(O-Si)-Chelate acetic and benzoic acid N-(fluorosilylmethyl)amides: synthesis and structure

Russian Chemical Bulletin - New representatives of (O-Si)-chelate compounds, N-(fluorosilyl)methyl derivatives of N-methylacetamide, N-methylbenzamide, N-phenylacetamide, and N-phenylbenzamide,...     

Intra- and intermolecular hydrogen bonding in solutions of <Emphasis Type="Italic">N</Emphasis>-(2-hydroxy-3,8-diiodocyclooctyl)trifluoroacetamide and <Emphasis Type="Italic">N</Emphasis>-(4-iodo-2,2,5,5-tetramethyltetrahydrofuran-3-yl)trifluoroacetamide

The methods of IR spectroscopy and quantum chemistry (B3LYP/DGDZVP) were applied to investigation of the types of self-associates formed in solutions of N-(2-hydroxy-3,8-diiodocyclooctyl)trifluoroacetamide and N-(4-iodo-2,2,5,5-tetramethyltetrahydrofuran-3-yl)trifluoroacetamide in CCl₄ by means of hydrogen bonding. The ОН group of N-(2-hydroxy-3,8-diiodocyclooctyl)trifluoroacetamide participates in the formation of intramolecular hydrogen bond ОH···О=С, while chain dimers are formed due to interactions between the NH and С=О groups of the neighboring molecules. Due to the formation of the intramolecular bond, the dimers of N-(2-hydroxy-3,8-diiodocyclooctyl)trifluoroacetamide are energetically less stable than the chain dimer of N-(4-iodo-2,2,5,5-tetramethyltetrahydrofuran-3-yl)trifluoroacetamide.     

Solution of the perturbation problem for a shear flow with nonmonotonic velocity profile

Novosibirsk State University, Novosibirsk 630090. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 36, No. 5, pp. 7–15, September–October, 1995.     

Oxidative sulfamidation of vinyl silanes: A route to diverse silylated N-Heterocycles

The reaction of trimethyl(vinyl)silane 1 and dimethyl(divinyl)silane 2 with various sulfonamides in the oxidative system (tert-BuOCl + NaI) has been studied and shown to be an efficient approach for the synthesis of silylated N-heterocycles. Triflamide demonstrated the reactivity principally different from that of arenesulfonamides. With silane 1, it afforded the products of iodochlorination and bis(triflamidation) (major), whereas arenesulfonamides gave N-arenesulfonylaziridines in up to 91% yield. Silane 2 with arenesulfonamides yielded the products of mono and bis(iodochlorination), mono and bis(aziridination), and 3,5-diiodo-4,4-dimethyl-1-(arylsulfonyl)-1,4-azasilinanes. By contrast, triflamide, apart from the products of halogenation and iodotriflamidation, unexpectedly gave 3-(trifluoromethylsulfonyl)-5-(triflamido)oxazolidine as the main product. The structure of most heterocyclic products is proved by X-ray analysis. The effect of the silyl group in the substrate and of the substituent in the reagent on the course of oxidative sulfamidation is discussed by comparing with all-carbon analogues.     

Urea and thiourea complexes with trifluoromethanesulfonic acid and its derivatives

Urea and thiourea form complexes with trifluoromethanesulfonic acid, its monohydrate, and lithium salt CF₃SO₃Li. Urea complexes with trifluoromethanesulfonic acid are also formed as a result of hydrolysis in the reaction of N,N′-bis(trimethylsilyl)carbodiimide or cyanamide with trifluoromethanesulfonic acid in water.     

Crystal and molecular structures of Si-(iodomethyl)silatranes with methyl substituents in β-position relative to the nitrogen atom

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Crystal and molecular structure of 1-(iodmethyl)- and 1-(iodpropyl)silatranes

The crystal and molecular structures of 1-(iodmethyl)silatrane and 1-(iodpropyl)silatrane are determined by X-ray diffraction. The effect of the iodine heteroatom upon silatrane moieties of the molecules through oneand three-carbon chains is studied based on the geometric characteristics of the molecules and the analysis of their packings.     

On the viscosity of Fe<Subscript>79</Subscript>Cr<Subscript>21</Subscript> melt of congruent composition

The temperature and time dependences of the Fe₇₉Cr₂₁ melt viscosity have been investigated by the method of damping torsional vibrations of a crucible with one or two face surfaces. Anomalies in the viscosity polytherms at certain temperatures have been found for the first time. The display of these anomalies is determined by the melt structure and the melt-crucible interaction.     

Solvatochromism of heteroaromatic compounds: XXX. <Emphasis Type="Italic">N</Emphasis>-Methyltrifluoromethanesulfonamide as hydrogen-bond donor

In two-centered H-complexes with protophilic solvents, the monomer of N-methyltrifluoromethanesulfonamide I behaves as a strong H-bond donor, stronger than 4-fluorophenol and ranking second after 4-nitrophenol. In protophilic media, amide I exists as monomeric H-complexes with a two-centered H-bond and 1:2 H-complexes of the open-chair dimer with a bifurcated (three-centered) hydrogen bond. The formation of a strong bifurcated H-bond weaken the bridging N-H.‥O=S bond.     

Structure of Barbituratobis(2,2'-Dipyridyl)copper(II) Heptahydrate

Russian Journal of Coordination Chemistry - The structure of the complex [Cu(Bipy)2(BA)] ? 7H2O (I), where Bipy is 2,2'-dipyridyl, and BA2– is the barbituric acid anion (H2BA), is...