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The adjustment of crystal symmetry and intramolecular magnetic coupling is of great importance for the construction of high-performance single-molecule magnets. By using an aggregation-induced-emission-active pyridine-carbohydrazone-based Schiff base ligand and phosphine oxides, four dinuclear and one one-dimensional DyIII-based complexes, [Dy2(TPE-pc)2(Bu3PO)2Cl2]·2CH3CN·2H2O (1), [Dy2(TPE-pc)2(Cy3PO)2Cl2] (2), [Dy2(TPE-pc)2(MePA)2Cl2]·2CH3OH (3), [Dy2(TPE-pc)2(Ph3PO)2Cl2]2 (4) and [Dy2(TPE-pc)2(DPPO)Cl2]n (5) (H2TPE-pc = (E)-N′-(2-hydroxy-5-(1,2,2-triphenylvinyl)benzylidene)picolinohydrazide, MePA = N-phenyl-N′,N′′-bis(morpholinyl) phosphoric triamide, DPPO = piperazine-1,4-diylbis(diphenyl phosphine oxide)), were isolated. All complexes are made up of an enol oxygen-bridged Dy2 unit, where DyIII ions possess a pentagonal bipyramidal geometry with pseudo D5h symmetry. Magnetic measurements reveal that intramolecular DyIII–DyIII couplings are ferromagnetic and all complexes display a significant slow magnetic relaxation phenomenon below 30 K under a zero dc field. Ab initio calculations indicate that the anisotropic magnetic axes of all DyIII ions are approximately perpendicular to the higher-order symmetric axes in all complexes, and that DyIII–DyIII magnetic couplings along the magnetic axes effectively suppress the ground state quantum tunneling effect of magnetization and promote the occurrence of slow magnetic relaxation. Raman relaxation prevails in all complexes. In addition, the H2TPE-pc ligand shows an aggregation-induced emission (AIE) effect; however, all complexes exhibit an aggregation-caused quenching (ACQ) phenomenon. [ABSTRACT FROM AUTHOR]

Diabetes is a chronic disease affecting 10% of the population globally, and can lead to serious damage in the heart, kidneys, eyes, blood vessels or nerves. Commercial artificial closed-loop feedback systems can significantly improve diabetes management and save lives. However, they are large and expensive for users. Here, we demonstrate for the first time a wearable, minimally-invasive, fully electrochemically-controlled feedback minisystem for diabetes management. Both the working principles of the sensor and pump in the feedback system are based on electrochemical reactions. The smart minisystem was constructed based on integrating the thermoplastic polyurethane hollow microneedles with an electrochemical biosensing device on its outer layer and an electrochemical micropump facing the inner layer of the microneedles. The sensing device was constructed based on sputtering thin metal films through a shadow mask and electroplating Prussian blue on the surface of the microneedles, followed by the immobilization of glucose oxidase on the working electrode. The electrochemical micropump was constructed by sputtering the interdigital electrodes, followed by sealing with a thin elastic film, which was further integrated with the inner channels of the microneedles. Both the sensor and the pump were electrically powered. Via being controlled by a printed circuit board, the biosensing device monitored the levels of interstitial glucose continuously to drive the electrochemical pump to deliver insulin intelligently, in order to control blood glucose within the normal range. The closed-loop feedback system was studied for its capability in maintaining the blood glucose levels of diabetic rats under various physiological conditions. The utility of the intelligent feedback system was successfully demonstrated on diabetic rats for controlling the blood glucose levels within the normal range. The minisystem is wearable, small, cost-effective, precise, stable and painless. It is anticipated that this approach opens a new paradigm for the development of closed-loop diabetes minisystems and may lead to a compelling future for diabetes management. [ABSTRACT FROM AUTHOR]

A green and practical photoinduced method for regioselective hydroboration of electron-deficient alkenes with NHC-borane has been developed in which 1,2-diphenyldisulfane was employed as a photocatalyst and hydrogen atom transfer (HAT) reagent precursor. This mild protocol shows excellent selectivity, good functional group tolerance, and broad substrate scope. A series of borylated carbonyl, nitrile, sulfone, phosphonate, trifluoromethyl, and gem-diboron compounds have been synthesized in moderate to excellent yields. [ABSTRACT FROM AUTHOR]

Despite the recent development of boryl radical reactions, current methods to generate them by relying on photocatalysts or radical initiators cause contamination of the reaction. Herein, a novel system for generating boryl radicals has been developed without using photocatalysts or external radical initiators, and only a catalytic amount of thiol has been used. The success of this approach depends on the dual role of thiol as a proton donor and hydrogen atom transfer (HAT) catalyst. The thiol first reacts with NHC-borane to give boryl sulphides via a dehydrocoupling reaction, and then they undergo in situ cleavage of their B–S bond through photochemical reactions. The radicals obtained were later involved in a fast thiol-catalyzed HAT reaction, affording the hydroboration products. This strategy enables the regioselective hydroboration for scalable synthesis of α- or β-borylated products from many kinds of α,β-unsaturated alkenes and styrenes in good to excellent yields, with broad functional group compatibility at room temperature. The reaction could also be extended to radical-type nucleophilic addition to imines. This unprecedented protocol is anticipated to find potential application in other boryl radical-involved reactions by using boryl sulphides through photochemical reactions. [ABSTRACT FROM AUTHOR]

The Schottky barrier height (ESBH) is a crucial factor in determining the transport properties of semiconductor materials and it directly regulates the carrier mobility in opto-electronics devices. In principle, van der Waals (vdW) Janus heterostructures offer an appealing avenue for controlling the ESBH. However, the underlying atomistic mechanisms are far from understood conclusively, which prompts further research in the topic. To this end, here we carry out an extensive first-principles study of the electronic properties and ESHB of several vdW Janus MXY/graphene (M = Mo, W; X, Y = S, Se, Te) heterostructures. The results of the simulations show that by changing the composition and geometry of the heterostructure's interface, it is possible to control its electrical contact, and thence electron transport properties, from ohmic to Schottky with up to a factor seven variation in the ESBH. Detailed analysis of the simulations enables rationalization of this highly attractive property on the basis of the interplay between the permanent dipole moment of the Janus MXY sheet and the induced one due to interfacial charge redistribution at the MXY/Gr interface. Such an interplay is shown to be highly effective in altering the electrostatic potential difference across the vdW Janus heterostructure, determining its ESBH, and thence Schottky (ohmic) contact type. These computational findings contribute guidelines to control the electrical contacts in Janus heterostructures towards the rational design of electrical contacts in nanoscale devices. [ABSTRACT FROM AUTHOR]

