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Abstract: Like many branches of science, not to mention culture in general, electrochemistry has a number of recurring topics: Areas of research that are popular for a certain time, then fade away as their possibilities seem to have been exhausted, only to return decades later as progress in experimental or theoretical techniques offer new possibilities for their investigation. A prime example are fuel cells, which have undergone five such cycles, but here we discuss a general concept of kinetics—the pre‐exponential factor of a rate constant—which has undergone two such cycles. The first cycle was in the 1950–1980s, when the methods of electrochemical kinetics were developed, and the interpretation was based on transition‐state theory. The second was triggered by the re‐discovery of Kramers theory for reactions in condensed phases. This Minireview will show that the time has come for a third cycle based on recent progress in electrocatalysis. [ABSTRACT FROM AUTHOR]

The pentagonal bipyramidal single-ion magnets (SIMs) are among the most attractive prototypes of high-performance single-molecule magnets (SMMs). Here, a fluorescence-active phosphine oxide ligand CyPh2PO (=cyclohexyl(diphenyl)phosphine oxide) was introduced into [Dy(CyPh2PO)2(H2O)5]Br3⋅2 (CyPh2PO)⋅EtOH⋅3 H2O, and combined dynamic magnetic measurement, optical characterization, ab initio calculation, and magneto-optical correlation of this high-performance pseudo- D5 h DyIII SIM with large Ueff (508(2) K) and high magnetic hysteresis temperature (19 K) were performed. This work provides a deeper insight into the rational design of promising molecular magnets. [ABSTRACT FROM AUTHOR]

The organocatalytic asymmetric synthesis of hexahydropyridazines were performed through a unique Michael/amination/cyclization reaction. The organocascade reaction proceeded smoothly between 2-arylidene-1,3-indandiones and aldehydes followed by the addition of azodicarboxylates catalyzed by the privileged organocatalyst α,-α-L-diphenylprolinol trimethylsilyl ether (10 mol%) in the presence of a base additive Et3N (20 mo%) at 0 °C. A series of substituted hexahydropyridazines were obtained in good to high chemical yields (55-78 %) and reasonable to high levels of stereoselectivities (51-93 % ee and 4 : 1 d.r.). [ABSTRACT FROM AUTHOR]

In this work, we investigate the cycle-based optimal NO x emission control for Diesel engine selective catalytic reduction (SCR) systems. The optimization is carried out based on the SCR model and the SCR is assumed to be a continuous stirred tank reactor during the modeling. Considering the main chemical reactions inside an SCR cell, a three-state nonlinear model is obtained and the system parameters are determined by using the experimental data. The states of the nonlinear model consist of the NO x concentration, the ammonia concentration, and the ammonia coverage ratio. Though there are considerable works on the SCR dosing control in the literature, the optimal control strategy applied to the SCR systems has been rarely studied. The global optimality in the SCR dosing control can be used as a benchmark and evaluate the performance of other designed controllers. Moreover, it can be employed to find the limit of NO x conversion efficiency of a specific SCR aftertreatment system and select the minimal volume of the SCR catalyst cell. Therefore, it is quite meaningful to study the optimal NO x emission control of SCR systems via the dynamic programming approach. For the optimization, the challenges arise from the following aspects: (1) Due to the system stiffness, we cannot find an equivalent discrete-time model for the traditional dynamic programming, that is, the traditional dynamic programming algorithm is not applicable. (2) The computational load is relatively too heavy and a personal PC is not affordable. To deal with the existing challenges, we propose the dynamic programming algorithm based on the continuous-time SCR model. The computational load is adjustable in terms of the accuracy. The proposed algorithm is then applied to the SCR system for the NO x emission reduction. And the algorithm validation is carried out based on the US06 test cycle. It infers from the optimization results and the comparison, the prescribed ammonia slip constraint is satisfied and the tailpipe NO x emission is optimized. [ABSTRACT FROM AUTHOR]

A crude extract of earthworms was used as an eco-friendly, environmentally benign, and easily accessible biocatalyst for various organic synthesis including the asymmetric direct aldol and Mannich reactions, Henry and Biginelli reactions, direct three-component aza-Diels-Alder reactions for the synthesis of isoquinuclidines, and domino reactions for the synthesis of coumarins. Most of these reactions have never before seen in nature, and moderate to good enantioselectivities in aldol and Mannich reactions were obtained with this earthworm catalyst. The products can be obtained in preparatively useful yields, and the procedure does not require any additional cofactors or special equipment. This work provides an example of a practical way to use sustainable catalysts from nature. [ABSTRACT FROM AUTHOR]

The TbIII compound [Tb(tci)(H2O)] n · n(DMF) ( 1) [H3tci = tri(2-carboxythyl)isocyanurate, DMF = N,N′-dimethylformamide] was synthesized by the reaction of terbium oxide, H3tci, and two drops of concentrated nitric acid in the presence of DMF and H2O. Single crystal X-ray analysis reveals that it features a three-dimensional (3D) framework based on infinite -Tb-COO-Tb- chains. The tci ligand in 1 links six different TbIII ions with its two carboxylate groups in μ2-κ1O;κ2O,O′ mode and the third in μ2-κ1O;κ1O′ mode. Thermal analysis reveals that it remains high thermal stability until 390 °C. Luminescence investigation shows that it emits characteristic green light of TbIII ions. [ABSTRACT FROM AUTHOR]

