Crystal Chemistry of Rare-Earth Chalcogenides

Crystal structures of Ln–X, Ln–Ln'–X, Ln–M–X, and Ln–X–Z compounds (Ln and Ln' are rare-earth elements; M is subgroup I–VIIIa or II–Vb cation and Z is subgroup V–VIIb anion; X is S, Se, or Te) were systematized and analyzed using data obtained by us and data from the literature. The structures of binary Ln–X chalcogenides can be divided into 4 groups: derivatives of NaCl-type structures, structures with one small parameter b 4 Å, structures similar to those of oxides and pniktides, and derivatives of PbFCl-type structures. Triple Ln–Ln'–X chalcogenides have structures similar to those of the binary chalcogenides of the first, second, and third groups. It was shown that the crystal structure of Ln–M–X depends on the size of cation M, its formal charge, electronegativity value, and electronic structure. The crystal structures of the phases in the Ln–M–X and Ln–X–Z compounds were compared with binary chalcogenide structures. Different variants of structure characterization and their potentialities are considered. Special attention is given to the defect-containing and ordered structures and to elucidating the role of the cation and anion vacancies in the phase structures.     

Triterpene glycosides of Gypsophila trichotoma V. The structure of trichoside D

Summary The structure of the glycosidic carbohydrate chain and the partial structure of the acyloside chain of trichoside D — a new triterpene glycoside fromGypsophila trichotoma — have been established.Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 69–72, January–February, 1972.     

Molecular Structure of γ-Apienes. Crystal and Molecular Structure of Ferocin

The molecular structure of the sesquiterpene humulene ester ferocin isolated from plants of the Ferula genus was determined by x-ray structure analysis. The conformation of the 11-membered γ-humulene ring was analyzed by molecular mechanics. It was found that four energetically similar macrocycle conformations are characteristic of γ-apienes.__________Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 125–128, March–April, 2005.     

X-ray structural investigation of gossypol and its derivatives XX. Structure of the solvate of gossypol with pyridine

The structure of the solvate of gossypol with pyridine has been determined by x-ray structural analysis. The crystalline solvate is a H-clathrate with the channel type of structure in which there are three pyridine molecules to each host molecule. On the desolvation of gossypol tripyridine, a new polymorph is formed.Communications (XI–XIX) are represented by the publications given in the Literature Cited under Nos. 1–9.Institute of Bioorganic Chemistry, Uzbekistan Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 186–191, March–April, 1992.     

Electroconductivity of NaF–NaCl–ZrF4 Melts

Electroconductivity of NaF–NaCl–ZrF₄ melts is studied in a wide temperature and concentration range. The molar electroconduction and its deviation from additive values are calculated. The concentration dependences of obtained and calculated properties of molten NaF–NaCl–ZrF₄ nicely fit a complex model for the structure of ionic liquids.     

Structure of the Products of the Oxidation of Diphenylamine, the First Member in a Family of Analytical Redox Reagents

The structure of the product of diphenylamine oxidation in acid solutions was indirectly confirmed within a quantum-chemical approach based on extrapolation from molecular fragments to the molecule using the Pariser–Parr–Pople method.     

Development of the specific surface areas of natural coal in the course of thermolysis in the presence of potassium hydroxide

The development of the surface of natural coal from Donets field in the course of thermolysis with KOH was studied. The dependences of the specific surface area of coal containing 90% carbon on the activation time, temperature (400–800°C), and KOH/coal ratio (0.75–4.5 g g^–1) were determined. The effect exerted on the development of the porous coal structure by low-temperature (20±2°C) oxidative modification causing formation of oxygen functional groups and reorganization of the coal three-dimensional structure was studied.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 9, 2004, pp. 1452–1455.Original Russian Text Copyright © 2004 by Tamarkina, Kucherenko, Shendrik.     

Study of the Influence of the Preparation Method on the Formation of the Phase Composition and Structure of V–Ti–O and W–Ti–O Catalysts for Selective Catalytic Reduction of NO by NH3

The influence of the preparation method on the structure and phase composition of V–Ti–O and W–Ti–O catalysts for selective catalytic reduction of NO by NH₃ was studied. The preparation conditions were found to insignificantly affect the structure of the resulting V–Ti–O catalysts, whereas in the case of W–Ti–O catalysts, such an influence was distinctly observed. The introduction of tungsten ions into the lattice of titanium dioxide leads to the formation of both local defects (solid solutions of the substitution type) and extended, so-called Wadsley's defects in the framework of TiO₂. The concentrations of the defects of both types depend on the catalyst preparation conditions.     

