Infrared and EPR Spectroscopic Studies of 2-C₂H₂F and 1-C₂H₂F Radicals Isolated in Solid Argon

Author： Goldschleger I.U. Akimov A.V. Misochko E.Y. Wight C.A.

ISSN： 0022-2852

Source： Journal of Molecular Spectroscopy, Vol.205, Iss.2, 2001-02, pp. : 269-279

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Abstract

2-fluorovinyl radicals were generated in solid argon by solid-state chemical reactions of mobile F atoms with acetylene and its deuterated analogues. Highly resolved EPR spectra of the stabilized radicals CHF=^•CH, CDF=^•CD, CHF=^•CD, and CDF=^•CH were obtained for the first time. The observed spectra were assigned to cis-2-fluorovinyl radical based on excellent agreement between the measured (a_F = 6.50, a_βH = 3.86, a_αH = 0.25 mT) hyperfine constants and those calculated using density functional (B3LYP) theory. Analogous experiments carried out using infrared spectroscopy yielded a complete assignment of the vibrational frequencies. An unusual reversible photochemical conversion is observed in which cis-2-fluorovinyl radicals can be partially converted to 1-fluorovinyl radicals by pulsed laser photolysis at 532 nm. Photolysis at 355 nm converts 1-fluorovinyl back to cis-2-fluorovinyl. High-resolution EPR and infrared spectra of 1-fluorovinyl were obtained for the first time. The measured hyperfine constants (a_F = 13.71, a_H1 = 4.21, a_H2 = 1.16 mT) are in good agreement with calculated values.