Atomic radical—molecule reactions F +  CH3C≡CH: mechanistic study

Li, Jilai; Geng, Caiyun; Huang, Xuri; Sun, Chia‐Chung

doi:10.1007/s00214-006-0169-2

Cited by 4 publications

(3 citation statements)

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“…On top of these difficulties, we are also facing a particular challenging problem: to properly describe the competition between HAT and RAF mechanisms. For example such competition between H abstraction and addition mechanisms has been studied before at CCSD(T)/aug-cc-pVDZ//MP2/6-311++G(d,p) for the reaction of atomic radical F with propyne . Obviously, such a sophisticated level of theory is out the question in the present work.…”

Section: Resultsmentioning

confidence: 86%

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Reactions of OOH Radical with β-Carotene, Lycopene, and Torulene: Hydrogen Atom Transfer and Adduct Formation Mechanisms

Galano

Francisco‐Márquez

2009

J. Phys. Chem. B

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The relative free radical scavenging activity of beta-carotene, lycopene, and torulene toward OOH radicals has been studied using density functional theory. Hydrogen atom transfer (HAT) and radical adduct formation (RAF) mechanisms have been considered. All the possible reaction sites have been included in the modeling, and detailed branching ratios are reported for the first time. The reactions of hydrocarbon carotenoids (Car) with peroxyl radicals, in both polar and nonpolar environments, are predicted to proceed via RAF mechanism, with contributions higher than 98% to the overall OOH + Car reactions. Lycopene and torulene were found to be more reactive than beta-carotene. In nonpolar environments the reactivity of the studied carotenoids toward peroxyl radical follows the trend LYC > TOR > BC, whereas in aqueous solutions it is TOR > LYC > BC. OOH adducts are predicted to be formed mainly at the terminal sites of the conjugated polyene chains. The main addition sites were found to be C5 for beta-carotene and lycopene and C30 for torulene. The general agreement between the calculated magnitudes and the available experimental data supports the predictions from this work.

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Section: Resultsmentioning

confidence: 86%

“…For example such competition between H abstraction and addition mechanisms has been studied before at CCSD(T)/aug-cc-pVDZ//MP2/6-311++G (d,p) for the reaction of atomic radical F with propyne. 33 Obviously, such a sophisticated level of theory is out the question in the present work. Therefore we have used a different strategy.…”

Section: Resultsmentioning

confidence: 88%

Reactions of OOH Radical with β-Carotene, Lycopene, and Torulene: Hydrogen Atom Transfer and Adduct Formation Mechanisms

Galano

Francisco‐Márquez

2009

J. Phys. Chem. B

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“…On the triplet PES, all reaction channels described above for the [Zn(OH)] + -C 3 H 8 system have been calculated to be endothermic (Table S3, ESI ‡); therefore, this spin state has not been considered in further calculations. 70,71 As mentioned above, the reactions of [Zn(OH)] + with ethane and methane have also been studied in the experiments; here, only adduct formations are observed for [Zn(OH)] + -C 2 H 6 ( Fig. S3, ESI ‡).…”

Section: Resultsmentioning

confidence: 99%

Highly regioselective hydride transfer, oxidative dehydrogenation, and hydrogen-atom abstraction in the thermal gas-phase chemistry of [Zn(OH)]⁺/C₃H₈

Zhao

et al. 2014

Phys. Chem. Chem. Phys.

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The thermal reactions of [Zn(OH)](+) with C3H8 have been studied by means of gas-phase experiments and computational investigation. Two types of C-H bond activation are observed in the experiment, and pertinent mechanistic features include inter alia: (i) the metal center of [Zn(OH)](+) serves as active site in the hydride transfer to generate [i-C3H7](+) as major product, (ii) generally, a high regioselectivity is accompanied by remarkable chemoselectivity: for example, the activation of a methyl C-H bond results mainly in the formation of water and [Zn(C3,H7)](+). According to computational work, this ionic product corresponds to [HZn(CH3CH=CH2)](+). Attack of the zinc center at a secondary C-H bond leads preferentially to hydride transfer, thus giving rise to the generation of [i-C3H7](+); (iii) upon oxidative dehydrogenation (ODH), liberation of CH3CH2=CH2 occurs to produce [HZn(H2O)](+). Both, ODH as well as H2O loss proceed through the same intermediate which is characterized by the fact that a methylene hydrogen atom from the substrate is transferred to the zinc and one hydrogen atom from the methyl group to the OH group of [Zn(OH)](+). The combined experimental/computational gas-phase study of C-H bond activation by zinc hydroxide provides mechanistic insight into related zinc-catalyzed large-scale processes and identifies the crucial role that the Lewis-acid character of zinc plays.

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F/Cl + C2H2 reactions: Are the addition and hydrogen abstraction direct processes?

Geng

Huang

et al. 2006

Chemical Physics

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Atomic radical—molecule reactions F + CH3C≡CH: mechanistic study

Cited by 4 publications

References 47 publications

Reactions of OOH Radical with β-Carotene, Lycopene, and Torulene: Hydrogen Atom Transfer and Adduct Formation Mechanisms

Reactions of OOH Radical with β-Carotene, Lycopene, and Torulene: Hydrogen Atom Transfer and Adduct Formation Mechanisms

Highly regioselective hydride transfer, oxidative dehydrogenation, and hydrogen-atom abstraction in the thermal gas-phase chemistry of [Zn(OH)]⁺/C₃H₈

F/Cl + C2H2 reactions: Are the addition and hydrogen abstraction direct processes?

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Atomic radical—molecule reactions F + CH3C≡CH: mechanistic study

Cited by 4 publications

References 47 publications

Reactions of OOH Radical with β-Carotene, Lycopene, and Torulene: Hydrogen Atom Transfer and Adduct Formation Mechanisms

Reactions of OOH Radical with β-Carotene, Lycopene, and Torulene: Hydrogen Atom Transfer and Adduct Formation Mechanisms

Highly regioselective hydride transfer, oxidative dehydrogenation, and hydrogen-atom abstraction in the thermal gas-phase chemistry of [Zn(OH)]+/C3H8

F/Cl + C2H2 reactions: Are the addition and hydrogen abstraction direct processes?

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Highly regioselective hydride transfer, oxidative dehydrogenation, and hydrogen-atom abstraction in the thermal gas-phase chemistry of [Zn(OH)]⁺/C₃H₈