Understanding the mechanism of electrocatalytic reaction is important for the design and development of highly efficient electrocatalysts for energy technology. Investigating the surface structures of electrocatalysts and the surface processes in electrocatalytic reactions at the atomic and molecular scale is helpful to identify the catalytic role of active sites and further promotes the development of emerging electrocatalysts. Since it was invented, scanning tunnelling microscopy (STM) has become a powerful technique to investigate surface topographies and electronic properties at the nanoscale resolution. STM can be operated in diversified environments. Electrochemical STM can be used to investigate the surface processes during electrochemical reactions. Moreover, the critical intermediates in catalysis on catalyst surfaces can be identified by STM at low temperature or ultrahigh vacuum. STM has been extensively utilized in electrocatalysis research, including the structure–activity relationship of electrocatalysts, the distribution of active sites, and surface processes in electrocatalytic reactions. In this review, progress in the application of STM in electrocatalysis is systematically discussed. The construction of model electrocatalysts and electrocatalytic systems are summarized. Then, we present the STM investigation of electrocatalyst structures and surface processes related to electrocatalysis. Challenges and future developments in the field are discussed in the outlook. [ABSTRACT FROM AUTHOR]

Here, a photocatalytic deoxygenative amidation protocol using readily available amine-boranes and carboxylic acids is described. This approach features mild conditions, moderate-to-good yields, easy scale-up, and up to 62 examples of functionalized amides with diverse substituents. The synthetic robustness of this method was also demonstrated by its application in the late-stage functionalization of several pharmaceutical molecules. [ABSTRACT FROM AUTHOR]

Herein, we developed an enantioselective addition of aliphatic aldehydes to 2-hydroxychalcone promoted by cooperative organocatalysts, giving access to hybrid flavonoids in excellent enantioselectivities. This reaction took advantage of cycloisomerization of 2-hydroxychalcone to form a transient flavylium under the irradiation of 24 W CFL, which was trapped by the in situ generated chiral enamine intermediate. The synergistic action of chiral phosphoric acid secured the excellent outcome of this reaction by ion-pairing with the transient flavylium. [ABSTRACT FROM AUTHOR]

Herein, we report a tandem cycloisomerization/nucleophilic addition/cyclization of 2-amino chalcone with bifunctional nucleophiles driven by visible light. This cascade process is realized by the irradiation of a blue LED at room temperature, which provides a concise route to structurally diverse benzo[d][1,3]oxazocine scaffolds. Mechanistic studies show that the reaction is initiated with the E to Z isomerization of a C–C double bond upon the irradiation of visible light, followed by cyclization/rearomatization to generate a transient quinolinium intermediate, which is trapped by the nucleophile and cyclized to produce the polycyclic benzo[d][1,3]oxazocine. [ABSTRACT FROM AUTHOR]

In this study, we have constructed a binary supramolecular nanoassembly composed of α-cyclodextrin-modified hyaluronic acid and an azobenzene-modified diphenylalanine derivative with a positively charged imidazole group. This nanoassembly can bind with siRNA through electrostatic interactions and efficiently delivered them into cancer cells and inhibited their growth. [ABSTRACT FROM AUTHOR]

In this study, a green and atom economical strategy has been developed to construct polybismaleimide-based microporous organic polymers (BMOPs). The preparation is achieved through one-step thermal-initiation homopolymerization of individual bismaleimide monomers in diphenyl sulfone (DPS). During the polymerization, neither an initiator is needed nor are by-products formed. The obtained BMOPs demonstrate a defined molecular structure, a high BET surface area (1025 m2 g−1), excellent thermal/chemical stability, and good gas storage and capture performance (CO2: 13.25 wt%, 273 K/1.0 bar; CO2/N2 selectivity: 65.44, 273 K; H2: 1.05 wt%, 77.3 K/1.13 bar; CH4: 0.64 mmol g−1, 273 K/1.13 bar; five kinds of volatile organic compounds: 860–2480 mg g−1, room temperature). Moreover, DPS can be effectively recovered with a yield up to 95% and recycled at least three times. The characteristics of a predictable molecular structure and green and atom economical process endow this strategy with a potential applicability for sustainable and large-scale preparation of functional microporous organic polymers for industrial practice. [ABSTRACT FROM AUTHOR]

A green and sustainable preparation strategy is critical for the practical applications of microporous organic polymers (MOPs). Here, a new heteropoly acid catalyst/crosslinker system is adopted to prepare a new family of asphalt-based MOPs with a high surface area. In comparison with the conventional Friedel–Crafts hyper-cross-link polymerization, corrosive gases are completely avoided and the employed heteropoly acid catalyst can be recovered with yield up to 95% and recycled at least 9 times, retaining high catalytic performance. Particularly, the low cost, environmentally hazardous asphalt is converted into safe crosslinked polymers with good gas absorption capability. This “killing two birds with one stone” strategy is meaningful for the future industrial practice. [ABSTRACT FROM AUTHOR]

A novel MOF formulated as [Dy2(abtc)(H2O)2(OH)2]·2H2O (H4abtc = 3,3′,5,5′-azobenzene tetracarboxylic acid) was successfully synthesized, in which a dye-like ligand was integrated as a photosensitizer into MOFs by the reaction with Dy3+ ions (dye-based Dy-MOF). The ultra-stable dye-based Dy-MOF possesses a HOMO–LUMO gap of 2.17 eV as determined by UV-vis spectrum with absorbed edge at 570 nm. The dye-based Dy-MOF shows high catalytic activity for the UV-vis light driven hydrogen production, attributed to the porous structure and light harvesting from the dye-like ligand. The band-edge positions of the crystals of the dye-based Dy-MOF were studied via cyclic voltammetry (CV) to further verify the principle of photocatalytic hydrogen production. Furthermore, the exceptional thermal and pH stability of the dye-based Dy-MOF makes it possible to use them as photocatalysts in water. On using Pt cocatalyst, the UV-vis light photocatalytic hydrogen evolution rate of the dye-based Dy-MOF reaches 21.53 μmol h−1 g−1. In addition, the as-prepared dye-based Dy-MOF materials also exhibited good stability and recycling performance. [ABSTRACT FROM AUTHOR]

This article highlights the utilization of phosphorescent iridium(iii) complexes for biosensing and photodynamic therapy. Comments on the effectiveness of these complexes in biological applications are included. Challenges and potential solutions are also discussed for further development and exploitation. [ABSTRACT FROM AUTHOR]

