A metal–organic framework featuring highly sensitive fluorescence sensing for Al3+ ions

Abstract

High sensitivity and selectivity for the detection of metal ions are very important to protect human health. Fluorescent metal–organic frameworks (MOFs) as new sensing materials have attracted more and more attention. Herein, a pillar-layered fluorescent metal–organic framework, {[H₂N(CH₃)₂]₂[Cd₅(TCPE)₃(4,4′-bpy)₂(MeOH)₂(H₂O)₄]}_n (NKM-102) (H₄TCPE = tetrakis(4-carboxyphenyl)ethylene acids, 4,4′-bpy = 4,4′-bipyridine), has been synthesized through utilization of the H₄TCPE ligand with typical AIE characteristics. NKM-102 exhibits excellent fluorescence emission performance and detects Al³⁺ ions with high selectivity through turn-off effect and emission color change. Moreover, the detection limit of NKM-102 can reach 158 ppb, which is lower than the maximum limit of Al³⁺ ions in drinking water recommended by the United States Environmental Protection Agency (200 ppb). Therefore, the NKM-102 probe is a prominent candidate for the visual detection of Al³⁺ ions with high sensitivity and selectivity.