[Display omitted] • A plant sorbent assisted mini-SPE method is proposed. • Novel microwave-induced activated carbons was utilized as the plant sorbent in this work. • Activated carbon was prepared by microwave chemical reaction from hawthorn leaves. • The approach was successfully applied in the extraction of multiple pesticide residues in Dendrobium officinale. A simple and green plant sorbent-based miniaturized solid phase extraction (mini-SPE) method was presented for the detection of multi-pesticide residues in Dendrobium officinale by ultra-high performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry. Activated carbons prepared from hawthorn leaves were used as a green sorbent in microwave (MW) assisted mini-SPE process. Various parameters such as the type and concentration of extraction solvent, MW time and MW temperature, were investigated in detail to obtain the optimum conditions in this procedure. Under the final optimized conditions, this method displayed a satisfactory linearity, with its correlation coefficients ranged from 0.9927 to 0.9991. The limits of detection ranged between 0.08 and 1.35 ng/mL for the seven pesticides. And the recoveries of the pesticides in Dendrobium officinale ranged from 81.17 to 106.12% at two spiked levels (0.05 and 5 ug/mL), indicating the accuracy of the proposed mini-SPE method was acceptable. Besides, the reproducibility of the method was satisfactory, with the RSDs lower than 0.37% for retention time, 3.72% for peak area, respectively. The proposed mini-SPE method was efficiently applied for the determination and extraction of the pesticides in Dendrobium officinale, thus demonstrating that this method was reliable. [ABSTRACT FROM AUTHOR]

A K2NiF4-type oxide (Nd0.9La0.1)2(Ni0.74Cu0.21Al0.05)O4+δ(NLNCA) has been successfully synthesizedby a sol–gel method. The oxygen permeation and stability ofthe NLNCA membrane under CO2atmosphere were systematicallystudied. A steady oxygen permeation flux of 0.39 mL/(min·cm2) was obtained through the NLNCA membrane with a membranethickness of 0.6 mm at 975 °C when CO2was used asthe sweep gas. More importantly, the oxygen permeation flux has nosignificant decrease during 250 h operation, which indicates thatthe NLNCA membrane is stable under CO2. X-ray diffractionanalysis of the spent membrane shows that the membrane retains K2NiF4-type structure and no carbonate was formedeven exposed to CO2after 250 h operation. The resultsindicate that the NLNCA membrane has a great potential applicationin supplying oxygen for oxyfuel combustion with CO2capture.Moreover, the cost of the NLNCA is low, and it is beneficial for industrialapplication. [ABSTRACT FROM AUTHOR]

A variety of N-substituted 3-aminocyclohex-2-enones were converted into the corresponding N-arylated ?-iodo enaminones in high yields via concurrent ?-iodination and N-arylation mediated by ArI(OAc) 2. A mechanism is postulated to account for the reaction differences between the cyclic and the acyclic ?-enamin?ones, which undergo predominant ?-acetoxylation under the same reaction conditions. [ABSTRACT FROM AUTHOR]

Abstract: Two series of raw materials were adopted to form TiAl/Ti2AlC composites: Ti/Al/TiC and Ti/Al/C. Differential thermal analysis (DTA) of starting powers and X-ray diffraction (XRD) of samples sintered at different temperatures from 600°C to 1300°C by hot pressing were utilized to analyze the phase transformation and the mechanism of synthesis. Scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS) was utilized to investigate the morphology characteristics of the products. The experimental results showed that Ti reacted with Al to form TiAl intermetallics below 900°C; and above 900°C, TiAl reacted with TiC to produce dense TiAl/Ti2AlC composites. The products sintered at 1200°C had fine crystals and dense fibres, and the distribution of Ti2AlC particles in TiAl matrix was homogeneous. [Copyright &y& Elsevier]

Abstract: Water-soluble sulfonated poly(diphenylamine) (SPDPA) was synthesized and applied as a hole injection layer (HIL). It was characterized in terms of 1H NMR, 13C NMR, elemental analysis (EA), UV–vis, Raman, ultraviolet photoelectron spectroscopies (UPS) and TGA thermal stability measurement. The high transparency in visible region and acceptable conductivity were beneficial as HIL material. The topographic image obtained from Atomic Force Microscope shows that the surface of SPDPA-coated indium tin oxide (ITO) is smoother than that of bare ITO. Raman spectra indicate that SPDPA possesses the higher oxidation and doping level due to SO3H group on the phenyl ring, rendering SPDPA the higher work function with 0.35eV than PDPA from UPS spectra. The electroluminescence efficiency of polymer light emitting diode using poly(2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene vinylene) (MEH–PPV) as an active layer and SPDPA as HIL can be reached 2.0cd/A, showing the slightly better performance than that using PEDOT:PSS as HIL. [Copyright &y& Elsevier]

