The study of facile‐synthesis and low‐cost X‐ray scintillators with high light yield, low detection limit and high X‐ray imaging resolution plays a vital role in medical and industrial imaging ...fields. However, the optimal balance between X‐ray absorption, decay lifetime and excitonic utilization efficiency of scintillators to achieve high‐resolution imaging is extremely difficult due to the inherent contradiction. Here two thermally activated delayed fluorescence (TADF)‐actived coinage‐metal clusters M6S6L6 (M=Ag or Cu) were synthesized by simple solvothermal reaction, where the cooperation of heavy atom‐rich character and TADF mechanism supports strong X‐ray absorption and rapid luminescent collection of excitons. Excitingly, Ag6S6L6 (SC‐Ag) displays a high photoluminescence quantum yield of 91.6 % and scintillating light yield of 17420 photons MeV−1, as well as a low detection limit of 208.65 nGy s−1 that is 26 times lower than the medical standard (5.5 μGy s−1). More importantly, a high X‐ray imaging resolution of 16 lp/mm based on SC‐Ag screen is demonstrated. Besides, rigid core skeleton reinforced by metallophilicity endows clusters M6S6L6 strong resistance to humidity and radiation. This work provides a new view for the design of efficient scintillators and opens the research door for silver clusters in scintillation application.
High X‐ray absorption and thermally activated delayed fluorescence (TADF) properties jointly support hexanuclear cluster scintillators for high‐resolution imaging.
Anisotropic charge transport plays a pivotal role in clarifying the conductivity mechanism in direct X-ray detection to improve the detection sensitivity. However, the anisotropic photoelectric ...effect of semiconductive single crystal responsive to X-ray is still lacking of theoretical and experimental proof. The semiconductive coordination polymers (CPs) with designable structures, adjustable functions, and high crystallinity provide a suitable platform for exploring the anisotropic conductive mechanism. Here,the study first reveals a 1D conductive transmission path for direct X-ray detection from the perspective of structural chemistry. The semiconductive copper(II)-based CP 1 single crystal detector exhibits unique anisotropic X-ray detection performance. Along the 1D π-π stacking direction, the single crystal device (1-SC-a) shows a superior sensitivity of 2697.15 µCGy
cm
and a low detection limit of 1.02 µGy
s
among CPs-based X-ray detectors. This study provides beneficial guidance and deep insight for designing high-performance CP-based X-ray detectors.
Energetic materials (EMs) have been widely employed in both military and civilian areas for nearly two centuries. The introduction of high-energy azide anions to assemble energetic metal–organic ...frameworks (EMOFs) is an efficient strategy to enhance energetic properties. However, azido-based EMOFs always suffer low stabilities to external mechanical stimulation. Herein, we employed an in situ hydrothermal reaction as a technique to refine azide anions with a neutral triazole-cyano-based ligand TrzAt (TrzAt = 2-(1 H -1,2,4-triazol-1-yl)acetonitrile) to yield two tetrazole-based EMOFs, namely, ZnBr(trmetz) n 1 and Cd(trmetz) 2 n 2 (Htrmetz = 5-(1,2,4-triazol-1-ylmethyl)-1 H -tetrazole). Compound 1 features a closely packed 2D layered network, while compound 2 exhibits a 3D architecture. With azide anions inlaid into a nitrogen-rich and chelating ligand in the EMOFs, compounds 1 and 2 present remarkable decomposition temperatures ( T dec ≥ 300 °C), low impact sensitivities (IS ≥ 32 J) and low friction sensitivities (FS ≥ 324 N). The calculated heat of detonation (Δ H det ) values of 1 and 2 are 3.496 and 4.112 kJ g −1 , respectively. In particular, the Δ H det value of 2 is higher than that of traditional secondary explosives such as 2,4,6-trinitrotoluene (TNT, Δ H det = 3.720 kJ g −1 ). These results indicate that EMOFs 1 and 2 may serve as potential replacements for traditional secondary explosives. This work provides a simple and effective strategy to obtain two EMOFs with satisfactory energy densities and reliable stabilities through an in situ hydrothermal technique for desensitization of azide anions.
