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A new copper/silver-co-mediated three-component bicyclization of benzene-linked 1,6-enynes with ICF2CO2Et with TMSN3 was reported, and used to produce a wide range of hitherto unreported difluorinated tetrahydroindeno[1,2-c]azepine-3,6-diones with moderate to good yields. The mechanistic pathway consists of radical-induced 1,6-addition–cyclization, oxidative addition, reductive elimination, nitrene insertion and N–O cleavage, resulting in continuous multiple bond-forming events including C–C and C–N bonds to build up a 6/5/7 tricyclic framework. [ABSTRACT FROM AUTHOR]

A novel 3D Eu(III) metal–organic framework (Eu-MOF-1) formulated as [Eu(L)(H2O)(DMA)] (L = 2-(2-nitro-4-carboxylphenyl)terephthalic acid) has been successfully synthesized under solvothermal conditions and characterized by structural analyses. Eu-MOF-1 displays a new 3D framework containing EuIII ions, ligand L, and coordinated DMA molecules and water molecules. The fluorescence investigations indicate that Eu-MOF-1 emits bright red luminescence, and shows relatively high water stability and outstanding chemical stability under a relatively wide range of pH conditions. It is noteworthy that Eu-MOF-1 can quantitatively detect p-aminophenol (PAP) which is a metabolite of phenylamine in human urine. More significantly, Eu-MOF-1 is the first reported multi-responsive luminescent sensor for detecting the biomarker PAP, and MnVII and CrVI anions with high selectivity, sensitivity, recyclability and relatively low detection limits in aqueous solutions. Furthermore, the possible sensing mechanisms of Eu-MOF-1 for selective sensing have also been explored in detail. Eu-MOF-1 could be an ideal candidate as a multi-responsive luminescent sensor in biological and environmental areas. [ABSTRACT FROM AUTHOR]

A novel Fe-doped urchin-like Ni 2 P/Ni 3 S 2 (NPZFNS@C/NF) heterostructure with abundant hetero-interfaces and carbon-coating is successfully constructed, which exhibits outstanding oxygen evolution reaction (OER) performance and excellent hydrogen evolution reaction (HER) performance. Furthermore, it also exhibits a small overpotential of 1.5 V for overall water splitting with NPZFNS/NF as both anode and cathode, lower than most of non-noble metal-based bifunctional electrocatalysts reported. [Display omitted] • Fe-doped Fe-Ni 3 S 2 /Ni 2 P@C/NF hetero-interface electrocatalyst is firstly constructed. • The catalyst shows oustanding OER and excellent HER performances. • It can act as a bifunctional catalyst toward excellent overall water splitting bebavior. • The unique electronic structure of the catalyst is the intrinsic reason for the excellent OER and HER performances. • DFT calculations further reveal the changes the d-band center and the rate-degerming step. Interfacial engineering is an efficient strategy to develop electrocatalysts with excellent performance. By using this strategy, a novel Fe-doped urchin-like Ni 2 P/Ni 3 S 2 (NPZFNS@C/NF) heterostructure with metal–organic frameworks (MOFs) as the precursor in-suit grows on nickel foam (NF) with abundant hetero-interfaces and carbon-coating is successfully constructed. Owing to the existence of hetero-interfaces and carbon coating, the unique surface electronic structure and d-band center of NPZFNS@C/NF are also obtained. Benefiting from the regulation of electronic structure and d-band center, the NPZFNS@C/NF electrode exhibits extremely high activity for oxygen evolution reaction (OER) and high activity for hydrogen evolution reaction (HER), which shows a very low overpotential of 141 mV at the current density of 10 mA cm−2 for OER and 129 mV for HER respectively in alkaline electrolyte. Furthermore, it also exhibits a small overpotential of 1.5 V for overall water splitting with NPZFNS@C/NF as both anode and cathode, which is lower than most of non-noble metal-based bifunctional electrocatalysts reported. Density functional theory (DFT) results further confirm that the hetero-interface with carbon coating can further optimize Gibbs free energies for both OER and HER processes. This design and constructure strategy provides a new avenue for overall water splitting. [ABSTRACT FROM AUTHOR]

