1
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Thimmakondu VS, Karton A. CCSD(T) Rotational Constants for Highly Challenging C 5H 2 Isomers-A Comparison between Theory and Experiment. Molecules 2023; 28:6537. [PMID: 37764314 PMCID: PMC10537648 DOI: 10.3390/molecules28186537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 09/06/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
We evaluate the accuracy of CCSD(T) and density functional theory (DFT) methods for the calculation of equilibrium rotational constants (Ae, Be, and Ce) for four experimentally detected low-lying C5H2 isomers (ethynylcyclopropenylidene (2), pentatetraenylidene (3), ethynylpropadienylidene (5), and 2-cyclopropen-1-ylidenethenylidene (8)). The calculated rotational constants are compared to semi-experimental rotational constants obtained by converting the vibrationally averaged experimental rotational constants (A0, B0, and C0) to equilibrium values by subtracting the vibrational contributions (calculated at the B3LYP/jun-cc-pVTZ level of the theory). The considered isomers are closed-shell carbenes, with cumulene, acetylene, or strained cyclopropene moieties, and are therefore highly challenging from an electronic structure point of view. We consider both frozen-core and all-electron CCSD(T) calculations, as well as a range of DFT methods. We find that calculating the equilibrium rotational constants of these C5H2 isomers is a difficult task, even at the CCSD(T) level. For example, at the all-electron CCSD(T)/cc-pwCVTZ level of the theory, we obtain percentage errors ≤0.4% (Ce of isomer 3, Be and Ce of isomer 5, and Be of isomer 8) and 0.9-1.5% (Be and Ce of isomer 2, Ae of isomer 5, and Ce of isomer 8), whereas for the Ae rotational constant of isomers 2 and 8 and Be rotational constant of isomer 3, high percentage errors above 3% are obtained. These results highlight the challenges associated with calculating accurate rotational constants for isomers with highly challenging electronic structures, which is further complicated by the need to convert vibrationally averaged experimental rotational constants to equilibrium values. We use our best CCSD(T) rotational constants (namely, ae-CCSD(T)/cc-pwCVTZ for isomers 2 and 5, and ae-CCSD(T)/cc-pCVQZ for isomers 3 and 8) to evaluate the performance of DFT methods across the rungs of Jacob's Ladder. We find that the considered pure functionals (BLYP-D3BJ, PBE-D3BJ, and TPSS-D3BJ) perform significantly better than the global and range-separated hybrid functionals. The double-hybrid DSD-PBEP86-D3BJ method shows the best overall performance, with percentage errors below 0.5% in nearly all cases.
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Affiliation(s)
- Venkatesan S Thimmakondu
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA 92182-1030, USA
| | - Amir Karton
- School of Science and Technology, University of New England, Armidale, NSW 2351, Australia
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2
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Li W, Zhao L, Kaiser RI. A unified reaction network on the formation of five-membered ringed polycyclic aromatic hydrocarbons (PAHs) and their role in ring expansion processes through radical-radical reactions. Phys Chem Chem Phys 2023; 25:4141-4150. [PMID: 36655590 DOI: 10.1039/d2cp05305e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Exploiting a chemical microreactor in combination with an isomer-selective product identification through fragment-free photoionization utilizing tunable vacuum ultraviolet (VUV) light in tandem with the detection of the ionized molecules by a high resolution reflection time-of-flight mass spectrometer (Re-TOF-MS), the present investigation reveals molecular mass growth processes to four distinct polycyclic aromatic hydrocarbons carrying two six- and one five-membered ring (C13H10): 3H-cyclopenta[a]naphthalene, 1H-cyclopenta[b]naphthalene, 1H-cyclopenta[a]naphthalene, and fluorene in the gas phase. Temperatures of 973 and 1023 K simulating conditions in combustion settings along with circumstellar envelopes of carbon-rich stars and planetary nebulae. These reactions highlight the importance of methyl-substituted aromatic reactants (biphenyl, naphthalene) which can be converted to the methylene (-CH2˙) motive by hydrogen abstraction or photolysis. Upon reaction with acetylene, methylene-substituted aromatics carrying a hydrogen atom at the ortho position of the ring can be then converted to cyclopentadiene-annulated aromatics thus providing a versatile pathway to five-membered ring aromatics at elevated temperatures.
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Affiliation(s)
- Wang Li
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China.
| | - Long Zhao
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China. .,School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
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3
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Roy T, Thimmakondu VS, Ghosal S. New Carbenes and Cyclic Allenes Energetically Comparable to Experimentally Known 1-Azulenylcarbene. ACS OMEGA 2022; 7:30149-30160. [PMID: 36061723 PMCID: PMC9435053 DOI: 10.1021/acsomega.2c03224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 08/09/2022] [Indexed: 06/15/2023]
Abstract
1-Azulenylcarbene (18; 0 kJ mol-1) is experimentally known as the key reactive intermediate for the rearrangement reactions of aryl carbenes in the laboratory. Here, using coupled-cluster methods up to the fc-CCSD(T)/cc-pVTZ//fc-CCSD(T)/cc-pVDZ level, thirteen new carbenes and one new cyclic allene are theoretically identified within the C11H8 elemental composition that either energetically lie below or very close to 18. While the cyclic allene, bicyclo[5.4.0]undeca-2,3,5,7,9,11-hexene (1; -166 kJ mol-1), is the experimentally known lowest energy isomer, three other cyclic allenes, bicyclo[5.4.0]undeca-1,2,4,6,8,10-hexene (2; -100 kJ mol-1), bicyclo[5.4.0]undeca-1,3,4,6,8,10-hexene (3; -97 kJ mol-1), and bicyclo[6.3.0]undeca-1,2,4,6,8,10-hexene (13; -42 kJ mol-1), demand new experimental studies. In total, thirty-one isomers are studied in this work (within -166 to +15 kJ mol-1 from 18) and all are found to be polar (μ ≠ 0). Among these, 1H-benzo[7]annulen-1-ylidene (17; -4 kJ mol-1; μ = 5.24 D), bicyclo[5.4.0]undeca-2,4,6,8,11-pentaene-10-ylidene (24; 13 kJ mol-1; μ = 7.59 D), 5-methylene-naphthalen-1-ylidene (26; 15 kJ mol-1; μ = 5.32 D), 6-methylene-naphthalen-2-ylidene (27; -43 kJ mol-1; μ = 6.60 D), and 8-methylene-naphthalen-2-ylidene (28; -39 kJ mol-1; μ = 5.55 D) are competitively polar compared to 18 (μ = 5.39 D). Therefore, these carbene molecules are potential targets for rotational spectroscopists and radioastronomers. Considering the importance of naphthyl and azulenylcarbenes in reactive intermediate chemistry, mechanisms of different rearrangement reactions and plausible formation pathways of some of these new carbenes are studied in this work using density functional theory.
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Affiliation(s)
- Tarun Roy
- Department
of Chemistry, National Institute of Technology
Durgapur, M G Avenue, Durgapur 713
209, India
| | - Venkatesan S. Thimmakondu
- Department
of Chemistry and Biochemistry, San Diego
State University, San Diego, California 92182-1030, United States
| | - Subhas Ghosal
- Department
of Chemistry, National Institute of Technology
Durgapur, M G Avenue, Durgapur 713
209, India
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4
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Karton A, Thimmakondu VS. From Molecules with a Planar Tetracoordinate Carbon to an Astronomically Known C 5H 2 Carbene. J Phys Chem A 2022; 126:2561-2568. [PMID: 35426667 PMCID: PMC9442649 DOI: 10.1021/acs.jpca.2c01261] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Ethynylcyclopropenylidene
(2), an isomer of C5H2, is a known
molecule in the laboratory and has
recently been identified in Taurus Molecular Cloud-1 (TMC-1). Using
high-level coupled-cluster methods up to the CCSDT(Q)/CBS level of
theory, it is shown that two isomers of C5H2 with a planar tetracoordinate carbon (ptC) atom, (SP-4)-spiro[2.2]pent-1,4-dien-1,4-diyl
(11) and (SP-4)-spiro[2.2]pent-1,4-dien-1,5-diyl (13), serve as the reactive intermediates for the formation
of 2. Here, a theoretical connection has been established
between molecules containing ptC atoms (11 and 13) and a molecule (2) that is present nearly
430 light years away, thus providing evidence for the existence of
ptC species in the interstellar medium. The reaction pathways connecting
the transition states and the reactants and products have been confirmed
by intrinsic reaction coordinate calculations at the CCSDT(Q)/CBS//B3LYP-D3BJ/cc-pVTZ
level. While isomer 11 is non-polar (μ = 0), isomers 2 and 13 are polar, with dipole moment values
of 3.52 and 5.17 Debye at the CCSD(T)/cc-pVTZ level. Therefore, 13 is also a suitable candidate for both laboratory and radioastronomical
studies.
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Affiliation(s)
- Amir Karton
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - Venkatesan S Thimmakondu
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92182-1030, USA
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5
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Nikolayev AA, Azyazov VN, Kaiser RI, Mebel AM. Theoretical Study of the Reaction of the Methylidyne Radical (CH; X 2Π) with 1-Butyne (CH 3CH 2CCH; X 1A'). J Phys Chem A 2021; 125:9536-9547. [PMID: 34672597 DOI: 10.1021/acs.jpca.1c07519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ab initio CCSD(T)-F12/cc-pVTZ-f12//ωB97X-D/6-311G(d,p) + ZPE[ωB97X-D/6-311G(d,p)] calculations were carried out to unravel the area of the C5H7 potential energy surface accessed by the reaction of the methylidyne radical with 1-butyne. The results were utilized in Rice-Ramsperger-Kassel-Marcus calculations of the product branching ratios at the zero pressure limit. The preferable reaction mechanism has been shown to involve (nearly) instantaneous decomposition of the initial reaction adducts, whose structures are controlled by the isomeric form of the C4H6 reactant. If CH adds to the triple C≡C bond in the entrance reaction channel, the reaction is predicted to predominantly form the methylenecyclopropene + methyl (CH3) and cyclopropenylidene + ethyl (C2H5) products roughly in a 2:1 ratio. CH insertion into a C-H bond in the methyl group of 1-butyne is anticipated to preferentially form ethylene + propargyl (C3H3) by the C-C bond β-scission in the initial complex, whereas CH insertion into C-H of the CH2 group would predominantly produce vinylacetylene + methyl (CH3) also by the C-C bond β-scission in the adduct. The barrierless and highly exoergic CH + 1-butyne reaction, facile in cold molecular clouds, is not likely to lead to the carbon skeleton molecular growth but generates C4H4 isomers methylenecyclopropene, vinylacetylene, and 1,2,3-butatriene and smaller C2 and C3 hydrocarbons such as methyl, ethyl, and propargyl radicals, ethylene, and cyclopropenylidene.
