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A simple and efficient methodology for the synthesis of large sterically hindered triarylamines in a single step was developed. A direct N,N-diarylation of 8-aminoquinoline with sterically hindered...

Simultaneous photocatalytic reactions of H2 evolution and real wastewater degradation have drawn much attention to practical energy and environmental applications. While these applications of photocatalyst often suffer from the high charge-carrier recombination and poor efficiency in reactants activation, resulting in unsatisfactory photocatalytic activity or need expensive platinum co-catalyst. Here, the unsaturated iron ion based coordination polymer (FeTMT) with weak Fe-N sites has been fabricated by a facile wet-chemical method. It exhibits outstanding photocatalytic performance for the simultaneous production of H2 (1272 μmol g-1 h-1) and degradation of real wastewater from brewing liquor (degradation efficiency is 60%) without using any cocatalyst, which is larger than that reported system. The density functional theory (DFT) calculations revealed that the unsaturated Fe-N bridge could transfer the electrons from C3N3S3 rings to Fe3+, boosting the separation and transportation efficiency of charge carriers. On the other hand, the N functional group close to the metal centers in FeTMT could regarded as a proton relay to enhance the surface of hydrophily. Further in-situ test demonstrated that unsaturated Fe sites could adsorb H+ to form H-Fe-H bond, while Fe-N sites serve as the catalytic active centers in FeTMT. This finding opens an avenue to construct a novel coordination polymer and deep understanding for the practical industrial photocatalysis application

A new tripodal C-anionic ligand, 2-{bis(benzothiazolyl)(methoxy)methyl}phenyl (L), was stably generated by the reaction of the ligand precursor (L'), the corresponding bromide (2-BrC6H4)(MeO)C(C7H4NS)2 (C7H4NS = 2-benzothiazolyl), with nBuLi at -104 °C in the presence of TMEDA (N,N,N',N'-tetramethylethylenediamine). The ligand lithium salt reacted with BiCl3 to give a 2 : 1 complex L2BiCl. A 1 : 1 complex LBiCl2 was obtained in good yield by the redistribution reaction between L2BiCl and BiCl3. X-ray diffraction analysis revealed that the ligand L coordinated in an expected κ3-C,N,N' coordination mode in LBiCl2, while it coordinated in κ3-C,N,O and κ2-C,O coordination modes in L2BiCl. The ligand precursor reacted with BiX3 (X = Cl, Br) to give 1 : 1 complexes L'BiX3 and was found to act as a neutral tripodal C(π),N,N-ligand.

Rational tailoring of the atomic structure of photocatalysts with multiple functions to enhance the carrier transfer efficiency and surface activation of carbon nitride (C3N4) is promising and a challenge. Here, we make the first report of a facile strategy to construct amphiphilic carbon and C–O–C chain linked terminal melem units in functional carbon nitride (COCN) via copolymerizing formaldehyde with melem. By integrating the amphiphilic carrier bridge of carbon and C–O–C chains into the framework, the photogenerated carrier mobility and activated species (superoxide radicals, singlet oxygen) as well as surface interaction are significantly improved. Consequently, the optimal tailoring of C3N4 attains superior photocatalytic activity for hydrogen production (34.9 μmol h−1) and selective oxidation of sulfide to sulfoxide using air (nearly 100% conversion and selectivity after 3 h of illumination), which is about 7 times higher than that of pristine C3N4. This study provides deep insight into and strategies for the atomic tailoring of carrier transfer and surface reaction over organic-based photocatalysts.

The introduction of oxygen vacancies (Ov) has been regarded as an effective method to enhance the catalytic performance of photoanodes in oxygen evolution reaction (OER). However, their stability under highly oxidizing environment is questionable but was rarely studied. Herein, NiFe-metal-organic framework (NiFe-MOFs) was conformally coated on oxygen-vacancy-rich BiVO4 (Ov-BiVO4 ) as the protective layer and cocatalyst, forming a core-shell structure with caffeic acid as bridging agent. The as-synthesized Ov-BiVO4 @NiFe-MOFs exhibits enhanced stability and a remarkable photocurrent density of 5.3±0.15 mA cm-2 at 1.23 V (vs. RHE). The reduced coordination number of Ni(Fe)-O and elevated valence state of Ni(Fe) in NiFe-MOFs layer greatly bolster OER, and the shifting of oxygen evolution sites from Ov-BiVO4 to NiFe-MOFs promotes Ov stabilization. Ovs can be effectively preserved by the coating of a thin NiFe-MOFs layer, leading to a photoanode of enhanced photocurrent and stability.

