Influence of halide ions on the chirality and luminescent property of ionothermally synthesized lanthanide-based metal–organic frameworks

Abstract

Four lanthanide-based metal–organic frameworks, [Emim][Ln_1.5(2,5-tdc)₂]Cl_1.5−xBr_x (Ln = Nd 1, Eu 2) and [Emim][Ln(2,5-tdc)₂] (Ln = Nd 3, Eu 4) (2,5-tdc = thiophene-2,5-dicarboxylate, Emim = 1-methyl-3-ethylimidazolium), were synthesized under ionothermal conditions. Compounds 1 and 2 crystallize in the polar space groupP2₁2₁2, while 3 and 4 crystallize in the central symmetry space groupP2₁/c. Luminescence studies revealed a significantly higher quantum yield of 4 than that of 2, with similar lifetimes. It is clear that the coordination of the halide ions has profound effects on the structures and properties of these lanthanide-based metal–organic frameworks.