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Metal-organic framework (MOF) glasses are a fascinating new class of materials, yet their prosperity has been impeded by the scarcity of known examples and limited vitrification methods. In the work described in this report, we applied synergistic stimuli of vapor hydration and thermal dehydration to introduce structural disorders in interpenetrated

Copper-catalyzed selective alkynylation with N-propargyl carboxamides as nucleophiles has been successfully developed for the synthesis of C2-functionalized chromanones. Under optimized reaction conditions, 21 examples were obtained in one-pot procedure through 1,4-conjugate addition. This protocol features readily available feedstocks, easy operations and moderate to good yields, which provides viable access to pharmacologically active C2-functionalized chromanones.

Efficient and direct conversion of methane to value-added products has been a long-term challenge in shale gas applications. Here, we show that atomically thin nanolayers of Pt with a single or double atomic layer thickness, supported on a two-dimensional molybdenum titanium carbide (MXene), catalyse non-oxidative coupling of methane to ethane/ethylene (C2). Kinetic and theoretical studies, combined with in-situ spectroscopic and microscopic characterizations, demonstrate that Pt nanolayers anchored at the hexagonal close-packed sites of the MXene support can activate the first C–H bond of methane to form methyl radicals that favour desorption over further dehydrogenation and thus suppress coke deposition. At 750 °C and 7% methane conversion, the catalyst runs for 72 hours of continuous operation without deactivation and exhibits >98% selectivity towards C2 products, with a turnover frequency of 0.2–0.6 s−1. Our findings provide insights into the design of highly active and stable catalysts for methane activation and create a platform for developing atomically thin supported metal catalysts. The challenge in non-oxidative coupling of methane lies in the activation of the first C–H bond while avoiding further dehydrogenations, which lead to the formation of coke. Here, atomically thin platinum nanolayers on two-dimensional molybdenum titanium carbides are reported as a superior catalyst for this reaction owing to reduced coke formation.

Synthesis and implementation of highly active, stable, and affordable electrocatalysts for the oxygen evolution reaction (OER) is a major challenge in developing energy efficient and economically viable energy conversion devices such as electrolyzers, rechargeable metal-air batteries, and regenerative fuel cells. The current benchmark electrocatalyst for OER is based on iridium oxide (IrOx) due to its superior performance and excellent stability. However, large scale applications using IrOx are impractical due to its low abundance and high cost. Herein, we report a highly active hafnium-modified iridium oxide (IrHfxOy) electrocatalyst for OER. The IrHfxOy electrocatalyst demonstrated ten times higher activity in alkaline conditions (pH = 11) and four times higher activity in acid conditions (pH = 1) than a IrOx electrocatalyst. The highest intrinsic mass activity of the IrHfxOy catalyst in acid conditions was calculated as 6950 A gIrOx-1 at an overpotential (η) of 0.3 V. Combined studies utilizing operando surface enhanced Raman spectroscopy (SERS) and DFT calculations revealed that the active sites for OER are the Ir-O species for both IrOx and IrHfxOy catalysts. The presence of Hf sites leads to more negative charge states on nearby O sites, shortening of the bond lengths of Ir-O, and lowers free energies for OER intermediates that accelerate the OER process.

Upon reduction at 975 °C, a strong metal-support interaction (SMSI) of CeO2 on Pt NPs leads to low rates for ethylene hydrogenation and propane dehydrogenation, but high olefin selectivity for the latter reaction. By contrast, reduction at 550 °C of Pt/CeO2, leads to 5 nm Pt NP’s with ethylene hydrogenation and propane dehydrogenation TORs and low olefin selectivity similar to Pt/SiO2. X-ray absorption fine structure (EXAFS) and scanning transmission electron microscopy (STEM) shows formation of ∼15 nm monometallic Pt nanoparticles partially covered by SMSI CeO2. The propylene selectivity of Pt NP’s covered by SMSI CeO2 was ∼95 % suggesting there were few Pt ensembles capable of catalysing propane hydrogenolysis; while the remaining exposed Pt remain active for dehydrogenation reactions.