The direct acetoxylation of substituted benzylamines has been accomplished through methoxyiminoacyl (MIA)‐mediated Pd‐catalyzed C−H functionalization. A diverse array of phenylalanine substrates is amenable to this protocol, providing acetoxylation benzylamine derivatives with good to high efficiency. Computational results revealed that HOAc enhanced the stability of Pd−O bond, which obviously accelerate the reductive elimination step of the acetoxylation process. [ABSTRACT FROM AUTHOR]

A series of FeNi 2 S 4 /NiS hetero-interface electrocatalysts with unique electronic structures are successfully constructed by interfacial engineering. Particularly, the optimized FeNi 2 S 4 (311)/NiS (101) electrocatalyst is obtained by modulating the different exposed crystal planes, which shows superior nitrogen reduction performance with high NH 3 yield and high Faradaic efficiency. • MOF-based sulfides FeNi 2 S 4 /NiS hetero-interface electrocatalysts are firstly constructed. • FeNi 2 S 4 (311)/NiS(101) shows superior electrocatalytic NRR performance. • The unique surface electronic structure of catalysts is the intrinsic reason for the excellent NRR performance. • DFT calculations further reveal the changes the d-band center and the rate-degerming step. Electrocatalytic Nitrogen Reduction Reaction (ECNRR) is a promising alternative NH 3 production method relative to Haber-Bosch process. However, the ECNRR still suffers from rather low NH 3 yield and selectivity (Faradaic efficiency (FE)) due to the poor catalytic activity of catalysts. Herein, benefiting from interface engineering, FeNi 2 S 4 /NiS hetero-interface electrocatalysts with unique electronic structures are successfully constructed, which the optimized catalyst can enhance the adsorption of N 2 molecules meanwhile inhibit H atoms adsorption. Significantly, the NH 3 yield and FE of FNS/CC-2 are reached to 128.398±1.32 μg h−1 cm−2 and 28.64 ± 0.18% which are higher than most of non-noble metal-based NRR electrocatalysts in alkaline electrolyte reported. Detailed experimental investigation and DFT calculations reveal that the enhanced electrocatalytic performance and selectivity of FeNi 2 S 4 /NiS towards N 2 are attributed to the changes of the D-band center and electronic structure of electrocatalyst surface. The construction strategy of this NRR electrocatalyst provides a new avenue on electrocatalytic research. [ABSTRACT FROM AUTHOR]

The study investigates the practical application of cyclic wet/dry corrosion tests in simulated industrial atmospheres to assess the impact of chromium (Cr) on the protective properties of vanadium micro‐alloyed weathering steels. Two types of steels were examined: a V‐N steel and a V‐N‐Cr micro‐alloyed weathering steel. These steels were subjected to corrosion tests with 0.01 mol/L NaHSO3 at a pH range of 4.4–4.8 for varying durations. The findings indicate that the inclusion of Cr in the composition of vanadium micro‐alloyed weathering steel enhances corrosion resistance and leads to the accumulation of Cr in the inner rust layer. Furthermore, the distribution of corrosion‐resistant elements (Cr, Ni, Cu, P, and Mo) in V‐N and V‐N‐Cr steels is analyzed. The rust layer was observed to exhibit stratification in the corrosive environment, with the outer layers being dense and uniform, while the inner layers were porous and exhibited poor adhesion to the matrix. The study also delves into the anticorrosion mechanism of vanadium weathering steel using techniques such as X‐ray diffractometer, electron probe microanalysis, and potential‐phase diagram. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) have emerged as a promising electrode material for supercapacitors owing to their high porosity and a regular porous structure, however, the capacitance performance and/or ion conduction rate performance of most MOFs with poor electrical conductivity are greatly hindered. To increase the bulk electrical conductivity and the efficiency of MOFs, an effective method was proposed by interweaving organic conductive polymer polyaniline (PANI) and MOF crystals (ZIF-67) grown in situ. As a result, the highly conductive PANI that interlink the MOF particles (denoted as ZIF-67@PANI) increase the electron transfer between MOF particles while the effective porosity of the MOF is maintained, which greatly improves the electrical conductivity and capacitance of MOFs. Electrochemical studies indicates that the ZIF-67@PANI exhibits ultrahigh specific capacity of 1123.65 C g−1 at a current density of 1 A g−1 in a three-electrode system, superior rate capability (648.9 C g−1 at 10 A g−1 current density) and excellent cycling stability (92.3% capacity retention after 9000 cycles). Furthermore, a symmetrical supercapacitor device based on ZIF-67@PANI network exhibits ultrahigh energy density of 71.1 W h kg−1 at a power density of 504.72 W kg−1 at 1 A g−1 current density. The capacitance performance of ZIF-67@PANI- 2 we report here is the best among the supercapacitor materials formed by MOFs and conductive polymers up to date, confirming the importance of hybrid materials on the nanoscale and the significance of in situ synthetic chemistry. PANI-coated in-situ growth of ZIF-67 can greatly improve the conductivity of ZIF-67 and exhibit excellent capacitor performance. Image 1 • The ZIF-67@PANI hybrids are prepared and exhibit excellent capacitor behaviors. • The ZIF-67@PANI- 2 capacitor shows specific capacity of 2497 F g−1 at 1 A g−1 in a 3-electrode system. • The capacitance of the capacitor remains 92.3% at 5 A g−1 after 9000 cycles. [ABSTRACT FROM AUTHOR]