Reactions of Pt(diimine)(tdt) (tdt = 3,4-toluenedithiolate) with [M2(dppm)2(MeCN)2]²+ (M = CuΙ or AgΙ, dppm = bis(diphenylphosphino)methane) gave heterotrinuclear complexes [PtCu2(tdt)(μ-SH)(dppm)3](CIO4)(1) and [PtCu2-(diimine)a(tdt)(dppm)2](CIO4)2 (diimine = 2,2′-byridine (bpy) 2; 4,4′-dimethyl-2,2′-bipyridine (dmbpy) 3; phenanthroline (phen) 4, 5-bromophenanthroline (Brphen) 5) for M - CuΙ, but [PtAg2(tdt)(μ-SH)(dppm)3](SbF6) (6) and [PtAg2(diimine)(tdt)(dppm)2](SbF6)2 (diimine = bpy 7; dmbpy 8; phen 9; Brphen 10) for M = AgΙ. While the complexes [PtAg2(diimine)(tdt)(dppm)2](SbF6)2 (7–10) result from linkage of Pt(diimine)(tdt) and [M2(dppm)2(MeCN)2]²+ by tdt sulfur donors, formation of [PtCu2(diimine)2(tdt)(dppm)2](ClO4)2 (2–5) is related to rupture of metal-ligand bonds in the metal components and recombination between the ligands and the metal atoms by self-assembly. The formation of 1 and 6 is involved not only in dissociation and recombination of the metal components, but also in disruption of C-S bonds in the dithiolate (tdt). The dithiolate tdt adopts a chelating and bridging coordination mode in anti conformation for [PtCu2(diimine)2(tdt)(dppm)2](CIO4)2 (2–5), whereas there is the syn conformation for other complexes. Compounds 1 and 6 represent sparse examples of μ-SH-bridged heterotrinuclear PtΙΙMΙ2 complexes, in which PtΙΙ-MΙ centers are bridged by dppm and sulfur donors of tdt, whereas MΙ-MΙ (M = Cu for 1; Ag for 6) centers are linked by dppm and the μ-SH donor. The 31P NMR spectra show typical platinum satellites (JPt-P = 1450–1570 Hz) for 1–6 and Ag-P coupling for PtΙΙ-AgΙ (JAg-P = 350–450 Hz) complexes 6–10. All of the complexes show intense emission in the solid state and in frozen glasses at 77 K. The complexes [PtAg2(diimine)(tdt)(dppm)2](SbF6)2 (7–10) also afford emission in fluid acetonitrile solutions at room temperature. Solid-state emission lifetimes at room temperature are in the microsecond range. It is revealed that emission energies of the trinuclear heterometallic complexes [PtAg2(diimine)(tdt)(dppm)2](SbF6)2 (7–10) exhibit a remarkable blue shift (0.10–0.35 eV) relative to those of the precursor compounds Pt(diimine)(tdt). The crystal structures of 1, 2, 4, 6, 8, and 9 were determined by X-ray crystallography. [ABSTRACT FROM AUTHOR]

Abstract The synergetic effects of chemical-mechanical interactions are key to generate atomically flat surfaces during polishing. The mechanisms need to be further understood. Here we report the influence of pH values on chemical-mechanical interactions during cobalt chemical-mechanical polishing (CMP). Using an in situ approach combining polishing and electrochemical measurement, we found that the single frequency electrochemical impendence Z value reflected the nature and thickness of the surface oxide. Specifically, the oxide thickness grew when the pH was increased from 5.0 to 8.0 and reduced while in 8.0–9.0. The variation of pH not only affected cobalt chemical reactions but also abrasive effects, along with mechanical input through contact pressure, as well as surface speed. It is interesting that the pH value affects both the chemical reaction and mechanical wear. Specifically, oxidation enhances with the increase in pH from 5.0 to 8.0 resulting in a thicker film. Subsequently the mechanical wear becomes stronger, over oxidation in the range of pH 8.0–9.0. As a result, the thickness of oxide is reduced. This investigation is beneficial to understanding metal CMP process and polishing mechanism. Highlights • The influences of pH values and mechanical power on chemical-mechanical interactions were studied in situ. • The variation of pH not only affected cobalt chemical reactions but also abrasive effects along with mechanical input. • Oxidation enhanced from pH 5.0 to 8.0 but the Mechanical abrasion became stronger in the range of pH 8.0- 9.0. [ABSTRACT FROM AUTHOR]

Achieving selective C−H activation at a single and strategic site in the presence of multiple C−H bonds can provide a powerful and generally useful retrosynthetic disconnection. In this context, a directing group serves as a compass to guide the transition metal to C−H bonds by using distance and geometry as powerful recognition parameters to distinguish between proximal and distal C−H bonds. However, the installation and removal of directing groups is a practical drawback. To improve the utility of this approach, one can seek solutions in three directions: 1) Simplifying the directing group, 2) using common functional groups or protecting groups as directing groups, and 3) attaching the directing group to substrates via a transient covalent bond to render the directing group catalytic. This Review describes the rational development of an extremely simple and yet broadly applicable directing group for PdII, RhIII, and RuII catalysts, namely the N-methoxy amide (CONHOMe) moiety. Through collective efforts in the community, a wide range of C−H activation transformations using this type of simple directing group have been developed. [ABSTRACT FROM AUTHOR]

