Uncovering the impact of 'capsule' shaped amine-type ligands on Am(iii)/Eu(iii) separation.

Separation of trivalent actinides (An(iii)) and lanthanides (Ln(iii)) in spent nuclear fuel reprocessing is extremely challenging mainly owing to their similar chemical properties. Two amine-type reagents, tetrakis(2-pyridyl-methyl)-1,2-ethylenediamine (TPEN) and its hydrophobic derivative N,N,N',N'-tetrakis((4-butoxypyridin-2-yl)methyl)-ethylenediamine (TBPEN), have been identified to possess a selectivity for Am(iii) over Eu(iii). In this work, the structures, bonding nature, and thermodynamic behaviors of the Am(iii) and Eu(iii) complexes with these two ligands have been systematically studied via scalar relativistic density functional theory (DFT) calculations.

A mesoporous cationic thorium-organic framework that rapidly traps anionic persistent organic pollutants.

Many environmental pollutants inherently exist in their anionic forms and are therefore highly mobile in natural water systems. Cationic framework materials that can capture those pollutants are highly desirable but scarcely reported. Here we present a mesoporous cationic thorium-based MOF (SCU-8) containing channels with a large inner diameter of 2.

Novel Viologen Derivative Based Uranyl Coordination Polymers Featuring Photochromic Behaviors.

A series of novel uranyl coordination polymers have been synthesized by hydrothermal reactions. Both complexes 1 and 2 prosess two ipbp ligands (H ipbpCl=1-(3,5-dicarboxyphenyl)-4,4'-bipyridinium chloride), one uranyl cation, and two coordination water molecules, which can further extend to 2D networks through hydrogen bonding. In complex 1, two sets of equivalent nets are entangled together, resulting in a 2D + 2D → 3D polycatenated framework.

Rational control of the interlayer space inside two-dimensional titanium carbides for highly efficient uranium removal and imprisonment.

Though two-dimensional early transition metal carbides and carbonitrides (MXenes) have attracted extensive interest recently, their superb abilities in various scientific applications always suffer from the very narrow interlayer space inside the multilayered structure. Here we demonstrate an unprecedented large adsorption capacity enhancement of TiCT toward radionuclide removal via a hydrated intercalation strategy. By rational control of the interlayer space, the potential for imprisoning the representative actinide U(vi) inside multilayered TiCT was also confirmed.

Two mTOR inhibitors, rapamycin and Torin 1, differentially regulate iron-induced generation of mitochondrial ROS.

It is generally believed that gene-environment interaction may contribute to neurodegeneration. Of particular note is that iron overload may be one of the risk factors for neurodegeneration. However, the mechanisms underlying iron-associated neurotoxicity are not fully understood.

Mild Periodic Acid Flux and Hydrothermal Methods for the Synthesis of Crystalline f-Element-Bearing Iodate Compounds.

f-element-bearing iodate compounds are a large family mostly synthesized by hydrothermal reactions starting with actinide/lanthanide ions and iodic acid or iodate salt. In this work, we introduce melting periodic acid flux as a new reaction medium and provide a safe way for single-crystal growth of a series of new f-element iodate compounds including UO(IO)·HO (1), UO(IO)(HO)·HIO (2), α-Th(IO)(NO)(OH) (3), β-Th(IO)(NO)(OH) (4), and (HO)Nd(IO)·3HIO (5). The structures of these compounds deviate from those afforded from hydrothermal reactions.

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.

Theoretically unraveling the separation of Am(iii)/Eu(iii): insights from mixed N,O-donor ligands with variations of central heterocyclic moieties.

With the fast development of nuclear energy, the issue related to spent nuclear fuel reprocessing has been regarded as an imperative task, especially for the separation of minor actinides. In fact, it still remains a worldwide challenge to separate trivalent An(iii) from Ln(iii) because of their similar chemical properties. Therefore, understanding the origin of extractant selectivity for the separation of An(iii)/Ln(iii) by using theoretical methods is quite necessary.

Ultrafast and Efficient Extraction of Uranium from Seawater Using an Amidoxime Appended Metal-Organic Framework.

