X-RAY STRUCTURE-ANALYSIS OF THE COBALT(III) COMPLEX FORMED WITH THE AMBIDENTATE LIGAND 3-HYDROXYIMINOPENTANE-2,4-DIONE - PROOF FOR N,O-FAC-COORDINATION AND RESONANCE CHARGE DELOCALIZATION

The complex [Co(inaa)3] (inaa = anion of 3-hydroxyiminopentane-2,4-dione) crystallizes in the triclinic space group P1BAR with a = 1549.8(8), b = 1174.2(6), c = 1127.1(5) pm, alpha = 111.95(2), beta = 94.73(2) gamma = 90.71(2)-degrees and Z = 4. The three ambidentate ligands are attached to the Co through N and O atoms, forming five-membered chelate rings. The N3O3 set of donor atoms forms a distorted octahedron around the Co with the three N and O atoms being in a facial arrangement. The unit cell contains two pairs of enantiomers. The analysis of bond lengths points to strong resonance charge delocalization within the coordinated ligands.