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Vaneeva EE, Lepeshkin SV, Oganov AR. Prediction and Rationalization of Abundant C-N-H Molecules in Different Environments. J Phys Chem Lett 2023; 14:8367-8375. [PMID: 37705151 DOI: 10.1021/acs.jpclett.3c01753] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
The extreme chemical diversity of CmNnHk molecules is at the same time very important (central in organic chemistry) and difficult to rationalize in the sense that some molecules are abundant and easy to synthesize, while others are rare and difficult to make. Using the recently developed criteria of molecular "magicity", combined with evolutionary structure prediction and quantum-chemical calculations, we study these molecules in a wide range of compositions (0 ≤ m ≤ 13, 0 ≤ n ≤ 4, and 0 ≤ k ≤ 14). "Magic" molecules are defined as those that are lower in energy than any isochemical mixture of molecules with the nearest compositions. The predicted "magic" molecules are in good agreement with compounds found in versatile environments (interstellar and circumstellar media, Titan's lower atmosphere, and crude oil fractions) and in experimental chemistry. This work shows the predictive power of our approach, capable of predicting and explaining stable molecules in complex systems.
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Affiliation(s)
- Elizaveta E Vaneeva
- Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, bld. 1, 121205 Moscow, Russian Federation
| | - Sergey V Lepeshkin
- Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, bld. 1, 121205 Moscow, Russian Federation
- Lebedev Physical Institute, Russian Academy of Sciences, Leninsky Ave. 53, 119991 Moscow, Russian Federation
- Vernadsky Institute of Geochemistry and Analytical Chemistry Russian Academy of Sciences, Kosygin St. 19, 119991 Moscow, Russian Federation
| | - Artem R Oganov
- Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, bld. 1, 121205 Moscow, Russian Federation
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2
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Paul D, Sun BJ, He C, Yang Z, Goettl SJ, Yang T, Zhang BY, Chang AHH, Kaiser RI. Competing Si 2CH 4-H 2 and SiCH 2-SiH 4 Channels in the Bimolecular Reaction of Ground-State Atomic Carbon (C( 3P j)) with Disilane (Si 2H 6, X 1A 1g) under Single Collision Conditions. J Phys Chem A 2023; 127:1901-1908. [PMID: 36790335 DOI: 10.1021/acs.jpca.2c08417] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
The bimolecular gas-phase reaction of ground-state atomic carbon (C(3Pj)) with disilane (Si2H6, X1A1g) was explored under single-collision conditions in a crossed molecular beam machine at a collision energy of 36.6 ± 4.5 kJ mol-1. Two channels were observed: a molecular hydrogen elimination plus Si2CH4 (reaction 1) pathway and a silane loss channel along with the formation of SiCH2 (reaction 2), with branching ratios of 20 ± 3 and 80 ± 4%, respectively. Both channels involved indirect scattering dynamics via long-lived Si2CH6 reaction intermediate(s); the latter eject molecular hydrogen and silane in "molecular" elimination channels within the rotational plane of the fragmenting intermediate nearly perpendicularly to the total angular momentum vector. These molecular elimination channels are associated with tight exit transition states as reflected in a significant electron rearrangement as visible from the chemical bonding in the light reaction products molecular hydrogen and silane. Once these hydrogenated silicon-carbide clusters are formed within the inner envelope of carbon stars such as of IRC + 10216, the stellar wind can drive both Si2CH4 and SiCH2 to the outside sections of the envelope, where they can be photolyzed. This is of particular importance to unravel potential formation pathways to disilicon monocarbide (Si2C) observed recently in the circumstellar shell of IRC + 10216.
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Affiliation(s)
- Dababrata Paul
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Bing-Jian Sun
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan
| | - Chao He
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Zhenghai Yang
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Shane J Goettl
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Tao Yang
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Bo-Yu Zhang
- 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
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
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3
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He C, Thomas AM, Dangi BB, Yang T, Kaiser RI, Lee HC, Sun BJ, Chang AHH. Formation of the Elusive Silylenemethyl Radical (HCSiH 2; X 2B 2) via the Unimolecular Decomposition of Triplet Silaethylene (H 2CSiH 2; a 3A″). J Phys Chem A 2022; 126:3347-3357. [PMID: 35584043 DOI: 10.1021/acs.jpca.2c01853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We investigated the formation of small organosilicon molecules─potential precursors to silicon-carbide dust grains ejected by dying carbon-rich asymptotic giant branch stars─in the gas phase via the reaction of atomic carbon (C) in its 3P electronic ground state with silane (SiH4; X1A1) using the crossed molecular beams technique. The reactants collided under single collision conditions at a collision energy of 13.0 ± 0.2 kJ mol-1, leading to the formation of the silylenemethyl radical (HCSiH2; X2B2) via the unimolecular decomposition of triplet silaethylene (H2CSiH2; a3A″). The silaethylene radical was formed via hydrogen migration of the triplet silylmethylene (HCSiH3; X3A″) radical, which in turn was identified as the initial collision complex accessed via the barrierless insertion of atomic carbon into the silicon-hydrogen bond of silane. Our results mark the first observation of the silylenemethyl radical, where previously only its thermodynamically more stable methylsilylidyne (CH3Si; X2A″) and methylenesilyl (CH2SiH; X2A') isomers were observed in low-temperature matrices. Considering the abundance of silane and the availability of atomic carbon in carbon-rich circumstellar environments, our results suggest that future astrochemical models should be updated to include contributions from small saturated organosilicon molecules as potential precursors to pure gaseous silicon-carbides and ultimately to silicon-carbide dust.
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Affiliation(s)
- Chao He
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Aaron M Thomas
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Beni B Dangi
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Tao Yang
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Huan-Cheng Lee
- 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
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Marcelino N, Tercero B, Agúndez M, Cernicharo J. A study of C 4H 3N isomers in TMC-1: line by line detection of HCCCH 2CN. ASTRONOMY AND ASTROPHYSICS 2021; 646:L9. [PMID: 33828332 PMCID: PMC7610538 DOI: 10.1051/0004-6361/202040177] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present Yebes 40m telescope observations of the three most stable C4H3N isomers towards the cyanopolyyne peak of TMC-1. We have detected 13 transitions from CH3C3N (A and E species), 16 lines from CH2CCHCN, and 27 lines (a-type and b-type) from HCCCH2CN. We thus provide a robust confirmation of the detection of HCCCH2CN and CH2CCHCN in space. We have constructed rotational diagrams for the three species, and obtained rotational temperatures between 4-8 K and similar column densities for the three isomers, in the range (1.5-3)×1012 cm-2. Our chemical model provides abundances of the order of the observed ones, although it overestimates the abundance of CH3CCCN and underestimates that of HCCCH2CN. The similarity of the observed abundances of the three isomers suggests a common origin, most probably involving reactions of the radical CN with the unsaturated hydrocarbons methyl acetylene and allene. Studies of reaction kinetics at low temperature and further observations of these molecules in different astronomical sources are needed to draw a clear picture of the chemistry of C4H3N isomers in space.