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Affiliation(s)
- Anatoliy A Nikolayev
- Lebedev Physical Institute, Samara 443011, Russian Federation.,Samara National Research University, Samara 443086, Russian Federation
| | - Valeriy N Azyazov
- Lebedev Physical Institute, Samara 443011, Russian Federation.,Samara National Research University, Samara 443086, Russian Federation
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Alexander M Mebel
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
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6
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Conrad AR, Hansen N, Jasper AW, Thomason NK, Hidaldo-Rodrigues L, Treshock SP, Popolan-Vaida DM. Identification of the acetaldehyde oxide Criegee intermediate reaction network in the ozone-assisted low-temperature oxidation of trans-2-butene. Phys Chem Chem Phys 2021; 23:23554-23566. [PMID: 34651147 DOI: 10.1039/d1cp03126k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Uni- and bi-molecular reactions involving Criegee intermediates (CIs) have been the focus of many studies due to the role these molecules play in atmospheric chemistry. The reactivity of CIs is known to strongly depend on their structure. The reaction network of the second simplest CI, acetaldehyde oxide (CH3CHOO), is investigated in this work in an atmospheric pressure jet-stirred reactor (JSR) during the ozonolysis of trans-2-butene to explore the kinetic pathways relevant to atmospheric chemistry and low-temperature combustion. The mole fraction profiles of reactants, intermediates, and final products are determined by means of molecular-beam mass spectrometry in conjunction with single-photon ionization employing tunable synchrotron-generated vacuum ultraviolet radiation. A network of CI reactions is identified in the temperature region below 600 K, characterized by CI addition to trans-2-butene, water, formaldehyde, formic acid, and methanol. No sequential additions of the CH3CHOO CI are observed, in contrast with the reactivity of the simplest CI (H2COO) and the earlier observation of an extensive reaction network with up to four H2COO sequential additions (Phys. Chem. Chem. Phys., 2019, 21, 7341-7357). Experimental photoionization efficiency scans recorded at 300 K and 425 K and ab initio threshold energy calculations lead to the identification and quantification of previously elusive intermediates, such as ketohydroperoxide and hydroperoxide species. Specifically, the C4H8 + O3 adduct is identified as a ketohydroperoxide (KHP, 3-hydroperoxybutan-2-one, CH3C(O)CH(CH3)OOH), while hydroxyacetaldehyde (glycolaldehyde, HCOCH2OH) formation is attributed to unimolecular isomerization of the CIs. Other hydroperoxide species such as methyl hydroperoxide (CH3OOH), ethyl hydroperoxide (C2H5OOH), butyl hydroperoxide (OOH), hydroperoxyl acetaldehyde (HOOCH2CHO), hydroxyethyl hydroperoxide (CH3CH(OH)OOH), but-1-enyl-3-hydroperoxide, and 4-hydroxy-3-methylpentan-2-one (HOCH(CH3)CH(CH3)C(O)CH3) are also identified. Detection of additional oxygenated species such as methanol, ethanol, ketene, and aldehydes suggests multiple active oxidation routes. These results provide additional evidence that CIs are key intermediates of the ozone-unsaturated hydrocarbon reactions providing critical inputs for improved kinetics models.
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Affiliation(s)
- Alan R Conrad
- Department of Chemistry, University of Central Florida, Orlando, FL 32816, USA.
| | - Nils Hansen
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551, USA
| | - Ahren W Jasper
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Natasha K Thomason
- Department of Chemistry, University of Central Florida, Orlando, FL 32816, USA.
| | | | - Sean P Treshock
- Department of Chemistry, University of Central Florida, Orlando, FL 32816, USA.
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7
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Caster KL, Selby TM, Osborn DL, Le Picard SD, Goulay F. Product Detection of the CH(X 2Π) Radical Reaction with Cyclopentadiene: A Novel Route to Benzene. J Phys Chem A 2021; 125:6927-6939. [PMID: 34374546 DOI: 10.1021/acs.jpca.1c03517] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reaction of the methylidyne radical (CH(X2Π)) with cyclopentadiene (c-C5H6) is studied in the gas phase at 4 Torr and 373 K using a multiplexed photoionization mass spectrometer. Under multiple collision conditions, the dominant product channel observed is the formation of C6H6 + H. Fitting the photoionization spectrum using reference spectra allows for isomeric resolution of C6H6 isomers, where benzene is the largest contributor with a relative branching fraction of 90 (±5)%. Several other C6H6 isomers are found to have smaller contributions, including fulvene with a branching fraction of 8 (±5)%. Master Equation calculations for four different entrance channels on the C6H7 potential energy surface are performed to explore the competition between CH cycloaddition to a C═C bond vs CH insertion into C-H bonds of cyclopentadiene. Previous studies on CH addition to unsaturated hydrocarbons show little evidence for the C-H insertion pathway. The present computed branching fractions support benzene as the sole cyclic product from CH cycloaddition, whereas fulvene is the dominant product from two of the three pathways for CH insertion into the C-H bonds of cyclopentadiene. The combination of experiment with Master Equation calculations implies that insertion must account for ∼10 (±5)% of the overall CH + cyclopentadiene mechanism.
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Affiliation(s)
- Kacee L Caster
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Talitha M Selby
- Department of Mathematics and Natural Sciences, University of Wisconsin-Milwaukee, West Bend, Wisconsin 53095, United States
| | - David L Osborn
- Combustion Research Facility, Sandia National Laboratories, Mail Stop 9055, Livermore, California 94551, United States
| | - Sebastien D Le Picard
- IPR (Institut de Physique de Rennes), UMR 6251, Univ Rennes, CNRS, F-35000 Rennes, France
| | - Fabien Goulay
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
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8
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Apicella B, Tregrossi A, Oliano MM, Russo C, Ciajolo A. On-line fast analysis of light hydrocarbons, PAH and radicals by molecular-beam time of flight mass spectrometry. CHEMOSPHERE 2021; 276:130174. [PMID: 33743425 DOI: 10.1016/j.chemosphere.2021.130174] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 02/23/2021] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
Volatile organic compounds (VOC) and polycyclic aromatic hydrocarbons (PAH), emitted in the environment from a wide range of combustion sources, are hazardous to human health and considered important precursors of both primary and secondary particulate pollutants. In the present work, light hydrocarbons up to C9, as main components of combustion-derived VOC, and PAH produced in fuel-rich conditions of premixed ethylene flames were analyzed by implementing a molecular-beam time of flight mass spectrometer (MB-TOFMS), purposely built for on-line fast monitoring of the environmental impact of combustion systems. The reliability of the MB-TOFMS was preliminarily verified on a slightly-sooting flame, comparing the results with those obtained by batch sampling and gas chromatographic techniques. Electron ionization (EI) and multi-photon ionization (MPI) were used as MB-TOFMS sources and tested on combustion gases of a no-sooting premixed ethylene flame where VOC and PAH are present in traces not detectable with batch sampling and conventional analytical techniques. The mass identification accuracy was improved and guaranteed by systematically performing internal mass calibration, exploiting the formation of "in situ" clusters from combustion water in the molecular beam apparatus. Selective and sensitive monitoring of light hydrocarbons and PAH, derived from oxidation and pyrolysis reactions featuring combustion, was shown to be especially effective when using the MB-TOFMS equipped with MPI source. This technique showed to be effective also for the detection of radical species that are important for the risk assessment of aerosol and fundamental understanding of aerosol chemistry at a molecular level.
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Affiliation(s)
- Barbara Apicella
- Istituto di Scienze e Tecnologie per L'Energia e La Mobilità Sostenibili, STEMS-CNR, P.le Tecchio 80, 80125, Napoli, Italy.
| | - Antonio Tregrossi
- Istituto di Scienze e Tecnologie per L'Energia e La Mobilità Sostenibili, STEMS-CNR, P.le Tecchio 80, 80125, Napoli, Italy
| | - Maria Maddalena Oliano
- Istituto di Scienze e Tecnologie per L'Energia e La Mobilità Sostenibili, STEMS-CNR, P.le Tecchio 80, 80125, Napoli, Italy
| | - Carmela Russo
- Istituto di Scienze e Tecnologie per L'Energia e La Mobilità Sostenibili, STEMS-CNR, P.le Tecchio 80, 80125, Napoli, Italy
| | - Anna Ciajolo
- Istituto di Scienze e Tecnologie per L'Energia e La Mobilità Sostenibili, STEMS-CNR, P.le Tecchio 80, 80125, Napoli, Italy
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9
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Hu Y, Liu C, Xu Y, Yang J, Pan Y. Identification of Isobars and Isomers in Cigarette Sidestream Smoke in Real Time by Synchrotron Radiation Photoionization Mass Spectrometry and Multiple Linear Regression. Anal Chem 2021; 93:5718-5726. [PMID: 33797228 DOI: 10.1021/acs.analchem.0c04781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Direct analysis of chemical components in fresh cigarette smoke in real time is a challenging task. In this work, by using a novel continuous cigarette-pushing and smoke-introducing setup combined with synchrotron radiation photoionization mass spectrometry (SR-PIMS), the photoionization mass spectra of fresh gaseous cigarette sidestream smoke (SSS) from the combustion of solid tobacco could be recorded in real time, and the photoionization efficiency (PIE) curves of each mass peak could be obtained for the first time. Hence, lots of well-known chemical components and even isomers could be identified by their discriminated onsets or PIE curve simulation. Moreover, diimine, 2H-azirine, and sulfur monoxide, which have never been reported in cigarette smoke, were observed in cigarette SSS, and even two intermediates, ethenol and propen-2-ol, anticipated to exist were actually observed and distinguished. To increase the qualification accuracy, a new simulation method based on multiple linear regression (MLR) was developed and applied for the PIE curve simulation, where qualification mistakes caused by subjective judgements could be eliminated as far as possible.
