Reaction of perfluoro ketones with hexamethyldisilazane

Conclusions Perfluoro ketones react with hexamethyldisilazane under mild conditions to give 2-trimethylsilyloxy-2-trtmethylsilylaminoperfluoropropanes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2352–2353, October, 1972.     

Structure,stability, and disproportionation mechanisms of organic interhalides of the cholinium series: an experimental and theoretical study

The stability constants of acetylcholinium, carbamoylcholinium, and cholinium diiodochlorides and diiodobromides in chloroform solutions were determined and the kinetics of disproportionation of these systems in 1 : 9 CHCl₃—MeOH (MeCN) mixtures were studied by UV spectroscopy. A possible mechanism of mutual transformations of the polyhalides is proposed and an interrelation between the nature of the iodine-coordinating solvent and the extent of reversibility of the process is established. The electronic structures and relative stabilities of acetylcholinium iodohalides and charge-transfer complexes S·XI₂ ^– and S·I₂ (S = MeOH, MeCN, CHCl₃; X = Cl, Br, I) were studied by ab initio RHF and MP2(full) methods in the HW+(3d) and 6-31G++(d,p) basis sets. It was found that all the solvents studied favor the decomposition of the iodohalide anions to liberate molecular iodine; however, disproportionation of I₂ is possible only for the S·I₂ complexes with a high extent of charge transfer.     

Linear-dendritic supramolecular complexes as nanoscale reaction vessels for "green" chemistry. Diels-Alder reactions between fullerene C60 and polycyclic aromatic hydrocarbons in aqueous medium

This study describes the first Diels-Alder (DA) reaction performed in aqueous medium with highly hydrophobic compounds-fullerene (C 60) as the dienophile and anthracene (An) or tetracene (Tet) as the dienes, respectively. The reactions are performed in nanocontainers, constructed by self-assembly of linear-dendritic amphiphilic copolymers with poly(ethylene glycol), PEG or poly(ethylene oxide), PEO as the hydrophilic blocks and poly(benzyl ether) monodendrons as the hydrophobic fragments: G3PEO13k, dG3 and dG2. Comparative studies under identical conditions are carried out with an amphiphilic linear-linear copolymer, poly(styrene)1800- block-PEO2100, PSt-PEO, and the nonionic surfactant Igepal CO-720, IP720. The binding affinity of supermolecules built of these amphiphiles toward the DA reagents decreases in the following order: G3PEO13k > dG3 > PSt-PEO > dG2 > IP720. The kinetic constant of binding is evaluated for tetracene and decreases in a similar fashion: 5 x 10 (-7) M/min (G3PEO13k), through 4 x 10 (-7) M/min (PSt-PEO) down to 1.5 x 10 (-7) M/min for IP720. The mobility of substrates encapsulated in the micellar core, estimated by pyrene fluorescence decay, is 95-121 ns for the micelles of the linear-dendritic copolymers and notably higher for PSt-PEO (152 ns), revealing the much denser interior of the linear analogue. The apparent kinetic constant for the DA reaction of C 60 and Tet within the G3PEO13k supermolecule in aqueous medium is markedly higher than in organic solvent (toluene), 208 vs 1.82 M /min. With G3PEO13k the conversions reach 49% for the DA reaction between C 60 and An, and 55% for C 60 and Tet. Besides the monoadduct (26.5% yield) the reaction with An produces exclusively increasing amounts of D 2 h -symmetric antipodal bis-adduct, whose yield reaches up to 22.5% after 48 h. In addition to the environmentally friendly conditions notable advantages of the synthetic strategy described are the extended stability of the linear-dendritic nanovessels, the easy collection of the products formed, and the recovery and reuse of unreacted reagents and linear-dendritic copolymers.     

Crystal growth of β-Phthalocyanines from the vapour phase in closed ampoules

An influence of temperature gradient, inert gas pressure and pulling rate on the growth parameters of β-phthalocyanine single crystals grown in the closed ampoules is investigated. The morphology and structure — sensitive properties of β-CuPc crystals grown under different conditions are compared.     

Fluorinated heterocumulenes

Conclusions Cycloaddition of perfluoroisobutylene to the C=N bond of bistrifluoromethylketenimines takes place in the presence of nucleophilic catalysts.For communication 13, see [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, Vol.8, pp. 1813–1817, August, 1976.     

Short path to the synthesis of bi- and tricyclic compounds containing the 3-oxabicyclo[3.3.0]octene fragment from conjugated enynes by successive AdE reaction and [2+2+1]-cycloaddition

Conclusions A short general scheme was developed for the synthesis of a series of bi- and tricyclic compounds containing a 3-oxa-bicyclo[3.3.0]octane fragment on the basis of the successive acylallyloxylation of the double bond in the hexacarbonyldicobalt complexes of conjugated enynes and subsequent intramolecular [2+2+1]-cycloaddition.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 334–344, February, 1989.     

β, β-Bis(trifluoromethyl)glycidic ester

Conclusions ,-Bis(trifluoromethyl)glycidic ester is far more active than ,-dimethylglycidic ester and is opened by amines on the side of the -carbon atom.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8 pp. 1529–1530, August, 1964     

Crystal and Molecular Structures of 3-Carboxypropyltriphenylphosphonium Diiodobromide

Complexation in the 3-carboxypropyltriphenylphosphonium bromide–molecular iodine system in chloroform was studied. The maximum number of iodine molecules coordinated by 3-carboxypropyltriphenylphosphonium bromide was established by the spectrophotometric method using a function of the average-iodine number, and the stability constant of the complex was determined. The [(C₆H₅)₃P(CH₂)₃COOH]BrI₂ diiodobromide was studied by X-ray diffraction analysis. The characteristic feature of the crystalline salt was the formation of dimer associates: anionic associates were formed due to the Br···Br intermolecular interactions and cationic associates were formed due to the O···H–O hydrogen bonds. The data obtained were correlated to the results of quantum-chemical calculations.