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Affiliation(s)
- N. Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental, CSIC, C/ Serrano 123, 28006 Madrid, Spain
| | - B. Tercero
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII 3, 28014 Madrid, Spain
- Observatorio de Yebes (IGN). Cerro de la Palera s/n, 19141 Yebes, Guadalajara, Spain
| | - M. Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental, CSIC, C/ Serrano 123, 28006 Madrid, Spain
| | - J. Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental, CSIC, C/ Serrano 123, 28006 Madrid, Spain
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5
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Doddipatla S, Galimova GR, Wei H, Thomas AM, He C, Yang Z, Morozov AN, Shingledecker CN, Mebel AM, Kaiser RI. Low-temperature gas-phase formation of indene in the interstellar medium. SCIENCE ADVANCES 2021; 7:7/1/eabd4044. [PMID: 33523847 PMCID: PMC7775774 DOI: 10.1126/sciadv.abd4044] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 11/04/2020] [Indexed: 06/07/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are fundamental molecular building blocks of fullerenes and carbonaceous nanostructures in the interstellar medium and in combustion systems. However, an understanding of the formation of aromatic molecules carrying five-membered rings-the essential building block of nonplanar PAHs-is still in its infancy. Exploiting crossed molecular beam experiments augmented by electronic structure calculations and astrochemical modeling, we reveal an unusual pathway leading to the formation of indene (C9H8)-the prototype aromatic molecule with a five-membered ring-via a barrierless bimolecular reaction involving the simplest organic radical-methylidyne (CH)-and styrene (C6H5C2H3) through the hitherto elusive methylidyne addition-cyclization-aromatization (MACA) mechanism. Through extensive structural reorganization of the carbon backbone, the incorporation of a five-membered ring may eventually lead to three-dimensional PAHs such as corannulene (C20H10) along with fullerenes (C60, C70), thus offering a new concept on the low-temperature chemistry of carbon in our galaxy.
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Affiliation(s)
- Srinivas Doddipatla
- Department of Chemistry, University of Hawai'i at Mānoa, Honolulu, HI 96822, USA
| | - Galiya R Galimova
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, 33199, USA
- Samara National Research University, Samara 443086, Russia
| | - Hongji Wei
- Department of Physics and Astronomy, Benedictine College, Atchison, KS 66002, USA
| | - Aaron M Thomas
- Department of Chemistry, University of Hawai'i at Mānoa, Honolulu, HI 96822, USA
| | - Chao He
- Department of Chemistry, University of Hawai'i at Mānoa, Honolulu, HI 96822, USA
| | - Zhenghai Yang
- Department of Chemistry, University of Hawai'i at Mānoa, Honolulu, HI 96822, USA
| | - Alexander N Morozov
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, 33199, USA
| | | | - Alexander M Mebel
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, 33199, USA.
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Mānoa, Honolulu, HI 96822, USA.
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6
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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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7
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He C, Thomas AM, Galimova GR, Mebel AM, Kaiser RI. Gas-Phase Formation of 1-Methylcyclopropene and 3-Methylcyclopropene via the Reaction of the Methylidyne Radical (CH; X 2Π) with Propylene (CH 3CHCH 2; X 1A'). J Phys Chem A 2019; 123:10543-10555. [PMID: 31718184 DOI: 10.1021/acs.jpca.9b09815] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The crossed molecular beam reactions of the methylidyne radical (CH; X2Π) with propylene (CH3CHCH2; X1A') along with (partially) substituted reactants were conducted at collision energies of 19.3 kJ mol-1. Combining our experimental data with ab initio electronic structure and statistical calculations, the methylidyne radical is revealed to add barrierlessly to the carbon-carbon double bond of propylene reactant resulting in a cyclic doublet C4H7 intermediate with a lifetime longer than its rotation period. These adducts undergo a nonstatistical unimolecular decomposition via atomic hydrogen loss through tight exit transition states forming the cyclic products 1-methylcyclopropene and 3-methylcyclopropene with overall reaction exoergicities of 168 ± 25 kJ mol-1. These C4H6 isomers are predicted to exist even in low-temperature environments such as cold molecular clouds like TMC-1, since the reaction is barrierless and exoergic, all transition states are below the energy of the separated reactants, and both the methylidyne radical (CH; X2Π) and propylene reactant were detected in cold molecular clouds such as TMC-1.
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Affiliation(s)
- Chao He
- Department of Chemistry , University of Hawai'i at Manoa , Honolulu , Hawaii 96822 , United States
| | - Aaron M Thomas
- 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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A Barrierless Pathway Accessing the C 9H 9 and C 9H 8 Potential Energy Surfaces via the Elementary Reaction of Benzene with 1-Propynyl. Sci Rep 2019; 9:17595. [PMID: 31772216 PMCID: PMC6879741 DOI: 10.1038/s41598-019-53987-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 11/07/2019] [Indexed: 11/16/2022] Open
Abstract
The crossed molecular beams reactions of the 1-propynyl radical (CH3CC; X2A1) with benzene (C6H6; X1A1g) and D6-benzene (C6D6; X1A1g) were conducted to explore the formation of C9H8 isomers under single-collision conditions. The underlying reaction mechanisms were unravelled through the combination of the experimental data with electronic structure and statistical RRKM calculations. These data suggest the formation of 1-phenyl-1-propyne (C6H5CCCH3) via the barrierless addition of 1-propynyl to benzene forming a low-lying doublet C9H9 intermediate that dissociates by hydrogen atom emission via a tight transition state. In accordance with our experiments, RRKM calculations predict that the thermodynamically most stable isomer – the polycyclic aromatic hydrocarbon (PAH) indene – is not formed via this reaction. With all barriers lying below the energy of the reactants, this reaction is viable in the cold interstellar medium where several methyl-substituted molecules have been detected. Its underlying mechanism therefore advances our understanding of how methyl-substituted hydrocarbons can be formed under extreme conditions such as those found in the molecular cloud TMC-1. Implications for the chemistry of the 1-propynyl radical in astrophysical environments are also discussed.