Doxorubicin- (DOX-) related cardiac injury impairs the life quality of patients with cancer. This largely limited the clinical use of DOX. It is of great significance to find a novel strategy to ...reduce DOX-related cardiac injury. Oroxylin A (OA) has been identified to exert beneficial effects against inflammatory diseases and cancers. Here, we investigated whether OA could attenuate DOX-induced acute cardiotoxicity in mice. A single dose of DOX was used to induce acute cardiac injury in mice. To explore the protective effects, OA was administered to mice for ten days beginning from five days before DOX injection. The data in our study indicated that OA inhibited DOX-induced heart weight loss, reduction in cardiac function, and the elevation in myocardial injury markers. DOX injection resulted in increased oxidative damage, inflammation accumulation, and myocardial apoptosis in vivo and in vitro, and these pathological alterations were alleviated by treatment of OA. OA activated the sirtuin 1 (Sirt1) signaling pathway via the cAMP/protein kinase A, and its protective effects were blocked by Sirt1 deficiency. OA treatment did not affect the tumor-killing action of DOX in tumor-bearing mice. In conclusion, OA protected against DOX-related acute cardiac injury via the regulation of Sirt1.
Advancement in explosive systems toward miniaturization and enhanced safety has prompted the development of primary explosives with powerful detonation performance and relatively low sensitivities. ...Energetic coordination polymers (ECPs) as a new type of energetic materials have attracted wide attention. However, regulating the energetic characters of ECPs and establishing the relationship between structure and energetic property remains great challenges. In this study, two isomorphic 2D π-stacked solvent-free coordination polymers, M(N3)2(atrz) n (M = Co 1, Cd 2; atrz = 4,4′-azo-1,2,4-triazole), were hydrothermally prepared and structurally characterized by X-ray diffraction. The two compounds exhibit reliable stabilities, remarkable positive enthalpies of formation, and prominent heats of detonation. The enthalpy of formation of 1 is 4.21 kJ·g–1, which is higher than those of all hitherto known primary explosives. Repulsive steric clashes between the sensitive azide ions in 1 and 2 influence the mechanical sensitivities deduced from the calculated noncovalent interaction domains. The two energetic π-stacked ECPs 1 and 2 can serve as candidates for primary explosives with an approved level of safety.
Flexible Pb-MOF film serves as a scintillator screen for sensitive X-ray detection and high-resolution X-ray imaging.
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•The Pb-MOF composite film is firstly used as the scintillating ...screen for X-ray imaging.•Lead-based metal–organic framework scintillator is prepared via the mild method.•Synergistic effect of inorganic and organic motifs in Pb-MOF is responsible for sensitive X-ray response.
Scintillators that exhibit X-ray stimulated light response have attracted increasing attention for their wide application in medical diagnosis and treatment, security inspection, industrial flaw detection and other aspects. However, the broader application of traditional inorganic and organic scintillators has been limited by their high preparation cost or poor adaptability to changeable environments. Here, a scintillating 1D metal–organic framework (MOF) Pb(adda)(DMF)n1 (H2adda = (2E,2′E)-3,3′-(anthracene-9,10-diyl) diacrylic acid, DMF = N,N-dimethylformamide) was prepared by a low-cost and short-cycle solvothermal process. Benefiting from the intrinsic synergistic effect of functional motifs and robust architecture, sensitive and steady X-ray response signals of 1 are demonstrated with an excellent linearity to the X-ray dose rates and stable light output under 9 h per day continuous irradiation during five days. In addition, the flexible MOF-based scintillator film is firstly applied in X-ray imaging application, which achieves a relatively high spatial resolution of 5.5 lp mm−1. This work provides an effective visualization tool for X-ray radiography and verifies the potential application of flexible MOF-based scintillator film for X-ray imaging.
