Abstract: The substituent parameters for the pentafluorophenyl group have been determined by classical pK. measurements and'9F nmr calibrations on the appropriate pentafluorobiphenyl derivatives. The pentafluorophenyl group inductively withdraws electrons more strongly than a phenyl group but much less than a trifluoromethyl group. Resonance effects were not significant but would be prevented in these systems by steric ...