The tin-oxo cage ([R12Sn12O14(OH)6]2+) is an excellent photoresist candidate in extreme ultraviolet lithography (EUVL). Photoionization that leads to plenty of photoelectrons and secondary electrons is an inevitable process upon irradiation by EUV light. The secondary electrons could cause electron blur and decrease the resolution of the photoresist. The utilization and improvement are limited owing to its poorly understood fundamental chemical process, such as exposure to EUV. In this study, the property of complexes (bare cage, binary complexes, and ternary complexes) formed by the combination of the cage and different counterions (methanesulfonate, tosylate, and triflate) was explored using density functional theory (DFT). Extended transition state-nature orbital of chemical valence (ETS-NOCV), charge decomposition analysis (CDA), and atomic dipole moment corrected Hirshfeld (ADCH) atomic charge analyses were carried out to characterize the interaction process (including ionization, electron attachment, and cleavage of the carbon–tin bond) and inherent mechanism. The number and species of counterions are closely associated with ionization and electron attachment; however, they show an inconspicuous effect on the carbon–tin bond energy. Meanwhile, tin free radical could be the reactivity site of ionization (and electron affinity). The activity of radical species is affected by counterions; this could be attributed to the changes in the charge density by diverse counterions, which could be an important factor in why the counterion affects the pattern. In addition, a superb linearity between the ADCH of tin free radical and IP/AP was found, which indicate that the atomic charge could be a simple and reliable substitution of complicated calculation for IP (or AP) to screen suitable counterions and improve the resolution of photoresist. [ABSTRACT FROM AUTHOR]

A luminescent nanoprobe has been designed for detection of oxygen. The nanoprobe exhibits high sensitivity, selectivity and excellent reversibility, and has been employed for hypoxia imaging in vitro and in vivo by ratiometric and photoluminescence lifetime imaging techniques. [ABSTRACT FROM AUTHOR]

In order to obtain multifunctional molecular-based materials, especially multiferroics, a polar structure is essential. In this study, we find that intelligently using the K+ cation can effectively achieve this goal in the Tb3+-croconate hybrid system. Four rationally designed complexes based on Tb3+ and croconic acid have been synthesized and structurally characterized. The complexes have the formula [Tb2(C5O5)3(H2O)12]·2H2O (1), [KTb(C5O5)2(H2O)6]·1.5H2O (2), [Tb(C5O5)(Hdpa)(H2O)5]·H2O (3) and [KTb(C5O5)2(H2O)5]·2H2O (4), (H2C5O5 = croconic acid, H2dpa = 2,5-dipicolinic acid). The structures of the complexes were remarkably different after K+ was introduced. Complex 1, constructed by eight-coordinate Tb3+ nodes connected with C5O52− and H2O, is a novel 0D metal–organic architecture with abundant O–H…O hydrogen bonds, whereas complex 2 is a 1D chain built by C5O52− spacers bridging five-coordinate K+ and eight-coordinate Tb3+ ions. Complex 3 has deprotonated C5O52− and Hdpa− anions connected to an eight-coordinate Tb3+ center, to give a polar 0D structure. Complex 4, constructed by nine-coordinate Tb3+ and ten-coordinate K+ nodes connected with C5O52− and H2O, is a novel, polar 3D metal–organic architecture. The fluorescence spectra of 1–4 show characteristic emission bands of Tb3+ ions. Interestingly, the fluorescence intensities of complexes 3 and 4, especially emissions at 370 nm, are significantly enhanced compared to the intensities of 1 and 2, owing to the structural differences. Magnetic susceptibility studies of complexes 1–4 show similar patterns. Furthermore, complex 4 exhibits a ferroelectric hysteresis loop at room temperature, due to its polarity. Thus, in this work, by merely adjusting the polarity of the structure, a series of different, versatile compounds were obtained as potential multifunctional materials. [ABSTRACT FROM AUTHOR]

MOFs with semiconducting behavior exhibit unique optoelectronic properties, and they are hailed as future low-bandgap materials, which are expected to serve as a new generation of functional materials to solve some thorny problems in the field of environment and energy. In this work, eight semiconducting MOFs with chemical formulae, {[Cd(m-bix)(ATP)]}n (1), {[Zn2(m-bix)(ATP)2]·DMF}n (2), {[Cd(m-bix)(BDC)(H2O)]}n (3), {[Co2(m-bix)(BDC)2(H2O)3]·2H2O·CH3OH}n (4), {[Ni2(m-bix)(BDC)2(H2O)3]·2H2O·CH3OH}n (5), {[Cd(m-bix)(Cl)]}n (6), {[Zn(m-bix)(CO3)]}n (7), and {[Cd(FDC)(H2O)3]·2H2O}n (8) (m-bix = m-bis(imidazol-1-ylmethyl)benzene; H2ATP = 2-aminoterephthalic acid; H2BDC = p-phthalic acid; H2FDC = 2,5-furandicarboxylic acid), were successfully synthesized by hydrothermal techniques. Comprehensive characterization of the as-synthesized MOFs showed that they display interesting topologies and fascinating structures (of 6 and 8 being 1D, 1, 2, 3, and 7 being 2D and 4 and 5 being 3D). The incorporation of π-conjugated ligands and abundant intermolecular hydrogen bonds endows these MOFs with higher carrier transport rates, resulting in unique optoelectronic properties. The optical band gaps of MOFs 1–8 obtained by UV reflection spectroscopy were 2.86, 2.59, 3.91, 3.01, 3.69, 3.19, 3.09, and 3.87 eV, respectively, proving that they are all potential semiconductor materials. Electrochemical oxygen evolution reaction (OER) catalysis studies revealed that MOFs 4–5 are efficient catalysts for the OER process with lower overpotentials of 381 and 397 mV at 10 mA cm−2 and lower Tafel slopes of 75.1 and 74.4 mV dec−1. Photoluminescence studies demonstrated that the Cd-based and Zn-based MOFs, especially MOF 2, exhibit strong violet light emission properties in the range of 405–446 nm, which are expected to be used in the development of new luminescent materials. In addition, the photocatalytic performance of these MOFs was evaluated. Among them, the best photocatalytic performance of 4 and 6 was attributed to the combination of the band gap value and luminescence performance, resulting in more photogenerated carriers and thus more catalytically active sites. This work not only provides a certain theoretical and experimental basis for further research on the optoelectronic properties of MOFs, but also affords an advanced strategy for the development of novel multifunctional materials to solve real-life environmental and energy problems. [ABSTRACT FROM AUTHOR]