A robust, high-throughput method using hydrophilic interaction liquid chromatography (HILIC) coupled with a charged aerosol detector (CAD) is reported as a novel approach for trisulfide quantitation in monoclonal antibodies (mAbs). The products of mAb reduction using tris (2-carboxyethyl)phosphine (TCEP) include a species (TCEP(S)) that is stoichiometrically produced from trisulfides. The TCEP reaction products are chromatographically separated, detected, and quantified by the HILIC CAD method. The method was qualified to quantify trisulfides across a range of 1–40% (mol trisulfide/mol mAb). In all tested matrix components, assay linearity and intermediate precision were established with correlation coefficients (R 2 ) > 0.99, and relative standard deviations (RSD) < 10%. A method comparability study was performed using peptide mapping LC–MS as an orthogonal measurement. For the range of 1–40% trisulfides, the analysis demonstrates that, on average, HILIC CAD reads between 0.95 and 1.10 times the value of LC–MS with 95% confidence. Applications of the HILIC CAD method include trisulfide determination in purified mAbs to be used in the production of cysteine-linked antibody-drug conjugates, and in cell culture development studies to understand sources of, and strategies for control of, trisulfides. [ABSTRACT FROM AUTHOR]

This contribution proposes an adiabatic criterion ( cri ad ) for online detection of thermal runaway region and determination of the real-time acceptable accumulation in a semibatch process. The cri ad is deduced based on a mathematic analysis of the mass and heat balance equations of semibatch reactors. It states that the semibatch processes are in a potential runaway situation if the value of cri ad is positive on a segment of the reaction path. Furthermore, the numerical simulations for semibatch second order reactions were performed under isoperibolic and isothermal operating conditions verify the validation of the cri ad . To take advantage of this criterion, the information on real-time temperature of the reaction mixture and conversion of the reactants are required. Specifically, the temperature of reaction mixture can be directly measured, while the conversion of the reactants can be online measured through a modified reaction calorimetry method. This criterion can potentially contribute to optimize the feeding profile as a safety constraint as well as enhance the inherent safety of the semibatch processes. [ABSTRACT FROM AUTHOR]

The ligands 2-pyrazol-1-yl-1H-indole (HL1) and 2-,,-triazol-1-yl-1H-indole (HL2) individually reacted with Ti(NMe2)4 in tetrahydrofuran to form the corresponding complexes Ti(L1)2(NMe2)2 ( 1) and Ti(L2)2(NMe2)2 ( 2), respectively. The titanium complexes were fully characterized by NMR measurement and elemental analysis as well as the single-crystal X-ray diffraction of 1 and 2. Both 1 and 2 exhibit high activities towards intermolecular hydroamination of terminal alkynes with high selectivity, and they also efficiently promote the ring-opening polymerization of ϵ-caprolactone. [ABSTRACT FROM AUTHOR]

ABSTRACT The synthesis of well-defined polystyrene by atom transfer radical polymerization (ATRP) is reported. The effects of temperature, initiators, catalysts, and ligands on styrene bulk ATRP were investigated in detail. Results indicated that the initiator activity for a given monomer needs careful matching to bring about a match of the chain-initiation and chain-propagation rates. The higher activity is not necessarily the better. Thus, the less reactive monomer, styrene, was efficiently initiated by 1-phenylethyl bromide (1-PEBr), which only has a moderate initiator activity. Similarly, the catalyst system had to be carefully matched to achieve a real controlled/living radical polymerization. Controlled/living bulk ATRP of styrene was achieved by using 1-PEBr as initiator, copper(I) bromide as catalyst, and N,N,N′,N′′,N′′- pentamethyldiethyllenetriamine as ligand at 90°C. After 4 h, the monomer conversion reached 51.8%, the practical molecular weight of polystyrene coincided well with the theoretical molecular weight of polystyrene, and the molecular weight distribution was 1.15. © 2013 Wiley Periodicals, Inc. Adv Polym Technol 2013, 32, 21371; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21371 [ABSTRACT FROM AUTHOR]

By means of multicomponent reactions, via Michael addition, nucleophilic addition, using nitenpyram, substituted aromatic aldehydes, and cyanoacetate compounds or propanedinitrile, a new series of cis-configuration nitenpyram analogs ( 1a-1k) were synthesized by introducing the 1,4-dihydropyridine scaffold pharmacophore, as shown in Scheme 1. The structures of all compounds were confirmed by IR, 1HNMR, 13C NMR, and elemental analysis. The preliminary bioassay showed that most of the target compounds exhibited good mortality against Aphis craccivora at 500 mg/L. [ABSTRACT FROM AUTHOR]

