New complexes of heavy lanthanides with 4,4′-bipyridine and trichloroacetates

Novel mixed-ligand complexes with empirical formula Ln(4-bpy)(2)(CCl3COO)(3)center dot nH(2)O [where Ln(III) = Dy, Ho, Er, Tm, Yb, Lu; 4-bpy = 4,4'-bipyridine] were prepared and characterized by chemical and elemental analysis, infrared spectroscopy, and conductivity measurements (in methanol, dimethylformamide, and dimethyl sulfoxide). X-ray powder diffraction patterns indicate that the complexes are small crystalline compounds. IR spectra of complexes show that all carboxylate groups and 4-bpy are engaged in coordination of lanthanide ions. The thermal behavior of complexes was studied by means of TG, DTG, DTA techniques in the solid state under nonisothermal conditions in air atmosphere. During heating, the complexes decompose via intermediate products to the oxide Ln(2)O(3). The combined TG-FTIR technique was employed to study the decomposition pathway of the Ho(III) and Tm(III) complexes in flowing argon atmosphere.