In order to solve the problems of environmental pollution and energy crisis, it is of great significance to develop low-cost, high-efficiency and environmentally friendly multifunctional materials to deal with environmental and energy concerns. Herein, two multifunctional Cu(II) coordination complexes with the formula {[Cu(m-bix)(FDC)(H2O)]·H2O}n (1) and {[Cu2(DAP)4(NIP)2]·DMF}n (2) (m-bix = m-bis(imidazol-1-ylmethyl)benzene; DAP = N-(4-pyridyl)dimethylamine; H2FDC = 2,5-furandicarboxylic acid; H2NIP = 5-nitroisophthalic acid) were successfully constructed by using mixed ligands via a solvothermal method. Structural analyses show that both complexes exhibit a 1D chain structure, extending into a 3D supramolecular network via abundant hydrogen bonding forces. Electrochemical oxygen evolution reaction (OER) catalytic studies reveal that 1 and 2 are efficient electrocatalysts for the OER. In particular, 2 has a lower overpotential of 360 mV at 1 mA cm−2 under alkaline conditions. Furthermore, both complexes exhibit excellent photocatalytic activity due to their narrow band gaps – 2.51 eV (494 nm) for 1 and 2.77 eV (448 nm) for 2. The oxidation system composed of the complex and H2O2 can degrade methyl orange azo dyes (40 mg L−1) to less than 10% in only 150 minutes under sunlight irradiation. This work demonstrates that employing mixed ligands is a promising approach to obtain multifunctional complexes. It also opens up a unique path for the development of high-efficiency, low-cost, and environmentally friendly multifunctional materials to address environmental and energy issues. [ABSTRACT FROM AUTHOR]

To synthesize lead-free primary explosives with good thermal stability, pyridine-2-carbohydrazide (2-PDCA) was used to prepare a novel energetic copper perchlorate complex (ECCs-1), which was structurally characterized by infrared spectroscopy, NMR, and elemental analysis. Its thermal decomposition properties were investigated by thermogravimetry and a synchrotron thermal analyzer, and the sensitivity was tested by the BAM method. The laser ignition experiment and the lead plate tests show that the ECCs-1 complex has a good detonation performance with a high thermal decomposition temperature (215.6 °C) and moderate sensitivity (impact sensitivity = 3 J and friction sensitivity = 5 N). [ABSTRACT FROM AUTHOR]

A novel microplate-compatible chemiluminescence (CL) immunoassay has been developed for the determination of human immunoglobulin G (IgG) based on the luminol–AgNO3–gold nanoparticles CL system. Polystyrene microtiter plates were used for both immunoreactions and CL measurements. The primary antibody, goat-anti-human IgG, was first immobilized on polystyrene microwells. Then the antigen (human IgG) and the gold-labeled second antibody were connected to the microwells successively to form a sandwich-type immunocomplex. The gold label could trigger the reaction between luminol and AgNO3, accompanied by light emission. Under the optimized conditions, the CL intensity of the system was linear with the logarithm of the concentration of human IgG in the range from 25 to 5000 ng mL−1, with a detection limit of 12.8 ng mL−1(∼80 pM) at a signal to noise ratio of three (S/N= 3). Compared with other reported CL immunoassay method based on gold labels, the proposed CL protocol avoids a strict stripping procedure or difficult to control synthesis processes, making the method more simple, time-saving and easily automated. The present CL method is promising for the determination of clinically important bioactive analytes. [ABSTRACT FROM AUTHOR]

We report herein a series of quinoline-4-carboxylic acid linked COFs via the multicomponent one-pot in situ Doebner reaction. The obtained acid–base bifunctional COFs are chemically stable and can highly promote one-pot cascade deacetalization–Knoevenagel condensation reaction in a heterogeneous way under solvent-free conditions. [ABSTRACT FROM AUTHOR]

Precise and accurate determination of major components in alkali silicate glasses provides critical information concerning element distribution, petrogenesis and magmatic evolution. However, as one of the most important in situ microanalytical technologies, the application of electron probe microanalysis (EPMA) was limited by the time-dependent loss of X-ray intensity of alkali ions (especially Na) during electron beam bombardment on alkali silicate glasses. In this study, an optimized analytical method was developed using a JEOL JXA 8100 EPMA, aiming to get a long enough incubation duration suitable for accurate analysis of major element mass fractions. The optimal analytical conditions were determined as follows: 15 kV accelerating voltage, 2 nA beam current, 20 μm beam diameter, 40 s peak counting time, Na and K analyzed with top priority, time-saving mode with no additional detector movement and no peak search functioned. The availability of this low beam current density condition (6.37 × 10−3 nA μm−2) to 24 anhydrous reference glasses, with their compositions covering the entire spectrum from the ultramafic to highly siliceous range, was verified by the good agreement of the EPMA measured data with their GeoReM preferred values. Similarly, the methodology presented here is also suitable for analysis of hydrous glasses with H2O contents up to approximately 9 wt%, accompanied by no obvious Na loss found and no complicated mathematical corrections needed, and therefore can be used for the estimation of H2O contents in H2O-rich (>1 wt%) geological glasses by the difference method. Despite its analytical accuracy and precision (>0.5 wt%) not better than those of SIMS and FTIR, EPMA can be used as a substitute technique for H2O determination with its main advantages of excellent spatial resolution (down to 5–10 μm) and analytical convenience, especially for small melt inclusions or tiny experimental quench products, and the case with no appropriate calibration standards or no reported extinction coefficients available for those compositions of interest. In daily application, our optimized method is low cost and easy to implement and can achieve comparable precision and detection limits with acceptable efficiency (∼4–5 min/point for ten major elements) relative to routine analysis conditions. [ABSTRACT FROM AUTHOR]

Photomechanical crystals are promising candidates for photo actuators due to their ability to convert light energy into mechanical energy. We synthesized a coordination polymer crystal that can undergo [4 + 4] cycloaddition reactions with mechanical motion. The inclusion of {[ZnL2(4,4′-bipy)(CH3OH)2]}∞ in a polymer membrane significantly magnified the actuation behavior. [ABSTRACT FROM AUTHOR]

Building metal–organic frameworks (MOFs) covalently modified by onium halides is a promising approach to develop efficient MOF-based heterogeneous catalysts for the cycloaddition of CO2 to epoxides (CCE) into cyclic carbonates. Herein, we report a novel zirconium-based MOF covalently modified by methyl pyridinium bromide, Zr6O4(OH)4(MPTDC)2.2(N-CH3-MPTDC)3.8Br3.8 ((Br−)CH3-Pyridinium-MOF-1), where MPTDC denotes 3-methyl-4-pyridin-4-yl-thieno[2,3-b] thiophene-2,5-dicarboxylate. The structure and composition of this complex were fully characterized with PXRD, NMR, XPS, TEM and so on. CO2 adsorption experiments show that (Br−)CH3-Pyridinium-MOF-1 has a higher affinity for CO2 than its electrically neutral precursor, which should be attributed to the fact that charging frameworks containing pyridinium salt have stronger polarization to CO2. (Br−)CH3-Pyridinium-MOF-1 integrated reactive Lewis acid sites and Br− nucleophilic anions and exhibited efficient catalytic activity for CCE under ambient pressure in the absence of co-catalysts and solvents. Furthermore, (Br−)CH3-Pyridinium-MOF-1 was recycled after five successive cycles without substantial loss in catalytic activity. The corresponding reaction mechanism also was speculated. [ABSTRACT FROM AUTHOR]

