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A selective extraction process for recovering vanadium (IV) over chromium was proposed with use of a mixed extractant consisting of di(2-ethylhexyl) phosphate (D2EHPA) and tri-n-butyl phosphate (TBP). The influence of various factors, which included the initial aqueous pH value, the concentration of leach solution and D2EHPA, phase ratio (O/A), extraction equilibrium time and extraction temperature in the extraction process on the separation of V and Cr was investigated. Under the condition of the optimum extraction, vanadium extraction was above 94.0%. Meanwhile, under the optimum stripping conditions, the vanadium stripping was above 93.0% utilizing 1.5 mol/L sulfuric acid as the effective stripping reagent. The regeneration and reusability of the loaded organic phases after stripping were discussed. In addition, continuous three-stage extraction and stripping strategy indicated that the aggregate loss of vanadium was 0.885% and that the purity of vanadium was more than 99.9%. Under the condition of the optimum precipitation, when the pH value of the stripping solution was adjusted to 7.0 with ammonia water, the precipitation efficiency reached 99.93%. The calcination conditions (above 680 °C in air) were finally determined by TG-DTA and TG-MS experiments, and the V2O5 obtained by calcination was characterized by XRD. Additionally, a method for detecting impurity elements in vanadium matrix without interference was established. The recovery technology has practical significance in enlarging production scale, reducing specific energy consumption and cost, and realizing automatic control in vanadium leaching process. [ABSTRACT FROM AUTHOR]

Functional aerogels composed of regenerated cellulose and tungsten oxide were fabricated by implanting tungsten-oxide nanodots into regenerated cellulose fiber. This superfast photochromic property benefitted from the small size and even distribution of tungsten oxide, which was caused by the confinement effect of the regenerated cellulose fiber. The composite was characterized using XRD and TEM to illustrate the successful loading of tungsten oxide. The composite turned from pale white to bright blue under ambient solar irradiation in five seconds. The evidence of solar absorption and electron paramagnetic resonance (EPR) demonstrated the fast photochromic nature of the composite and its mechanism. Furthermore, carbon fiber filled with preferential growth tungsten-oxide nanorods was obtained by annealing the photochromic composite in a N2 atmosphere. This annealed product exhibited good absorption across the whole solar spectrum and revealed an excellent photothermal conversion performance. The water evaporation rate reached 1.75 kg m−2 h−1 under one sun illumination, which is 4.4 times higher than that of pure water. The photothermal conversion efficiency was 85%, which shows its potential application prospects in seawater desalination. [ABSTRACT FROM AUTHOR]

Protein phosphorylation regulates and controls protein activity and function, which is the most basic and important part in organisms' lives. However, the low abundance and ionization inhibition of phosphopeptides make it difficult to understand and analyze the protein phosphorylation mechanism. In this study, we synthesize a core‐shell structured magnetic Ti4+‐based immobilized metal ion affinity chromatography material for highly selective enrichment of phosphopeptides. The introduction of negatively charged carbon layer increases the specific surface area and avoids loss of the immobilized Ti4+ during sample loading and washing. The synthesized magnetic superhydrophilic extractant is employed to separate and enrich phosphopeptides from standard protein digests coupled with MALDI‐TOF MS. It exhibits excellent enrichment performance of high selectivity (1 : 2000 molar ratio of β‐casein and BSA), sensitivity (low detection limit of 4 fmol) and preferable reusability (at least 12 times) as well as excellent adsorption capacity of 142.5 mg ⋅ g−1 and high recovery rate of 85.6 %. Moreover, sixteen phosphopeptides and four endogenous phosphopeptides can be accurately identified from non‐fat milk and human serum, further indicating the great potential and bright application in phosphoproteomics analysis. [ABSTRACT FROM AUTHOR]

Chitosan (Cts), a positively charged natural polysaccharide, is employed to functionalize mesoporous titanium dioxide (mTiO2) nanoparticles. The prepared Cts/mTiO2 composite was used as a stationary phase to coat the inner wall of fused‐silica capillary and obtain uniform Cts/mTiO2 film. The Cts/mTiO2 film is applied to detect and enrich phosphopeptides in complex biological samples based on typical in‐tube solid phase microextraction (IT‐SPME) system. This unique Cts/mTiO2 film exhibits excellent enrichment performances of high selectivity (β‐casein and BSA in molar ratio of 1 : 1000), sensitivity (detection limit as low as 40 fmol of β‐casein tryptic digest solution) and high adsorption capacity (124.5 μg mg−1). Meanwhile, the Cts/mTiO2 film possesses preferable reusability and can be reused more than 10 times. These results confirm that the Cts/mTiO2 film possesses potential and satisfactory prospects in phosphoproteomics analysis. [ABSTRACT FROM AUTHOR]

