Über Reaktionen oxygenierter Kobalt(II)‐Chelate. VI. Präparative Darstellung von diastereoisomeren Tetrakis(äthylendiamin)‐μ‐peroxo‐μ‐hydroxodikobalt(III)‐perchloraten

On Reactions of oxygenated Cobalt(II) Chelates. VI. Preparation of diastereoisomeric tetrakis(ethylenediamine)‐μ‐peroxo‐μl‐hydroxo‐dicobalt(III) Perchlorates Oxygenation of Co(en)22+ leads to a mixture of two isomeric forms of [(en)2Co(O2, OH)‐Co(en)2] (ClO4)3 · H2O from which the less soluble meso form can be readily crystallized. Further crystallization from the mother liquor yields the racemate ΔΔ/ΔΔ. The pure racemate may be obtained by either of the following methods: (a) By ligand exchange starting from mono bridged [(NH3)5CoO2Co(NH3)5] (NO3)4 or from doubly bridged [(SCN) (NH3)3Co(O2, OH)Co(NH3)3(SCN)] SCN · 2H2O. (b) By reaction of cis‐[Co(en)2(OH2)2]3+ with H2O2. Reaction (b) proceeds via an intermediate cis‐[Co(en)2(OOH) (OH2)] (ClO4)2 · H2O which at higher pH reacts with [Co(en)2(OH) (OH2)]2+ to yield the desired doubly bridged ΔΔ/ΔΔ tetrakis(ethylenediamine)‐μ‐peroxo‐μ‐hydroxodikobalt(III)‐perchlorate.