• A new metal–organic framework (Eu-MOF- 1) based on Eu(III) and carboxylate linker was synthesized. • Eu-MOF- 1 exhibits an unusual 3D framework based on 1D metal-carboxylate chains. • Eu-MOF- 1 was used as multi-responsive fluorescence sensor for the detection of biomarker 1-naphthol. • Eu-MOF- 1 as a sensor shows high selectivity, sensitivity and remarkable recyclability. A new three-dimensional Eu(III) metal–organic framework Eu(III)-MOF- 1 formulated as [Eu 3 (BDC) 4.5 (H 2 O)(DMF) 2 (H 2 BDC = 1,4-benzenedicarboxylic acid), has been successfully synthesized by solvothermal methods and characterized by structural analyses and luminescence studies. Crystallographic studies reveal that the Eu-MOF- 1 exhibits an unusual 3D framework based on 1D metal-carboxylate chains. Significantly, the luminescence explorations demonstrate that the Eu-MOF- 1 is the first multi-responsive fluorescence sensor for sensing biomarker 1-naphthol (1-N) of carbaryl exposure, Fe3+ ions and MnO 4 − ions with high sensitivity, selectivity and excellent recyclability through luminescence quenching. Moreover, the possible mechanisms of selective detection have been investigated in detail. This material could be a promising luminescent sensor for practical applications. [ABSTRACT FROM AUTHOR]

Three novel Cd(II)/Zn(II) coordination polymers (CPs), namely [Cd(L)(BPDC)0.5H2O]·0.5H2O (1), [Zn2(L)2(BPDC)]·2H2O (2) and [Cd2(L)(BTC)H2O]·3H2O (3) (L = 4-(tetrazol-5-yl)phenyl-4,2′:6′,4′′-terpyridine, H2BPDC = 4,4′-biphenyldicarboxylic acid, and H3BTC = 1,3,5-benzenetricarboxylic acid), have been successfully synthesized and characterized. CP 1 and CP 2 display new two-dimensional double-layered honeycomb frameworks containing uncoordinated nitrogen atoms from pyridine and tetrazole rings, which can easily form hydrogen bonds with various analytes. CP 3 exhibits a 3D framework also with uncoordinated nitrogen atoms from pyridine and tetrazole rings. The fluorescence explorations indicate that CPs 1–3 exhibit strong blue luminescence and excellent chemical stability under a relatively wide range of pH conditions. It is worth noting that CPs 1–3 can quantitatively detect hippuric acid (HA), which is a metabolite of toluene in human urine, with high selectivity, sensitivity, fast response and relatively low detection limits. Moreover, the sensing mechanism of CPs 1–3 for HA can mainly be ascribed to fluorescence resonance energy transfer (FRET). CPs 1–3 could be ideal candidates as HA sensors in human urine samples for practical applications. Notably, to the best of our knowledge, we report for the first time Cd(II)/Zn(II)-based luminescent sensors for detecting HA in simulated urine. [ABSTRACT FROM AUTHOR]