An efficient approach for the synthesis of 2,2-disubstituted indolin-3-ones is described. From readily accessible aryl hydrazines and allyloxyketones, 2,2-disubstituted indolin-3-ones could be obtained in good to excellent yields under mild reaction conditions via a cascade Fischer indolization/Claisen rearrangement process. This protocol provides a facile entry to 2,2-disubstituted indolin-3-ones, which have been applied in the construction of the benzofuroindoline framework related to Phalarine. [ABSTRACT FROM AUTHOR]

Dextran modified with pendant acetals is used to load doxorubicin (DOX) and a near-infrared-emissive conjugated polymer (BTTPF), and this aims to provide selective drug release at therapeutic targets including tumors. The BTTPF is applicable to tracking the anticancer drug release through the change of Förster resonance energy transfer efficiency between doxorubicin and BTTPF during degradation of the nanoparticles in vivo. [ABSTRACT FROM AUTHOR]

Low-molecular-weight (LMW) thiols are important small molecules that regulate or maintain redox homeostasis in physiological and pathological processes. Assessing the concentrations of LMW thiols in biological systems may provide valuable information regarding physiological processes and the early diagnosis of some diseases. Here, we developed a method to simultaneously determine the concentrations of multiple LWM thiols in single cells by chemical derivatization assisted liquid chromatography-mass spectrometry (LC-MS). In this method, we synthesized a pair of stable isotope reagents, N-(acridin-9-yl)-2-bromoacetamide (AYBA) and N-(1,2,3,4-[2H4]-acridin-9-yl)-2-bromoacetamide ([2H4]AYBA). AYBA was used to derivatize LWM thiols in human cervical cancer (HeLa) cells, while [2H4]AYBA was used to derivatize standard LWM thiols to prepare internal standards for the LC-MS method development. The proposed AYBA derivatization greatly enhanced the detection sensitivity of LWM thiols by LC-MS, and thereby achieved the simultaneous detection of multiple LWM thiols by LC-MS in ∼1000 HeLa cells. Finally, the developed method was successfully utilized for the quantitative analysis of multiple LWM thiols in a single HeLa cell and the content changes of LWM thiols in a single HeLa cell before and after oxidative stress treatment. Accordingly, six LMW thiols were detected, including cysteamine, cysteine, glutathione, homocysteine, hydrogen sulfide, and pantetheine. [ABSTRACT FROM AUTHOR]

PbSe nanotubes (NTs) were synthesized through a low cost, facile and green hydrothermal route in combination with the assistance of ascorbic acid. In the hydrothermal reaction process, Se nanowires were not only used as templates, but also as a Se ion source to provide Se precursors for the growth of PbSe NTs. The prepared tubular crystals with a cubic structure have a length of 1–6 μm and an average diameter of ∼120 nm. Experimental results show that the amount of ascorbic acid and Pb2+ concentration play important roles in the formation of PbSe NTs, and a possible growth mechanism of PbSe NTs has also been presented. Additionally, the photocatalytic activity of the PbSe NTs was investigated and the results establish that PbSe NTs, in the presence of H2O2, showed a high photodegradation efficiency for methylene blue (MB). A probable photocatalytic mechanism for PbSe NTs is also discussed. [ABSTRACT FROM AUTHOR]

Neutral conjugated tetraarylethenes OFn (n = 1–3) and the corresponding cationic conjugated oligoelectrolytes OFn+ (n = 1–3) with aggregation-induced emission activity have been designed and synthesized using geminal cross-coupling. OFn+ (n = 1–3) feature ion-induced emission in aqueous solution. They are used for lysosomal fluorescence imaging and tracing of lysosome events. [ABSTRACT FROM AUTHOR]

Determination of low-molecular-weight compounds by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has been a great challenge in the analytical research field. Here we developed a universal peptide-based derivatization (peptidylation) strategy for the sensitive analysis of low-molecular-weight compounds by MALDI-TOF-MS. Upon peptidylation, the molecular weights of target analytes increase, thus avoiding serious matrix ion interference in the low-molecular-weight region in MALDI-TOF-MS. Since peptides typically exhibit good signal response during MALDI-TOF-MS analysis, peptidylation endows high detection sensitivities of low-molecular-weight analytes. As a proof-of-concept, we analyzed low-molecular-weight compounds of aldehydes and thiols by the developed peptidylation strategy. Our results showed that aldehydes and thiols can be readily determined upon peptidylation, thus realizing the sensitive and efficient determination of low-molecular-weight compounds by MALDI-TOF-MS. Moreover, target analytes also can be unambiguously detected in biological samples using the peptidylation strategy. The established peptidylation strategy is a universal strategy and can be extended to the sensitive analysis of various low-molecular-weight compounds by MALDI-TOF-MS, which may be potentially used in areas such as metabolomics. [ABSTRACT FROM AUTHOR]

We developed a novel strategy by oxidation–derivatization combined mass spectrometry analysis for the determination of 5-hydroxymethylcytosine and 5-formylcytosine in both DNA and RNA. We reported the presence of 5-formylcytosine in RNA of mammals and found that ascorbic acid and hydroquinone can increase the oxidation of 5-methylcytosine to 5-hydroxymethylcytosine in DNA and RNA. [ABSTRACT FROM AUTHOR]

Ambient ionization techniques show good potential in rapid analysis of target compounds. However, a direct application of these ambient ionization techniques for the determination of analytes in a complex matrix is difficult due to the matrix interference and ion suppression. To resolve this problem, here we developed a strategy by coupling magnetic solid phase extraction (MSPE) with desorption corona beam ionization (DCBI)-mass spectrometry (MS). As a proof of concept, the pyrrole-coated Fe3O4 magnetic nanoparticles (Fe3O4@Ppy) were prepared and used for the extraction of antidepressants. After extraction, the Fe3O4@Ppy with trapped antidepressants was then directly subjected to DCBI-MS analysis with the aid of a homemade magnetic glass capillary. As the MSPE process is rapid and the direct DCBI-MS analysis does not need solvent desorption or chromatographic separation processes, the overall analysis can be completed within 3 min. The proposed MSPE-DCBI-MS method was then successfully used to determine antidepressants in human urine and plasma. The calibration curves were obtained in the range of 0.005–0.5 μg mL−1 for urine and 0.02–1 μg mL−1 for plasma with reasonable linearity (R2 ＞ 0.951). The limits of detection of three antidepressants were in the range of 0.2–1 ng mL−1 for urine and 2–5 ng mL−1 for plasma. Acceptable reproducibility for rapid analysis was achieved with relative standard deviations less than 19.1% and the relative recoveries were 85.2–118.7%. Taken together, the developed MSPE-DCBI-MS strategy offers a powerful capacity for rapid analysis of target compounds in a complex matrix, which would greatly expand the applications of ambient ionization techniques with plentiful magnetic sorbents. [ABSTRACT FROM AUTHOR]

