Chalcogenation of 1,4-dichlorobut-2-yne with organic dichalcogenides in the system hydrazine hydrate–KOH

A reaction of organic dichalcogenides R₂Y₂ (R = Ph, Bn, Pr; Y = S, Se) with 1,4-dichlorobut-2-yne in the system hydrazine hydrate–KOH leads to four principal products: 1,4-bis(organylchalcogenyl)but-2-ynes, 1-organylchalcogenylbut-1-en-3-ynes, 4-organylchalcogenylbut-1-en-3-ynes, and 3(5)-methylpyrazole. The selectivity of the formation of individual products is determined by the ratio of the substrates used and the reaction temperature. A plausible mechanism of chalcogenation considered in the work agrees with the effect of the nature of chalcogene atoms and organic substituents R on stability of intermediates and products. The stabilization of carbanions by α chalcogene-containing groups corresponds to the following order: PhS > PhSe > BnS > BnSe > PrS.     

Interaction of amorphous and crystalline nickel nanoparticles with hydrogen

Nickel nanoparticles were deposited on the surface of highly oriented pyrolytical graphite by laser electrodispersion and precipitation from a solution of reverse micelles. The particles were studied using scanning tunneling microscopy and spectroscopy as well as Auger spectroscopy. The elemental composition of the nanoparticles and specific features of the electronic structure of their surface were determined. Adsorption of molecular hydrogen was also studied.     

Electrodeposited paint-and-varnish nickel–polymer coatings

Specific features of preparation of paint-and-varnish nickel–polymer coatings by joint cathodic electrodeposition of an amine-containing oligomeric electrolyte and nickel were studied. The coatings obtained exhibit layer-by-layer heterogeneity, with the lowest layer constituted by an intermetallic compound of nickel with iron. The coatings are characterized by higher degree of cross-linking compared to the polymer coatings without nickel. A paint-and-varnish formulation based on a nickel–polymer film-forming agent was developed for electrodeposition of corrosion- and wear-resistant coatings.     

Design and synthesis of an octavalent bolaamphiphile with terminal lactose residues

The synthesis of an octavalent bolaamphiphile with D-glucose moiety as branching unit has been designed and accomplished via 1,3-dipolar cycloaddition of bis(tetra-O-propargylglucoside) and 8 equiv of 2-azidoethyl β-D-lactoside.     

Application of polymethyl methacrylate in cathode materials of lithium-ion batteries

A study of the Li₂FeSiO₄/C cathode material doped with Mn demonstrated that introduction of polymethyl methacrylate results in a substantial decrease in the particle size and increase in the specific surface area of the cathode material. Polymethyl methacrylate strongly improves the cyclic stability of the cathode material. The discharge capacity after the first cycle was 218 mA h g^–1, and that upon stabilization of the structure of the cathode material, 170 mA h g^–1.     

Reaction of 2,3-dibromo-3-nitroacrylates with N-amino-N″-nitroguanidine

Russian Journal of Organic Chemistry -     

Structural Characterization of O‐ and C‐Glycosylating Variants of the Landomycin Glycosyltransferase LanGT2

The structures of the O‐glycosyltransferase LanGT2 and the engineered, C? C bond‐forming variant LanGT2S8Ac show how the replacement of a single loop can change the functionality of the enzyme. Crystal structures of the enzymes in complex with a nonhydrolyzable nucleotide‐sugar analogue revealed that there is a conformational transition to create the binding sites for the aglycon substrate. This induced‐fit transition was explored by molecular docking experiments with various aglycon substrates.     

Metal‐Catalyzed “On‐Demand” Production of Carbonyl Sulfide from Carbon Monoxide and Elemental Sulfur

The group 6 molybdenum(II) cyclopentadienyl amidinate (CPAM) bis(carbonyl) complex [Cp*Mo{N(iPr)C(Ph)N(iPr)}(CO)₂] (Cp*=η⁵‐C₅Me₅) serves as a precatalyst for the high‐yielding photocatalytic production of COS from CO and S₈ under near‐ambient conditions (e.g., 10 psi, 25 °C). Further documented is the isolation and structural characterization of several key transition‐metal intermediates which collectively support a novel molybdenum(IV)‐based catalytic cycle as being operative. Finally, in the presence of an excess amount of a primary amine, it is demonstrated that this catalytic system can be successfully used for the “on‐demand” generation and utilization of COS as a chemical reagent for the synthesis of ureas.