The synthesis of spirane and bicyclic thiolanes from homoallylic thiols

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2155–2156, September, 1989.     

New integral equation for the calculation of the structure and properties of dense liquids

Journal of Structural Chemistry - The modification of the relationship between the direct correlation function c(r) and the potential Φ(r) and the complete correlation function h(r), which has...     

5－（4－乙酰氧基苯基），10，15，20－三苯基卟啉金属配合物修饰的铂支撑双层脂膜的IV性质

合成并表征了５－（４－乙酰氧基苯基），１０，１５，２０－三苯基卟啉及其金属配合物，将它们作为修饰物，制得铂支撑的双层脂膜，用循环伏安法研究了抗坏血酸的氧化还原反应，并对其机理作了探讨。     

Fluctuation-Optical Method for Determining Gelation Point of Biopolymer Systems

Method for determining temperature of the transition of biopolymer systems to gellike state was developed using the earlier discovered effect of decaying amplitude of spontaneous fluctuations of system optical density, which significantly exceed the level of intrinsic noise of measuring devices of Specord M40 and Specord M400 spectrophotometers. These fluctuations are caused by the thermal convection resulting in the emergence of randomly distributed regions with different optical properties in the analyzed systems. The inhomogeneity can by amplified by the fraction of supermolecular particles (SMP). The effect of convection markedly decreases as a result of the loss of fluidity during the system gelation, thus underlying the instrumental registration of the sol–gel transition whose efficiency was confirmed in this work using aqueous preparations of plant polysaccharides (pectin, agar, furcellaran, and -carrageenan). It was shown that, in the cases of initially optically homogeneous systems, the role of the SMPs can be played (if necessary) by the relatively small amounts of the particles of chemically inert compounds (for example, cellulose) at slight mixing of a system using magnetic stirrer. This method was applied for constructing the fragment of the phase diagram of the furcellaran–water system during its cooling. The interpretation of its semi-logarithmic transformation in terms of the Eldridge–Ferry theory resulted in the estimation of the amount of heat evolved during the formation of gel network junctions (presumably, due to the pair associations of double helixes), which appeared to be equal to –63 kJ mol^–1.     

The electron-probe method in the study of polymers

Physical principles are given for the method, which employs changes in the absorption and luminescence spectra of trace components in research on the structural and phase transitions in the polymer matrix. The scope of the method is demonstrated for polyethylene as matrix (a typical two-phase system), with anthracene as the probe. The spectrum shifts about 750 cm^–1 to longer wavelengths in the crystalline phase relative to the amorphous phase. Such shifts are very sensitive to temperature and to mechanical damage to the polyethylene, so it is possible to follow temperature trends in the densities of the amorphous and crystalline regions; the bulk expansion coefficients can be measured, as can the vitrification temperature. It can be shown that the melt (50 above the melting point) contains crystalline regions of fluctuation type.Tests on cold drawing of polyethylene reveal melting (recrystallization) of the supermolecular structure in the neck region, in accordance with Kargin's views. The method is thus applicable to second-order phase transitions.Anthracene in the crystalline regions shows a considerable enhancement of the luminescence intensity, evidently from migration of energy from molecules in the amorphous material.