Construction of a series of rare earth metal-organic frameworks supported by thiophenedicarboxylate linker: Synthesis, characterization, crystal structures and near-infrared/visible luminescence

Abstract

Six novel rare earth metal organic-frameworks with the general formula {[RE2(2,5-tdc)3(dmso)2]·H2O}n (RE=YIII, PrIII, NdIII, SmIII, ErIII and TmIII; 2,5-tdc2−=2,5-thiophenedicarboxylate anion; dmso=dimethylsulfoxide) were synthesized and their complete characterization, including single crystal X-ray diffraction, FTIR spectroscopy and thermal analysis (TG/DTA) are reported. Structure analysis reveals that REIII ions show distorted capped trigonal – prismatic geometry. The 2,5-tdc2− ligands connect four REIII centers, adopting (κ1 – κ1) – (κ1 – κ1) – μ4 coordination mode, generating an interesting 3D network with potential application for gas adsorption. Photophysical properties were studied using excitation/emission spectra and the photoluminescence data show the near infrared (NIR) and visible (Vis) emission with the characteristic transitions: 1D2→3F2 for PrIII, 4F3/2→4IJ (J=9/2, 11/2 and 13/2) for NdIII, 4G5/2→6HJ (J=5/2, 7/2, 9/2 and 11/2) for SmIII and 4I13/2→4I15/2 for ErIII. This study indicates that 2,5-tdc2− ligand is able to act as a sensitizer for emission in NIR and Vis region in these ions.