Water replacement on the decaaqua-di-rhodium(II) cation; synthesis of superoxo and peroxo rhodium(III) complexes with N-donor ligands

The decaaqua-di-rhodium(II) cation has been found to be an interesting starting material in the preparation of dioxygen complexes with different N-donor ligands. Treatment of aqueous HClO4 solution of [Rh-2(H2O)(10)](4+) with NH4OH/NH3, py and/or en results in water exchange and the formation of corresponding [Rh-2(II)(H2O)(10-m)(base)(n)(OH)(m)]((4-m)+) derivatives. Reaction of the latter with dioxygen afforded superoxo and/or peroxo complexes, depending on reaction conditions: [Rh-2(III)(O-2(-))(NH3)(8)(OH)(2)](ClO4)(3) (1), [Rh-2(III)(O-2(-))(NH3)(8)(OH)(H2O)](ClO4)(4) (2), [Rh-2(III)(O-2(2-))(NH3)(10)](ClO4)(4)(.)6H(2)O (3), [Rh-2(III)(O-2(-))(py)(8)(H2O)(2)](ClO4)(5) (4), [Rh-2(III)(O-2(2-))(en)(4)(H2O)(2)](ClO4)(4) (5) and [Rh-2(III)(O-2(-))(en)(4)(H2O)(2)](ClO4)(5) (6). All the obtained complexes were characterized by elemental analysis, mass spectrometry, UV-Vis, IR and ESR spectroscopies and magnetic measurements. (C) 2004 Elsevier B.V. All rights reserved.