We developed a strategy for non-targeted profiling of aldehyde-containing compounds by stable isotope labelling in combination with liquid chromatography–double neutral loss scan–mass spectrometry (SIL–LC–DNLS–MS) analysis. A pair of stable isotope labelling reagents (4-(2-(trimethylammonio)ethoxy)benzenaminium halide, 4-APC and d4-4-(2-(trimethylammonio)ethoxy)benzenaminium halide, 4-APC-d4) that can selectively label aldehyde-containing compounds were synthesized. The 4-APC and 4-APC-d4 labelled compounds were capable of generating two characteristic neutral fragments of 87 Da and 91 Da, respectively, under collision induced dissociation (CID). Therefore, double neutral loss scans were carried out simultaneously to record the signals of the potential aldehyde-containing compounds. In this respect, the aldehyde-containing compounds from two samples labelled with 4-APC and 4-APC-d4 were ionized at the same time but recorded separately by mass spectrometry. The peak pairs with characteristic mass differences (n× 4 Da) can be readily extracted from the DNLS spectra and assigned as potential aldehyde-containing candidates, which facilitates the identification of the target aldehydes. 4-APC and 4-APC-d4 labelling also dramatically increased detection sensitivities of the derivatives. Using the SIL–LC–DNLS–MS strategy, we successfully profiled the aldehyde-containing compounds in human urine and white wine. Our results showed that 16 and 19 potential aldehyde-containing compounds were discovered in human urine and white wine, respectively. In addition, 5 and 4 aldehyde-containing compounds in human urine and white wine were further identified by comparison with aldehyde standards. Altogether, SIL–LC–DNLS–MS demonstrated to be a promising approach in the identification and relative quantification of aldehyde-containing compounds from complex samples. [ABSTRACT FROM AUTHOR]

DNA methylation, catalyzed by methyltransferases, plays critical roles in various biological processes in both prokaryotes and eukaryotes. Bacterial DNA adenine methyltransferases (DAM) are associated with bacterial pathogenesis and essential for bacterial virulence and viability. Since mammals do not methylate DNA at adenine, bacterial DAM is considered to be a great candidate target for developing new therapeutics for diseases. In the current study, we developed a simple, rapid and highly sensitive fluorescence method for the detection of DAM based on exonuclease-aided signal amplification. In the proposed strategy, a liberated amplifier upon DAM methylation and Dpn I digestion of the substrate can hybridize with a reporter (FT) that contains a quencher (TAMRA) at the second base of the 3′ end and a fluorophore (FAM) at the fifth base. Upon hybridization, exonuclease III degrades the reporter in the formed duplex DNA from the 3′ end successively, releasing the fluorophore from the quencher and resulting in an intensive appearance of the fluorescent signal. The amplifier will hybridize with another reporter and enter a new cycle, which therefore can amplify the signal and dramatically increase the detection sensitivity even with an extremely low amount of amplifier. Using this strategy, the detection limit down to 0.0025 U mL−1 of DAM was achieved within a short assay time of 30 min. Furthermore, the assay was applied to evaluate endogenous DAM activity in E. coli cell at different growth stages as well as the effects of inhibitors on DAM activity. Given the attractive analytical performance, the sensing strategy may find many important applications in biomedical research and clinical diagnosis. [ABSTRACT FROM AUTHOR]

A rapid analysis method by coupling carbon nanotube film (CNTF) microextraction with desorption corona beam ionization (DCBI) was developed for the determination of Sudan dyes (I–IV) and Rhodamine B in chilli oil samples. Typically, CNTF was immersed into the diluted solution of chilli oil for extraction, which was then placed directly under the visible plasma beam tip of the DCBI source for desorption and ionization. Under optimized conditions, five dyes were simultaneously determined using this method. Results showed that the analytes were enriched by the CNTF through the π–π interactions, and the proposed method could significantly improve the sensitivities of these compounds, compared to the direct analysis by DCBI-MS/MS. The method with a linear range of 0.08–12.8 μg g−1 and good linear relationships (R2 ＞ 0.93) in a multiple reaction monitoring (MRM) mode was developed. Satisfactory reproducibility was achieved. Relative standard deviations (RSDs) were less than 20.0%. The recoveries ranged from 80.0 to 110.0%, and the limits of detection (LODs) were in the range of 1.4–21 ng g−1. Finally, the feasibility of the method was further exhibited by the determination of five illegal dyes in chilli powder. These results demonstrate that the proposed method consumes less time and solvent than conventional HPLC-based methods and avoids the contamination of chromatographic column and ion source from non-volatile oil. With the help of a 72-well shaker, multiple samples could be treated simultaneously, which ensures high throughput for the entire pretreatment process. In conclusion, it provides a rapid and high-throughput approach for the determination of such illicit additions in chilli products. [ABSTRACT FROM AUTHOR]

A novel in-syringe dispersive solid phase extraction (dSPE) system using electrospun silica fibers as adsorbents has been developed in the current work. A few milligrams of electrospun silica fibers were incubated in sample solution in the barrel of a syringe for microextraction assisted by vortex. Due to the benefit of dispersion and the high mass transfer rate of the sub-microscale electrospun silica fibers, the extraction equilibrium was achieved in a very short time (less than 1 min). Moreover, thanks to the long fibrous properties of electrospun fibers, the separation of the adsorbent from sample solution was easily achieved by pushing out the sample solution which therefore simplified the sample pretreatment procedure. Besides, the analytical throughput was largely increased by using a multi-syringe plate to perform the extraction experiment. The performance of the in-syringe dSPE device was evaluated by extraction of endogenous cytokinins from plant tissue samples based on the hydrophilic interaction. Six endogenous cytokinins in 20 mg of Oryza sativa L. (O. sativa) leaves were successfully determined under optimized conditions using in-syringe dSPE combined with liquid chromatography-mass spectrometry analysis. The results demonstrated that the in-syringe dSPE method was a rapid and high-throughput strategy for the extraction of target compounds, which has great potential in microscale sample pretreatment using electrospun fibers. [ABSTRACT FROM AUTHOR]