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He C, Zhao L, Thomas AM, Galimova GR, Mebel AM, Kaiser RI. A combined experimental and computational study on the reaction dynamics of the 1-propynyl radical (CH 3CC; X 2A 1) with ethylene (H 2CCH 2; X 1A 1g) and the formation of 1-penten-3-yne (CH 2CHCCCH 3; X 1A'). Phys Chem Chem Phys 2019; 21:22308-22319. [PMID: 31576858 DOI: 10.1039/c9cp04073k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The crossed molecular beam reactions of the 1-propynyl radical (CH3CC; X2A1) with ethylene (H2CCH2; X1A1g) and ethylene-d4 (D2CCD2; X1A1g) were performed at collision energies of 31 kJ mol-1 under single collision conditions. Combining our laboratory data with ab initio electronic structure and statistical Rice-Ramsperger-Kassel-Marcus (RRKM) calculations, we reveal that the reaction is initiated by the barrierless addition of the 1-propynyl radical to the π-electron density of the unsaturated hydrocarbon of ethylene leading to a doublet C5H7 intermediate(s) with a life time(s) longer than the rotation period(s). The reaction eventually produces 1-penten-3-yne (p1) plus a hydrogen atom with an overall reaction exoergicity of 111 ± 16 kJ mol-1. About 35% of p1 originates from the initial collision complex followed by C-H bond rupture via a tight exit transition state located 22 kJ mol-1 above the separated products. The collision complex (i1) can also undergo a [1,2] hydrogen atom shift to the CH3CHCCCH3 intermediate (i2) prior to a hydrogen atom release; RRKM calculations suggest that this pathway contributes to about 65% of p1. In higher density environments such as in combustion flames and circumstellar envelopes of carbon stars close to the central star, 1-penten-3-yne (p1) may eventually form the cyclopentadiene (c-C5H6) isomer via hydrogen atom assisted isomerization followed by hydrogen abstraction to the cyclopentadienyl radical (c-C5H5) as an important pathway to key precursors to polycyclic aromatic hydrocarbons (PAHs) and to carbonaceous nanoparticles.
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Affiliation(s)
- Chao He
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, USA.
| | - Long Zhao
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, USA.
| | - Aaron M Thomas
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, USA.
| | - Galiya R Galimova
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, USA. and Samara National Research University, Samara 443086, Russia
| | - Alexander M Mebel
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, USA. and Samara National Research University, Samara 443086, Russia
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, USA.
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He C, Zhao L, Thomas AM, Morozov AN, Mebel AM, Kaiser RI. Elucidating the Chemical Dynamics of the Elementary Reactions of the 1-Propynyl Radical (CH3CC; X2A1) with Methylacetylene (H3CCCH; X1A1) and Allene (H2CCCH2; X1A1). J Phys Chem A 2019; 123:5446-5462. [DOI: 10.1021/acs.jpca.9b03746] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- 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
| | - Aaron M. Thomas
- Department of Chemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United States
| | - Alexander N. Morozov
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - 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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11
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Thomas AM, Lucas M, Zhao L, Liddiard J, Kaiser RI, Mebel AM. A combined crossed molecular beams and computational study on the formation of distinct resonantly stabilized C 5H 3 radicals via chemically activated C 5H 4 and C 6H 6 intermediates. Phys Chem Chem Phys 2018. [PMID: 29537029 DOI: 10.1039/c8cp00357b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The crossed molecular beams technique was utilized to explore the formation of three isomers of resonantly stabilized (C5H3) radicals along with their d2-substituted counterparts via the bimolecular reactions of singlet/triplet dicarbon [C2(X1Σ+g/a3Πu)] with methylacetylene [CH3CCH(X1A1)], d3-methylacetylene [CD3CCH(X1A1)], and 1-butyne [C2H5CCH(X1A')] at collision energies up to 26 kJ mol-1via chemically activated singlet/triplet C5H4/C5D3H and C6H6 intermediates. These studies exploit a newly developed supersonic dicarbon [C2(X1Σ+g/a3Πu)] beam generated via photolysis of tetrachloroethylene [C2Cl4(X1Ag)] by excluding interference from carbon atoms, which represent the dominating (interfering) species in ablation-based dicarbon sources. We evaluated the performance of the dicarbon [C2(X1Σ+g/a3Πu)] beam in reactions with methylacetylene [CH3CCH(X1A1)] and d3-methylacetylene [CD3CCH(X1A1)]; the investigations demonstrate that the reaction dynamics match previous studies in our laboratory utilizing ablation-based dicarbon sources involving the synthesis of 1,4-pentadiynyl-3 [HCCCHCCH(X2B1)] and 2,4-pentadiynyl-1 [H2CCCCCH(X2B1)] radicals via hydrogen (deuterium) atom elimination. Considering the C2(X1Σ+g/a3Πu)-1-butyne [C2H5CCH(X1A')] reaction, the hitherto elusive methyl-loss pathway was detected. This channel forms the previously unknown resonantly stabilized penta-1-yn-3,4-dienyl-1 [H2CCCHCC(X2A)] radical along with the methyl radical [CH3(X2A2'')] and is open exclusively on the triplet surface with an overall reaction energy of -86 ± 10 kJ mol-1. The preferred reaction pathways proceed first by barrierless addition of triplet dicarbon to the π-electronic system of 1-butyne, either to both acetylenic carbon atoms or to the sterically more accessible carbon atom, to form the methyl-bearing triplet C6H6 intermediates [i41b] and [i81b], respectively, with the latter decomposing via a tight exit transition state to penta-1-yn-3,4-dienyl-1 [(H2CCCHCC(X2A)] plus the methyl radical [CH3(X2A2'')]. The successful unraveling of this methyl-loss channel - through collaborative experimental and computational efforts - underscores the viability of the photolytically generated dicarbon beam as an unprecedented tool to access reaction dynamics underlying the formation of resonantly stabilized free radicals (RSFR) that are vital to molecular mass growth processes that ultimately lead to polycyclic aromatic hydrocarbons (PAHs).
