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Marchione D, Mancini L, Liang P, Vanuzzo G, Pirani F, Skouteris D, Rosi M, Casavecchia P, Balucani N. Unsaturated Dinitriles Formation Routes in Extraterrestrial Environments: A Combined Experimental and Theoretical Investigation of the Reaction between Cyano Radicals and Cyanoethene (C 2H 3CN). J Phys Chem A 2022; 126:3569-3582. [PMID: 35640168 PMCID: PMC9189926 DOI: 10.1021/acs.jpca.2c01802] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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The reaction between
cyano radicals (CN, X2Σ+) and cyanoethene
(C2H3CN) has been
investigated by a combined approach coupling crossed molecular beam
(CMB) experiments with mass spectrometric detection and time-of-flight
analysis at a collision energy of 44.6 kJ mol–1 and
electronic structure calculations to determine the relevant potential
energy surface. The experimental results can be interpreted by assuming
the occurrence of a dominant reaction pathway leading to the two but-2-enedinitrile
(1,2-dicyanothene) isomers (E- and Z-NC–CH=CH–CN) in a H-displacement channel and,
to a much minor extent, to 1,1-dicyanoethene, CH2C(CN)2. In order to derive the product branching ratios under the
conditions of the CMB experiments and at colder temperatures, including
those relevant to Titan and to cold interstellar clouds, we have carried
out RRKM statistical calculations using the relevant potential energy
surface of the investigated reaction. We have also estimated the rate
coefficient at very low temperatures by employing a semiempirical
method for the treatment of long-range interactions. The reaction
has been found to be barrierless and fast also under the low temperature
conditions of cold interstellar clouds and the atmosphere of Titan.
Astrophysical implications and comparison with literature data are
also presented. On the basis of the present work, 1,2-dicyanothene
and 1,1-dicyanothene are excellent candidates for the search of dinitriles
in the interstellar medium.
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Affiliation(s)
- Demian Marchione
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Luca Mancini
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Pengxiao Liang
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Gianmarco Vanuzzo
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Fernando Pirani
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | | | - Marzio Rosi
- Dipartimento di Ingegneria Civile ed Ambientale, Università degli Studi di Perugia, 06125 Perugia, Italy
| | - Piergiorgio Casavecchia
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Nadia Balucani
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
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Mancini L, Vanuzzo G, Marchione D, Pannacci G, Liang P, Recio P, Rosi M, Skouteris D, Casavecchia P, Balucani N. The Reaction N( 2D) + CH 3CCH (Methylacetylene): A Combined Crossed Molecular Beams and Theoretical Investigation and Implications for the Atmosphere of Titan. J Phys Chem A 2021; 125:8846-8859. [PMID: 34609869 PMCID: PMC8521525 DOI: 10.1021/acs.jpca.1c06537] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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The reaction of excited
nitrogen atoms N(2D) with CH3CCH (methylacetylene)
was investigated under single-collision
conditions by the crossed molecular beams (CMB) scattering method
with mass spectrometric detection and time-of-flight analysis at the
collision energy (Ec) of 31.0 kJ/mol.
Synergistic electronic structure calculations of the doublet potential
energy surface (PES) were performed to assist the interpretation of
the experimental results and characterize the overall reaction micromechanism.
Theoretically, the reaction is found to proceed via a barrierless addition of N(2D) to the carbon–carbon
triple bond of CH3CCH and an insertion of N(2D) into the CH bond of the methyl group, followed
by the formation of cyclic and linear intermediates that can undergo
H, CH3, and C2H elimination or isomerize to
other intermediates before unimolecularly decaying to a variety of
products. Kinetic calculations for addition and insertion mechanisms
and statistical (Rice-Ramsperger-Kassel-Marcus) computations of product
branching fractions (BFs) on the theoretical PES were performed at
different values of total energy, including the one corresponding
to the temperature (175 K) of Titan’s stratosphere and that
of the CMB experiment. Up to 14 competing product channels were statistically
predicted, with the main ones, at Ec =
31.0 kJ/mol, being the formation of CH2NH (methanimine)
+ C2H (ethylidyne) (BF = 0.41), c-C(N)CH
+ CH3 (BF = 0.32), CH2CHCN (acrylonitrile) +
H (BF = 0.12), and c-CH2C(N)CH + H (BF
= 0.04). Of the 14 possible channels, seven correspond to H displacement
channels of different exothermicity, for a total H channel BF of ∼0.25
at Ec = 31.0 kJ/mol. Experimentally, dynamical
information could only be obtained about the overall H channels. In
particular, the experiment corroborates the formation of acrylonitrile
+ H, which is the most exothermic of all 14 reaction channels and
is theoretically calculated to be the dominant H-forming channel (BF
= 0.12). The products containing a novel C–N bond could be
potential precursors to form other nitriles (C2N2, C3N) or more complex organic species containing N atoms
in planetary atmospheres, such as those of Titan and Pluto. Overall,
the results are expected to have a potentially significant impact
on the understanding of the gas-phase chemistry of Titan’s
atmosphere and the modeling of that atmosphere.
