Infrared Spectrum of the Propargyl Peroxyl Radical, HC C-CH2OO (X)(2)A'

Evan B. Jochnowitz; Xu Zhang; Mark R. Nimlos; Bradley A. Flowers; John F. Stanton; G. Barney Ellison

doi:10.1021/jp907806g

Infrared Spectrum of the Propargyl Peroxyl Radical, HC C-CH2OO (X)(2)A'

Evan B. Jochnowitz, Xu Zhang, Mark R. Nimlos, Bradley A. Flowers, John F. Stanton, G. Barney Ellison

Renewable Resources and Enabling Sciences Center

Research output: Contribution to journal › Article › peer-review

13 Scopus Citations

Abstract

When the propargyl radical, HCCCH₂, and O₂ are codeposited onto a cold argon matrix, a chemical reaction ensues; infrared absorption spectra reveal the formation of the propargyl peroxyl radical:HC=C-CH₂X̃²B₁ + O ₂→trans-HC=C-CH₂OOX̃²A We do not observe the isomeric adduct, CH₂=C=CHOO X̃ ²A″. The propargyl radicals are produced by a hyperthermal nozzle while a second nozzle alternately fires bursts of O₂/Ar at the 20 K matrix. The absorption spectra of the radicals are measured using a Fourier transform infrared spectrometer. We observe 13 of the 18 fundamental infrared bands of the propargyl peroxyl radical in an Ar matrix at 20 K. The experimental frequencies (cm^-1) of trans-}HC=C -CH₂OO X̃ ²A″ are assigned. The a' modes are V₁ = 3326, V₂ = 2960, V₃ = 2148, V₄ = 1440, V₅ = 1338, V₆ = 1127, V₇ = 982, V⁸ = 928, V⁹ = 684, and v₁₀ = 499 cm^-1, while the a′ modes are v ₁₄ = 1218, V₁₅ = 972, and V₁₆= 637 cm ^-1. Linear dichroism spectra were measured with photo-oriented HCCCH₂OO radical samples to establish the experimental polarizations of several vibrational bands. The experimental frequencies (v) for the propargyl peroxyl radical are compared to the anharmonic frequencies (v) resulting from electronic structure calculations. We have used CBS-QB3 electronic structure calculations to estimate the peroxyl bond energies: δH ₂₉₈(trans-HC=CCH₂-OO -CH₂CCH X̃²B, + O₂) = 19 ± 1 kcal mol-1 and δH₂₉₈(transCH₂=C=CH-OO -CH₂CCH X̃ ²B₁ + O₂) = 21 ± 1 kcal mol ^-1. The experimental thermochemistry for C₃H3́ reacting with oxygen has been reanalyzed as δ_rxnH ₂₉₈(HCCCH₂ + O₂→ CH₃=C==O + HCO) = -83 ± 3 kcal mol^-1; δ_rxnH ₂₉₈(HCCCH₂ + O₂→CH₃CO + CO) = -111 ± 3 kcal mol^-1; δ_rxnH ₂₉₈(HCCCH₂ + O₂ -CH₂CHO + CO) = -106 ± 4 kcal mol^-1; δ_rxnH₂₉₈(HCCCH2 + O₂→HCHO + HCCO) = -67 ± 4 kcal mol^-1; δ_rxnH₂₉₈(HCCCH₂ + O₂→ CH₂CH + CO₂) = -105 ± 3 kcal mol^-1.

Original language	American English
Pages (from-to)	1498-1507
Number of pages	10
Journal	Journal of Physical Chemistry A
Volume	114
Issue number	3
DOIs	https://doi.org/10.1021/jp907806g https://doi.org/10.1021/jp907806g
State	Published - 2010