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Affiliation(s)
- Aaron M Thomas
- Department of Chemistry, University of Hawai'i at Mānoa, Honolulu, HI 96822, USA.
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12
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Custer T, Szczepaniak U, Gronowski M, Fabisiewicz E, Couturier-Tamburelli I, Kołos R. Density Functional Exploration of C4H3N Isomers. J Phys Chem A 2016; 120:5928-38. [PMID: 27341606 DOI: 10.1021/acs.jpca.6b03922] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecules having C4H3N stoichiometry are of astrophysical interest. Two of these, methylcyanoacetylene (CH3C3N) and its structural isomer allenyl cyanide (H2CCCHN), have been observed in interstellar space, while several more have been examined in laboratories. Here we describe, for a broad range of C4H3N isomers, density functional calculations (B3LYP/aug-cc-pVTZ) of molecular parameters including the energetics, geometries, rotational constants, electric dipole moments, polarizabilities, vibrational IR frequencies, IR absorption intensities, and Raman activities. Singlet-triplet splittings as well as singlet vertical electronic excitation energies are given for selected species. The identification of less stable C4H3N molecules, generated in ongoing spectroscopic experiments, relies heavily on these quantum chemical predictions.
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Affiliation(s)
- Thomas Custer
- Institute of Physical Chemistry, Polish Academy of Sciences , ul. Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Urszula Szczepaniak
- Institute of Physical Chemistry, Polish Academy of Sciences , ul. Kasprzaka 44/52, 01-224 Warsaw, Poland.,Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Sud, Université Paris-Saclay , F-91405 Orsay, France
| | - Marcin Gronowski
- Institute of Physical Chemistry, Polish Academy of Sciences , ul. Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Emilia Fabisiewicz
- Institute of Physical Chemistry, Polish Academy of Sciences , ul. Kasprzaka 44/52, 01-224 Warsaw, Poland
| | | | - Robert Kołos
- Institute of Physical Chemistry, Polish Academy of Sciences , ul. Kasprzaka 44/52, 01-224 Warsaw, Poland
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13
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Kerisit N, Rouxel C, Colombel-Rouen S, Toupet L, Guillemin JC, Trolez Y. Synthesis, Chemistry, and Photochemistry of Methylcyanobutadiyne in the Context of Space Science. J Org Chem 2016; 81:3560-7. [DOI: 10.1021/acs.joc.6b00205] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nicolas Kerisit
- Ecole Nationale
Supérieure de Chimie de Rennes, UMR 6226, CNRS, 11 allée de Beaulieu, CS
50837, 35708 Rennes cedex
7, France
| | - Cédric Rouxel
- Ecole Nationale
Supérieure de Chimie de Rennes, UMR 6226, CNRS, 11 allée de Beaulieu, CS
50837, 35708 Rennes cedex
7, France
| | - Sophie Colombel-Rouen
- Ecole Nationale
Supérieure de Chimie de Rennes, UMR 6226, CNRS, 11 allée de Beaulieu, CS
50837, 35708 Rennes cedex
7, France
| | - Loïc Toupet
- Institut de Physique
de Rennes, UMR 6251, CNRS, Université de Rennes 1, 263 avenue du Général
Leclerc, 35042 Rennes cedex, France
| | - Jean-Claude Guillemin
- Ecole Nationale
Supérieure de Chimie de Rennes, UMR 6226, CNRS, 11 allée de Beaulieu, CS
50837, 35708 Rennes cedex
7, France
| | - Yann Trolez
- Ecole Nationale
Supérieure de Chimie de Rennes, UMR 6226, CNRS, 11 allée de Beaulieu, CS
50837, 35708 Rennes cedex
7, France
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14
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Casavecchia P, Leonori F, Balucani N. Reaction dynamics of oxygen atoms with unsaturated hydrocarbons from crossed molecular beam studies: primary products, branching ratios and role of intersystem crossing. INT REV PHYS CHEM 2015. [DOI: 10.1080/0144235x.2015.1039293] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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15
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Maity S, Dangi BB, Parker DSN, Kaiser RI, Lin HM, E HP, Sun BJ, Chang AHH. Combined crossed molecular beam and ab initio investigation of the reaction of boron monoxide (BO; X(2)Σ(+)) with 1,3-butadiene (CH2CHCHCH2; X(1)Ag) and its deuterated counterparts. J Phys Chem A 2015; 119:1094-107. [PMID: 25626151 DOI: 10.1021/jp511715e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reactions of the boron monoxide ((11)BO; X(2)Σ(+)) radical with 1,3-butadiene (CH2CHCHCH2; X(1)Ag) and its partially deuterated counterparts, 1,3-butadiene-d2 (CH2CDCDCH2; X(1)Ag) and 1,3-butadiene-d4 (CD2CHCHCD2; X(1)Ag), were investigated under single collision conditions exploiting a crossed molecular beams machine. The experimental data were combined with the state-of-the-art ab initio electronic structure calculations and statistical RRKM calculations to investigate the underlying chemical reaction dynamics and reaction mechanisms computationally. Our investigations revealed that the reaction followed indirect scattering dynamics through the formation of (11)BOC4H6 doublet radical intermediates via the barrierless addition of the (11)BO radical to the terminal carbon atom (C1/C4) and/or the central carbon atom (C2/C3) of 1,3-butadiene. The resulting long-lived (11)BOC4H6 intermediate(s) underwent isomerization and/or unimolecular decomposition involving eventually at least two distinct atomic hydrogen loss pathways to 1,3-butadienyl-1-oxoboranes (CH2CHCHCH(11)BO) and 1,3-butadienyl-2-oxoboranes (CH2C ((11)BO)CHCH2) in overall exoergic reactions via tight exit transition states. Utilizing partially deuterated 1,3-butadiene-d2 and -d4, we revealed that the hydrogen loss from the methylene moiety (CH2) dominated with 70 ± 10% compared to an atomic hydrogen loss from the methylidyne group (CH) of only 30 ± 10%; these data agree nicely with the theoretically predicted branching ratio of 80% versus 19%.
