N-Trifluoromethylselenophthalimide, an Electrophilic Trifluoromethylselenolation Reagent and Its Application for the Synthesis of 4-Trifluoromethylselenolated Isoxazoles.

A new electrophilic trifluoromethylselenolation reagent, N-trifluoromethylselenophthalimide (Phth-SeCF3), was developed. A strategy for the synthesis of 4-trifluoromethylselenolated isoxazoles through electrophilic trifluoromethylselenolation cyclization has been established by using Phth-SeCF3 as an electrophilic reagent. Moreover, this protocol has the features of broad substrate scope, good functional group tolerance, and high yields.

Synthesis of Spiro[5.5]trienones- and Spiro[4.5]trienones-Fused Selenocyanates via Electrophilic Selenocyanogen Cyclization and Dearomative Spirocyclization.

A practical strategy for the synthesis of spiro[5.5]trienones-fused selenocyanates and spiro[4.5]trienones-fused selenocyanates through electrophilic selenocyanogen cyclization and dearomative spirocyclization is reported. This approach was conducted under mild conditions with broad substrate scope and good functional group tolerance. The utility of this procedure is exhibited in the late-stage functionalization of nature product and drug molecules.

One-step fabrication of Cu-based metal organic framework multilayer core-shell microspheres for efficiently catalyzing the oxygen reduction reaction.

Micro/nanomaterials with multilayer core-shell structures are receiving widespread attention due to their potential in energy storage and conversion systems. However, simple fabrication of multilayered core-shell structured micro/nanomaterials with a consistent composition still faces a great challenge. Herein, a simple one-step solvothermal method is used to fabricate Cu-based metal organic framework multilayer core-shell microspheres (Cu-MOF-MCSMSs) as efficient oxygen reduction reaction (ORR) catalysts. The systematic structural evolution of Cu-MOF-MCSMSs is from microspheres to core-shell microspheres and then to multilayer core-shell microspheres. Additionally, different transition metal cations and anions can also influence the structures, compositions and thus ORR activities of the synthesized MOFs. The representative Cu-MOF-MCSMSs exhibit high ORR activity and cycling stability. The simple method can provide a good guide to fabricate other micro/nanomaterials with multilayer core-shell structures and desirable properties.

Facile construction of S-containing Co-based metal organic framework core-shell microspheres as an efficient bifunctional oxygen electrocatalyst.

A cost-effective non-noble metal bifunctional electrocatalyst towards the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) is very important for energy-related applications. Micro/nanomaterials with core-shell structures have emerged as potential non-noble metal catalyst candidates. Herein, an efficient bifunctional oxygen electrocatalyst, S-containing Co-based metal organic framework core-shell microspheres (Co-MOF-CSMSs), has been designed and constructed by using 2,2':5',2''-terthiophene-5,5''-dicarboxylic acid as a novel ligand through a facile one-step hydrothermal method. Due to the integrated favorable structural characteristics of the core-shell structure and MOFs for electrocatalysis, Co-MOF-CSMSs are revealed as a good bifunctional electrocatalyst for the ORR and OER, including an onset potential of 0.93 V vs. RHE (reversible hydrogen electrode), a half-wave potential of 0.78 V vs. RHE and an overpotential of 0.35 V at 10 mA cm-2. This work provides a low-cost and facile method to design and construct advanced micro/nanomaterials with core-shell structures to targetedly develop high-performance bifunctional oxygen electrocatalysts.

Determination of Ferulic Acid in Angelica sinensis by Temperature-Controlled Hydrophobic Ionic Liquids-Based Ultrasound/Heating-Assisted Extraction Coupled with High Performance Liquid Chromatography.

Hydrophilic ionic liquids are often used to extract the active ingredients of medicinal plants, while hydrophobic ionic liquids are rarely used to directly extract solid samples. In this paper, a simple, novel and efficient temperature-controlled hydrophobic ionic liquids-based ultrasound/heating-assisted extraction (TC-ILs-UHAE) procedure coupled with high-performance liquid chromatography (HPLC) was developed and applied to the determination of ferulic acid (FA) in Chinese herbal medicine Angelica sinensis. During the extraction procedure, hydrophobic ionic liquids (ILs) were dispersed into water to form cloudy solution (fine droplets) with the aid of ultrasound and heating simultaneous. After extraction, phase separation was easily achieved by centrifuging at 0 °C. Among all ILs used, 1-butyl-3-methylimidazolium bis(trifluoromethanesulphonyl)imide ([C4mim]NTf2) exhibited the highest extraction ability and the possible extraction mechanism was discussed. Additionally, the synergistic effect of heating and ultrasound on the extraction efficiency was investigated. Under the optimized conditions, a good linearity was observed with correlation coefficient (r) of 0.9995. The limit of detection of FA (LOD, S/N = 3) was 9.6 µg/L and the spiked recoveries of FA for real samples were in the range of 91.67 to 102.00% with relative standard deviation (RSD) lower than 3.87%. Compared with the traditional extraction methods, the proposed method gave the highest yield of FA and had the shortest extraction time. Therefore, this method is a potential simple, green and highly efficient technique and expected to be applied to the extraction of other bioactive ingredients in medicinal plants.