Luminescent metal halides have been exploited as a new class of X-ray scintillators for security checks, nondestructive inspection, and medical imaging. However, the charge traps and hydrolysis ...vulnerability are always detrimental to the three-dimensional ionic structural scintillators. Here, the two zero-dimensional organic-manganese(II) halide coordination complexes 1-Cl and 2-Br were synthesized for improvements in X-ray scintillation. The introduction of a polarized phosphine oxide can help to increase the stabilities, especially the self-absorption-free merits of these Mn-based hybrids. The X-ray dosage rate detection limits reached up to 3.90 and 0.81 μGyair/s for 1-Cl and 2-Br, respectively, superior to the medical diagnostic standard of 5.50 μGyair/s. The fabricated scintillation films were applied to radioactive imaging with high spatial resolutions of 8.0 and 10.0 lp/mm, respectively, holding promise for use in diagnostic X-ray medical imaging.
Efficient cathode-ray scintillating metal-organic frameworks are constructed from a π-conjugated luminescent motif and light Ca(
ii
) ions. The luminescence self-quenching pathway has been ...effectively hindered through coordination.
In situ
vacuum ultraviolet fluorescent spectra have shown the excitons recombining in the scintillation process for the first time.
π-Conjugated luminescent motifs that suffer from aggregation-caused quenching can respond well to ionizing cathode-rays after coordination with Ca(
ii
) ions.
A scarce insensitive azide-based energetic compound was obtained. Two structural models were first proposed for elucidation of the distinct sensitivities.
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•Four novel azide-based ECPs ...are prepared via the efficient method.•Compound 1 features scarce insensitivity among azide-based ECPs.•Two new structural models have been first proposed for elucidating different sensitivities.
Energetic coordination polymers (ECPs), as a new class of energetic materials (EMs), have attracted extensive attention in recent years. However, controllable modulation of mechanical sensitivities and the establishment of structure-function theoretical models of ECPs to meet different applications remain great challenges. Herein, we designed and synthesized four azide-based ECPs, Cd2(N3)2(datz)2n1 (Hdatz = 3,5-diamino-1,2,4-triazole), Cd(N3)2(brt)2n2 (brt = 4,4′-bi-1,2,4-triazole), Cd(N3)2(btzp)n3 (btzp = 1,3-di(tetrazol-1-yl)propane), and Cd2(N3)4(btzb)n4 (btzb = 1,4-bis(tetrazol-1-yl)butane). Because of the existence of consolidated network structures, high-energy linkers, and diverse structural motifs, compounds 1–4 exhibit reliable thermal stabilities, tunable mechanical sensitivities, and considerable heats of detonation (ΔHdet) with the ΔHdet values of 3.390, 3.412, 3.947 and 4.504 kJ·g−1, respectively, which are two times higher than those of commercial LA (lead azide) and the reported AgMtta (AgMtta = Ag(Mtta)n, HMtta = 5-methyl-1H-tetrazole). The sensitivity measurements demonstrate that the sensitivity toward impact of 1–4 displays in the following order: 1 (>40 J) ≪ 2 (8 J) < 3 (2.5 J) < 4 (2 J). In particular, compound 1 features scarce insensitivity compared with sensitive 2, 3, 4 and most of known azide-based EMs. Furthermore, theoretical calculations, structural analyses, and experimental results revealed that the different sensitivities of the four ECPs are mainly dependent on two different structure models for the first time. The insensitive 1 is “body frame structure” model, while the sensitive 2–4 belong to “non-body frame structure” model. Our study enlightens new insights into structures behind mechanical sensitivities for optimizing advanced EMs.
Luminescent multidentate naphthalene-sulfonic moieties and non-toxic barium ions worked synergistically to fabricate scintillating barium-based metal–organic frameworks into latent applications of ...X-ray dosage detection with their merited intrinsic energy resolution.
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