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Affiliation(s)
- Yonghua Hu
- Center of Technology, China Tobacco Anhui Industrial Co, Ltd, Hefei, Anhui 230088, P. R. China
| | - Chengyuan Liu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
| | - Yingbo Xu
- Center of Technology, China Tobacco Anhui Industrial Co, Ltd, Hefei, Anhui 230088, P. R. China
| | - Jiuzhong Yang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
| | - Yang Pan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
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10
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He C, Nikolayev AA, Zhao L, Thomas AM, Doddipatla S, Galimova GR, Azyazov VN, Mebel AM, Kaiser RI. Gas-Phase Formation of C 5H 6 Isomers via the Crossed Molecular Beam Reaction of the Methylidyne Radical (CH; X 2Π) with 1,2-Butadiene (CH 3CHCCH 2; X 1A'). J Phys Chem A 2021; 125:126-138. [PMID: 33397109 DOI: 10.1021/acs.jpca.0c08731] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The bimolecular gas-phase reaction of the methylidyne radical (CH; X2Π) with 1,2-butadiene (CH2CCHCH3; X1A') was investigated at a collision energy of 20.6 kJ mol-1 under single collision conditions. Combining our laboratory data with high-level electronic structure calculations, we reveal that this bimolecular reaction proceeds through the barrierless addition of the methylidyne radical to the carbon-carbon double bonds of 1,2-butadiene leading to doublet C5H7 intermediates. These collision adducts undergo a nonstatistical unimolecular decomposition through atomic hydrogen elimination to at least the cyclic 1-vinyl-cyclopropene (p5/p26), 1-methyl-3-methylenecyclopropene (p28), and 1,2-bis(methylene)cyclopropane (p29) in overall exoergic reactions. The barrierless nature of this bimolecular reaction suggests that these cyclic C5H6 isomers might be viable targets to be searched for in cold molecular clouds like TMC-1.
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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
| | - Srinivas Doddipatla
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Galiya R Galimova
- Samara National Research University, Samara 443086, Russian Federation.,Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Valeriy N Azyazov
- Samara National Research University, Samara 443086, Russian Federation.,Lebedev Physical Institute, Samara 443011, Russian Federation
| | - 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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Grimm S, Baik SJ, Hemberger P, Bodi A, Kempf AM, Kasper T, Atakan B. Gas-phase aluminium acetylacetonate decomposition: revision of the current mechanism by VUV synchrotron radiation. Phys Chem Chem Phys 2021; 23:15059-15075. [PMID: 34231583 DOI: 10.1039/d1cp00720c] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Although aluminium acetylacetonate, Al(C5H7O2)3, is a common precursor for chemical vapor deposition (CVD) of aluminium oxide, its gas-phase decomposition is not well-known. Here, we studied its thermal decomposition in a microreactor by double imaging photoelectron photoion coincidence spectroscopy (i2PEPICO) between 325 and 1273 K. The reactor flow field was characterized by CFD. Quantum chemical calculations were used for the assignment of certain species. The dissociative ionization of the room temperature precursor molecule starts at a photon energy of 8.5 eV by the rupture of the bond to an acetylacetonate ligand leading to the formation of the Al(C5H7O2)2+ ion. In pyrolysis experiments, up to 49 species were detected and identified in the gas-phase, including reactive intermediates and isomeric/isobaric hydrocarbons, oxygenated species as well as aluminium containing molecules. We detected aluminium bis(diketo)acetylacetonate-H, Al(C5H7O2)C5H6O2, at m/z 224 together with acetylacetone (C5H8O2) as the major initial products formed at temperatures above 600 K. A second decomposition channel affords Al(OH)2(C5H7O2) along with the formation of a substituted pentalene ring species (C10H12O2) as assigned by Franck-Condon simulations and quantum chemical calculations. Acetylallene (C5H6O), acetone (C3H6O) and ketene (C2H2O) were major secondary decomposition products, formed upon decomposition of the primary products. Three gas-phase aromatic hydrocarbons were also detected and partially assigned for the first time: m/z 210, m/z 186 (C14H18 or C12H10O2) and m/z 146 (C11H14 or C9H6O2) and their formation mechanism is discussed. Finally, Arrhenius parameters are presented on the gas-phase decomposition kinetics of Al(C5H7O2)3, aided by numerical simulation of the flow field.
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Affiliation(s)
- Sebastian Grimm
- University of Duisburg-Essen, Institute of Combustion and Gas Dynamics, Chair of Thermodynamics, Duisburg 47057, Germany. and Center for NanoIntegration Duisburg-Essen (CENIDE), Duisburg 47057, Germany
| | - Seung-Jin Baik
- Center for NanoIntegration Duisburg-Essen (CENIDE), Duisburg 47057, Germany and University of Duisburg-Essen, Institute of Combustion and Gas Dynamics, Chair of Fluid Dynamics, Duisburg 47057, Germany
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - Andreas M Kempf
- Center for NanoIntegration Duisburg-Essen (CENIDE), Duisburg 47057, Germany and University of Duisburg-Essen, Institute of Combustion and Gas Dynamics, Chair of Fluid Dynamics, Duisburg 47057, Germany
| | - Tina Kasper
- Center for NanoIntegration Duisburg-Essen (CENIDE), Duisburg 47057, Germany and University of Duisburg-Essen, Institute of Combustion and Gas Dynamics, Chair of Mass Spectrometry of Reactive Fluids, Duisburg 47057, Germany
| | - Burak Atakan
- University of Duisburg-Essen, Institute of Combustion and Gas Dynamics, Chair of Thermodynamics, Duisburg 47057, Germany. and Center for NanoIntegration Duisburg-Essen (CENIDE), Duisburg 47057, Germany
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12
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Krasnoukhov VS, Zagidullin MV, Zavershinskiy IP, Mebel AM. Formation of Phenanthrene via Recombination of Indenyl and Cyclopentadienyl Radicals: A Theoretical Study. J Phys Chem A 2020; 124:9933-9941. [PMID: 33205982 DOI: 10.1021/acs.jpca.0c09091] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This work presents quantum chemical G3(MP2,CC)//B2PLYPD3/6-311G(d,p) calculations of the potential energy surface for the indenyl (C9H7) + cyclopentadienyl (C5H5) reaction followed by unimolecular decomposition of the C14H11 radicals formed as the primary products, as well as the Rice-Ramsperger-Kassel-Marcus master equation (RRKM-ME) calculations to predict temperature- and pressure-dependent reaction rate constants and product branching ratios. The reaction begins with the barrierless recombination of indenyl and cyclopentadienyl forming a C14H12 molecule with a new C-C bond connecting two five-membered rings, which subsequently dissociates to C14H11 radicals by H losses. The primary products of the C9H7 + C5H5 → C14H11 + H reaction can directly decompose by another H loss to benzofulvalene, and this pathway is most favorable in terms of the entropy factor and hence is preferable at higher temperatures. Otherwise, the initial C14H11 isomers can undergo significant structural rearrangements before eliminating an H atom and producing phenanthrene, anthracene, or benzoazulenes, among which the formation of phenanthrene via the "spiran" pathway is clearly preferred. The calculated barriers along the computed favorable dissociation pathways are relatively low, in the ∼30-40 kcal/mol range, making the C14H11 radicals unstable at temperatures above 1000-1250 K at 1 atm. The results of RRKM-ME calculations show that, under typical combustion conditions, the decomposition of the C14H11 radicals predominantly leads to benzofulvalene. However, the latter can be rapidly converted to phenanthrene via H-assisted isomerization with the rate constant for the benzofulvalene + H → phenanthrene + H reaction being close to 10-11 cm3 molecule-1 s-1 at 1000-1500 K and 1 atm. The results provide further support for the hypothesis that recombination of two π radicals containing five-membered rings can lead to a growth of PAH with the formation of two fused six-membered rings, but the reaction mechanism may not be direct and is likely to involve two consecutive H atom losses leading to a fulvalene-like product, with subsequent H-assisted isomerization of the latter to a benzenoid PAH.