Abstract: Chlortoluron chlorination is studied in the pH range of 3–10 at 25±1°C. The chlorination kinetics can be well described by a second-order kinetics model, first-order in chlorine and first-order in chlortoluron. The apparent rate constants were determined and found to be minimum at pH 6, maximum at pH 3 and medium at alkaline conditions. The rate constant of each predominant elementary reactions (i.e., the acid-catalyzed reaction of chlortoluron with HOCl, the reaction of chlortoluron with HOCl and the reaction of chlortoluron with OCl−) was calculated as 3.12 (± 0.10)×107 M−2 h−1, 3.11 (±0.39)×102 M−1 h−1 and 3.06 (±0.47)×103 M−1 h−1, respectively. The main chlortoluron chlorination by-products were identified by gas chromatography–mass spectrometry (GC–MS) with purge-and-trap pretreatment, ultra-performance liquid chromatography–electrospray ionization-MS and GC-electron capture detector. Six volatile disinfection by-products were identified including chloroform (CF), dichloroacetonitrile, 1,1-dichloropropanone, 1,1,1-trichloropropanone, dichloronitromethane and trichloronitromethane. Degradation pathways of chlortoluron chlorination were then proposed. High concentrations of CF were generated during chlortoluron chlorination, with maximum CF yield at circumneutral pH range in solution. [Copyright &y& Elsevier]

Due to the fact that Iron oxide (Fe2O3) is known to have a good effect on the photochemical reaction of catalysts, an investigation in this study into the enhancement of the degradation performance of bio-electro-Fenton microbial fuel cells (Bio-E-Fenton MFCs) was carried out using three photocatalytic cathodes. These cathodes were produced at different calcination temperatures of Fe2O3 ranging from 500 °C to 900 °C for realizing their performance as photo catalysts within the cathodic chamber of an MFC, and they were compared for their ability to degrade oily wastewater. Results show that a suitable temperature for the calcination of iron oxide would have a significantly positive effect on the performance of Bio-E-Fenton MFCs. An optimal calcination temperature of 500 °C for Fe2O3 in the electrode material of the cathode was observed to produce a maximum power density of 52.5 mW/m² and a chemical oxygen demand (COD) degradation rate of oily wastewater (catholyte) of 99.3% within one hour of operation. These novel findings will be useful for the improvement of the performance and applications of Bio-E-Fenton MFCs and their future applications in the field of wastewater treatment. [ABSTRACT FROM AUTHOR]

An unexpected domino reaction of β-keto sulfones with acetylene ketones has been developed. The domino reaction of β-keto sulfones with diynones proceeded smoothly in the presence of 30 mol% K2CO3 without other additives, and afforded the novel 3(2 H)-furanone derivatives. On replacing the diynones with terminal alkyne ketones, the reaction regioselectivity was changed and sulfonylbenzenes were obtained via benzannulation in good yields. [ABSTRACT FROM AUTHOR]

ABSTRACT A series of 2-(1-(2,4-dibenzhydrylnaphthylimino)ethyl)-6-(1-(arylimino)ethyl)pyridyliron(II) complexes ( Fe1− Fe5) was synthesized and characterized. The molecular structure of the representative Fe2 was determined by single-crystal X-ray diffraction, revealing a distorted pseudo-square-pyramidal geometry around the iron center. On activation with either methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all these iron complex precatalysts performed with high activities (up to 1.58 × 107 g (PE) mol−1 (Fe) h−1) toward ethylene polymerization, producing highly linear polyethylenes with high molecular weight and bimodal distribution, which was in accordance with high temperature 13C NMR, high Tm values ( Tm ∼130 °C) and the GPC curves of the obtained polyethylenes. Meanwhile, DFT calculation results also showed the good correlation between net charges on iron and experimental activities. Compared with previous bis(imino)pyridyliron analogues, the current iron complexes containing the benzhydrylnaphthyl groups exhibited relatively higher activities and better thermal-stability at elevated temperatures, especially at 80 °C as the industrial operating temperature, and still showed high activities toward ethylene polymerization up to 8.57 × 106 g (PE) mol−1 (Fe) h−1 in the presence of co-catalyst MMAO. In addition, these iron complex precatalysts all exhibited long lifetimes. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 988-996 [ABSTRACT FROM AUTHOR]

K x RhO 2 , as an isomorphism material to Na x CoO 2 , is theoretically predicted to have rich physical properties. In this letter, we studied the chemical depotassiation process of K 0.62 RhO 2 crystals to obtain K x RhO 2 with x varied from 0.32 to 0.62. And an end-product K 0.32 RhO 2 with single phase determined through XRD refinement belongs to space group P6 3 /mmc (No. 194). Electrical transport, magneto-resistant transport and Hall measurements substantiate that K 0.32 RhO 2 is a multi-band normal metal, which can be well described by Landau Fermi liquid theory. Our finding sheds more light on the preparation and transport properties of layered oxides. [ABSTRACT FROM AUTHOR]

The intramolecular cyclization of allylamines and ketones was achieved in the presence of potassium tert-butoxide and N,N-dimethylformamide. A series of 4-arylquinolines was prepared in good yields. The reaction could be accomplished at room temperature using only a substoichiometric amount of potassium tert-butoxide. On the other hand, the reaction of the structurally analogous allyl ethers afforded diverse products. The reaction may proceed via the rearrangement of α-aminoallyl radicals and the generation of nucleophilic enamine intermediates. This finding represents a new strategy for the synthesis of quinoline derivatives from readily available 2-(allylamino)phenyl ketones. [ABSTRACT FROM AUTHOR]

