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The use of gem‐difluorinated cyclopropanes (gem‐DFCPs) as fluoroallyl surrogates under transition‐metal catalysis has drawn considerable attention recently but such reactions are restricted to producing achiral or racemic mono‐fluoroalkenes. Herein, we report the first enantioselective allylation of indoles under rhodium catalysis with gem‐DFCPs. This reaction shows exceptional branched regioselectivity towards rhodium catalysis with gem‐DFCPs, which provides an efficient route to enantioenriched fluoroallylated indoles with wide substrate scope and good functional group tolerance. [ABSTRACT FROM AUTHOR]

Agroforestry, as a phytoremediation measure, shows great potential for mitigating land degradation by constructing multidimensional and efficient agroforestry composite systems through regulating the microenvironment of agroforestry sites and improving soil properties. However, the effects of different agroforestry composite management modes on saline soils and the interactions between soil–plant systems under salt stress conditions in coastal areas remain largely unexplored. In this study, two salt‐tolerant tree species (Sapium sebiferum (Linn.) Roxb and Zelkova serrata (Thunb.) Makino) and four crop species (Medicago sativa, Sesbania cannabina, Sorghum bicolour, and Avena sativa) were selected for intercropping in eight composite patterns via field experiments, with dynamics of soil physicochemical properties and crop photosynthesis observed. The results showed that treatments intercropped with M. sativa had the highest soil bulk density range (1.41–1.48 g cm−3). The dynamics of topsoil (0–10 cm) chemical properties showed similar change patterns among treatments, whereas those of the 10–40 cm soil chemical properties (especially soil pH, soil organic matter [SOM], and total nitrogen [TN]) showed heterogeneity. Moreover, planting S. sebiferum (L.) Roxb under the same crop conditions increased tree height growth rate and survival rate by 75%–114% and 14%–33%, respectively, relative to planting Z. serrata (T.) Makino. Furthermore, a significant negative correlation was observed between soil moisture with crop intercellular CO2 concentration (λ = −0.77), while significant positive correlations were found between crop net photosynthetic rate (Pn) with soil TN (λ = 0.71), as well as SOM with atmospheric CO2 content (λ = 0.72). Structural equation modeling showed significant direct effects between tree height growth rate with soil TN and SOM. Soil moisture (λ = 0.47) and tree height growth rate (λ = 0.53) were dominant drivers of crop Pn. Our findings provide useful information for the prevention of coastal saline soil degradation and sustainable development of agroforestry. [ABSTRACT FROM AUTHOR]

Here we present a modular, chemo‐, regio‐, and stereoselective synthesis of fully‐substituted and configuration‐defined alkyl vinyl ethers (AVEs) using simple chemical feedstocks. The distinctive approach involves the chemo‐ and regioselective functionalization of the CF2 unit in gem‐difluorinated cyclopropanes with O−H and C−H nucleophiles in a specific order. The resulting highly functionalized cyclopropanyl ethers then undergo a stereoselective ring‐opening process to produce fully‐substituted and configuration‐defined AVEs. These AVEs are rarely accessible through conventional methods and are easily transformable. Mechanistic experiments indicate that the success of this method relies on the use of dual‐functional copper catalysis, which is involved in both the functionalization of the CF2 unit and the subsequent ring‐opening process. [ABSTRACT FROM AUTHOR]

The overarching goal herein is to identify the factors dominating the performance of a‐IGZO‐based memristors. Despite the highest on/off ratio, greater than 104 with a preferred minimal set/reset bias achieved from a‐IGZO‐based memristors, it is observed that the switching performance and stability/reliability of the devices is significantly dominated by the VO·· density and metallization material, depending on their reactivity with IGZO. As the first governing factor, ensuring optimal VO·· concentration in the switching layer IGZO (VO··/OOx ratio 24.3% in this study) is crucial to obtain the tractable formation and rupture of conduction filament. Neither higher nor lower VO·· density than the optimized results in detrimental reliability issues, which may be ascribed to an uncontrollable filament in an abundant vacancy environment or a weak conducting path, respectively. As the second governing mechanism determining the memristor performance and reliability, it is suggested that metallization materials need to be carefully selected based on the thermodynamic redox potential and interfacial stability of the metallization material with IGZO. Metallization materials with larger reduction potential and interfacial stability are found to yield higher switching on/off ratio and greater device performance reliability. [ABSTRACT FROM AUTHOR]

The pyrolysis and catalytic reforming process of waste plastics are the best pathways to handle vast amounts of waste plastics as they can convert these waste polymers into sustainable products. This study aims to incorporate a natural‐clay‐mineral (NCM) with LaFeO3 nanoparticles, with the LaFeO3/NCM catalyst in the pyrolysis of polypropylene (PP) being used as an example of plastic waste. The decomposition of PP with and without catalyst has been theoretically studied using thermogravimetry (TG) and differential scanning calorimetry (DSC) measurements under atmospheric pressure and nitrogen atmosphere. The TG/DSC results show that (i) the required temperature for pyrolysis of PP with or without catalyst in a practical system ranges from 460°C to 480°C; (ii) the amount of coke produced on the surface of the NCM or LaFeO3 is about 2 wt.% compared with the initial plastic levels; (iii) with the catalyst, PP not only goes through the phase transitions of solid to liquid to gas but also decomposition and combination processes between components from the hydrocarbon chain scission of PP. Gas chromatography–mass spectrometry (GC–MS) results show significant differences in the fuel oil recovered from the pyrolysis and catalytic reforming process. In the presence of the catalyst, cracking components consist of 49.3% alkenes (branched‐chain alkenes, cyclo‐alkenes, and alkenes) and 34.4% alkanes, while without the catalyst, branched‐chain alkenes were up to 90.2%. Repeated pyrolysis and GC–MS investigations demonstrated the reusability of the LaFeO3/NCM catalyst, which is promising for its recycling and the efficient pyrolysis of PP. [ABSTRACT FROM AUTHOR]

