Synthesis and structural characterization of a novel peroxo bridged dinuclear cobalt(III) complex of succinimide showing three varieties of hydrogen bonding interactions

Abstract

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.