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Affiliation(s)
| | | | | | - Alexander M Mebel
- Samara National Research University, Samara 443086, Russian Federation.,Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
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13
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He C, Zhao L, Doddipatla S, Thomas AM, Nikolayev AA, Galimova GR, Azyazov VN, Mebel AM, Kaiser RI. Gas-Phase Synthesis of 3-Vinylcyclopropene via the Crossed Beam Reaction of the Methylidyne Radical (CH; X 2 Π) with 1,3-Butadiene (CH 2 CHCHCH 2 ; X 1 A g ). Chemphyschem 2020; 21:1295-1309. [PMID: 32291897 DOI: 10.1002/cphc.202000183] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/12/2020] [Indexed: 12/18/2022]
Abstract
The crossed molecular beam reactions of the methylidyne radical (CH; X2 Π) with 1,3-butadiene (CH2 CHCHCH2 ; X1 Ag ) along with their (partially) deuterated counterparts were performed at collision energies of 20.8 kJ mol-1 under single collision conditions. Combining our laboratory data with ab initio calculations, we reveal that the methylidyne radical may add barrierlessly to the terminal carbon atom and/or carbon-carbon double bond of 1,3-butadiene, leading to doublet C5 H7 intermediates with life times longer than the rotation periods. These collision complexes undergo non-statistical unimolecular decomposition through hydrogen atom emission yielding the cyclic cis- and trans-3-vinyl-cyclopropene products with reaction exoergicities of 119±42 kJ mol-1 . Since this reaction is barrierless, exoergic, and all transition states are located below the energy of the separated reactants, these cyclic C5 H6 products are predicted to be accessed even in low-temperature environments, such as in hydrocarbon-rich atmospheres of planets and 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, USA
| | - Long Zhao
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii, 96822, USA
| | - Srinivas Doddipatla
- 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
- Samara National Research University, Samara, 443086, Russian Federation.,Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, 33199, USA
| | - Valeriy N Azyazov
- Samara National Research University, Samara, 443086, Russian Federation.,Lebedev Physical Institute, Samara, 443011, Russian Federation
| | - Alexander M Mebel
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, 33199, USA
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii, 96822, USA
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14
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Reilly NJ, Kokkin DL, Ward ML, Flores J, Ross SD, McCaslin LM, Stanton JF. Gas-Phase Optical Detection of 3-Ethynylcyclopentenyl: A Resonance-Stabilized C7H7 Radical with an Embedded 1-Vinylpropargyl Chromophore. J Am Chem Soc 2020; 142:10400-10411. [DOI: 10.1021/jacs.0c01579] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Neil J. Reilly
- Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston Massachusetts 02125, United States
| | - Damian L. Kokkin
- Department of Chemistry, Marquette University, P.O. Box 1881 Milwaukee, Wisconsin 53201, United States
| | - Meredith L. Ward
- Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston Massachusetts 02125, United States
| | - Jonathan Flores
- Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston Massachusetts 02125, United States
| | - Sederra D. Ross
- Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston Massachusetts 02125, United States
| | - Laura M. McCaslin
- Institute of Chemistry and the Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem 9190401, Israel
| | - John F. Stanton
- Quantum Theory Project, Departments of Chemistry and Physics, The University of Florida, Gainesville Florida 32611, United States
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15
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Thirumoorthy K, Cooksy AL, Thimmakondu VS. Si 2C 5H 2 isomers - search algorithms versus chemical intuition. Phys Chem Chem Phys 2020; 22:5865-5872. [PMID: 32108184 DOI: 10.1039/c9cp06145b] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The pros and cons of using search algorithms alone in identifying new geometries have been discussed by using the Si2C5H2 elemental composition as an example. Within 30 kcal mol-1 at the CCSD(T)/def2-TZVP//PBE0/def2-TZVP level of theory, the coalescence kick and cuckoo methods postulate merely four isomers (1, 3, 6, and 7) for Si2C5H2 (O. Yañez et. al., Chem. Commun., 2017, 53, 12112). On the contrary, chemical intuition yields fourteen (2, 4, 5, and 8-18) new isomers within the same energy range at the B3LYP/6-311++G(2d,2p) level of theory. Based on the relative energies of the first eleven isomers of Si2C5H2 (1, C2v, 0.00; 2, Cs, 21.39; 3, Cs, 21.95; 4, Cs, 22.76; 5, Cs, 24.74; 6, Cs, 25.34; 7, Cs, 25.64; 8, Cs, 25.79; 9, Cs, 27.20; 10, C2v, 28.59; and 11, C2v, 29.16 kcal mol-1) calculated at the CCSD(T)/cc-pVTZ level of theory, it is evident that the search algorithms had missed at least seven isomers in the same energy range. The relative energy gaps of isomers 12-18 fall in the range of 30-40 kcal mol-1 at the latter level of theory. Consequentially, this scenario triggers a speculation going forward with search algorithms alone in the search of all new isomers. While one cannot underestimate the power of these algorithms, the role of chemical intuition may not be completely neglected. Retrospectively, the fourteen new isomers found by chemical intuition may help in writing better search algorithms. All eighteen isomers - including the most stable isomer with a planar tetracoordinate carbon atom 1- remain elusive in the laboratory to date. Thus, structural and spectroscopic parameters have been presented here, which may possibly aid the future experimental studies.
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Affiliation(s)
- Krishnan Thirumoorthy
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore - 632 014, Tamil Nadu, India
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16
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Job N, Karton A, Thirumoorthy K, Cooksy AL, Thimmakondu VS. Theoretical Studies of SiC 4H 2 Isomers Delineate Three Low-Lying Silylidenes Are Missing in the Laboratory. J Phys Chem A 2020; 124:987-1002. [PMID: 31904236 DOI: 10.1021/acs.jpca.9b11742] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Eleven isomers of SiC4H2 lying within 50 kcal mol-1 have been theoretically investigated using density functional theory and high-level coupled-cluster methods. Among them, four isomers, 1-ethynyl-3-silacycloprop-1(2)-en-3-ylidene (1), diethynylsilylidene (2), 1-sila-1,2,3,4-pentatetraenylidene (4), and 1,3-butadiynylsilylidene (5), have already been identified in the laboratory. The current investigation reports three low-lying (<1 eV) silylidenes [2-methylenesilabicyclo[1.1.0]but-1(3)-en-4-ylidene (3), 4-sila-2-methylenebicyclo[1.1.0]but-1(3)-en-4-ylidene (6), and 3-ethynyl-1-silapropadienylidene (7)] and three high-lying (>1 eV) silylidenes [2-sila-(didehydrovinylidene)cyclopropene (8), an isomer with a planar tetracoordinate carbon (ptC) atom (10), and 1-ethynyl-1-silapropadienylidene (11)], which remain elusive in the laboratory to date. Isomer 9 also contains a ptC atom, which turned out to be a transition state at all levels. Though all isomers are polar (μ ≠ 0), rotational spectrum is available only for 4. Using matrix isolation, three isomers (1, 2, and 5) have been trapped in the laboratory at 10 K. Considering the astrochemical relevance of silicon-carbide clusters in the interstellar medium, the current theoretical data demand new molecular spectroscopic studies on SiC4H2. Surprisingly, unlike the isovalent C5H2 isomers, where the bent carbenes are yet to be identified in the laboratory, the bent silylidenes (2 and 5) have been trapped in the case of SiC4H2. In both the cases, molecules with transannular C-C and/or Si-C bonds remain elusive, though they lie in the low-lying region. Using suitable precursors, whether these peculiar geometries (especially 3 and 6) would be identified or not in the laboratory needs to be addressed by molecular spectroscopists. The present investigation documents structural and spectroscopic information of SiC4H2 isomers, which may compliment future molecular spectroscopic observations including radioastronomical searches.
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Affiliation(s)
- Nisha Job
- Department of Chemistry, School of Advanced Sciences , Vellore Institute of Technology , Vellore 632014 , Tamil Nadu , India
| | - Amir Karton
- School of Molecular Sciences , The University of Western Australia , Perth , Western Australia 6009 , Australia
| | - Krishnan Thirumoorthy
- Department of Chemistry, School of Advanced Sciences , Vellore Institute of Technology , Vellore 632014 , Tamil Nadu , India
| | - Andrew L Cooksy
- Department of Chemistry and Biochemistry , San Diego State University , San Diego , California 92182-1030 , United States
| | - Venkatesan S Thimmakondu
- Department of Chemistry and Biochemistry , San Diego State University , San Diego , California 92182-1030 , United States
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17
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Thirumoorthy K, Viji M, Pandey AP, Netke TG, Sekar B, Yadav G, Deshpande S, Thimmakondu VS. Many unknowns below or close to the experimentally known cumulene carbene – A case study of C9H2 isomers. Chem Phys 2019. [DOI: 10.1016/j.chemphys.2019.110496] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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18
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Li X, Gao Y, Zuo C, Zheng S, Xu F, Sun Y, Zhang Q. The Gas-Phase Formation Mechanism of Dibenzofuran (DBF), Dibenzothiophene (DBT), and Carbazole (CA) from Benzofuran (BF), Benzothiophene (BT), and Indole (IN) with Cyclopentadienyl Radical. Int J Mol Sci 2019; 20:E5420. [PMID: 31683506 PMCID: PMC6861977 DOI: 10.3390/ijms20215420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 10/28/2019] [Accepted: 10/28/2019] [Indexed: 11/16/2022] Open
Abstract
Benzofuran (BF), benzothiophene (BT), indole (IN), dibenzofuran (DBF), dibenzothiophene (DBT), and carbazole (CA) are typical heterocyclic aromatic compounds (NSO-HETs), which can coexist with polycyclic aromatic hydrocarbons (PAHs) in combustion and pyrolysis conditions. In this work, quantum chemical calculations were carried out to investigate the formation of DBF, DBT, and CA from the reactions of BF, BT, and IN with a cyclopentadienyl radical (CPDyl) by using the hybrid density functional theory (DFT) at the MPWB1K/6-311+G(3df,2p)//MPWB1K/6-31+G(d,p) level. The rate constants of crucial elementary steps were deduced over 600-1200 K, using canonical variational transition state theory with a small-curvature tunneling contribution (CVT/SCT). This paper showed that the production of DBF, DBT, and CA from the reactions of BF, BT, and IN with CPDyl involved six elementary steps: the addition reaction, ring closure, the first H shift, C-C cleavage, the second H shift, and elimination of CH3 or H. The cleavage of the C-C bond was regarded as the rate-determining step for each pathway due to the extremely high barrier. The 1-methyl substituted products were more easily formed than the 4-methyl substituted products. The main products were DBF and 1-methyl-DBF, DBT and 1-methyl-DBT, and CA and 1-methyl-CA for reactions of BF, BT, and IN with CPDyl, respectively. The ranking of DBF, DBT, and CA formation potential was as follows: DBT and methyl-DBT formation > DBF and methyl-DBF formation > CA, and methyl-CA formation. Comparison with the reaction of naphthalene with CPDyl indicated that the reactions of CPDyl attacking a benzene ring and a furan/thiophene/pyrrole ring could be inferred to be comparable under high temperature conditions.
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Affiliation(s)
- Xuan Li
- Environment Research Institute, Shandong University, Qingdao 266237, China.
| | - Yixiang Gao
- Environment Research Institute, Shandong University, Qingdao 266237, China.
| | - Chenpeng Zuo
- Environment Research Institute, Shandong University, Qingdao 266237, China.
- Shenzhen Research Institute, Shandong University, Shenzhen 518057, China.
| | - Siyuan Zheng
- Environment Research Institute, Shandong University, Qingdao 266237, China.
| | - Fei Xu
- Environment Research Institute, Shandong University, Qingdao 266237, China.
- Shenzhen Research Institute, Shandong University, Shenzhen 518057, China.
| | - Yanhui Sun
- College of Environment and Safety Engineering, Qingdao University of Science & Technology, Qingdao 266042, China.
| | - Qingzhu Zhang
- Environment Research Institute, Shandong University, Qingdao 266237, China.