Pristine S,N-containing Mn-based metal organic framework nanorods enable efficient oxygen reduction electrocatalysis.

Owing to their unique physicochemical properties, metal-organic frameworks (MOFs) are a kind of promising material for electrocatalysis. However, many reports focus on the use of MOFs as precursors to produce efficient electrocatalysts by pyrolysis. The use of pristine MOFs with well-defined structures as efficient electrocatalysts directly is still a challenging problem. Herein, S,N-containing MnII[(Tdc)(4,4'-Bpy)]n with different morphologies have been obtained by using MnII, thiophene-2,5-dicarboxylate (Tdc) and 4,4'-bipyridine (4,4'-Bpy) as raw materials via hydrothermal synthesis. Furthermore, the influences of different hydrothermal reaction times (0, 2 and 4 h) and anions (SO42-, Cl-, NO3- and CH3COO-) on the morphologies, compositions and ORR activity of the resultant Mn-MOFs are also investigated at length. The results indicate that only the reaction of MnSO4 with Tdc and 4,4'-Bpy for 4 h can form relatively uniform one-dimensional (1D) MOF nanorods. The 1D nanorods combine the favorable features towards the oxygen reduction reaction (ORR), such as a high surface area and efficient 1D electron/mass transport capability. Therefore, the MnII[(Tdc)(4,4'-Bpy)]n nanorods display the highest ORR activity with an onset potential of 0.98 V and a half-wave potential of 0.78 V vs. RHE (reversible hydrogen electrode), which is even comparable to that of Pt/C. In addition, the MnII[(Tdc)(4,4'-Bpy)]n nanorods exhibit higher stability, methanol resistance and ORR selectivity than Pt/C. The present study illustrates an efficient fabrication strategy for highly efficient 1D MOF nanorods for energy storage and conversion applications.

Improved power generation using nitrogen-doped 3D graphite foam anodes in microbial fuel cells.

The properties of the anode material and structure are critical to the microbial growth and interfacial electron transfer between the biofilm and the anode. In this paper, we prepared the nitrogen-doped 3D expanded graphite foam (NEGF) by simple, rapid and inexpensive methods of liquid nitrogen expansion and hydrothermal treatment from commercial graphite foil (GF). X-ray photoelectron spectroscopy confirmed the success of nitrogen doping on expanded graphite foam (EGF). Using cyclic voltammetry and electrochemical impedance spectroscopy, the NEGF and EGF electrode exhibited increased electrochemical active surface area and fast interfacial electron transfer ability than that of pristine GF, and NEGF electrode performed even better. Scanning electron microscopy revealed that NEGF and EGF possessed graphene-like structure and large surface area. MFCs equipped with NEGF or EGF anodes, respectively, achieved maximum power density of 0.739 and 0.536 W m-2, which was about 17.4 and 12.6 times larger than that of MFCs with GF anodes (0.0451 W m-2). The anode and cathode polarization curves further confirmed that the different anode other than the cathode was responsible for the advanced performance of MFCs. The morphology of the biofilm on three kinds of anodes proved the densest biofilm formed on NEGF anode. All the results indicated the synergistic effect of 3D graphene-like structure and N-doped surface on the performance of MFCs, which might provide special insights into designing simple and efficient route for anode construction to achieve promising electricity generation.

Using 2-mercaptobenzothiazole as a nitrogen and sulfur precursor to synthesize highly active Co-N-S/C electrocatalysts for oxygen reduction.

Novel Co-N-S/C catalysts supported on carbon were obtained using a two-step procedure. The procedure consisted of the synthesis of a carbon-supported Co-2-mercaptobenzothiazole (denoted as Co-MBT/C) complex using a solvent-milling method and the pyrolysis of the Co-MBT/C complex. 2-Mercaptobenzothiazole (MBT) was used as the nitrogen and sulfur ligand for Co-MBT complex formation. X-ray diffraction (XRD), TEM, EDS and elemental mappings were used to characterize the structure changes in these catalysts before and after the heat-treatment. Several catalysts were synthesized by varying the amount of cobalt salt and pyrolysis temperature. The results showed that the optimal cobalt salt content and pyrolysis temperature were around 25 wt% and 800°C. Under the optimal conditions, an onset potential of 0.20 V and a half-wave potential of 0.05 V were reached in an alkaline electrolyte, and the Co-N-S/C catalyst possessed high catalytic activity and catalytic stability towards an oxygen reduction reaction (ORR). These results indicated that Co-N-S/C is a promising catalyst for the ORR.