The first example of phototunable SMMs has been reported. Upon UV irradiation, variations of the coordination sphere around Dy(iii) ions actually affect the magnetic behaviour of the compound via [2+2] cycloaddition reaction, leading to a magnetic transformation from the SMM behaviour to a field-induced slow relaxation. [ABSTRACT FROM AUTHOR]

A huge number of indolylglycine derivatives (III) bearing a tetrasubstituted carbon center is efficiently synthesized camphorsulfonic acid catalyzed. Friedel--Crafts reaction of indoles (II) to ketimino esters (I). [ABSTRACT FROM AUTHOR]

Abstract: Under solvothermal conditions, complexes Ni(HL2) (1) and Ni(L3)·MeOH (2·MeOH) (H3L2=N-(2-(2-hydroxybenzylideneamino)-1-(2-hydroxyphenyl)-2-(pyridin-2-yl)ethyl)picolinamide; H2L3=1-(pyridin-2-yl)prop-1-ene-1,2-diyl)bis(azan-1-yl-1-ylidene)bis((methan-1-yl-1-ylidene)diphenol) have been synthesized from the reaction of Ni(CH3COO)2·4H2O with 2-((pyridin-2-ylmethyleneamino)methyl)phenol (HL1) at 70 and 90°C, respectively. The complexes were characterized by X-ray single crystal diffraction, IR spectroscopy, and elemental analysis. The plausible mechanisms for the formation of H3L2 and H2L3 via solvothermal in situ metal–ligand reactions were proposed. [Copyright &y& Elsevier]

Abstract: ZnO nanowires were grown in situ on Zn comb-shaped interdigitating electrodes by using a simple hydrothermal reaction of metallic Zn with Na2C2O4 in solution at 140°C. ZnO nanowires were bridged across the trenched electrodes. In this process, the “pick and place” method of nanowire integration was avoided. The self-assembly grown ZnO nanowires had excellent performance as a sensor to ultraviolet (UV) light, NH3 and N(C2H5)3. The V output value was about 0.6V in air, under UV illumination, however, it increased to 1.3V. The sensitivities at 260°C were 1.3 and 1.4 when the concentrations of NH3 and N(C2H5)3 gas were 0.5 and 0.9ppm, respectively. The performance of this kind of sensors could be further improved by increasing the quantity of the Zn electrodes. [Copyright &y& Elsevier]

Abstract: Monodisperse flowerlike nanoarchitectures assembled from CdS nanoflakes with a diameter of about 0.85μm were synthesized by a hydrothermal reaction of CdCl2 with thiocarbamide, polyvinylpyrrolidone and H2O at 180°C for 6.0h. The constituent CdS nanoflakes have perfect hexagonal shape with the side lengths of 0.37–0.38μm and the thicknesses of 60–70nm. Sphere like particles assembled from CdS nanocrystals formed firstly evolved into flowerlike architectures assembled from nanoflakes via an oriented attachment process due to the selective adsorption of PVP on (001) surface of CdS with the wurtzite structure. The as-obtained CdS flowerlike nanoarchitectures with exposed {001} facets show higher intrinsic photocatalytic activity than CdS branched nanostructures and commercial powders for degradation of malachite green. [Copyright &y& Elsevier]

Abstract: Uniform spherical flowerlike SnO2 architectures with the diameters of 1.7–2.0μm were synthesized by a hydrothermal reaction of SnCl4 with NaOH and H2O in the presence of polyvinylpyrrolidone (PVP). These flowerlike architectures are assembled from submicron rods with the diameters of 300–600nm. The constituent submicron rods are single crystalline SnO2 with the tetragonal structure, and grow along the direction perpendicular to (101) facet. The spherical flowerlike architectures constructed with SnO2 submicron rods are formed via the oriented attachment process. The response performance of the sensors based on the SnO2 spherical flowerlike architectures toward ethanol and triethylamine is better than that of SnO2 powders and can be further enhanced by improving their crystallinity. The sensor response is 3.65 and 2.97 when the concentration of ethanol and triethylamine is 105 and 45ppm, respectively. [Copyright &y& Elsevier]

Abstract: TiO2 nanoflakes assembled flowerlike nanoarchitectures with diameters of 1.70–2.20μm were synthesized by a solvothermal reaction of butyl titanate with isopropyl alcohol, HF and H2O at 180°C for 12h. The constituent nanoflakes have perfect rectangular shapes with the typical widths of 0.81–0.95μm, lengths of 1.04–1.20μm and thicknesses of 0.10–0.12μm. The constituent nanoflakes are formed due to the selective adsorption of isopropyl alcohol on (010) surface of anatase TiO2. These anatase TiO2 nanoflakes assemble into flowerlike structures driven by the electrostatic attraction. The as-prepared TiO2 flowerlike nanoarchitectures exhibit enhanced photocatalytic ability to degrade methyl orange dye in comparison with commercial TiO2 powders. The photodegradation of methyl orange dye catalyzed by the anatase TiO2 nanoflake assembled flowerlike nanostructures fits a pseudo first-order reaction. [Copyright &y& Elsevier]