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19
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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: 7] [Impact Index Per Article: 1.4] [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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20
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Hansen N, Moshammer K, Jasper AW. Isomer-Selective Detection of Keto-Hydroperoxides in the Low-Temperature Oxidation of Tetrahydrofuran. J Phys Chem A 2019; 123:8274-8284. [PMID: 31483667 DOI: 10.1021/acs.jpca.9b07017] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Keto-hydroperoxides (KHPs) are reactive, partially oxidized intermediates that play a central role in chain-branching reactions during the gas-phase low-temperature oxidation of hydrocarbons and oxygenated species. Although multiple isomeric forms of the KHP intermediate are possible in complex oxidation environments when multiple reactant radicals exist that contain nonequivalent O2 addition sites, isomer-resolved data of KHPs have not been reported. In this work, we provide partially isomer-resolved detection and quantification of the KHPs that form during the low-temperature oxidation of tetrahydrofuran (THF, cycl.-O-CH2CH2CH2CH2-). We describe how these short-lived KHPs were detected, identified, and quantified using integrated experimental and theoretical approaches. The experimental approaches were based on direct molecular-beam sampling from a jet-stirred reactor operated at near-atmospheric pressure and at temperatures between 500 and 700 K, followed by mass spectrometry with single-photon ionization via tunable synchrotron-generated vacuum-ultraviolet radiation, and the identification of fragmentation patterns. The interpretation of the experiments was guided by theoretical calculations of ionization thresholds, fragment appearance energies, and photoionization cross sections. On the basis of the experimentally observed and theoretically calculated ionization and fragment appearance energies, KHP isomers could be distinguished as originating from H-abstraction reactions from either the α-C adjacent to the O atom or the β-C atoms. Temperature-dependent concentration profiles of the partially resolved isomeric KHP intermediates were determined in the range of 500-700 K, and the results indicate that the observed KHP isomers are formed overwhelmingly (∼99%) from the α-C THF radical. Comparisons of the partially isomer-resolved quantification of the KHPs to up-to-date kinetic modeling results reveal new opportunities for the development of a next-generation THF oxidation mechanism.
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Affiliation(s)
- Nils Hansen
- Combustion Research Facility , Sandia National Laboratories , Livermore , California 94551 , United States
| | - Kai Moshammer
- Physikalisch-Technische Bundesanstalt , Bundesallee 100 , 38116 Braunschweig , Germany
| | - Ahren W Jasper
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Lemont , Illinois 60439 , United States
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21
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Thimmakondu VS, Ulusoy I, Wilson AK, Karton A. Theoretical Studies of Two Key Low-Lying Carbenes of C 5H 2 Missing in the Laboratory. J Phys Chem A 2019; 123:6618-6627. [PMID: 31269401 DOI: 10.1021/acs.jpca.9b06036] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The equilibrium geometries and spectroscopic properties of two key singlet carbenes, buta-1,3-diynylcarbene (6) and 2-methylenebicyclo[1.1.0]but-1(3)-en-4-ylidene (9), which have not been experimentally observed to date, are investigated using high-level coupled-cluster (CC) methods. The current theoretical study necessitates new experimental data on C5H2 isomers considering the relevance of these molecules to interstellar chemistry. Bent-pentadiynylidene (4) has been missing in the laboratory and the prime focus of our earlier theoretical work. The present theoretical study indicates that isomers 6 and 9 are also viable experimental targets. Apart from ethynylcyclopropenylidene (2), pentatetraenylidene (3), ethynylpropadienylidene (5), and 3-(didehydrovinylidene)cyclopropene (8), which are identified by Fourier transform microwave spectroscopy, the dipole moments of elusive 4, 6, and 9 are also nonzero (μ ≠ 0). The relative energies of these isomers, calculated at the CCSDT(Q)/CBS level of theory, with respect to linear triplet pentadiynylidene (1) reveal that they all lie within 25.1 kcal mol-1. Therefore, geometric, energetic, aromatic, and spectroscopic parameters are reported here, which may assist the efforts of molecular spectroscopists in the future. Anharmonic vibrational calculations on isomers 6 and 9 indicate that the former is loosely bound and would be challenging to be detected experimentally. Among the undetected carbenes, 9 may be considered as a potential target molecule considering its higher polarity and aromatic nature.
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Affiliation(s)
- Venkatesan S Thimmakondu
- Department of Chemistry and Biochemistry , San Diego State University , San Diego , California 92182-1030 , United States
| | - Inga Ulusoy
- Theoretical Chemistry, Institute of Physical Chemistry , Heidelberg University , Im Neuenheimer Feld 229 , 69120 Heidelberg , Germany.,Department of Chemistry , Michigan State University , East Lansing , Michigan 48824-1322 , United States
| | - Angela K Wilson
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824-1322 , United States
| | - Amir Karton
- School of Molecular Sciences , The University of Western Australia , Perth , Western Australia 6009 , Australia
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22
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Jin H, Yang J, Xing L, Hao J, Zhang Y, Cao C, Pan Y, Farooq A. An experimental study of indene pyrolysis with synchrotron vacuum ultraviolet photoionization mass spectrometry. Phys Chem Chem Phys 2019; 21:5510-5520. [PMID: 30785151 DOI: 10.1039/c8cp07285j] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Pyrolytic kinetics of indene was studied in a flow reactor at 30 and 760 Torr. Indene and its decomposition products, as well as polycyclic aromatic hydrocarbons (PAHs), were measured with synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS). Five literature models were selected to reproduce the experimental data and analyze the reaction kinetics of indene. The experimental and predicted results illustrate that an indenyl radical is the dominant decomposition intermediate and also the main contributor to the further growth of aromatic rings in the pyrolysis of indene. The indene consumption process needs further precise characterization, especially the subsequent dissociation reactions of indanyl and indenyl radicals. A self-recombination reaction of the indenyl radical and the combination reactions between indenyl and other radicals are found to be necessary for the efficient formation of large PAHs. The absence of these pathways leads to the underprediction of experimental measurements. In contrast, literature models adopting indenyl global reactions for PAH formation generally overestimate the system reactivity. Proper radical combination pathways proposed in a future model should consider not only the PAH formation efficiency but also its impact on system reactivity.
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Affiliation(s)
- Hanfeng Jin
- Clean Combustion Research Centre, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
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23
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Rousso AC, Hansen N, Jasper AW, Ju Y. Identification of the Criegee intermediate reaction network in ethylene ozonolysis: impact on energy conversion strategies and atmospheric chemistry. Phys Chem Chem Phys 2019; 21:7341-7357. [DOI: 10.1039/c9cp00473d] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction network of the simplest Criegee intermediate (CI) CH2OO has been studied experimentally during the ozonolysis of ethylene.
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Affiliation(s)
- Aric C. Rousso
- Department of Mechanical and Aerospace Engineering
- Princeton University
- USA
| | - Nils Hansen
- Combustion Research Facility
- Sandia National Laboratories
- Livermore
- USA
| | - Ahren W. Jasper
- Chemical Sciences and Engineering Division
- Argonne National Laboratory
- Lemont
- USA
| | - Yiguang Ju
- Department of Mechanical and Aerospace Engineering
- Princeton University
- USA
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24
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Knyazev VD. Kinetics of the Reaction of the Cyclopentadienyl Radical with Nitrogen Dioxide. J Phys Chem A 2018; 122:6978-6984. [PMID: 30092642 DOI: 10.1021/acs.jpca.8b05854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The kinetics of the reaction of the cyclopentadienyl radical (c-C5H5) with nitrogen dioxide (NO2) was studied by laser photolysis/photoionization mass spectroscopy. Overall rate constants were obtained in direct real-time experiments in the temperature region 305-800 K and at bath gas densities of (3.0-12.0) × 1016 molecules cm-3. The overall rate constant is independent of temperature between 300 and 400 K but decreases by a factor of approximately 7 above 400 K, without any discernible pressure dependence. A potential energy surface study of the reaction was performed, and an RRKM/master equation model was created. The reaction proceeds via initial addition to one of the two types of atoms of the NO2 molecule (nitrogen or oxygen). The N-bonded adduct can isomerize and decompose back to the reactants; this channel is significantly affected by falloff above 400 K and, although dominant at room temperature, becomes negligible at 600 K and above. The O-bonded adduct undergoes chemically activated isomerizations and decomposition, with a minor contribution from stabilization at low temperatures; this channel dominates at high temperatures and is effectively pressure-independent. The model provides a quantitative explanation for the observed temperature dependence of the rate constant.
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Affiliation(s)
- Vadim D Knyazev
- Research Center for Chemical Kinetics Department of Chemistry , The Catholic University of America , Washington , D.C. 20064 , United States
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25
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Moreno-Armenta MG, Pearce HR, Winter P, Cooksy AL. Computational search for metastable high-spin C5Hn (n = 4, 5, 6) species. COMPUT THEOR CHEM 2018. [DOI: 10.1016/j.comptc.2018.07.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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26
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Carrasco E, Meloni G. Study of Methylidyne Radical (CH and CD) Reaction with 2,5-Dimethylfuran Using Multiplexed Synchrotron Photoionization Mass Spectrometry. J Phys Chem A 2018; 122:6118-6133. [DOI: 10.1021/acs.jpca.8b04140] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Erica Carrasco
- Department of Chemistry, University of San Francisco, San Francisco, California 94117, United States
| | - Giovanni Meloni
- Department of Physical and Chemical Sciences, Università degli Studi de L’Aquila, L’Aquila, Italy
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27
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Muz İ, Kurban M. Ab initio study of structural and electronic properties of SinC5-nH8 (n = 0–5) series: Probing the 2D to 3D structural transition. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2018.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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28
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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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29
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Shapero M, Ramphal IA, Neumark DM. Photodissociation of the Cyclopentadienyl Radical at 248 nm. J Phys Chem A 2018; 122:4265-4272. [DOI: 10.1021/acs.jpca.7b11837] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mark Shapero
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Isaac A. Ramphal
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Daniel M. Neumark
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
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30
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Wei M, Zhang T, Chen X, Yan F, Guo G, Zhang D. Formation of bicyclic polycyclic aromatic hydrocarbons (PAHs) from the reaction of a phenyl radical with cis-3-penten-1-yne. RSC Adv 2018; 8:13226-13236. [PMID: 35542549 PMCID: PMC9079691 DOI: 10.1039/c8ra01449c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 03/21/2018] [Indexed: 11/21/2022] Open
Abstract
The formation of PAHs within 4-, 5-, 6- and 7-membered rings on the C6H5 + C5H6 potential energy surface.
