Halogen-C2 H2 Binding in Ultramicroporous Metal-Organic Frameworks (MOFs) for Benchmark C2 H2 /CO2 Separation Selectivity.

Acetylene (C2 H2 ) 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 C2 H4 . 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 C2 H2 . 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 C2 H2 /CO2 separation selectivity at ambient temperature and pressure. We attribute this performance to a new type of strong binding site for C2 H2 . Specifically, halogen⋅⋅⋅HC interactions coupled with other noncovalent in a tight binding site is C2 H2 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 Bumper Crop of Boiling-Water-Stable Metal-Organic Frameworks from Controlled Linker Sulfuration.

The series of highly stable porous solids here feature systematic, regiospecific sulfur substitutions on the organic linkers for versatile functions. One major surprise lies in the controllable sequential reactions between sodium thiomethoxide (NaSMe) and octafluorobiphenyl-4,4'-dicarboxylic acid (H2bpdc-8F; this was readily made without precious metal catalysts). Namely, 3, 4, 6, and 8 methylthio-substitutions can be respectively achieved with regiospecificity (i.e., to produce the four molecules H2bpdc-3S5F, H2bpdc-4S4F, H2bpdc-6S2F, H2bpdc-8MS). A second surprise lies in their persistent formation of the UiO-67-type net with Zr(IV) ions, e.g., even in the case of the fully sulfurated H2bpdc-8MS. In addition to the remarkable breadth of functional control, all the Zr(IV)-based crystalline solids here are stable in boiling water (e.g., for 24 h) and in air as solventless, activated porous solids. Moreover, the thioether groups allow for convenient H2O2 oxidation to fine-tune the hydrophilicity and luminescence properties and improve proton conductivity.

A Boiling-Water-Stable, Tunable White-Emitting Metal-Organic Framework from Soft-Imprint Synthesis.

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 Ln(3+) ions and CuI, leading to a bimetallic net featuring strong, chemically hard Eu(3+) -carboxylate links, as well as soft, thioether-bound Cu2 I2 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 Cu2 I2 block also readily reacts with H2 S, and enables sensitive colorimetric detection while the host net remains intact.

Highly Polarizable Triiodide Anions (I3(-)) as Cross-Linkers for Coordination Polymers: Closing the Semiconductive Band Gap.

From a hydrothermal reaction using CuI, KI, and 3,3'5,5'-tetramethyl-4,4'-bipyrazole (TMBP), the triiodide anion I3(-) has been integrated into the water-stable 2D coordination polymer Cu(TMBP)I3 (1). In contrast with other metal triiodide complexes, 1 features remarkably small distortions in the bond distances associated with the I3(-) units (i.e., the Cu-I and I-I bonds), which effectively link up the copper(I) centers into infinite CuI3 chains. The electronic band gaps and electrical conductivity data are also found to be consistent with the I3(-) ion acting as an effective linker across the copper(I) centers.

Effect of Jinlong capsule on proliferation and apoptosis of human pancreatic cancer cells BxPC-3.

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 BxPC-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-diphenyl tetrazolium bromide (MTT) assay. Flow cytometry 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 5100 Calcium binding protein A4 (S100A4) in cell matrix was measured by enzyme-linked immunosorbent assay (ELISA). The expression levels of apoptosis-related protein such as BCL2/adenovirus E1B 19 kDa interacting protein 3 (BNIP3), B-cell lymphoma/leukemia-2 (Bcl-2) and Cys-teinylaspartate specific proteinase 3 (Caspase-3) were detected by Western blotting. RESULTS: JLC significantly inhibited the proliferation 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 5100A4 in the cell matrix was reduced. 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 stimulating 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 effects of JLC.

Molecular Engineering of Metal-Organic Frameworks as Efficient Electrochemical Catalysts for Water Oxidation.

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.

Dense Dithiolene Units on Metal-Organic Frameworks for Mercury Removal and Superprotonic Conduction.

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 materials─it 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 Kd (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.

