Lanthanide–Organic Frameworks with Uncoordinated Lewis Base Sites: Tunable Luminescence, Antibiotic Detection, and Anticounterfeiting

Abstract

Several new isostructural lanthanide metal–organic frameworks (Ln-MOFs), {[Ln2(L)3DMA4]·2DMA} n (1-Ln, where Ln = Eu, Tb, or Eu x Tb1–x ), were first constructed via the solvothermal reactions of 4,6-di­(4-carboxyphenyl)­pyrimidine and Ln3+ ions. 1-Ln exhibits a 4-connected two-dimensional framework endowed with uncoordinated Lewis base sites. An exploration of luminescence sensing demonstrated 1-Eu can be used for the selectivity detection of dimetridazole and metronidazole antibiotics in other antibiotics, blood plasma, and urine, acting as an exceptional recyclable luminescent probe. More importantly, the luminescent inks of 1-Ln are invisible, color adjustable, and stabilized, which may greatly improve their anticounterfeiting applications.

Selective and Sensitive Recognition of Specific Types of Toxic Organic Pollutants with a Chemically Stable Highly Luminescent Porous Organic Polymer (POP)

“…This further facilitates the electron transfer process from the LUMO of IP POP -1 to the LUMO of NFT or NFZ and resulted in a quenching response (Figure S38). , A similar observation was found in the case of the pesticides, as among all of them, the LUMOs of CHPS and nitrofen were found to be the closest to the HOMO of IP POP -1 (Figure e and Figure S39), which enabled the electron transfer process selectively between CHPS or nitrofen and IP POP -1, further causing fluorescence quenching (Figures S40 and S41). Therefore, along with energy transfer, the PET process was found to be one of the prominent mechanisms behind the selective emission quenching of IP POP -1 by NFT, NFZ, CHPS, and nitrofen in water.…”

Rational Construction of Two Zn–Organic Frameworks for Selective Luminescent Sensing and Efficient CO2 Chemical Fixation

“…In addition, complex 1 remained the skeleton structure after a series of sensing tests by the PXRD analysis (Figure S5). According to the relevant literature report, − this possible quenching mechanism was further confirmed by the overlap between the UV–vis spectrum of Cr 2 O 7 2– and the excitation spectrum of 1 (Figure d). As a consequence, the energy of excited light was strongly absorbed by Cr 2 O 7 2– to reduce the energy transfer efficiency from ligands to metal ions, ultimately leading to the luminescence quenching performance.…”

“…Meanwhile, the quenching effect of 2 toward Cr 2 O 7 2– was studied in the presence of different interfering anions, and only Cr 2 O 7 2– could cause the luminescence quenching performance of 2 (Figure c). The overlap between the UV–vis spectrum of Cr 2 O 7 2– in water and the excitation spectrum of 2 shows that the quenching performance was caused by the competitive absorption of Cr 2 O 7 2– and 2 as the above-mentioned quenching mechanism (Figure d). − In addition, PXRD patterns confirmed the fine stability of 2 during the sensing process in different anions (Figure S8). As a result, both composites have highly selective and sensitive detectability toward Cr 2 O 7 2– in water.…”

A pH-Stable TbIII-Based Metal–Organic Framework as a Turn-On and Blue-Shift Fluorescence Sensor toward Benzaldehyde and Salicylaldehyde in Aqueous Solution

“…Lanthanide metal–organic frameworks (Ln-MOFs) with abundant spatial structures and tunable pore sizes have been extensively studied in chemical sensing, , light-emitting diode (LED) lighting, catalysis, , and gas storage/separation. − Ln-MOFs not only have excellent luminescent properties and high selectivity but also exhibit a variety of sensing objects, such as organic pollutants, metal ions, anion, medicine, etc . However, the limited water stability of most Ln-MOFs hinders practical application in aqueous media environments.…”