Vol 476, No 2 (2017)

Spectral properties of inclusion complexes of cucurbit[7]uril (CB[7]) with styryl dye dications containing N-ammonioalkyl substituents of various length (D1, D2, D3) in water have been studied. The optimized structures of these complexes calculated by DFT methods made it possible to correlate the observed effects with the position of the nitrogen atom of the pyridinum residue of styryl dyes with respect to the CB[7] cavity. The bathochromic shifts of long-wavelength absorption bands for the inclusion complexes of D1 and D2 and the absence of such a shift for D3 are caused by structural distinctions between the inclusion complexes.

The short-time polymerization of butadiene induced by heterogeneous titanium catalysts was studied for the first time. In the 0.1−0.3 s time interval, polymerization is characterized by a considerable decrease in the chain propagation rate constant and 1,4-stereospecificity of the catalysts. A structure kinetic continuum model was proposed in which the initiation step and the first propagation steps are kinetically continuous. The violation of this continuity changes the catalyst stereospecificity and creates conditions for chain transfer reactions.

Treatment of single-walled carbon nanotubes (SWCNT) in a gaseous 40%NH₃–1%С₂Н₂–C₂H₄ mixture at 600 and 700°С led to “nitrogen-containing carbon coating–single-wall carbon nanotubes” composites. Single-walled carbon nanotubes after etching in aqua regia (SWCNTetch) and doped with nitrogen (N-SWCNT) were studied by XPS, electron microscopy, and IR spectroscopy. It was found that the initial SWCNTetch surface contains various oxygen-containing functional groups. Treatment of SWCNTetch in a 40%NH₃–1%С₂Н₂–C2H₄ mixture led to the formation of a thin carbon coating on the carbon nanotube surface due to polymerization and condensation of hydrocarbons. After treatment at 600°C, the formation of nitrogen-containing functional groups is insignificant; however, when the treatment temperature is increased to 700°C, the nitrogen content reaches 0.5 at % of the weight of the N-SWCNT sample.

A method to produce a technically suitable, hard-magnetic material of composition Fe–26% Cr–16% Co–2% Mo–2% W from a powder raw material was proposed. A distinguishing feature of the method is a reduced temperature of sintering of powder compacts (1200°C). The sintered samples are subjected to hot rolling. The magnetic and strength characteristics of the thus obtained magnetic material are on the level of those of alloys produced by powder metallurgy at a sintering temperature of about 1400°C and their cast analogs. Data on the magnetic hysteresis and strength properties of the synthesized material were presented.