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Affiliation(s)
- Surajit Maity
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States
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16
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Kirk BB, Savee JD, Trevitt AJ, Osborn DL, Wilson KR. Molecular weight growth in Titan's atmosphere: branching pathways for the reaction of 1-propynyl radical (H3CCC˙) with small alkenes and alkynes. Phys Chem Chem Phys 2015. [DOI: 10.1039/c5cp02589c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reaction of 1-propynyl radical with propyne and propene yields primarily methyl loss over hydrogen elimination. The implications of this result on molecular weight growth in Titan's atmosphere are discussed.
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Affiliation(s)
- Benjamin B. Kirk
- Chemical Sciences Division
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
| | - John D. Savee
- Combustion Research Facility
- Sandia National Laboratories
- Livermore
- USA
| | | | - David L. Osborn
- Combustion Research Facility
- Sandia National Laboratories
- Livermore
- USA
| | - Kevin R. Wilson
- Chemical Sciences Division
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
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17
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Maity S, Dangi BB, Parker DSN, Kaiser RI, An Y, Sun BJ, Chang AHH. Combined crossed molecular beam and ab initio investigation of the multichannel reaction of boron monoxide (BO; X2Σ+) with Propylene (CH3CHCH2; X1A'): competing atomic hydrogen and methyl loss pathways. J Phys Chem A 2014; 118:9632-45. [PMID: 25238644 DOI: 10.1021/jp507001r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The reaction dynamics of boron monoxide ((11)BO; X(2)Σ(+)) with propylene (CH(3)CHCH(2); X(1)A') were investigated under single collision conditions at a collision energy of 22.5 ± 1.3 kJ mol(-1). The crossed molecular beam investigation combined with ab initio electronic structure and statistical (RRKM) calculations reveals that the reaction follows indirect scattering dynamics and proceeds via the barrierless addition of boron monoxide radical with its radical center located at the boron atom. This addition takes place to either the terminal carbon atom (C1) and/or the central carbon atom (C2) of propylene reactant forming (11)BOC(3)H(6) intermediate(s). The long-lived (11)BOC(3)H(6) doublet intermediate(s) underwent unimolecular decomposition involving at least three competing reaction mechanisms via an atomic hydrogen loss from the vinyl group, an atomic hydrogen loss from the methyl group, and a methyl group elimination to form cis-/trans-1-propenyl-oxo-borane (CH(3)CHCH(11)BO), 3-propenyl-oxo-borane (CH(2)CHCH(2)(11)BO), and ethenyl-oxo-borane (CH(2)CH(11)BO), respectively. Utilizing partially deuterated propylene (CD(3)CHCH(2) and CH(3)CDCD(2)), we reveal that the loss of a vinyl hydrogen atom is the dominant hydrogen elimination pathway (85 ± 10%) forming cis-/trans-1-propenyl-oxo-borane, compared to the loss of a methyl hydrogen atom (15 ± 10%) leading to 3-propenyl-oxo-borane. The branching ratios for an atomic hydrogen loss from the vinyl group, an atomic hydrogen loss from the methyl group, and a methyl group loss are experimentally derived to be 26 ± 8%:5 ± 3%:69 ± 15%, respectively; these data correlate nicely with the branching ratios calculated via RRKM theory of 19%:5%:75%, respectively.
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Affiliation(s)
- Surajit Maity
- Department of Chemistry, University of Hawaii at Manoa , Honolulu, Hawaii 96822, United States
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18
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Sun BJ, Huang CH, Chen SY, Chen SH, Kaiser RI, Chang AHH. Theoretical Study on Reaction Mechanism of Ground-State Cyano Radical with 1,3-Butadiene: Prospect of Pyridine Formation. J Phys Chem A 2014; 118:7715-24. [DOI: 10.1021/jp5056864] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- B. J. Sun
- Department
of Chemistry, National Dong Hwa University, No.1 Sec. 2 Da Hsueh Road, Shoufeng, Hualien 974, Taiwan
| | - C. H. Huang
- Department
of Chemistry, National Dong Hwa University, No.1 Sec. 2 Da Hsueh Road, Shoufeng, Hualien 974, Taiwan
| | - S. Y. Chen
- Department
of Chemistry, National Dong Hwa University, No.1 Sec. 2 Da Hsueh Road, Shoufeng, Hualien 974, Taiwan
| | - S. H. Chen
- Department
of Chemistry, National Dong Hwa University, No.1 Sec. 2 Da Hsueh Road, Shoufeng, Hualien 974, Taiwan
| | - R. I. Kaiser
- Department
of Chemistry, University of Hawaii at Manoa, 2545 McCarthy Mall, Honolulu, Hawaii 96822, United States
| | - A. H. H. Chang
- Department
of Chemistry, National Dong Hwa University, No.1 Sec. 2 Da Hsueh Road, Shoufeng, Hualien 974, Taiwan
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19
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Reaction dynamics and relative yields of the H- and CH3-displacement channels in the O+CH3CCH reaction. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.04.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Parker DSN, Mebel AM, Kaiser RI. The role of isovalency in the reactions of the cyano (CN), boron monoxide (BO), silicon nitride (SiN), and ethynyl (C2H) radicals with unsaturated hydrocarbons acetylene (C2H2) and ethylene (C2H4). Chem Soc Rev 2014; 43:2701-13. [DOI: 10.1039/c3cs60328h] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The classification of chemical reactions based on shared characteristics is at the heart of the chemical sciences, and is well exemplified by Langmuir's concept of isovalency, in which ‘two molecular entities with the same number of valence electrons have similar chemistries’.