We disclose a novel method for the synthesis of fluorescent N,N'-chelate organoboron compounds in high efficiency by treatment of aminoquinolates with NaBAr4/R'COOH in the presence of an iodine cat...

Bromine mediation has been regarded as one of the most efficient ways to activate and convert methane to useful organics. This article reports the effects of active components (Rh, Ru, Pd and Pt) and supports (SiO2, MgO and Al2O3) on the catalysis of methane oxybromination. Among the prepared catalysts, Rh/SiO2 is the best in performance (CH4 conversion of ca. 20% and CH3Br selectivity exceeding 70%). The results reveal that support type has a notable influence on the catalytic performance of Rh, especially on product distribution. The high selectivity to CH3Br over Rh/SiO2 is attributed to its low propensity for CH3Br oxidation. It was found that Rh small in particle size shows high catalytic activity and CH3Br selectivity. Although silicalite-1 zeolite suffers from a certain degree of structural damage due to the presence of high temperature steam, the use of silicalite-1 as support results in a performance comparable to that of Rh/SiO2.

Submicron-sized SAPO-34 zeolites were synthesized via nanosheet seed-assisted method using cheap diethylamine as the template. Only 2 wt % seeds are needed to obtain the submicron-sized SAPO-34 (ca. 700 nm). Further increase of seed dosage has little effect on reducing the crystal size but leads to an increase of acidity. Among the as-prepared samples, S-0.3-2% (SiO2/Al2O3 = 0.3, 2 wt % seed) shows the best catalytic performance (CH3Br conversion of up to 95%, ethylene and propylene selectivity of 94%, and a lifetime of over 125 min) ever reported in the studies of CH3Br conversion to light olefins. The results undoubtedly demonstrate that lifetime and olefin selectivity are highly dependent on the particle size and acidity of SAPO-34 zeolites. The decrease of particle size and acidity is beneficial to alleviating carbon deposition, resulting in enhanced catalyst lifetime. In addition, the decrease of particle size and lowering of acidity could diminish the second hydrogen transformation reactions of olef...

Metal-organic framework (MOF) is one of the most promising porous materials in photocatalysis. In this study, copper was deposited on as well as encapsulated in a semiconductor-like MOF (UiO-66) to fabricate the Cu/Cu@UiO-66 catalyst via an advanced double-solvent approach followed by one-step reduction. Even with ultralow amount of copper, Cu/Cu@UiO-66 shows significantly enhanced photocatalytic activity as well as stability for partial oxidation of aromatic alcohols under visible light irradiation. The result is attributed to the integration of plasmonic effect (Cu nanoparticles on UiO-66) and Schottky junction (Cu quantum dots encapsulated in UiO-66) which can be considered as a promising noble-metal-free way for the enhancement of visible-light-driven photocatalytic activity of MOFs.

We report the synthesis of mesoporous alumina (MA)-supported sodium tripolyphosphate (STPP)/chitosan (Ch) composite (denoted as MA@STPP/Ch) by a layer-by-layer self-assembly method. The multilayered MA@STPP/Ch is nontoxic and shows excellent CO2 adsorption capacity (maximum: 278.96 mg g−1 at 50 °C) and reusability, better than that of MA (97.24 mg g−1 at 50 °C). The enhanced CO2 adsorption could be ascribed to the synergism between porous structure and functional groups of Ch.

Bismuth oxyhalides (BiOX), as a typical photocatalytic material, have attracted much attention due to their unique layered structure, non-toxicity and excellent stability. However, the photocatalytic performance of BiOX is limited by their weak light absorption ability and rapid recombination of photo-generated carriers. In the present work, first-principles calculations have been performed to comprehensively explore the structural, electronic and optical properties of black phosphorus (BP)/BiOX (X = Cl, Br, I) heterostructures, revealing the inherent reasons for their enhanced photocatalytic performance. By combining band structures and work function analysis, the migration paths of photo-generated electrons and holes are obtained, proving a direct Z-scheme photocatalytic mechanism in BP/BiOX heterostructures. Moreover, the BP/BiOX heterostructures have decent band edge positions, which are suitable for photocatalytic overall water splitting. Compared with single BiOX, the light absorption performance of BP/BiOX heterostructures is significantly improved, in which BP/BiOI exhibits the highest optical absorption coefficient among the BP/BiOX heterostructures. Meanwhile, the better carrier migration performance of the BP/BiOX heterostructures is attributed to the reduction in effective mass. The present work offers theoretical insight into the application of BP/BiOX heterostructures as prominent photocatalysts for water splitting.

