Synthesis, Photoluminescence and Effect of Lanthanide Contraction on Structures of 3D Lanthanide‐Organic Frameworks from 1,4‐Benzenedicarboxylic Acid and Oxalic Acid

Abstract

AbstractSix new 3D lanthanide‐based organic frameworks with the formula of [Ln2(1,4‐BDC)2(ox)(H2O)4]⋅2H2O (Ln=Tb 1, Dy 2, Gd 3) and [Ln2(1,4‐BDC)2(ox)(H2O)2] (Ln=Ho 4, Er 5, Yb 6; 1,4‐H2BDC=1,4‐benzenedicarboxylate; H2ox=oxalate acid) were synthesized by hydrothermal method and characterized by elemental analysis, IR spectra, UV–vis spectra, powder X‐ray diffraction, and TG‐DTA method, wherein compounds 1 and 4 were structurally characterized. Compounds 1–3 had been found to be isostructural and crystallized in the monoclinic crystal system with space group of P21/c possessing quasi‐square 1D channels wherein lattice water molecules were encapsulated, while the isostructural compounds 4–6 crystallized in triclinic system with P‐1 space group, while their triangular 1D channels are too small to encapsulate any solvent molecules. The significant lanthanide contraction effect is evident from the observed resulting structures of compounds 1–6 which were synthesized under the same reaction conditions. Compounds 1 and 2 exhibited characteristic emissions of Tb(III) and Dy(III) ions and the luminescent lifetime of compound 1 was found to be 0.54 ms.