Reactions of µ-hydroxo-dicobalt complexes. Part III. Reactions of the µ-amido-µ-hydroxo-bis[tetra-amminecobalt(III)] complex with con-centrated acids and the identification of new complexes

Abstract

Spectrophotometric and kinetic studies of reactions occurring when increasing amounts of concentrated acids are added to the perchlorate salt of the µ-amido-µ-hydroxo-bis [tetra-amminecobalt(III)] complexes, (NH₃)₄Co·µ(NH₂,OH)-Co(NH₃)₄⁴⁺, are reported. With increasing concentration of hydrocholoric acid (0–11·3M), the µ-amido-aquo-chloro- and µ-amido-bischloro-complexes, (NH₃)₄(H₂O)Co·NH₂·Co(Cl)(NH₃)₄⁴⁺, and (NH₃)₄(CI)Co·NH₂·Co(CI)(NH₃)₄³⁺ respectively, are formed. Small quantities of the µ-amido-µ-chloro-complex, (NH₃)₄Co·µ(NH₂·Cl)·Co-Co(NH₃)₄⁴⁺, are also believed to be present. With perchloric acid the µ-amido-µ-aquo-and µ-amido-bisaquo-complexes are first formed; at higher acid concentrations (>8M) the µ-amido-aquo-perchlorato-and µ-amido-µ-aquo-perchlorato-complexes, (NH₃)₄(H₂O)Co·NH₂·Co(ClO₄)(NH₃)₄⁴⁺ and (NH₃)₄Co·µ(NH₂,ClO₄)Co(NH₃)₄⁴⁺, respectively, are obtained. The effects of nitric and sulphuric acid are also considered.