Enrichment of uranyl from seawater is crucial for the sustainable development of nuclear energy, but current uranium extraction technology suffers from multiple drawbacks of low sorption efficiency, slow uptake kinetics, or poor extraction selectivity. Herein, we prepared the first example of amidoxime appended metal-organic framework UiO-66-AO by a postsynthetic modification method for rapid and efficient extraction of uranium from seawater. UiO-66-AO can remove 94.

A combined DFT and molecular dynamics study of U(VI)/calcite interaction in aqueous solution.

Here we present a combined DFT and molecular dynamics study of uranyl (U(VI)) interaction mechanisms with the calcite (104) surface in aqueous solution. The roles of three anion ligands (CO, HCO, OH) and solvation effect in U(VI) interaction with calcite have been evaluated. According to our calculations, water adsorbed on the calcite (104) surface prefers to exist in molecular state rather than dissociative state.

Supramolecular Host-Guest Inclusion for Distinguishing Cucurbit[7]uril-Based Pseudorotaxanes from Small-Molecule Ligands in Coordination Assembly with a Uranyl Center.

Although the capability of supramolecular pseudorotaxane/rotaxane systems as ligands for coordination with actinides has been identified by the on-going emerging of uranyl-organic polyrotaxane compounds, it is, however, still unknown how supramolecular inclusion affects the coordination assembly of the simple "axle" ligand with uranyl species. Herein, a semi-rigid organic dicarboxylate compound [BzBPCEt]Br (L ) is selected as a small-molecule "axle" ligand and the corresponding cucurbit[7]uril (CB7)-based [2]pseudorotaxane ligand, [BzBPCEt]Br @CB7 (L @CB7) has been also synthesized through CB7-based inclusion in this work. A detailed comparison between uranyl complexes from the "axle" ligand L and those from pseudorotaxane L @CB7 has been conducted, demonstrating the significant role of CB7-based inclusion in distinguishing supramolecular pseudorotaxane ligands from small-molecule dicarboxylates in uranyl coordination assembly.

Sorption characteristic of uranium(VI) ion onto K-feldspar.

The effect of pH, contact time, temperature, ionic strength and initial U(VI) concentration on U(VI) sorption onto K-feldspar was investigated using batch techniques. The sorption kinetics was evaluated and the activation energy was obtained based on the rate constants at different temperature. Graphical correlations of sorption isotherm models have been evaluated and applied for U(VI) uptake by K-feldspar.

Extending the Use of Highly Porous and Functionalized MOFs to Th(IV) Capture.

Thorium separation has recently become a hot topic because of the potential application of thorium as a future nuclear fuel, while metal-organic framework (MOF) materials have received much attention in the separation field due to their unique properties. Herein, a highly porous and stable MOF, UiO-66, and its carboxyl derivatives (UiO-66-COOH and UiO-66-(COOH)) were synthesized and explored for the first time for Th(IV) capture from a weak acidic solution. Although the introduction of carboxyl groups into UiO-66 leads to an obvious decrease in the surface area and pore volume, the adsorbability toward Th(IV) is greatly enhanced.

Iron modulates the activity of monoamine oxidase B in SH-SY5Y cells.

Both monoamine oxidase B (MAO-B) and iron accumulation are associated with neurologic diseases including Parkinson's disease. However, the association of iron with MAO-B activity was poorly understood. Here we took advantage of highly sensitive and specific fluorescence probes to examine the change in MAO-B activity in human dopaminergic neuroblastoma (SH-SY5Y) cells upon iron exposure.

Selenium Sequestration in a Cationic Layered Rare Earth Hydroxide: A Combined Batch Experiments and EXAFS Investigation.

Selenium is of great concern owing to its acutely toxic characteristic at elevated dosage and the long-term radiotoxicity of Se. The contents of selenium in industrial wastewater, agricultural runoff, and drinking water have to be constrained to a value of 50 μg/L as the maximum concentration limit. We reported here the selenium uptake using a structurally well-defined cationic layered rare earth hydroxide, Y(OH)Cl·1.

Exploring New Assembly Modes of Uranyl Terephthalate: Templated Syntheses and Structural Regulation of a Series of Rare 2D → 3D Polycatenated Frameworks.

