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A convenient and effective method of synthesizing 3-aryl-2-oxazolidinones from cyclic carbonates and aryl amines catalyzed by bio-catalyst adenine in the presence of Et3N under solvent-free conditions is described. The protocol is suitable for the wide scope of substrates, e.g. cyclic carbonates with or without substitutes, and aryl amines with either electron-withdrawing or electron-donating group. The products were obtained in good to excellent yields under the optimal conditions, even in steric hindered cases. The effect of reaction time, temperature, loading of catalyst, and amount of starting materials in the reaction were investigated, and the reaction mechanism is discussed. [ABSTRACT FROM AUTHOR]

A series of di-N-heterocyclic carbene (NHC) dipalladium complexes, [PdPyBr](di-NHC) ( 2a- h), in which di-NHC represents a di-triazolylidene, featuring a 1,4-xylylene spacer between the carbene units, have been prepared from the reactions of the corresponding ditriazolium bromides with PdCl and excess NaBr as an additive in the presence of KCO in pyridine. All of the complexes were fully characterized by NMR spectra, IR and elemental analyses. The molecular structure of 2b was determined by X-ray diffraction study, showing the intermolecular hydrogen bonding of Br···H-C. The influences of size of ligands on the catalytic activity have been investigated in the Heck reaction of styrene with bromobenzene. The complex 2g showed the best catalytic activity, and it is active for various aryl bromides with different electronic and steric properties and styrenes with both electron-donating and electron-withdrawing groups. [ABSTRACT FROM AUTHOR]

A novel Fenton reagent, chalcopyrite CuFeS nanocrystals (NCs) with an average diameter of 10.6 ± 1 nm are synthesized by a facile solution phase method in a standard Schlenk Line, and they can efficiently degrade organic dyes (methylene blue, rhodamine B and rhodamine 6G) aqueous solution (100 mg L) within 1 min. XRD and TEM have been carried out to determine the crystal information, size, and shape of CuFeS NCs. The degradation process is investigated by UV-Vis spectroscopy, and its advantage is illustrated by comparing with bulk chalcopyrite. X-ray photoelectron spectroscopy is used to discuss its degradation mechanism. Based on this Fenton reagent, CuFeS NCs/biomass composite degradation column is made using sawdust as substrate, and it can efficiently degrade organic dyes continually (the total amount of organic dyes degraded by the column are 8.67, 8.44, and 8.64 times the amount degraded by pure CuFeS NCs, respectively). [ABSTRACT FROM AUTHOR]

Porous TiO were assembled by evaporating or refluxing TiO colloid, which was obtained by dispersing the TiO nanoparticles with a crystallite size ( d) of 3.2 nm into water or ethanol without any additives. Porous transparent bulk TiO was obtained by evaporating the TiO-CHOH colloid at room temperature for 2 weeks, while porous TiO nanospheres were assembled by refluxing the TiO-HO colloid at 80 °C for 36 h. Both of the porous TiO architectures were pore-size-adjustable depending on the further treating temperature. Porous TiO nanospheres exhibited enhanced photocatalysis activity compared to the nanoparticles. [ABSTRACT FROM AUTHOR]

The synthesis of a series of chiral Pd(L)PyBr ( 3a- 3e) and Pd(L)PyCl ( 4d and 4e) complexes from l-phenylalanine is presented (L = ( S)-3-allyl-4-benzyl-1-(2,6-diisopropylphenyl)-imidazolin-2-ylidene ( a), ( S)-4-benzyl-1-(2,6-diisopropylphenyl)-3-(naphthalen-2-ylmethyl)imidazolin-2-ylidene ( b), ( S)-4-benzyl-3-(biphenyl-4-ylmethyl)-1-(2,6-diisopropylphenyl)imidazolin-2-ylidene ( c), ( S)-4-benzyl-1-(2,6-diisopropylphenyl)-3-(naphthalen-1-ylmethyl)imidazolin-2-ylidene ( d) or ( S)-4-benzyl-1-(2,6-diisopropylphenyl)-3-(2,4,6-trimethylbenzyl)imidazolin-2-ylidene ( e). The complexes were characterized by physicochemical and spectroscopic methods, and the X-ray crystal structures of 3a- 3c and 4d are reported. In each case, there is a slightly distorted square-planar geometry around palladium, which is surrounded by imidazolylidene, two trans halide ligands and a pyridine ligand. There are π-π stacking interactions in the crystal structures of these complexes. Complex 3a showed good catalytic activity in the Cu-free Sonogashira coupling reaction under aerobic conditions. [ABSTRACT FROM AUTHOR]

