The potential applications of metal–organic cages (MOCs) are mostly achieved through specific host–guest interactions within their cavities. Electronic applications would require an effective ...electron transport pathway, which has been extensively studied in hybrid organic–inorganic materials with extended structures. These properties have not been considered for MOCs because cage-to-cage interactions in these materials have rarely been examined and are challenging to functionalize. We report here a previously unobserved actinide-based MOC assembled from four hexagonal-bipyramidal-coordinated uranyl ions and six bidentate flexible ligands. Remarkably, each isolated cage is further interlocked with six adjacent ones through mechanical bonds, resulting in the first case of a 0D → 3D f-element polycatenated metal–organic cage, SCU-14. Long-range π–π stacking extending throughout the structure is built via polycatenation, providing a visible carrier transmission path. SCU-14 is also an extremely rare case of an intrinsically semiconductive MOC with a wide band gap of 2.61 eV. Combined with the high X-ray attenuation efficiency, SCU-14 can effectively convert X-ray photons to electrical current signals and presents a promising sensitivity of 54.93 μC Gy–1 cm–2.
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 10−4 Gy, representing a significant improvement on the detection limit of approximately two orders of magnitude, compared to other chemical dosimeters reported up to now. The electron paramagnetic resonance analysis suggests that with the exposure to radiations, the carbonyl double bonds break affording oxo‐radicals that can be stabilized within the conjugated uranium oxalate‐carboxylate sheet. This gives rise to a substantially enhanced equatorial bonding of the uranyl(VI) ions as elucidated by the single‐crystal structure of the γ‐ray irradiated material, and subsequently leads to a very effective photoluminescence quenching through phonon‐assisted relaxation. The quenched sample can be easily recovered by heating, enabling recycled detection for multiple runs.
A uranium MOF dosimeter: A photoluminescent uranium–organic framework, whose intensity accurately correlates with the exposure dose of X‐ or γ‐radiations, enables the precise and instant detection of ionizing radiations. The detection limit of 10−4 Gy represents an improvement of approximately two orders of magnitude compared to other chemical dosimeters reported up to now.
Semiconductive metal–organic frameworks (MOFs) have attracted extraordinary research interest in recent years; however, electronic applications based on these emerging materials are still in their ...infancy. Herein, we show that a lanthanide-based semiconductive MOF (SCU-12) can effectively convert X-ray photons to electrical current signals under continuous hard X-ray radiation. The semiconductive MOF-based polycrystalline detection device presents a promising X-ray sensitivity with the value of 23.8 μC Gyair –1 cm–2 under 80 kVp X-ray exposure, competitive with the commercially available amorphous selenium (α-Se) detector. The lowest detectable X-ray dose rate is 0.705 μGy s–1, representing the record value among all X-ray detectors fabricated by polycrystalline materials. This work discloses the first demonstration of hard radiation detection by semiconductive MOFs, providing a horizon that can guide the synthesis of a new generation of radiation detection materials by taking the advantages of structural designability and property tunability in the MOF system.
The combination of high atomic number and high oxidation state in UVI 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 UVI 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. Combining the advantage in minimizing the non‐radiative relaxation during the X‐ray excitation process over those of inorganic salts of uranium, SCU‐9 exhibits a very efficient X‐ray to green light luminescence conversion. The luminescence intensity shows an essentially linear correlation with the received X‐ray intensity, and is comparable with that of commercially available CsI:Tl. SCU‐9 possesses an improved X‐ray attenuation efficiency (E>20 keV) as well as enhanced radiation resistance and decreased hygroscopy compared to CsI:Tl.
U are scintillating: The observation of intense X‐ray scintillation in a uranyl‐organic framework is reported. Advances are shown in X‐ray attenuation efficiency (E>20 keV) as well as enhanced radiation resistance and decreased hygroscopy when compared to the commercially available scintillator CsI:Tl.