A MOF material has been grown on metallic transition metal nitride for electrocatalytic OER. The as-prepared hierarchical NiFe-MOF@Ni3N nano/microsheet array electrocatalyst exhibits a low overpotential of 281 mV at a current density of 200 mA cm−2 with a remarkable stability of 50 h. [ABSTRACT FROM AUTHOR]

Self-supported nickel–iron nitride microsheet arrays coated with carbon are grown on commercial Ni foam (NixFeyN@C/NF) and used as an electrocatalyst for splitting of alkaline seawater. The porous architecture and superhydrophilic/superaerophobic surface ensure sufficient exposure of active sites and mass transfer. The synergetic coupling effect between the carbon coating and NixFeyN facilitates electron transport. The optimal anode (Ni3FeN@C/NF) and cathode (Ni3N@C/NF) electrocatalysts are employed to assemble a two-electrode seawater electrolyzer for overall alkaline seawater electrolysis, which delivers a large current density of 500 mA cm−2 at a low cell voltage of 1.91 V. The superior corrosion-resistance and electron conductivity of the electrocatalyst are responsible for its excellent durability up to 100 hours. This result suggests that transition-metal nitrides coated with carbon offer an effective route to fabricate high-performance and durable hybrid electrocatalysts for hydrogen production from seawater electrolysis. [ABSTRACT FROM AUTHOR]

Low-cost, efficient and stable electrocatalysts are required for large-scale production of hydrogen by industrial scale water electrolysis. We report here a hybrid bifunctional electrocatalyst, composed of amorphous NiFe LDH nanosheets and metallic Ni3N microsheet arrays grown on Ni foam for water splitting in alkaline electrolyte. This electrocatalyst possesses a typical 3D hierarchical heterostructure architecture and affords abundant exposed active sites. The strong coupling and synergistic effects between the NiFe LDH nanosheets and the Ni3N microsheet arrays provide a robust integrated structure and fast electron transfer. The superhydrophilic/superaerophobic properties of the electrocatalyst promote the mass transfer particularly at a large current density. By employing the NiFe LDH@Ni3N/NF as a bifunctional electrocatalyst for overall water splitting, an alkaline aqueous electrolyzer exhibits a low cell voltage of 1.80 V at a current density of 500 mA cm−2 with a remarkable durability of 100 h. The bifunctional NiFe LDH@Ni3N/NF electrocatalyst is a very promising candidate for scale-up industrial implementation of hydrogen production due to its excellent catalysis activity and high stability. [ABSTRACT FROM AUTHOR]

Hexagonal (NH4)xWO3 has emerged as a promising photothermal agent in recent years due to the charge compensation reaction when cation intercalation occurs. We chose the ammonium ion to intercalate into the hexagonal crystal channel of tungsten oxide because of its appropriate ion radius and unique interaction with the hexagonal channel. The transmission electron microscope image shows that the morphology of the as‐prepared (NH4)xWO3 is a nanorod with a 10 nm radius and 50 nm length. The product exhibits strong absorption across the whole near infrared and ultraviolet light spectrum, as well as part of the visible light spectrum. Moreover, it exhibits a photothermal conversion efficiency up to 69.3 % at 808 nm with good photothermal stability, and features excellent biocompatibility during the co‐culture process with MC3T3‐E1 cells. Ammonium was intercalated into the hexagonal crystal channel of tungsten oxide to produce hexagonal (NH4)xWO3 as nanorods with a 10 nm radius and 50 nm length. The product exhibits strong absorption across the whole near infrared and ultraviolet light spectrum, as well as part of the visible light spectrum. Moreover, it exhibits a photothermal conversion efficiency up to 69.3 % at 808 nm with good photothermal stability, and features excellent biocompatibility during the co‐culture process with MC3T3‐E1 cells. [ABSTRACT FROM AUTHOR]

