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The use of molten boric acid as a reactive flux for synthesizing actinide borates has been developed in the past two years providing access to a remarkable array of exotic materials with both unusual structures and unprecedented properties. [ThB5O6(OH)6][BO(OH)2]·2.5H2O possesses a cationic supertetrahedral structure and displays remarkable anion exchange properties with high selectivity for TcO4−. Uranyl borates form noncentrosymmetric structures with extraordinarily rich topological relationships. Neptunium borates are often mixed-valent and yield rare examples of compounds with one metal in three different oxidation states. Plutonium borates display new coordination chemistry for trivalent actinides. Finally, americium borates show a dramatic departure from plutonium borates, and there are scant examples of families of actinides compounds that extend past plutonium to examine the bonding of later actinides. There are several grand challenges that this work addresses. The foremost of these challenges is the development of structure-property relationships in transuranium materials. A deep understanding of the materials chemistry of actinides will likely lead to the development of advanced waste forms for radionuclides present in nuclear waste that prevent their transport in the environment. This work may have also uncovered the solubility-limiting phases of actinides in some repositories, and allows for measurements on the stability of these materials. [ABSTRACT FROM AUTHOR]

The reaction of Np(v) chloride with molten boric acid results in the disproportionation of Np(v) into Np(iv) and Np(vi), and the crystallization of K2[(NpO2)3B10O16(OH)2(NO3)2]. UV-vis-NIR spectroscopy demonstrates that in addition to the Np(vi) and Np(v) found in the crystal structure, Np(iv) is also present. [ABSTRACT FROM AUTHOR]

Herein we report the first example of an actinide polyiodate compound, namely K4[(UO2)2(IO3)6(I4O11)]·(HIO3)4(H2O)6 (UPI-1), which was obtained from slow evaporation of nitric acid with a high I/U ratio. Spectroscopic measurements indicate that UPI-1 possesses X-ray luminescence properties applicable for X-ray scintillation and also exhibits modest protonic conduction. [ABSTRACT FROM AUTHOR]

Modulated synthesis and isoreticular expansion of Th-MOFs enable the stepwise construction of hierarchical complexes in which porosity and functionality can be fine-tuned, affording new Th-MOFs with a record high void space (74.0%), the largest surface area (3396.5 m2 g−1) among thorium materials, and excellent adsorption capacities toward radioactive iodine. [ABSTRACT FROM AUTHOR]

For the first time, we report intense X-ray scintillation enabled by a series of isotypic lanthanide (Eu and Tb) based metal–organic frameworks, initially showing a very efficient X-ray to visible light luminescence conversion. By systematic adjusting of the molar ratio of Eu3+ and Tb3+ in the same MOF structure as a traditional strategy for color-tuning in lanthanide-based photoluminescent materials, linear multicolor visualization of X-ray radiation from red to green can be facilely achieved, providing a new class of scintillating materials with continuous color tunability that can be customized for desired purposes. Moreover, these lanthanide–organic framework based scintillators exhibit excellent radiation resistance and humidity stability, in comparison with the state of the art and commercially-available X-ray scintillator, CsI:Tl. [ABSTRACT FROM AUTHOR]

When exposed to UV (365 nm, 2 mW) radiation, the bulk crystals of a two-dimensional metal–organic framework [Hphen]2[(UO2)2(ox)3] (1,phen = 1,10-phenanthroline, ox = oxalate) are exfoliated into thin sheets (2 μm) and its photoluminescence can be quenched in an incredibly sensitive manner, setting 1 as a superior UV-detection material. When upgrading the UV source into a 300 W xenon light source, the crystals of 1 can be further exfoliated into monolayer nanosheets (0.92 nm). [ABSTRACT FROM AUTHOR]

Deep eutectic mixtures were deployed for the preparation of porous layered [Sn3Se7]n2n− single crystals. The perforation on the layers accentuates the negative temperature dependence of its band gap, resulting in remarkable thermochromic performance. Substitution of the hydroxo group by the methyl group provides an enhanced hydrophobicity for the organic template, leading to an anhydrous product with a remarkably improved thermal stability and thus reversible thermochromic properties. [ABSTRACT FROM AUTHOR]

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)]·0.375DMF·0.4H2O (1); both values approach the records among all reported proton-conducting MOF materials. This suggests that the proton conduction process in 1 is reminiscent of the Grotthuss mechanism, which together reveals an effective proton transportation pathway associated with aligned Na+ and their coordinated water. [ABSTRACT FROM AUTHOR]

When exposed to water, the two-dimensional uranyl–organic layered compound [(CH3)2NH2][(UO2)(BCPBA)]·2DMF·H2O (H3BCPBA = 3,5-bis (4′-carboxylphenoxy) benzoic acid) gradually undergoes a complete single-crystal-to-single-crystal phase transition to [(CH3)2NH2][(UO2)(BCPBA)]·3.4H2O, 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. [ABSTRACT FROM AUTHOR]