Acetylene (C2H2) capture is a step in a number of industrial processes, but it comes with a high‐energy footprint. Although physisorbents have the potential to reduce this energy footprint, they are ...handicapped by generally poor selectivity versus other relevant gases, such as CO2 and C2H4. In the case of CO2, the respective physicochemical properties are so similar that traditional physisorbents, such as zeolites, silica, and activated carbons cannot differentiate well between CO2 and C2H2. Herein, we report that a family of three isostructural, ultramicroporous (<7 Å) diamondoid metal–organic frameworks, Cu(TMBP)X (TMBP=3,3′,5,5′‐tetramethyl‐4,4′‐bipyrazole), TCuX (X=Cl, Br, I), offer new benchmark C2H2/CO2 separation selectivity at ambient temperature and pressure. We attribute this performance to a new type of strong binding site for C2H2. Specifically, halogen⋅⋅⋅HC interactions coupled with other noncovalent in a tight binding site is C2H2 specific versus CO2. The binding site is distinct from those found in previous benchmark sorbents, which are based on open metal sites or electrostatic interactions enabled by inorganic fluoro or oxo anions.
A new benchmark for C2H2 separation over CO2 was set by a crystal engineered family of ultramicroporous halogen‐functionalised MOFs, thanks to acetylene binding sites involving C−H⋅⋅⋅halogen interactions. Trace C2H2 capture was realized in these hydrolytically stable sorbents, only the second occurrence among metal–organic physisorbents (see figure).
Copper (II) is one of the most of important cofactors for numerous enzymes and has captured broad attention due to its role as a neurotransmitters for physiological and pathological functions. In ...this article, we present a reaction-based fluorescent sensor for Cu2+ detection (NIR-Cu) with near-infrared excitation and emission, including probe design, structure characterization, optical property test and biological imaging application. NIR-Cu is equipped with a functional group, 2-picolinic ester, which hydrolyzes in the presence of Cu2+ with high selectivity over completed cations. With the experimental conditions optimized, NIR-Cu (5μM) exhibits linear response for Cu2+ range from 0.1 to 5μM, with a detection limit of 29nM. NIR-Cu also shows excellent water solubility and are highly responsive, both desirable properties for Cu2+ detection in water samples. In addition, due to its near-infrared excitation and emission properties, NIR-Cu demonstrates outstanding fluorescent imaging in living cells and tissues.
•A reaction-based sensor for Cu2+ detection with NIR excitation and emission.•The detection limit for Cu2+ is as low as 29nM in aqueous buffer.•The probe shows special selectivity for Cu2+ over other metal ions.
Abstract
Organic radicals feature unpaired electrons, and these compounds may have applications in biomedical technology and as materials for solar energy conversion. However, unpaired electrons tend ...to pair up (to form chemical bonds), making radicals unstable and hampering their applications. Here we report an organic radical system that is stable even at 350 °C, surpassing the upper temperature limit (200 °C) observed for other organic radicals. The system reported herein features a sulfur-rich organic linker that facilitates the formation of the radical centers; on the solid-state level, the molecules are crystallized with Eu(III) ions to form a 3D framework featuring stacks of linker molecules. The stacking is, however, somewhat loose and allows the molecules to wiggle and transform into sulfur-stabilized radicals at higher temperatures. In addition, the resulting solid framework remains crystalline, and it is stable to water and air. Moreover, it is black and features strong broad absorption in the visible and near IR region, thereby enhancing both photothermal conversion and solar-driven water evaporation.
OBJECTIVE： To study the possible roles of Jinlong capsule （JLC） on the proliferation and apoptosis of human pancreatic cancer cells BxPC-3. METHODS： The human pancreatic cancer cells Bx- PC-3 were ...treated with JLC at the concentration of 0.05-1.00 mg/mL for 24-120 h. The inhibition rate of JLC on human pancreatic cancer cells BxPC-3 was detected by 3-（4,5-dimethiylthiazol-2-yl）-2, 5-diphe- nyl tetrazolium bromide （MTT） assay. Flow cytome- try was employed to measure cell apoptosis using Annexin V-FITC/Propidium iodide （AV-FITC/PI） method. Cell cycles were determined by PI staining. The expression of S100 Calcium binding protein A4 （S100A4） in cell matrix was measured by en- zyme-linked immunosorbent assay （ELISA）. The ex- pression levels of apoptosis-related protein such as BCL2/adenovirus E1B 19 kDa interacting protein 3 （BNIP3）, B-cell lymphoma/leukemia-2 （Bcl-2） andCys-teinylaspartate specific proteinase 3 （Cas- pase-3） were detected by Western blotting. RESULTS： JLC significantly inhibited the prolifera- tion of human pancreatic cancer cells BxPC-3 in a dose-dependent and time-dependent manner. JLC promoted cell apoptosis and maintained cell cycle in S and G2/M phase rather than G1/G0 phase. The expression of S100A4 in the cell matrix was re- duced. The expression of cell apoptotic protein BNIP3 was increased while Bcl-2 was decreased. CONCLUSION： JLC can inhibit the proliferation of human pancreatic cancer cells BxPC-3 by stimulat- ing cell apoptosis, arresting the cell cycle at S and G2/M phase which blocks the circulation of normal cell cycle and reducing the expression of S100A4 protein. Higher pro-apoptosis protein BNIP3 and lower anti-apoptosis protein Bcl-2 levels were found, which may be related to the apoptotic ef- fects of JLC.