The design of efficient catalysts for the selective oxidation of sp3 C–H bond with air at low temperature is of great importance to the scientific and industrial community. In this work, we design a CeO2–δ modified CuFe2O4 catalyst by a post‐modification method for the selective oxidation of fluorene under an air atmosphere and N‐hydroxyphthalimide (NHPI) at 60 °C. HRTEM results indicate that CeO2–δ nanoclusters sized around 5 nm are successfully modified on the surface of CuFe2O4. XPS and H2‐TPR results show that CeO2–δ modification would favor oxygen transfer at lower temperature due to the synergetic effect between CuFe2O4 and CeO2–δ with rich Ce3+/Ce4+ couples. The results demonstrate that CuFe2O4@CeO2–δ‐0.05 with 4.20 wt.‐% Ce present the best catalytic performance with 94 % conversion of fluorene and excellent reusability at least five times. It is anticipated that the modification of CeO2–δ nanoclusters on the surface leads to increased oxygen activation and transfer to CuFe2O4, which favors the activation of NHPI to phthalimide‐N‐oxyl (PINO) radicals and exhibits an improved catalytic performance. Our results provide some guidance on the design of efficient catalysts by the surface modification strategy. CeO2–δ modification with 4.20 wt.‐% Ce on the surface of CuFe2O4 nanoparticles favors oxygen transfer at lower temperature and leads to better catalytic activity than that of pure CuFe2O4 for the aerobic selective oxidation of fluorene due to the synergetic effect between CuFe2O4 and CeO2–δ with Ce3+/Ce4+. [ABSTRACT FROM AUTHOR]

Abstract: An effective three‐component fixation of atmospheric CO2 with readily available 1,2‐dichloroethane and aromatic amine toward oxazolidinones catalyzed by in situ NHC was developed. The reaction occurred in good to excellent yields with good generality and wide functional group tolerance, including challenging steric hindered substituted‐dichloroethane (e.g. 1,2‐dichloropropane and 2,3‐dichlorobutane). The catalytic system is not sensitive to air and moisture, and high yield of oxazolidinone was achieved even with about 0.3 atm of pressure of carbon dioxide. The mechanistic study suggests that the reaction catalyze by in situ NHC via NHC‐CO2 adduct, 1‐butyl‐3‐methylimidazolium‐2‐carboxylate as intermediate and aminochloride involves in reaction pathways. The catalyst can be recycled for at least 3 times without obvious loss of catalytic activity. The protocol is also effective to prepare six‐membered 3‐aryl‐1,3‐oxazinan‐2‐one and even seven‐membered 3‐aryl‐1,3‐oxazepan‐2‐one, when 1,3‐dichloropropane and 1,4‐dichlorobutane was employed. [ABSTRACT FROM AUTHOR]

It is highly desirable to develop new semiconductors for the photocatalytic reduction of CO2 to CH4 and CO to solve greenhouse effect and energy issues. Defect pyrochlore oxides have a flexible composition and the electron/hole mobility can be manipulated by introducing foreign cations into the structure. Through Sn doping into the defect pyrochlore oxide KNbWO6·H2O, we successfully obtained a 2-times higher photocatalytic activity for converting CO2 to CO, CH4 and O2 compared to the original KNbWO6·H2O. According to the data from UV-vis, photoluminescence, and hydroxyl radical amount-related fluorescence spectra, and CO2 adsorption, the improved photocatalytic activity can be attributed to the extended visible light response, the enhanced charge separation and the improved CO2 adsorption due to Sn doping. Our results provide a new strategy for developing high-performance photocatalysts. [ABSTRACT FROM AUTHOR]

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]

W18O49 with a tunable oxidation state was prepared by addition of NaNO3 or NaBH4 as a redox agent in the solvothermal system. The addition of redox agents has no influence on the crystallization of W18O49. The obtained W18O49 structures keep their morphology as a bundle of nanowires with a regular hexagonal on the cross-section. W18O49 exhibits strong valence-dependent absorption features in the near-IR region. Reduced W18O49 with more W5+ has a higher concentration of oxygen vacancies, which enhances the localized surface plasmon resonance effect. Reduced W18O49 exhibits a high photothermal conversion efficiency of 59.6 % and has good photothermal stability. [ABSTRACT FROM AUTHOR]

The di-N-heterocyclic carbene (NHC) dipalladium complexes, [(PdPyBr2)2(di-NHCimi)] and [(PdPyBr2)2(di-NHCtri)], di-NHCimi and di-NHCtrirepresent an imidazolylidene and a triazolylidene, respectively, featuring a 1,4-xylylene spacer between the carbene units, have been prepared. The influences of the imidazolylidene and triazolidene backbone and different substituents on the catalytic activity have been investigated in the Mizoroki-Heck reaction of styrene with bromobenzene. [ABSTRACT FROM AUTHOR]

