Redox and spin-trapping properties of phosphoryldithioacetates

The redox properties of ethyl diethoxyphosphoryldithioacetate (1), methyl diethoxyphosphorylfluorodithioacetate (2) and methyl diethoxyphosphoryldifluorodithioacetate (3) were measured by cyclic voltammetry. Addition of free radicals to the three dithioesters led to the detection of the ESR spectra of the spin adducts only with the last two compounds. Based on the reduction potentials of the three dithioacetates, this may be explained by capto-dative stabilization of the adducts. On the basis of DFT calculations, the temperature dependent variations of the spectral patterns exhibited by the radicals were attributed to restricted rotation about the C-alpha-SMe bond.