Detection of Toxic Polychlorinated Biphenyls by Nanoporous Metal–Organic Frameworks

Abstract

As a class of persistent organic pollutants (POPs), polychlorinated biphenyls (PCBs) are highly hazardous to the ecosystem, and their effective and facile detection is of high importance. Herein, we present two nanoporous metal–organic frameworks (MOFs), (Me2NH2)­[In­(CPTTA)]·(DMF)1.5(H2O)3.5 (BUT-174) and (Et2NH2)­[In­(CPTTA)]·(DEF)­(H2O)3 (BUT-175), constructed by In3+ ions and the aromatic-rich tetratopic carboxylate ligands, 5′-(4-carboxylatophenyl)-[1,1′:3′,1″-terphenyl]-3,4′′,5-tricarboxylate (CPTTA4–), which exhibit highly efficient turn-down fluorescence response toward 12 PCBs, especially for three highly toxic non-ortho-substituted PCBs (PCB-77, -126, and -169) with the so-called “coplanar” molecular configuration in various solvents with the limits of detection (LODs) down to the ppb level owing to the inner filter effect between MOFs and PCBs. In addition, the MOFs show high sensing selectivity toward PCBs over many relevant interferents, including hexabromocyclododecane (HBCD), decabromodiphenyl oxide (DBDPO), perfluorobutanoic acid (PFBA), and perfluorooctanoic acid (PFOA), as well as good recyclability and stability. It is demonstrated by this work that structurally well-defined MOFs could be promising sensory materials for the detection of highly toxic PCBs in a facile way.

Synthesis and Structure of an Aqueous Stable Europium-Based Metal–Organic Framework with Ratiometric Fluorescence Sensing for Phosphate and Luminescence Quenching for Salicylaldehyde

“…Furthermore, the UV–Vis spectrum of SA overlaps with the solid-state fluorescence emission spectrum of Eu-MOF at 300 to 350 nm (Figure S13, SI), indicating that SA may affect the absorption of excitation energy, which leads to the occurrence of fluorescence quenching. In conclusion, the mechanism of the fluorescence quenching of SA may be a photo-induced electron transfer and competitive absorption mechanism. , …”

Hydrolytically Stable Luminescent Cationic MOF for Selective Detection of Toxic Organic Arsenic in Water

“…Upon excitation at 363 nm in solid phase (Figure S21), iMOF-12C showed an intense broad peak with emission maxima at 413 nm, which overlapped with the emission maxima of the ligand itself, attributed to the ligand-centered luminescence caused by ligand-to-ligand charge transfer (LLCT) (Figure S22). Also, a new peak arises at 435 nm, which may be due to the ligand-to-metal charge transfer (LMCT) …”

Samarium-Based Turn-Off Fluorescence Sensor for Sensitive and Selective Detection of Quinolinic Acid in Human Urine and Serum

“…The fluorescent sensors are a kind of luminescent materials, − suitable for rapid QA detection. , Coordination polymers (CPs) or metal–organic frameworks (MOFs) are one of the important material platforms for fluorescent sensors. − The metal nodes weave with organic linkers into highly ordered spatial structures, which integrate the advantages of both sides to obtain the desired luminescent properties in CPs or MOF materials. − The ligands as energy antennae undertake the roles of the spacers and receptors and the metal nodes as the fluorophores to fabricate fluorescent sensors. Furthermore, the wide selections of the ligands and the metal nodes make the search for a fluorescent sensor feasible.…”