Synthesis and structure of didysprosium complexes with a tetraketone

Two novel didysprosium (Dy-2) complexes of 1,5-bis(1'-phenyl-3'-methyl-5'-pyrazolone-4')-1,5-pentanedione (H(2)L), Dy(2)L(3) . 2H(2)O and Dy(2)L(3) . 5DMF (DMF = dimethylformamide), have been synthesized. The crystal structure 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), gamma = 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 with 3804 reflections used in the refinement. In the complex, each L bonds two dysprosium atoms with its two beta-diketone groups. Two DMF solvent molecules bond to each dysprosium ion. The coordination number of the two dysprosium ions is eight. The eight oxygen atoms around the dysprosium ion make up a distorted square antiprism coordination polyhedron. The resonance structures of coordinated beta-diketonates are also discussed. Different lanthanide ions may stabilize the specific structure.