Organic radicals stabilization above 300 °C in Eu-based coordination polymers for solar steam generation.

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.

[Research progress on anti-tumor effect of wind medicine].

Cancer research of Chinese medicine has formed some major fields, such as supporting healthy qi, heat clearing-detoxification and eliminating stasis-activating blood, and has made certain achievements. The "theory of anti-tumor effect with wind medicine" described the anti-tumor effects of wind medicine from a new view. In this review, and the relevant research was analyzed comprehensively. The mechanism and superiority of the anti-tumor effect of wind medicine was summarized, and the research problems was also discussed.

Conjugated crosslinks boost the conductivity and stability of a single crystalline metal-organic framework.

A linker molecule with four pendant thiophene functions was crystallized with Zr(iv) ions to form a semiconductive porous coordination solid (1.1 × 10-5 S cm-1). Oxidative treatment with FeCl3 guests then coupled the thiophene units to form conjugated bridges as covalent crosslinks. The resulting hybrid of a metal-organic framework and conjugated polymer featured robust crystalline order that withstood long-term air exposure and broad pH (from 0 to 12) conditions. Moreover, the homocoupled thiophene units, conjugated through sulfide links (-S-) with the linker backbone, afforded higher electronic conductivity (e.g., >2.2 × 10-3 S cm-1), which is characteristic of conductive polymer prototypes of polythiophene and polyphenylene sulfide. The crosslinked solid also exhibited proton conductivity that could be increased broadly upon H2SO4 treatment (e.g., from 5.0 × 10-7 to 1.6 × 10-3 S cm-1).

An air-stable anionic two-dimensional semiconducting metal-thiolate network and its exfoliation into ultrathin few-layer nanosheets.

The black, small-bandgap semiconducting framework Eu-dfdmat features extensive Eu3+-sulfur bridges from the linear linker 2,5-difluoro-3,6-dimercaptoterephthalate (dfdmt). Each Eu center is chelated to four dfdmt linkers to form an anionic coordination sphere involving four carboxyl O and four mercapto S centers (EuO4S4), wherein the charge buildup can be alleviated by the electron-withdrawing fluoro groups. The extensive metal-linker bonding, together with a trace of Eu2+ species, appears to boost electronic interaction in the 2D net, generating a small band gap of 1.31 eV (946 nm), albeit a modest conductivity (e.g., 10-6 S m-1). The crystals also exhibit persistent EPR signals indicative of organic radicals (g = 2.002). The Eu-dfdmt solid are stable in air and can be exfoliated into ultrathin nanosheets (ca. 5 nm; 6-8 layers).

Janus triple tripods build up a microporous manifold for HgCl2 and I2 uptake.

To boost the design of microporous solids, we integrated a two-faced shape (as in cucurbiturils and cyclodextrins) into the building blocks of framework materials. Reported herein is a planar tritopic carboxyl linker with secondary tripod donors sprouting off both sides at the core region. The two-faced, barrel-like core region imparts a rugged 3D character to the linker architecture, obviating close packing and creating complex-shaped cavities in an Eu(iii)-carboxylate network. The merits extend beyond the interesting shape of the multiple tripod: e.g., the two sets of sulfur tripods at the barrel region, together with the triazine center, offer a rich array of donors for adsorbing Hg(ii) ions. The microporous solid also removes iodine from vapor and water, and can be easily cycled in column chromatography.

Synthesis of a Thiol Building Block for the Crystallization of a Semiconducting Gyroidal Metal-sulfur Framework.