NREL Publication Number

NREL/JA-510-47575

Keywords

HCCCH2
propargyl peroxyl radical

Access to Document

Cite this

@article{a5ede7f469d44d608ddfaff383515643,

title = "Infrared Spectrum of the Propargyl Peroxyl Radical, HC C-CH2OO (X)(2)A'",

abstract = "When the propargyl radical, HCCCH2, and O2 are codeposited onto a cold argon matrix, a chemical reaction ensues; infrared absorption spectra reveal the formation of the propargyl peroxyl radical:HC=C-CH2{\~X}2B1 + O 2→trans-HC=C-CH2OO{\~X}2A We do not observe the isomeric adduct, CH2=C=CHOO {\~X} 2A″. The propargyl radicals are produced by a hyperthermal nozzle while a second nozzle alternately fires bursts of O2/Ar at the 20 K matrix. The absorption spectra of the radicals are measured using a Fourier transform infrared spectrometer. We observe 13 of the 18 fundamental infrared bands of the propargyl peroxyl radical in an Ar matrix at 20 K. The experimental frequencies (cm-1) of trans-}HC=C -CH2OO {\~X} 2A″ are assigned. The a' modes are V1 = 3326, V2 = 2960, V3 = 2148, V4 = 1440, V5 = 1338, V6 = 1127, V7 = 982, V8 = 928, V9 = 684, and v10 = 499 cm-1, while the a′ modes are v 14 = 1218, V15 = 972, and V16= 637 cm -1. Linear dichroism spectra were measured with photo-oriented HCCCH2OO radical samples to establish the experimental polarizations of several vibrational bands. The experimental frequencies (v) for the propargyl peroxyl radical are compared to the anharmonic frequencies (v) resulting from electronic structure calculations. We have used CBS-QB3 electronic structure calculations to estimate the peroxyl bond energies: δH 298(trans-HC=CCH2-OO -CH2CCH {\~X}2B, + O2) = 19 ± 1 kcal mol-1 and δH298(transCH2=C=CH-OO -CH2CCH {\~X} 2B1 + O2) = 21 ± 1 kcal mol -1. The experimental thermochemistry for C3H{\'3} reacting with oxygen has been reanalyzed as δrxnH 298(HCCCH2 + O2→ CH3=C==O + HCO) = -83 ± 3 kcal mol-1; δrxnH 298(HCCCH2 + O2→CH3CO + CO) = -111 ± 3 kcal mol-1; δrxnH 298(HCCCH2 + O2 -CH2CHO + CO) = -106 ± 4 kcal mol-1; δrxnH298(HCCCH2 + O2→HCHO + HCCO) = -67 ± 4 kcal mol-1; δrxnH298(HCCCH2 + O2→ CH2CH + CO2) = -105 ± 3 kcal mol-1.",

keywords = "HCCCH2, propargyl peroxyl radical",

author = "Jochnowitz, {Evan B.} and Xu Zhang and Nimlos, {Mark R.} and Flowers, {Bradley A.} and Stanton, {John F.} and Ellison, {G. Barney}",

year = "2010",

doi = "10.1021/jp907806g",

language = "American English",

volume = "114",

pages = "1498--1507",

journal = "Journal of Physical Chemistry A",

issn = "1089-5639",

publisher = "American Chemical Society",

number = "3",

}

TY - JOUR

T1 - Infrared Spectrum of the Propargyl Peroxyl Radical, HC C-CH2OO (X)(2)A'

AU - Jochnowitz, Evan B.

AU - Zhang, Xu

AU - Nimlos, Mark R.

AU - Flowers, Bradley A.

AU - Stanton, John F.

AU - Ellison, G. Barney

PY - 2010

Y1 - 2010

N2 - When the propargyl radical, HCCCH2, and O2 are codeposited onto a cold argon matrix, a chemical reaction ensues; infrared absorption spectra reveal the formation of the propargyl peroxyl radical:HC=C-CH2X̃2B1 + O 2→trans-HC=C-CH2OOX̃2A We do not observe the isomeric adduct, CH2=C=CHOO X̃ 2A″. The propargyl radicals are produced by a hyperthermal nozzle while a second nozzle alternately fires bursts of O2/Ar at the 20 K matrix. The absorption spectra of the radicals are measured using a Fourier transform infrared spectrometer. We observe 13 of the 18 fundamental infrared bands of the propargyl peroxyl radical in an Ar matrix at 20 K. The experimental frequencies (cm-1) of trans-}HC=C -CH2OO X̃ 2A″ are assigned. The a' modes are V1 = 3326, V2 = 2960, V3 = 2148, V4 = 1440, V5 = 1338, V6 = 1127, V7 = 982, V8 = 928, V9 = 684, and v10 = 499 cm-1, while the a′ modes are v 14 = 1218, V15 = 972, and V16= 637 cm -1. Linear dichroism spectra were measured with photo-oriented HCCCH2OO radical samples to establish the experimental polarizations of several vibrational bands. The experimental frequencies (v) for the propargyl peroxyl radical are compared to the anharmonic frequencies (v) resulting from electronic structure calculations. We have used CBS-QB3 electronic structure calculations to estimate the peroxyl bond energies: δH 298(trans-HC=CCH2-OO -CH2CCH X̃2B, + O2) = 19 ± 1 kcal mol-1 and δH298(transCH2=C=CH-OO -CH2CCH X̃ 2B1 + O2) = 21 ± 1 kcal mol -1. The experimental thermochemistry for C3H3́ reacting with oxygen has been reanalyzed as δrxnH 298(HCCCH2 + O2→ CH3=C==O + HCO) = -83 ± 3 kcal mol-1; δrxnH 298(HCCCH2 + O2→CH3CO + CO) = -111 ± 3 kcal mol-1; δrxnH 298(HCCCH2 + O2 -CH2CHO + CO) = -106 ± 4 kcal mol-1; δrxnH298(HCCCH2 + O2→HCHO + HCCO) = -67 ± 4 kcal mol-1; δrxnH298(HCCCH2 + O2→ CH2CH + CO2) = -105 ± 3 kcal mol-1.

