Ultrasound-Assisted Synthesis of Luminescent Micro- and Nanocrystalline Eu-Based MOFs as Luminescent Probes for Heavy Metal Ions

• Published in: Nanomaterials (Basel, Switzerland) Vol. 11; no. 9; p. 2448
• Main Authors: Kolesnik, Stefaniia S., Nosov, Viktor G., Kolesnikov, Ilya E., Khairullina, Evgenia M., Tumkin, Ilya I., Vidyakina, Aleksandra A., Sysoeva, Alevtina A., Ryazantsev, Mikhail N., Panov, Maxim S., Khripun, Vasiliy D., Bogachev, Nikita A., Skripkin, Mikhail Yu, Mereshchenko, Andrey S.
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 20.09.2021; MDPI
• Subjects: Aqueous solutions; Caustic soda; Chemical synthesis; Chloride; Copper; Crystals; Drinking water; Electron micrographs; Emissions; Europium; Experiments; Heavy metals; Iron; Light scattering; Luminescence; Luminescence quenching; luminescent probe; Metal ions; metal-organic framework; Metal-organic frameworks; Microparticles; Nanocrystals; nanoparticle; Nanoparticles; Particle size; Photon correlation spectroscopy; Polyethylene glycol; Probes; Quantum efficiency; Radiation; rare earth; Rare earth elements; Rate constants; Reagents; Scanning electron microscopy; Sensors; Size reduction; Spectrum analysis; Surfactants; Terephthalate; Ultrasonic testing; Ultrasound; Japan; Germany
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano11092448

The luminescent coarse-, micro- and nanocrystalline europium(III) terephthalate tetrahydrate (Eu2bdc3·4H2O) metal-organic frameworks were synthesized by the ultrasound-assisted wet-chemical method. Electron micrographs show that the europium(III) terephthalate microparticles are 7 μm long leaf-like plates. According to the dynamic light scattering technique, the average size of the Eu2bdc3·4H2O nanoparticles is equal to about 8 ± 2 nm. Thereby, the reported Eu2bdc3·4H2O nanoparticles are the smallest nanosized rare-earth-based MOF crystals, to the best of our knowledge. The synthesized materials demonstrate red emission due to the 5D0–7FJ transitions of Eu3+ upon 250 nm excitation into 1ππ* state of the terephthalate ion. Size reduction results in broadened emission bands, an increase in the non-radiative rate constants and a decrease in both the quantum efficiency of the 5D0 level and Eu3+ and the luminescence quantum yields. Cu2+, Cr3+, and Fe3+ ions efficiently and selectively quench the luminescence of nanocrystalline europium(III) terephthalate, which makes it a prospective material for luminescent probes to monitor these ions in waste and drinking water.