A 3,2-Hydroxypyridinone-based Decorporation Agent that Removes Uranium from Bones In Vivo.

Searching for actinide decorporation agents with advantages of high decorporation efficiency, minimal biological toxicity, and high oral efficiency is crucial for nuclear safety and the sustainable development of nuclear energy. Removing actinides deposited in bones after intake is one of the most significant challenges remaining in this field because of the instantaneous formation of highly stable actinide phosphate complexes upon contact with hydroxyapatite. Here we report a hydroxypyridinone-based ligand (5LIO-1-Cm-3,2-HOPO) exhibiting stronger affinity for U(VI) compared with the reported tetradentate hydroxypyridinone ligands.

Efficient and selective sensing of Cu and UO by a europium metal-organic framework.

We report here the investigation of using a luminescent europium organic framework, [Eu(MTBC)(OH)(DMF)(HO)]·2DMF·7HO (denoted as compound 1), for detecting of both Cu and UO with high sensitivity. Based on the spectroscopy analysis, compound 1 could selectively respond to Cu and UO ions among other selected monovalent, divalent, trivalent metal cations based on a turn-off mechanism. The detection limit of compound 1 towards Cu ion was as low as 17.

Anionic uranyl oxyfluorides as a bifunctional platform for highly selective ion-exchange and photocatalytic degradation of organic dyes.

Uranium is unique owing not only to its intriguing physiochemical properties, but also to the diverse coordination chemistry that uranyl adopts and bonding that enables rich and unpredictable topologies of uranium-bearing materials. Six anionic uranium oxyfluorides with various dimensionalities, including a 3D framework (MeUF), four 2D lamellar structures (EtUF-1, PrUF, BuUF-1, and BuUF-2), and a 1D chained topology (EtUF-2), have been rationally constructed by employing tetra-alkyl ammonium ions as structure-directing agents. By combining the tunable interlayer distance of the lamellar structures with the photooxygenation properties of uranyl ions, a bifunctional platform for highly selective ion-exchange and photocatalytic degradation over organic dyes has been developed.

TcO remediation by a cationic polymeric network.

Direct removal of TcO from the highly acidic solution of used nuclear fuel is highly beneficial for the recovery of uranium and plutonium and more importantly aids in the elimination of Tc discharge into the environment. However, this task represents a huge challenge given the combined extreme conditions of super acidity, high ionic strength, and strong radiation field. Here we overcome this challenge using a cationic polymeric network with significant TcO uptake capabilities in four aspects: the fastest sorption kinetics, the highest sorption capacity, the most promising uptake performance from highly acidic solutions, and excellent radiation-resistance and hydrolytic stability among all anion sorbent materials reported.

Monitoring Ultraviolet Radiation Dosage Based on a Luminescent Lanthanide Metal-Organic Framework.

A luminescent lanthanide metal-organic framework [Tb(OH)(HO)(IDA)(COO)]·4Cl·2HO (Tb-IDA, IDA = iminodiacetic acid) was hydrothermally synthesized and structurally characterized. Monitoring ultraviolet radiation was achieved by correlating the dosage with the luminescence color change in doped GdTbEu-IDA compound. A linear relationship is developed across a broad range from blue to yellow within a CIE chromaticity diagram.

Structural and thermodynamic stability of uranyl-deferiprone complexes and the removal efficacy of U(vi) at the cellular level.

Deferiprone (3-hydroxy-1,2-dimethyl-4(1H)-pyridone, DFP), which is a drug clinically used for removing heavy metals in vivo, was explored for its removal efficiency towards uranium. The reaction of uranyl nitrate hexahydrate with DFP at room temperature yielded the compound [(UO2)(H2O)(C7NO2H8)2]·4H2O (1), which crystallizes from a mixed solution of methanol and water (pH = 7.0).

Immobilization of Alkali Metal Fluorides via Recrystallization in a Cationic Lamellar Material, [Th(MoO)(HO)Cl]Cl·HO.

Searching for cationic extended materials with a capacity for anion exchange resulted in a unique thorium molybdate chloride (TMC) with the formula of [Th(MoO)(HO)Cl]Cl·HO. The structure of TMC is composed of zigzagging cationic layers [Th(MoO)(HO)Cl] with Cl as interlamellar charge-balancing anions. Instead of performing ion exchange, alkali thorium fluorides were formed after soaking TMC in AF (A = Na, K, and Cs) solutions.

In Situ Reduction from Uranyl Ion into a Tetravalent Uranium Trimer and Hexamer Featuring Ion-Exchange Properties and the Alexandrite Effect.

By utilizing zinc amalgam as an in situ reductant and pH regulator, mild hydrothermal reaction between UO(CHCOO)·2HO, HSO, and CsCO or between UO(CHCOO)·2HO, CH(SOH), and KCO yielded a novel cesium U sulfate trimer Cs[UO(SO)]·2.2HO (1) and a new potassium U disulfonic hexamer K[UO(OH)(HO)][CH(SO)]·6HO (2), respectively. Compound 1 features a lamellar structure with a honeycomb lattice, and it represents an unprecedented trimeric U cluster composed of purely inorganic moieties.

