A heterodinuclear Co(II)Cu(I) complex with Co(salen) in a macrocyclic framework. Oxygenation studies in comparison with analogous Cu(II)Cu(I) and Co(II)Pb(II) complexes

Misato Shinoura, Satoru Kita, Masaaki Ohba, Hisashi Okawa, Hideki Furutachi, Masatatsu Suzuki

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27 Citations (Scopus)

Abstract

A di(μ-phenoxo)Co(II)Cu(I) complex, [CoCu(L)]ClO4·0.5DMF, has been prepared where (L)2- is a macrocyclic dinucleating 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 monoclinic space 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) Å, and Z = 4. The Co(II) resides in the salen-like site and assumes a planar geometry. The Cu(I) in the N2O2S site has a planar four-coordinate geometry with two phenolic oxygens and two imine nitrogens; the thioether sulfur on the lateral chain is situated at an axial site of the Cu(I), 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 two Cu-N bond distances (1.984(6) and 1.929(4) Å). Further, the N-Cu-N angle is very large (128.2(2)°), whereas the O-Cu-O angle is very small (65.2(2)°). Analogous Cu(II)Cu(I) and Co(II)Pb(II) complexes of (L)2-, [Cu(II)Cu(I)(L)]ClO4 and [CoPb(L)](ClO4)2, have been prepared. The DMF adduct of [Cu(II)Cu(I)(L)]ClO4, [Cu(II)Cu(I)(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 Co(II)Cu(I) complex and shows distortions about the Cu(I) similar to those found for the Co(II)Cu(I) complex. The di-DMF adduct of the Co(II)Pb(II) 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 Co(II) in the N2O2 site has a square-pyramidal geometry together with a DMF oxygen at the apical site. The Pb(II) in the N2O2S site has a six-coordinate geometry with the further coordination of a DMF molecule. The reactivity of the Co(II)Cu(I) complex toward dioxygen has been studied in comparison with the Cu(II)Cu(I) and Co(II)Pb(II) complexes. The Co(II)Cu(I) complex in DMF is very sensitive to dioxygen and is oxidized at -50 °C. The Cu(II)Cu(I) complex is inert to dioxygen. The Co(II)Pb(II) complex is oxygenated at 0 °C to form a peroxo dimer (Pb(II)Co(III)-O-O-Co(III)Pb(II)). The high sensitivity of the Co(II)Cu(I) complex to dioxygen is explained by the irreversible oxidation to a Co(III)Cu(II) species through an intramolecular-type peroxo complex (Co(III)-O-O-Cu(II)).

Original languageEnglish
Pages (from-to)4520-4526
Number of pages7
JournalInorganic chemistry
Volume39
Issue number20
DOIs
Publication statusPublished - Oct 2 2000

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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