Growth and study of single crystals of (Na,K)NbO<Subscript>3</Subscript> solid solutions

(Na, K)NbO₃ crystals with a perovskite structure and a KNbO₃ content up to 40 mol % were grown from flux with the use of the solvent NaBO₂. The dielectric measurements of the crystals grown revealed phase transitions that had never been observed before in ceramic samples.     

Research in the imidazole series. 96. Reaction of 1-methyl-4-nitro-5-chlorimidazole with phenols, naphthols, and 8-hydroxyquinoline

By reactions of 1-methyl-4-nitro-5-chlorimidazole with 4-nitrophenol, - and -naphthols, and 8-hydroxyquinoline, a number of 1-methyl-4-nitro-5-aryl(heteryl)oxyimidazoles have been obtained. With aminophenols, under analogous conditions, 1-methyl-4-nitro-5-hydroxyphenylaminoimidazoles have been obtained.For Communication 95, see [1].Novokuznetsk Scientific-Research Chemical-Pharmaceutical Institute, Novokuznetsk 654034, Russia. Center for Medicinal Chemistry, All-Russian Scientific-Research Chemical-Pharmaceutical Institute, Moscow 119815. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 327–329, March, 1998.     

Regioselective synthesis of 1-aryl-4-bromo-5-trifluoromethylpyrazoles

A novel regioselective route to 1-aryl-4-bromo-5-trifluoromethylpyrazoles involves reactions of arylhydrazines with 3-bromo-4-ethoxy-1,1,1-trifluorobut-3-en-2-one. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 167–168, January, 2006.     

Investigations in the imidazole series 97. Synthesis and some transformations of 5-nitro-5-hydroxyalkylamino- and 4-hydroxy-alkylamino-5-nitroimidazoles

A series of 1-alkyl(1,2-dialkyl)-substituted 4-nitro-5-hydroxyalkylamino- and 4-hydroxyalkylamino-5-nitro-imidazoles were obtained by the reaction of 1-alkyl(1,2-dialkyl)-substituted 4-nitro-5-chloro(bromo)imidazoles with amino alcohols. Their reactions with thionyl chloride and carboxylic acid halides and their catalytic hydrogenation were studied. For Communication 96, see [1]. Center of the Chemistry of Medicinal Agents, All-Russia Scientific-Research Chemical-Pharmaceutical Institute, Moscow 119815. Novokuznetsk Scientific-Research Chemical-Pharmaceutical Institute, Novokuznets 654034, Russia. Zaporozh'e State Medical University, Zaporozh'e 33074. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10. pp. 1346–1351, October, 1998.     

1,9,8-cyclization of 1,8-disubstituted anthraquinones. 12H-benzo[m,n]chromeno [2,3,4-k,l]kacridine derivatives

The cyclization of 1-(2,5-dihalophenylamino)-8-hydroxyanthraquinones or the corresponding 8-methoxycompounds in concentrated sulfuric acid has given derivatives of a new hexanuclear heterocyclic system —12H-benzo[m,n]chromeno [2,3,4-k,l]acridine. It has been shown that the double cyclization takes place initially through the closure of the pyridine ring with the formation of 9H-napth[3,2,1-k,l]acridine, the product of 1,9-cyclization. Under the reaction conditions the latter undergoes intramolecular aroxylation with the formation of a pyran ring under a-typical conditions.Translated from Khimiya GeterotsiklicheskikhSoedinenii, No. 4, pp. 519–523, April, 1980.     

Formation of a cluster structure in the PbZr<Subscript>1 – <Emphasis Type="Italic">x</Emphasis> </Subscript>Ti<Subscript> <Emphasis Type="Italic">x</Emphasis> </Subscript>O<Subscript>3</Subscript> system

Microdeformations of the crystal lattices in the phombohedral and tetragonal regions of the PbZr_1–xTi_xO₃ phase diagram have been calculated and their dependences on the titanium concentration have been constructed. Based on an analysis of these dependences, it has been concluded that tetragonal-phase clusters form in the range 0.11< x < 0.12 and rhombohedral-phase clusters form in the range 0.725 < x < 0.750.     

Ion conductivity,structural features,and multifractal properties of grain boundaries in CuCr<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>V<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>S<Subscript>2</Subscript>

The ion conductivity, crystal structure, and multifractal parameters of the sections of grain boundaries in CuCr_1?x V _x S₂ superionic conductors with 0 ≤ x ≤ 0.3 have been investigated. It is established that an increase in the surface area of grain boundaries and complication of their shape in such compounds facilitate ion transport. The effect of crystal structure peculiarities on the grain structure of these compounds has been revealed.     

Structure, dielectric, magnetoelectric, and dissipative properties of AFe2/3W1/3O3 (A = Ba, Sr, Pb) ceramics in wide frequency and temperature ranges

High-density impurity-free AFe_2/3W_1/3O₃ (A = Ba(BWF), Sr(SWF), Pb(PWF)) ceramics with well-developed microstructures were synthesized. Their structures and dielectric properties were investigated over wide temperature (10–973 K) and frequency (25 Hz-1 MHz) ranges. These materials are found to be almost transparent in the microwave range. They were characterized by weak magnetoelectric interactions; ?(BWT) ≈ 50 up to 400 K and ?(BWT) and ?(PWT) have second maxima between 400 and 600 K. All properties are easily reproduced, regardless of slight variations in synthesis conditions.     

Spectral‐Luminescence and Generation Properties of 1‐Aza‐2‐Methyl‐6‐Aminopyrene and of Its Protolytic Forms

Spectral manifestations of protolytic forms of 1aza2methyl6aminopyrene in ethanol and aqueous solutions are investigated. The ionization constants of the protolytic forms are determined. The generation properties and photostability of a neutral molecule and a cation in excitation by an excimer XeCl laser are studied.     

Crystal chemical simulation of low-permittivity ferroelectrics

It is shown that the uniform strain parameter of the unit cell of solid solutions of alkali metal niobates can be raised and their permittivity can drastically be decreased by isovalent superstoichiometric modification in the A subcell. The underlying mechanism is suggested. It is concluded that these findings are helpful in studying (simulating) piezoelectric ferroelectrics of practical value.