摘要：

Tertiary arsine complexes of cobalt form stable monomeric and dimeric dioxygen adducts. Reaction of oxygen with formally cobalt(I)-arsine complexes produces "sideways" bonded dioxygen adducts. The cobalt(III)-diaquoarsine complexes react with hydrogen peroxide to give the same monomeric adducts. This latter reaction proceeds rapidly by a catalytic pathway and more slowly by what appears to be a "simple" substitution process where optical activity is retained when the active cis-[Co(diars)2(OH2)2]3+ ion is used as the substrate. The robust chemical behavior of these monomeric complexes is similar to other analogous cobalt(III)-arsine compounds and their visible electronic absorption spectra clearly indicate that the species are best regarded as cobalt(III)-peroxide complexes. The significance of this conclusion in relation to bond length data is briefly discussed. Reaction of oxygen with cobalt(II) arsines leads to the production of dimeric dioxygen-bridge adducts, the absorption spectra and chemical properties of which indicate that these too are Co(III) species but with a peroxide bridging ligand. The monomeric dioxygen adducts react with sulfur dioxide to give the bidentate sulfato complexes which have been prepared and characterized, some in optically active forms. Dimeric (formally) Co(II) complexes containing Co-Co bonds disproportionate in the presence of strong bases to give Co(I) species which react with oxygen to give the "sideways" bonded dioxygen adducts.

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