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A tetrabutylammonium decatungstate (TBADT)-photocatalyzed direct coupling of inert alkanes and quinoxalin-2(1H)-ones with H2 evolution was developed at room temperature.

A general and metal-free visible-light-induced decarboxylative arylation procedure at room temperature was described for the construction of acylated heterocyclic derivatives, such as benzimidazo/indolo[2,1-a]isoquinolin-6(5H)-ones, aroylazaspiro[4.5]trienones, thioflavones, and so on. This practical arylation procedure was conducted by using 2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile (4CzIPN) as a photocatalyst under mild conditions, which avoided the use of an additional base, traditional heating, and metal reagents.

Photocatalytic strategies for the preparation of 3-phosphoryl/trifluoromethyl/thiocyanato azaspiro[4.5]trienones via a radical-initiated cascade annulation reaction of N-arylpropiolamides with phosphorus reagents, 1-trifluoromethyl-1,2-benziodoxol-3(1H)-one (Togni's reagent II) or NH4SCN have been developed under blue LED irradiation at room temperature. The novel synthetic methodologies constitute the first application of 2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile (4CzIPN) as a photocatalyst for the synthesis of spiro-γ-lactam derivatives, in which the use of transition metals and a high reaction temperature could be avoided. The reactions are operationally simple, easy to scale up, and metal-free with wide reaction scope and good functional group tolerance.

Bismuth vanadate (BiVO4) could be prepared by the hydrothermal kettle method. Herein, the synthesized BiVO4-180 is demonstrated to be a versatile and stable heterogeneous photocatalyst for a series of C(sp2)–H functionalization reactions under visible light irradiation at ambient conditions. A series of functionalized compounds such as tetrahydroquinolines, 3-arylmethyl indoles, α-aryl α-amino acid esters, and sulfurized/selenized/thiocyanated heterocycles were successfully synthesized in good yields (>70 examples, including modification of drugs and peptides). The BiVO4 photocatalyst has the advantages of being recyclable, low-cost, air-tolerant, and high efficiency, which is the typical characteristic of overcoming the shortcomings of homogeneous catalysts.

Recently, silver nanoparticles(NPs)-based photocatalysts have attracted more attention due to their enhanced visible light photocatalytic activity. In this work, a new Ag@Ag3PO4photocatalyst have been prepared by precipitation replacement and reduction methods. The products were characterized by XRD and SEM. The photocatalytic activities was evaluated using 2-naphthol and methyl orange degradations under visible light irradiation (λ > 400 nm). The degradation rates of 2-naphthol and methyl orange with initial concentration of 15 mg•L-1reached 80% and 99% respectively by using 0.6 g•L-1Ag@Ag3PO4. The photocatalytic mechanism was discussed.

The graphene/poly(vinyl alcohol) nancomposites with enhanced filler-matrix interfacial interaction were fabricated via water-blending partially reduced graphene oxide (PRGO) and poly(vinyl alcohol)(PVA). The nanocomposites were characterized by X-ray Diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), Scanning Electron Microscopy(SEM), thermogravimetry(TG). The results showed that the graphene nanosheets were homogeniously dispersed in the PVA matrix and enhanced interfacial adhesion was greatly enhanced due to new covalent linkage and hydrogen-bonding between graphene and PVA backbone. The mechanical and thermal properties of the nanocomposites were significantly improved at low graphene loadings. An 116% increase in tensile strength and a 19°C improvement of onset thermal degradation temperature were achieved by the addition of only 0.8 wt% graphene.

The molecular design for inherently flame-retardant poly(lactic acid) (IFR-PLA) was outlined and achieved by chemically incorporating an effective organophophorus-type flame retardant (FR) into the PLA backbone via the chain extension of the dihydroxyl-terminated prepolymer with 1, 6-hexamethylene diisocyanate (HDI). The structure of IFR-PLA was characterized by 1 H- and 31 P-nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy. IFR-PLA was further blended with the commercial PLA to prepare flame retardant PLA blends (PLA-FR blend). The relevant properties of IFR-PLA and PLA-FR blends were evaluated by differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), limiting oxygen index (LOI) measurements and UL-94 tests. The thermal analysis revealed that the char yield of IFR-PLA and PLA-FR blend above 400 °C was greatly enhanced compared to that of pure PLA. The LOI value was significantly improved from 19 for pure PLA to 29 when 1 wt% of phosphorus content was introduced and all IFR-PLA samples achieved V-0 rating in the UL-94 tests. PLA-FR blends had an LOI value of 25–26 and UL-94 V-2 rating at 20 wt% of IFR-PLA content. The tensile strength of all the FR PLA systems was ca. 60 MPa. The method used in this study provided a novel route to permanently flame retard PLA.