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. Th4+ in SCU‐11 is 10‐coordinate with a bicapped square prism coordination geometry, which has never been documented for any metal cation complexes. The bicapped position is occupied by two coordinated water molecules that can be removed to afford a very unique open Th4+ site, confirmed by X‐ray diffraction, color change, thermogravimetry, and spectroscopy. The degassed phase (SCU‐11‐A) exhibits a Brunauer–Emmett–Teller surface area of 1272 m2 g−1, one of the highest values among reported actinide materials, enabling it to sufficiently retain water vapor, Kr, and Xe with uptake capacities of 234 cm3 g−1, 0.77 mmol g−1, 3.17 mmol g−1, respectively, and a Xe/Kr selectivity of 5.7.
A 3D porous thorium framework has a new coordination geometry for a 10‐coordinate metal ion: bicapped tetragonal prism. The framework (SCU‐11) is also one of the most porous actinide materials reported and features a unique open Th4+ site after activation, leading to superior water vapor and Xe/Kr uptake and separation.
Radiation dosimeters displaying conspicuous response of irradiance are highly desirable, owing to the growing demand of monitoring high-energy radiation and environmental exposure. Herein, we present ...a case of dosimetry based on a discrete nanocluster, Th
(OH)
(O)
(H
O)
(TPC)
(HCOO)
∙4DMF∙H
O (Th-SINAP-100), by judiciously incorporating heavy Th
polynuclear centers as radiation attenuator and organic linkers as photo-responsive sensor. Interestingly, dual-module photochromic transitions upon multiple external stimuli including UV, β-ray, and γ-ray are integrated into this single material. The striking color change, and more significantly, the visible color transition of luminescence in response to accumulating radiation dose allow an on-site quantitative platform for naked-eye detection of ionization radiations over a broad range (1-80 kGy). Single crystal X-ray diffraction and density functional theory calculations reveal that the dual-module photochromism can be attributed to the π(TPC) → π*(TPC) intermolecular charge transfer driven by enhanced π-π stacking interaction between the adjacent TPC moieties upon irradiation.
Lanthanides possess similar chemical properties rendering their separation from one another a challenge of fundamental chemical and global importance given their incorporation into many advanced ...technologies. New separation strategies combining green chemistry with low cost and high efficiency remain highly desirable. We demonstrate that the subtle bonding differences among trivalent lanthanides can be amplified during the crystallization of borates, providing chemical recognition of specific lanthanides that originates from Ln
coordination alterations, borate polymerization diversity and soft ligand coordination selectivity. Six distinct phases are obtained under identical reaction conditions across lanthanide series, further leading to an efficient and cost-effective separation strategy via selective crystallization. As proof of concept, Nd/Sm and Nd/Dy are used as binary models to demonstrate solid/aqueous and solid/solid separation processes. Controlling the reaction kinetics gives rise to enhanced separation efficiency of Nd/Sm system and a one-step quantitative separation of Nd/Dy with the aid of selective density-based flotation.
Hyperoside (quercetin 3-
-β-d-galactopyranoside) is one of the flavonoid glycosides with anti-inflammatory, antidepressant, and anti-cancer effects. But it remains unknown whether it had effects on ...breast cancer. Here, different concentrations of hyperoside were used to explore its therapeutic potential in both breast cancer cells and subcutaneous homotransplant mouse model. CCK-8 and wound healing assays showed that the viability and migration capability of Michigan Cancer Foundation-7 (MCF-7) and 4T1 cells were inhibited by hyperoside, while the apoptosis of cells were increased. Real-time quantitative PCR (qRT-PCR) and western blot analysis were used to detect mRNA and the protein level, respectively, which showed decreased levels of B cell lymphoma-2 (Bcl-2) and X-linked inhibitor of apoptosis (XIAP), and increased levels of Bax and cleaved caspase-3. After exploration of the potential mechanism, we found that reactive oxygen species (ROS) production was reduced by the administration of hyperoside, which subsequently inhibited the activation of NF-κB signaling pathway. Tumor volume was significantly decreased in subcutaneous homotransplant mouse model in hyperoside-treated group, which was consistent with our study in vitro. These results indicated that hyperoside acted as an anticancer drug through ROS-related apoptosis and its mechanism included activation of the Bax-caspase-3 axis and the inhibition of the NF-κB signaling pathway.
