The rotational mobility of fulleropyrrolineoxyl in toluene solution

The rotational mobility of a stable fullerene-based nitroxyl radical (fulleropyrrolineoxyl) in toluene was studied. The rotational correlation time of fulleropyrrolineoxyl was found to be about eight times longer than that of 4-oxy-2,2,6,6-tetramethylpiperidine-1-oxyl. The activation energy of the rotational motion of both probes was determined and their hydrodynamic radii estimated.     

Thermodynamic parameters of intermolecular interaction in strongly associated solvents and their mixtures with dimethylformamide

The specific and nonspecific constituents of the total energy of intermolecular interasction in ethylene glycol, diethylene glycol, and formamide were determined for the range 288.15–323.15 K using a simulation approach. Diethylene glycol, like formamide and ethylene glycol, forms networks of hydrogen bonds. In ethylene glycol and formamide, the hydrogen bonds make a predominant contribution to the total interaction energy. The specific and nonspecific contributions in mixtures of the above solvents with dimethyl-formamide were calculated, and the results were discussed in combination with the data for aqueous dimethyl-formamide solutions.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 11, 2004, pp. 1789–1796.Original Russian Text Copyright © 2004 by Zaichikov, KrestyaninovThis revised version was published online in April 2005 with a corrected cover date.     

Thermochemical aspects of interaction of polyimide composites with organic sorbents

Interaction of ITA-31 polyimide binder with a series of industrial sorbents based on styrene and vinylpyridine derivatives was studied.     

Use of potassium permanganate as a possible kinetic standard in thermal analysis

Analysis of the mechanism of congruent dissociative evaporation of solid substances led to a suggestion that potassium permanganate can be used as a possible kinetic standard in thermal analysis.     

Formation of thin carbon films containing metal nanoparticles by thermolysis of a polymer precursor

A new procedure was developed for preparing carbon films with magnetic metal nanoparticles by thermolysis of a polymer precursor. The conditions for preparing carbon films with required surface concentration of the metal nanoparticles and hence with dielectric or metallic properties were determined.     

Studies on indian medicinal plants-XLIV: Solanoforthine,a new steroidal alkaloid from solanum seaforthianum. a note on the mass spectrum of solanocapsine

The structure of solanoforthine, m.p. 208–10°, [α]_D- 26.6°, a new steroidal alkaloid isolated from Solanum seaforthianum Andr., has been established as 3β-amino-22,26-epimino-16α,23-epoxy-22αH,25βH-cholest- 5- en -23β - ol 3, based on chemical and spectroscopic evidence and by its reduction to solanocapsine 2, another steroidal alkaloid encountered in the same species. The mass spectra of2 and 3 are discussed.     

Enantioselective synthesis of functionalized γ-butyrolactones

Sharpless asymmetric dihydroxylation and aminohydroxylation of (E)-dimethyl-2-alkylidene glutarates 2 were shown to afford enantio-enriched or enantiopure highly functionalized γ-butyrolactones 3 and 7.     

Defect magnesium oxides containing acetate and nitrate ion fragments incorporated in the oxide structure

The results of studies on the synthesis of defect magnesium oxides by MgO hydration in salt solutions are summarized. The incorporation of oxygen-containing salt anions into the anionic hydroxide/oxide framework is described. In this case, the anion residue whose oxygen atoms belong to the oxygen framework of the oxide is incorporated in the octahedral oxygen cell of the oxide to occupy the place of a virtual magnesium cation. A portion of cationic vacancies remains free, whereas a portion is occupied by the transformed anion residue with a positive charge other than 2+. As a result, defect magnesium oxides are formed as substitutional solid solutions. The structure and charge heterogeneity of defect oxides is responsible for their high catalytic activity.     

Hydrogen peroxide formation in the oxidation of carbonyl-containing compounds at β-CH bonds

The concepts of the selective inhibition of reactions with the participation of HO ₂^· radicals by nitrobenzene in accordance with a cyclic mechanism were supported using cyclohexanol oxidation as an example. It was demonstrated that the nitroxyl radical generated from nitrobenzene selectively reacts with HO₂ ^· to form hydrogen peroxide and nitrobenzene. A decrease in the rates of oxidation of esters, carboxylic acids, and ketones with specially chosen structures in the presence of nitrobenzene, as well as the detection of H₂O₂ and corresponding ,-unsaturated compounds among the reaction products, indicated that the degradation of -peroxyl radicals of the above compounds occurred under conditions of the liquid-phase oxidation of organic substances that result in the formation of the HO₂^· radical and an unsaturated compound.Translated from Kinetika i Kataliz, Vol. 45, No. 6, 2004, pp. 814–820.Original Russian Text Copyright © 2004 by Nepomnyashchikh, Nosacheva, Perkel.     

Single nanocrystal arrays on patterned poly(ethylene glycol) copolymer microstructures using selective wetting and drying

Single nanocrystal arrays were fabricated on sub-microwells of poly(ethylene glycol) (PEG) copolymer using selective wetting on the hydrophilic regions of the exposed substrate surface and subsequent drying. Templates were produced by molding a thin film of a PEG-based random copolymer on hydrophilic substrates such as glass or silicon dioxide. The polymeric microstructures provide a topographical barrier around the well, which makes it possible to create nanocrystal arrays with controlled geometrical features. The size of the nanocrystal was found to decrease with decreasing well size and also decrease with decreasing topological height. A simple empirical equation was derived to predict the size of the crystal as a function of the pattern size and height, which is in good agreement with the experimental data.