Synthesis, thermal study and some properties of Gd(III), Tb(III), Dy(III) and Er(III) complexes with 4,4′-bipyridine and dibromoacetates

New complexes with formulae: Ln(4-bpy)(CBr2HCOO)3·3H2O (where Ln(III) = Gd, Tb, Dy) and Er(4-bpy)1.5(CBr2HCOO)3·3H2O, were prepared and characterized by chemical, elemental analysis and IR spectroscopy. The nature of metal–ligand coordination was studied. All of them are crystalline. Gd(III), Tb(III) and Dy(III) complexes are isostructural in one group. Conductivity studies (in methanol, dimethyloformamide and dimethylsulfoxide) were also discussed. The thermal properties of complexes in the solid state were studied using TG–DTG techniques under dynamic flowing air atmosphere. TG–MS system was used for Tb(III) (as an example of isostructural compound) and Er(III) complexes to analyze principal volatile thermal decomposition and fragmentation products evolved during pyrolysis in dynamic flowing air atmosphere.