Influence of cobalt(III) dimethyldithiocarbamate complexes on styrene polymerization initiated by tert-butyl perbenzoate

Kinetic features of radical polymerization of styrene initiated by tert-butyl perbenzoate in the presence of tris(N,N-dimethyldithiocarbamato)cobalt(III) (CoL₃) and its adduct with iodine (CoL₃ · 2I₂) were studied. The optimal concentration ratios of the activators and tert-butyl perbenzoate, providing fast styrene polymerization at 338–368 K, were determined.     

O predstavlenii lineinykh operatorov, perestanovochnykh s operatorom umnozheniya

Summary Pust' E_j (j =1,2) - lokal'no vypuklye prostranstva funktsii, odnoznachnykh i lokal'no analiticheskikh na nekotorom mnozhestve Q ⊂ℂ. Pust', dalee, m(E₁,E₂) - mnozhestvo vsekh mul'tiplikatorov pary E₁, E₂ i L (E₁, E₂) sovokupnost' vsekh lineinykh operatorov, deistvuyushchikh iz E₁ v E₂. V stat'e e pri opredelennykh predpolozheniyakh poluchen kriterii predstavleniya operatora T iz L (E₁, E₂), kommutiruyushchego s fiksirovannym elementom a∊ m(E₁,E₁) ∩m(E₂,E₂), v kanonicheskoi forme Ty = b · y, gde b∊m(E₁,E₂). Obsuzhdayut·sya predpolozheniya, pri kotorykh poluchen kriterii, i privodyat·sya primery, pokazyvayushchie ikh sushchestvennost'.     

Multipliers of convergence in norm of series with respect to multiplicative systems

We prove analogs of the Telyakovskii-Pochuev criteria for multipliers of uniform convergence and of convergence in the integral metric for multiplicative systems with bounded generating sequence.     

Novel photoswitching dithienylethenes with ferrocene units

Two novel dithienylethenes with ferrocene units were synthesized by Wittig reaction. The structure of 2a has been established by X‐ray diffraction studies. They could reversibly interconvert between two thermally stable forms, an open and a closed one, using light of different wavelengths as triggers. Copyright © 2006 John Wiley & Sons, Ltd.     

Effect of electric current on the magnetic and magnetoelastic properties of amorphous ferromagnetic alloys

The magnetic and magnetoelastic parameters of Fe₆₄Co₂₁B₁₅ and Fe_81.5B_13.5Si₃C₂ amorphous ferromagnetic alloys treated by direct electric current in air are studied as functions of the applied magnetic field and current density. The samples of the alloy have the form of narrow strips with different lengths. It is found that the magnetoelastic parameters of the dc-treated alloys depend on the magnetic field in a qualitatively different way. From the behavior of the magnetic and magnetoelastic parameters of the alloys in the magnetic field a model of magnetization nonuniform distribution in amorphous ferromagnetic alloys subjected to dc treatment is proposed.     

Direct atomic-absorption determination of the Ni and V content in oil

A direct (without sample pretreatment) atomic-absorption method of V and Ni determination in oil with electrothermal atomization and Zeeman correction of background was developed.     

Preparation and study of properties of sulfonic acid ion exchangers based on polypropylene fibrous material

The possibility of raising the static exchange capacity of strongly acidic ion-exchange materials produced by grafting of styrene onto polypropylene fibers, with the subsequent sulfonation of the products synthesized, was analyzed. The chemical and osmotic stabilities of the sulfonic cation exchangers obtained and their frost resistance in freeze-thaw cycles were studied.     

Stereochemistry of seven-membered heterocycles: XLV. Highly diastereoselective addition of dimethyl 1,2,4,5-tetrazine-3,6-dicarboxylate to 2-substituted 1,3-dithiacyclohept-5-enes

Conformationally heterogeneous 2-substituted 1,3-dithiacyclohept-5-enes (R = Ph, Me, t-Bu), which exist in solution as chair and boat conformers, react with dimethyl 1,2,4,5-tetrazine-3,6-dicarboxylate with high exo-diastereoselectivity: only the chair conformer is involved. The steric structure of 4-methyl-3,5-dithia-9,10-diazabicyclo[5.4.0]undeca-7,10-diene was determined by X-ray analysis. Its crystal packing and supramolecular structure were also analyzed.     

Oxidation of prochiral sulfides with chiral dioxirane

Dioxirane generated in situ by reaction of chiral 1,2:4,5-di-O-isopropylidene-D-erythro-hexo-2,4-diulo-2,6-pyranose with Oxone oxidizes prochiral sulfides to the corresponding sulfoxides with an enantiomeric excess of 2 to 25%.