Solvatochromism of Heteroaromatic Compounds: X. 2-Phenylpyrrolide Anion

2-Phenylpyrrolide anion was obtained in high-polarity media containing MeONa as an ionizing agent. The bathochromic shift of the long-wave absorption band in going from the neutral to deprotonated form is explained by the difference in the molecular orbital characteristics of the parent molecule and the anion, as well as the by change in the equilibrium conformation on deprotonation. According to ab initio calculations, the conformational rearrangement contributes partly to the observed shift; the greatest contribution is from the destabilization of the highest occupied molecular orbital.     

Solvatochromism of Heteroaromatic Compounds: XI. 1-Ethyl-2-formylbenzimidazole

Two regression dependences of the energy of the intramolecular charge-transfer transition in 1-ethyl-2-formylbenzimidazole on the polarity and polarizability of the medium have been established; one relates to the syn-periplanar conformer and the other, to the anti-periplanar conformer. The different solvatochromism of the two molecular forms is associated with the different sensitivity of low-energy electronic transitions of these conformers to nonspecific solvation.     

Determination of an optimal modifier for albumin for medicobiological technology by the X-ray photoelectron spectroscopy method

The interatomic interaction of albumin and a modifier is studied with the use of the X-ray photoelectron spectroscopy method. As the result of the study of the albumin nanomodification, an optimal modifier for albumin is determined. It is shown that the compatibility of bio- and nanostructures depends on their dimension. The modification of albumin with carbon copper-containing nanotubes leads to the albumin thermal stability up to the temperatures in the range of 525–537 K. However, the modification of albumin with carbon nickel-containing nanotubes, the radius of which is much smaller than that of carbon copper-containing nanotubes, leads to the destruction of albumin at room temperature. The dependence of the thermal stability of protein modified with vinyl pyrrolidone acrolein diacetal copolymer on its content in the mixture is found. The growth of the temperature of stabilization with the increasing content of vinyl pyrrolidone acrolein diacetal copolymer is shown.     

Role of electronic effects in forming the structure of the nitrilotrismethylenephosphonic complexes of 3<Emphasis Type="Italic">d</Emphasis> elements (Cr–Zn)

Two series of nitrilotrismethylenephosphonic complexes of 3d elements, [MII(H₂O)₃{NH(CH₂PO₃H)₃}]_n (M = Cr–Zn) and Na₈[MII{N(CH₂PO₃)₃}]₂ nH₂O (M = Co–Zn), are studied. A comparative analysis of their structural features showed the influence the Jahn–Teller effect has on the formation of the crystal structures, reactive capacities, and anticorrosive activities of these compounds.     

Development of the method for low-temperature investigations of HTSC systems on an X-ray electron magnetic spectrometer

Peculiarities of the chemical structure of bulk polycrystalline samples of the high-temperature superconductors Bi₂Sr₂CaCu₂O₈, BiSrCaCu₂O_5.5, BiSrCaCu₃O₈, and YBa₂Cu₃O_{7 ? δ} have been investigated in detail at room and superconducting temperatures on an X-ray electron magnetic spectrometer equipped with an attachment for low-temperature studies. It is shown that covalent bonding is formed at a superconducting temperature between copper and oxygen due to Cu²⁺ ions. Due to the enhancement of the d(Cu)–p(O) hybridization of copper and oxygen electrons in the superconducting state, the d-electron density increases near E _F. The occurrence of additional peaks in the O1s and Sr3d (Ba3d) spectra after transition of the system to the superconducting state indicates changes in the nearest environment of O and Sr (Ba) atoms, in particular, the transition of Sr atoms to a higher oxidation state.     

Application of X-ray photoelectron spectroscopy for studying the molecular structure of corrosion inhibitor — Zinc complex of 1-hydroxyethylidene diphosphonic acid

The molecular structure of zinc complex of 1-hydroxyethylidene diphosphonic acid was studied by X-ray photoelectron spectroscopy. The obtained data were compared with IR absorption spectrum of the same substance to acquire new information on the molecular structure. It was shown that coordination of the phosphonate group by zinc atom retains the localization of P-O π bond, the phosphonate group does not have a third-order axis of symmetry, and Zn atom can occupy positions with different coordination. Thermal destruction of the complex is accompanied by decomposition of hetero-organic ligand with detachment of the hydrocarbon fragment along C-P bonds and formation of inorganic zinc salts.     

Jahn–Teller effect and the formation of anticorrosive protective layers of nitrilo-tris-methylene-phosphonates on surfaces of steel

Nitrilo-tris-methylene-phosphonato-three-aqua-complexes of chromium(II) and iron(II), the main components of protective layers for inhibiting steel corrosion with nitrilo-tris-methylene-phosphonates, are isolated and studied. Their ability to form protective layers is explained by their insolubility and resistance to water and air. These properties of Cr and Fe complexes are explained by Jahn–Teller distortion of the coordination environment of Cr and Fe atoms.     

Interaction between ZnHEDP corrosion inhibitor and a surface of carbon steel

The interaction between the metal-complex corrosion inhibitor ZnHEDP (a zinc complex with 1-hydroxy-ethylidene-diphosphonic acid) and a surface of 20kp steel is studied. It is shown that the chemical interaction between the corrosion inhibitor and the steel surface leads to the formation of a strong covalent bond of Zn-O-P-Fe atoms, and to Fe atoms transitioning into a high-spin state. Thermal action on the protective film results in the breaking of C-P bonds and the detachment of a carbon-containing fragment. At temperatures above 525 K, the Zn-O-(P-O)-Fe complex breaks down.     

Relaxation of the electret state of A1-(Anodic oxide film)-A1 systems

On the basis of a solution of the Debye equation we have obtained an expression that describes the relaxation of the electret potential difference U_e of A1-(anodic oxide film)-A1 systems, which is probably due to the volume electron charge formed in the field. The derived equation, which describes the relaxation of U_e in the initial stage of storage of samples, accords well with experimental results.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 109–111, July, 1991.