Ligand properties of quadridentate Schiff's bases. The crystal and molecular structure of the mixed-ligand complex [NN′-ethylenebis(salicylideneiminato)](acetylacetonato)cobalt( III )–0·7 water

The crystal and molecular structure of the title compound has been determined from three-dimensional X-ray diffraction data. The crystals are orthorhombic, space-group P212121, with a= 17·58, b= 13·47, c= 8·29 Å, Z= 4. The structure was solved by the heavy-atom method and refined by least-squares techniques to R 0·091 for 1028 reflections, the lowest R value being obtained with the water-content 0·7H2O per molecule. The co-ordination polyhedron of the cobalt atom is a distorted octahedron in which two cis-co-ordination sites are occupied by the acetylacetonato-group and the others by the quadridentate ligand in a non-planar conformation. Further investigations are reported on mixed-ligand complexes where a salen-type ligand assumes such a conformation and on binuclear cobalt complexes in which one quadridentate molecule acts as a bisbidentate ligand.