Effect of growth conditions on the structure of GaAs layers in the OM-hydride process

The dependence of the structure of epitaxial GaAs layers grown in the OM-hydride process on the growth temperature, the composition of the steam-gas mixture, and the preparation of the substrate surface is investigated. It is shown that the growth temperature together with the composition of the steam-gas mixture have a considerable effect on the degree of structural perfection of the epitaxial GaAs layers.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 69–71, November, 1984.     

Synthesis and properties of analogs of 5(4)-aminoimidazole-4(5)-carboxamide and purines. 14. Acylation of 5(4)-aminoimidazole derivatives

The acylation of 5(4)-aminoimidazole derivatives was studied. It is shown that acylation by means of carboxylic acid anhydrides and chlorides takes place at the amino group, whereas acylation by means of chlorocarbonic acid esters takes place at the nitrogen atoms of the imidazole ring. Methods for the selective introduction of a carbomethoxy group in the 1, 3, and 5 positions of the 5(4)-aminoimidazole-4(5)-carboxamide molecule were developed.See [1] for communication 13.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 247–252, February, 1984.     

Kinetics of Formation of Octa(<Emphasis Type="Italic">p</Emphasis>-Bromophenyl)tetraazaporphine Complexes with <Emphasis Type="Italic">N</Emphasis>-Bases in Benzene-Dimethyl Sulfoxide System

The acid-base interaction of octa(p-bromophenyl)tetraazaporphine with nitrogen-containing organic bases in benzene-DMSO system is studied. The structures of the proton-transfer complexes formed in the reaction are suggested. The reaction rate, activation parameters, and mechanism of intermolecular transfer of protons of the NH groups of octa(p-bromophenyl)tetraazaporphine to a base were shown to be determined by the nature of the proton-acceptor molecules. The dielectric permeability of a binary solvent was found to significantly affect the kinetic parameters of the process.