Herein, we developed a protocol for the efficient synthesis of 3-aryl benzofuran-2(3H)-ones under solvent-free conditions from phenols and mandelic acids using Ni(OTf)2 as a catalyst. A diverse range of mandelic acids and phenols undergo C–H/O–H bond dual functionalization to generate products in moderate to good or excellent yields. The nickel catalyst can be easily recycled in a test of three runs at the scale of 10 mmol without significant decline in the product yield. It was demonstrated that the yield of the desired product could be increased, for example, in the synthesis of the antioxidant Irganox HP-136 to a scale of 166 g.

A protocol for the chelation-assisted C-N cross-coupling of phosphinamides and aryl boronic acids with copper powder under an oxygen atmosphere is reported. This reaction proceeds efficiently to afford fully substituted unsymmetrical N-arylation phosphinamides at room temperature in excellent yields. Diverse unstable functional groups on the benzene ring of aryl boronic acids such as vinyl, formyl, acetyl, sulfonyl, acetylamino, cyano, nitro, and trifluoromethyl can be accommodated.

Photocatalytic selective oxidation organic compounds to produce high additional value of products with air hold great promising in the chemical industry, but the photocatalyst often suffered from serious recombination of charge carriers, limited conversion efficiency, poor oxygen adsorption and stability. Here, a novel bismuth complexes with N/S coordination based metallopolymer (BiTMT) has been prepared by a facile wet-chemical method. It is confirmed that the weak interaction of Bi−N bonds not only acted as electron trapping site and charge bridge to facilitate the separation of photogenerated charge carrier, but also played an important role in the adsorption and activation of oxygen from air. BiTMT exhibits excellent conversion efficiency and stability in the selective oxidation of styrene using air as oxidant under visible light irradiation. This finding opens an avenue to design functional sites for photocatalytic selective oxidation and other applications.

A palladium-catalyzed Sonogashira-type coupling between arylsulfonyl hydrazides and terminal alkynes via Ar(C)-S bond cleavage is disclosed, which enables the general synthesis of functionalized internal alkynes, especially the Br-substituted ones, in good to excellent yields under acid- and base-free conditions.

The Iodine-mediated oxidative intramolecular amination of anilines via cleavage of unactivated (sp3)C–H and N–H bonds for the production of indolines is described. This transition-metal-free approach provides a straightforward strategy for producing (sp3)C–N bonds for use in the preferential functionalization of unactivated (sp3)C–H bonds over (sp2)C–H bonds. The reaction could be performed on a gram scale for the synthesis of functionalized indolines.

A Cobalt porphyrin conjugated porous polymer (Co/PCP) was obtained by hybrid polymerization of a mixture of Co(II)(5,10,15,20-tetrakis(4-bromophenyl)-21H,23H-porphyrin) (CoTBPP) and 5,10,15,20-tetrakis(4-bromophenyl)-21H,23H-porphyrin (TBPP) (3:7 M ratio) with the coupling reagent of p-phenyldiboric acid. This Co/PCP was carbonized at 400 °C and the obtained catalyst (denoted as Co3O4@PNC-400) was composed of Co3O4 nanoclusters wrapped in the nitrogen-carbon materials. This catalyst has an extremely high catalytic activity for the aerobic oxidation of C–H bonds. It can efficiently catalyze the oxidation of the C–H bonds in toluene and cyclohexane with high conversion and high selectivity of (alcohol + aldehyde), (alcohol + ketone) compounds, respectively. When heat-treated at 400 °C, the porous framework structure of the porphyrin polymer was partially retained, and the highly active Co3O4 nanoclusters were generated in situ. The reaction of C N to C N and connection with the Co3O4 nanoclusters also occurred. Co3O4@PNC-400 has obvious synergistic catalytic effect between Co3O4 and nitrogen-carbon framework during the catalytic reaction. The defective structure caused by the migration of cobalt also greatly improved the catalytic activity. Co/PCPs with different cobalt contents were also synthesized and heat treated at different temperature. These catalysts were a new type of efficient C–H oxidation catalysts with excellent potential application value.

