JOURNAL OF CHEMICAL SCIENCES, vol.121, no.3, pp.267-273, 2009 (SCI-Expanded)
The reaction of aqueous cobaltous nitrate hexahydrate with the anion of succinimide (sucH) in the presence of excess ethylenediamine (en) in air results in the formation of a dinuclear complex mu-peroxo-bis[bis(ethylenediamine)succinimidato-cobalt(III)] dinitrate dihydrate, 1, in good yield. Compound 1 was characterized by elemental analysis, IR, visible spectra and magnetic susceptibility studies. The explosive nature of [Co(en)(2)(suc)(mu-O(2))Co(en)(2)(suc)](NO(3))(2)center dot 2H(2)O, 1, precluded its thermal characterization. Compound 1 crystallises in the monoclinic space group P2(1)/c and a half of the molecule, constitutes its asymmetric unit. In the centrosymmetric dinuclear complex 1, two Co(III) centres, are linked by a planar peroxide bridge. Each cobalt atom is surrounded by four nitrogen atoms of ethylenediamine ligands, a nitrogen atom of succinimidato anion and an oxygen atom of peroxo bridge resulting in a slightly distorted {CoN(5)O} octahedron. Due to steric hindrance between the two Co(III) centres, the peroxide bridge is planar with a Co-O-O-Co torsion angle of 180 degrees. The dinuclear complex cation, the nitrate anion and the lattice water are involved in three varieties of H-bonding interactions namely N-H center dot center dot center dot O, O-H center dot center dot center dot O and C-H center dot center dot center dot O.