Radical substituent effects of alpha-fluorine and alpha-trifluoromethyl groups

Research was conducted to evaluate the radical substituent effects of fluorine and trifluoromethyl groups from the computed C-H homolytic bond dissociation enthalpies of 30 fluorinated compounds. Results showed a strengthening of the sp(super 3) C-H bond with the introduction of three alpha-fluorine substituents. However, the entry of one or two substituents resulted in the weakening of C-H bond strength due to resonance delocalization.