AEROBIC OXIDATION OF HYDROCARBONS CATALYZED BY ELECTRONEGATIVE IRON SALEN COMPLEXES

A number of salen derivatives bearing electronegative substituents and their corresponding iron(III) chloro complexes have been prepared. Se veral of the complexes catalyze aerobic oxidation of cyclohexene, prim arily to allylic oxidation products. Evidence supports a radical chain autoxidation mechanism, with the complex functioning to decompose int ermediate alkyl hydroperoxides. Activity is observed only for complexe s with relatively high Fe(III/II) reduction potentials, but the incomp lete correlation of activity with potential indicates that more subtle structural and electronic effects also play an important role in dete rmining the rates of the catalytic reactions.