The Influence of Solvents on the Alkylation of Carboxylate Phosphabetaines with Alkyl Iodides

The new alkylation reactions of a series of mono- and dicarboxylate phosphabetaines with methyl and ethyl iodides in different solvents have been studied. These reactions have afforded stable compounds: iodine-containing salts of phosphonium with different structure.     

Inverse magnetoelectric effect in disk-shaped samples of ferrite piezoelectric composites

A theory of the inverse magnetoelectric effect in the vicinity of electromechanical resonance in disk-shaped samples is presented. An expression for the coefficient of the inverse magnetoelectric transformation has been obtained using the effective parameter method. It has been shown that a sharp increase in the magnitude of the effect occurs at a frequency of electromechanical resonance, and the resonance frequencies for the direct and inverse magnetoelectric effects are different. The dependences of the resonance frequencies on the ferrite percentage in ferrite-nickel spinel samples and lead zirconate titanate samples have been studied experimentally.     

Bolometric detector embedded in a polycrystalline diamond grown by chemical vapor deposition

A fast bolometric detector embedded in a plate of chemical-vapor-deposited polycrystalline diamond was developed and fabricated. The working element of the bolometer is a buried graphitized layer (with temperature-sensitive resistance) fabricated in the bulk of a diamond by C⁺ ion implantation followed by annealing. The kinetics of the response of the structure to irradiation with light from an LGI-21 pulsed nitrogen laser (λ = 337 nm, τ_P ～ 8 ns) were studied. The room-temperature response width at half-maximum is ～ 20 ns. Using the space-time distribution of responses of the structure, thermal (bolometric) signals were resolved from signals of different nature (photoconductivity or photovoltage).     

Large-radius dynamic topological solitons in uniaxial ferromagnets

In thin ferromagnetic films with perpendicular anisotropy, there exist stable large-radius dynamic topological solitons, which are stabilized owing to conservation of the orbital angular momentum of the magnetization field. The solitons can also exist if the projection of the total spin moment of the magnet onto the easy axis is not conserved, i.e., in the absence of pure uniaxial symmetry of the model. Even in the pure uniaxial case, the magnetization distribution in a soliton with a sufficiently large radius differs significantly from centrosymmetric.     

Synthesis and Antioxidant Activity of Sterically Hindered Phenol Derivatives of Carboxy- and Sulfobetaines

New multifunctional antioxidants based on carboxy- and sulfobetaines with sterically hindered phenol fragments were synthesized. The antioxidant capacity of the compounds determined in the reactions of their oxidation by electrogenerated bromine is comparable to that of ascorbic acid and ionol.     

5-Amino-Substituted Derivatives of 4-Nitrofurazane: Synthesis,Structure, and Biological Activity

New amination reactions of 5-chloro-4-nitrobenzofurazane with different amines were studied. The reactions of 5-chloro-4-nitrobenzofurazane with 2,4,6-trichloro-, para-acetyl-, and para-carboxyethylanilines gave the products of aromatic nucleophilic substitution of the chlorine substituent in the nitrogenous heterocycle, the composition and structure of which was established by chemical, physical, and physicochemical methods and X-ray diffraction analysis. The thermal stability was studied by synchronous thermogravimetry and differential scanning calorimetry (TG?DSC). The synthesized compounds showed a high antibacterial and antimycotic activity against human and animal pathogenic microflora.     

The Reactivity of Ferrocene and Its Derivatives in the Reaction with Quinines

The reactivity of ferrocene derivatives with respect to p-quinones in acid media has been studied. A tentative mechanism of oxidation of ferrocene with p-qionone in acid media including two-step reduction of p-quinone to hydroquinone is proposed.     

Electrophilic 1,3-C→N− and-N→C− migrations in saturated systems

A new type of intramolecular electrophilic rearrangements involving the shift of COOAlk groups from carbon to an N-anionic center is considered. Carbanionic species with COOAlk groups at anionic centers containing no acidic hydrogen react unusually with alkyl(aryl) iso(thio)cyanates giving carbamates as a result of insertion of RNCX into the C−C bond. The kinetics and mechanism of insertion of aryl isocyanates into the C−C bond of the phosphonium zwitterion obtained from triisopropylphosphine and ethyl 2-cyanoacrylate are discussed. The reaction of α-carbanions derived fromN,N-disubstituted amides with methyl trifluoromethanesulfonate results inO-methylation. Some possibilities of back N→C⁻ migrations are considered. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1643–1648, September, 1999.     

Potentiometric Titration of Some Sulphide Forming Ions by Dithiopyrilmethane

Dithiopyrilmethane (DTPM) is the sulphur containing derivative of pyrazolone. This reagent forms active mono- or biprotonated form giving stable, often colored complexes with sulphide forming metal ions. It is the most common that the reagent as a bidentate neutral ligand exists in these complexes giving cation or neutral complexes. This reagent is used in spectrophotometric and extractive spectrophotometric methods of analysis of sulphide forming metal ions.