Synthesis and crystal structure of [Na(H2O)4][EuL4] · 0.775CH2Cl2 (HL = 1,3-bis(1,3-dimethyl-1H-pyrazol-4-yl)-1,3-propanedione)

[Na(H 2 O) 4 ][EuL 4 ] · 0.775CH 2 Cl 2 ( I ) has been synthesized by the reaction of Eu(NO 3 ) 3 · 6H 2 O with 1,3-bis(1,3-dimethyl-1H-pyrasol-4-yl)-1,3-propanedione (HL) in the presence of NaOH. Its crystal structure has been solved by X-ray diffraction analysis. Crystals are tetragonal; a = 16.2401(5) Å, c = 11.9113(4) Å, V = 3141.50(17) Å 3 , ρ calcd = 1.427 g/cm 3 , μ(Mo K α ) = 1.140 mm −1 , space group P 4/ n , Z = 2. The structural units forming a crystal of compound I are [EuL 4 ] − complex anions, [Na(H 2 O) 4 ] + cations, and CH 2 Cl 2 molecules. The coordination polyhedron of the Eu atom is an Archimedean antiprism formed by the O atoms of four bidentate chelate ligands L − .