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Efficient adsorption of palladium ions from acid nuclear waste solution is crucial for ensuring the safety of vitrification process for radioactive waste. However, the limited stability and selectivity of most current adsorbents hinder their practical applications under strong acid and intense radiation conditions. Herein, to address these limitations, we designed and synthesized an aryl‐ether‐linked covalent organic framework (COF‐316‐DM) grafted dimethylthiocarbamoyl groups on the pore walls. This unique structure endows COF‐316‐DM with high stability and exceptional palladium capture capacity. The robust polyarylether linkage enables COF‐316‐DM to withstand irradiation doses of 200 or 400 kGy of β/γ ray. Furthermore, COF‐316‐DM demonstrates fast adsorption kinetics, high adsorption capacity (147 mg g−1), and excellent reusability in 4 M nitric acid. Moreover, COF‐316‐DM exhibits remarkable selectivity for palladium ions in the presence of 17 interference ions, simulating high level liquid waste scenario. The superior adsorption performance can be attributed to the strong binding affinity between the thioamide groups and Pd2+ ions, as confirmed by the comprehensive analysis of FT‐IR and XPS spectra. Our findings highlight the potential of COFs with robust linkers and tailored functional groups for efficient and selective capture of metal ions, even in harsh environmental conditions. [ABSTRACT FROM AUTHOR]

Low‐valent uranium‐element multiple bond complexes remain scarce, though there is burgeoning interest regarding to their bonding and reactivity. Herein, isolation of a uranium(III)‐carbon double bond complex [(Cp*)2U(CDP)](BPh4) (1) comprising a tridentate carbodiphosphorane (CDP) was reported for the first time. Oxidation of 1 afforded the corresponding U(IV) complex [(Cp*)2U(CDP)](BPh4)2 (2). The distance between U and C in 2 is 2.481 Å, indicating the existence of a typical U=C double bond, which is further confirmed by quantum chemical calculations. Bonding analysis suggested that the CDP also serves as both σ‐ and π‐donor in complex 1, though a longer U−C bond (2.666(3) Å) is observed. It implies that 1 is the first isolable mononuclear uranium(III) carbene complex. Moreover, these results suggest that CDPs are promising ligands to establish other low‐valent f‐block metal‐carbon multiple bond complexes. [ABSTRACT FROM AUTHOR]

As one of most problematic radionuclides, technetium‐99, mainly in the form of anionic pertechnetate (TcO4−), exhibits high environmental mobility, long half‐life, and radioactive hazard. Due to low charge density and high hydrophobicity for this tetrahedral anion, it is extremely difficult to recognize it in water. Seeking efficient and selective recognition method for TcO4− is still a big challenge. Herein, a new water‐stable cationic metal‐organic framework (ZJU‐X8) was reported, bearing tetraphenylethylene pyrimidine‐based aggregation‐induced emission (AIE) ligands and attainable silver sites for TcO4− detection. ZJU‐X8 underwent an obvious spectroscopic change from brilliant blue to flavovirens and exhibited splendid selectivity towards TcO4−. This uncommon fluorescent recognition mechanism was well elucidated by batch sorption experiments and DFT calculations. It was found that only TcO4− could enter into the body of ZJU‐X8 through anion exchange whereas other competing anions were excluded outside. Subsequently, after interaction between TcO4− and silver ions, the electron polarizations from pyrimidine rings to Ag+ cations significantly lowered the energy level of the π* orbital and thus reduced the π–π* energy gap, resulting in a red‐shift in the fluorescent spectra. [ABSTRACT FROM AUTHOR]

Scintillators are a unique class of luminescent materials with specific applications towards radiation detection. The emitters within state‐of‐the‐art scintillators are mostly limited to bismuth, cerium, europium, thallium, lead, tungsten, etc. A shared feature of these elements is the relatively high atomic number, which is responsible for high radiation stopping power and radiation‐induced luminescence. Searching for new scintillating materials is an essential target aiming at specific applications. In this Concept article, we will discuss our recent works on the topic of "uranyl‐bearing scintillators". As a virgin territory in this field, uranyl‐bearing scintillators show intrinsic merits for designing new materials with X‐ray detection capability, that is, the large photoelectric cross‐section, high X‐ray attenuation efficiency, and high crystal density. In addition, we also present challenges in the further development of the uranyl‐bearing scintillators. [ABSTRACT FROM AUTHOR]

