Vol 52, No 3 (2018)

The sputtering of an aqueous solution of sodium chloride with a concentration of 0.5 mol/L under bombardment by 1–20 positive ions with initial energies of 50–500 eV has been simulated by a molecular dynamics method. It has been found that the transfer of solute cations and anions to a gas phase requires a threshold energy of bombardment. It has been shown that the solute components occurred in the gas phase both as hydrated ions and in the form of ion pairs in the composition of water clusters. As the energy input into the cell reached ~0.33 eV/particle, the clusters of five or more water molecules were predominantly sputtered.

The applicability of the pyrene@2β-cyclodextrin complex as a fluorescent chemosensor for aromatic amino acids has been studied by fluorescence spectroscopy. For the first time, it has been that the sensitivity of the complex to the implementation of D-enantiomers into its cavity is higher in comparison with the L-enantiomers of aromatic amino acids. Quantum-chemical calculations confirmed that the binding of the D-enantiomers of aromatic amino acids with P@2βCD is characterized by a greater energy of complexation in comparison with the L-enantiomers.

The photooxidation of amines with triplet nitromethane has been studied using the uB3LYP/6-311g* method. The activation energies for hydrogen atom abstraction from ammonia and the amino group of methylamine or aniline have been found to be 14.1, 4.9, and 6.3 kJ mol⁻¹, respectively. Details of the hydrogen atom transfer mechanism have been studied, the structures of transition complexes have been revealed, and noncovalent interaction energies have been evaluated in terms of the theory of atoms in molecules.

Photocoloration and complexation reactions of pyridine-containing nitrosubstituted spiropyran with terbium, zinc, and lanthanum cations in acetonitrile have been studied using laser kinetic spectroscopy. The triplet state participates in the photocoloration reaction of spiropyran. The complexation reaction is accompanied by a hypsochromic shift of the absorption band and proceeds in the microsecond range with pseudo-first order rate constants of 1.4 × 10⁶, 2.3 × 10⁶, and 3.5 × 10⁵ s^–1 for lanthanum, zinc, and terbium cations, respectively.

The effect of OMe and NO₂ substituents in the phenol ring of hydroxytetraphenylimidazole (HTPI) derivatives on their luminescence in solutions and in the solid phase has been studied. The presence of the nitro group leads to multiple luminescence. In addition to the band of the photoproduct of intramolecular proton transfer, which is single for unsubstituted HTPI, nitrosubstituted imidazoles additionally have emission bands at shorter and longer wavelengths. The ratio between the bands depends on the solvent, concentration, and excitation wavelength. In solutions and polymer media, it is possible to switch luminescence by changing the excitation wavelength, and under certain conditions, white light emission is observed.

The molecular–topological structure of a tetrafluoroethylene copolymer with ethylene after γ-irradiation and thermal annealing has been studied. The pseudo-network structure of the copolymer contains, in addition to the amorphous block, crystalline segments of macromolecules in the role of branching sites. Topologically, the diblock structure of the copolymer after thermal annealing at 538 K is transformed into a three-block structure with the appearance of a high-temperature amorphous block. Irradiation of the copolymer with γ-rays to a dose of 150 kGy does not lead to appreciable changes in its molecular–topological structure.

Microwave discharges in liquids represent a new direction in plasma physics and chemistry. Results of experiments on the recovery of metals from a liquid residue after vacuum distillation of the hydroconversion product of vacuum tower bottoms by treating the residue with microwave discharge initiated in its bulk at atmospheric pressure are presented. It has been found for the first time that the concentrations of Al, Co, Cu, Fe, Mo, Ni, V, and Zn metals in a treelike structure deposited on a microwave antenna are 10–20 times their concentrations in the substrate.