The Electron Spin Resonance Spectra of the Photochemically Produced Perfluorobenzophenone Ketyl and Anion Radicals

The electron spin resonance spectra of the ketyl and radical anion of perfluorobenzophenone were generated in alcoholic solution by means of a photochemical method. The radical anion was prepared in alkaline solutions by means of a flow system to prevent nucleophillic degradation of the perfluorobenzophenone prior to photolysis. A comparison is made of the fluorine nuclear hyperfme coupling constants to those reported for partially fluorinated radical anions.

THE REACTIONS OF PERFLUOROETHYL RADICALS WITH HYDROGEN AND METHANE

The reactions of C2F5 radicals, produced by the photolysis of (C2F5)2CO, with methane and hydrogen have been studied. Assuming zero activation energy for 2C2F5 → C4F10 the activation energies for C2F5 + CH4 → C2F5H + CH3 and C2F5 + H2 → C2F5H + H are 10.6 kcal/mole and 11.9 kcal/mole respectively. The present results have been correlated with data on the reactions of CF3, C3F7, and CH3 radicals with H2, D2, CH4, and C2H6. Taking Erecombination ≈ 0 in all cases and assuming the frequency factor for the recombination reaction varies little from radical to radical, the order of ease of hydrogen abstraction from a given substrate is CF3 > C2F5 > C3F7 > CH3. Similarly the ease of hydrogen abstraction from a substrate by a given fluorinated radical is C2H6 > H2 > CH4 > D2. A calculation based on very limited data indicates the reaction CH3 + C2F5COC2F5 → CH3COC2F5 + C2F5 may occur with an activation energy of approximately 7 kcal/mole.