A series of Pd complexes of picoline-functionalized N-heterocyclic carbenes with different substituents were synthesized. The molecular structures of selected complexes were determined by X-ray diffraction studies, showing a pseudo-square-planar structure with a Pd center surrounded by carbene, pyridine, and two chloride ligands. The influence of the different substituents on the structure and reactivity of the complexes has been studied. The catalytic properties of the complexes were investigated in the Mizoroki-Heck reaction for cross-coupling of bromobenzene with a variety of aryl halides. Their performances varied in these reactions but showed good product regioselectivities. [ABSTRACT FROM AUTHOR]

BiVO nanoparticles are prepared by molten salt method. Tetragonal BiVO completely transforms to monoclinic phase after heating in molten LiNO at 270 °C for 18 h. The average particle sizes of monoclinic BiVO varied from 30 to 52 nm while the initial ratio of BiVO to LiNO changes from 1:6 to 1:24. The photocatalytic activity is evaluated by measuring decolorization of N, N, N′, N′-tetraethylated rhodamine dye solution under visible-light irradiation. Both of the de-ethylation and chromophore cleavage are responsible for the decolorization of RB. The sample with an average particle size of 52 nm and a moderate surface area of 10 m/g exhibit the highest visible-light photocatalytic activity. The shift of Raman peak position indicates that the symmetry distortions in the local structure of the monoclinic BiVO. The variations of the local structure result in the modification of the electronic structure, which is responsible for the high visible-light photocatalytic activity. [ABSTRACT FROM AUTHOR]

Perovskite oxides have provided magical structural models for superconducting and colossal magnetoresistance, and the search for nano-scale and/or atomic-scale devices with particular property by specific preparations in the same systems has been extensively conducted. We present here the three oxidation states of manganese (Mn3+, Mn4+, Mn5+) in the perovskite oxide, La0.66Ca0.29K0.05MnO3, which most interestingly shows the rectifying effect as atomic-scale p–n junctions (namely FY-Junctions) of single crystals and films. The family of cubic perovskite oxides were synthesised by the so-called hydrothermal disproportionation reaction of MnO2 under the condition of strong alkali media. The new concept of the atomic-scale p–n junctions, based on the ideal rectification characteristic of the p–n junctions in the single crystal, basically originates from the structural linkages of [Mn3+–O–Mn4+–O–Mn5+], where Mn3+ $$ {\left( {{\text{t}}^{{\text{3}}}_{{{\text{2g}}}} {\text{e}}^{1}_{{\text{g}}} } \right)} $$ and Mn5+ $$ {\left( {{\text{t}}^{{\text{2}}}_{{{\text{2g}}}} {\text{e}}^{{\text{0}}}_{{\text{g}}} } \right)} $$ in octahedral symmetry serve as a donor and an acceptor, respectively, corresponding to the localized Mn4+ $$ {\left( {{\text{t}}^{{\text{3}}}_{{{\text{2g}}}} {\text{e}}^{{\text{0}}}_{{\text{g}}} } \right)} $$ . [ABSTRACT FROM AUTHOR]

In this work, ZnO microrods with etched surface are prepared by two-step hydrothermal reaction. ZnO microrods are prepared firstly by decomposing LHS-Zn under hydrothermal conditions. It is found that the (0001)-Zn face of ZnO microrods will dissolve partly due to the existence of LHS-Zn during further hydrothermal treatment, and ZnO microrods with etched surface are obtained. X-ray powder diffraction is used to determine the crystal structure, and scanning electron microscopy is used to observe the morphology of products. The photoluminescence spectra are investigated. [ABSTRACT FROM AUTHOR]