Carbonate weathering and the CO 2 consumption in karstic area are extensive affected by anthropogenic activities, especially sulfuric and nitric acids usage in the upper-middle reaches of Wujiang River, China. The carbonic acid would be substituted by protons from sulfuric and nitric acids which can be reduce CO 2 absorption. Therefore, The goal of this study was to highlight the impacts of sulfuric and nitric acids on carbonate dissolution and the associated deficit of CO 2 uptaking during carbonate weathering. The hydrochemistries and carbon isotopic signatures of dissolved inorganic carbon from groundwater were measured during the rainy season (July; 41 samples) and post-rainy season (October; 26 samples). Our results show that Ca 2 + and Mg 2 + were the dominant cations (55.87–98.52%), and HCO 3 – was the dominant anion (63.63–92.87%). The combined concentrations of Ca 2 + and Mg 2 + commonly exceeded the equivalent concentration of HCO 3 − , with calculated [Ca 2 + + Mg 2 + ]/[HCO 3 − ] equivalent ratios of 1.09–2.12. The mean measured groundwater δ 13 C DIC value (− 11.38‰) was higher than that expected for carbonate dissolution mediated solely by carbonic acid (− 11.5‰), and the strong positive correlation of these values with [SO 4 2 − + NO 3 − ]/HCO 3 – showed that additional SO 4 2 − and NO 3 − were required to compensate for this cation excess. Nitric and sulfuric acids are, therefore, suggested to have acted as the additional proton-promoted weathering agents of carbonate in the region, alongside carbonic acid. The mean contribution of atmospheric/pedospheric CO 2 to the total aquatic HCO 3 – decreased by 15.67% (rainy season) and 14.17% (post-rainy season) due to the contributions made by these acids. The annual mean deficit of soil CO 2 uptake by carbonate weathering across the study area was 14.92%, which suggests that previous workers may have overestimated the absorption of CO 2 by carbonate weathering in other karstic areas worldwide. [ABSTRACT FROM AUTHOR]

Oxygen evolution reaction (OER) in pH-neutral electrolyte is considered more difficult for the additional adsorption and the dissociation process of H 2 O. Herein, by in-suit construction of the heterostructure between MgO and NiCo 2 S 4 on carbon cloth (CC), a novel MgO/NiCo 2 S 4 heterostructure on CC (MgO/NCS-CC) is successfully fabricated. Benefitting from the optimized electronic structure attributed to the construction of hetero-interface, and the intense adsorption of H 2 O on the surface of catalysts owing to the introduction of hydration-effect-promoting (HEP) element Mg, the MgO/NCS-CC exhibits outstanding OER activity with overpotential of 145 mV at the current density of 10 mA·cm−2 in pH-neutral electrolyte and can maintain stability over 40 h. Density-functional theory (DFT) also demonstrates that the MgO/NiCo 2 S 4 heterostructure can effectively adjust the electronic structure and enhance the adsorption of reactant, thus further optimizing Gibbs free energies and improving the activity for OER in pH-neutral electrolyte. [Display omitted] • The hydration-enhancing-effect element Mg effectively enhanced the adsorption of H 2 O on the surface of catalyst. • The unique electronic structure of the heterostructure is the intrinsic reason for the super OER performance. • The catalyst shows outstanding OER performances and excellent stability in pH-neutral condition. • DFT calculation further reveals the change of electronic structure and the enhancement of water adsorption of the catalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] • Direct ortho -diarylation via MIA-mediated Pd-catalyzed C-H functionalization. • Di- ortho -arylated phenylalanine derivatives with good to high efficiency. • Localized orbital between Pd(IV) and Ag 2 CO 3 favored the reductive elimination step. The direct di -ortho -arylation of substituted phenylalanines has been accomplished via methoxyiminoacyl (MIA)-mediated Pd-catalyzed C H functionalization. A diverse array of phenylalanine substrates is amenable to this protocol, providing di -ortho -arylated phenylalanine derivatives with good to high efficiency. Computational results revealed that a bimetallic interaction between Pd(IV)-Ag(I) was formed through the localized orbital, which obviously favored the reductive elimination step of the arylation process. [ABSTRACT FROM AUTHOR]