An extremely stable Tb coordination polymer, TbL2 [HL = 4-(pyrimidin-5-yl)benzoic acid], was synthesized. It exhibits high thermal and chemical stability. TbL2 is a visual multiresponsive luminescent probe that can selectively detect F- among the same main-group anions as well as various pollutant phosphorus anions. [ABSTRACT FROM AUTHOR]

In this work, a novel environmentally friendly approach to deposit TiO2 films via an aqueous process is developed. The atomic force microscopy (AFM) measurement indicates that water-dispersed TiO2 nanocrystals (NCs) show excellent film-forming properties on an ITO-coated glass substrate. In addition, the femtosecond transient absorption (TA) and conductivity measurements suggest that the aqueous-processed TiO2 film shows excellent electron extraction ability and good conductivity. The aqueous-processed polymer/NC hybrid solar cells based on the aqueous-processed TiO2 electron extraction layer present superior photovoltaic performance and a PCE of 5.53% is achieved, which is the highest for hybrid solar cells fabricated via an aqueous process. Finally, the solar cells with the aqueous-processed TiO2 electron extraction layer exhibit better humidity resistance compared to the TiO2 film deposited via a sol–gel method. [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 structure of nanoparticles plays a critical role in dictating their material properties. Gold is well known to adopt face-centered cubic (fcc) structure. Herein we report the first observation of a body-centered cubic (bcc) gold nanocluster composed of 38 gold atoms protected by 20 adamantanethiolate ligands and two sulfido atoms ([Au38S2(SR)20], where R=C10H15) as revealed by single-crystal X-ray crystallography. This bcc structure is in striking contrast with the fcc structure of bulk gold and conventional Au nanoparticles, as well as the bi-icosahedral structure of [Au38(SCH2CH2Ph)24]. The bcc nanocluster has a distinct HOMO-LUMO gap of ca. 1.5 eV, much larger than the gap (0.9 eV) of the bi-icosahedral [Au38(SCH2CH2Ph)24]. The unique structure of the bcc gold nanocluster may be promising in catalytic applications. [ABSTRACT FROM AUTHOR]

The structure of nanoparticles plays a critical role in dictating their material properties. Gold is well known to adopt face-centered cubic (fcc) structure. Herein we report the first observation of a body-centered cubic (bcc) gold nanocluster composed of 38 gold atoms protected by 20 adamantanethiolate ligands and two sulfido atoms ([Au38S2(SR)20], where R=C10H15) as revealed by single-crystal X-ray crystallography. This bcc structure is in striking contrast with the fcc structure of bulk gold and conventional Au nanoparticles, as well as the bi-icosahedral structure of [Au38(SCH2CH2Ph)24]. The bcc nanocluster has a distinct HOMO-LUMO gap of ca. 1.5 eV, much larger than the gap (0.9 eV) of the bi-icosahedral [Au38(SCH2CH2Ph)24]. The unique structure of the bcc gold nanocluster may be promising in catalytic applications. [ABSTRACT FROM AUTHOR]

Carbon modified lithium titanate (Li4Ti5O12) anode nanocrystals for Li-ion batteries were synthesized by directly treating the titanium alkoxide and lithium acetate ethanol solution via the Reaction under Autogenic Pressure at Elevated Temperature (abbreviated to RAPET). The mixture of the liquid precursors decomposed during the RAPET process and then reacted in situ and transformed into carbon-modified Li4Ti5O12 anode nanocrystals. The organic moieties in the titanium alkoxide and the lithium salt provided both the oxygen and carbon for the synthesis. The resulting products were characterized by X-ray diffraction (XRD), elemental analysis, scanning electronic microscopy (SEM), high resolution transmission electron microscopy (HR-TEM), nitrogen adsorption–desorption measurements, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge–discharge testing. The influences of the titanium alkoxide precursors, i.e. the length of the alkoxy group, on the properties of the final products and the presence of the in situ resulting carbon on the electrochemical performance have been investigated. [ABSTRACT FROM AUTHOR]

Semiconductor gas sensors play important roles in detecting toxic gases in various workplaces for human safety. The gas-sensing characteristics of highly orientational CdS dendrite (HOCSD) sensors were investigated. The results showed that the HOCSD sensors exhibited an excellent response and high response speed to HCOOH and N2H4, compared to HCHO and n-BuNH2. The high performance of the HOCSD sensors towards HCOOH and N2H4 detection could be attributed to two factors: the improved diffusion and adsorption/desorption ability of the CdS dendrites, and the synergistic effect of the reduction ability and hydrogen bonds of detected gases. Moreover, it is believed that the HOCSD sensors could be potentially applied to detect the HCOOH and N2H4 with high response, fast response speed and good repeatability. [ABSTRACT FROM AUTHOR]

