Theoretical study of the reaction mechanism of ethynyl radical with benzene and related reactions on the C8H7 potential energy surface

Landera, Alexander; Mebel, Alexander M.; Kaiser, Ralf I.

doi:10.1016/j.cplett.2008.05.043

Cited by 24 publications

(45 citation statements)

References 31 publications

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“…Within the experimental error limits, this yields a reaction exoergicity of 121 ( 10 kJ mol -1 . This value is in direct agreement to those derived from ab initio electronic structure calculations 37 of 111 ( 10 kJ mol -1 and from standard enthalpy values taken from the NIST database. 62 Second, the translational energy distribution peaks well away from zero translational energy at about 44 kJ mol -1 .…”

Section: Center Of Mass Functions the Center-of-mass Angular T(θ)supporting

confidence: 87%

“…On the basis of these findings, we propose that the ethynyld 1 radical adds to the benzene-d 6 molecule to form a C 6 D 6 CCD intermediate, the latter fragmenting via atomic deuterium loss, forming the phenylacetylene-d 6 molecule. These findings and the suggested reaction mechanism gain full support from the computed potential energy surfaces ( Figure 7) adapted from Landera et al 37 In this figure, only the pathways leading to the formation of phenylacetylene are shown. It should be stressed that our reaction was conducted with ethynyl-d 1 and benzened 6 .…”

Section: Discussionsupporting

confidence: 65%

“…Note that previous electronic structure calculations 37,38 predicted multiple thermodynamically stable C 8 H 6 isomers such as cyclic C 8 H 6 . However, among all the possible isomers synthesized, the only molecule formed in the ethynyl-d 1 plus benzene-d 6 reaction via an exoergic process was the phenylaceteylene-d 6 species.…”

Section: Discussionmentioning

confidence: 82%

“…Consequently, the pathways relevant to the reaction dynamics on the formation of phenylacetylene have been recalculated to account for the difference in the zero point energy. The computational methods employed were described in ref 37. As seen in Figure 7, two reaction pathways are possible.…”

Section: Discussionmentioning

confidence: 99%

“…36 Since these studies only monitored the decay kinetics of the open shell species, the product(s) was/ were unidentifiable. Also, recent ab initio studies by Landera et al 37 and Woon 38 confirm that the reaction of ethynyl radical with benzene proceeds without an entrance barrier; two thermodynamically favored pathways were identified, leading ultimately to the formation of phenylacetylene on the C 8 H 7 potential energy surface. Both pathways involve the formation of an adduct via addition of the ethynyl radical to the benzene ring without entrance barriers.…”

Section: Introductionmentioning

confidence: 89%

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Crossed Molecular Beam Study on the Formation of Phenylacetylene and Its Relevance to Titan’s Atmosphere

et al. 2010

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The crossed molecular beam experiment of the deuterated ethynyl radical (C 2 D; X 2 Σ + ) with benzene [C 6 H 6 (X 1 A 1g )] and its fully deuterated analog [C 6 D 6 (X 1 A 1g )] was conducted at a collision energy of 58.1 kJ mol -1 . Our experimental data suggest the formation of the phenylacetylene-d 6 via indirect reactive scattering dynamics through a long-lived reaction intermediate; the reaction is initiated by a barrierless addition of the ethynyl-d 1 radical to benzene-d 6 . This initial collision complex was found to decompose via a tight exit transition state located about 42 kJ mol -1 above the separated products; here, the deuterium atom is ejected almost perpendicularly to the rotational plane of the decomposing intermediate and almost parallel to the total angular momentum vector. The overall experimental exoergicity of the reaction is shown to be 121 ( 10 kJ mol -1 ; this compares nicely with the computed reaction energy of -111 kJ mol -1 . Even though the experiment was conducted at a collisional energy higher than equivalent temperatures typically found in the atmosphere of Titan (94 K and higher), the reaction may proceed in Titan's atmosphere as it involves no entrance barrier, all transition states involved are below the energy of the separated reactants, and the reaction is exoergic. Further, the phenylacetylene was found to be the sole reaction product.