Electrochemical CO

Industrial low-temperature methane combustion catalyst Pd/Al2O3 suffers from H2O-induced deactivation. It is imperative to design Pd catalysts free from this deactivation and with high atomic efficiency. Using a small-pore zeolite SSZ-13 as support, herein we report well-defined Pd catalysts with dominant active species as finely dispersed Pd cations, uniform PdO particles embedded inside the zeolite framework, or PdO particles decorating the zeolite external surface. Through detailed reaction kinetics and spectroscopic and microscopic studies, we show that finely dispersed sites are much less active than PdO nanoparticles. We further demonstrate that H2O-induced deactivation can be readily circumvented by using zeolite supports with high Si/Al ratios. Finally, we provide a few rational catalyst design suggestions for methane oxidation based on the new knowledge learned in this study.

In this paper, MCM-41 was synthesized by a soft template technique and MCM-41 supported CuO-CeO2 nano-sized catalysts with different Cu/Ce molar ratios were prepared by a deposition-precipitation method. N2 adsorption, HRTEM-EDS, H2-TPR, XPS characterization, as well as catalytic activity and durability tests for the catalytic combustion of chlorobenzene (CB) were conducted to explore the relationship between the structure and catalytic performance of the catalysts. It is revealed that CuCe(6:1)/MCM-41 has the highest activity and can completely catalyze the degradation of CB at 260 °C. The reasons for the high activity of the catalysts are as follows: MCM-41, a type of mesoporous material which has large pore size and large specific surface area, is suitable as a catalyst carrier. The average diameter of nano-sized CuO and CeO2 particles is about 3–5 nm and adding CeO2 improves the dispersion of active component CuO, which are highly and evenly dispersed on the surface of MCM-41. Characterization results also explain why MCM-41 supported CuO-CeO2 with appropriate proportion can highly enhance the catalytic activity. The reason is that CeO2 acting as an oxygen-rich material can improve the mobility of oxygen species through continuous redox between Ce4+ and Ce3+, and improve the catalytic performance of CuO for CB combustion. Besides, CuCe (6:1)/MCM-41 also displays good durability for CB combustion, both in the humid condition and in the presence of benzene, making it a promising catalytic material for the elimination of chlorinated VOCs.

Reported herein is a unified strategy to generate difluoroalkyl radicals from readily prepared α-difluorinated gem-diols by single electron oxidation. Under microwave irradiation, a catalytic amoun...

In this work, we report a robust Ru phosphide catalyst (RuP), which exhibits high propylene selectivity for propane dehydrogenation, while mono-metallic Ru NPs result in cracking. XPS, synchrotron ...

An Ugi, novel pseudo-Knoevenagel, ring expansion cascade reaction was discovered and utilized for the synthesis of aziridinyl succinimides in one-pot. Subsequently, densely functionalized aziridines and maleimides have been designed and synthesized through similar cascade reactions. The target compounds were prepared by means of a mild reaction and a simple operation procedure, which could be applicable to a broad scope of starting materials. This series of novel cascade reactions generates opportunities for the tailored synthesis of a wide range of biologically active scaffolds through tuneable Ugi inputs. Discovery of compound 8i with comparable potency to sorafenib in liver cancer cell lines could provide a new avenue for liver cancer drug discovery.

A novel photoredox-catalyzed radical addition of methylene-2-oxazolines has been developed under visible light irradiation to synthesize monofluorooxazoles with a quaternary carbon center using 2-bromo-2-fluoro-3-oxo-3-phenylpropionates as radical source. This method with a simple protocol, scalability and high yield offers a facile path to get diverse monofluorinated oxazoles with quaternary C-F centers, which are a class of highly valuable motifs and synthons.

A green 1,4-addition isocyanide-based three-component reaction was developed to synthesize chromanones via a facile, mild, and efficient one-pot protocol without a metal catalyst. The 1,4-addition of isocyanides occurred at the C-2 position of chromones instead of the Schiff base in neat water. We found that the hydrogen bond can dictate the stereo-outcome of olefins, providing an effective method for the diastereomer-selective synthesis of this type of chromanone. The novel green synthetic protocol allowed the quick synthesis of complex chromanones in an environmentally friendly manner.

