Multinuclear compounds of s-elements with sterically hindered <Emphasis Type="Italic">о</Emphasis>-semiquinonates and catecholates

Alkali metals form mutinuclear compounds with redox-active singly and doubly reduced derivatives of sterically of hindered о-benzoquinones. Complexes [Na₆(Cat)₃(THF)₇]?4THF, [Na₅(Cat)₂(SQ)(THF)₅], [Na₄(SQ)₄(THF)₄]?THF?C₆H₁₄, [Na₄(3,5-SQ)₄(THF)₄], [K₄(SQ)₄(THF)₄]?4THF and [Li₃(SQ)₃(THF)₃]?THF (Cat is catecholate, SQ is semiquinonate) possessing high sensitivity to atmospheric oxygen were synthesized and their structures were determined. Magnetochemical measurements and quantum chemical calculations revealed that variation of the alkali metal and/or change in the structure of the polymetallic core significantly affect the energy of exchange interaction between the unpaired electrons of the paramagnetic ligands framing the polynuclear metal core formed by s-elements.     

A phenomenological model for hydrocarbon high-temperature autoignition

A four-step phenomenological chemical–kinetic model is presented that is believed to apply to many aspects of combustion of most hydrocarbons at temperatures above about 1000 K. The mechanism involves chain initiation through reactive collision of fuel and oxidizer molecules, fuel consumption in a step that removes radicals, oxidizer consumption in a step that produces radicals and a chain termination step. An expression for the autoignition time is derived on the basis of this model and is applied to describe the ignition of propane–air mixtures and a few other hydrocarbons. It is shown that excellent agreement with ignition times obtained from detailed chemistry can be achieved by this model.     

Kinetic study of the reaction of nucleophilic cyclopropanation of C60 fullerene with halogenated maleopimarimide

The kinetics of nucleophilic fullerene cyclopropanation by halomethyl ketones with a diterpene fragment has been studied by the Bingel method, and the influence of the biologically active cyclopropanating agent on the process has been estimated. It has been revealed that favorable conditions for carrying out the reaction result in maximum monofunctionalized methanofullerenes formation with the maximum yield.     

Studying the physical properties of entangled electron spin states in a solid body

A concept for the experimental study of the physical properties of entangled electron spin states in a solid body is proposed. The construction of the experimental setup is developed. New-generation electron spin detectors are created. Test measurements of the electron spin polarization by two simultaneously operating Mott detectors are carried out. It is found that Bell’s inequalities are satisfied in the traditional measurement mode (without time coincidences of the pulses).     

Use of galvanostatic coulometry in the analysis of arbidol drug

Arbidol is proved to easily and completely react with electrogenerated bromine in the ratio 2: 9; so procedures for the arbidol quantification in the neat substance and drugs are developed, the RSD value does not exceed 2%. A procedure for the coulometric determination of water in the arbidol substance using the Fisher method is proposed.     

Olefin Synthesis via,the Li-Derivative of N,N,N′,N′-Tetramethyldimides of Arylmethanephosphonic Acids

Abstract

The high erythro-stereoselective reaction of Li-tetramethyldiamides of arylmethanephosphonic acids with carbonyl compounds is used for synthesis of (Z)-alkenes by thermolysis of the erythro-adducts as well as in acidic media.     

Investigation of the molecular mobility of peptin macromolecules using photon-correlation spectroscopy

The pH dependence of the intermolecular interaction coefficient of pepsin in an aqueous solution is obtained by using photon-correlation spectroscopy. The dependence shows a minimum near the isoelectric point (pH 1.6). The dynamic parameters of pepsin macromolecules in solutions containing various metal ions, including potassium, cobalt, lead, cesium, and rubidium are studied. It is shown that the addition of these ions causes a decrease of the translational diffusion coefficients. It is found that an increase in temperature leads to the structural transition of a pure solution of pepsin in water. The activation energy of this transition is calculated using the Arrhenius law.     

Mechanical properties and energy dissipation in ultrafine-grained AMts and V95 aluminum alloys during dynamic compression

The thermomechanical characteristics of ultrafine-grained AMts and V95 aluminum alloys with an average crystallite size of 200–600 nm are experimentally studied during dynamic compression. The alloys are fabricated by dynamic channel angular pressing. It is found that the deformation history of the alloys and the initial characteristics of their structural state affect the subsequent plastic deformation and the dissipation of applied energy. The studies of the thermodynamics of deformation in combination with structural investigations before and after dynamic compression allowed us to reveal the main structural relaxation mechanisms in the materials during dynamic compression and to determine the dissipation abilities of various defect structures.