Lanthanide metal–organic frameworks based on a 1,2,3-triazole-containing tricarboxylic acid ligand for luminescence sensing of metal ions and nitroaromatic compounds

Abstract

A series of novel 3D lanthanide metal–organic frameworks based on unsymmetrical 1,2,3-triazole-containing tricarboxylic acid ligand 5-[4-(4-carboxy-phenyl)-[1,2,3]triazol-1-yl]-isophthalic (H₃TAIP) has been synthesized under solvothermal conditions. The ligand was synthesized with diethyl-5-azidoisophthalate and 4-ethynyl-benzoic acid ethyl ester through the copper-catalyzed azide alkyne cycloaddition (CuAAC) reaction. Single-crystal X-ray diffraction analyses reveal that these metal–organic frameworks are isostructural. The structures are constructed by bi-nuclear lanthanide metal clusters and TAIP³⁻ ligands and possess flu-3,6-C2/c net with point symbol (4².6)₂(4⁴.6².8⁷.10²). We explore the luminescence properties of compound 1, which shows the characteristic emission of Tb³⁺ and exhibits selective detection of 4-nitrophenol and Fe³⁺ ions in ethanol solution over other nitroaromatic compounds and metal ions.