Smart Tuning of Luminescent Lanthanide Coordination Polymer Gels for Stimuli-Responsive Emission Modulation,...

Luminescent coordination polymer gels (CPG) have received significant advancements in the field of supramolecular chemistry due to their stimuli-responsiveness and tunable processability, which allows them to be practical in the field of sensing, anticounterfeiting, and multimodal security systems. Herein, a triad of tunable Eu and Tb-based luminescent self-assembled CPGs has been synthesized using tetrapodal carboxylic-based imide-mediated linker N,N'-bis(5-isophthalic acid)-pyromellitic diimide (BIPD). Tuning Eu(III) and Tb(III) in a stoichiometry with the blue emissive ligand created a chameleon-like optical response under UV-light, ultimately resulting in the synthesis of white-light emitting materials. The obtained CPGs demonstrate considerable potential for anticounterfeiting applications, functioning effectively as security luminous inks that can be applied to various surfaces, along with their remarkable reversible sol-gel phase transitions. The synthesized Tb_BIPD xerogel exhibits notable selectivity and sensitivity for the detection of the oxoanion MnO₄ ^-, operating through a turn-off sensing mechanism and attaining a limit of detection (LOD) of 0.83 ppm.