NaBH4-Reduction Induced Tunable Oxygen Vacancies in LaNiO2.7 to Enhance the Oxygen Evolution Reaction

The tunable oxygen vacancies of LaNiO3 (LNO-Vo) is realized by the theoretical prediction and NaBH4-reduction approach. The LNO2.7 catalyst exhibits superior catalytic activity and long-time stability for water oxidation. A...

Synthesis, Characterization and Antimicrobial Activities of 1-((5-Bromobenzofuran-2yl)methyl)-4-substituted phenyl-1H-1,2,3-triazoles

A synthesis of useful intermediate, 2-(azidomethyl)-5-bromobenzofuran starting from 5-bromobenzofuran-2-carboxylic acid is described. The reaction of 5-bromo-2-(iodomethyl)benzofuran with sodium azide affords 2-(azidomethyl)-5-bromobenzofuran. 5-Bromo-2-(iodomethyl)benzofuran was obtained from a combination of consecutive 5-bromobenzofuran-2-carboxylic acid reactions involving NaBH4 reduction followed by the iodination of the resulting alcohol. The utility of 2-(azidomethyl)-5-bromobenzofuran has been demonstrated for the preparation of a novel series of 1-((5-bromobenzofuran-2-yl-)methyl)-4-substituted phenyl-1H-1,2,3-triazoles in excellent yields. The newly synthesized compounds have been characterized and evaluated for antimicrobial activities against Gram-negative and Gram-positive bacterial strains.

Synthesis of Optically Active Hydroxyalkyl Cycloheptatrienes: A Key Step in the Total Synthesis of 6,11-Methylene-LXB4

Starting from methyl cycloheptatrienyl-1-carboxylate, 6-acylation was successfully achieved employing glutaryl chloride in the presence of AlCl3 under controlled reaction conditions to furnish keto carboxylic acid product. After protection of this keto carboxylic acid as tert-butyl ester, reagent-controlled enantioselective reductions delivered configuration-defined methyl-6-hydroxylalkyl cycloheptatriene-1-carboxylates with up to 80% ee. Whereas simple NaBH4 reduction of the keto carboxylic acid and subsequent lactonization afforded a methyl-6-tetrahydropyranonyl cycloheptatriene-1-carboxylate. Resolution using chiral HPLC delivered the product enantiomers with up to >99% ee Finally, ECD analyses enabled structure elucidation. The products are used as key intermediates in enantioselective 6,11-methylene-lipoxin B4 syntheses.

Large-Scale Synthesis of 2-Chlorotetrahydroquinoline and 2-Chlorotetrahydroquinolin-8-one

An efficient large-scale preparation of 2-chlorotetrahydroquinoline with cyclohexanone and benzylamine as starting materials was developed and well optimized, in which benzyl-protected enamide was successfully cyclized and benzyl group was directly removed under Vilsmeier conditions. Azeotropic distillation provided 264 g of 2-chlorotetrahydroquinoline (79%) on a 2 mol scale of reaction without intermediate isolation. The downstream product 2-chlorotetrahydroquinolin-8-one was acquired through Boekelheide rearrangement, hydrolysis of acetate via NaBH4 reduction, and Anelli oxidation. With the developed procedure, the intermediates were not necessary to be isolated and 2-chlorotetrahydroquinolin-8-one was conveniently obtained with solvent slurry in 65% overall isolated yield in a four-step sequence.

Removal of wastewater phenolic compounds with triethylenetetramine functionalized polystyrene resin

A polyamine functionalized polystyrene resin (PSATA) was prepared via condensation reaction of acetylated polystyrene resin with triethylenetetramine, which, upon NaBH4 reduction, produced PSATAR. In comparison with the PSATA, the PSATAR with more flexible amine groups shows improved structural properties, and the equilibrium adsorption capacities of phenol, 2-nitrophenol (ONP) and 2,4-dinitrophenol (DNP) in wastewater were up to 1.073, 1.832 and 1.901 mmol/g, respectively. Their adsorption isotherms fit well with the Freundlich model, indicating a multilayer, heterogeneous adsorption nature. Kinetic studies indicated that the adsorption of phenolic compounds conforms to the pseudo-second-order kinetics with the adsorption rate controlled by film diffusion for ONP and DNP, and intra-particle diffusion in the later stage for phenol.

Facile Synthesis of Porous Hexapod Ag@AgCl Dual Catalysts for In Situ SERS Monitoring of 4-Nitrothiophenol Reduction

Controllable morphological metal catalytic materials have always been a focus in research. In the previous work, hexapod AgCl was successfully synthesized. In this paper, hexapod Ag@AgCl microstructures with diverse Ag contents are prepared through NaBH4 reduction. They are characterized by scanning electron microscopy (SEM) and the element distribution is proved by an energy dispersive X-ray spectrometer (EDS). They are porous dendritic microstructures with a large specific surface area and a rough surface, which display high catalytic performance and surface-enhanced Raman spectroscopy (SERS) activity. Furthermore, the hexapod Ag@AgCl microstructure is devoted as a dual catalyst to monitor the reduction of 4-nitrothiophenol (4-NTP) to 4-aminothiophenol (4-ATP) in situ using SERS. Ultraviolet–visible (UV–Vis) spectroscopy was employed to evaluate the catalytic performance of the hexapod Ag@AgCl microstructures. The consequences show that the velocity of reaction became faster with a corresponding increase in silver content and the reaction mechanism was cleared. In addition to preparing a good catalyst, this work also promotes the combination of micro-nano materials and spectroscopy technology.

Preparation of Pt/γ-Bi2MoO6 Photocatalysts and Their Performance in α-Alkylation Reaction under Visible Light Irradiation

Bi(NO3)3·5H2O and (NH4)6Mo7O24·4H2O were used as precursors to synthesize flaky γ-Bi2MoO6 samples by a hydrothermal method, and Pt/γ-Bi2MoO6 samples with different mass fractions were prepared by an NaBH4 reduction method. Alpha alkylation of benzyl alcohol and acetophenone with photocatalysts under visible light irradiation was performed, and the activity of 4 wt % Pt/γ-Bi2MoO6 (γ-Bi2MoO6 was prepared by a nitric acid method, pH = 9, and reaction temperature 180 °C) was the best. The photocatalytic reaction conditions were optimized by changing various kinds of variables, such as the type of catalyst, solvent, and base, and the amount of base, catalyst, and reactant. The optimal conditions for the organic reaction were 75 mg 4 wt % Pt/γ-Bi2MoO6, 6 mL n-heptane, 1.2 mmol NaOH, 1 mmol acetophenone, and 3 mmol benzyl alcohol. Under the optimal reaction conditions, the effects of different light wavelengths and light intensities on the reaction were measured, and the cycling ability of the photocatalyst was tested. After five cycles, the photochemical properties of the catalyst were relatively stable. Finally, the active substances were identified (such as electrons (e−), holes (h+), hydroxyl radicals (•OH), and superoxide radicals (•O2−).