Functional nanosheets have attracted great attention due to their potential applications in catalysis chemistry and material science. Herein, Co3O4 nanoparticles interconnecting with nitrogen-doped carbon architectures (denoted as Co3O4/NC) was developed on nickel foam surface by a two-step solvothermal process and followed by calcination. A metal organic framework (MOF) of laminar CoMOF-NH2 was synthesized firstly by in-situ transformation of Co2(OH)3Cl array. Then, porous Co3O4/NC nanosheets were obtained by controlled heat treatment of CoMOF-NH2. The Co3O4/NC supported by nickel foam can be directly used as self-supported electrodes for electrocatalysis without any binders. As-synthesized Co3O4/NC acts as effective catalysis for oxygen evolution reaction (OER). Interestingly, the optimized electrochemical efficiency for OER was achieved by Co3O4/NC nanosheet with overpotentials of 235 mV and 264 mV offering current densities of 10 mA/cm2 and 100 mA/cm2, respectively. It also has a relatively low Tafel slope, which indicates the fast electron transfer kinetics of the catalyst. So Co3O4/NC nanosheet has great potential in replacing precious metal electrocatalysts in OER application.

The atom-economic and one-pot regio- and stereoselective addition of sodium arenesulfinates to either alkynes or alkenes can be achieved with an iron(III) chloride hexahydrate [FeCl3⋅6 H2O] catalytic system to afford β-haloalkenyl and β-chloroalkyl sulfones in moderate to good yields.

A Ni-catalyzed oxidative C–H/C–H cross-dehydrogenative coupling (CDC) reaction was developed for constructing various highly functionalized alkyl (aryl)-substituted thiophenes. This method employs thiophenes and aliphatic (aromatic) amides that contain an 8-aminoquinoline as a removable directing group in the presence of a silver oxidant. The approach enables the facile one-step synthesis of substituted thiophenes with high functional group compatibility via double C–H bond cleavage without affecting C–Br and C–I bonds. DFT calculations verify the importance of KH2PO4 as an additive for promoting C–H bond cleavage and support the involvement of a Ni(III) species in the reaction.

A series of manganese oxide octahedral molecular sieve (OMS-2) doped with Co, V, and Ce (Me) with molar ratio Me/Mn = 0.04 and 0.12 were prepared via a one-step reflux method, and were characterized by XRD, SEM, IR, BET, ICP, XPS, and TG techniques. The OMS-2 materials doped with Me having Me/Mn = x are denoted as Me-M(x). It was found that Ce mainly enters the tunnel structure of OMS-2 instead of K, Co mainly substitutes for Mn in the framework, and V is likely to substitution into both the Mn and K in the cryptomelane tunnel structure. The length of OMS-2 rods decreases with the decline of K+ mole fraction in the OMS-2 tunnels. Doping V and Ce markedly decreases the crystallization of OMS-2. Ce-M(0.12) shows a specific surface area (142 m2 g−1) roughly double that of OMS-2 (69 m2 g−1). All the Me-M(x) materials were tested as catalysts for the oxidation of p-chlorotoluene to p-chlorobenzaldehyde with molecular oxygen, and it is Ce-M(0.12) that shows the highest catalytic activity. The excellent performance is attributed to the large specific surface area and good mobility of oxygen species of the Ce-M(0.12) material.

A Cu-catalyzed selective aerobic heterocoupling of terminal alkynes is disclosed, which enables the synthesis of a broad range of unsymmetrical 1,3-diynes in good to excellent yields. The results disprove the long-held belief that homocouplings are exclusively favored in the Glaser-Hay reaction.

WS2 nanosheets–CdS nanorods with heterojunctions were prepared by an ultrasonic/exfoliation method using dimethylformamide as the dispersing agent. CdS nanorods were coupled with small WS2 nanosheets as a result of exfoliation. An excellent hydrogen production rate of 1222 μmol h–1 (20 mg of catalyst) was achieved over the WS2–CdS composite with a WS2-to-CdS mass ratio of 1.6:1 under visible-light irradiation (λ ≥ 400 nm). The efficient evolution of hydrogen is attributed to promotion of the separation of photogenerated charge carriers due to the presence of heterojunctions created on the surface.