The reaction of uranyl nitrate with terephthalic acid (HTP) under hydrothermal conditions in the presence of an organic base, 1,3-(4,4'-bispyridyl)propane (BPP) or 4,4'-bipyridine (BPY), provided four uranyl terephthalate compounds with different entangled structures by a pH-tuning method. [UO(TP)](HBPP)·2HO (1) obtained in a relatively acidic solution (final aqueous pH, 4.28) crystallizes in the form of a noninterpenetrated honeycomb-like two-dimensional network structure.

Iron-induced generation of mitochondrial ROS depends on AMPK activity.

Deregulated iron homeostasis is generally believed to be implicated in neurodegenerative diseases, including Parkinson's disease. Nevertheless, it is not fully understood how iron overload can elicit neuronal cell damage. Here we examined mitochondrial reactive oxygen species (ROS) levels in human dopaminergic neuroblastoma SH-SY5Y cells upon iron exposure.

Overcoming the crystallization and designability issues in the ultrastable zirconium phosphonate framework system.

Metal-organic frameworks (MOFs) based on zirconium phosphonates exhibit superior chemical stability suitable for applications under harsh conditions. These compounds mostly exist as poorly crystallized precipitates, and precise structural information has therefore remained elusive. Furthermore, a zero-dimensional zirconium phosphonate cluster acting as secondary building unit has been lacking, leading to poor designability in this system.

Systematic Investigation of the in Situ Reduction Process from U(VI) to U(IV) in a Phosphonate System under Mild Solvothermal Conditions.

The oxidation state greatly affects the chemical behavior of uranium in the nuclear fuel cycle and in the environment. Phosphonate ligands, on the other hand, show strong complexation toward uranium at different oxidation states and are widely used in nuclear fuel reprocessing. Therefore, in this work, the reduction behavior of U(VI) with the presence of a phosphonate ligand is investigated under mild solvothermal conditions.

Temperature-induced reversible single-crystal-to-single-crystal isomerisation of uranyl polyrotaxanes: an exquisite case of coordination variability of the uranyl center.

The first reversible solid-state single-crystal-to-single-crystal isomerisation mediated by the change of uranyl-ligand coordination modes, that is from seven-coordinated uranium(vi) of α-UP to six-coordinated uranium(vi) of the supramolecular isomer, β-UP, has been achieved in the uranyl polyrotaxane system by a temperature-induced strategy.

Highly Sensitive Detection of Ionizing Radiations by a Photoluminescent Uranyl Organic Framework.

Precise detection of low-dose X- and γ-radiations remains a challenge and is particularly important for studying biological effects under low-dose ionizing radiation, safety control in medical radiation treatment, survey of environmental radiation background, and monitoring cosmic radiations. We report here a photoluminescent uranium organic framework, whose photoluminescence intensity can be accurately correlated with the exposure dose of X- or γ-radiations. This allows for precise and instant detection of ionizing radiations down to the level of 10  Gy, representing a significant improvement on the detection limit of approximately two orders of magnitude, compared to other chemical dosimeters reported up to now.

Polarizable and Non-Polarizable Force Field Representations of Ferric Cation and Validations.

The AMOEBA polarizable force field of ferric ion was optimized and applied to study the hydration of ferric ion and its complexation with porphine in the aqueous phase. The nonpolarizable force field was also optimized for comparison. The AMOEBA force field was found to give a more accurate hydration free energy than the nonpolarizable force field with respect to experimental data, and correctly predict the most stable electronic state of hydrated Fe, which is the sextet state, and of the Fe-Por complex, which is the quartet state, consistent with the literature that was carried out using the DFT method.

Supramolecular Isomers of Coordination-Directed Side-Chain Polypseudorotaxanes Based on Trimeric Uranyl Oxalate Nodes.

Although the prosperity of rotaxane coordination polymers with rotaxane molecules serving as main-chain linkers is known, side-chain metal-organic polypseudorotaxanes incorporating macrocyclic host molecules have not been reported to date. Herein a new type of coordination-driven cucurbit[6]uril-bearing side-chain polypseudorotaxane, with two-dimensional trimeric uranyl-oxalate as main chains, has been synthesized. This was carried out through hydrothermal reactions of uranyl components with an in situ-formed carboxylated pseudorotaxane ligand in the presence of oxalate co-ligands.