A series of benzimidazole-based salts, obtained through the reaction of 1-benzyl-2-phenyl-1H-benzimidazole and inorganic acid, crystallize in the chiral P1 space group, which exhibit moderate second harmonic generation (SHG) responses and ferroelectric properties. [ABSTRACT FROM AUTHOR]

Abstract: NiO crystallites based nanowires with different aspect ratios have been synthesized by a hydrothermal reaction of NiCl2 with NaC2O4 and H2O in the presence of ethylene glycol (EG) and subsequent annealing at 400°C in air. Control over the aspect ratios of NiC2O4·2H2O precursor nanowires in the range of 11–1050 was achieved by adjusting the hydrothermal reaction temperature and time. The formation of the NiC2O4·2H2O nanowires results from the selective adsorption of EG molecules on , , (010) and prismatic faces of NiC2O4·2H2O with a monoclinic structure. The gas-sensing performance of the as-prepared NiO nanowires with different aspect ratios was investigated towards toluene, ethanol, acetone, triethylamine and methanol. It was found that the gas-sensing performance was improved with an increase on the aspect ratios of NiO nanowires. [Copyright &y& Elsevier]

Abstract: Two new zinc(II)–triazole–aliphatic dicarboxylate coordination polymers, [Zn(trz)(Hsuc)] n (1), [Zn2(trz)2(tar)] n (2), have been hydrothermally synthesized by reaction of Zn salt, Htrz with H2suc and H2tar, respectively (Htrz=1,2,4-triazole, H2suc=succinic acid, H2tar=tartaric acid). Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by X-ray powder diffraction, elemental analyses, IR spectra and TG analyses. Compound 1 displays a 2D layer structure containing {[Zn4(trz)4]4+} n layers decorated by the suc ligand. Compound 2 is in a 3D structure formed by the interconnection of 2D {[Zn4(trz)4]4+} n layers with tar ligand, resulting a 3,4-connected topological network. Due to the different coordination mode and conformation of aliphatic carboxylate ligand, the similar 2D {[Zn4(trz)4]4+} n layers stack in the –AAA– fashion in 1, while the {[Zn4(trz)4]4+} n layers hold together in the –ABAB– stacking sequence in 2. Additionally, the two compounds show strong fluorescence in the solid state at room temperature. [Copyright &y& Elsevier]

The ethyl acetate fractions of aqueous extracts from two submerged macrophytes Potamogeton malaianus and Potamogeton maackianus were analyzed by gas chromatograph-mass spectrometry (GC-MS). The allelopathic activities and joint effects of the main components in ethyl acetate fractions on Microcystis aeruginosa were also determined. The results indicated that primary compositions in the ethyl acetate fractions were fatty acids, phenolic acids and hydroxy fatty acids that possessed antialgal activities. The joint effect assay for palmitic acid, benzoic acid and lactic acid showed that the additional effects were observed in the mixed organic acid, namely, the inhibitory effects of mixture groups were stronger than that of each compound alone on the growth of M. aeruginosa. [ABSTRACT FROM AUTHOR]

Abstract: The chemical oxidation of the herbicide ametryn was investigated by aqueous chlorination between pH 4 and 10 at a temperature of 25°C. Ametryn was found to react very rapidly with aqueous chlorine. The reaction kinetics can be well described by a second-order kinetic model. The apparent second-order rate constants are greater than 5×102 M−1 s−1 under acidic and neutral conditions. The reaction proceeds much more slowly under alkaline conditions. The predominant reactions were found to be the reactions of HOCl with neutral ametryn and the charged ametryn, with rate constants equal to 7.22×102 and 1.58×103 M−1 s−1, respectively. The ametryn degradation rate increases with addition of bromide and decreases with addition of ammonia during the chlorination process. Based on elementary chemical reactions, a kinetic model of ametryn degradation by chlorination in the presence of bromide or ammonia ion was also developed. By employing this model, we estimate that the rate constants for the reactions of HOBr with neutral ametryn and charged ametryn were 9.07×103 and 3.54×106 M−1 s−1, respectively. These values are 10- to 103-fold higher than those of HOCl, suggesting that the presence of bromine species during chlorination could significantly accelerate ametryn degradation. [Copyright &y& Elsevier]

Abstract: ZnO nanowires with variable aspect ratios and microstructures have been prepared by a hydrothermal reaction of Zn foil and Na2C2O4 solution at 140°C. The ZnO nanowires are single crystalline with the wurtzite structure and grow in the [0001] direction, and their aspect ratios and microstructures can be changed by tuning the reaction time and the Na2C2O4 concentration. UV and blue-green emissions that depended on the Na2C2O4 concentration are observed from the ZnO nanowires with different aspect ratios. The photosensitivity of ZnO ultralong nanowires with honeycomb-like micropatterns is found to be about 10 at 5V. [Copyright &y& Elsevier]