With 2-COOH and 4-SH donors all packed onto the benzene ring, tetrasulfanyl terephthalic acid (TST) is a simple yet fully equipped ligand to move the field of metal-coordination materialsit is now ...accomplished. The hard-soft carboxyl-thiol synergy is leveraged here in selectively bonding the carboxyl units to Zr(IV) ions to form the same cubic net of UiO-66 (this being based on the terephthalic linker)with the free-standing dithiolene units equipping the grid of ZrTST. The 3D network of ZrTST averages about 7.6 connections as in Zr6O4(OH)4(C8H4O4S4)3.8, with the other 4.4 sealed by acetate ions. The ZrTST solid is stable in boiling water (it is formed in water/acetic acid/ethane dithiol) and remains ordered even above 300 °C. The thiol-enabled ZrTST (powder) takes up mercury from water with a high distribution coefficient K d (e.g., 1.2 × 106 mL·g–1); it also shows proton conductivity (1.9 × 10–3 S·cm–1 at 90 °C and 90% relative humidity), which, most notably, increases to a highest value of 3.7 × 10–1 S·cm–1 after oxidizing the −SH into the −SO3H groups.
Metal–organic framework (MOF) solids with their variable functionalities are relevant for energy conversion technologies. However, the development of electroactive and stable MOFs for ...electrocatalysis still faces challenges. Here, a molecularly engineered MOF system featuring a 2D coordination network based on mercaptan–metal links (e.g., nickel, as for Ni(DMBD)‐MOF) is designed. The crystal structure is solved from microcrystals by a continuous‐rotation electron diffraction (cRED) technique. Computational results indicate a metallic electronic structure of Ni(DMBD)‐MOF due to the Ni–S coordination, highlighting the effective design of the thiol ligand for enhancing electroconductivity. Additionally, both experimental and theoretical studies indicate that (DMBD)‐MOF offers advantages in the electrocatalytic oxygen evolution reaction (OER) over non‐thiol (e.g., 1,4‐benzene dicarboxylic acid) analog (BDC)‐MOF, because it poses fewer energy barriers during the rate‐limiting *O intermediate formation step. Iron‐substituted NiFe(DMBD)‐MOF achieves a current density of 100 mA cm−2 at a small overpotential of 280 mV, indicating a new MOF platform for efficient OER catalysis.
Molecular design and crystal engineering strategy are applied to construct thiol‐functionalized metal–organic frameworks (MOFs). This MOF platform is successfully decorated with nickel–sulfur links cooperating in the network. The prepared 2D MOF with enhanced electro‐conductivity and modified electronic structure demonstrates superior activity and robust stability toward the oxygen evolution reaction (OER), which paves the way to design MOFs at a molecular level.
Alkaline phosphatase (ALP) is a family of enzymes involved in the regulation of important biological processes such as cell differentiation and bone mineralization. Monitoring the activity of ALP in ...serum can help diagnose a variety of diseases including bone and liver diseases. There has been growing interest in developing new chemical tools for monitoring ALP activity in living systems. Such tools will help further delineate the roles of ALP in biological and pathological processes. Previously reported fluorescent probes has a number of disadvantages that limit their application, such as poor selectivity and short-wavelength excitation. In this work, we report a new two-photon fluorescent probe (TP-Phos) to selectively detect ALP activity. The probe is composed of a two-photon fluorophore, a phosphate recognition moiety, and a self-cleavable adaptor. It offers a number of advantages over previously reported probes, such as fast reaction kinetics, high sensitivity and low cytotoxicity. Experimental results also showed that TP-Phos displayed improved selectivity over DIFMUP, a commonly utilized ALP probe. The selectivity is attributed to the utilization of an ortho-functionalised phenyl phosphate group, which increases the steric hindrance of the probe and the active site of phosphatases. Moreover, the two-photon nature of the probe confers enhanced imaging properties such as increased penetration depth and lower tissue autofluorescence. TP-Phos was successfully used to image the endogenous ALP activity of hippocampus, kidney and liver tissues from rat.