The aim of “green chemistry” and “atom economy” is to utilize carbon dioxide and replace harmful reactants such as CO and phosgene for the production of cyclic carbonates. In this paper, metal-free catalysts including organic bases, ionic liquids, supported catalysts, organic copolymers and carbon materials for the synthesis of cyclic carbonates by the cycloaddition of carbon dioxide to epoxides are reviewed. Recent advances in the design of the catalysts and the understanding of the reaction mechanism are summarized and discussed. The synergistic effects of organic bases and hydrogen bond donors, organic bases and nucleophilic anions, hydrogen bond donors and nucleophilic anions and active components and supports are highlighted. The challenge is to develop metal-free catalysts suitable for carbon dioxide capture and fixation. The ultimate goal is to synthesize cyclic carbonates in a flow reactor directly using carbon dioxide from industrial flue gas at ambient temperature and atmospheric pressure. By using synergetic effects, a multi-functional approach can meet the design strategy of metal-free catalysts for carbon dioxide adsorption and activation as well as epoxide ring opening.

Photocatalysis has received much attention owing to current energy and environmental crises. The use of an appropriate photocatalyst is important to a photocatalytic process. The development of photocatalysts that absorb light over a wide range of wavelengths and efficiently separate charge carriers remains a challenge and hot research topic. With strong visible-light-absorption ability, bismuth-containing photocatalysts are of great interest to scientists. However, measures have to be taken to enhance the light absorption efficiency and to lessen the problem of the recombination of charge carriers. Known approaches are the formation of heterojunctions through (1) loading of a noble metal, (2) semiconductor combination, (3) metal and nonmetal doping, (4) carbon-based material modification, and (5) Bi metal loading. The present review summarizes recent advances in this respect. Finally, the future development and potential applications of bismuth-containing photocatalysts with heterojunctions are briefly discussed.

Triphenyl bismuth bisperfluorooctanesulfonate is an air- and water-stable Lewis acid. It exhibits high catalytic efficiency for the synthesis of nitrogen heterocycles such as diindolylmethane derivatives, dihydropyrimidinones, dihydropyridines and 1,2-disubstitued benzimidazoles under mild condition. Furthermore, it can be reused without loss of activity in a test of five cycles.This catalytic system affords a simple and efficient way for the synthesis of N-containing compounds.

Z-scheme Ag3PO4/Ag/MoO3-x photocatalyst was prepared by deposition of Ag and Ag3PO4 nanoparticles on the surface of MoO3-x nanosheets. With Ag mediation between Ag3PO4 and MoO3-x, there is efficient separation and utilization of photogenerated charge carriers. Owing to the rich presence of oxygen vacancies on the surface of MoO3-x, oxygen adsorption on the surface is enhanced. The as-prepared Ag3PO4/Ag/MoO3-x Z-scheme system shows outstanding photocatalytic activity and stability for the degradation of dyes (rhodamine B, methylene blue, as well as their mixture) and ciprofloxacin under visible light irradiation, displaying degradation rate that is 15.9, 3.4, 14.9 and 3.0 times that of MoO3-x, Ag3PO4, Ag/MoO3-x and Ag3PO4/MoO3-x, respectively. According to the results of trapping experiments, ·OH and ·O2− are the main active species, and a possible reaction mechanism has been proposed.

A site-selective metal-free dealkylative approach to synthesize aryl alkyl and symmetrical dialkyl sulfides has been developed. This procedure is convenient and has wide functional group tolerance giving rise to sulfides carrying various alkyl chains from simple alkyl sulfides and alkyl halides in good to excellent yields. This transalkylation proceeds by an ionic mechanism via sulfonium intermediates and it was proposed that dimethylacetamide (DMAC) may participate in part to promote the reaction.

A new pattern for difunctionalization of alkynes via a palladium-catalyzed regio- and stereoselective coupling-addition of propiolates with arylsulfonyl hydrazides is disclosed. The approach enables the synthesis of various highly functionalized ( E)-vinylsulfones in satisfactory yields. Arylsulfonyl hydrazides act as both aryl and sulfonyl sources via selective cleavage of Ar(C)-S and S-N bonds, which are simultaneously incorporated onto the terminal carbon atom of an alkyne molecule.

