| Abstract
| - A di(μ-phenoxo)CoIICuI complex with a Co(salen) entity in a macrocyclic framework is oxidized with dioxygen into a CuIIICuII species at −50 °C, through an intramolecular peroxo complex (CuIII−O−O−CuII).
- A di(μ-phenoxo)CoIICuI complex, [CoCu(L)]ClO4·0.5DMF, has been prepared where (L)2- is a macrocyclicdinucleating compartmental ligand derived from the 2:1:1 condensation of 2,6-diformyl-4-methylphenol,ethylenediamine, and 3-thia-1,5-pentanediamine, having a salen-like N2O2 metal-binding site (salen = N,N‘-ethylenedisalicylideneaminate) and an N2O2S site sharing the phenolic oxygens. It crystallizes in the monoclinicspace group P21/n, a = 7.087(1) Å, b = 19.593(6) Å, c = 19.447(3) Å, β = 96.29(1)°, V = 2684(1) Å3, and Z= 4. The CoII resides in the salen-like site and assumes a planar geometry. The CuI in the N2O2S site has a planarfour-coordinate geometry with two phenolic oxygens and two imine nitrogens; the thioether sulfur on the lateralchain is situated at an axial site of the CuI, but the Cu--S separation is very large (3.08 Å). In the {CuN2O2}chromophore, the two Cu−O bond distances (2.333(5) and 2.385(5) Å) are significantly long relative to the twoCu−N bond distances (1.984(6) and 1.929(4) Å). Further, the N−Cu−N angle is very large (128.2(2)°), whereasthe O−Cu−O angle is very small (65.2(2)°). Analogous CuIICuI and CoIIPbII complexes of (L)2-, [CuIICuI(L)]ClO4 and [CoPb(L)](ClO4)2, have been prepared. The DMF adduct of [CuIICuI(L)]ClO4, [CuIICuI(L)]ClO4·0.5DMF,crystallizes in the monoclinic space group P21/n, a = 6.957(2) Å, b = 23.774(2) Å, c = 7.758(3) Å, β = 94.72(3)°, V = 1278.8(6) Å3, and Z = 4. The dinuclear core resembles that of the CoIICuI complex and shows distortionsabout the CuI similar to those found for the CoIICuI complex. The di-DMF adduct of the CoIIPbII complex, [CoPb(L)(DMF)2](ClO4)2, crystallizes in the monoclinic space group P21/n, a = 16.265(2) Å, b = 12.640(2) Å, c =18.584(3) Å, β = 90.43(1)°, V = 3820.5(8) Å3, and Z = 4. The CoII in the N2O2 site has a square-pyramidalgeometry together with a DMF oxygen at the apical site. The PbII in the N2O2S site has a six-coordinate geometrywith the further coordination of a DMF molecule. The reactivity of the CoIICuI complex toward dioxygen hasbeen studied in comparison with the CuIICuI and CoIIPbII complexes. The CoIICuI complex in DMF is very sensitiveto dioxygen and is oxidized at −50 °C. The CuIICuI complex is inert to dioxygen. The CoIIPbII complex isoxygenated at 0 °C to form a peroxo dimer (PbIICoIII−O−O−CoIIIPbII). The high sensitivity of the CoIICuI complexto dioxygen is explained by the irreversible oxidation to a CoIIICuII species through an intramolecular-type peroxocomplex (CoIII−O−O−CuII).
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