Covalent Organic Framework Functionalized with 8-Hydroxyquinoline as a Dual-Mode Fluorescent and Colorimetric pH Sensor.

Real-time and accurate detection of pH in aqueous solution is of great significance in chemical, environmental, and engineering-related fields. We report here the use of 8-hydroxyquinoline-functionalized covalent organic framework (COF-HQ) for dual-mode pH sensing. In the fluorescent mode, the emission intensity of COF-HQ weakened as the pH decreased, and also displayed a good linear relationship against pH in the range from 1 to 5.

Unique Proton Transportation Pathway in a Robust Inorganic Coordination Polymer Leading to Intrinsically High and Sustainable Anhydrous Proton Conductivity.

Although comprehensive progress has been made in the area of coordination polymer (CP)/metal-organic framework (MOF)-based proton-conducting materials over the past decade, searching for a CP/MOF with stable, intrinsic, high anhydrous proton conductivity that can be directly used as a practical electrolyte in an intermediate-temperature proton-exchange membrane fuel cell assembly for durable power generation remains a substantial challenge. Here, we introduce a new proton-conducting CP, (NH)[Zr(HPO)] (ZrP), which consists of one-dimensional zirconium phosphate anionic chains and fully ordered charge-balancing NH cations. X-ray crystallography, neutron powder diffraction, and variable-temperature solid-state NMR spectroscopy suggest that protons are disordered within an inherent hydrogen-bonded infinite chain of acid-base pairs (N-H···O-P), leading to a stable anhydrous proton conductivity of 1.

Superprotonic conduction through one-dimensional ordered alkali metal ion chains in a lanthanide-organic framework.

Although no evident hydrogen-bond network appears, an ultrahigh proton conductivity of 2.91 × 10-2 S cm-1 at 363 K and 90% RH with an ultralow activation energy of 0.10 eV was observed in an anionic lanthanide-organic framework Na2[Eu(SDB)2(COO)]·0.

Employing an Unsaturated Th Site in a Porous Thorium-Organic Framework for Kr/Xe Uptake and Separation.

Actinide based metal-organic frameworks (MOFs) are unique not only because compared to the transition-metal and lanthanide systems they are substantially less explored, but also owing to the uniqueness of actinide ions in bonding and coordination. Now a 3D thorium-organic framework (SCU-11) contains a series of cages with an effective size of ca. 21×24 Å.

Emergence of Uranium as a Distinct Metal Center for Building Intrinsic X-ray Scintillators.

The combination of high atomic number and high oxidation state in U materials gives rise to both high X-ray attenuation efficiency and intense green luminescence originating from ligand-to-metal charge transfer. These two features suggest that U materials might act as superior X-ray scintillators, but this postulate has remained substantially untested. Now the first observation of intense X-ray scintillation in a uranyl-organic framework (SCU-9) that is observable by the naked eye is reported.

A Large Family of Centrosymmetric and Chiral f-Element-Bearing Iodate Selenates Exhibiting Coordination Number and Dimensional Reductions.

The exploration of phase formation in the f-element-bearing iodate selenate system has resulted in 14 novel rare-earth-containing iodate selenates, Ln(IO)(SeO) (Ln = La, Ce, Pr, Nd; LnISeO-1), Ln(IO)(SeO)(HO) (Ln = Sm, Eu; LnISeO-2), and Ln(IO)(SeO)(HO)·HO (Ln = Gd, Dy, Ho, Er, Tm, Yb, Lu, Y; LnISeO-3), as well as two new thorium iodate selenates, Th(OH)(IO)(SeO)(HO) (ThISeO-1) and Th(IO)(SeO) (ThISeO-2). LnISeO-3 and ThISeO-2 crystallize in the chiral space group P222, while LnISeO-1, LnISeO-2, and ThISeO-1 crystallize in the centrosymmetric space group P2/c. The numbers of both coordinating and hydrating water molecules crystallized in LnISeO-1, LnISeO-2, and LnISeO-3 increase along these three series, in line with the increasingly negative values of hydration enthalpies of heavier trivalent lanthanide ions.

An Ultrastable Heterobimetallic Uranium(IV)/Vanadium(III) Solid Compound Protected by a Redox-Active Phosphite Ligand: Crystal Structure, Oxidative Dissolution, and First-Principles Simulation.

The first heterobimetallic uranium(IV)/vanadium(III) phosphite compound, NaUV(HPO) (denoted as UVP), was synthesized via an in situ redox-active hydrothermal reaction. It exhibits superior hydrolytic and antioxidant stability compared to the majority of structures containing low-valent uranium or vanadium, further elucidated by first-principles simulations, and therefore shows potential applications in nuclear waste management.

Highly Sensitive Detection of UV Radiation Using a Uranium Coordination Polymer.

