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

Abstract

An aqueous stable europium-based metal−organic framework with properties of ratiometric fluorescence sensing, namely, {[(CH 3 ) 2 NH 2 ][Eu(TCPB)(H 2 O) 2 ]•DMF} n (Eu-MOF; H 4 TCPB = 1,2,4,5-tetrakis(4-carboxyphenyl)-benzene), was synthesized under solvothermal conditions and structurally characterized. Crystal structure analysis shows that Eu-MOF is a three-dimensional porous crystal, in which the Eu III ion is an eight-coordinate square inverse prism with eight oxygen atoms. Fluorescence measurements show that Eu-MOF exhibits characteristic emission of the Eu III ion and ligand. Eu-MOF displays good selectivity and sensitivity as a ratiometric fluorescence sensor for phosphate anions with a low detection limit in Tris−HCl buffer solution. Furthermore, Eu-MOF also has a good ability to identify salicylaldehyde through fluorescence quenching with a detection limit of 0.095 ppm. Therefore, it is an excellent fluorescent sensing material for phosphate and organic salicylaldehyde.

Two Chemorobust Cobalt(II) Organic Frameworks as High Sensitivity and Selectivity Sensors for Efficient Detection of 3-Nitrotyrosine Biomarker in Serum

“…Numerous studies have declared metal–organic frameworks (MOFs) showing great potential as sensors for detecting toxic heavy metal ions/anions, hazardous chemicals, volatile organic compounds (VOCs), or even bioactive molecules, which can be attributed to the unique structural features of various architectures, large specific surface area, and easily modified confined space. − It is noteworthy that MOF-based sensors displayed highly sensitive and rapid detection abilities in sensing nitro-containing analytes, from the aromatic explosives of trinitrotoluene (TNT)/picric acid (TNP) to the nitroimidazole/nitrofuran antibiotics, owing to the electron-withdrawing nitro groups. − From this point of view, designing efficient and sensitive MOF-based 3-NT sensors is technically feasible. Recently, Wang and co-workers designed two LMOFs through a mixed-ligands strategy and then evaluated their luminescence sensing performances in detecting 3-NT in water. , Biswas’s group also designed a water-stable HfMOF and used it for 3-NT sensing in HEPES solution .…”

Dual-Emitting Mixed-Lanthanide Metal–Organic Framework for Ratiometric and Quantitative Visual Detection of 2,6-Pyridine Dicarboxylic Acid

“…In recent years, various DPA detection methods have been reported, including electrochemistry, high-pressure liquid chromatography, surface-enhanced Raman spectroscopy, and so on. − However, shortcomings such as expensive equipment, time consumption, and complicated sample preparation limit their application. Compared with these methods, fluorescence sensing has attracted enormous interest due to its easy operation, high sensitivity, and fast response. − Previous studies have shown that dual-emitting probes perform better in chemical sensing through self-calibration compared to single-emitting systems. , Some interesting ratiometric fluorescent probes have been reported for DPA detection.…”

Pyrazine Functionalization in Eu-MOF for Exclusive Ratiometric Luminescence Sensing of PO43–

“…Metal–organic frameworks (MOFs), composed of metal ions/clusters and organic linkers, are a class of crystalline porous coordination polymers. − Owing to their tunable pore sizes, variable surface functions, and large surface areas, MOFs have drawn widespread attention from scientists around the world for the past decades, for example, in the field of luminescence sensing. ,, Lanthanum-based MOFs (Ln-MOFs) are deemed promising candidates for tracking trace amounts of analytes due to their exceptionally strong rare-earth-based luminescence. ,− The single-emission luminescence quenching (turn-off) and luminescence enhancing (turn-on) can be easily realized in Ln-MOFs. − However, compared to ratiometric luminescence sensing, single-emission luminescence sensing is highly susceptible to environmental interference, limiting the scope of its practical applications. More importantly, the self-calibration of ratiometric luminescence sensors can significantly promote selective detection and accuracy in fluctuating environments. , Thus, the development of Ln-MOFs with highly stable ratiometric luminescence for on-site real-time detection is desirable.…”

“…20−25 Owing to their tunable pore sizes, variable surface functions, and large surface areas, MOFs have drawn widespread attention from scientists around the world for the past decades, for example, in the field of luminescence sensing. 9,26,27 Lanthanum-based MOFs (Ln-MOFs) are deemed promising candidates for tracking trace amounts of analytes due to their exceptionally strong rare-earth-based luminescence. 9,26−28 The single-emission luminescence quenching (turn-off) and luminescence enhancing (turn-on) can be easily realized in Ln-MOFs.…”