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, ErIIIand 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 REIIIions show distorted capped trigonal – prismatic geometry. The 2,5-tdc2−ligands connect four REIIIcenters, adopting (κ1– κ1) – (κ1– κ1) – μ4coordination 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 → 3F2for 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 SmIIIand4I13/2 → 4I15/2for 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.