Cascade reactions that produce multiple chemical bonds in one synthetic operation are important in the efficient construction of complex molecules., Cascade reactions that produce multiple chemical bonds in one synthetic operation are important in the efficient construction of complex molecules. In addition, photoredox and nickel dual catalysis opens a new and powerful avenue for transition-metal-catalyzed cross-coupling reactions. By combining these two concepts, photoredox and nickel dual-catalyzed cascade reactions have been recently established, and they provide an efficient and mild method for accessing a series of valuable organic compounds.

In this study, we show how strong metal–support interaction (SMSI) oxides in Pt–Nb/SiO2 and Pt–Ti/SiO2 affect the electronic, geometric and catalytic properties for propane dehydrogenation. Transmission electron microscopy (TEM), CO chemisorption, and decrease in the catalytic rates per gram Pt confirm that the Pt nanoparticles were partially covered by the SMSI oxides. X-ray absorption near edge structure (XANES), in situ X-ray photoelectron spectroscopy (XPS), and resonant inelastic X-ray scattering (RIXS) showed little change in the energy of Pt valence orbitals upon interaction with SMSI oxides. The catalytic activity per mol of Pt for ethylene hydrogenation and propane dehydrogenation was lower due to fewer exposed Pt sites, while turnover rates were similar. The SMSI oxides, however, significantly increase the propylene selectivity for the latter reaction compared to Pt/SiO2. In the SMSI catalysts, the higher olefin selectivity is suggested to be due to the smaller exposed Pt ensemble sites, which result in suppression of the alkane hydrogenolysis reaction; while the exposed atoms remain active for dehydrogenation.

Electrochemical tip-enhanced Raman spectroscopy (EC-TERS) has been implemented to investigate the structure and activity of iron(II) phthalocyanine (FePc)-a model catalyst for the oxygen reduction reaction (ORR). Using EC-TERS, both reversible change and irreversible degradation to FePc have been observed during ORR. The reversible change in the Raman spectrum of FePc can be related to the FePc molecules that adapt a nonplanar geometry during catalysis. In contrast, the irreversible degradation of FePc is a consequence of FePc demetalation, leading to the subsequent formation of free base phthalocyanine. This observation affirms that FePc demetalation during ORR proceeds via a direct loss of Fe

In this work, functionalized alkyl imidazolium hexafluorophosphate ILs were synthesized and characterized; then, they were applied in the conversion of xylose to furfural under the microwave method. The results showed that when CnMF was used as a catalyst, an acidic environment was provided to promote the formation of furfural. In addition, the heating method, the solvent, and the different structures of cations in the ionic liquid influenced their catalytic activity. In an aqueous solution, the yield of furfural obtained using the microwave method was better than that of the conventional heating method, and the catalytic activity of diimidazole hexafluorophosphate was better than that of monoimidazole. Meanwhile, for the diimidazole hexafluorophosphate, the change of the carbon chain length between the imidazole rings also slightly influenced the yield. Finally, the optimal yield of 49.76% was obtained at 205°C for 8 min using 3,3′-methylenebis(1-methyl-1H-imidazol-3-ium), C1MF, as a catalyst. Mechanistic studies suggested that the catalytic activity of C1MF was mainly due to the combined effect of POFn (OH)3-n and imidazole ring. Without a doubt, the catalytic activity of C1MF was still available after five cycles, which not only showed its excellent catalytic activity in catalyzing the xylose to prepare the biomass platform compound furfural but also could promote the application of functionalized ionic liquids.

In this study, the vanadium pentoxide (V2O5), functionalized carbon nanotubes (f-CNT), and polypyrrole (PPy) based composites films have been prepared through a facile synthesis method and their electrochemical performance were evaluated as freestanding negative electrodes of supercapacitor. A hydrous V2O5 gel prepared by treating V2O5 powder with H2O2 was mixed with f-CNT to obtain V2O5/f-CNT composite film. V2O5/f-CNT composite was then coated with PPy through vapor phase polymerization method. The PPy deposited on the V2O5/f-CNT prevented the dissolution of V2O5 and thus resulted in an improved the capacitance and cycle life stability for V2O5/f-CNT/PPy composite electrode. V2O5/f-CNT/PPy freestanding negative electrode exhibited a high areal capacitance value (1266 mF cm−2 at a current density of 1 mA cm−2) and good cycling stability (83.0% capacitance retention after 10,000 charge-discharge cycles). The superior performance of the V2O5/f-CNT/PPy composite electrode can be attributed to the synergy between f-CNT with high conductivity and V2O5 and PPy with high-energy densities. Thus, V2O5/f-CNT/PPy composite based electrode can effectively mitigate the drawbacks of the low specific capacitance of CNTs and the poor cycling life of V2O5.