Abstract: Density functional theory calculations have been carried out to investigate the adsorption of reaction intermediates appearing during water–gas-shift reaction at the sulfur covered MoS2 (100) surfaces, Mo-termination with 37.5% S coverage and S-termination with 50% S coverage using periodic slabs. The pathway for water–gas-shift reaction on both terminations has been carefully studied where the most favorable reaction path precedes the redox mechanism, namely the reaction takes place as follows: CO+H2O→CO+OH+H→CO+O+2H→CO2 +H2. The most likely reaction candidates for the formate species HCOO formation is the surface CO2 reaction with H as a side reaction of CO2 desorption on S-termination with 50% S coverage. The formed HCOO species will react further with adsorbed hydrogen yielding H2COO followed by breaking its C–O bond to form the surface CH2O and O species. [Copyright &y& Elsevier]

O 2 concentration near Pt surface during oxygen reduction reaction (ORR) in 0.1 M HClO 4 has been monitored by rotating ring-disk electrodes system. At 0.8 V < E < 1.0 V (vs. RHE), O 2 concentration near Pt surface increases with potential accompanying with the decrease of ORR current at the disk electrode; O 2 concentration in the negative-going scan is larger than that at the same potential in the positive-going scan, while ORR current shows the opposite trend at ω > 400 rpm. At E > 0.8 V accumulation of O ad |OH ad at Pt disk electrode with ORR time is evident, revealing that O ad |OH ad formation rate is faster than that for the removal of OH ad to H 2 O under such conditions. At relatively lower rotation speed and faster scan rate, the cathodic current during ORR in the negative-going scan can be larger than that in the positive-going scan with a current peak at ca. 0.8 V, which is attributed to the superimposition of ORR current increase due to change of O 2 concentration near the surface and the additional reduction of O ad |OH ad formed from decomposed O 2 at higher potentials. [ABSTRACT FROM AUTHOR]

Abstract: Tetra-ether substituted imidazolium salts, LHX (where LH= N,N′-bis(2,2-diethoxyethyl)imidazolium cation and X=Br, BF4, PF6, BPh4, NO3 and NTf2 anions) were derived from imidazole. Attempts to produce aldehyde functionalized imidazolium salt through acid hydrolysis of LHBr resulted an unexpected tetra-hydroxy compound LAHBr and the dialdehyde compound LBHBr. Reaction of LHBr with Ag2O afforded [L2Ag][AgBr2] (1). Mononuclear Pd-complex trans-[L2PdCl2] (2) and dinuclear Pd-complex [(LPdCl2)2] (3) were obtained by 1:1 and 1:2 reaction of in situ generated Ag-carbene with Pd(CH3CN)2Cl2. cis-[LPdPPh3Cl2] (4) was synthesized from reaction of PPh3 with dinuclear complex 3. Hydrolysis of 3 under acidic conditions also generates a hydroxy derivative 3A and the aldehyde derivative 3B. Direct heating of LHBr with Ni(OAc)2 ·4H2O at 120°C under vacuum generated trans-[L2NiBr2] (5). These complexes were characterized by NMR, mass, elemental analysis, and X-ray single crystal diffraction analysis. Pd--Pd interaction was observed in 3. All the Pd complexes exhibited excellent catalytic activity in Heck reaction. [Copyright &y& Elsevier]

Abstract: Adsorption of hydrogen sulphide (H2S) onto activated carbons derived from oil palm shell, an abundant solid waste from palm oil processing mills, by thermal or chemical activation method was investigated in this paper. Dynamic adsorption in a fixed bed configuration showed that the palm-shell activated carbons prepared by chemical activation (KOH or H2SO4 impregnation) performed better than the palm-shell activated carbon by thermal activation and a coconut-shell-based commercial activated carbon. Static equilibrium adsorption studies confirmed this experimental result. An intra-particle Knudsen diffusion model based on a Freundlich isotherm was developed for predicting the amount of H2S adsorbed. Desorption tests at the same temperature as adsorption (298K) and at an elevated temperature (473K) were carried out to confirm the occurrence of chemisorption and oxidation of H2S on the activated carbon. Surface chemistries of the palm-shell activated carbons were characterized by Fourier transform infrared spectroscopy and Boehm titration. It was found that uptaking H2S onto the palm-shell activated carbons was due to different mechanisms, e.g. physisorption, chemisorption and/or H2S oxidation, depending on the activation agent and activation method. [Copyright &y& Elsevier]

Mechanochemical metathesis reactions were utilized to synthesize nanocrystalline ZrSi2 ranging from 9–30 nm in size. Size was controlled through dilution with CaCl2. A linear relationship was found between diluent concentration and crystallite size. Unlike typical self-propagating metathesis reactions, this reaction did not self-propagate, requiring the input of mechanical energy. [ABSTRACT FROM AUTHOR]

The title compound, C18H15BrN2O4, was synthesized by the reaction of methyl (2-hydroxy­phen­yl)acetate and 3-(4-bromo)phenyl-5-chloro­methyl-1,2,4-oxadiazole. Weak intra­molecular C—H⋯N hydrogen bonds are observed in the crystal structure. [ABSTRACT FROM AUTHOR]