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A combined experimental and computational study on the reaction dynamics of the 1-propynyl radical (CH3CC; X2A1) with ethylene (H2CCH2; X1A1g) and the formation of 1-penten-3-yne (CH2CHCCCH3; X1A').
Phys Chem Chem Phys. 2019 Oct 28; 21(40):22308-22319.PC

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.

Authors+Show Affiliations

Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, USA. ralfk@hawaii.edu.Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, USA. ralfk@hawaii.edu.Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, USA. ralfk@hawaii.edu.Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, USA. mebela@fiu.edu and Samara National Research University, Samara 443086, Russia.Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, USA. mebela@fiu.edu and Samara National Research University, Samara 443086, Russia.Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, USA. ralfk@hawaii.edu.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31576858

Citation

He, Chao, et al. "A Combined Experimental and Computational Study On the Reaction Dynamics of the 1-propynyl Radical (CH3CC; X2A1) With Ethylene (H2CCH2; X1A1g) and the Formation of 1-penten-3-yne (CH2CHCCCH3; X1A')." Physical Chemistry Chemical Physics : PCCP, vol. 21, no. 40, 2019, pp. 22308-22319.
He C, Zhao L, Thomas AM, et al. A combined experimental and computational study on the reaction dynamics of the 1-propynyl radical (CH3CC; X2A1) with ethylene (H2CCH2; X1A1g) and the formation of 1-penten-3-yne (CH2CHCCCH3; X1A'). Phys Chem Chem Phys. 2019;21(40):22308-22319.
He, C., Zhao, L., Thomas, A. M., Galimova, G. R., Mebel, A. M., & Kaiser, R. I. (2019). A combined experimental and computational study on the reaction dynamics of the 1-propynyl radical (CH3CC; X2A1) with ethylene (H2CCH2; X1A1g) and the formation of 1-penten-3-yne (CH2CHCCCH3; X1A'). Physical Chemistry Chemical Physics : PCCP, 21(40), 22308-22319. https://doi.org/10.1039/c9cp04073k
He C, et al. A Combined Experimental and Computational Study On the Reaction Dynamics of the 1-propynyl Radical (CH3CC; X2A1) With Ethylene (H2CCH2; X1A1g) and the Formation of 1-penten-3-yne (CH2CHCCCH3; X1A'). Phys Chem Chem Phys. 2019 Oct 28;21(40):22308-22319. PubMed PMID: 31576858.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A combined experimental and computational study on the reaction dynamics of the 1-propynyl radical (CH3CC; X2A1) with ethylene (H2CCH2; X1A1g) and the formation of 1-penten-3-yne (CH2CHCCCH3; X1A'). AU - He,Chao, AU - Zhao,Long, AU - Thomas,Aaron M, AU - Galimova,Galiya R, AU - Mebel,Alexander M, AU - Kaiser,Ralf I, Y1 - 2019/10/02/ PY - 2019/10/3/pubmed PY - 2019/10/3/medline PY - 2019/10/3/entrez SP - 22308 EP - 22319 JF - Physical chemistry chemical physics : PCCP JO - Phys Chem Chem Phys VL - 21 IS - 40 N2 - 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. SN - 1463-9084 UR - https://www.unboundmedicine.com/medline/citation/31576858/A_combined_experimental_and_computational_study_on_the_reaction_dynamics_of_the_1_propynyl_radical__CH3CC L2 - https://doi.org/10.1039/c9cp04073k DB - PRIME DP - Unbound Medicine ER -
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