Graphene has attracted much interest in recent years due to its unique and outstanding properties. Dif- ferent routes to prepare graphene have been developed and achieved. Preparation methods of graphene used in re- cent years are intensively introduced, including micromechanical cleavage, chemical vapor deposition, liquid/gas- phase-based exfoliation of graphite, epitaxial growth on an insulator, chemical reduction of exfoliated graphene oxide, etc. And their advantages and shortcomings are further discussed in detail. The preparations of graphene are also prospected.

A novel type of molecular tweezers with different chiral center and cleft has been designed and prepared by using α-hyodeoxycholic acid as spacer and d / l -amino acid methyl ester as chiral arm attached at 3-position. Their structures were elucidated by 1 H NMR, FTIR and elemental analysis. Their recognition properties for various d / l -amino acid methyl esters were also investigated. The preliminary results indicated that these chiral single-armed molecular tweezers exhibited good recognition ability for d / l -amino acid methyl esters with high association constant (up to 5.24 × 10 3 L mol −1 ).

Dispersion copolymerization of methyl methacrylate (MMA) and acrylic acid (AA) was carried out in an ethanol/water media with 2,2′-azobisisobutyronitrile (AIBN) as the initiator and poly (N-vinylpyrrolidone) as the stabilizer in the presence of ethylene glycol dimethylacrylate (EGDMA) as the crosslinking reagent. The kinetic characteristics of the dispersion copolymerization of MMA and AA were investigated. It was proposed that there were two nucleation mechanisms in the dispersion copolymerization of MMA and AA: homogeneous nucleation and heterogeneous nucleation. Furthermore, the effects of reaction parameters such as monomer compositions, AIBN concentrations, or reaction temperatures on the polymerization rates of the mini-emulsion-nucleated dispersion copolymerization and the partitioning of carboxyl group in the particles and media were also studied.

Micron-size functional crosslinked poly(methyl methacrylate) (PMMA) particles with narrow size distribution in the range of 1∼5 µm were prepared by dispersion copolymerization in polar media with poly(N-vinylpyrrolidone)(PVP) as steric stabilizer, 2,2′-azobisisobutyronitrile(AIBN) as initiator and ethylene glycol dimethylacrylate (EGDMA) as crosslinking agent. The effects of functional comonomer acrylic acid (AA) concentration, contents in AIBN, EGDMA and PVP, media polarity as well as reaction temperature on the particle size and size distribution were investigated. Particle size initially increased, and then decreased with increasing AA concentration in the range of 0.7∼3.5 mol l−1, having a maximum of 5.01 µm at the concentration of 2.1 mol l−1, while size distribution became broader. This was regarded as the result of different roles of PAA in the process. Particle size increased with decreasing media polarity and stabilizer concentration, and with increasing initiator concentration and reaction temperature. The resulting particle shapes were observed by transmission electron microscopy and the presence of carboxyl groups on the surface of the particles was confirmed by Fourier-transform infrared spectroscopy. Copyright © 2003 Society of Chemical Industry

Polystyrene beads bearing chiral 1,1′-bi-(2-naphthol) (BINOL) moieties are readily prepared by Suzuki couplings between chiral 6-bromo-1,1′-bi-(2-naphthol)s and crosslinked polystyrene beads containing phenylboronic acid residues. With this method, no protecting groups for the phenolic residues are required; any boronic acid groups that do not take part in the Suzuki coupling are removed from the support by in situ hydrolysis, and the BINOL moieties are bound to the support via strong C–C bonds. To test the performance of the new polymer-supported (PS) BINOLs, they were reacted with titanium tetraisopropoxide to give catalysts for the oxidation of aryl methyl thioethers using t -butyl hydroperoxide in tetrahydrofuran at 0 °C. The expected sulfoxides were obtained in up to 91% ee. The results obtained with the present catalysts are comparable to those obtained with PS catalysts prepared using more elaborate syntheses, and that have the catalyst moieties bound to the support by potentially labile linking groups.