Spectroscopic observation of the resonance-stabilized 1-phenylpropargyl radical.
The gas-phase laser-induced fluorescence (LIF) spectrum of a 1-phenylpropargyl radical has been identified in the region 20,800-22,000 cm(-1) in a free jet. The radical was produced from discharges of hydrocarbons including benzene. Disregarding C2, C3, and CH, this radical appears as the most strongly fluorescing product in a visible wavelength two-dimensional fluorescence excitation-emission spectrum of a jet-cooled benzene discharge. The structure of the carrier was elucidated by measurement of a matching resonant two-color two-photon ionization spectrum at m/z = 115 and density functional theory. The assignment was proven conclusively by observation of the same excitation spectrum from a low-current discharge of 3-phenyl-1-propyne. The apparent great abundance of the 1-phenylpropargyl radical in discharges of benzene and, more importantly, 1-hexyne may further underpin the proposed importance of the propargyl radical in the formation of complex hydrocarbons in combustion and circumstellar environments.
Reilly
Neil J
NJ
School of Chemistry, University of Sydney, NSW 2006, Australia.
Kokkin
Damian L
DL
Nakajima
Masakazu
M
Nauta
Klaas
K
Kable
Scott H
SH
Schmidt
Timothy W
TW
D000480:Alkynes / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D007834:Lasers; D008956:Models, Chemical; D015394:Molecular Structure; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods
D000480:Alkynes; D005609:Free Radicals