A green and efficient route for the highly-selective oxidation of saturated alpha-carbon C-H bonds in aromatic alkanes under visible-light irradiation and solvent-free conditions is developed using flower-like Bi2WO6 microspheres as catalysts.

Efficient copper-catalysed aerobic oxidative esterification of N-heteroaryl methanes with alcohols has been developed. A variety of N-heteroaryl esters including those with functional groups are produced in good to excellent yields under the present reaction conditions.

The first nickel-catalyzed phosphinylation of C–S bonds forming C–P bonds is developed. The reaction can proceed readily with the simple Ni(cod)2 at a loading down to 0.1 mol% at the 10 mmol scale. Various aryl sulfur compounds, i.e. sulfides, sulfoxides and sulfones all couple with P(O)–H compounds to produce the corresponding organophosphorus compounds, which provides an efficient new method for the construction of C–P bonds.

The mechanism of the palladium-catalyzed cross dehydrogenative coupling of P(O)–H compounds with terminal alkynes was studied. Successive ligand-exchange reactions of Pd(OAc)2 with a hydrogen phosphoryl compound and a terminal alkyne take place readily to replace the two acetates on palladium, producing the corresponding (phosphoryl) (alkynyl)palladium complexes, which upon heating decomposed to the corresponding alkynylphosphorus compound. It is also confirmed that in the stoichiometric reactions of the complexes, the configuration at phosphorus is retained. On the basis of these stoichiometric reactions, an efficient synthesis of P-chiral alkynylphosphoryl compounds via palladium-catalyzed stereoselective cross dehydrogenative coupling of P-chiral P(O)–H compounds with terminal alkynes was developed. The key palladium complexes and the stereochemistry of the chiral phosphorus compounds are all unambiguously determined by single-crystal X-ray analysis.

The first copper-catalyzed aerobic oxidative C(aryl)OH bond functionalization of catechols is reported. Under air, at room temperature, in the presence of a copper catalyst, catechols react with amines to produce the corresponding benzoxazoles in high yields. Mechanistic studies suggest that the reaction proceeds via an intriguing competitive oxidation and a synergetic catalysis between catechol and amine.

An air-stable uninuclear complex of bis(isopropylcyclopentadienyl) zirconium perfluorooctane sulfonate (1a·H2O·3THF) was successfully synthesized by the reaction of (i-PrCp)2ZrCl2 with C17SO3Ag. The compound 1a·H2O·3THF was characterized by different techniques (such as X-ray single crystal diffraction, TG-DSC, conductivity measurement and acid strength) and found to have the similar nature of water tolerance, air-stability, thermally-stability and strong Lewis-acidity with that of our previously reported binuclear and uninuclear zirconocenes perfluorooctanesulfonate. This novel complex was confirmed to be an effective catalyst with good recyclability and reusability for the direct benzylation of 1,3-dicarbonyl derivatives using alcohols as alkylating agents. Various 1,3-dicarbonyl and alcohols derivatives can participate in the reaction, affording the corresponding monobenzylated products in competitive yields as compared to its counterparts, such as Cp2Zr(OSO17)2·3H2O·THF and the traditional Lewis-acid catalysts.

Manganese-containing MFI-type Mn–ZSM-5 zeolites were prepared and characterized by XRD, UV-vis DRS, SEM, XPS, N2 adsorption–desorption, NH3-TPD and ICP-AES techniques. The zeolites show high catalytic activity and selectivity in the heterogeneous oxidation of p-chlorotoluene to p-chlorobenzaldehyde. The effects of catalyst concentration, water addition, HBr amount, as well as reaction time and temperature on product yield were investigated. Under the optimized conditions (catalyst 20 mg, p-chlorotoluene 1 mL, solvent (acetic acid) 10 mL, HBr (40 wt%) 30 mg, H2O 3 g, oxygen flow rate 50 mL min−1, time 8 h, temperature 100 °C), the Mn–ZSM-5 (Si/Mn = 48, Mn 1.7 wt%) catalyst shows p-chlorotoluene conversion of 93.8% and p-chlorobenzaldehyde selectivity of 90.5%. The excellent catalytic activity can be attributed to the distribution of Mn species and the mild acid sites.