The genotype and phenotype of acral melanoma are obviously different from UV-radiation-induced melanoma. Based on the clinical data, mechanical stimulation is believed to be a potential cause of acral melanoma. In this case, it is desirable to clarify the role of mechanical stimulation in the progression of acral melanoma. However, the pathological process of cyclic straining that stimulates acral melanoma is still unclear. In this study, the influence of cyclic straining on melanoma cell proliferation was analyzed by using a specifically designed cell culture system. In the results, cyclic straining could promote melanoma cell proliferation but was inefficient after the disruption of cytoskeleton organization. Therefore, the mechanotransduction mechanism of promoted proliferation was explored. Both myosin and actin polymerization were demonstrated to be related to cyclic straining and further influenced the morphogenesis of melanoma cells. Additionally, the activation of mechanosensing transcription factor YAP was related to regulatory morphogenesis. Furthermore, expression levels of melanoma-involved genes were regulated by cyclic straining and, finally, accelerated DNA synthesis. The results of this study will provide supplementary information for the understanding of acral melanoma.

Single-atom catalysts (SACs) have aroused great attention due to their high atom efficiency and unprecedented catalytic properties. A remaining challenge is to anchor the single atoms individually on support materials via strong interactions. Herein, single atom Co sites have been developed on functionalized graphene by taking advantage of the strong interaction between Co2+ ions and the nitrile group of cyanographene. The potential of the material, which is named G(CN)Co, as a SAC is demonstrated using the electrocatalytic hydrazine oxidation reaction (HzOR). The material exhibits excellent catalytic activity for HzOR, driving the reaction with low overpotential and high current density while remaining stable during long reaction times. Thus, this material can be a promising alternative to conventional noble metal-based catalysts that are currently widely used in HzOR-based fuel cells. Density functional theory calculations of the reaction mechanism over the material reveal that the Co(II) sites on G(CN)Co can efficiently interact with hydrazine molecules and promote the NH bond-dissociation steps involved in the HzOR.

The charge transport in single-molecule junctions depends critically on the chemical identity of the anchor groups that are used to connect the molecular wires to the electrodes. In this research, we report a new anchoring strategy, called the electrostatic anchor, formed through the efficient Coulombic interaction between the gold electrodes and the positively charged pyridinium terminal groups. Our results show that these pyridinium groups serve as efficient electrostatic anchors forming robust gold-molecule-gold junctions. We have also observed binary switching in dicationic viologen molecular junctions, demonstrating an electron injection-induced redox switching in single-molecule junctions. We attribute the difference in low- and high-conductance states to a dicationic ground state and a radical cationic metastable state, respectively. Overall, this anchoring strategy and redox-switching mechanism could constitute the basis for a new class of redox-activated single-molecule switches.

Development of earth-abundant electrocatalysts for hydrogen evolution and oxidation reactions in strong acids represents a great challenge for developing high efficiency, durable, and cost effective electrolyzers and fuel cells. We report herein that hafnium oxyhydroxide with incorporated nitrogen by treatment using an atmospheric nitrogen plasma demonstrates high catalytic activity and stability for both hydrogen evolution and oxidation reactions in strong acidic media using earth-abundant materials. The observed properties are especially important for unitized regenerative fuel cells using polymer electrolyte membranes. Our results indicate that nitrogen-modified hafnium oxyhydroxide could be a true alternative for platinum as an active and stable electrocatalyst, and furthermore that nitrogen plasma treatment may be useful in activating other non-conductive materials to form new active electrocatalysts., Renewable hydrogen technologies are promising for alternative energy, but are encumbered by the kinetics of electrochemical reactions in harsh conditions. Here, authors report nitrogen-modified hafnium oxyhydroxide for electrocatalysis of hydrogen evolution and oxidation reactions in acidic media.