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Affiliation(s)
- Mingrui Wei
- Hubei Key Laboratory of Advanced Technology for Automotive Components
- Hubei Collaborative Innovation Center for Automotive Components Technology
- Wuhan University of Technology
- Wuhan 430070
- PR China
| | - Tingting Zhang
- Hubei Key Laboratory of Advanced Technology for Automotive Components
- Hubei Collaborative Innovation Center for Automotive Components Technology
- Wuhan University of Technology
- Wuhan 430070
- PR China
| | - Xianfeng Chen
- School of Resources and Environmental Engineering
- Wuhan University of Technology
- Wuhan 430070
- China
| | - Fuwu Yan
- Hubei Key Laboratory of Advanced Technology for Automotive Components
- Hubei Collaborative Innovation Center for Automotive Components Technology
- Wuhan University of Technology
- Wuhan 430070
- PR China
| | - Guanlun Guo
- Hubei Key Laboratory of Advanced Technology for Automotive Components
- Hubei Collaborative Innovation Center for Automotive Components Technology
- Wuhan University of Technology
- Wuhan 430070
- PR China
| | - Dongju Zhang
- Key Lab of Colloid and Interface Chemistry
- Ministry of Education
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan 250000
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31
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Carrasco E, Smith KJ, Meloni G. Synchrotron Photoionization Study of Furan and 2-Methylfuran Reactions with Methylidyne Radical (CH) at 298 K. J Phys Chem A 2017; 122:280-291. [DOI: 10.1021/acs.jpca.7b10382] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Erica Carrasco
- Department of Chemistry, University of San Francisco, San
Francisco, California 94117, United States
| | - Kenneth J. Smith
- Department of Chemistry, University of San Francisco, San
Francisco, California 94117, United States
| | - Giovanni Meloni
- Department of Chemistry, University of San Francisco, San
Francisco, California 94117, United States
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32
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Zhu L, Shi X, Sun Y, Zhang Q, Wang W. The growth mechanism of polycyclic aromatic hydrocarbons from the reactions of anthracene and phenanthrene with cyclopentadienyl and indenyl. CHEMOSPHERE 2017; 189:265-276. [PMID: 28942252 DOI: 10.1016/j.chemosphere.2017.09.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Revised: 08/30/2017] [Accepted: 09/01/2017] [Indexed: 06/07/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are highly toxic, mutagenic and/or carcinogenic to humans. To reduce the emission of PAHs, it's significant and indispensable to explore the PAH formation mechanism. In the present work, the growth mechanism of PAHs from the reactions of anthracene and phenanthrene with cyclopentadienyl and indenyl radicals was investigated with the aid of high-accuracy quantum chemistry calculation. The rate constants of key elementary steps were calculated by meaning of the canonical variation transition-state (CVT) theory with the small curvature tunneling (SCT) correction over the temperature range of 400-1400 K. The mechanism of the PAH formation involves in six elementary steps, addition reaction, ring closure, intramolecular H-shift, cleavage of CC bond, intramolecular H-shift and unimolecular elimination of CH3 or H. The cleavage of CC bond is the rate-determining step due to the high barrier. The formation of PAHs from the reactions of anthracene with cyclopentadienyl and indenyl radicals is easier than that from the reactions of phenanthrene.
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Affiliation(s)
- Ledong Zhu
- Environment Research Institute, Shandong University, Jinan, 250100, PR China
| | - Xiangli Shi
- Environment Research Institute, Shandong University, Jinan, 250100, PR China
| | - Yanhui Sun
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China
| | - Qingzhu Zhang
- Environment Research Institute, Shandong University, Jinan, 250100, PR China.
| | - Wenxing Wang
- Environment Research Institute, Shandong University, Jinan, 250100, PR China
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33
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Kondrateva AS, Mishin MV, Alexandrov SE. TOF MS Investigation of Nickel Oxide CVD. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:2352-2360. [PMID: 28801779 DOI: 10.1007/s13361-017-1765-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 07/18/2017] [Accepted: 07/18/2017] [Indexed: 06/07/2023]
Abstract
NiO layers were deposited by metal-organic chemical vapor deposition using bis-(ethylcyclopentadienyl) nickel (EtCp)2Ni and oxygen or ozone. As a continuation of kinetic study of NiO MOCVD the gas-phase, transformations of (EtCp)2Ni were studied in the temperature range of 380-830 K. Time of reactions corresponding to the residence time of the gas stream in hot zone of the reactor was about 0.1 s under conditions studied. The interaction of (EtCp)2Ni with oxygen started at 450 K and its conversion rate reached the maximum at 700 K. The interaction of (EtCp)2Ni with ozone started at 400 K and its conversion rate reached the maximum at 600 K. Transformations of the gas phase with the temperature in the reaction zone were studied, the model reaction schemes illustrating (EtCp)2Ni transformations in the reaction systems containing oxygen and ozone have developed. In the reaction system (EtCp)2Ni-O2-Ar the main gas-phase products at 380-500 K were CO, CO2, HCO, C2H5OH, CpCOOH, and CpO. Formation of the C2H2O, C3H4O, and C5H8O was found at 630-830 K. The same gas-phase species, (C4H3O)2Ni and dialdehydes was formed in the reaction system (EtCp)2Ni-O3-O2-Ar. Graphical Abstract ᅟ.
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Affiliation(s)
- Anastasia S Kondrateva
- Department of Physical Chemistry and Microsystem Technology, Peter the Great Saint Petersburg State Polytechnic University, Polytechnicheskaya str. 29, St. Petersburg, 195251, Russian Federation.
| | - Maxim V Mishin
- Department of Physical Chemistry and Microsystem Technology, Peter the Great Saint Petersburg State Polytechnic University, Polytechnicheskaya str. 29, St. Petersburg, 195251, Russian Federation
| | - Sergey E Alexandrov
- Department of Physical Chemistry and Microsystem Technology, Peter the Great Saint Petersburg State Polytechnic University, Polytechnicheskaya str. 29, St. Petersburg, 195251, Russian Federation
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34
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Isomer Identification in Flames with Double-Imaging Photoelectron/Photoion Coincidence Spectroscopy (i2PEPICO) using Measured and Calculated Reference Photoelectron Spectra. ACTA ACUST UNITED AC 2017. [DOI: 10.1515/zpch-2017-1009] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Double-imaging photoelectron/photoion coincidence (i2PEPICO) spectroscopy using a multiplexing, time-efficient, fixed-photon-energy approach offers important opportunities of gas-phase analysis. Building on successful applications in combustion systems that have demonstrated the discriminative power of this technique, we attempt here to push the limits of its application further to more chemically complex combustion examples. The present investigation is devoted to identifying and potentially quantifying compounds featuring five heavy atoms in laminar, premixed low-pressure flames of hydrocarbon and oxygenated fuels and their mixtures. In these combustion examples from flames of cyclopentene, iso-pentane, iso-pentane blended with dimethyl ether (DME), and diethyl ether (DEE), we focus on the unambiguous assignment and quantitative detection of species with the sum formulae C5H6, C5H7, C5H8, C5H10, and C4H8O in the respective isomer mixtures, attempting to provide answers to specific chemical questions for each of these examples. To analyze the obtained i2PEPICO results from these combustion situations, photoelectron spectra (PES) from pure reference compounds, including several examples previously unavailable in the literature, were recorded with the same experimental setup as used in the flame measurements. In addition, PES of two species where reference spectra have not been obtained, namely 2-methyl-1-butene (C5H10) and the 2-cyclopentenyl radical (C5H7), were calculated on the basis of high-level ab initio calculations and Franck-Condon (FC) simulations. These reference measurements and quantum chemical calculations support the early fuel decomposition scheme in the cyclopentene flame towards 2-cyclopentenyl as the dominant fuel radical as well as the prevalence of branched intermediates in the early fuel destruction reactions in the iso-pentane flame, with only minor influences from DME addition. Furthermore, the presence of ethyl vinyl ether (EVE) in DEE flames that was predicted by a recent DEE combustion mechanism could be confirmed unambiguously. While combustion measurements using i2PEPICO can be readily obtained in isomer-rich situations, we wish to highlight the crucial need for high-quality reference information to assign and evaluate the obtained spectra.
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35
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Oswald T, Gelert T, Lasar C, Schmidtmann M, Klüner T, Beckhaus R. Formation of Binuclear Zigzag Hexapentaene Titanium Complexes via a Titanacumulene [Ti=C=C=CH2
] Intermediate. Angew Chem Int Ed Engl 2017; 56:12297-12301. [DOI: 10.1002/anie.201706674] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 07/26/2017] [Indexed: 11/10/2022]
Affiliation(s)
- Tim Oswald
- Institut für Chemie; Fakultät für Mathematik und Naturwissenschaften, Carl von Ossietzky-Universität Oldenburg; Postfach 2503 26111 Oldenburg Germany
| | - Tina Gelert
- Institut für Chemie; Fakultät für Mathematik und Naturwissenschaften, Carl von Ossietzky-Universität Oldenburg; Postfach 2503 26111 Oldenburg Germany
| | - Christian Lasar
- Institut für Chemie; Fakultät für Mathematik und Naturwissenschaften, Carl von Ossietzky-Universität Oldenburg; Postfach 2503 26111 Oldenburg Germany
| | - Marc Schmidtmann
- Institut für Chemie; Fakultät für Mathematik und Naturwissenschaften, Carl von Ossietzky-Universität Oldenburg; Postfach 2503 26111 Oldenburg Germany
| | - Thorsten Klüner
- Institut für Chemie; Fakultät für Mathematik und Naturwissenschaften, Carl von Ossietzky-Universität Oldenburg; Postfach 2503 26111 Oldenburg Germany
| | - Rüdiger Beckhaus
- Institut für Chemie; Fakultät für Mathematik und Naturwissenschaften, Carl von Ossietzky-Universität Oldenburg; Postfach 2503 26111 Oldenburg Germany
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36
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Oswald T, Gelert T, Lasar C, Schmidtmann M, Klüner T, Beckhaus R. Formation of Binuclear Zigzag Hexapentaene Titanium Complexes via a Titanacumulene [Ti=C=C=CH2
] Intermediate. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201706674] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Tim Oswald
- Institut für Chemie; Fakultät für Mathematik und Naturwissenschaften, Carl von Ossietzky-Universität Oldenburg; Postfach 2503 26111 Oldenburg Germany
| | - Tina Gelert
- Institut für Chemie; Fakultät für Mathematik und Naturwissenschaften, Carl von Ossietzky-Universität Oldenburg; Postfach 2503 26111 Oldenburg Germany
| | - Christian Lasar
- Institut für Chemie; Fakultät für Mathematik und Naturwissenschaften, Carl von Ossietzky-Universität Oldenburg; Postfach 2503 26111 Oldenburg Germany
| | - Marc Schmidtmann
- Institut für Chemie; Fakultät für Mathematik und Naturwissenschaften, Carl von Ossietzky-Universität Oldenburg; Postfach 2503 26111 Oldenburg Germany
| | - Thorsten Klüner
- Institut für Chemie; Fakultät für Mathematik und Naturwissenschaften, Carl von Ossietzky-Universität Oldenburg; Postfach 2503 26111 Oldenburg Germany
| | - Rüdiger Beckhaus
- Institut für Chemie; Fakultät für Mathematik und Naturwissenschaften, Carl von Ossietzky-Universität Oldenburg; Postfach 2503 26111 Oldenburg Germany
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37
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Hansen N, Wullenkord J, Obenchain DA, Graf I, Kohse-Höinghaus K, Grabow JU. Microwave spectroscopic detection of flame-sampled combustion intermediates. RSC Adv 2017. [DOI: 10.1039/c7ra06483g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Microwave spectroscopy was used to detect and identify combustion intermediates after sampling out of laboratory-scale model flames.