Radio‐photoluminescence (RPL) materials display a distinct radiation‐induced permanent luminescence center, and therefore find application in the detection of ionizing radiation. The current ...inventory of RPL materials, which were discovered by serendipity, has been limited to a small number of metal‐ion‐doped inorganic materials. Here we document the RPL of a metal–organic framework (MOF) for the first time: X‐ray induced free radicals are accumulated on the organic linker and are subsequently stabilized in the conjugated fragment in the structure, while the metal center acts as the X‐ray attenuator. These radicals afford new emission features in both UV‐excited and X‐ray excited luminescence spectra, making it possible to establish linear relationships between the radiation dose and the normalized intensity of the new emission feature. The MOF‐based RPL materials exhibit advantages in terms of the dose detection range, reusability, emission stability, and energy threshold. Based on a comprehensive electronic structure and energy diagram study, the rational design and a substantial expansion of candidate RPL materials can be anticipated.
Radio‐photoluminescence in MOFs: The first metal–organic framework (MOF) to display radio‐photoluminescence (RPL) may lead to a new generation of RPL dosimeters showing advantages in terms of detection sensitivity, detection range, reusability, stability, and energy threshold over the existing commercial materials.
To evaluate whether marked myopia, compared with moderate myopia and low myopia, is associated with a higher prevalence of glaucomatous optic nerve damage.
Population-based cross-sectional study.
...Four thousand four hundred thirty-nine of 5324 subjects 40 years or older were invited to participate (response rate, 83.4%). The group was stratified according to refractive error into high myopia (myopia > -8 diopters D), marked myopia (<-6 to -8 D), moderate myopia (<-3 to -6 D), low myopia (<-0.5 to -3 D), emmetropia (-0.5 to + <2 D), and hyperopia (>+ 2 D) subgroups.
Morphologic assessment of optic disc monoscopic photographs.
Morphologic optic disc parameters and intraocular pressure (IOP).
For 4319 (97.3%) subjects (8484 eyes), optic disc photographs were evaluated. Prevalence of glaucomatous optic nerve atrophy as defined by the glaucomatous optic nerve head appearance did not vary significantly (P = 0.77; odds ratio OR, 1.2; 95% confidence interval CI, 0.38-3.81) between the highly myopic group and the group with marked myopia. In both refractive groups combined, glaucoma frequency seemed to be higher (P = 0.075; OR, 2.28; 95% CI, 0.99-5.25) higher than in the group with moderate myopia; it was significantly (P = 0.001; OR, 3.5; 95% CI, 1.71-7.25) higher than in the group with low myopia; significantly (P<0.001; OR, 7.56; 95% CI, 3.98-14.35) higher than in the group with emmetropia; and significantly (P = 0.005; OR, 4.23; 95% CI, 1.57-11.45) higher than in the group with hyperopia. Glaucoma frequency did not vary significantly between the hyperopic group and the emmetropic group (P = 0.17), the group with low myopia (P = 0.83), and the group with moderate myopia (P = 0.32). Intraocular pressure did not vary significantly (P>0.10) between any of the subgroups. Similar results were obtained for the frequency of glaucoma defined as glaucomatous optic disc appearance and visual field defects. In binary logistic regression analysis, presence of glaucoma was significantly associated with the myopic refractive error (P<0.001), age (P<0.001), and IOP (P<0.001).
Marked to high myopia with a myopic refractive error exceeding -6 D may be a risk factor associated with glaucomatous optic neuropathy.
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