Recently, stable non-oxidative conversion of methane (NOCM) for up to 8 h with a C2 selectivity greater than 90% has been reported over Pt–Bi/ZSM-5 at moderate temperatures (600–700 °C). In this study, we show that the structure of the bimetallic nanoparticles on Pt–Bi/ZSM-5 catalyst is similar to Pt–Bi/SiO2. EXAFS indicates the formation of Pt-rich bimetallic Pt–Bi nanoparticles with Pt–Bi bond distance of 2.80 A. The XRD spectra (on SiO2) are consistent with cubic, intermetallic surface Pt3Bi phase on a Pt core. The Pt3Bi structure is not known in the thermodynamic phase diagram. In all catalysts, only a small fraction of Bi alloys with Pt. At high Bi loadings, excess Bi reduces at high temperature, covering the catalytic surface leading to a loss in activity. At lower Bi loadings with little excess Bi, the Pt3Bi surface is effective for non-oxidative coupling of CH4 (on ZSM-5) and propane dehydrogenation (on SiO2).

In this investigation, a mesoporous γ-Al2O3 with large surface area and good thermal stability was synthesized and employed as the support for preparing a series of Pd-Pt nanocrystalline catalysts by using a high-temperature solution-phase reduction method. The PdOx (x = 0, 1) and PtOx (x = 0, 2) nanoparticles were found to have a small diameter (about 2 nm) and were highly dispersed on the surface of the mesoporous γ-Al2O3. The results show that catalysts with the appropriate ceria greatly improved the physical adsorption/chemisorption of benzene to Pd-Pt nanocrystals, which greatly enhanced the activity to achieve the complete oxidation of benzene. The high activity of the catalyst was mainly due to the nano-effects of Pd-Pt nanocrystals and the interactions among the active components. 0.2%Pd-Pt(1:1)/10%Ce/γ-Al2O3 demonstrated the best activity for the complete oxidation of benzene at 200 °C. Furthermore, this catalyst maintained 95% benzene conversion for 1000 h at 190 °C and displayed good resistance to water and Cl-poisoning, which indicated that the Pd-Pt nanocrystalline catalysts have promise for adoption by the industry.

Tailoring the structure of metal components and interaction with their anchored substrates is essential for improving the catalytic performance of supported metal catalysts; the ideal catalytic configuration, especially down to the range of atomic layers, clusters, and even single atoms, remains a subject under intensive study. Here, an Ir-on-MXene (Mo

Mesoporous silica-pillared clay (SPC) was synthesized by a soft template method. Compared with the raw montmorillonite (MMT), the basal spacing of SPC increased from 0.96 to 2.61 nm, the specific surface area increased from 30 to 453 m2/g, and the thermal stability was also improved, all of which could reduce the mass transfer resistance and improve the adsorption capacity of toluene. SPC supported Co3O4 and rare earth (Y, La, Ce, Pr and Nd) nano-composite catalysts were prepared by a deposition-precipitation method. Among them, 10% Co-5% Ce/SPC displayed the highest catalytic combustion activity, and the reaction temperature for toluene combustion was about 200 °C (98% conversion). This catalyst displayed good durability, and conversion of toluene dropped slightly from 96% to 90% in 1000 h continuous reaction at 190 °C. Co3O4 and CeO2 had particle sizes of 5–8 nm and were dispersed homogeneously on the surface of SPC. Introduction of CeO2 enhanced oxygen storage/transport capacity, and improved the dispersion of Co3O4 on SPC. The interaction of Co3O4-CeO2 and SPC, the co-existence of Co2+/Co3+ and the higher concentration of Ce3+ ions on the catalyst surface contribute to the high catalytic oxidative activity of 10% Co-5% Ce/SPC for toluene combustion.

