Synthesis, structure and luminescent properties of lanthanide(III) polymeric complexes constructed by citric acid

Two novel coordination polymers, [Eu(citrate)(H2O)]n (1) and [Tb(citrate)(H2O)]n (2), were synthesized under the hydrothermal reaction of lanthanide oxide with citric acid and characterized by single-crystal X-ray diffraction analysis, IR and TGA. They are isostructural and display 2D compact layer structure. TGA measurements illustrate that they are stable up to 250 °C. The ultimate emission peak appears at 614 nm (5D0 → 7F2 transitions) for complex 1 and 543 nm (5D4 → 7F5 transitions) for complex 2, respectively.