Structure of diptocarpilidine

Diptocarpilidine (bp 193–194° (4 mm)) has been isolated from the epigeal part and seeds ofDiptychocarpus strictus (Fisch) Trautv., and its structure has been established as 1-cyano-6-methylsulfinylhexane.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 84–86, January–February, 1984.     

The structure of nutanoside

Summary The complete structure of nutanoside — a triterpene glycoside isolated from the roots ofSilene nutans L. — has been established.A. E. Arbuzov Institute of Organic and Physical Chemistry, Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 412–416, July–August, 1971.     

Structures of three molybdenum(0)–tetracarbonyl–Schiff base compounds

The structures of three molybdenum(0)–tetracarbonyl–Schiff base compounds, determined by X-ray diffraction techniques, are reported. The Schiff bases are those derived from 2-acetylpyridine and 4-methoxyaniline, 4-trifluoromethoxyaniline, or 3-fluoro-4-methylaniline. The structure of the Schiff base ligand has also been determined for the ligand derived from 4-trifluoromethoxyaniline. Comparisons are made between metal–nitrogen bond distances, and carbon–nitrogen and carbon–carbon bond distances in the chelate rings, for these and a number of related molybdenum(0)–tetracarbonyl-diimine compounds. Comparisons are also made between ligand geometry in the free and coordinated states.     

Triterpene glycosides of Gypsophila patrinii III. The structure of philoside B

Summary The structure of philoside B — a gypsogenin nonaoside isolated from the roots ofGypsophila patrinii — has been established.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan'Branch, Academy of Sciences of the USSR. Correspondence Institute of Soviet Commerce. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 603–607, September–October, 1974.     

X-ray structure analysis of triacetyllagochilin and lagochilin tetraformate

The molecular structures of two diterpene lagochilins, triacetyllagochilin and lagochilin tetraformate, are determinated by x-ray structure analysis.Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 142–144, March–April, 2000.     

X-ray structural investigation of gossypol and its derivatives XXII. Structure of the H-clathrate of gossypol with dimethyl sulfoxide

In crystals obtained from solutions in DMSO, gossypol molecules are again present in the aldehyde tautomeric form. These crystals are H-clathrates with the channel type of structure which has much in common with the structure of the complexes of gossypol with methanol and with formic acid.Institute of Bioorganic Chemistry, Uzbekistan Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, Nos. 3,4, pp. 330–334, May–August, 1992.     

Dependence of the physiological activity of the sulfur-containing alkaloids ofdipthychocarpus strictus on their chemical structure

A dependence of the physiological activity of the sulfur-containing alkaloids ofDipthychocarpus strictus on their structure has been reveated.Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 417–419, May–June, 1997.     

Decarboxylation products of echinocystic acid

Summary 1. The structure of norechinocystenolone has been established and it has been shown to be identical with the natural nortriterpene albigenin.2. The isomerization of isonorechinocytenedione into norechinocystenedione consists in the migration of a double bond from 12–13 position to the 13–18 position.Khimiya Prirodnykh Soedinenii, Vol. 3, No. 4, pp. 230–235, 1967     

Phytoecdysteroids of plants of the genusRaphonticum II. Carthamosterone b fromRh. carthamoides

The structure of a new ecdysteroid — carthamosterone B, isolated from the seeds ofRhaponticum carthamoides — has been established from an investigation of its spectral characteristics.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 40 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 395–396, May–June, 1997.     

Triterpene glycosides of Dianthus deltoides II. Structure of dianthoside C

Summary The structure of dianthoside C — a triterpene glycoside fromDianthus deltoides L. — has been established.A. E. Arbuzov Institute of Organic and Physical Chemistry, Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 420–425, July–August, 1971.     

Mechanochemical Complexation between Deoxycholic Acid and Salicylic Acid

A complex between deoxycholic acid (DCA) and salicylic acid (SA) was prepared by grinding and coprecipitation methods. The resultant complex was characterized by means of powder X-ray diffractometry, IR spectroscopy and thermal analysis. The stoichiometry (DCA : SA 1 : 1) of the complex obtained by grinding was identical to that obtained by coprecipitation. The powder X-ray diffraction pattern of the DCA–SA complex differed from the typical pattern of DCA–guest complexes such as DCA–camphor and DCA–phenanthrene complexes. IR spectra suggested that a different kind of hydrogen bonding was formed in the crystal of the DCA–SA complex, compared with the other DCA–guest complexes. This was in good agreement with data from the crystal structure.