Using O2 as the oxidant, the benzoxazole frameworks can be directly constructed from the readily available phenols and primary amines in the presence of NH4PF6 over copper under mild conditions. Mechanistic studies showed that a novel mechanism involving biphenyldiols and o-quinones very possibly takes effect in the reaction, because both can selectively give the benzoxazoles under the reaction conditions. An unprecedented unstrained Caryl–Caryl bond cleavage takes place in the reaction.

The reaction of secondary phosphine oxides R2P(O)H 1 with Cu(OAc)2 under nitrogen atmosphere produced complexes [(R2P)2O(CuOAc)2]2 2. A rapid ligand exchange took place when treating complexes 2 with NH4Cl to generate [(R2P)2O(CuCl)2]2 3 in good yields. The structures of 3 were determined by X-ray crystallography, showing that the geometries of these tetranuclear copper complexes vary with the R group of the phosphorus units. Compared to complexes 2 which are air sensitive, complexes 3 are stable under air.

A copper-catalyzed system for the amidation of carboxylic acids with tert-amines through C–N bond cleavage was developed. This protocol is practical and represents a simple way to produce functionalized amides from basic starting materials in moderate to good yields. A plausible mechanism is proposed for the reaction.

Three heterocyclic hypervalent organoantimony chlorides RN(CH2C6H4)2SbCl (2a R = t-Bu, 2b R = Cy, 2c R = Ph) and their chalcogenide derivatives [RN(CH2C6H4)2Sb]2O (3a R = t-Bu, 3b R = Cy, 3c R = Ph) were synthesized and characterized by techniques such as 1H NMR, 13C NMR, X-ray diffraction, and elemental analysis. It is found that the anti-proliferative activity detected over these compounds can be attributed to the coordination bond between the antimony and nitrogen atoms of these compounds. Moreover, a preliminary study on mechanistic action suggests that the inhibition effect is ascribable to cell cycle arrest and cell apoptosis.

Nano-fibrous zirconium-doped manganese oxide octahedral molecular sieves (denoted as Zr-OMS-2) were prepared and characterized by XRD, SEM, EDXS, FTIR, NH 3 -TPD, and N 2 adsorption-desorption techniques. The materials were used as catalysts for liquid-phase aerobic oxidation of p -chlorotoluene to p -chlorobenzaldehyde. The Zr-OMS-2 catalysts show much higher catalytic activities than OMS-2, and the Zr-OMS-2 with 6 wt% Zr content shows the highest activity, giving approximately 93% p -chlorotoluene conversion and 86% p -chlorobenzaldehyde selectivity in 10 h at 100 °C. The promotion effect of Zr is deduced to be related with the suitable acidity and the enhancement of specific surface area. In addition, effects of reaction parameters such as catalyst amount, oxygen flow, temperature and time were studied.

Herein, we report the use of cobalt sulfide (CoS2) as efficient and inexpensive co-catalyst of CdS nanorods for photocatalytic water splitting. The aim is to explore the use of earth-abundant cobalt species to replace precious metals for the photocatalytic reactions. The results of first-principles DFT simulation and planar-averaged differential charge density calculation reveal that at the CoS2/CdS interface, CoS2 has zero band gap which is a class nature of precious metals, and functions as electron trap to enhance the transfer of hot electrons from CdS to CoS2. Owing to the merits of efficient charge separation, high exposure of active sites as well as large surface area, the CoS2/CdS composites exhibit outstanding photocatalytic activity in H2 production under visible light (˜58 mmol·g−1 h−1), which is about 19 times that of CdS nanorods alone and 3 times that of 1 wt%Pt/CdS under the same conditions.

A novel copper-catalyzed selective semihydrogenation of terminal alkynes using hypophosphorous acid as hydrogen donor took place efficiently to afford the corresponding alkenes in high yields. A broad range of substituted terminal aromatic and aliphatic alkenes, including terminal dienes and enynes bearing internal triple bonds, can be efficiently synthesized by this reaction.