AB - When the propargyl radical, HCCCH2, and O2 are codeposited onto a cold argon matrix, a chemical reaction ensues; infrared absorption spectra reveal the formation of the propargyl peroxyl radical:HC=C-CH2X̃2B1 + O 2→trans-HC=C-CH2OOX̃2A We do not observe the isomeric adduct, CH2=C=CHOO X̃ 2A″. The propargyl radicals are produced by a hyperthermal nozzle while a second nozzle alternately fires bursts of O2/Ar at the 20 K matrix. The absorption spectra of the radicals are measured using a Fourier transform infrared spectrometer. We observe 13 of the 18 fundamental infrared bands of the propargyl peroxyl radical in an Ar matrix at 20 K. The experimental frequencies (cm-1) of trans-}HC=C -CH2OO X̃ 2A″ are assigned. The a' modes are V1 = 3326, V2 = 2960, V3 = 2148, V4 = 1440, V5 = 1338, V6 = 1127, V7 = 982, V8 = 928, V9 = 684, and v10 = 499 cm-1, while the a′ modes are v 14 = 1218, V15 = 972, and V16= 637 cm -1. Linear dichroism spectra were measured with photo-oriented HCCCH2OO radical samples to establish the experimental polarizations of several vibrational bands. The experimental frequencies (v) for the propargyl peroxyl radical are compared to the anharmonic frequencies (v) resulting from electronic structure calculations. We have used CBS-QB3 electronic structure calculations to estimate the peroxyl bond energies: δH 298(trans-HC=CCH2-OO -CH2CCH X̃2B, + O2) = 19 ± 1 kcal mol-1 and δH298(transCH2=C=CH-OO -CH2CCH X̃ 2B1 + O2) = 21 ± 1 kcal mol -1. The experimental thermochemistry for C3H3́ reacting with oxygen has been reanalyzed as δrxnH 298(HCCCH2 + O2→ CH3=C==O + HCO) = -83 ± 3 kcal mol-1; δrxnH 298(HCCCH2 + O2→CH3CO + CO) = -111 ± 3 kcal mol-1; δrxnH 298(HCCCH2 + O2 -CH2CHO + CO) = -106 ± 4 kcal mol-1; δrxnH298(HCCCH2 + O2→HCHO + HCCO) = -67 ± 4 kcal mol-1; δrxnH298(HCCCH2 + O2→ CH2CH + CO2) = -105 ± 3 kcal mol-1.

KW - HCCCH2

KW - propargyl peroxyl radical

UR - http://www.scopus.com/inward/record.url?scp=77249149438&partnerID=8YFLogxK

U2 - 10.1021/jp907806g

DO - 10.1021/jp907806g

M3 - Article

AN - SCOPUS:77249149438

SN - 1089-5639

VL - 114

SP - 1498

EP - 1507

JO - Journal of Physical Chemistry A

JF - Journal of Physical Chemistry A

IS - 3

ER -

Infrared Spectrum of the Propargyl Peroxyl Radical, HC C-CH2OO (X)(2)A'

Abstract

NREL Publication Number

Keywords

Access to Document

Other files and links

Fingerprint

Cite this