Kerr constants and dipole moments of aminobenzoic acids in dioxane

Aminobenzoic acids in dioxane have been investigated by dipole moment and Kerr effect methods.m-Aminobenzoic acid exists in a solution mainly (60 %) in thesyn-form. Inp-aminobenzoic acid, conjugation flattens the pyramidal configuration of the nitrogen atom, which is even more flattened ino-aminobenzoic acid owing to an intramolecular hydrogen bond.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 859–861, May, 1994.     

Steric structure and thermodynamic aspects of the complexes of dysprosium(iii) with aminobenzoic acids in aqueous solutions

Steric structures of dysprosium(III) aminobenzoate complexes with the 11 and 12 molar ratio in aqueous solutions were determined on the basis of pH-metric and paramagnetic birefringence data. An increase in conjugation observed for the series of the acids,viz., benzoic,meta-, ortho-, andpara-aminobenzoic acids, results in the increased stability of the complexes with the 11 and 12 composition. In the case ofpara-aminobenzoic acid, the polyhedra [DyL(H₂O)₆]²⁺ and [DyL₂(H₂O)₄]⁺ are cubes with the ligands coordinated to one and two edges, respectively. In the case ofmeta-aminobenzoic acid, the polyhedra [DyL(H₂O)₆]²⁺ and [DyL₂(H₂O)₄]⁺ are a dodecahedron with the ligand coordinated to one edge and a square anti-prism with the ligands coordinated to two edges, respectively. In the case ofortho-aminobenzoic acid, both the 11 and 12 complexes have structures that are intermediate between the structures ofmeta- andpara-aminobenzoic acids.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1767–1770, October, 1994.     

Specific Features of the Interaction of a Germane Molecule with Germanium Surface in Vacuum in the Presence of Hydrogen Flow

Technical Physics - The temperature dependence of the main kinetic parameters that determine the rate of pyrolysis of adsorbed germane molecules on the surface of the growing germanium layer is...     

Kerr constants and structure of benzoic acid in dioxane and CCl4

The dipole moment and Kerr effect methods showed that the dimer of benzoic acid has a conformation close to the twist form with a dihedral angle of 10°. The fraction of atomic polarization of the dimer is anomalously high (P_a 50% P_e), and it retains some polarity (DM 0.58 D).A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan' Scientific Center, Russian Academy of Sciences, 420083 Kazan'. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 5, pp. 1069–1072, May, 1992.     

Xymedone conjugate with para-aminobenzoic acid. Estimation of hepatoprotective properties

Russian Chemical Bulletin - A salt-like conjugate of xymedone with para-aminobenzoic acid in a series of pyrimidine derivatives was synthesized, and its hepatoprotective properties were studied....     

Rare-earth-cation-induced change in the cholesteric twisting of neighboring nucleic acid molecules

Certain physicochemical characteristics of particles of the cholesteric liquid-crystal dispersions of complexes of double-stranded nucleic acids with rare earth elements have been determined. It is shown for the first time that the binding of the rare earth cations to linear nucleic acid molecules ordered in the structure of particles of the cholesteric liquid crystal dispersions is accompanied not only by amplification of the abnormal band in the circular dichroism spectrum, but also by the disappearance of the characteristic maximum on the X-ray scattering curves for small angles. The (cholesteric 1-cholesteric 2) transition induced by rare earth cations is an example of the operation of a microscopic machine consisting of spatially ordered nucleic acid molecules. Particles of the cholesteric liquid crystal dispersions of nucleic acid complexes with rare earth elements hold the abnormal optical properties for a long time.     

Physicochemical Properties of Mesoporous Silicas Modified with Hydrazide and Amide Functional Groups

Physicochemical properties of mesoporous silicas modified with hydrazide and amide functional groups were studied. It was found that the main properties of the sorbents under study, characterized by pK_a1, are weakly pronounced. The replacement of the counter ion with a hydroxide occurs in a less alkaline medium, compared with monomer analogs. The sorbent modified with N', N'-dimethylhydrazide groups by the impregnation method has pK_a2 = 11.78, which is indicative of a sufficient strength of bonding between the counter ion and the silica matrix. The temperature limits, heat effects, and decomposition stages of the sorbents were determined.