The accurate detection of UV radiation is required in a wide range of chemical industries and environmental or biological related applications. Conventional methods taking advantage of semiconductor photodetectors suffer from several drawbacks such as sophisticated synthesis and manufacturing procedure, not being able to measure the accumulated UV dosage as well as high defect density in the material. Searching for new strategies or materials serving as precise UV dosage sensor with extremely low detection limit is still highly desirable.

Phase transition triggered aggregation-induced emission in a photoluminescent uranyl-organic framework.

When exposed to water, the two-dimensional uranyl-organic layered compound [(CH)NH][(UO)(BCPBA)]·2DMF·HO (HBCPBA = 3,5-bis (4'-carboxylphenoxy) benzoic acid) gradually undergoes a complete single-crystal-to-single-crystal phase transition to [(CH)NH][(UO)(BCPBA)]·3.4HO, resulting in an enhanced ligand-ligand interaction between the adjacent layers. This process gives rise to initial quenching of the uranyl photoluminescence followed by subsequent recovery of the photoluminescence with a much elevated intensity, as a unique case of aggregation-induced emission in an extended solid system, further confirmed by DFT analysis on bonding.

Tunable 4f/5f Bimodal Emission in Europium-Incorporated Uranyl Coordination Polymers.

There have been numerous studies on emission-color regulation by the adjustment of molar amounts of multiple trivalent lanthanide cations, such as Eu, Tb, Dy, and others, in many types of solid host materials. Although uranyl emission originating from charge-transfer transitions has been well-recognized and investigated for many decades, as of now there is no report on tunable 4f/5f bimodal emission based on heterobimetallic lanthanide(III) and uranyl(VI) compounds. In most cases, complete energy transfer between uranyl(VI) and lanthanide(III) centers was observed.

A hydrolytically stable uranyl organic framework for highly sensitive and selective detection of Fe in aqueous media.

We present a depleted uranium-based metal organic framework, UO(CHON)·DMF, that exhibits highly sensitive and selective detection towards Fe ions in aqueous media with an extremely low detection limit of 6.3 ppb. This work offers insight into exploring the potential applications of actinide-based metal organic frameworks in the area of chemical sensing with intrinsic advantages of high selectivity and sensitivity.

Metal-organic frameworks for radionuclide sequestration from aqueous solution: a brief overview and outlook.

In this Frontier article, we pursue the sequestration of radionuclides from aqueous solution by using recently emerging metal-organic framework (MOF) materials. The design of MOF materials and their corresponding sorption properties towards radionuclides (Cs, Sr, U, Se, and Tc) as well as their interaction mechanisms are highlighted. The present challenges and future prospects of removing radionulides with MOFs as sorbents are also demonstrated.

Identifying the Recognition Site for Selective Trapping of TcO in a Hydrolytically Stable and Radiation Resistant Cationic Metal-Organic Framework.

Effective and selective removal of TcO from aqueous solution is highly desirable for both waste partitioning and contamination remediation purposes in the modern nuclear fuel cycle, but is of significant challenge. We report here a hydrolytically stable and radiation-resistant cationic metal-organic framework (MOF), SCU-101, exhibiting extremely fast removal kinetics, exceptional distribution coefficient, and high sorption capacity toward TcO. More importantly, this material can selectively remove TcO in the presence of large excesses of NO and SO, as even 6000 times of SO in excess does not significantly affect the sorption of TcO.

Electronic Structure and Properties of Berkelium Iodates.

The reaction of Bk(OH) with iodate under hydrothermal conditions results in the formation of Bk(IO) as the major product with trace amounts of Bk(IO) also crystallizing from the reaction mixture. The structure of Bk(IO) consists of nine-coordinate Bk cations that are bridged by iodate anions to yield layers that are isomorphous with those found for Am, Cf, and with lanthanides that possess similar ionic radii. Bk(IO) was expected to adopt the same structure as M(IO) (M = Ce, Np, Pu), but instead parallels the structural chemistry of the smaller Zr cation.

Characterization of berkelium(III) dipicolinate and borate compounds in solution and the solid state.

Berkelium is positioned at a crucial location in the actinide series between the inherently stable half-filled 5f(7) configuration of curium and the abrupt transition in chemical behavior created by the onset of a metastable divalent state that starts at californium. However, the mere 320-day half-life of berkelium's only available isotope, (249)Bk, has hindered in-depth studies of the element's coordination chemistry. Herein, we report the synthesis and detailed solid-state and solution-phase characterization of a berkelium coordination complex, Bk(III)tris(dipicolinate), as well as a chemically distinct Bk(III) borate material for comparison.

Covalency-Driven Dimerization of Plutonium(IV) in a Hydroxamate Complex.

The reaction of formohydroxamic acid [NH(OH)CHO, FHA] with Pu(III) should result in stabilization of the trivalent oxidation state. However, slow oxidation to Pu(IV) occurs, which leads to formation of the dimeric plutonium(IV) formohydroxamate complex Pu2(FHA)8. In addition to being reductants, hydroxamates are also strong π-donor ligands.