Two chiral coordination polymers CuI(TMBP)(CH3CN)2·ClO4n (1) and ZnII(TMBP)(SCN)2n (2) have been synthesized with 3,3’,5,5’-tetramethyl-4,4’-bipyrazole (TMBP) as ligand. Their structures were ...determined by single-crystal X-ray diffraction (SCXRD) analysis and further characterized by power X-ray diffraction (PXRD) analysis, FT-IR spectroscopy, and thermogravimetric (TG) analysis. 1 is constructed by left-handed double-stranded helices with the same chirality, while 2 possesses right-handed single-helical chains. The existence of ClO4− in 1 might be the main reason for forming double-stranded helices, while it leads to single-helical chains under induction of SCN−, exhibiting a anion-directed synthesis process. The selected two single crystals are both homochiral according to the Flack parameters (≈0) from crystal refinement. The bulk sample of 1 exhibits a negative solid-state Cotton effect, while that of 2 shows a positive one. In addition, the crystal sample of 1 exhibits strong ligand-based and metal to ligand charge transition (MLCT) emission in solid-state luminescence with comparison to weakly luminous 2 at room temperature.
Two kinds of homochiral crystals of coordination polymers were achieved from anions-induced solvothermal method, and their spectral properties were investigated and compared. Display omitted
•Two kinds of homochiral crystals were prepared and determined by SCXRD.•ClO4−-directed 1 possesses double-stranded helices while SCN−-induced 2 possesses single-helical chains.•Bulk sample of 1 exhibits MLCT emission with comparison to weakly luminous 2.
A new avenue for making porous frameworks has been developed by borrowing an idea from molecularly imprinted polymers (MIPs). In lieu of the small molecules commonly used as templates in MIPs, soft ...metal components, such as CuI, are used to orient the molecular linker and to leverage the formation of the network. Specifically, a linear dicarboxylate linker with thioether side groups reacted simultaneously with Ln3+ ions and CuI, leading to a bimetallic net featuring strong, chemically hard Eu3+–carboxylate links, as well as soft, thioether‐bound Cu2I2 clusters. The CuI block imparts water stability to the host; with the tunable luminescence from the lanthanide ions, this creates the first white‐emitting MOF that is stable in boiling water. The Cu2I2 block also readily reacts with H2S, and enables sensitive colorimetric detection while the host net remains intact.
White light/white heat: A porous metal–organic framework, inspired by conceptually crosscutting the molecular imprint of polymers and the template of zeolites, emits white light in boiling water. The MOF incorporates an effective hard‐and‐soft divide, in which the EuIII–carboxylate framework holds up the primary grid, whereas the imbedded soft CuI block, like a template, can be dislodged (e.g., by reacting with H2S) from the surrounding sulfur donors while the host net remains intact.
We report a curious porous molecular crystal that is devoid of the common traits of related systems. Namely, the molecule does not rely on directional hydrogen bonds to enforce open packing, and it ...offers neither large concave faces (i.e., high internal free volume) to frustrate close packing, nor any inherently built-in cavity like in the case of organic cages. Instead, the permanent porosity (as unveiled by the X-ray crystal structure and CO2 sorption studies) arises from the strong push–pull units built into a Sierpinski-like molecule that features four symmetrically backfolded side arms. Each side arm consists of the 1,1,4,4-tetracyanobuta-1,3-diene acceptor coupled with the dimethylaminophenyl donor, which is conveniently installed by a cycloaddition–retroelectrocyclization reaction. Unlike the poor/fragile crystalline order of many porous molecular solids, the molecule here readily crystallizes, and the crystalline phase can be easily deposited into thin films from solutions. Moreover, both the bulk sample and thin film exhibit excellent thermal stability with the porous crystalline order maintained even at 200 °C. The intermolecular forces underlying this robust porous molecular crystal likely include the strong dipole interactions and the multiple C···N and C···O short contacts afforded by the strongly donating and accepting groups integrated within the rigid molecular scaffold.
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