Designability is an attractive feature for metal–organic frameworks (MOFs) and essential for reticular chemistry, and many ideas are significantly useful in the carboxylate system. Bi‐, tri‐, and tetra‐topic phosphonate ligands are used to achieve framework structures. However, an efficient method for designing phosphonate MOFs is still on the way, especially for uranyl phosphonates, owing to the complicated coordination modes of the phosphonate group. Uranyl phosphonates prefer layer or pillar‐layered structures as the topology extension for uranyl units occurs in the plane perpendicular to the linear uranium‐oxo bonds and phosphonate ligands favor the formation of compact structures. Therefore, an approach that can construct three‐dimensional (3D) uranyl phosphonate MOFs is desired. In this paper, a sterically hindered phosphonate ligand method (SHPL) is described and is successfully used to achieve 3D framework structures of uranyl phosphonates. Four MOF compounds ([AMIM]2(UO2)(TppmH4)⋅H2O (UPF‐101), [BMMIM]2(UO2)3(TppmH4)2⋅H2O (UPF‐102), [Py14]2(UO2)3(TppmH4)2⋅3 H2O (UPF‐103), and [BMIM](UO2)3(TppmH3)F2⋅2 H2O (UPF‐104); [AMIM]=1‐allyl‐3‐methylimidazolium, [BMMIM]=1‐butyl‐2,3‐dimethylimidazolium, [Py14]=N‐butyl‐N‐methylpyrrolidinium, and [BMIM]=1‐butyl‐3‐methylimidazolium) are obtained by ionothermal synthesis, with zero‐dimensional nodes of uranyl phosphonates linked by steric tetra‐topic ligands, namely tetrakis[4‐(dihyroxyphosphoryl)phenyl]methane (TppmH8), to give 3D framework structures. Characterization by PXRD, UV/Vis, IR, Raman spectroscopy, and thermogravimetry (TG) were also performed. [ABSTRACT FROM AUTHOR]

It is shown that UVO2+ ions can reside at UVIO22+ lattice sites during mild reduction and crystallization process under solvothermal conditions, yielding a complicated and rare mixed-valent uranium phosphonate compound that simultaneously contains UIV, UV, and UVI. The presence of uranium with three oxidation states was confirmed by various characterization techniques, including X-ray crystallography, X-ray photoelectron, electron paramagnetic resonance, FTIR, UV/Vis-NIR absorption, and synchrotron radiation X-ray absorption spectroscopy, and magnetism measurements. [ABSTRACT FROM AUTHOR]

Cooperative performance of mixed-valent Eu2+/Eu3+ in single-compound phosphors offers significant advantages in color rendering and luminescence efficiency, but their synthesis is challenging because of Eu2+ oxidation. Using the tunable nature of the metal-ion nodes in metal-organic frameworks (MOFs), we present an in situ reduction and crystallization route for preparing MOFs and doping Eu2+/Eu3+ with a controlled ratio. These materials exhibit rich photoluminescence, including intrinsic- and sensitized-emissions of Eu2+ and Eu3+, and long-lived luminescence from charge transfer. Color rendering can be easily achieved by fine-tuning the valence states of Eu. A linear relation between temperature and the intensity ratio of Eu2+/Eu3+ emissions provides outstanding properties for applications as self-calibrated luminescent thermometers with a wide working temperature range. Further incorporation of Tb3+ into the MOFs results in white light, utilizing all Eu2+,Tb3+, and Eu3+ emissions in a single crystalline lattice. [ABSTRACT FROM AUTHOR]

The limited long-term hydrolytic stability of rapidly emerging 3D-extended framework materials (MOFs, COFs, MOPs, etc.) is still one of major barriers for their practical applications as new solid-state electrolytes in fuel cells. To obtain hydrolytically stable materials, two H2PO4−-exchanged 3D inorganic cationic extended frameworks (CEFs) were successfully prepared by a facile anion-exchange method. Both anion-exchanged CEFs (YbO(OH)P and NDTBP) show significantly enhanced proton conductivity when compared with the original materials (YbO(OH)Cl and NDTB) with an increase of up to four orders-of-magnitude, reaching 2.36×10−3 and 1.96×10−2 S cm−1 at 98 % RH and 85 °C for YbO(OH)P and NDTBP, respectively. These values are comparable to the most efficient proton-conducting MOFs. In addition, these two anion-exchanged materials are stable in boiling water, which originates from the strong electrostatic interaction between the H2PO4− anion and the cationic host framework, showing a clear advance over all the acid-impregnated materials (H2SO4@MIL-101, H3PO4@MIL-101, and H3PO4@Tp-Azo) as practical solid-state fuel-cell electrolytes. This work offers a new general and efficient approach to functionalize 3D-extended frameworks through an anion-exchange process and achieves water-stability with ultra-high proton conductivity above 10−2 S cm−1. [ABSTRACT FROM AUTHOR]

Keywords: luminescence; radiation detection; scintillators; uranium As a new area in this field, uranyl-bearing scintillators show intrinsic merits for designing new materials with X-ray detection capability, that is, a large photoelectric cross-section, high X-ray attenuation efficiency, and high crystal density. Luminescence, radiation detection, scintillators, uranium. [Extracted from the article]

It is shown that UVO2+ ions can reside at UVIO22+ lattice sites during mild reduction and crystallization process under solvothermal conditions, yielding a complicated and rare mixed-valent uranium phosphonate compound that simultaneously contains UIV, UV, and UVI. The presence of uranium with three oxidation states was confirmed by various characterization techniques, including X-ray crystallography, X-ray photoelectron, electron paramagnetic resonance, FTIR, UV/Vis-NIR absorption, and synchrotron radiation X-ray absorption spectroscopy, and magnetism measurements. [ABSTRACT FROM AUTHOR]