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Affiliation(s)
- Luca Mancini
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Gianmarco Vanuzzo
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Demian Marchione
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Giacomo Pannacci
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Pengxiao Liang
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Pedro Recio
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Marzio Rosi
- Dipartimento di Ingegneria Civile e Ambientale, Università degli Studi di Perugia, 06125 Perugia, Italy
| | | | - Piergiorgio Casavecchia
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Nadia Balucani
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
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Sleiman C, El Dib G, Rosi M, Skouteris D, Balucani N, Canosa A. Low temperature kinetics and theoretical studies of the reaction CN + CH 3NH 2: a potential source of cyanamide and methyl cyanamide in the interstellar medium. Phys Chem Chem Phys 2018; 20:5478-5489. [PMID: 29082409 DOI: 10.1039/c7cp05746f] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction between cyano radicals (which are ubiquitous in interstellar clouds) and methylamine (a molecule detected in various interstellar sources) has been investigated in a synergistic experimental and theoretical study. The reaction has been found to be very fast in the entire range of temperatures investigated (23-297 K) by using a CRESU apparatus coupled to pulsed laser photolysis - laser induced fluorescence. The global experimental rate coefficient is given by In addition, dedicated electronic structure calculations of the underlying potential energy surface have been performed, together with capture theory and RRKM calculations. The experimental data have been interpreted in the light of the theoretical calculations and the product branching ratio has been established. According to the present study, in the range of temperatures investigated the title reaction is an efficient interstellar route of formation of cyanamide, NH2CN, another interstellar species. The second most important channel is the one leading to methyl cyanamide, CH3NHCN (an isomer of aminoacetonitrile), via a CN/H exchange mechanism with a yield of 12% of the global reaction in the entire range of temperatures explored. For a possible inclusion in future astrochemical models we suggest, by referring to the usual expression the following values: α = 3.68 × 10-12 cm3 molec-1 s-1, β = -1.80, γ = 7.79 K for the channel leading to NH2CN + CH3; α = 5.05 × 10-13 cm3 molec-1 s-1, β = -1.82, γ = 7.93 K for the channel leading to CH3NHCN + H.
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Affiliation(s)
- Chantal Sleiman
- Institut de Physique de Rennes, UMR 6251 du CNRS - Université de Rennes 1, Bat. 11C, Campus de Beaulieu, 263 Avenue du Général Leclerc, F-35042 Rennes Cedex, France.
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Yang T, Dangi BB, Kaiser RI, Bertels LW, Head-Gordon M. A Combined Experimental and Theoretical Study on the Formation of the 2-Methyl-1-silacycloprop-2-enylidene Molecule via the Crossed Beam Reactions of the Silylidyne Radical (SiH; X(2)Π) with Methylacetylene (CH3CCH; X(1)A1) and D4-Methylacetylene (CD3CCD; X(1)A1). J Phys Chem A 2016; 120:4872-83. [PMID: 26837568 DOI: 10.1021/acs.jpca.5b12457] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The bimolecular gas-phase reactions of the ground-state silylidyne radical (SiH; X(2)Π) with methylacetylene (CH3CCH; X(1)A1) and D4-methylacetylene (CD3CCD; X(1)A1) were explored at collision energies of 30 kJ mol(-1) under single-collision conditions exploiting the crossed molecular beam technique and complemented by electronic structure calculations. These studies reveal that the reactions follow indirect scattering dynamics, have no entrance barriers, and are initiated by the addition of the silylidyne radical to the carbon-carbon triple bond of the methylacetylene molecule either to one carbon atom (C1; [i1]/[i2]) or to both carbon atoms concurrently (C1-C2; [i3]). The collision complexes [i1]/[i2] eventually isomerize via ring-closure to the c-SiC3H5 doublet radical intermediate [i3], which is identified as the decomposing reaction intermediate. The hydrogen atom is emitted almost perpendicularly to the rotational plane of the fragmenting complex resulting in a sideways scattering dynamics with the reaction being overall exoergic by -12 ± 11 kJ mol(-1) (experimental) and -1 ± 3 kJ mol(-1) (computational) to form the cyclic 2-methyl-1-silacycloprop-2-enylidene molecule (c-SiC3H4; p1). In line with computational data, experiments of silylidyne with D4-methylacetylene (CD3CCD; X(1)A1) depict that the hydrogen is emitted solely from the silylidyne moiety but not from methylacetylene. The dynamics are compared to those of the related D1-silylidyne (SiD; X(2)Π)-acetylene (HCCH; X(1)Σg(+)) reaction studied previously in our group, and from there, we discovered that the methyl group acts primarily as a spectator in the title reaction. The formation of 2-methyl-1-silacycloprop-2-enylidene under single-collision conditions via a bimolecular gas-phase reaction augments our knowledge of the hitherto poorly understood silylidyne (SiH; X(2)Π) radical reactions with small hydrocarbon molecules leading to the synthesis of organosilicon molecules in cold molecular clouds and in carbon-rich circumstellar envelopes.
