Structure of the 1:2 complex formed by the cis-anti-cis diastereomer of dicyclohexano-18-crown-6 with 2-methylbenzenesulfamide

Applied Physics Institute, Moldovian Academy of Sciences. Technical Physics Institute, Ukrainian Academy of Sciences. Translated from Zhurnal Strukturnoi Khimii, Vol. 33, No. 2, pp. 138–144, March–April, 1992.     

NMR Spectra of Guest–Host Complexes of Boron and Silicon Fluorides with Crown Ethers in Nonaqueous Solutions

¹⁹F, ¹¹B, and ²⁹Si NMR spectroscopy was used to examine the behavior of the guest–host complexes (BF₃· H₂O)₂· 18-crown-6 · 2H₂O, (BF₃· H₂O)₂· DCH-6B, and (DCH-6A · H₃O)SiF₅in acetone (DCH-6B and DCH-6A are the cis-anti-cis- and cis-syn-cis-isomers of dicyclohexano-18-crown-6, respectively). It was shown that molecular boron fluoride complexes undergo partial solvolysis in acetone to yield BF₃· acetone as the main product; the ionic pentafluorosilicate complex does not experience significant solvolysis transformations.     

Synthesis and structures of molecular complexes of the cis-anti-cis diastereomer of dicyclohexano-18-crown-6 with o-nitroanilines

In the reaction of the cis-syn-cis and cis-anti-cis diastereomers of dicyclohexano-18-crown-6 with 2-nitro and 2,4-dinitroaniline crystalline complexes with a 1:2 stoichiometric composition were obtained only when the cis-anti-cis diastereomer was used. The three-dimensional structure of the complex of the cis-anti-cis diastereomer of dicyclohexano-18-crown-6 with 2,4-dinitroaniline was determined by an x-ray diffraction study. The complexing of o-nitroanilines with the cis-anti-cis diastereomer is explained by the topological conformity of the interacting compounds. The isolation of the individual cis diastereomers from the mixture of them formed as a result of the catalytic hydrogenation of dibenzo-18-crown-6 was accomplished by means of the selective formation of the crystalline complex of the cis-anti-cis diastereomer with 2-nitroaniline.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1190–1195, September, 1988.     

Crystal structure of hydrazine 5-amino-1-benzyl-1,2,3-triazole-4-carboxylate hexafluorosilicate trihydrate

Hydrazine 5-amino-1-benzyl-1,2,3-triazole-4-carboxylate hexafluorosilicate trihydrate (I) is synthesized. The crystal structure of the compound synthesized is determined. Crystals I are monoclinic, a = 13.353(1) Å, b = 21.094(2) Å, c = 20.233(2) Å, β = 94.05(3)°, space group P2₁/c, and R = 0.0584 for 16 601 reflections with I > 2σ(I). In the asymmetric part of the unit cell, four organic cations protonated at the terminal hydrazine nitrogen atoms, two hexafluorosilicate anions, and six water molecules are linked into a three-dimensional framework through hydrogen bonds of the N-H?F, N-H?O, and O-H?F types.     

Interaction of cis-diastereomers of dicyclohexano-18-crown-6 with maleic anhydride and some “small” polar molecules

The cis-anti-cis diastereomer of dicyclohexano-18-crown-6 with maleic anhydride or formamide gives a crystalline complex of ratio 12. The three-dimensional structure of the former was found from x-ray studies. The formation of complexes was used for the separation of the individual cis-syn-cis and cis-anti-cis diastereomers from a mixture. Crystallization of a cis-anti-cis diastereomer from DMFA, DMSO, and N-methylpyrrolidine gave a high melting form.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1329–1332, October, 1989.     

Synthesis and structure of 13- and 26-membered crown ethers,derivatives of resorcinol

13- and 26-Membered crown ethers have been synthesized based on resorcinol and 1,8-dichloro-3,6-dioxaoctane. The products with substituents in the benzene ring have been prepared by alkylation of 13-membered crown ether. Complexing properties of the macrocycles have been studied with the use of ion-selective membrane electrodes. The structures of 13- and 26-membered crown ethers have been established by X-ray structural analysis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2458–2464, December, 1995.The work was supported by Technical University of Gdansk (Project DS No. 946197/003).     

Structural Aspects of Fluorosilicic Acid Reaction with Organic Bases

The results of systematic studies into the structures of products formed in reactions between fluorosilicic acid (FSA) and organic bases are presented. Different hydrolytically labile silicon fluoride complexes contained in these products are stabilized. A debatable problem of FSA state in aqueous solutions is discussed in the light of the data obtained.