A simple, rapid and sensitive method based on magnetic solid phase extraction (MSPE) coupled with in situ derivatization (ISD) was developed for the determination of endogenous acidic phytohormones in rice leaves by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis. With this method, acidic phytohormones were extracted onto the surface of a TiO2/magnetic hollow mesoporous silica sphere (MHMSS) through hydrophilic interaction, and then in situ derivatization was performed by the subsequent addition of 3-bromoactonyltrimethylammonium bromide (BTA). Thus, the process integrated extraction, purification, and derivatization into one step. Additionally, the permanent positively charged moiety from BTA significantly improved the ionization efficiencies of the acidic phytohormones. Several parameters affecting the efficiencies of the extraction, derivatization, and desorption were evaluated. The signal intensities of acidic phytohormones increased by 2 to 481 fold after treatment with MSPE-ISD. Under the optimized conditions, several endogenous acidic phytohormones, including GA4, GA9, GA20, JA, IAA, and ABA, were identified and quantified in rice leaves by the MSPE-ISD method. The limits of detection (LODs) were in the range of 1.03–91.21 pg mL−1. The relative recoveries ranged from 71.6–112.8%, with the intra- and interday relative standard deviations (RSDs) being less than 14.9% and 16.2%, respectively. Taken together, the proposed method provides a novel approach of combining magnetic solid phase extraction and in situ derivatization for the highly sensitive determination of endogenous acidic phytohormones. [ABSTRACT FROM AUTHOR]

In the current study, we developed a facile strategy for the one-pot synthesis of an aptamer-based organic–silica hybrid monolithic capillary column. A 5′-SH-modified aptamer, specifically targeting doxorubicin, was covalently modified in the hybrid silica monolithic column by a sol–gel method combined with “thiol–ene” click reaction. The prepared monolithic column had good stability and permeability, large specific surface, and showed excellent selectivity towards chemotherapeutic anthracyclines of doxorubicin and epirubicin. In addition, the enantiomers of doxorubicin and epirubicin can be easily separated by aptamer-based affinity monolithic capillary liquid chromatography. Furthermore, doxorubicin and epirubicin spiked in serum and urine were also successfully determined, which suggested that the complex biological matrix had a negligible effect on the detection of doxorubicin and epirubicin. Finally, we quantified the concentration of epirubicin in the serum of breast cancer patients treated with epirubicin by intravenous injection. The developed analytical method is cost-effective and rapid, and biological samples can be directly analyzed without any tedious sample pretreatment, which is extremely useful for monitoring medicines in serum and urine for pharmacokinetic studies. [ABSTRACT FROM AUTHOR]

We developed a novel method for non-targeted screening of metabolites by high performance liquid chromatography-mass spectrometry with paired homologous double neutral loss scan mode after in vitro isotope labelling (IL-HPLC-PHDNL-MS). As a proof of concept, we investigated the carboxylic acid metabolite profiling in plant samples by the IL-HPLC-PHDNL-MS method. To this end, N,N-dimethylaminobutylamine (DMBA) and d4-N,N-dimethylaminobutylamine (d4-DMBA) were synthesized and utilized to label carboxylic acids. Our results show the MS response of carboxylic acids was enhanced by 20- to 40-fold after labelling. As for the IL-HPLC-PHDNL-MS analysis, DMBA and d4-DMBA labelled samples were mixed equally before MS analysis. Because the isotope labelled moieties (dimethylamino moiety, Me2N) of DMBA and d4-DMBA are easily ruptured and lost as neutral fragments (NL 45 and NL 49) under collision induced dissociation (CID), two neutral loss scans can be carried out simultaneously to record the signals of DMBA and d4-DMBA labelled samples, respectively. In this respect, the metabolites from two samples labelled with different isotope reagents are ionized at the same time but recorded separately by mass spectrometry, which can eliminate the MS response fluctuation and mutual interference. Using this method, six potential biomarkers involved in wounded tomato leaves were identified, and their structures were further elucidated by product ion scan and high resolution mass spectrometry analysis. Taken together, the IL-HPLC-PHDNL-MS method demonstrated good performance on the identification as well as relative quantification of metabolites with a carboxyl group in biological samples. [ABSTRACT FROM AUTHOR]

SiO2–TiO2 composite fibers, prepared by electrospinning, were successfully applied to the rapid enrichment of phosphopeptides using a lab-in-syringe approach for the first time. Because of their large surface area, mesoporous structure, extraordinary length and appropriate Lewis acidity, the as-prepared SiO2–TiO2 composite fibers exhibited high selectivity and capacity in the enrichment of phosphopeptides from the digestion mixture of β-casein and bovine serum albumin (BSA), as well as human blood serum and nonfat milk. The targeted phosphopeptides could be easily enriched and detected even when the total amount of β-casein was decreased to only 10 fmol, indicating the high detection sensitivity of this method. In addition, the whole enrichment extraction procedure can be finished in less than 3 min, which can avoid or decrease the degradation of endogenous phosphoproteins by proteases released ex vivo during time-consuming treatments. The developed method is rapid, cost-effective, selective, sensitive, operationally simple, and does not require any harsh conditions and intricate equipment, providing an ideal candidate for the enrichment of phosphopeptides from complex biological samples either in the lab or in the field. [ABSTRACT FROM AUTHOR]

In order to quantitatively study the jasmonate biosynthetic pathway, we chemically synthesized a pair of isotope mass probes and established a labeling protocol. The pair of mass probes used in our work were ω-bromoacetonylpyridinium bromide (BPB) and d5-ω-bromoacetonylpyridinium bromide (d5-BPB), which contain carboxylic acid reactive groups, isotopically labeled groups and permanent positive charges. High performance liquid chromatography (HPLC) and electrospray ionization quadrupole-time of flight mass spectrometry (ESI-QTOF-MS) were used for the detection of labeled standard mixtures and plant samples. In comparison to negative mode electrospray ionization detection of unlabeled analytes, the ESI signal of reverse charge labeled compounds was shown to improve by 20- to 80-fold. Accurate relative quantification was achieved as no isotopic effects of the different isotope labeled phytohormones during RP/SCX mixed-mode liquid chromatographic separation were observed. A data analysis method was established for analyzing metabolic pathways using our labeling strategy. We then applied our method and examined the jasmonate biosynthetic pathway of rice under salt stress and the premature senescence mutant. Here we found that under salt stress conditions, rice showed up-regulation in (13S)-hydroperoxyoctadecatrienoic acid (HOPT), cis-(+)-12-oxophytodienoic acid (OPDA), 3-oxo-2-(2′-pentenyl)-cyclopentane-1-octanoic acid (OPC-8) and jasmonoyl-valine (JA-Val) levels, while α-linolenic acid (LA) and jasmonic acid (JA) showed down-regulation, and three components (HPOT, OPC-8 and JA-Val) were accumulated. The premature senescence mutant showed up-regulation in all major components of the jasmonate biosynthetic pathway with the exception of LA, and an accumulation of HPOT, OPC-6 and JA-Val. This study demonstrates that our chemical stable isotope labeling strategy can be used as a powerful tool for metabolic pathway analysis of phytohormones in plants. [ABSTRACT FROM AUTHOR]

