A Postsynthetic Modified MOF Hybrid as Heterogeneous Photocatalyst for α‑Phenethyl Alcohol and Reusable Fluorescence Sensor

The recent discovery of lanthanide-based metal–organic frameworks (Ln-MOFs) offers the potential to extend the chemical sensing and catalysis capabilities of metal–organic frameworks (MOFs). Herein, a new europium functionalized material based on MIL-125­(Ti)-NH₂ is synthesized by covalent postsynthetic modification and shows photocatalytic oxidation properties of α-phenethyl alcohol, and their fluorescence quenching behaviors are investigated. The catalytic efficiency is tested by monitoring the photocatalytic oxidation of α-phenethyl alcohol under ultraviolet light irradiation. Furthermore, MIL-125­(Ti)-AM-Eu is developed as a fluorescence sensor integrated with its photocatalytic and luminescent properties. The MIL-125­(Ti)-AM-Eu is used for detecting α-phenethyl alcohol, which could be successfully oxidized to acetophenone by the catalyst, and the fluorescence of MIL-125­(Ti)-AM-Eu has changed accordingly

“One-Stone–Two-Birds” Modulation for Na₃ScF₆‑Based Novel Nanocrystals: Simultaneous Morphology Evolution and Luminescence Tuning

Control over the morphology, size, and crystallographic phase of nanocrystals (NCs) through impurity doping is central to the realization of their unprecedented or improved properties. Herein we present the “one-stone–two-birds” modulation including simultaneous modification of the morphology and tuning of the luminescence for Na₃ScF₆ based NCs via a simple doping strategy. Ce³⁺/Tb³⁺ codoped Na₃ScF₆ NCs with monoclinic structure and hexagonal nanoplate or nanorod morphology were obtained through a modified solvothermal method. The formation of monodisperse Na₃ScF₆-based NCs with diverse architectures closely correlates with the doping level of Tb³⁺. On the basis of the experimental results, the possible growth mechanism for nanoparticles is proposed. Under UV light excitation, Na₃ScF₆:Ce³⁺/Tb³⁺ samples exhibited characteristic emissions from both Ce³⁺ and Tb³⁺ ions. By proper variation of the amount of Tb³⁺ doping while maintaining Ce³⁺ concentration, the emission color tuned from blue to green accompanied by the shape evolution from hexagonal nanoplate to short nanorod. Furthermore, the higher quantum yield from the current nanostructures compared with those of a LaPO₄-based nanophosphor indicated that this scandium-containing sample is a promising green emission phosphor candidate for lighting and display applications

Numerical Recognition System and Ultrasensitive Fluorescence Sensing Platform for Al³⁺ and UO₂²⁺ Based on Ln (III)-Functionalized MOF-808 via Thiodiglycolic Acid Intermediates

Continuous accumulation of Al3+ in the human body and unintended leakage of UO22+ have posed a great threat to human health and the global environment; thus searching an efficient probe for the detection of Al3+ and UO22+ is of great importance. Herein, we designed and synthesized two hydrolytically stable Eu3+- and Tb3+-functionalized MOF materials Eu@MOF-808-TDA and Tb@MOF-808-TDA via thiodiglycolic acid (TDA) intermediates by the postsynthetic modification method. Among them, Tb@MOF-808-TDA was applied to construct numerical recognition systems of multiples of three and four by the combination of fluorescent signals, hierarchical cluster analysis, and logical gates. In addition, Tb@MOF-808-TDA exhibits good selectivity and sensitivity for the detection of Al3+ and UO22+. The detection limit is calculated to be 0.085 ppm for Al3+ and 0.082 ppm for UO22+ in aqueous solutions, which is lower than or close to that of latest reported Ln-MOFs. Moreover, the probe shows excellent hydrolytic stability and luminescence stability in the pH range of 4–11, further providing solid evidence for the practical application of Tb@MOF-808-TDA. More importantly, a mixed matrix hydrogel PVA-Tb@MOF-808-TDA was prepared to achieve the visual detection of Al3+, which broadens the potential in real-world sensing applications

Imparting Tunable and White-Light Luminescence to a Nanosized Metal–Organic Framework by Controlled Encapsulation of Lanthanide Cations

An alternative way was demonstrated to fabricate highly luminescent MOFs and white-light emitter by encapsulating lanthanide­(III) (Ln³⁺) cations into the channels of Al-MIL-53-COOH (<b>1</b>) nanocrystals. The framework can serve as both a host and an antenna for protecting and sensitizing the luminescence of the Ln³⁺ cations. PXRD, TEM, FTIR, TGA, and N₂ adsorption measurements were performed to determine the structure, thermal stability, and BET surface area of the obtained products. The Ln³⁺-incorporated nanocrystals show strong emission under UV-light irradiation, and their luminescent properties were systematically studied. In contrast to the essentially unchangeable luminescence of lanthanide-based MOF, the luminescence of Ln³⁺ @<b>1</b> allows design and tuning. The versatile luminescence, good thermal stability, nanometer size, and compatibility with aqueous condition reveal these materials may have potential applications in LED lamps, barcoded materials, and biological sensors. In addition, the thin films of Ln³⁺@<b>1</b> were prepared by chemical solution deposition (CSD) from their metastabilized colloidal solutions, which open the way to practical applications such as pellets and sensors for vapors

Trace Detection of Organophosphorus Chemical Warfare Agents in Wastewater and Plants by Luminescent UIO-67(Hf) and Evaluating the Bioaccumulation of Organophosphorus Chemical Warfare Agents

Organophosphorus chemical warfare agents (OPCWAs) are a group of organic pollutants characterized by high toxicity and chemical stability, and they are very difficult to be degraded. The trace quality of OPCWAs in water and food will cause great harm to the human body. Therefore, the detection of OPCWAs is a difficult challenge, which has become the research hotspot over the world. In this work, a Hf-based luminescent metal–organic framework (Eu@<b>1</b>) is prepared, and the reactivity of Hf₁₂ results in a methanephosphonic acid (MPA)-induced luminescence quenching and the charge transfer from MPA to Hf­(IV) and generated exciplexes which are responsible for this quenching effect. The excellent performance of Eu@<b>1</b> in the detection of MPA, with its finer selectivity, high sensitivity (LOD = 0.4 ppm), and large linear range (10^–7 to 10^–3 M), is encouraging for application in wastewater detection. Importantly, MPA is a pollutant that can be absorbed by plants and causes the bioaccumulation effect, and thus, the detection of MPA in real plant samples is a purposeful topic. Eu@<b>1</b> also achieved satisfactory results in actual plant sample testing, and the bioaccumulation of MPA in onions, turnips, and cabbages is determined via our sensor. This fabricated detector provides a feasible path for the detection of ppm-level OPCWAs in a complex environment, which will help humans to avoid OPCWA-contaminated foods