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Affiliation(s)
- Tao Yang
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States
| | - Beni B Dangi
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States
| | - Luke W Bertels
- Department of Chemistry, University of California, Berkeley , Berkeley, California 94720, United States
| | - Martin Head-Gordon
- Department of Chemistry, University of California, Berkeley , Berkeley, California 94720, United States
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Preston TJ, Hornung B, Pandit S, Harvey JN, Orr-Ewing AJ. Dynamical Effects and Product Distributions in Simulated CN + Methane Reactions. J Phys Chem A 2016; 120:4672-82. [DOI: 10.1021/acs.jpca.5b09487] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Thomas J. Preston
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| | - Balázs Hornung
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| | - Shubhrangshu Pandit
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| | - Jeremy N. Harvey
- Department
of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven (Heverlee), Belgium
| | - Andrew J. Orr-Ewing
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
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Trevitt AJ, Goulay F. Insights into gas-phase reaction mechanisms of small carbon radicals using isomer-resolved product detection. Phys Chem Chem Phys 2016; 18:5867-82. [DOI: 10.1039/c5cp06389b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Gas-phase radical reactions of CN and CH with small hydrocarbons are overviewed with emphasis on isomer-resolved product detection.
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Affiliation(s)
- Adam J. Trevitt
- School of Chemistry
- University of Wollongong
- Wollongong
- Australia
| | - Fabien Goulay
- Department of Chemistry
- West Virginia University
- Morgantown
- USA
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Casavecchia P, Leonori F, Balucani N. Reaction dynamics of oxygen atoms with unsaturated hydrocarbons from crossed molecular beam studies: primary products, branching ratios and role of intersystem crossing. INT REV PHYS CHEM 2015. [DOI: 10.1080/0144235x.2015.1039293] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Balucani N, Cartechini L, Casavecchia P, Homayoon Z, Bowman JM. A combined crossed molecular beam and quasiclassical trajectory study of the Titan-relevant N( 2D) + D 2O reaction. Mol Phys 2015. [DOI: 10.1080/00268976.2015.1028499] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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10
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Homayoon Z, Bowman JM, Balucani N, Casavecchia P. Quasiclassical Trajectory Calculations of the N((2)D) + H2O Reaction Elucidating the Formation Mechanism of HNO and HON Seen in Molecular Beam Experiments. J Phys Chem Lett 2014; 5:3508-3513. [PMID: 26278601 DOI: 10.1021/jz501757s] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The N((2)D) + H2O is a reaction with competitive product channels, passing through several intermediates. Dynamics of this reaction had been investigated by two of the present authors at two collision energies, Ec, using the crossed molecular beams mass spectrometric method ( Faraday Discuss. 2001 , 119 , 27 - 49 ). The complicated mechanism of this reaction and puzzling results encouraged us to investigate the reaction in a joint experimental/theoretical study. Quasiclassical trajectory (QCT) calculations on an ab initio potential energy surface describing all channels of the title reaction are done with a focus on the N/H exchange channels. Interesting results of QCT calculations, in very good agreement with experimental data, reveal subtle details of the reaction dynamics of the title reaction to HNO/HON + H exit channels by disentangling the different routes to formation of the two possible HNO/HON isomers and therefore assisting in a critical manner the derivation of the reaction mechanism. Results of the present study show that the nonstatistical HNOH intermediate governs exit channels; therefore, the HON channel is as important as that of HNO. The study also confirms that the H2 + NO molecular channel is negligible even though the barrier to its formation is calculated to be well below the reactant asymptote.
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Affiliation(s)
- Zahra Homayoon
- †Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
| | - Joel M Bowman
- †Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
| | - Nadia Balucani
- ‡Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Piergiorgio Casavecchia
- ‡Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
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Farahani P, Maeda S, Francisco JS, Lundberg M. Mechanisms for the Breakdown of Halomethanes through Reactions with Ground-State Cyano Radicals. Chemphyschem 2014; 16:181-90. [DOI: 10.1002/cphc.201402601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Indexed: 11/07/2022]
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Parker DSN, Mebel AM, Kaiser RI. The role of isovalency in the reactions of the cyano (CN), boron monoxide (BO), silicon nitride (SiN), and ethynyl (C2H) radicals with unsaturated hydrocarbons acetylene (C2H2) and ethylene (C2H4). Chem Soc Rev 2014; 43:2701-13. [DOI: 10.1039/c3cs60328h] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The classification of chemical reactions based on shared characteristics is at the heart of the chemical sciences, and is well exemplified by Langmuir's concept of isovalency, in which ‘two molecular entities with the same number of valence electrons have similar chemistries’.
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Affiliation(s)
- D. S. N. Parker
- Department of Chemistry
- University of Hawai'i at Manoa
- Honolulu, USA
| | - A. M. Mebel
- Department of Chemistry and Biochemistry
- Florida International University
- Miami, USA
| | - R. I. Kaiser
- Department of Chemistry
- University of Hawai'i at Manoa
- Honolulu, USA
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Leonori F, Skouteris D, Petrucci R, Casavecchia P, Rosi M, Balucani N. Combined crossed beam and theoretical studies of the C(1D) + CH4 reaction. J Chem Phys 2013; 138:024311. [DOI: 10.1063/1.4773579] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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