Peroxo complexes bimetallic

An 02 ligand can bind the two metals in bimetallic /z-peroxo complexes in a variety of coordination modes (Scheme 3). Also, tetranuclear /z-peroxo derivatives of the type indicated in Scheme 3 are known. 

Synthesis of bimetallic /r-peroxo complexes has been described by Mimoun. In particular, for Co species reaction between a superoxo complex with a reduced metal is a feasible method, for Pt species acid catalyzed hydrolysis of peroxo complex may be used and for Rh or Pd the protocol implies reaction of potassium superoxide with appropriate precursors. 

Solid state structures for bimetallic /r-peroxo complexes have been obtained for aU the coordination modes of 02 moiety indicated in Scheme 3. Several examples can be found in a special issue of Chemical Reviews. ... 

Dicobalt /it-peroxo complexes have been synthesized di-Co(III) species, [Co2(bpmp)(/r-02)(/z-CH3C02)](C104) 29, was reported by Kofod and coworkers. Di-Co(II) complex, 31 [Co2(/z-02)(oxapyme(N02)]+, has been prepared starting from the corresponding [Co2(/z- -02)(oxapyme)]+ species 30, as indicated in equation 13 . Both species were characterized in the solid state and interesting aspects of transformation of dioxygen ligand in bimetallic species were therefore explored. 

In complexes (3), (7) and (8), dioxygen can be inserted between two metal atoms (bimetallic //-peroxo complexes), between one metal and one carbon atom (alkylperoxo complexes) or between one metal and one hydrogen atom (hydroperoxo complexes). 

To achieve the four-electron reduction of O2 to H2O without releasing H2O2 another metal ion such as Cu ion in cytochrome c oxidase is required to stabilize the two-electron reduced peroxy species by forming a bimetallic peroxo complex. This... 

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