Herein, we report a rhodium catalyzed directing‐group free regioselective C−H allylation of simple arenes. Readily available gem‐difluorinated cyclopropanes can be employed as highly reactive allyl surrogates via a sequence of C−C and C−F bond activation, providing allyl arene derivatives in good yields with high regioselectivity under mild conditions. The robust methodology enables facile late‐stage functionalization of complex bioactive molecules. The high efficiency of this reaction is also demonstrated by the high turnover number (TON, up to 1700) of the rhodium catalyst on gram‐scale experiments. Preliminary success on kinetic resolution of this transformation is achieved, providing a promising access to enantio‐enriched gem‐difluorinated cyclopropanes. [ABSTRACT FROM AUTHOR]

Herein, we report a rhodium catalyzed directing‐group free regioselective C−H allylation of simple arenes. Readily available gem‐difluorinated cyclopropanes can be employed as highly reactive allyl surrogates via a sequence of C−C and C−F bond activation, providing allyl arene derivatives in good yields with high regioselectivity under mild conditions. The robust methodology enables facile late‐stage functionalization of complex bioactive molecules. The high efficiency of this reaction is also demonstrated by the high turnover number (TON, up to 1700) of the rhodium catalyst on gram‐scale experiments. Preliminary success on kinetic resolution of this transformation is achieved, providing a promising access to enantio‐enriched gem‐difluorinated cyclopropanes. [ABSTRACT FROM AUTHOR]

Abstract: Iron‐immobilized nanoporous carbon is a well‐known adsorbent used in treating arsenic‐contaminated waters. In this contribution, we present findings on the adsorptive interactions and dynamics of arsenate–goethite cluster ([FeO(OH)]6) with carbon nanotubes (CNTs) using hybridized quantum mechanics/molecular mechanics (QMMM) calculations. The CNTs adsorption mechanism is of interest since a better understanding of the fundamental interactions between arsenate, goethite, and carbon surfaces would translate to advances in CNT‐based adsorbent production and utilization. Novel applications of general amber force field (GAFF) and isobaric‐isothermal Gibbs ensemble Monte Carlo (NpT‐GEMC) methods are described. By the abovementioned methods, we postulate that the [FeO(OH)]6/CNT‐2.3 (diameter 2.3 nm ‐ mesoporous) system enhances the qualitative (i.e., improved chemisorption) rather than the quantitative adsorptive aspect (i.e., total HAsO 4 2 − ions adsorbed) in comparison to the [FeO(OH)]6/CNT‐1.6 (diameter 1.6 nm ‐ microporous) system. [ABSTRACT FROM AUTHOR]

Thin films of Co xCu yO z have been coated on aluminum substrates via sol-gel route using low concentration of copper and cobalt precursors at annealing temperatures in range of 500-650 °C. The coatings were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-Vis-NIR spectrophotometry, and nanoindentation. The XRD analysis in 2 θ-range of 30°-42° revealed that the coatings exhibited low crystallinity of CoCu2O3, CoCuO2, and CuCoO2. The surface bonding structure analyzed using XPS indicated that the coating contained: Cu (tetrahedral Cu+ and octahedral Cu2+), Co (octahedral Co3+, tetrahedral Co2+, and mixed Co2+ and Co3+), and O (lattice, surface, and sub-surface oxygens). The optical properties characterized using UV-Vis-NIR showed that the reflectance spectra of coatings formed a spectrally solar selective absorber profile associated with the interference peaks and the absorption edges around wavelengths of below 1.2 μm. The maximum absorptance ( α = 75.8%) was shown by coating synthesized at 500 °C. The mechanical properties of coatings showed that the increase of annealing temperature increased the coating's hardness ( H) and the elastic modulus ( E) due to the enhancement of the [CoCuO2/CuCoO2]:[CoCu2O3] oxide phases ratio, as the result, an excellent stability of the wear resistance ( H/E) of around ∼0.035 was recorded. [ABSTRACT FROM AUTHOR]

Ceramic coatings of distinct microstructures, namely TiSiN and CrN, were deposited on tool steels. The corrosion resistance of the coated steels was measured. Following nanoindentation, immersion tests were conducted in 70% HNO3 solution for 96 h. Deformed CrN, where deformation occurred through shear sliding of columnar grains, was insensitive to corrosion attack. In contrast, open cracks formed in the indented TiSiN coating, serving as pathway for reactive agents to penetrate through the coatings. Finite element analysis was applied to evaluate the damage tolerance of the coatings and its impact on the corrosion resistance of the coated steels. [ABSTRACT FROM AUTHOR]

Abstract: Organoboron is well‐developed and broadly utilized organometallic reagents in organic synthesis due to its extraordinary performances in transition‐metal catalyzed C‐C and C‐X bonds construction. Catalytic C—H borylation and further transformations catalyzed by transition metal catalysts in the absence of oxidants were well studied in decades. However, as known, transition metal catalyzed oxidative C—H borylations were not reviewed up to date. In this article the oxidative borylation of C(sp2)‐H and C(sp3)‐H bonds were summarized and their mechanisms were also accounted. [ABSTRACT FROM AUTHOR]

The article presents chemical equations on article "Copper-Catalyzed Amidation of Arylboronic Acids with Nitriles." by and others, published in the "Synlett" in 2016.