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Affiliation(s)
- D. S. N. Parker
- Department of Chemistry
- University of Hawai'i at Manoa
- Honolulu, USA
| | - A. M. Mebel
- Department of Chemistry and Biochemistry
- Florida International University
- Miami, USA
| | - R. I. Kaiser
- Department of Chemistry
- University of Hawai'i at Manoa
- Honolulu, USA
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21
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Jamal A, Mebel AM. Theoretical Investigation of the Mechanism and Product Branching Ratios of the Reactions of Cyano Radical with 1- and 2-Butyne and 1,2-Butadiene. J Phys Chem A 2013; 117:741-55. [DOI: 10.1021/jp3091045] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Adeel Jamal
- Department of Chemistry and Biochemistry, Florida International University, Florida 33199, United
States
| | - Alexander M. Mebel
- Department of Chemistry and Biochemistry, Florida International University, Florida 33199, United
States
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22
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Parker DSN, Wilson AV, Kaiser RI, Labrador T, Mebel AM. Gas-Phase Synthesis of the Silaisocyanoethylene Molecule (C2H3NSi). J Org Chem 2012; 77:8574-80. [DOI: 10.1021/jo3015402] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- D. S. N. Parker
- Department of Chemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United States
| | - A. V. Wilson
- Department of Chemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United States
| | - R. I. Kaiser
- Department of Chemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United States
| | - T. Labrador
- Department of Chemistry
and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - A. M. Mebel
- Department of Chemistry
and Biochemistry, Florida International University, Miami, Florida 33199, United States
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23
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Kaiser RI, Mebel AM. On the formation of polyacetylenes and cyanopolyacetylenes in Titan's atmosphere and their role in astrobiology. Chem Soc Rev 2012; 41:5490-501. [DOI: 10.1039/c2cs35068h] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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24
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Leonori F, Hickson KM, Le Picard SD, Wang X, Petrucci R, Foggi P, Balucani N, Casavecchia P. Crossed-beam universal-detection reactive scattering of radical beams characterized by laser-induced-fluorescence: the case of C2and CN. Mol Phys 2010. [DOI: 10.1080/00268971003657110] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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25
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Berteloite C, Le Picard SD, Balucani N, Canosa A, Sims IR. Low temperature rate coefficients for reactions of the butadiynyl radical, C4H, with various hydrocarbons. Part II: reactions with alkenes (ethylene, propene, 1-butene), dienes (allene, 1,3-butadiene) and alkynes (acetylene, propyne and 1-butyne). Phys Chem Chem Phys 2010; 12:3677-89. [DOI: 10.1039/b923867k] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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26
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Kaiser RI, Maksyutenko P, Ennis C, Zhang F, Gu X, Krishtal SP, Mebel AM, Kostko O, Ahmed M. Untangling the chemical evolution of Titan's atmosphere and surface–from homogeneous to heterogeneous chemistry. Faraday Discuss 2010; 147:429-78; discussion 527-52. [DOI: 10.1039/c003599h] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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27
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Huang CH, Kaiser RI, Chang AHH. Theoretical Study on the Reaction of Ground State Cyano Radical with Propylene in Titan’s Atmosphere. J Phys Chem A 2009; 113:12675-85. [DOI: 10.1021/jp905081u] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- C. H. Huang
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan, and Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822
| | - R. I. Kaiser
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan, and Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822
| | - A. H. H. Chang
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan, and Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822
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28
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Balucani N. Elementary reactions and their role in gas-phase prebiotic chemistry. Int J Mol Sci 2009; 10:2304-2335. [PMID: 19564951 PMCID: PMC2695279 DOI: 10.3390/ijms10052304] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2009] [Revised: 05/13/2009] [Accepted: 05/15/2009] [Indexed: 11/23/2022] Open
Abstract
The formation of complex organic molecules in a reactor filled with gaseous mixtures possibly reproducing the primitive terrestrial atmosphere and ocean demonstrated more than 50 years ago that inorganic synthesis of prebiotic molecules is possible, provided that some form of energy is provided to the system. After that groundbreaking experiment, gas-phase prebiotic molecules have been observed in a wide variety of extraterrestrial objects (including interstellar clouds, comets and planetary atmospheres) where the physical conditions vary widely. A thorough characterization of the chemical evolution of those objects relies on a multi-disciplinary approach: 1) observations allow us to identify the molecules and their number densities as they are nowadays; 2) the chemistry which lies behind their formation starting from atoms and simple molecules is accounted for by complex reaction networks; 3) for a realistic modeling of such networks, a number of experimental parameters are needed and, therefore, the relevant molecular processes should be fully characterized in laboratory experiments. A survey of the available literature reveals, however, that much information is still lacking if it is true that only a small percentage of the elementary reactions considered in the models have been characterized in laboratory experiments. New experimental approaches to characterize the relevant elementary reactions in laboratory are presented and the implications of the results are discussed.
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Affiliation(s)
- Nadia Balucani
- Dipartimento di Chimica, Università degli Studi di Perugia, 06123 Perugia, Italy; E-Mail:
; Tel. +39-075-585-5513; Fax: +39-075-585-5606
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29
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Huang C, Li W, Estillore AD, Suits AG. Dynamics of CN+alkane reactions by crossed-beam dc slice imaging. J Chem Phys 2009; 129:074301. [PMID: 19044761 DOI: 10.1063/1.2968547] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The hydrogen atom abstraction reactions of CN (X (2)Sigma(+)) with alkanes have been studied using the crossed molecular beam technique with dc slice ion imaging at collision energies of 7.5 and 10.8 kcalmol. The product alkyl radical images were obtained via single photon ionization at 157 nm for the reactions of CN (X (2)Sigma(+)) with n-butane, n-pentane, n-hexane, and cyclohexane. From analysis of the images, we obtained the center-of-mass frame product angular distributions and translational energy distributions directly. The results indicate that the products are largely backscattered and that most of the available energy ( approximately 80%-85%) goes to the internal energy of the products. The reaction dynamics is discussed in light of recent kinetics data, theoretical calculations, and results for related halogen and oxygen atom reactions.
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Affiliation(s)
- Cunshun Huang
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA
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30
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Gu X, Zhang F, Kaiser RI. Reaction dynamics on the formation of 1- and 3-cyanopropylene in the crossed beams reaction of ground-state cyano radicals (CN) with propylene (C3H6) and its deuterated isotopologues. J Phys Chem A 2008; 112:9607-13. [PMID: 18681396 DOI: 10.1021/jp8039059] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Crossed molecular beams experiments were utilized to explore the chemical reaction dynamics of ground-state cyano radicals, CN(X(2)Sigma(+)), with propylene (CH3CHCH2) together with two d3-isotopologues (CD3CHCH2, CH3CDCD2) as potential pathways to form organic nitriles under single collision conditions in the atmosphere of Saturn's moon Titan and in the interstellar medium. On the basis of the center-of-mass translational and angular distributions, the reaction dynamics were deduced to be indirect and commenced via an addition of the electrophilic cyano radical with its radical center to the alpha-carbon atom of the propylene molecule yielding a doublet radical intermediate: CH3CHCH2CN. Crossed beam experiments with propylene-1,1,2-d3 (CH3CDCD2) and propylene-3,3,3-d3 (CD3CHCH2) indicated that the reaction intermediates CH3CDCD2CN (from propylene-1,1,2-d3) and CD3CHCH2CN (from propylene-3,3,3-d3) eject both atomic hydrogen through tight exit transition states located about 40-50 kJ mol(-1) above the separated products: 3-butenenitrile [H2CCDCD2CN] (25%), and cis/trans-2-butenenitrile [CD3CHCHCN] (75%), respectively, plus atomic hydrogen. Applications of our results to the chemical processing of cold molecular clouds like TMC-1 and OMC-1 are also presented.
