Stereochemistry of seven-membered heterocycles 5. The conformation of 1.3-dioxacyclohept-5-enes

1. According, to the results of dipole moment and IR and Raman spectroscopy methods, the butenediol acetal's (I)-(IX) are characterized by a conformational equilibrium of the chair and twist forms determined by the influence of various factors. 2. In the determination of the conformational equilibrium of the 2-alkyl-substituted acetals the influence of the "alkyl" dipole must be taken into account. © 1981 Plenum Publishing Corporation

Hydrogen bonds formed by methyl groups of acetonitrile: Infrared and calorimetric study

Solutions of acetonitrile (I) in tetrachloromethane and deuteratred solvents (S) (benzene, acctonitrile, acetone and dimethylsulphoxide) have been studied by IR absorption spectra. The observed solvent effect on the IR spectrum of I was explained in terms of the existence of complexes with hydrogen bonding of the type NCCH3...solvent (S). The strength of the hydrogen bonding was characterized by enthalpies of specific interactions of I with solvents ΔHI/S int(sp). The values ΔHI/S int(sp) were determined both by IR spectroscopy and calorimetry and were found to be within the range 0.3-1.5 kcal mol-1. © 1993

Investigation of Borosilicate Glasses with Simulated HLW Components and Determination of Their Chemical Durability

Received: 25.11.2020. Revised: 02.03.2021. Accepted: 03.03.2021. Available online: 04.03.2021.This article belongs to the PCEE-2020 Special Issue.The paper discusses the current status of the HLW vitrification technology applied at the radiochemical plant of the Mayak PA. Conceptual and technical solutions proposed to develop the technology of vitrification of various types of liquid HLW at the Mayak PA are presented. Compositions of borosilicate glasses with HLW components are described, temperatures of their melting and easy pouring are determined. Chemical durability parameters obtained for the borosilicate glasses are provided

Stereochemistry of seven-membered heterocycles. 3. Conformation of 5,6-dichloro-1,3-dioxacyclopent-5-enes and the planar-fragment effect

1. It is shown by dipole-moment measurements and IR and PMR spectroscopy that 2-R-5,6-dichloro-1, 3-dioxacyclohept-5-enes (R=C6H5, p-ClC6H4, p-NO2C6H4 and the corresponding cyclohexanone ketal exist in the flexible form; the 2-t-butyl analog exists in a chair-e-twist equilibrium depending on the polarity of the medium. 2. It is shown that a conformational planar-fragment effect occurs as a result of shielding of the C-Cl and C-H bonds in the chair form. © 1981 Plenum Publishing Corporation

Low-temperature conductivity of quasi-one-dimensional conductors: Luttinger liquid stabilized by impurities

A new non-Fermi-liquid state of quasi-one-dimensional conductors is suggested in which electronic system exists in a form of collection of bounded Luttinger liquids stabilized by impurities. This state is shown to be stable towards interchain electron hopping at low temperatures. Electronic spectrum of the system contains zero modes and collective excitations of the bounded Luttinger liquids in the segments between impurities. Zero modes give rise to randomly distributed localized electronic levels, and long-range interaction generates the Coulomb gap in the density of states at the Fermi energy. Mechanism of conductivity at low temperatures is phonon-assisted hopping via zero-mode states. At higher voltages the excitations of Luttinger liquid are involved in electron transport, and conductivity obeys power-law dependence on voltage. The results provide a qualitative explanation for recent experimental data for NbSe3 and TaS3 crystals.Comment: 12 pages, 1 figur

Stereochemistry of seven-membered heterocycles 5. The conformation of 1.3-dioxacyclohept-5-enes

1. According, to the results of dipole moment and IR and Raman spectroscopy methods, the butenediol acetal's (I)-(IX) are characterized by a conformational equilibrium of the chair and twist forms determined by the influence of various factors. 2. In the determination of the conformational equilibrium of the 2-alkyl-substituted acetals the influence of the "alkyl" dipole must be taken into account. © 1981 Plenum Publishing Corporation

Stereochemistry of seven-membered heterocycles 5. The conformation of 1.3-dioxacyclohept-5-enes

1. According, to the results of dipole moment and IR and Raman spectroscopy methods, the butenediol acetal's (I)-(IX) are characterized by a conformational equilibrium of the chair and twist forms determined by the influence of various factors. 2. In the determination of the conformational equilibrium of the 2-alkyl-substituted acetals the influence of the "alkyl" dipole must be taken into account. © 1981 Plenum Publishing Corporation

Stereochemistry of seven-membered heterocycles 5. The conformation of 1.3-dioxacyclohept-5-enes

1. According, to the results of dipole moment and IR and Raman spectroscopy methods, the butenediol acetal's (I)-(IX) are characterized by a conformational equilibrium of the chair and twist forms determined by the influence of various factors. 2. In the determination of the conformational equilibrium of the 2-alkyl-substituted acetals the influence of the "alkyl" dipole must be taken into account. © 1981 Plenum Publishing Corporation

Hydrogen bonds formed by methyl groups of acetonitrile: Infrared and calorimetric study

Solutions of acetonitrile (I) in tetrachloromethane and deuteratred solvents (S) (benzene, acctonitrile, acetone and dimethylsulphoxide) have been studied by IR absorption spectra. The observed solvent effect on the IR spectrum of I was explained in terms of the existence of complexes with hydrogen bonding of the type NCCH3...solvent (S). The strength of the hydrogen bonding was characterized by enthalpies of specific interactions of I with solvents ΔHI/S int(sp). The values ΔHI/S int(sp) were determined both by IR spectroscopy and calorimetry and were found to be within the range 0.3-1.5 kcal mol-1. © 1993

Hydrogen bonds formed by methyl groups of acetonitrile: Infrared and calorimetric study

Solutions of acetonitrile (I) in tetrachloromethane and deuteratred solvents (S) (benzene, acctonitrile, acetone and dimethylsulphoxide) have been studied by IR absorption spectra. The observed solvent effect on the IR spectrum of I was explained in terms of the existence of complexes with hydrogen bonding of the type NCCH3...solvent (S). The strength of the hydrogen bonding was characterized by enthalpies of specific interactions of I with solvents ΔHI/S int(sp). The values ΔHI/S int(sp) were determined both by IR spectroscopy and calorimetry and were found to be within the range 0.3-1.5 kcal mol-1. © 1993