Modular Construction of Multivariate Metal–Organic Frameworks for Luminescent Sensing

Metal-organic frameworks (MOFs) have played a pivotal role as rapid and effective luminescent sensing materials. Numerous MOFs with diverse characteristics have been meticulously designed for target analytes. Previous studies have highlighted the factors of spectral characteristics, energy levels, interaction forces, and sensor stabilities for the luminescent sensing performance in response to a specific analyte. This conventional "point-to-point" approach necessitates the matching of sensing materials to a specific analyte. Herein, we develop a modular MOF-based luminescent sensing platform by using a mixed-ligand strategy. A luminescent MOF Eu-FDA with 2,5-furandicarboxylic acid can serve as the foundational platform, with partial replacement by nine distinct hexacyclic isophthalic acids as the modules, respectively, to specifically accommodate different analytes with particular structures and properties. This substitution has been meticulously confirmed through single-crystal X-ray diffraction. Confronted with analytes possessing diverse structural or property characteristics, modular isophthalic acid derivatives can enhance the sensing capability to achieve heightened sensitivity.