The inner structure of W18O49 mesocrystals was observed by electron microscopy with the help of ultramicrotomy and focused ion beam techniques. The results showed that these mesocrystals contain irregular mesopores formed through partial fusion of self-assembled nanowires, and consequently have long-range structural ordering in one dimension and short-range ordering in the other two dimensions. The W18O49 mesocrystals exhibit superior performance in gas sensing applications, which is considered to be associated with the presence of more oxygen vacancy sites in the unique mesoporous structure. [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]

Air-stable metallic Co nanoparticles were incorporated into the pores or anchored onto the external surface of an ordered mesporous carbon/SBA-15 composite by simply treating the cobalt precursor-impregnated surfactant-containing SBA-15 via the Reaction under Autogenic Pressure at Elevated Temperature (abbreviated to RAPET) process, resulting in bifunctional Co@carbon/SBA-15 composites. Surfactant-containing mesoporous SBA-15 (denoted as surf-SBA-15 composite) was firstly impregnated with a cobalt precursor solution and then calcined under autogenic pressure at elevated temperature using a Swagelok-like high-temperature autoclave in an N2 atmosphere. During the RAPET process, the cobalt precursor impregnated into the channel of the surf-SBA-15 composites decomposed and was reduced by the surfactant species, meanwhile, the surfactant, which was used as a soft template for the formation of mesoporous silica, was carbonized and coated onto the internal and the external surface of mesoporous silica and partially onto the incorporated metallic Co nanoparticles, forming Co nanoparticles encapsulated by a mesoporous carbon/SBA-15 composite (mesoporous Co@carbon/SBA-15) in situ. The products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption–desorption measurements and X-ray diffraction (XRD). The influences of the concentration of cobalt precursors on the morphologies and the magnetic properties of the mesoporous Co@carbon/silica composites were studied. The adsorption/separation ability of the magnetic mesoporous composite to organic guest molecules and the stability of the nanosized metallic Co decorations in air or in an acid environment were also investigated. [ABSTRACT FROM AUTHOR]

A series of N-aryl or N-methyl substituted bisimidazolium dichloride or dibromide salts with different alkyl bridge lengths (n = 1–4) have been synthesized starting from N-arylimidazoles or N-methylimidazoles with dialkyl bromides or the less expensive but less reactive dialkyl chlorides under solvent-free conditions. This green protocol provided most bisimidazolium chloride and bromide salts in good yields, and the reaction time was shortened to a few hours. In two examples, we showed either bisimidazolium dichloride (1a) or dibromide salt (3c) can be easily converted to the corresponding dihexafluorophosphate salt (1a′ or 3c′) in near quantitative yield. [ABSTRACT FROM PUBLISHER]

An efficient C-N coupling reaction of aryl chlorides or bromides with imidazole was successfully performed with cheap and commercially available catalytic system Cu(I)/HMTA. Both aryl bromides and aryl chlorides have been effectively catalyzed by Cu/HMTA, giving products in moderate to good yields. Moreover, aryl halides bearing either electron-withdrawing groups or electron-donating groups could be used in the reaction. [image omitted] [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]

Two novel pyrrole-functionalized bis(benzoimidazolium) salts, which are novel NHC-pyrrole-NHC C-N-C Pincer proligands were synthesized in high yield. Both of these compounds are fully characterized by 1H and 13C NMR, IR and elemental analysis. [ABSTRACT FROM AUTHOR]

A novel tridentate chiral imidazolium hexafluorophosphate, a precursor for N-heterocyclic carbene (NHC) ligand, was synthesized from (S)-proline in five steps in 24% overall yield. The compound was characterized by NMR and elemental analysis. Its molecular structure was determined by X-ray diffraction analysis. This chiral compound has two stereogenic centers which are within two chelating side chains and its specific rotation is -19.6°. [ABSTRACT FROM AUTHOR]

Two series of bistriazolium dibromides with different alkyl bridged length (n = 2-4) were synthesised through a simple solvent-free method. Six of these compounds were prepared from the reaction of 1-R-1H-1,2,4-triazole with dibromoalkane in moderate to excellent yield (45-98%). However, the other six compounds were prepared from the reaction of alkyl bridged bistriazole with bromoalkane in 55-99% yield. All compounds are new and were fully characterised by IR, NMR and elemental analyses. [ABSTRACT FROM AUTHOR]