Shuang-Feng Yin

Facile regio- and stereoselective hydrometalation of alkynes with a combination of carboxylic acids and group 10 transition metal complexes: selective hydrogenation of alkynes with formic acid.

A facile, highly stereo- and regioselective hydrometalation of alkynes generating alkenylmetal complex is disclosed for the first time from a reaction of alkyne, carboxylic acid, and a zerovalent group 10 transition metal complex M(PEt(3))(4) (M = Ni, Pd, Pt). A mechanistic study showed that the hydrometalation does not proceed via the reaction of alkyne with a hydridometal generated by the protonation of a carboxylic acid with Pt(PEt(3))(4), but proceeds via a reaction of an alkyne coordinate metal complex with the acid. This finding clarifies the long proposed reaction mechanism that operates via the generation of an alkenylpalladium intermediate and subsequent transformation of this complex in a variety of reactions catalyzed by a combination of Brϕnsted acid and Pd(0) complex. This finding also leads to the disclosure of an unprecedented reduction of alkynes with formic acid that can selectively produce cis-, trans-alkenes and alkanes by slightly tuning the conditions.

Room-Temperature Synthesis of Flower-Like BiOX (X═Cl, Br, I) Hierarchical Structures and Their Visible-Light Photocatalytic Activity

A simple method for facile synthesis of three-dimensional (3D) bismuth oxyhalide (BiOX, X═Cl, Br, I) hierarchical structures at room temperature has been developed. Under the influence of L-lysine surfactant, the bismuth and halogen (Cl, Br, I) sources hydrolyze and self-assemble into flower-like hierarchical architectures within 10 min. The resulted materials were characterized by XRD, FESEM, TEM, UV-vis DRS, and N2 adsorption-desorption techniques. We found that l-lysine is indispensable for their formation and the amount of HX has great effect on the final morphology. The BiOX (X═Cl, Br, I) hierarchical architectures are composed of single-crystalline nanoplates. We propose an amino-and-carboxyl structure-directing mechanism for the formation of the hierarchical structures. To evaluate the photocatalytic activity of the as-prepared materials, rhodamine-B was employed as a probe dye for degradation under visible light. All of the BiOX (X═Cl, Br, I) with 3D architectures show higher photocatalytic activities than their sheet-like counterparts. The superior activity is ascribed to the better light-harvesting capacity of the 3D hierarchical structures. The adopted method can be applied for large-scale generation of novel structures of similar kinds in a facile manner.

CdS Nanowires Decorated with Ultrathin MoS2 Nanosheets as an Efficient Photocatalyst for Hydrogen Evolution.

CdS nanowires decorated with ultrathin MoS2 nanosheets were synthesized for the first time by ultrasonic exfoliation by using dimethylformamide as the dispersing agent. An excellent hydrogen evolution rate of 1914 μmol  h(-1) (20 mg catalyst) under visible-light irradiation (λ ≥ 400 nm, ≈ 154 mW cm(-1) ) and an apparent quantum yield of 46.9% at λ=420 nm were achieved over the MoS2 /CdS composite. The presence of ultrathin MoS2 nanosheets (rich in active edge sites) on the CdS surface promotes the separation of photogenerated charge carriers and facilitates the surface processes of photocatalytic hydrogen evolution.

Nickel-catalyzed direct thiolation of C(sp(3))-H bonds in aliphatic amides.

Nickel-catalyzed thiolation of the inactivated methyl C(sp(3))-H bonds of aliphatic amides with disulfide is described. It is a novel strategy for the synthesis of thioethers with the ultimate goal of generating thioether carboxylic acids with various functional groups.

Copper-Mediated Remote C–H Bond Chalcogenation of Quinolines on the C5 Position

An efficient and convenient method is developed for the remote C-H bond chalcogenation of 8-aminoquinoline scaffolds on the C5 position that is geometrically inaccessible. The protocol makes use of inexpensive CuBr2 as mediator and shows good tolerance toward numerous disulfides/diselenides and aliphatic amides, giving the corresponding products in good to excellent yield.

Copper-Catalyzed Aerobic Oxidative Amination of sp3C–H Bonds: Efficient Synthesis of 2-Hetarylquinazolin-4(3H)-ones

An efficient synthesis of 2-hetarylquinazolin-4(3H)-ones via copper-catalyzed direct aerobic oxidative amination of sp(3)C-H bonds has been developed. This tandem oxidation-amination-cyclization transformation represents a straightforward protocol to prepare 2-hetaryl-substituted quinazolinones from easily available 2-aminobenzamides and (2-azaaryl)methanes.

Synthesis and structure of an air-stable cationic organobismuth complex and its use as a highly efficient catalyst for the direct diastereoselective Mannich reaction in water

An air-stable cationic organobismuth complex was successfully synthesized and found to show high catalytic efficiency in the direct diastereoselective Mannich reaction in water.

Hollow peanut-like m-BiVO4: facile synthesis and solar-light-induced photocatalytic property

Monoclinic bismuth vanadate (m-BiVO4) with novel hollow peanut-like morphology was synthesized for the first time using L-lysine as surfactant. The use of L-lysine and the crystallization procedure is indispensable in getting the peanut-like morphology. The photocatalytic activity of the m-BiVO4 samples under solar-light irradiation was evaluated for degradation of crystal violet and methylene blue. Crystallization and calcination temperature are important factors affecting the photocatalytic activity of m-BiVO4, and best performance was observed over the sample that crystallized at 160 °C in the presence of L-lysine and subsequently subjected to calcination at 550 °C. The as-prepared BiVO4 showed good stability in catalyst recycling. Based on the results of XRD, XPS, FESEM, TEM (HRTEM), UV-vis diffuse reflectance spectroscopy, and N2 adsorption–desorption characterization, the good photocatalytic activity of the m-BiVO4 sample is attributed to its unique hollow peanut-like morphology and pure monoclinic phase of high crystallinity.

Environmentally benign synthesis of branched Bi2O3–Bi2S3 photocatalysts by an etching and re-growth method

Synthesizing heterostructured nanomaterials of controllable morphologies by an environmentally benign method is an area of frontier research. In the present work, Bi2O3 microtubes and branched Bi2O3–Bi2S3 composites were synthesized by a simple hydrothermal method without the need for using toxic substances as surfactants (templates) or solvents. Single-crystalline Bi2S3 nanorods and nanosheets are controllably grown on the surface of Bi2O3 microtubes. We propose an “etching and re-growth” mechanism for the generation of the Bi2O3–Bi2S3 composites. Owing to the presence of Bi2S3 and the branched structure, there is great improvement of visible-light absorption ability, and due to the formation of Bi2O3–Bi2S3 heterojunctions, there is facile separation of photogenerated charge carriers. It is observed that the as-prepared composites show an enhanced photocurrent response and improved photocatalytic activity under visible-light illumination.

Metal- and Oxidant-Free Synthesis of Quinazolinones from β-Ketoesters with o-Aminobenzamides via Phosphorous Acid-Catalyzed Cyclocondensation and Selective C–C Bond Cleavage

A general and efficient phosphorous acid-catalyzed cyclocondensation of β-ketoesters with o-aminobenzamides via selective C-C bond cleavage leading to quinazolinones is developed. This reaction proceeds smoothly under metal- and oxidant-free conditions, giving both 2-alkyl- and 2-aryl-substituted quinazolinones in excellent yields. This strategy can also be applied to the synthesis of other N-heterocycles, such as benzimidazoles and benzothiazoles.