CRYSTAL AND MOLECULAR-STRUCTURE OF TRIS(1,3-DIPHENYLPROPANE-1,3-DIONATO)COBALT(III)

The title compound appeared to be isomorphous and isostructural to one of two polymorphs of the corresponding iron(III) complexes. The cryst als of the complex belong to the triclinic system, space group P1BAR. The cell dimensions are: a = 9.851(3) angstrom, b = 10.647(3) angstrom , c = 18.008(6) angstrom, alpha = 9 93.44(2)-degree, veta = 94.91(2)-d egrees, gamma = 107.14(2)-degrees, V = 179(1) angstrom-3, Z = 2, mu(Mo K(alpha)) = 0.52 mm-1, D(x) = 1.351 gcm-3. Data collection was made wi th Philips PW1100 (STOE upgraded) automatic diffractometer using MoK(a lpha) radiation. The structure was solved by the heavy-atom method and refined by least-squares techniques to a conventional R factor 0.034 for 2997 unique reflections. The structure is built up of discrete mol ecules separated by normal van der Waals distances. The cobalt atom co ordination is distorted octahedrally with an averaged Co-O bond length 1.833(3) angstrom. The rotational orientation of the terminal phenyl rings with regard to the plane of the chelate ring are dictated by bot h electronic and dominant steric effect.