SYNTHESIS AND MOLECULAR STRUCTURE OF TETRAAQUA [2,9 -DIFORMYL- 1,10 PHENANTHROLINE BIS (SEMICARBAZONE)] CERIUM(III) PERCHLORATE, [Ce(PHENSC(H O) ] (CLO )

The complex of Ce(III), [ Ce (PHENSC) (H 0) ] (C10 ) , was synthesized using the PHENSC, a hexadentate ligand,2,9-diformyl-1,lO- Phenanthroline bis (semicarbazone), and characterized by X-ray diffraction. The cerium atom has an unusual coordination number of ten involving six donor atoms of the planar ligand in the equatorial plane and four oxygen atoms from four axial water molecules. The complex crystallizes in the monoclinic space group P2,k with four molecules per unit cell. The unit cell dimensions are cz = 16.085(3), b = 12.229 (4), and c=15.436(4) ?with ?= 95.20 (2)? . The position of the cerium atom was determined by the heavy atom method and refined by least-squares techniques to a final R value (R = |?F| / ? | F | of 0.071 for the 3166 reflections used in the analysis. The coordination polyhedron is probably best described in terms of 1-6-3 polyhedron