Matrix isolation study of the reaction of oxygen atoms with tribromofluoromethane in argon and oxygen matrices at 14 K. FTIR spectra of CBr3F, of COBrF, of the FCO radical, and of the O-18 isotopomers

The photooxidation of tribromofluoromethane isolated in an ozone/argon matrix and in an oxygen matrix has been studied by FTIR spectroscopy. Photolysis of CBr3F with ultraviolet radiation (lambda > 240 nm) in these matrices leads to the formation of carbonyl bromide fluoride, COBrF, and bromine. Further irradiation in the visible (lambda > 350 nm) leads to the rupture of the C-Br bond of COBrF and the formation of the fluorocarbonyl radical, FCO, and bromine atoms. COBrF is reformed on heating the matrix. It is believed that the peroxide FC(O)O-2 has been detected, this being formed when the FCO radical combines with O-2. The FCO radicals can also combine with themselves to form COF2, which has been detected here, in the form of a COF2...Br2 complex. The photooxidation of CBr3F in solid oxygen is also reported; this matrix appears to stabilize the peroxide. The products have been identified using time- and wavelength-dependent photolysis and heating. Separate experiments were conducted using O-18(3) in place of ozone of normal isotopic distribution, in order to assist in making the band assignments.