Color-tunable and white-light emission of one-dimensional L-di-2-thenoyltartaric acid mixed-lanthanide coordination polymers

摘要

A series of L-di-2-thenoyltartaric acid lanthanide coordination polymers, namely, {[La2L3(CH3OH) (6)(H2O)]center dot CH3OH center dot H2O}(n) (1), {[Ln(2)L(3)(CH3OH)(x)(H2O)(6-x)]center dot aCH(3)OH center dot bH(2)O}(n), [Ln = Eu (2), x = 2, a = 0.5, b = 0.25; Ln = Gd (3), x = 3, a = 1, b = 0; Ln = Tb (4), x = 2, a = 1, b = 0], {[(Eu0.037Tb0.963)(2)L-3(CH3OH)(2)(H2O)(4)]center dot CH3OH center dot 2.75H(2)O}(n) (5), {[(Eu0.051Tb0.406La0.543)(2)L-3(CH3OH)(2)(H2O)(4)]center dot 0.5CH(3)OH center dot 2H(2)O}(n) (6), and {[(Eu0.068Tb0.363Gd0.569)(2)L-3(CH3OH)(3)(H2O)(3)]center dot CH3OH center dot H2O}(n) (7), have been synthesized using facile reactions of H2L (H2L = L-di-2-thenoyltartaric acid) with LnCl(3)center dot 6H(2)O under ambient temperature. X-ray crystallographic analysis reveals that complexes 1-4 are isostructural, featuring one-dimensional (1D) ladder-like chain structures, in which the Ln(3+) ions are bridged by the carboxylate groups of the ligands. The luminescent spectra in the solid state at room temperature reveal that complexes 2 and 4 exhibit the characteristic red and green luminescence of Eu3+ and Tb3+ ions, respectively, whereas complexes 1 and 3 display the blue emission of the ligand with a broad band centered at 422 nm. Notably, the mixed-lanthanide coordination polymers 5-7 exhibit color-tunable luminescence from yellow and white to blue upon variation of the excitation wavelength. It realizes color-tunable and white-light emission in 1D carboxylic acid mixed-lanthanide coordination polymers.