In the study, the effects of synthesis conditions for AlNi composite pillaring agents (Al/Ni molar ratio, aging temperature and aging time) on the structure and stability of AlNi pillared clays (AlNi-PILC) were investigated. And the results showed that the above synthesis factors could control and adjust the specific surface area, pore volume and basal spacing of AlNi-PILC. The formation of spinal NiAl2O4 markedly improved the thermal stability and anti-sintering properties of AlNi-PILC and maintain a stable mesoporous structure. Pd/AlNi-PILC nanocrystalline catalyst obtained by using a high-temperature solution-phase reduction method presented a strong interaction between the active species PdOx (x = 0, 1) and AlNi-PILC. The PdOx nanocrystals had excellent stability with a small diameter (1–2 nm) and the nanocrystals were evenly mono dispersed on the surface of AlNi-PILC. Thus, 0.2%Pd/AlNi-PILC exhibited excellent catalytic oxidation properties and completed catalytically oxidize low concentrations of benzene at 250 °C. Furthermore, 0.2%Pd/AlNi-PILC maintained 90% benzene conversion at 240 °C after a continuous reaction for 1000 h in dry air. And in either wet conditions or in the chlorine-containing VOCs, 0.2%Pd/AlNi-PILC maintained high catalytic activity and thus showed potential in industrial applications.

The mechanism and charge effect of cycloisomerization of ω-alkynylfuran (Hashmi phenol synthesis) catalyzed by single-walled helical gold nanotubes (Au SWNTs) have been systematically investigated via density functional theory. Cycloisomerization of ω-alkynylfuran occurs by the 5-exo Friedel–Crafts-type (FCT) mechanism, namely 5-exo cyclization, furan ring opening, and ring closing of the dienone carbene–gold intermediate. The reactions with Au(6,0), Au(6,1), Au(6,2) and Au(6,3) SWNTs show low energy barriers along the 5-exo FCT path in acetonitrile solvent, but have different the rate-determining steps. From an energy perspective, the reaction rate-determining step catalyzed by Au(6,0) and Au(6,3) is the ring-closing of dienone carbine-gold intermediate, but that of Au(6,1) and Au(6,2) is the IM5 dissociation from the Au SWNTs, which can be attributed to the diversity of the d-band centers of the Au(6,m) SWNTs. The effect of the charge of the Au SWNTs on the catalytic activity was also investigated. Theoretical analysis shows a prominent charge effect, where the cationic Au(6,0), Au(6,3) SWNTs and anionic Au(6,1), Au(6,2) SWNTs are more favorable for the Hashmi phenol synthesis reaction. This results can be attributed to the Au(6,0) and Au(6,3) SWNTs with positive charge can reduce the adsorption energy of the substrate on the catalyst surface and decrease the energy barrier of the cyclization process and ring-closing step. Besides, the Au(6,1) and Au(6,2) with an anion could obviously decrease the dissociation energy of IM5 which is help for the Hashmi phenol reaction. Theoretical analysis shows that the structure and charge effects could influence the catalytic activity of Au(6,m) SWNTs toward Hashmi phenol synthesis. This work will provide insight into cycloisomerization of ω-alkynylfuran and valuable information for application of Au SWNTs in catalysis.

Understanding the mechanism of the catalytic reaction is an effective way to design new high-performance catalysts. The mechanisms of alkyne/olefin hydrogenations catalyzed by a nonclassical Co–N2 ...

Understanding the mechanism of a catalytic reaction is of fundamental importance not only scientifically but also technologically to the design of high-performance catalysts. In this work, the mechanisms of 1-phenyl-1-propyne and cis-β-methylstyrene hydrogenations catalyzed by Cu55 and ligand-coated Cu55 are explored in detail by means of density functional theory (DFT). The calculated results indicate that the semihydrogenation selectivity of the catalyst can be effectively controlled by employing a suitable ligand. That is, the PCy3 and PPh3 ligands used to coat Cu55 can largely raise the energy barrier of the rate-determining step for cis-β-methylstyrene hydrogenation. By the study of energy decomposition analysis (EDA) and charge density difference, it can be found that the deformation energies of the substrate fragments play a crucial role in the energy barriers of the rate-determining steps. The large hindrance effect of the ligands is beneficial for improving the semihydrogenation selectivity of the catalysts. This study provides significant information for future catalyst design and on the physical origin of the phosphine ligand-coated nanoparticle catalysis for semihydrogenation.