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Affiliation(s)
- Xibin Gu
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA
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31
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Gu X, Guo Y, Zhang F, Mebel AM, Kaiser RI. Unimolecular decomposition of chemically activated singlet and triplet D3-methyldiacetylene molecules. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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32
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Guo Y, Mebel AM, Zhang F, Gu X, Kaiser RI. Crossed molecular beam studies of the reactions of allyl radicals, C3H5(X2A2), with methylacetylene (CH3CCH(X1A1)), allene (H2CCCH2(X1A1)), and their isotopomers. J Phys Chem A 2007; 111:4914-21. [PMID: 17516638 DOI: 10.1021/jp0714466] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The chemical dynamics of the reaction of allyl radicals, C(3)H(5)(X(2)A(2)), with two C(3)H(4) isomers, methylacetylene (CH(3)CCH(X(1)A(1))) and allene (H(2)CCCH(2)(X(1)A(1))) together with their (partially) deuterated counterparts, were unraveled under single-collision conditions at collision energies of about 125 kJ mol(-1) utilizing a crossed molecular beam setup. The experiments indicate that the reactions are indirect via complex formation and proceed via an addition of the allyl radical with its terminal carbon atom to the terminal carbon atom of the allene and of methylacetylene (alpha-carbon atom) to form the intermediates H(2)CCHCH(2)CH(2)CCH(2) and H(2)CCHCH(2)CHCCH(3), respectively. The lifetimes of these intermediates are similar to their rotational periods but too short for a complete energy randomization to occur. Experiments with D4-allene and D4-methylacetylene verify explicitly that the allyl group stays intact: no hydrogen emission was observed but only the release of deuterium atoms from the perdeuterated reactants. Further isotopic substitution experiments with D3-methylacetylene combined with the nonstatistical nature of the reaction suggest that the intermediates decompose via hydrogen atom elimination to 1,3,5-hexatriene, H(2)CCHCH(2)CHCCH(2), and 1-hexen-4-yne, H(2)CCHCH(2)CCCH(3), respectively, via tight exit transition states located about 10-15 kJ mol(-1) above the separated products. The overall reactions were found to be endoergic by 98 +/- 4 kJ mol(-1) and have characteristic threshold energies to reaction between 105 and 110 kJ mol(-1). Implications of these findings to combustion and interstellar chemistry are discussed.
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Affiliation(s)
- Y Guo
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA
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33
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Li HY, Cheng WC, Liu YL, Sun BJ, Huang CY, Chen KT, Tang MS, Kaiser RI, Chang AHH. Reaction of cyanoacetylene HCCCN(XΣ+1) with ground-state carbon atoms C(P3) in cold molecular clouds. J Chem Phys 2006; 124:044307. [PMID: 16460162 DOI: 10.1063/1.2148411] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The reaction of the simplest cyanopolyyne, cyanoacetylene [HCCCN(X (1)Sigma(+))], with ground-state atomic carbon C((3)P) is investigated theoretically to explore the probable routes for the depletion of the famed interstellar molecule HCCCN, and the formation of carbon-nitrogen-bearing species in extraterrestrial environments particularly of ultralow temperature. Six collision complexes (c1-c6) without entrance barrier as a result of the carbon atom addition to the pi systems of HCCCN are located. The optimized geometries and harmonic frequencies of the intermediates, transition states, and products along the isomerization and dissociation pathways of each collision complex are obtained by utilizing the unrestricted B3YLP6-311G(d,p) level of theory, and the corresponding CCSD(T)/cc-pVTZ energies are calculated. Subsequently, with the facilitation of Rice-Ramsperger-Kassel-Marcus (RRKM) and variational RRKM rate constants at collision energy of 0-10 kcal/mol, the most probable paths for the titled reaction are determined, and the product yields are estimated. Five collision complexes (c1-c3, c5, and c6) are predicted to give the same products, a chained CCCCN (p2)+H, via the linear and most stable intermediate, HCCCCN (i2), while collision complex c4 is likely to dissociate back to C+HCCCN. The study suggests that this class of reaction is an important route to the destruction of cyanoacetylene and cyanopolyynes in general, and to the synthesis of linear carbon-chained nitriles at the temperature as low as 10 K to be incorporated in future chemical models of interstellar clouds.
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Affiliation(s)
- H Y Li
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan, Republic of China
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34
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Guo Y, Gu X, Zhang F, Tang MS, Sun BJ, H Chang AH, Kaiser RI. A crossed beams study of the reaction of carbon atoms, C(3Pj), with vinyl cyanide, C2H3CN(X1A′)—investigating the formation of cyano propargyl radicals. Phys Chem Chem Phys 2006; 8:5454-61. [PMID: 17119654 DOI: 10.1039/b611936k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The chemical dynamics of the reaction of ground state carbon atoms, C(3Pj), with vinyl cyanide, C2H3CN(X 1A'), were examined under single collision conditions at collision energies of 29.9 and 43.9 kJ mol(-1) using the crossed molecular beams approach. The experimental studies were combined with electronic structure calculations on the triplet C4H3N potential energy surface (H. F. Su, R. I. Kaiser, A. H. H. Chang, J. Chem. Phys., 2005, 122, 074320). Our investigations suggest that the reaction follows indirect scattering dynamics via addition of the carbon atom to the carbon-carbon double bond of the vinyl cyanide molecule yielding a cyano cyclopropylidene collision complex. The latter undergoes ring opening to form cis/trans triplet cyano allene which fragments predominantly to the 1-cyano propargyl radical via tight exit transition states; the 3-cyano propargyl isomer was inferred to be formed at least a factor of two less; also, no molecular hydrogen elimination channel was observed experimentally. These results are in agreement with the computational studies predicting solely the existence of a carbon versus hydrogen atom exchange pathway and the dominance of the 1-cyano propargyl radical product. The discovery of the cyano propargyl radical in the reaction of atomic carbon with vinyl cyanide under single collision conditions implies that this molecule can be an important reaction intermediate in combustion flames and also in extraterrestrial environments (cold molecular clouds, circumstellar envelopes of carbon stars) which could lead to the formation of cyano benzene (C6H5CN) upon reaction with a propargyl radical.