An air-stable Lewis acidic binuclear complex of bis(ethylcyclopentadienyl)zirconium perfluorooctanesulfonate (1a) was successfully synthesized by the reaction of (CH3CH2Cp)2ZrCl2 with C8F17SO3Ag. The complex 1a was characterized by different techniques and found to have the nature of air-stability, water tolerance, thermal-stability, and strong Lewis-acidity. In addition, its solubility was higher than that of our previously reported uninuclear zirconocene bis(perfluorooctanesulfonate). This complex showed high catalytic efficiency, good recyclability, and reusability in the one-pot three-component aza-Friedel–Crafts reactions of indoles with aldehydes and N,N-dimethylaniline. The yields of the corresponding 3-diarylmethyl indoles are higher than those from the traditional Lewis acidic catalysts.

A facile Ni-catalyzed semihydrogenation of internal alkynes to ( E )-alkenes using the cheap and easily handled hypophosphorous acid as a hydrogen donor was described. This reaction is featured by high reaction efficiency to produce the corresponding ( E )-alkenes selectively.

The utilization of organoantimony (bismuth) complexes in CO2 fixation is reviewed in this article. The efficient synthesis of cyclic carbonates from CO2 and epoxides over an organoantimony(V) catalyst was first reported in 1979. After that, several organoantimony(V) complexes were found to be active for CO2 fixation. In 2009, an organoantimony(III) complex was reported as an effective CO2 absorbent and it is the only example of this kind. The study of organobismuth complexes for CO2 fixation started in 2008, and the achievements are: (i) when organobismuth oxides, hydroxides and methoxides are used as CO2 absorbents, they are converted to carbonates, and the organobismuth carbonates can be renewed as organobismuth oxides; (ii) organobismuth complexes can be used as catalysts to transform CO2 into epoxides as cyclic carbonates at room temperature in the presence of a co-catalyst such as LiI and Bu4NI; (iii) there is the development of bimetallic organobismuth complexes that show cooperative catalytic action; (iv) there is the physical fixation of CO2 by inorganic–organic bismuth complexes; and (v) CO2 insertion into the Bi–C bond of an organobismuth complex is disclosed. Most of the above catalytic systems can be considered as “electrophile–nucleophile”. In general, the synthesis of cyclic carbonates from CO2 and epoxides catalyzed by an organoantimony (bismuth) complex follows the mechanism: the complex first reacts with CO2 to form an organometallic carbonate, then the carbonate reacts with an epoxide with ring-opening by a base (e.g., n-Bu4NI).

article i nfo Manganese-based octahedral molecular sieves (OMS-2) of rod-like, fibrous-like, dendritic-like, and nest-like morphologies were synthesized by solid-state reaction, reflux, and hydrothermal methods, respectively. The materials were characterized and tested for liquid-phase oxidation of p-chlorotoluene to p-chlorobenzaldehyde. Over nest-like OMS-2, p-chlorotoluene conversion was significantly higher than that of the others. The differences in catalytic performance are attributed to the effects of composition and structure. The high activity of nest-like is due to the high concentration of oxygen adspecies and good mobility of oxygen species, whereas the poor performance of dendritic-like is due to the presence of chromium.

Under the Atherton–Todd reaction conditions, the stereochemistry on the reaction of H-phosphinates with different nucleophiles (e.g., amines, alcohols, phenols) was investigated. All reactions took place stereospecifically with inversion of configurations at the phosphorus centers. The reaction might proceed via a phosphoryl chloride intermediate with retention of configuration at phosphorus, followed by the attack of nucleophiles from the backside of Cl to give the substitution products with inversion of configuration at the phosphorus center. A plausible mechanism was proposed for these reactions.

a b s t r a c t We report a new strategy for one-pot synthesis of potassium-loaded MgAl oxides using KOH to adjust the pH value of the reaction system. The as-prepared solid superbases were studied by N2 physisorp- tion method, energy-dispersive X-ray spectroscopy, powder X-ray diffraction, and Fourier transform infrared. The superbasic sites were characterized by the use of Hammett indicators and CO2 temperature- programmed desorption. We found that with a base strength (H-) above 26.5, the potassium-loaded MgAl oxides showed high catalytic activity for Knoevenagel condensation at room temperature. Furthermore, the higher the superbasicity and/or the more the amount of superbasic sites, the better is the catalytic activity. The findings open up a new route for the synthesis of new functional superbases using composite oxides as supports. © 2013 Elsevier B.V. All rights reserved.