Unveiling the reaction mechanism is significant for developing high-performance catalysts. In this paper, a series of precisely controlled PdxM147-x (M = Cu, Pt, Au, Rh, Ru) dendrimer encapsulated nanoparticles (DENs) has been successfully synthesized. The mechanisms of PdxM147-x as catalysts for Suzuki cross-coupling reactions were investigated by combining experimental and theoretical methods. The experimental results indicate that Pd74Cu73 DEN shows similar activity to Pd147 DEN and excellent substrate adaptability under mild reaction conditions. Moreover, the Cu component can play an important role in tuning the catalytic activity of PdxCu147-x DEN. Density functional theory (DFT) calculations illustrate that the similar activities of the Pd147 and Pd74Cu73 DENs originate from the comparable energy barriers of the rate-determining steps. The partial density of states (PDOS) and electron density differences demonstrate that Cu decreases the intensities of the valence orbitals of the top and edge Pd atoms and weakens orbital interactions between the intermediates and Pd74Cu73 DEN, leading to low desorption energies of the products. This work can provide a promising strategy to reduce the cost of Pd catalysts in Suzuki cross-coupling reactions.

An Ugi, novel pseudo-Knoevenagel, ring expansion cascade reaction was discovered and utilized for the synthesis of aziridinyl succinimides in one-pot. Subsequently, densely functionalized aziridines and maleimides have been designed and synthesized through similar cascade reactions. The target compounds were prepared by means of a mild reaction and a simple operation procedure, which could be applicable to a broad scope of starting materials. This series of novel cascade reactions generates opportunities for the tailored synthesis of a wide range of biologically active scaffolds through tuneable Ugi inputs. Discovery of compound 8i with comparable potency to sorafenib in liver cancer cell lines could provide a new avenue for liver cancer drug discovery.

A post-Ugi diastereoselective one-pot cascade reaction requiring no metal catalyst was developed. The reaction scope was wide with mild conditions and good yields. A collection of spiroindolines was prepared by the protocol and screening tests in several difficult-to-inhibit cancer cell lines were conducted. The relationship of structure and anticancer activities was promising and in the Huh7 cell lines compound 16 j is more potent than Vinbalstine. The cyclization design strategy could be applicable to other multicomponent reactions (MCRs) for synthesizing bioactive and drug-like heterocycles.

Unveiling the acetylene adsorption is crucial for designing novel and highly active catalyst for the semihydrogenation of alkyne. In order to achieve this goal, we have studied C 2 H 2 adsorption on the various nanoporous gold models in detail, including the Au(100), Au(111) and Au(321) slab models. The calculated results indicate that the C atoms of C 2 H 2 experience rehybridization from sp toward sp 2 /sp 3 when the adsorption occurs on bridge and hollow sites, which can be illustrated via the projected density of state (PDOS) and crystal orbital Hamilton population (COHP). Meanwhile, the formation of σ(Au C) bond is beneficial for facilitating acetylene adsorption and the kink Au atom plays an important role for the C 2 H 2 adsorption. In addition, for C 2 H 2 adsorption on the Ag doped nanoporous gold, the configurations strongly depend on the position of superficial unsubstituted Au atoms. Further, the inversely relationship has been found between the adsorption energies and number of the Ag substituents, demonstrating that the superficial Ag substituents are harmful for C 2 H 2 adsorption and activation.

Operando Raman spectroscopy and electrochemical techniques were used during the oxygen evolution reaction to identify the composition and local structure of electrodeposited CoOxHy and NiCoOxHy catalyst films. Before evaluation, the electrodeposited samples were subjected to a variety of thermal and electrochemical conditioning procedures, which generated unique initial catalyst structures and crystallinities. During oxygen evolution, Ni-modified CoOxHy films having lower initial crystallinity underwent substantial structural evolution that began with an irreversible transformation of a spinel local structure to an amorphous CoO structure at low anodic potentials (0.2 V vs Ag/AgCl). Increasing anodic polarization to greater than 0.3 V vs Ag/AgCl facilitated additional structural conversion from the amorphous CoO structure to a complex phase best described as an amalgamation of NiOOH and layered CoO2 motifs (NiOOH-h-CoO2) under elevated oxygen evolution rates. The formation of this NiOOH-h-CoO2 active stru...

Herein, a novel self-assembled nanoprobe for the long-term tracking of the nucleoli of cancer cells and for differentiating between clinical breast cancer tissues and para-carcinoma tissues has been developed.