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Affiliation(s)
- N. Hansen
- Combustion Research Facility
- Sandia National Laboratories
- Livermore
- USA
| | - J. Wullenkord
- Department of Chemistry
- Bielefeld University
- D-33615 Bielefeld
- Germany
| | - D. A. Obenchain
- Institut für Physikalische Chemie & Elektrochemie
- Gottfried-Wilhelm-Leibniz-University Hannover
- D-30167 Hannover
- Germany
| | - I. Graf
- Department of Chemistry
- Bielefeld University
- D-33615 Bielefeld
- Germany
| | | | - J.-U. Grabow
- Institut für Physikalische Chemie & Elektrochemie
- Gottfried-Wilhelm-Leibniz-University Hannover
- D-30167 Hannover
- Germany
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38
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Xu F, Shi X, Zhang Q, Wang W. Mechanism for the growth of polycyclic aromatic hydrocarbons from the reactions of naphthalene with cyclopentadienyl and indenyl. CHEMOSPHERE 2016; 162:345-354. [PMID: 27538266 DOI: 10.1016/j.chemosphere.2016.07.039] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Revised: 06/11/2016] [Accepted: 07/13/2016] [Indexed: 06/06/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are globally concerned atmospheric particle-bound pollutants due to their toxicities. A mechanistic understanding of their formation from other environmental sources is of crucial importance for successful prevention of PAH. In the present work, the formation and growth mechanism of PAHs from the reactions of naphthalene with the cyclopentadienyl and indenyl radicals was investigated by using the hybrid density functional theory (DFT) at the MPWB1K/6-311+G(3df,2p)//MPWB1K/6-31+G(d,p) level. The rate constants for the crucial elementary steps were deduced with the aid of the canonical variational transition-state (CVT) theory with the small curvature tunneling (SCT) contribution. The formation of PAHs was involved in six elementary processes including: the addition reaction, ring closure, intramolecular H-shift, C-C cleavage, intramolecular H-shift and unimolecular elimination of CH3 or H. The C-C cleavage steps were revealed as the rate determining steps due to the extremely high barrier. At high temperature conditions like the combustion and pyrolysis of many hydrocarbons, the main products are phenanthrene, 4-methyl-phenanthrene and 1-methyl-phenanthrene from the reactions of naphthalene and cyclopentadienyl, and benzo(a)anthracene, 12-methyl-phenanthrene and 7-methyl-phenanthrene from the reactions of naphthalene and indenyl radicals. The reaction of naphthalene with indenyl radical is slightly more difficult than the reaction of naphthalene with cyclopentadienyl radical because of the bigger HOMO-LUMO orbital energy difference of naphthalene with indenyl relative to that of naphthalene with cyclopentadienyl.
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Affiliation(s)
- Fei Xu
- Environment Research Institute, Shandong University, Jinan, 250100, PR China
| | - Xiangli Shi
- Environment Research Institute, Shandong University, Jinan, 250100, PR China
| | - Qingzhu Zhang
- Environment Research Institute, Shandong University, Jinan, 250100, PR China.
| | - Wenxing Wang
- Environment Research Institute, Shandong University, Jinan, 250100, PR China
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39
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40
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Herbinet O, Rodriguez A, Husson B, Battin-Leclerc F, Wang Z, Cheng Z, Qi F. Study of the Formation of the First Aromatic Rings in the Pyrolysis of Cyclopentene. J Phys Chem A 2016; 120:668-82. [DOI: 10.1021/acs.jpca.5b09203] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Olivier Herbinet
- Laboratoire
Réactions et Génie des Procédés, Université de Lorraine, UMR 7274, BP 20451, 1 rue Grandville, Nancy, F-54000, France
- Laboratoire
Réactions et Génie des Procédés, CNRS, UMR 7274, BP 20451, 1 rue Grandville, Nancy, F-54000, France
| | - Anne Rodriguez
- Laboratoire
Réactions et Génie des Procédés, Université de Lorraine, UMR 7274, BP 20451, 1 rue Grandville, Nancy, F-54000, France
- Laboratoire
Réactions et Génie des Procédés, CNRS, UMR 7274, BP 20451, 1 rue Grandville, Nancy, F-54000, France
| | - Benoit Husson
- Laboratoire
Réactions et Génie des Procédés, Université de Lorraine, UMR 7274, BP 20451, 1 rue Grandville, Nancy, F-54000, France
- Laboratoire
Réactions et Génie des Procédés, CNRS, UMR 7274, BP 20451, 1 rue Grandville, Nancy, F-54000, France
| | - Frédérique Battin-Leclerc
- Laboratoire
Réactions et Génie des Procédés, Université de Lorraine, UMR 7274, BP 20451, 1 rue Grandville, Nancy, F-54000, France
- Laboratoire
Réactions et Génie des Procédés, CNRS, UMR 7274, BP 20451, 1 rue Grandville, Nancy, F-54000, France
| | - Zhandong Wang
- National
Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
| | - Zhanjun Cheng
- National
Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
| | - Fei Qi
- National
Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
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41
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Hemberger P, da Silva G, Trevitt AJ, Gerber T, Bodi A. Are the three hydroxyphenyl radical isomers created equal?--The role of the phenoxy radical. Phys Chem Chem Phys 2015; 17:30076-83. [PMID: 26500055 DOI: 10.1039/c5cp05346c] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have investigated the thermal decomposition of the three hydroxyphenyl radicals (˙C6H4OH) in a heated microtubular reactor. Intermediates and products were identified isomer-selectively applying photoion mass-selected threshold photoelectron spectroscopy with vacuum ultraviolet synchrotron radiation. Similarly to the phenoxy radical (C6H5-O˙), hydroxyphenyl decomposition yields cyclopentadienyl (c-C5H5) radicals in a decarbonylation reaction at elevated temperatures. This finding suggests that all hydroxyphenyl isomers first rearrange to form phenoxy species, which subsequently decarbonylate, a mechanism which we also investigate computationally. Meta- and para-radicals were selectively produced and spectroscopically detectable, whereas the ortho isomer could not be traced due to its fast rethermalization and rapid decomposition in the reactor. A smaller barrier to isomerization to phenoxy was found to be the reason for this observation. Since hydroxyphenyl species may be present under typical sooting conditions in flames, the resonantly stabilized cyclopentadienyl radical adds to the hydrocarbon pool and can contribute to the formation of polycyclic aromatic hydrocarbons, which are precursors in soot formation.
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Affiliation(s)
- P Hemberger
- Molecular Dynamics Group, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
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42
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Knyazev VD, Popov KV. Kinetics of the Self Reaction of Cyclopentadienyl Radicals. J Phys Chem A 2015; 119:7418-29. [DOI: 10.1021/acs.jpca.5b00644] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vadim D. Knyazev
- Research Center for Chemical
Kinetics, Department of Chemistry, The Catholic University of America, Washington, District of Columbia 20064, United States
| | - Konstantin V. Popov
- Research Center for Chemical
Kinetics, Department of Chemistry, The Catholic University of America, Washington, District of Columbia 20064, United States
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43
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Fulara J, Chakraborty A, Nagy A, Filipkowski K, Maier JP. Electronic transitions of C₅H₃⁺ and C₅H₃: neon matrix and CASPT2 studies. J Phys Chem A 2015; 119:2338-43. [PMID: 25180760 DOI: 10.1021/jp506706f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Two absorption systems of C5H3(+) starting at 350 and 345 nm were detected following mass-selective deposition of m/e = 63 ions in a 6 K neon matrix. These are assigned to the 1 (1)A1 ← X (1)A1 electronic transition of 1,2,3,4-pentatetraenylium H2CCCCCH(+) (isomer B(+)) and 1 (1)B2 ← X (1)A1 of penta-1,4-diyne-3-ylium HCCCHCCH(+) (C(+)). The absorptions of neutral C5H3 isomers with onsets at 434.5, 398.3, 369.0, and 267.3 nm are also detected. The first two systems are assigned to the 1 (2)B1 ← X (2)B1 and 1 (2)A2 ← X (2)B1 transitions of isomer B and C, respectively, and the latter two to ethynylcyclopropenyl (A) and 3-vinylidenecycloprop-1-enyl (D) radicals. The structural assignments are based on the adiabatic excitation energies calculated with the MS-CASPT2 method. A vibrational analysis of the electronic spectra, based on the calculated harmonic frequencies, supports this.
