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

ABSTRACT

A series of L-di-2-thenoyltartaric acid lanthanide coordination polymers, namely, {[La2L3(CH3OH)6(H2O)]·CH3OH·H2O}n (1), {[Ln2L3(CH3OH)x(H2O)6−x]·aCH3OH·bH2O}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)2L3(CH3OH)2(H2O)4]·CH3OH·2.75H2O}n (5), {[(Eu0.051Tb0.406La0.543)2L3(CH3OH)2(H2O)4]·0.5CH3OH·2H2O}n (6), and {[(Eu0.068Tb0.363Gd0.569)2L3(CH3OH)3(H2O)3]·CH3OH·H2O}n (7), have been synthesized using facile reactions of H2L (H2L = L-di-2-thenoyltartaric acid) with LnCl3·6H2O under ambient temperature. X-ray crystallographic analysis reveals that complexes 1­4 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 Eu(3+) and Tb(3+) 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 5­7 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.