Large primary kinetic isotope effects in the abstraction of hydrogen from organic compounds by a fluorinated radical in water

Abstract

Isotope effects have been measured for the abstraction of hydrogen from a series of organic substrates by the perfluoro radical, Na⁺⁻O₃SCF₂CF₂OCF₂CF₂˙, in water. Both primary and secondary deuterium isotope effects were measured, with the primary isotope effects ranging in value from 4.5 for isopropanol to 19.6 for acetic acid. The values for the α- and β-secondary deuterium isotope effects were 1.06 and 1.035, respectively. It was concluded that tunneling contributes significantly to the production of the observed, large primary kinetic isotope effects in these C–H abstraction reactions.