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Affiliation(s)
- Jan Fulara
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland
| | - Arghya Chakraborty
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland
| | - Adam Nagy
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland
| | - Karol Filipkowski
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland
| | - John P Maier
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland
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44
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Moshammer K, Jasper AW, Popolan-Vaida DM, Lucassen A, Diévart P, Selim H, Eskola AJ, Taatjes CA, Leone SR, Sarathy SM, Ju Y, Dagaut P, Kohse-Höinghaus K, Hansen N. Detection and Identification of the Keto-Hydroperoxide (HOOCH2OCHO) and Other Intermediates during Low-Temperature Oxidation of Dimethyl Ether. J Phys Chem A 2015; 119:7361-74. [PMID: 25695304 DOI: 10.1021/acs.jpca.5b00101] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this paper we report the detection and identification of the keto-hydroperoxide (hydroperoxymethyl formate, HPMF, HOOCH2OCHO) and other partially oxidized intermediate species arising from the low-temperature (540 K) oxidation of dimethyl ether (DME). These observations were made possible by coupling a jet-stirred reactor with molecular-beam sampling capabilities, operated near atmospheric pressure, to a reflectron time-of-flight mass spectrometer that employs single-photon ionization via tunable synchrotron-generated vacuum-ultraviolet radiation. On the basis of experimentally observed ionization thresholds and fragmentation appearance energies, interpreted with the aid of ab initio calculations, we have identified HPMF and its conceivable decomposition products HC(O)O(O)CH (formic acid anhydride), HC(O)OOH (performic acid), and HOC(O)OH (carbonic acid). Other intermediates that were detected and identified include HC(O)OCH3 (methyl formate), cycl-CH2-O-CH2-O- (1,3-dioxetane), CH3OOH (methyl hydroperoxide), HC(O)OH (formic acid), and H2O2 (hydrogen peroxide). We show that the theoretical characterization of multiple conformeric structures of some intermediates is required when interpreting the experimentally observed ionization thresholds, and a simple method is presented for estimating the importance of multiple conformers at the estimated temperature (∼100 K) of the present molecular beam. We also discuss possible formation pathways of the detected species: for example, supported by potential energy surface calculations, we show that performic acid may be a minor channel of the O2 + ĊH2OCH2OOH reaction, resulting from the decomposition of the HOOCH2OĊHOOH intermediate, which predominantly leads to the HPMF.
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Affiliation(s)
- Kai Moshammer
- †Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States.,‡Department of Chemistry, Bielefeld University, D-33615 Bielefeld, Germany
| | - Ahren W Jasper
- †Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Denisia M Popolan-Vaida
- §Departments of Chemistry and Physics, University of California, Berkeley, California 94720, United States.,∥Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Arnas Lucassen
- †Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Pascal Diévart
- ⊥Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Hatem Selim
- #Clean Combustion Research Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Arkke J Eskola
- †Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Craig A Taatjes
- †Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Stephen R Leone
- §Departments of Chemistry and Physics, University of California, Berkeley, California 94720, United States.,∥Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - S Mani Sarathy
- #Clean Combustion Research Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Yiguang Ju
- ⊥Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Philippe Dagaut
- ∇Centre National de la Recherche Scientifique (CNRS), INSIS, 45071 Orléans Cedex 2, France
| | | | - Nils Hansen
- †Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
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45
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Parker DSN, Kaiser RI, Kostko O, Troy TP, Ahmed M, Sun BJ, Chen SH, Chang AHH. On the formation of pyridine in the interstellar medium. Phys Chem Chem Phys 2015; 17:32000-8. [DOI: 10.1039/c5cp02960k] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The nitrogen bearing aromatic molecule pyridine (C5H5N) is revealed to form in high temperature environments simulating conditions in carbon-rich circumstellar envelopes via the reaction of the cyano vinyl radical with vinyl cyanide.
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Affiliation(s)
| | - Ralf I. Kaiser
- Department of Chemistry
- University of Hawaii at Manoa
- Honolulu
- USA
| | - Oleg Kostko
- Chemical Sciences Division
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
| | - Tyler P. Troy
- Chemical Sciences Division
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
| | - Musahid Ahmed
- Chemical Sciences Division
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
| | - Bing-Jian Sun
- Department of Chemistry
- National Dong Hwa University
- Shoufeng
- Taiwan
| | - Shih-Hua Chen
- Department of Chemistry
- National Dong Hwa University
- Shoufeng
- Taiwan
| | - A. H. H. Chang
- Department of Chemistry
- National Dong Hwa University
- Shoufeng
- Taiwan
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46
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Parker DSN, Kaiser RI, Troy TP, Kostko O, Ahmed M, Mebel AM. Toward the Oxidation of the Phenyl Radical and Prevention of PAH Formation in Combustion Systems. J Phys Chem A 2014; 119:7145-54. [DOI: 10.1021/jp509170x] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Dorian S. N. Parker
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Ralf I. Kaiser
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Tyler P. Troy
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Oleg Kostko
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Musahid Ahmed
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Alexander M. Mebel
- Department of Chemistry and
Biochemistry, Florida International University, Miami, Florida 33199, United States
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47
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Kaiser RI, Dangi BB, Yang T, Parker DSN, Mebel AM. Reaction dynamics of the 4-methylphenyl radical (p-tolyl) with 1,2-butadiene (1-methylallene): are methyl groups purely spectators? J Phys Chem A 2014; 118:6181-90. [PMID: 25084134 DOI: 10.1021/jp505868q] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reactions of the 4-tolyl radical (C6H4CH3) and of the D7-4-tolyl radical (C6D4CD3) with 1,2-butadiene (C4H6) have been probed in crossed molecular beams under single collision conditions at a collision energy of about 54 kJ mol(-1) and studied theoretically using ab initio G3(MP2,CC)//B3LYP/6-311G** and statistical RRKM calculations. The results show that the reaction proceeds via indirect scattering dynamics through the formation of a van-der-Waals complex followed by the addition of the radical center of the 4-tolyl radical to the C1 or C3 carbon atoms of 1,2-butadiene. The collision complexes then isomerize by migration of the tolyl group from the C1 (C3) to the C2 carbon atom of the 1,2-butadiene moiety. The resulting intermediate undergoes unimolecular decomposition via elimination of a hydrogen atom from the methyl group of the 1,2-butadiene moiety through a rather loose exit transition state leading to 2-para-tolyl-1,3-butadiene (p4), which likely presents the major reaction product. Our observation combined with theoretical calculations suggest that one methyl group (at the phenyl group) acts as a spectator in the reaction, whereas the other one (at the allene moiety) is actively engaged in the underlying chemical dynamics. On the contrary to the reaction of the phenyl radical with allene, which leads to the formation of indene, the substitution of a hydrogen atom by a methyl group in allene essentially eliminates the formation of bicyclic PAHs such as substituted indenes in the 4-tolyl plus 1,2-butadiene reaction.
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Affiliation(s)
- Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States
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48
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Hansen N, Skeen SA, Michelsen HA, Wilson KR, Kohse-Höinghaus K. Flame experiments at the advanced light source: new insights into soot formation processes. J Vis Exp 2014. [PMID: 24894694 PMCID: PMC4207224 DOI: 10.3791/51369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The following experimental protocols and the accompanying video are concerned with the flame experiments that are performed at the Chemical Dynamics Beamline of the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory1-4. This video demonstrates how the complex chemical structures of laboratory-based model flames are analyzed using flame-sampling mass spectrometry with tunable synchrotron-generated vacuum-ultraviolet (VUV) radiation. This experimental approach combines isomer-resolving capabilities with high sensitivity and a large dynamic range5,6. The first part of the video describes experiments involving burner-stabilized, reduced-pressure (20-80 mbar) laminar premixed flames. A small hydrocarbon fuel was used for the selected flame to demonstrate the general experimental approach. It is shown how species’ profiles are acquired as a function of distance from the burner surface and how the tunability of the VUV photon energy is used advantageously to identify many combustion intermediates based on their ionization energies. For example, this technique has been used to study gas-phase aspects of the soot-formation processes, and the video shows how the resonance-stabilized radicals, such as C3H3, C3H5, and i-C4H5, are identified as important intermediates7. The work has been focused on soot formation processes, and, from the chemical point of view, this process is very intriguing because chemical structures containing millions of carbon atoms are assembled from a fuel molecule possessing only a few carbon atoms in just milliseconds. The second part of the video highlights a new experiment, in which an opposed-flow diffusion flame and synchrotron-based aerosol mass spectrometry are used to study the chemical composition of the combustion-generated soot particles4. The experimental results indicate that the widely accepted H-abstraction-C2H2-addition (HACA) mechanism is not the sole molecular growth process responsible for the formation of the observed large polycyclic aromatic hydrocarbons (PAHs).
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Affiliation(s)
- Nils Hansen
- Combustion Research Facility, Sandia National Laboratories;
| | - Scott A Skeen
- Combustion Research Facility, Sandia National Laboratories
| | | | - Kevin R Wilson
- Chemical Sciences Division, Advanced Light Source, Lawrence Berkeley National Laboratory
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49
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Lo PK, Lau KC. High-Level ab Initio Predictions for the Ionization Energy, Electron Affinity, and Heats of Formation of Cyclopentadienyl Radical, Cation, and Anion, C5H5/C5H5+/C5H5–. J Phys Chem A 2014; 118:2498-507. [DOI: 10.1021/jp412323j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Po-Kam Lo
- Department of Biology and
Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong
| | - Kai-Chung Lau
- Department of Biology and
Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong
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50
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Dangi BB, Yang T, Kaiser RI, Mebel AM. Reaction dynamics of the 4-methylphenyl radical (C6H4CH3; p-tolyl) with isoprene (C5H8) – formation of dimethyldihydronaphthalenes. Phys Chem Chem Phys 2014; 16:16805-14. [DOI: 10.1039/c4cp01056f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reaction dynamics and energetics of 4-methylphenyl radical with isoprene are reported under single collision condition at collision energy of 58 kJ mol−1 by exploiting the crossed molecular beam technique and electronic structure calculations.
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Affiliation(s)
- Beni B. Dangi
- Department of Chemistry
- University of Hawai'i at Manoa
- Honolulu, USA
| | - Tao Yang
- Department of Chemistry
- University of Hawai'i at Manoa
- Honolulu, USA
| | - Ralf I. Kaiser
- Department of Chemistry
- University of Hawai'i at Manoa
- Honolulu, USA
| | - Alexander M. Mebel
- Department of Chemistry and Biochemistry
- Florida International University
- Miami, USA
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