Catalytic transformations involving metal carbenes are considered one of the most important aspects of homogeneous transition metal catalysis. Recently, gold-catalyzed generation of gold carbenes from readily available alkynes represents a significant advance in metal carbene chemistry. This Review summarizes the advances in the gold-catalyzed nitrene-transfer reactions of alkynes with nitrogen-transfer reagents, such as azides, nitrogen ylides, isoxazoles, and anthranils, and gold-catalyzed carbene-transfer reactions, involving oxygen atom-transfer reactions of alkynes with nitro compounds, nitrones, sulfoxides, and pyridine N-oxides, through the presumable α-imino gold carbene and α-oxo gold carbene intermediates, respectively. Gold-catalyzed processes are reviewed by highlighting their product diversity, selectivity, and applicability, and the mechanistic rationale is presented where possible.

The electrochemical reduction of CO2 provides an alternative carbon‐neutral path for renewable synthesis of fuels and value‐added chemicals. This work demonstrates that dendritic, bimetallic Cu–Bi electrocatalysts with nanometer‐sized grains are capable of formate generation with a high selectivity. Optimizing composition of electrocatalyst could achieve a faradic efficiency of 90 % at −0.8 to −0.9 VRHE, and a partial current of more than 2 mA cm−2. The combination of Cu with Bi enables modulation of the adsorption strength of intermediates. This leads to an increased selectivity and suppressed formation of spurious species, especially hydrogen and CO. Comparison of product distribution for Cu–In versus Cu–Bi indicated that Bi is essential to induce a favorable adsorption configuration of the intermediate species and to promote formate production.

Nanostructured titanium dioxide (TiO 2 ) presents considerable potential as a photoanode in low cost, sustainable photoelectrochemical systems for solar water splitting. The wide band gap combined with the presence of trap states and reduced water oxidation kinetics limit, however, the photocurrent performance to only ∼1 mA cm −2 . Increasing the disorder of the crystal structure at the surface, on the other hand, has been proven to increase light absorption via band gap narrowing, and conversion efficiency. In this work, anodized TiO 2 nanotubes have been irradiated with a pulsed UV laser in deionized water environment to introduce lattice disorder. As a result, the photocurrent improved by 1.6-fold under simulated sunlight compared with pristine TiO 2 nanotube arrays at 1.23 V RHE . For all samples the water oxidation reaction kinetics is determined to be the limiting step for the solar-to-current conversion at low bias (0.5−0.7 V RHE ), while modified nanotube arrays display a 78% water oxidation selectivity at 1.23 V RHE , compared to 65% for the pristine TiO 2 nanotubes. The electronic density of states of the modified nanotubes is evaluated using electrochemical impedance spectroscopy, revealing that selective laser irradiation improved the number density of shallow donors while reducing the density of deep trap states.

Described herein is an organocatalytic enantioselective desymmetrizing cycloisomerization of arylsulfonyl‐protected ynamide cyclohexanones, representing the first metal‐free asymmetric Conia‐ene‐type carbocyclization. This method allows the highly efficient and atom‐economical construction of a range of valuable morphans with wide substrate scope and excellent enantioselectivity (up to 97 % ee). In addition, such a cycloisomerization of alkylsulfonyl‐protected ynamide cyclohexanones can lead to the divergent synthesis of normorphans as the main products with high enantioselectivity (up to 90 % ee). Moreover, theoretical calculations are employed to elucidate the origins of regioselectivity and enantioselectivity.

A selective and high sensitive SERS substrate based on MoO3 nanorod was fabricated through the finely controllable coating of an ultrathin molecule-imprinting polymethacrylic acid layer.

Bi2Se3 was synthesized by a room-temperature deposition technique and successive ionic layer adsorption and reaction (SILAR) method with the aim to understand the formation, crystallinity, optical properties, and energy band structure of this material. The Bi2Se3 morphology was found to change from nanoparticles to that of a nanocluster network by increasing the SILAR deposition cycles. The crystalline structure of as-prepared Bi2Se3 determined from the grazing-incidence X-ray diffraction (GI-XRD) pattern was found to have a mixed of metastable orthorhombic and rhombohedral phases which was further confirmed from our analysis of the Raman spectra. The optical bandgap of Bi2Se3 varied from 1.58 to 1.05 eV for 15–90 cycles of deposition, in contrast to the semimetallic 0.3 eV bandgap exhibited by the pure rhombohedral phase. A schematic band diagram of Bi2Se3 prepared by 45 SILAR cycles was constructed for the mixed-phase Bi2Se3. The flat-band potential was determined to be at 0.46 V vs. RHE from Mott–Schottky analysis. Low-temperature annealing at 100 °C for 1 h resulted in the improvement of the rhombohedral phase fraction which was confirmed from analysis of GI-XRD pattern and pronounced E2 g and A2 1g bulk vibrational modes in the Raman spectrum. The absorption cutoff after annealing was found to be red-shifted combined with a sub-bandgap absorption above 0.78 eV. The post-annealing results indicated the onset of an early stage transition from semiconductor to semi-metallic properties for Bi2Se3.

In this study, we selected basalt fiber (BF) as a functional filler to improve the mechanical properties of ethylene vinyl acetate (EVA)-based flame retardant materials. Firstly, BF was modified by grafting γ-aminopropyl triethoxysilane (KH550). Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS) were used to comprehensively prove the successful modification of the BF surface. Subsequently, the modified BF was introduced into the EVA/magnesium hydroxide (MH) composites by melt blending. The limiting oxygen index (LOI), UL-94, cone calorimeter test, tensile test, and non-notched impact test were utilized to characterize both the flame retardant properties and mechanical properties of the EVA/MH composites. It was found that the mechanical properties were significantly enhanced without reducing the flame retardant properties of the EVA/MH composites. Notably, the surface treatment with silane is a simple and low-cost method for BF surface modification and the pathway designed in this study can be both practical and effective for polymer performance enhancement.

Direct functionalization of inert C(sp3 )-H bonds is a topic of immense contemporary interest and exceptional value in organic synthesis. The recent research has established a novel and practical protocol which features the engagement of vinyl cation species to functionalize C(sp 3 )-H bonds. The discussion of the topic is arranged by the strategies to generate the reactive intermediates, including ionization of vinyl triflates, addition of electrophiles to alkynes, tandem cyclization of enynes or diynes, and decomposition of β-hydroxy-α-diazo ketones. This review closes with a personal perspective on the dynamic research area of unactivated C(sp 3 )-H functionalization via vinyl cations. Hopefully, it will provide timely illumination and beneficial guidance for organic chemists who are interested in this area. Meanwhile continued development of the field is strongly anticipated in the future.