We present a method for preparing thioester molecules as the masked form of the thiol linkers and their utilization for accessing a semiconducting and porous metal-dithiolene network in the highly ordered single crystalline state. Unlike the highly reactive free-standing thiols, which tend to decompose and complicate the crystallization of metal-thiolate open frameworks, the thioester reacts in situ to provide the thiol species, serving to mitigate the reaction between the mercaptan units and the metal centers, and to improve crystallization consequently. Specifically, the thioester was synthesized in a one-pot procedure: an aromatic bromide (hexabromotriphenylene) reacted with excess sodium thiomethoxide under vigorous conditions to first form the thioether intermediate product. The thioether was then demethylated by the excess thiomethoxide to provide the thiolate anion that was acylated to form the thioester product. The thioester was conveniently purified by standard column chromatography, and then used directly in the framework synthesis, wherein NaOH and ethylenediamine serve to revert in situ the thioester to the thiol linker for assembling the single-crystalline Pb(II)-dithiolene network. Compared with other methods for thiol synthesis (e.g., by cleaving alkyl thioether using sodium metal and liquid ammonia), the thioester synthesis here uses simple conditions and economical reagents. Moreover, the thioester product is stable and can be conveniently handled and stored. More importantly, in contrast to the generic difficulty in accessing crystalline metal-thiolate open frameworks, we demonstrate that using the thioester for in situ formation of the thiol linker greatly improves the crystallinity of the solid-state product. We intend to encourage broader research efforts on the technologically important metal-sulfur frameworks by disclosing the synthetic protocol for the thioester as well as the crystalline framework solid.

Dramatic improvement of stability by in situ linker cyclization of a metal-organic framework.

We employ a two-step strategy for accessing crystalline porous covalent networks of highly conjugated π-electron systems. For this, we first assembled a crystalline metal-organic framework (MOF) precursor based on Zr(iv) ions and a linear dicarboxyl linker molecule featuring backfolded, highly unsaturated alkyne backbones; massive thermocyclization of the organic linkers was then triggered to install highly conjugated, fused-aromatic bridges throughout the MOF scaffold while preserving the crystalline order. The formation of cyclized carbon links not only greatly strengthens the precursor coordination scaffold, but also, more importantly, enhances electroactivity and charge transport throughout the polycyclic aromatic grid.

A fast-response fluorescent probe for hypochlorous acid detection and its application in exogenous and endogenous HOCl imaging of living cells.

A facile fluorescent probe (NBD-DOP) has been developed to detect hypochlorous acid (HOCl) in this study. The probe consists of a NBD fluorophore and a dopamine moiety that reacts with HOCl specifically. The dopamine group quenches the fluorescence of NBD efficiently through a photoinduced electron transfer (PET) effect. Experimental data showed that NBD-DOP could detect HOCl with ultrafast response, high sensitivity and high selectivity in a wide pH range. The probe could also be used to detect the myeloperoxidase enzyme that produces HOCl. Moreover, NBD-DOP has been applied in the imaging of exogenous and endogenous HOCl in living cells by confocal fluorescence microscopy.

A reaction-based near-infrared fluorescent sensor for Cu2+ detection in aqueous buffer and its application in living cells and tissues imaging.

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.

Construction of an alkaline phosphatase-specific two-photon probe and its imaging application in living cells and tissues.

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.

General survey of traditional Chinese medicine and Western medicine researches on tumor metastasis.

Metastasis and recurrence of tumors is the chief cause of death for such patients. Therefore, researches on the mechanism of its metastasis, prevention and treatment are the focal points in the field of traditional Chinese medicine (TCM) and Western medicine (WM) at present. WM practitioners' study on tumor metastasis involved its occurrence and development including every detail and process, and now it even has developed into the molecular biological field. In treatment surgical operation and radio-chemotherapy is used as the main means, but the efficacy is not too optimistic. In recent years, TCM, as part of the comprehensive therapy, has been gradually gaining attention of oncologists. Aimed at solving the difficult problems in metastasis of tumor, many TCM practitioners on the basis of syndrome differentiation have raised theories about the cause of tumor metastasis. On the basis of these theories, some TCM recipes against tumor metastasis have been developed to serve as an effective supplement to surgical operation, radio- and chemotherapy. The present article summarizes research results in recent years about the cause of formation of tumor and its metastasis by TCM and WM, so as to offer some theoretical clues to the study of tumor's metastasis.