Bis(4-nitrophenyl)phosphorylazide as a reagent for direct azidation of polyfunctional derivatives of pyrimidin-4(3<Emphasis Type="Italic">Н</Emphasis>)-one

The application of bis-(4-nitrophenyl)phosphorylazide–1,8-diazabicyclo[5.4.0]undec-7-ene system for direct transformation of polyfunctional derivatives of pyrimidin-4(3H)-one in the corresponding 4-azidopyrimidines has been suggested for the first time. Using this system, novel 4-azido-6-(2,6-dihalo-α-methoxybenzyl)-5-methyl-2-(nitroamino)pyrimidines have been obtained in good yield under mild conditions.     

Self-Organization and Analysis of the Morphology of Vacuum Evaporated Polyaniline Films

By using formal estimation methods, it is shown that heterogeneous redox structures, which are formed in the course of oxidation of vacuum evaporated thin polyaniline layers in the temperature range of 0–30°C, become more ordered with the increase in the oxidation temperature.     

X-ray diffractometry and electrical conductivity of the ceramics LaSrAl(Cu,Ni)O4

A continuous series of solid solutions LaSrAL_1−x Me_xO₄ (Me = Cu, Ni) has been investigated by x-ray diffractometry and by electrical conductivity measurements. The results are of interest from the standpoint of the theory of close-packing, percolation theory, and the theory of the cooperative Jahn-Teller effect. Fiz. Tverd. Tela (St. Petersburg) 39, 985–990 (June 1997)     

Spin-spin interactions of Ce3+ ions in the elpasolite crystal Cs2NaInCl6

The EPR method is used to study at T=4.2 K crystals of Cs₂NaInCl₆:Ce³⁺ (1 mol %) at which have elpasolite structure. A solitary cubic Ce³⁺ center and three types of Ce³⁺-Ce³⁺ pairs were observed, for which the spin-spin interaction parameters D and E were determined. It is established that deformation of the local structure results in a shift {Δg} of the pair relative to the g-factor of the solitary center. Models of the solitary center and the three types of Ce³⁺-Ce³⁺ pairs are discussed, as well as the nature of the spin-spin interactions in the pairs. The non-dipole nature of the interactions is established. Possible chains for the creation of an indirect exchange between the Ce³⁺ ions are considered. Fiz. Tverd. Tela (St. Petersburg) 39, 62–67 (July 1997)     

The adhesive properties of polyfluoroolefin films modified by direct-current discharge

The influence of the treatment of various structures polyfluoroolefine films by the direct-current discharge at the anode and cathode on the properties of the surface (the value of the contact angles of wettability, work of adhesion, and surface energy and its polar and dispersive components) is studied. Measurements of the peel strength of plasma-treated films are conducted. It is shown that the direct-current discharge treatment makes it possible to substantially increase the peel strength of the polyfluoroolefin films.     

Characteristics of the structural properties and the electric conductivity in LaSrAl1−x NixO4 ceramics caused by the Jahn-Teller effect

In studying LaSrAl_1−x Ni_xO₄ ceramics, anomalies are detected in the concentration dependences of the lattice parameter c, the electrical resistance, and the sign change of the Hall constant at x≈0.6. It is shown that the collection of observed phenomena can be interpreted as a manifestation of the Jahn-Teller nature of low-spin Ni³⁺ centers. Fiz. Tverd. Tela (St. Petersburg) 41, 418–422 (March 1999)