Raman Scattering Study of Natural and Synthetic Compounds Containing Polyene Chains

Doklady Physics - The dependence of Raman spectra of the molecules containing polyene chains on the conjugation length, structure of side and end groups, and isomer type is analyzed theoretically.     

Three-Dimensional Structure of Thermostable D-Amino Acid Transaminase from the Archaeon Methanocaldococcus jannaschii DSM 2661

Crystallography Reports - Pyridoxal 5′-phosphate (PLP)-dependent transaminases catalyze the stereospecific amino-group transfer from an amino acid or amine to ketone or keto acid....     

Complexes of Phosphorus-containing Cyclophanes and Cryptands with Metals,Anions, and Organic Substrates

Russian Journal of Organic Chemistry - New data since about 2010 concerning complex formation of phosphorus-containing cyclophanes and cryptands with transition metals, as well as guest-host...     

Peculiarities of the phase composition and structure of the high-entropy FeWMoCrVSiMnC multicomponent steel

We report on the results of analysis of the phase composition, structure, and hardness of high-entropy FeWMoCrVSiMnC multicomponent steel subjected to synthesis and subsequent thermal treatment. Analysis is carried out using the methods of analytic transmission and scanning structural and orientational electron microscopy, optical metallography, X-ray energy-dispersive spectroscopy, X-ray phase and structural analyses, and Rockwell measurements of hardness. It is found that steel has a high hardness (62 HRC) and is in ultra-fine-disperse composite martensite-multicarbide state. All carbides are distributed uniformly over the steel volume and have nano- and submicrometer scales depending on the carbide type.

     

The Effect of Supports of Glassy–Carbon and Activated Graphite Foil on the Electrochemical Behavior of Composite Coatings Based on Polyaniline and Its N-Substituted Derivatives

Russian Journal of Electrochemistry - Abstract—Hybrid polymer nanomaterials are synthesized based on polyaniline (PAni) and its N-substituted derivative...     

Screening of Conditions that Facilitate Crystallization of Oligopeptidase B from Serratia Proteamaculans by Differential Scanning Fluorimetry

Crystallography Reports - Oligopeptidases B (OpdBs) are two-domain serine peptidases with trypsin-like substrate specificity belonging to the prolyl oligopeptidase family. These enzymes are...     

Synthesis and electrochemical properties of nanocomposites containing poly(3,6-bis(phenylamino)-2,5-dichlorobenzoquinone and multiwalled carbon nanotubes

The method of synthesizing nanocomposites based on multiwalled carbon nanotubes and a new polymer poly(3,6-bis(phenylamino)-2,5-dichlorobenzoquinone) containing polyaniline chains with electroactive substituents in the N-position is developed, and the electrochemical properties of the composites are studied. The in situ oxidative polymerization of N-substituted aniline performed in the presence of multiwalled carbon nanotubes makes it possible to design an organized, effective structure of the conducting composite material with enhanced electrochemical capacity and stable capacity parameters during long cycling in protic (1 mol/L H₂SO₄) and aprotic (1 mol/L LiClO₄ in propylene carbonate) electrolytes.     

Synthesis and study of immobilized porphyrins on the basis of acrylic polymer carriers

In order to obtain porphyrin-containing polymers, the copolymerization of acrylate monomers of the various structures with natural porphyrin, namely methyl pheophorbide a (MPP) and its complex with copper (CuMPP) in tetrahydrofuran and toluene was studied. The copolymers of methyl methacrylate (MMA) with MPP or CuMPP, glycidyl methacrylate (GMA) with MPP or CuMPP having different compositions were synthesized. The influence of the nature of the solvent, the initial mass ratio of the monomers during copolymerization on the structure, composition, and properties of the obtained compounds were investigated. The study of the physico-chemical, molecular weight, structural, and chemical characteristics of the prepared copolymers was carried out. The possibility of controlled synthesis of the copolymers with controlled molecular weight characteristics by varying the parameters of the reaction medium was shown.

     

Conformational polymorphs of 3‐cyclopropyl‐5‐(3‐methyl‐[1,2,4]triazolo[4,3‐a]pyridin‐7‐yl)‐1,2,4‐oxadiazole

The dipharmacophore compound 3‐cyclopropyl‐5‐(3‐methyl‐[1,2,4]triazolo[4,3‐a]pyridin‐7‐yl)‐1,2,4‐oxadiazole, C₁₂H₁₁N₅O, was studied on the assumption of its potential biological activity. Two polymorphic forms differ in both their molecular and crystal structures. The monoclinic polymorphic form was crystallized from more volatile solvents and contains a conformer with a higher relative energy. The basic molecule forms an abundance of interactions with relatively close energies. The orthorhombic polymorph was crystallized very slowly from isoamyl alcohol and contains a conformer with a much lower energy. The basic molecule forms two strong interactions and a large number of weak interactions. Stacking interactions of the `head‐to‐head' type in the monoclinic structure and of the `head‐to‐tail' type in the orthorhombic structure proved to be the strongest and form stacked columns in the two polymorphs. The main structural motif of the monoclinic structure is a double column where two stacked columns interact through weak C—H…N hydrogen bonds and dispersive interactions. In the orthorhombic structure, a single stacked column is the main structural motif. Periodic calculations confirmed that the orthorhombic structure obtained by slow evaporation has a lower lattice energy (0.97 kcal mol^?1) compared to the monoclinic structure.     

Two-Layer Heavy-Fluid Flow past a Vortex when the Stream Is Divided by a Semi-Infinite Plate

The problem of two-layer heavy inviscid fluid flow past a vortex in the presence of a semi-infinite plate on the interface when the fluids have different densities and velocities at infinity is solved in the linear approximation. The forces exerted on the vortex and the plate and the shape of the interface are determined as functions of the location of the vortex, its intensity, the Froude number, the free-stream density ratio and the velocities.