Peroxo complexes binuclear

DR. HENRY TAUBE (Stanford University) Another interesting point about Collman s complex should be noted. Let us presume that a peroxide intermediate is generated in his case. In all of Dr. Endicott s examples, the remarkable observation is that it is very difficult to reduce the 0-0 bond kinetically in the binuclear p-peroxo complexes. In Collman s case, this reduction... 

An unusual peroxo-bridged binuclear iridium complex containing an Ir—Ir bond has been reported (135a, 135b). The reaction of the electron-... 

Oxygen Ligands Table 6 Binuclear Peroxo Complexes... 

Several diverse metal centres are involved in the catalysis of monooxygenation or hydroxylation reactions. The most important of these is cytochrome P-450, a hemoprotein with a cysteine residue as an axial ligand. Tyrosinase involves a coupled binuclear copper site, while dopamine jS-hydroxylase is also a copper protein but probably involves four binuclear copper sites, which are different from the tyrosinase sites. Putidamonooxin involves an iron-sulfur protein and a non-heme iron. In all cases a peroxo complex appears to be the active species. 

Clague MJ, Butler A (1995) On the Mechanism of < 7 v- Dioxovanad ium(V)-Catalyzed Oxidation of Bromide by Hydrogen Peroxide Evidence for a Reactive, Binuclear Vanadi-um(V) Peroxo Complex. J Am Chem Soc 117 3475... 

Recent reviews on the chemistry of metal-dioxygen complexes with particular relevance to cobalt systems include a number dealing with general properties,636,634 1 binuclear superoxo and peroxo complexes,642,643 reversible oxygenation,644-646 complex stability,647,448 catalytic oxidation649,650 and electronic651 and EPR652 spectral properties. 

Binuclear vanadium(V) peroxo complexes such as (NH4)5[V202(02)4P04]-H20 are also known.30 They have been implicated as the reactive species in the bromide oxidation by hydrogen peroxide,31 a process which is important in some biological systems (Section 17-B-8). Some stable peroxo compounds display insulin-mimetic activity both in vivo and in vitro.32... 

The electronic structiue of the fragment [0s020s] is not clear. However, we assume that this binuclear cation exists as peroxo complex, Cp20s (02 )Os Cp2. Binuclear peroxo complexes of this type frequently photolyze imder elimination of oxygen in general and 2 in particular (22). 

Copper(I) complexes similarly react with dioxygen to form peroxo-bridged binuclear complexes.Such complexes do not readily undergo O—O bond cleavage, apparently because the copper(III) oxidation state is not as readily attainable as the Fe(IV) oxidation state in an iron-porphyrin complex. Nevertheless, stable peroxo complexes of copper(II) have been difficult to obtain, because, as soon as it is formed, the peroxo complex either is protonated to give free hydrogen peroxide or is itself reduced by more copper(I) (Reactions 5.42 to 5.46). 

Recently, however, examples of the long-sought stable binuclear copper(II) peroxo complex have been successfully synthesized and characterized, and interestingly enough, two entirely different structural types have been identified, i.e., /u,-l,2 and dioxygen complexes(see 5.47)... 

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