A MALDI-TOF mass spectrometric method for rapid screening of protein tyrosine kinase (PTK) inhibitors has been developed. To circumvent the ion suppression of phosphorylated substrate peptides caused by the presence of high abundant non-phosphorylated peptides in the enzymatic reaction mixtures, a separation and enrichment process of the phosphorylated peptides from complex mixtures was carried out by using an in-house fabricated TiO2nanoparticle-coated capillary column prior to the MS analysis. With a synthetic phosphopeptide (DAIpYAAPFAKKK), of which the sequence is similar to that of the substrate (EAIYAAPFAKKK) of the Abelson tyrosine kinase (Abl), as the internal standard, the signal ratio of the phosphorylated substrate to the standard detected by MALDI-TOF MS is linearly correlated with the molar ratio of the two phosphopeptides over the range of 0.3 to 3 with r2= 0.99. We validated the MS method by determining the IC50value of imatinib, an Abl inhibitor for clinical treatment of chronic myelogenous leukaemia (CML). The obtained IC50value (234 nM) is consistent with that determined by ELISA (291 nM). Then, six analogues of imatinib synthesized in our laboratory were screened using the method, giving rise to inhibitory potential results which are in good agreement with the docking analysis data. The developed method is sensitive, operationally simple, does not require isotope-labelling and is cost/time effective, providing an alterative method for rapid screening of PTK inhibitors as therapeutic agents for tumours. [ABSTRACT FROM AUTHOR]

A MALDI-TOF mass spectrometric method for rapid screening of protein tyrosine kinase (PTK) inhibitors has been developed. To circumvent the ion suppression of phosphorylated substrate peptides caused by the presence of high abundant non-phosphorylated peptides in the enzymatic reaction mixtures, a separation and enrichment process of the phosphorylated peptides from complex mixtures was carried out by using an in-house fabricated TiO2nanoparticle-coated capillary column prior to the MS analysis. With a synthetic phosphopeptide (DAIpYAAPFAKKK), of which the sequence is similar to that of the substrate (EAIYAAPFAKKK) of the Abelson tyrosine kinase (Abl), as the internal standard, the signal ratio of the phosphorylated substrate to the standard detected by MALDI-TOF MS is linearly correlated with the molar ratio of the two phosphopeptides over the range of 0.3 to 3 with r2= 0.99. We validated the MS method by determining the IC50value of imatinib, an Abl inhibitor for clinical treatment of chronic myelogenous leukaemia (CML). The obtained IC50value (234 nM) is consistent with that determined by ELISA (291 nM). Then, six analogues of imatinib synthesized in our laboratory were screened using the method, giving rise to inhibitory potential results which are in good agreement with the docking analysis data. The developed method is sensitive, operationally simple, does not require isotope-labelling and is cost/time effective, providing an alterative method for rapid screening of PTK inhibitors as therapeutic agents for tumours. [ABSTRACT FROM AUTHOR]

A novel boronate affinity monolith, poly(3-acrylamidophenylboronic acid-co-ethylene dimethacrylate) (AAPBA-co-EDMA), was prepared in 530 µm capillaries by a one-step in situpolymerization procedure using a pre-polymerization mixture consisting of functional monomer 3-acrylamidophenylboronic acid, cross-linker ethylene dimethacrylate, porogenic solvent methanol with added poly(ethylene glycol) 20 000 (PEG 20 000) and initiator azobisisobutyronitrile (AIBN). The preparation of the monolith was optimized by investigating the ratio of functional monomer to cross-linker and the effect of poly(ethylene glycol) molecular weight. The resulting boronate monolith was used as a sorbent for polymer monolith microextraction (PMME). Using nucleosides as the testing analyte, the extraction performance of this boronate monolith towards glycol-containing compounds was examined. Finally, the boronate monolith was applied for selective enrichment of glycopeptides and glycoproteins. [ABSTRACT FROM AUTHOR]

A novel method of polymer monolith microextraction (PMME) using a poly(acrylamide-vinylpyridine-N,N′-methylene bisacrylamide) (AA-VP-Bis) monolithic column combined with electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) for the determination of trace Cd, Tl, and Pb with Pd as chemical modifier has been proposed. Several factors that influence the microextraction efficiency including pH value, sample flow rate, extraction time, sample volume, eluent volume, and coexisting ions, were investigated and the optimal microextraction conditions were established. The chemical modification of Pd in ETV-ICP-MS has been studied and the results indicated that the pyrolysis temperature for the target analytes could be increased up to 600 °C and the signal intensities were increased by 4.1, 2.1, and 13.8 times for Cd, Tl, and Pb, respectively. Under the optimized conditions, with a consumption of 0.4 mL sample, the limits of detection (LODs) were 1.1, 0.5, and 0.2 ng L−1for Cd, Tl, and Pb, and the relative standard deviations (RSDs) were 10.3, 9.7, and 9.2% (C = 0.05 µg L−1, n = 5) for Cd, Tl, and Pb, respectively. The proposed method was successfully applied to the determination of trace Cd, Tl, and Pb in human serum and urine samples, and the recovery for the spiked samples were in the range of 90–110%. In order to validate the proposed method, certified reference material of GBW09103 human urine was analyzed, and the determined values were in good agreement with the certified values. The poly(AA-VP-Bis) monolith can be used more than 40 times without decrease in the extraction efficiency. [ABSTRACT FROM AUTHOR]

We demonstrate for the first time that a nitrogen-doped tunneled oxide MgTa2O6-xNx with an absorption edge of ca. 570 nm can drive both water oxidation and reduction half reactions in the presence of scavengers under visible light irradiation, showing great potential in solar water splitting. [ABSTRACT FROM AUTHOR]

A mild and efficient copper-catalyzed trifluoromethylation reaction which involves the cyclization of oximes has been developed. This method provides a convenient access to a variety of useful CF3-containing 4,5-dihydroisoxazoles by constructing a C–CF3 bond and a C–O bond in one step. [ABSTRACT FROM AUTHOR]

Titania coated magnetic hollow mesoporous silica spheres with high surface area were created, which can be used in efficient and rapid capture of phosphopeptides from peptide mixtures. [ABSTRACT FROM AUTHOR]