In the present article, the mechanism of 1,6-enyne cycloisomerization catalyzed by the planar Au 8 cluster was investigated in details by means of density functional theory. The effects of the size and shape of the gold nanoclusters (Au 7-20 ) on their catalysis of 1,6-enyne cycloisomerization were also studied. The computational results indicate that the main reaction channels of the 1,6-enyne cycloisomerization on the Au 8 cluster are the 5–exo–anti–cycloisomerization, and the single cleavage pathway is slightly more feasible than the double cleavage pathway. The selectivity of 1,6-enyne cycloisomerization catalyzed by the gold clusters is controlled by the orbital interaction between the gold atoms and the carbene fragment in the migration of CH 2 group. In addition, the influence of coordinate environment of the gold atoms on adsorption energy, catalytic activity, and regio-selectivity were amply interpreted as well.

With increasing concerns for global warming, the solar-driven photocatalytic reduction of CO2 into chemical fuels like methanol is a propitious route to enrich energy supplies, with concomitant reduction of the abundant CO2 stockpiles. Herein, a novel single atom-confinement and a strategy are reported toward single ruthenium atoms dispersion over porous carbon nitride surface. Ruthenium single atom character is well confirmed by EXAFS absorption spectrometric analysis unveiling the cationic coordination environment for the single-atomic-site ruthenium center, that is formed by Ru-N/C intercalation in the first coordination shell, attaining synergism in N-Ru-N connection and interfacial carrier transfer. From time resolved fluorescence decay spectra, the average carrier lifetime of the RuSA-mC3 N4 system is found to be higher compared to m-C3 N4 ; the fact uncovering the crucial role of single Ru atoms in promoting photocatalytic reaction system. A high yield of methanol (1500 µmol g-1 cat. after 6 h of the reaction) using water as an electron donor and the reusability of the developed catalyst without any significant change in the efficiency represent the superior aspects for its potential application in real industrial technologies.

It is observed that pyridinium is hydrogenated at Pt electrodes in electrochemical conditions consistent with those previously shown to yield selective reduction of carbon dioxide to methanol and formic acid. The hydrogenation proceeds through a heterogeneous reaction with chemisorbed hydrogen, which originates from one-electron surface proton transfer reactions. Electrochemical methods are used to show that pyridinium adsorbs on the Pt surface, consistent with the proposed heterogeneous reaction mechanism. From this first observation of the electrochemical generation of a stable hydrogenated piperidinium-like near-surface species it logically follows that dihydropyridinium, the protonated form of the previously-proposed hydride-shuttling reduction catalyst, must transiently exist under these conditions near the Pt surface in the presence of carbon dioxide. Therefore partially hydrogenated heterocycles remain strong candidates for catalytically active species that enable selective carbon dioxide reduction. More generally, the observed mild potentials required for electrocatalytic hydrogenation of stable organics implies that engineered transfer hydrogenations involving organic adsorbates can be a viable approach for achieving selective carbon dioxide reduction to fuels.

Understanding the role of CeO2(111) supports is meaningful for designing high-performance metal oxide-supported gold nanoparticle catalysts. Here, density functional theory calculations were employed to study ω-alkynylfuran cycloisomerisation on CeO2(111)-supported Au clusters. The various reactive sites, including the atop, interface and edge sites, and the role of oxygen vacancies on the defective CeO2(111) surface were taken into account. On the basis of the computed results and energetic analysis, it was found that the atop and interface sites show high catalytic activity toward ω-alkynylfuran cycloisomerisation, and the edge site of Au10/CeO2(111)-s (stoichiometric) exhibits similar catalytic activity. Meanwhile, the surface oxygen vacancies of CeO2(111) can cause some negative and positive effects on the adsorption energy and the catalytic activity. Furthermore, to shed light on the role of the CeO2(111) support, an analysis of ω-alkynylfuran cycloisomerisation catalyzed by Au3–4/CeO2(111) and free Au3–4 clusters was performed as well. Our results indicate that the presence of the CeO2(111) support can not only change the orbital levels of the gold clusters, but also cause charge recombination and decrease the positive charge on the Au (top) atom. These virtues can effectively lead to a decrease in the adsorption energy, facilitating electrophilic attack of the C atom on the furan ring.