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We disclose herein a Au(I)-catalyzed domino cyclization of 1,6-diynes incorporated with indole. This protocol enabled the diastereoselective buildup of indole-fused azabicyclo[3.3.1]nonanes from linear precursors. Density functional theory calculations showed that the reaction proceeded via an unprecedented cascade dearomatization/rearomatization/dearomatization process. Independent gradient model analysis revealed that a noncovalent attractive interaction between the distal alkyne and the Au/proximal complex was responsible for the chemoselectivity of the first spirocyclization step.

The 2-methoxyiminoacyl-mediated arylation of substituted phenylalanines has been examined. Selective monoarylation at the ortho position was achieved using pyridone ligands which decelerate the arylation process. Density functional theory (DFT) study of a continuous C-H arylation process that included the first and second arylation stage was performed. The computational result shows that the introduction of a pyridone ligand obviously disfavors the second arylation stage, which directly contributes to the selectivity between the mono/diarylated products. Furthermore, results of the kinetic isotope effect and a control experiment are agreed with DFT study.

Electrocatalytic NO reduction controls NO emission and produces NH3 at ambient conditions. Herein, NiO nanosheet array on titanium mesh is proposed as a high-active and selective electrocatalyst for NO reduction reduction, attaining a Faradic efficiency of up to 90% with a NH3 yield of 2130 µg h−1 cm−2. Its aqueous Zn-NO battery can generate electricity with a power density of 0.88 mW cm−2 and simultaneously offer an NH3 yield of 228 µg h−1 cm−2. The NO electroreduction mechanism on NiO is revealed using theoretical calculations.

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.

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.

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.

The detection of volatile amines has attracted great attention due to their high toxicity and widespread existence. Herein, we report a new example of a metal–organic framework (Co-MOF-1) for the discriminative detection of alkylamines. Co-MOF-1 that was assembled by Co(II), N3− and viologen-based ligand [H2L]Cl2 ([1,1′-bis(4-carboxylatobenzyl)-4,4′-bipyridinium] dichloride) is a 3D cationic pcu framework with 1D channels containing electron-deficient viologen units, exhibits typical electrochemical redox properties and photochromic properties, and is involved in the radical formation via photoinduced electron transfer from nitrate ions and carboxylate groups in the channels to viologen moieties. More importantly, Co-MOF-1 shows different color responses to different volatile amine vapors of different types and molecular sizes, which is attributed to the electron transfer from the amine to viologen. Moreover, the reason why Co-MOF-1 can detect amines distinguishably is the different sizes of the substituents of the amine molecules and the number of N–H bonds of the amine molecules. Furthermore, the portable test paper was successfully prepared and provided a convenient and discernible detection of volatile amine vapors by depositing Co-MOF-1 onto the filter paper, which can also be used as an erasable inkless printing medium.

Interfacial engineering is an efficient strategy to develop electrocatalysts with excellent performance. By using this strategy, a novel Fe-doped urchin-like Ni2P/Ni3S2 (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.

An aerobic oxidative cyanation for the synthesis of α-aminonitriles was reported. The formation of C(sp3)-CN bonds was achieved under a metal-free condition by utilizing azobis(isobutyronitrile) as a sole organic cyanide source with the combination of pivalic acid and sodium acetate as additives.

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.

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.

A new three-dimensional Eu(III) metal–organic framework Eu(III)-MOF-1 formulated as [Eu3(BDC)4.5(H2O)(DMF)2] (H2BDC = 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 MnO4− 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.

Carbon sequestration resulting from carbonate rock weathering is closely linked to the global carbon cycle and has turned out to be important in the adjustment of atmospheric CO2 levels. Traditional karst dynamic models based on water–rock–gas interactions underestimate carbon sink fluxes related to carbonate rock weathering because they ignore the utilization of dissolved inorganic carbon (DIC) by aquatic organisms. In this study, a new model based on water–rock–gas–organism interactions was applied in the Pearl River basin, China, to recalculate atmospheric CO2 consumption and to develop an accurate estimation model for carbon sink fluxes at catchment scale. Stable carbon isotope (δ13C) and C/N ratios were used in the counting processes. Data were collected from published literature as well as through field investigation and laboratory analysis. Results show that the Pearl River carbon sink in the Pearl River is 4.31 × 109 kg/a, i.e., 15.8 × 109 kg of atmospheric CO2 per year. Of this, the carbon sink resulting from carbonate rock weathering amounts to 2.14 × 109 kg/a, i.e., 49.7 % of the total. The three largest tributaries of Pearl River, Dongjiang, Beijiang, and Xijiang, respectively absorb 0.5 × 109, 1.19 × 109, and 2.62 × 109 kg of carbon from the atmosphere annually, accounting for 12, 28 and 60 % of the river’s total carbon sink. When compared with the results of previous researches that disregarded the role of aquatic organisms, the new calculation method provides a carbon sink flux value that is 1.2–3.3 times higher, and 1.6 times higher on an average. To improve the calculation accuracy of atmospheric CO2 consumption in global karstic rivers, further research is needed regarding carbon sequestration mechanisms that involve aquatic organisms.

The removal of perfluorooctanoate （PFOA） and turbidity from model solution by coagulation was investigated. A polyaluminum chloride (PACl) was used as a coagulant in the coagulation process. The effects of coagulant dose, slow mixing time, solution pH value and initial turbidity on the removal of both PFOA and turbidity from water were studied. It was found that the removal rate of PFOA in water increase along with the increase in slow mixing time, initial turbidity and PAC dose. The removal rate of PFOA is more effective at the near neutral solution pH values and the high initial turbidity. The removal percents of PFOA exceed 80% at the optimal condition. The removal mechanism was speculated to be the electrostatic interaction and hydrophobic interaction in coagulation process.