Catalytic disproportionation of N-alkylhydroxylamines bound to pentacyanoferrates

Abstract

The substituted hydroxylamines, CH3N(H)OH (N-methylhydroxylamine) and (CH3)2NOH (N,N-dimethylhydroxylamine), disproportionate catalytically to the corresponding alkylamines and oxidation products, only in the presence of [Fe(CN)5H2O]3−. Substitution kinetic measurements suggest an initial coordination step to Fe(ii). Two parallel N- and O-coordination modes are considered with the subsequent formation of Fe(iii), free aminyl (RNCH3) and nitroxide (RN(CH3)O) radicals (R = H, CH3). With CH3N(H)OH, bound nitrosomethane, CH3NO, has been characterized by UV-visible and IR spectroscopies. The mechanism is discussed on the basis of common and differential features with respect to the disproportionation of hydroxylamine catalyzed by the same Fe-fragment.