[en] The kinetics of the reaction between ruthenium pentaammine pyrazine and acetonitrile pentacyanoferrate (II) to obtain the binuclear anionic complex [Fe(CN)₅pzRu(NH₃)₅]^-, and the reverse (dissociation) process, have been studied in solutions containing DNA. The results corresponding to this reaction and those corresponding to the reverse (dissociation) process show a clear influence of DNA on their kinetics. The results can be interpreted using a modified Pseudophase Model. From the results obtained for the dissociation reaction one can conclude that the binuclear anionic complex [Fe(CN)₅pzRu(NH₃)₅]^- interacts with DNA