SYNTHESIS AND STRUCTURE OF DIDYSPROSIUM COMPLEXES WITH A TETRAKETONE

Two novel didysprosium (Dy-2) complexes of henyl-3'-methyl-5'-pyrazolo ne-4')-1,5-pentanedione (H(2)L), Dy(2)L(3) . 2H(2)O and Dy(2)L(3) . 5D MF (DMF = dimethylformamide), have been synthesized. The crystal struc ture of Dy(2)L(3) . 5DMF was determined by X-ray diffraction. Crystals are triclinic, space group <P(1)over bar>, with a = 16.99(1), b = 17. 970(9), c = 18.28(1) Angstrom, alpha = 110.36(4), beta = 101.47(6), ga mma = 111.11(5)degrees, V = 4533(9) Angstrom(3), M(r) = 2017.91, Z = 2 , D-x = 1.48 g cm(-3), mu = 17.22 cm(-1), F(000) = 2056, R = 0.074 wit h 3804 reflections used in the refinement. In the complex, each L bond s two dysprosium atoms with its two beta-diketone groups. Two DMF solv ent molecules bond to each dysprosium ion. The coordination number of the two dysprosium ions is eight. The eight oxygen atoms around the dy sprosium ion make up a distorted square antiprism coordination polyhed ron. The resonance structures of coordinated beta-diketonates are also discussed. Different lanthanide ions may stabilize the specific struc ture.