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Affiliation(s)
- Y Guo
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, HI 96822, USA
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Daugey N, Caubet P, Retail B, Costes M, Bergeat A, Dorthe G. Kinetic measurements on methylidyne radical reactions with several hydrocarbons at low temperatures. Phys Chem Chem Phys 2005; 7:2921-7. [PMID: 16189612 DOI: 10.1039/b506096f] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The temperature dependences of the methylidyne radical reactions with methane, allene, methylacetylene and propene were studied. This work was carried out in a supersonic flow reactor coupled with pulsed laser photolysis (PLP) and laser-induced fluorescence (LIF) techniques. Three Laval nozzles were designed to provide uniform supersonic expansions of nitrogen at Mach 2 and of argon at Mach 2 and 3 to reach low temperatures, e.g. 170, 128 and 77 K, respectively. CH radicals were produced by PLP of CHBr3 at 266 nm and probed by LIF. The exponential decays of the CH fluorescence were acquired, hydrocarbons being introduced in excess. The rate constants for the CH+CH4 reaction are in good agreement with the temperature dependence proposed by Canosa et al. (A. Canosa, I. R. Sims, D. Travers, I. W. M. Smith and B. R. Rowe, Astron. Astrophys., 1997, 323, 644-651, ) i.e. 3.96x10(-8)(T/K)(-1.04) exp(-36.1 K/T) in the range 23-298 K. The rate constants of the CH+C3H4(allene), CH+C3H4(methylacetylene) and CH+C3H6(propene) reactions exhibit a small temperature dependence between 77 and 170 K, with a maximum rate around 100 K close to (4.3-4.6)x10(-10) cm3 molecule-1 s-1.
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Affiliation(s)
- Nicolas Daugey
- Laboratoire de Physico-Chimie Moléculaire, CNRS UMR5803, Université Bordeaux 1, F-33405, Talence Cedex, France
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Su HF, Kaiser RI, Chang AHH. A theoretical study for the reaction of vinyl cyanide C2H3CN(XA′1) with the ground state carbon atom C(P3) in cold molecular clouds. J Chem Phys 2005; 122:074320. [PMID: 15743245 DOI: 10.1063/1.1846672] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The reaction of the ground state atomic carbon, C(3P), with simple unsaturated nitrile, C2H3CN(X1A' (vinyl cyanide), is investigated theoretically to explore the probable routes for the formation of carbon-nitrogen-bearing species in extraterrestrial environments particularly of ultralow temperature. Five collision complexes without entrance barrier as a result of the carbon atom addition to the pi systems of C2H3CN are characterized. The B3YLP/6-311G(d,p) level of theory is utilized in obtaining the optimized geometries, harmonic frequencies, and energies of the intermediates, transition states, and products along the isomerization and dissociation pathways of each collision complex. Subsequently, with the facilitation of computed RRKM rate constants at collision energy of 0-10 kcal/mol, the most probable paths for each collision complexes are determined, of which the CCSD(T)/6-311G(d,p) energies are calculated. The major products predicted are exclusively due to the hydrogen atom dissociations, while the products of H2, CN, and CH2 decompositions are found negligible. Among many possible H-elimination products, cyano propargyl (p4) and 3-cyano propargyl (p5) are the most probable, in which p5 can be formed via two intermediates, cyano allene (i8) and cyano vinylmethylene (i6), while p4 is yielded from i8. The study suggests this class of reaction is an important route to the synthesis of unsaturated nitriles at the temperature as low as 10 K, and the results are valuable for future chemical models of interstellar clouds.
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Affiliation(s)
- Hsiu-Fen Su
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan, Republic of China
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Di Stefano M, Rosi M, Sgamellotti A, Negri F. Reactions of N+ ions with benzene: a theoretical study on the C6NH6+ potential energy surface. Chem Phys 2004. [DOI: 10.1016/j.chemphys.2004.04.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Reactions of N+ ions with ethylene: a theoretical study on the addition mechanism into the olefin double bond. Chem Phys 2004. [DOI: 10.1016/j.chemphys.2003.10.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Di Stefano M, Rosi M, Sgamellotti A, Ascenzi D, Bassi D, Franceschi P, Tosi P. Experimental and theoretical investigation of the production of cations containing C–N bonds in the reaction of benzene with atomic nitrogen ions. J Chem Phys 2003. [DOI: 10.1063/1.1582836] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Carty D, Le Page V, Sims IR, Smith IW. Low temperature rate coefficients for the reactions of CN and C2H radicals with allene (CH2CCH2) and methyl acetylene (CH3CCH). Chem Phys Lett 2001. [DOI: 10.1016/s0009-2614(01)00682-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Basiuk VA. Formation of Amino Acid Precursors in the Interstellar Medium. A DFT Study of Some Gas-Phase Reactions Starting with Methylenimine. J Phys Chem A 2001. [DOI: 10.1021/jp004116t] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vladimir A. Basiuk
- Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior C.U.; A. Postal 70−543, 04510 México D.F., Mexico
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Balucani N, Asvany O, Chang AHH, Lin SH, Lee YT, Kaiser RI, Osamura Y. Crossed beam reaction of cyano radicals with hydrocarbon molecules. III. Chemical dynamics of vinylcyanide (C2H3CN;X 1A′) formation from reaction of CN(X 2Σ+) with ethylene, C2H4(X 1Ag). J Chem Phys 2000. [DOI: 10.1063/1.1289529] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Kaiser RI, Asvany O, Lee YT, Bettinger HF, Schleyer PVR, Schaefer HF. Crossed beam reaction of phenyl radicals with unsaturated hydrocarbon molecules. I. Chemical dynamics of phenylmethylacetylene (C6H5CCCH3;X 1A′) formation from reaction of C6H5(X 2A1) with methylacetylene, CH3CCH(X 1A1). J Chem Phys 2000. [DOI: 10.1063/1.481054] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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