of space and are an important step toward understanding the synthesis of polycyclic aromatic hydrocarbons (PAHs) in space's harsh extremes.
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Affiliation(s)
- Aaron M Thomas
- Department of Chemistry , University of Hawai'i at Manoa , Honolulu , Hawaii 96822 , United States
| | - Chao He
- Department of Chemistry , University of Hawai'i at Manoa , Honolulu , Hawaii 96822 , United States
| | - Long Zhao
- Department of Chemistry , University of Hawai'i at Manoa , Honolulu , Hawaii 96822 , United States
| | - Galiya R Galimova
- Department of Chemistry and Biochemistry , Florida International University , Miami , Florida 33199 , United States.,Samara National Research University , Samara 443086 , Russia
| | - Alexander M Mebel
- Department of Chemistry and Biochemistry , Florida International University , Miami , Florida 33199 , United States
| | - Ralf I Kaiser
- Department of Chemistry , University of Hawai'i at Manoa , Honolulu , Hawaii 96822 , United States
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