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Bimetallic alloys are considered to be a promising type of catalysts with improved activity and selectivity that are distinct from those of the corresponding pure nanoclusters [1-4]. Using first principles density functional calculations, we study the structures and energies of Al_nPt bimetallic clusters up to 13 atoms. If platinum, nickel, and other transition metal catalysts are particularly important in the catalysis of hydrogen, hydrogen adsorption on a metal surface is an important step in the catalytic reaction. Because of large exothermic energy changes and relatively small activation energies, Al₇Pt and Al₁₂Pt could serve as highly efficient and low-cost catalysts for the hydrogen dissociation. To clarify this assumption and achieve a good understanding, the H₂ adsorption and dissociation over bimetallic AlPt clusters are systematically investigated in our work.

The conformational properties of a dansyl amide molecule (CH₃)₂N-C₁₀Н₆-SO₂NH₂, which is widely used for fluorescent labeling of compounds, e.g., amino acids or nucleotides and compounds able to form liquid crystals, are studied. It is found that the molecule has six conformers with relative energies 0/0.13, 1.13/1.38, 0.06/0.06, 0.31/0, 2.95/2.70, 0.31/0 (B3LYP/cc-pVTZ and МР2/cc-pVTZ methods respectively). In all conformers the naphthalene core becomes non-planar under the effect of two substituents. The effect of the nature of substituents on the geometric parameters of the conformers is considered. In terms of the NBO analysis a substantial deviation of the S-N bond in the -SO₂NH₂ substituent from orthogonality and also the asymmetrical position of the -N(СH₃)₂ group with respect to the naphthalene core are explained. The paths and barriers of conformational transformations of the dansyl amideа molecule are determined. The structure of the (CH₃)₂N-C₁₀H₆-SO₂NН-X moiety in the crystals is analyzed and the relationship between the relative energy of the conformers of a free molecule and the probability of the occurrence of their structures in the crystals is determined.

The thermal Curtius rearrangement of cinnamoyl azide, 1-azido-3-phenylprop-2-ene-1-one, and the reactions of some of its derivatives is studied theoretically using the DFT (B3LYP-631G(d, p) approach. The potential energy surface profiles of the rearrangement are calculated. The transition state was located and confirmed. The Curtius rearrangement of the studied compounds is a one-stage, discrete reaction. A weak effect of substitution on the reaction rate is due to the unique, localized p system of the studied molecules; strong opposing dipoles span the whole molecule.

The phase transitions and ionic mobility in solid solutions (SS) with the fluorite structure ((100−х)KBiF₄−xZrF₄, where х = 2.5−10 mol.%) are studied by DSC, X-ray crystallographic analysis, and ¹⁹F NMR methods. Phase transitions are determined in the solid solutions containing 10% of ZrF₄. The types of ion motions in the SS fluoride sublattice and the corresponding temperature ranges (150−570 K) are determined. A high ionic conductivity in these solid solutions (~10^-3−10^-2 S/cm in the temperature range from 475 K to 550 K) is established, this fact not excluding the possibilities to use them for the production of materials with high ion conductive properties.

We report herein the synthesis and physicochemical characterization of a new mixed-ligand iron(III) complex of the formula (C₅H₆ClN₂)[Fe(C₂O₄)₂(H₂O)₂]×2H₂O. This compound is prepared by slow evaporation at room temperature and characterized by single crystal X-ray diffraction. It is characterized by IR and UV-VIS spectra and thermal analysis (TG and DTA). In this compound, the iron ion has a slightly distorted square bipyramidal environment, coordinated by two chelating oxalate ions and two water molecules. Structural cohesion is essentially established by p-p interactions between the rings of pyridine groups and intermolecular hydrogen bonds connecting the ionic entities and uncoordinated water molecules. Magnetic susceptibility measurements exhibit the paramagnetic behavior at high temperatures. However, at low temperatures, the magnetic data show the occurrence of weak antiferromagnetic intermolecular interactions between the local spins.

Based on experimental (viscosimetric) studies, the physicochemical characteristics of solvated potassium and chlorine ions in dimethylsulfoxide-containing (DMSO) aqueous solutions are determined in the temperature range 25−40 °C. The Hartree−Fock nonempirical method (ab initio) with the (6−31+G(d,p)) basis set is used to calculate the structural and energy parameters of (K⁺,Cl⁻)/H₂O and (K⁺,Cl⁻)/(H₂O+DMSO) complexes in vacuum; the solvent effect is taken into account by the self-consistent reaction field (SCRF) method within the Onsager model. It is found that the solvation of individual ions in water−DMSO mixtures is due to the properties and structural features of the mixed solvent and the nature of the ions.

The enthalpies of dissolution of glycine in aqueous electrolyte solutions are measured by calorimetry at temperatures of 288 K, 298 K, and 313 K in the molality range from 0.25 mol/kg to 6 mol/kg NaCl and to 4.5 mol/kg KCl. The enthalpy and heat capacity parameters are determined for the pair and triple interactions of glycine with electrolyte in water. Special (singular) points are discovered on the concentration dependences of the heats of dissolution of glycine in aqueous electrolyte solutions and in urea solutions at different temperatures. At these points, such a structurally sensitive property as the entropy of dissolution is temperature independent and the partial heat capacity of glycine is equal to that of the crystalline amino acid. The position of the singular point on the concentration axis is identical for NaCl and KCl solutions; in the case of urea solutions, the singular point is achieved at a much higher concentration of urea.

The second overtone band shape of water and its temperature dependence are identical to those of melted and distilled water.

The crystal structure of a novel chained metal-organic coordination polymer [Cd(dmf)(ntca)] obtained by heating of cadmium nitrate and naphthalene-1,4,5,8-tetracarboxylic acid monoanhydride (H ₂ntca) in N,N'-dimethylformamide (DMF) is determined.

The X-ray crystallographic method is used to determine the crystal structure and characteristic features of the molecular structure of 3-(2-(2-nitrophenyl)hydrazono)-5-phenyl-3 H-furan-2-one produced by the reaction of azo coupling of 2-nitrophenyldiazonium salt with 5-phenyl-3 Н-furan-2-one.