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Section: Center Of Mass Functions the Center-of-mass Angular T(θ)supporting

confidence: 87%

Section: Discussionsupporting

confidence: 65%

Section: Discussionmentioning

confidence: 82%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 89%

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Crossed Molecular Beam Study on the Formation of Phenylacetylene and Its Relevance to Titan’s Atmosphere

et al. 2010

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Gas‐Phase Synthesis of the Elusive Cyclooctatetraenyl Radical (C₈H₇) via Triplet Aromatic Cyclooctatetraene (C₈H₈) and Non‐Aromatic Cyclooctatriene (C₈H₈) Intermediates

et al. 2017

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The 1,2,4,7-cyclooctatetraenyl radical (C 8 H 7 )h as been synthesized for the very first time via the bimolecular gasphase reaction of ground-state carbon atoms with 1,3,5-cycloheptatriene (C 7 H 8 )onthe triplet surface under single-collision conditions.T he barrier-less route to the cyclic 1,2,4,7-cyclooctatetraenyl radical accesses exotic reaction intermediates on the triplet surface,w hichc annot be synthesized via classical organic chemistry methods:t he triplet non-aromatic 2,4,6cyclooctatriene (C 8 H 8 )a nd the triplet aromatic 1,3,5,7-cyclooctatetraene (C 8 H 8 ). Our approach provides aclean gas-phase synthesis of this hitherto elusive cyclic radical species 1,2,4,7cyclooctatetraenyl via as ingle-collision event and opens up av ersatile,u nconventional path to access this previously largely obscure class of cyclooctatetraenyl radicals,which have been impossible to access through classical synthetic methods. Scheme 1. Structures of 1,3,5,7-cyclooctatetraene (1)a long with transition states for ring inversion (2)a nd bond-shifting isomerization processes (3). The point groups are also indicated.

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Gas‐Phase Synthesis of the Elusive Cyclooctatetraenyl Radical (C₈H₇) via Triplet Aromatic Cyclooctatetraene (C₈H₈) and Non‐Aromatic Cyclooctatriene (C₈H₈) Intermediates

et al. 2017

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The 1,2,4,7-cyclooctatetraenyl radical (C H ) has been synthesized for the very first time via the bimolecular gas-phase reaction of ground-state carbon atoms with 1,3,5-cycloheptatriene (C H ) on the triplet surface under single-collision conditions. The barrier-less route to the cyclic 1,2,4,7-cyclooctatetraenyl radical accesses exotic reaction intermediates on the triplet surface, which cannot be synthesized via classical organic chemistry methods: the triplet non-aromatic 2,4,6-cyclooctatriene (C H ) and the triplet aromatic 1,3,5,7-cyclooctatetraene (C H ). Our approach provides a clean gas-phase synthesis of this hitherto elusive cyclic radical species 1,2,4,7-cyclooctatetraenyl via a single-collision event and opens up a versatile, unconventional path to access this previously largely obscure class of cyclooctatetraenyl radicals, which have been impossible to access through classical synthetic methods.

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Theoretical study of the reaction mechanism of ethynyl radical with benzene and related reactions on the C8H7 potential energy surface

Cited by 24 publications

References 31 publications

Crossed Molecular Beam Study on the Formation of Phenylacetylene and Its Relevance to Titan’s Atmosphere

Crossed Molecular Beam Study on the Formation of Phenylacetylene and Its Relevance to Titan’s Atmosphere

Gas‐Phase Synthesis of the Elusive Cyclooctatetraenyl Radical (C₈H₇) via Triplet Aromatic Cyclooctatetraene (C₈H₈) and Non‐Aromatic Cyclooctatriene (C₈H₈) Intermediates

Gas‐Phase Synthesis of the Elusive Cyclooctatetraenyl Radical (C₈H₇) via Triplet Aromatic Cyclooctatetraene (C₈H₈) and Non‐Aromatic Cyclooctatriene (C₈H₈) Intermediates

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Theoretical study of the reaction mechanism of ethynyl radical with benzene and related reactions on the C8H7 potential energy surface

Cited by 24 publications

References 31 publications

Crossed Molecular Beam Study on the Formation of Phenylacetylene and Its Relevance to Titan’s Atmosphere

Crossed Molecular Beam Study on the Formation of Phenylacetylene and Its Relevance to Titan’s Atmosphere

Gas‐Phase Synthesis of the Elusive Cyclooctatetraenyl Radical (C8H7) via Triplet Aromatic Cyclooctatetraene (C8H8) and Non‐Aromatic Cyclooctatriene (C8H8) Intermediates

Gas‐Phase Synthesis of the Elusive Cyclooctatetraenyl Radical (C8H7) via Triplet Aromatic Cyclooctatetraene (C8H8) and Non‐Aromatic Cyclooctatriene (C8H8) Intermediates

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Product

Resources

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Gas‐Phase Synthesis of the Elusive Cyclooctatetraenyl Radical (C₈H₇) via Triplet Aromatic Cyclooctatetraene (C₈H₈) and Non‐Aromatic Cyclooctatriene (C₈H₈) Intermediates

Gas‐Phase Synthesis of the Elusive Cyclooctatetraenyl Radical (C₈H₇) via Triplet Aromatic Cyclooctatetraene (C₈H₈) and Non‐Aromatic Cyclooctatriene (C₈H₈) Intermediates