Monobridged complexes

The reaction of iodide with [(en)2Co( r-OH)( -02)Co(en)2] in acid solution gives [Co(en)2(OH2)2] and iodine. The rate has been shown to be the same as that of dissociation in acid solution (reaction 12) and the initial step is hydrolysis of the /i-hydroxo group followed by I" attack on the monobridged species. The monobridged complex [(H3N)5Co(02)Co(NH3)5] produced by iodide reduction of the superoxo complex does not react with iodide but decomposes to Co(II) and ammonia The reduction of the mononuclear -peroxo complex [(H3N)5Co(02)Co(NH3)s] by or... 

After chromatographic separation, monobridged complexes 9(Mo, W) easily transformed to the dibridged compounds 10(Mo, W) by photochemical elimination... 

In turn, the tantalum phosphine complex 3(Ta) gives dibridged structures ll(Ta), which are accompanied, in some cases, by small amounts of monobridged complexes. ... 

Thus, there should be no direct metal-metal interaction in monobridged complexes. Note that the values of M-P-M angles in monobridged compounds are the largest observed for sp hybridized phosphorus atoms. This is certainly due to the steric... 

Selected structural data for /i-peroxo cobalt(III) complexes are included in Table 57. Orbital diagrams constructed for Co—O—O bonds in N4Co(02)CoN4 species show that irons bent bonds are the most stable and this is what is observed for the monobridged complexes. Dibridging forces the /i-peroxo group to adopt a skewed cis geometry except in cases (e.g. [(tren)Co(/i-tren,02)Co-... 

Until recently the starting material for all amido-bridged complexes of cobalt was Vortmann s sulfate.1 In the much improved procedure described here, the monobridged M-peroxo complex is first prepared and then converted into the /x-peroxo-jtt-amido complex.5... 

Structural parameters of monobridged dimeric super0X0 and peroxo complexes... 

Another group of cobalt(11) complexes that show catalytic activity in 2,6-DTBP oxidation to the corresponding BQ and DPQ has been described by Bedell and Martell [56]. They are 1 1 Co(II) polyamine chelates (with the ligands listed below), some of which form monobridged p-peroxo complexes with dioxygen, whereas others afford dibridged (p-peroxo)(p-hydroxo) derivatives with the ligands listed in Table II. 

Reactivity of dinuclear iron complexes with simple bidentate ligands such as 2,2 -bipyridine and 1,10-phenanthroline for oxidation of alkanes, toluene, dimethyl sulfide, trans-stilbene and adamantane was studied in CHjCN under Ar in the presence of oxidants (TBHP, CHP or H2O2). The effect of the number of the bridging ligand was found remarkable monobridged Fe20(L)4(X)2(C104)4 >... 

Bis-cyclopentadienyl complexes are also seen the example of Y (Eq. 15.32) shows how LiCl can form an adduct with the product—an adduct that is only cleaved at 285°. Note how the monobridged structure of the product in Eq. 15.32 contrasts with the bis-bridged (CpaYf/i-CljaYCpa], again resulting from steric differences, this time between Cp and Cp. ... 

---