Reactions of azinium cations. 7. 13C NMR spectra and electron structure of neutral σ-adducts of 1,4-diazinium cations and methylate anion

The ¹³C NMR spectra have been recorded of a number of -adducts formed by pyrazinium, quinoxalinium, and pteridinium cations with methylate anion. The experimental data were compared with CNDO/2 calculations of adduct electron structure.For Communication 6, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1385–1391, October, 1987.     

Theory of stochastic composite materials of combined structure

Institute of Mechanics, Ukrainian Academy of Sciences, Kiev. Translated from Prikladnaya Mekhanika, Vol. 29, No. 9, pp. 20–29, September, 1993.     

Multiconformational Method for Analyzing the Biological Activity of Molecular Structures

A multiconformational method for analyzing the biological activity of compounds is proposed that combines conformer search algorithms and a 3DQSAR receptor modeling procedure. The method allows one to find highactivity and lowactivity conformers and determine the receptor shape. The biological activity of a substance is determined as a superposition of the activities of its conformers with allowance for their proportions in the substance. Agreement between calculated and experimental conformations and between calculated and experimental biological activities pIC _50%) is demonstrated by the example of agonists of the 5HT_1A receptor.     

Preparative synthesis of disilane from hexaethoxydisilane and diisobutylaluminum hydride

A preparative method for the synthesis of Si₂H₆ from Si₂(OEt)₆ and (i-Bu)₂AlH is developed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 795–796, April, 1993.     

Algorithm for estimating molecular dissymmetry

A simple criterion for estimating molecular dissymmetry and an algorithm of its calculation are suggested. Calculations are performed for compounds belonging to different point groups. The new molecular characteristic may be used to predict the magnitude and sign of optical rotation. Chelyabinsk State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 3, pp. 500–506, May–June, 1998.     

Genetic Algorithm for Predicting Structures and Properties of Molecular Aggregates in Organic Substances

A genetic algorithm for predicting the structures and properties of molecular aggregates in organic substances is proposed. It has been used for modeling the most probable dimers and trimers existing in 137 organic liquids. It has been shown that the geometric and energetic features of modeled aggregates agree with known data. The energy of aggregation correlates with the enthalpy of evaporation of substances. The dependence of the energetic and geometric features of aggregates on the chemical nature of their constituent molecules is discussed.