Obtaining partial widths from siegert wavefunctions

It is shown that a simple expression for the partial widths in a multichannel decay problem can be readily obtained from a Siegert wavefunction.     

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...     

Multiparametric curve fitting-I Computer-assisted evaluation of chelatometric titrations with metallochromic indicators

A curve-fitting procedure has been developed for the photometric complex-formation titration of the metal-indicator complex MIn(N) which is assumed to predominate in solution. By means of a least-squares procedure the following five parameters were determined: the end-point, the absorbance of the indicator complex A(M)XXX. the indicator concentration CXXX, the stability constants and, if possible, k(MY) . A modified version of Sillen's Letagrop Vrid has been used for the mathematical-statistical approach of the non-linear model based upon the non-transformed function A = f(v). Additional information is obtained about the goodness of fit, indicating whether the chosen model with predominance of MIn(N) is correct or not. The use of the program is demonstrated by application to chelatometric microtitrations of zinc and lead with EDTA, using Naphthylazoxine 6S and SNAZOXS as metallochromic indicators.     

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 application of C-N.M.R. spectroscopy to the determination of the stereochemistry of Diels-Alder adducts

Long-range (³J) ¹³C-H coupling is a reliable probe to evaluate the stereochemistry of cycloaddition products. The method is best applied to carbonyl containing adducts but not restricted to them. Several structures have been revised and new ones evaluated.     

Synthesis of 2-aryloxy-4,6-bis(4-carboxyphenyl)-sym-triazines and their chlorides

The peculiarities of the reaction of some substituted (in the benzene ring) 2,4-dichloro-6-aryloxy-sym-triazines with toluene under the conditions of the Friedel-Crafts reaction were investigated. Methods for the synthesis of 2-arloxy-4,6-bis(4-carboxyphenyl)-sym-triazines and their chlorides were developed. Cleavage of the ether bond to give a dihydro-sym-triazine structure occurs in the case of 2,4-dichloro-6-benzyloxy-sym-triazine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1125–1129, August, 1983     

Derivatives of Methyl N-[5(6)-(4-Aminophenylsulfanyl)benzimidazol-2-yl]carbamate and Phthalic Anhydrides. Synthesis and Biological Properties

Products of the reactions methyl N-[5(6)-(4-aminophenylsulfanyl)benzimidazol-2-yl]carbamate with phthalic anhydrides, involving the aniline nitrogen atoms, were obtained. Biological properties (embryotoxicity and toxicity) of the products and their mixtures with phase-transfer catalysts were studied. On this basis, new antihelminthic agents were developed.     

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.