Formation of Baudisch complexes [FeII(CN)5,RNO]3– from alkyl- and aryl-hydroxylamines and aquapentacyanoferrate(3–) anions, [FeII(CN)5,H2O]3–

Abstract

Aqueous sodium aquapentacyanoferrate(3–) reacts with phenylhydroxylamine at pH 7–10 under nitrogen to give the purple complex of Baudisch in approximate accord with equation (i). The free radicals PhNHO· and PhNH·[Fe(CN)₅,H₂O]^3–+ 2PhNHOH =[Fe(CN)₅,PhNO]^3–+ PhNH₂+ 2H₂O (i) participate in the reaction process. Aliphatic hydroxylamines react similarly at pH 5–8 to give pink solutions containing analogous anions, of a type hitherto unknown except for the Legal complexes of aliphatic aldehydes and ketones. The reactions with aliphatic hydroxylamines are slower and more complex, rearrangements of alkylaminyl radicals being involved. Spectrographic and e.s.r. studies have been used to elucidate the mechanisms of these reactions.