Crystal structure and luminescence of (4,4′-dimethyl-2,2′-bipyridine)-tris(benzoate)europium(III)

A mixed ligand europium complex, [Eu(BA)(3)dmbpy](2), has been prepared, where BA = benzoate and dmbpy = 4,4'-dimethyl-2,2'-bipyridine. The complex crystallizes in the triclinic system, space group P-1(-). Its structure has been determined using X-ray diffraction methods. The two europium ions In the molecule are held together by four carboxylate groups of benzoic acid and each europium ion is further bonded to one bidentate carboxylate group and one 4,4'-dimethyl-2,2'-bipyridine molecule. Excitation and luminescence spectra observed at 77 K show that the europium site in the crystal has low symmetry and changes of the chemical surroundings of the europium ion in the molecule depend mainly on the flexibility of 4,4'-dimethyl-2,2'-bibyridine.