Structures and luminescent properties of Sm(III) and Eu(III) coordination polymers with benzoate and phthalate

Two new lanthanide coordination polymers with mixed organic carboxylates ligands were synthesized by reacting Sm(III) or Eu(III) perchlorates with benzoic acid (Hbc) and phthalic acid (H2bdc) at 170 °C by hydrothermal method. The chemical formulas of the two complexes were [Sm(bc)(bdc)(H2O)3]n (1) and [Eu(bc)(bdc)(H2O)2]n (2). The two compounds were characterized by IR spectra, element analyses and X-ray powder diffraction. The crystal structures were determined by X-ray single crystal diffraction. Complexes 1 and 2 were both two-dimensional (2D) layered structure. The two complexes produced the characteristic f-f transition luminescence of Sm(III) or Eu(III) ion with the excitations of UV-rays. The lifetimes of excited states for 4G5/2 (Sm(III)-1) and 5D0 (Eu(III)-2) were 5.5μs and 0.345 ms. The PL (photoluminescence) absolute quantum yield (Фa) for 2 was 14% (λex = 297 nm).