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The molecular structure of 2-chlorobenzenesulfonyl chloride was studied by electron diffraction and quantum-chemical (МР2/6-31G**, B3LYP/6-311++G**) methods at 337(3) K. Only one (C₁) conformer was found in the gas phase. The following structural parameters were obtained: r_h1(C-H)_av = 1.105(6) Е, r_h1(C-C)_av = 1.398(3) Е, r_h1(C-S) = 1.783(11) Е, r_h1(S=O)_av = 1.427(3) Е, r_h1(S-Cl) = 2.048(4) Е, r_h1(С-Cl) = 1.731(9) Е, ∠(С-S=O1) = 109.9(8)°, ∠(С-S=O2) = 106.9(8)°, ∠(Cl1-S-O1) = 107.3(4)°, ∠(Cl1-S-O2) = 106.4(4)°, ∠C-S-Cl = 102.1(6)°, ∠O=S=O = 122.3(11)°. The C2-C1-S-Cl1 torsion angle that defines the position of the S-Cl bond relative to the plane of the benzene ring was 69.7(8)°. The B3LYP/6-311++G** calculated barriers of internal rotation of the sulfonyl chloride group were V₀₁ = 9.7 kcal/mol and V₀₂ = 3.6 kcal/mol.

The binary molybdate Li₂Zn₂(MoO₄)₃ of a new crystal type was characterized by EPR, optical spectroscopy, and X-ray diffraction methods. The crystals have the Pnma symmetry group and the lattice parameters а = 5.1139(5) Е, b = 10.4926(13) Е, c = 17.6445(22) Е; Z = 4. The crystals possess scintillation properties; emission is caused by the presence of impurity levels in the forbidden band. The EPR studies of the nature of the impurity centers responsible for the scintillation characteristics of the crystal showed that the centers were Cu²⁺ ions substituted for zinc ions in the oxygen octahedra. The directions of the main values of the g and А tensors (g_zz, A_zz) correspond to the direction of O-Cu-O of the oxygen octahedron distorted along the Z axis. The EPR spectra of the copper ions are described by the spin Hamiltonian with the parameters g_|| = 2.38, g_⊥ = 2.06; A_|| = 116 G, А_⊥ = 0 G.

A method is suggested for analyzing the model structures of crystals by calculating the spherical coordinates of the normals to the simplex faces of the simplicial Delaunay partitioning of a set of points (atoms). The normals to the simplex faces of the Delaunay partitioning of the crystal structure characterize the structure at the local level. An algorithm for constructing the invariant of the crystal structure (crystal module) was considered. Crystals modules were constructed for hexagonal and cubic ices.

A simulation of crystallization and a structural study of an overcooled NaCl melt are reported. A criterion is suggested for classifying the structural states of ions in the transition mode of nucleation. It is shown that in the bulk of overcooled liquid, short-lived crystal phase germs appear and vanish. A distribution of the critical clusters according to form and size was found. It was assumed that crystal growth occurred by collective synchronization of particle motions in crystal and liquid near the interface. The NaCl nanocrystals formed during nucleation are cubic crystals with clear-cut faces and edges. Overcooling the liquid to a greater extent led to the formation of defective polycrystalline structures.

The Kirkwood factor g_K of a model polar liquid of dipolar hard spheres (DHSs) was approximated by analytical equations using the approximation of the interaction of the second neighbors within the hindered rotation model. The derived equations describe the temperature and density dependences of the dielectric functions of the DHS liquid.

Isoentropy compressibilities of aqueous magnesium chloride and sulfate were determined based on precision measurements of ultrasound velocity, density, and isobaric heat capacity at low to high concentrations at 278.15-323.15 K. The hydration numbers h and the molar parameters of volume and compressibility were calculated based on thermodynamically correct equations for hydration complexes (V_h, β_hV_h), water in the hydration shell (V_1h, β_1hV_1h), and the void containing a stoichiometric mixture of ions (V_2h, β_2hV_2h). The h and β_hV_h values were found to be independent of the temperature; the molar compressibility of the hydration sphere (β_1hV_1h) and the stoichiometric mixture of ions without a hydration shell (β_2hV_2h) were independent of the concentration under the stated conditions. The effect of the electrostatic field of ions on the temperature dependence of the molar volume of water in the hydration sphere was more significant than the effect of pressure on the temperature dependence of the molar volume of bulk water. This is attributed to changes in the dielectric constant of water in the vicinity of the electrolyte ions.

The results of previous studies of the increments ΔG⁰_CH2, ΔH⁰_CH2, TΔS⁰_CH2 and in hydrocarbon solution processes in water, evaporation, hydration, and transfer from vapor and water to surfactant micelles are summarized. The corresponding thermodynamic cycles were constructed. A micelle was shown to be a bistable structure formed by the contact and water-separated hydrophobic interactions of the alkyl groups of surfactants. The fraction in ΔG⁰_CH2M is -2.3 kJ⋅mol^-1 for the contact associate and -0.7 kJ⋅mol^-1 for the hydrated one. Water is involved in the hydrophobic interaction of each associate. In a dualist micelle, however, ΔG⁰_CH2 = -3.0 kJ⋅mol^-1 equals that of the dispersion interaction after condensation from vapor. The dual nature of the dynamic properties of micelles is discussed.

The crystal structure of the Os₃(μ,η²-O=CC₆H₅)(η³-C₃H₅)(CO)₉ cluster synthesized by the reaction of the (μ-H)Os₃(μ-O=CC₆H₅)(CO)₁₀ complex with allylamine in chloroform was determined by X-ray analysis. Prolonged storage of the reaction mixture led to N-C bond cleavage in allylamine and η³-addition of the allyl fragment at one of the Os atoms (Os-C 2.246 Е, 2.248 Е, and 2.273 Е). The unit cell parameters of the complex are a = 9.494(1) Е, b = 10.479(1) Е, c = 12.474(2) Е, α = 84.55(1)°, β = 70.08(1)°, γ =
70.72(1)°, V = 1255.8(4) Е³, space group Z = 2; C₁₉H₁₀O₁₀Os₃; d_calc = 2.922 g/cm³, 3085 I_hkl > 2σ_I of 3611 collected reflections; R = 0.0252. The structure of Os₃(μ,η²-O=CC₆H₅)(η³-C₃H₅)(CO)₉ is molecular. The plane of the Os₃ triangle and the OsCOOs plane are connected according to the "butterfly" principle with an angle of 103.4° between them. The Os-Os distances in the cluster core vary from 2.836(1) Е to 2.844(1) Е; the Os-C_carb distances are 1.88(1)-1.97(1) Е; the distances to the atoms of the bridging ligands are Os-C 2.11(1), Os-O 2.14(1) Е; the O-C bridging bond is 1.24(1) Е. The conformations of the Os₃(μ,η²-O=CC₆H₅)(η³-C₃H₅)(CO)₉ triosmium cluster were studied theoretically. The potential curve of the internal rotation of the allyl ligand relative to the Os(1)-С(9) bond was determined. The rotation barrier of the allyl ligand in crystal relative to the Os(1)-С(9) bond is 8.38 kJ/mol, and the rotation of the ligand is not hindered. The effects of the intra- and intermolecular interactions on the conformation state of the cluster complex is considered.

An X-ray study of the crystals of bicyclic compounds containing fluorinated aromatic and nonfluorinated heteroaromatic rings, 5,6,7,8-tetrafluoroquinoline, 5,6,8-trifluoroquinoline, 5,7-difluoroquinoline, 5,7,8-trifluoro-2-phenylquinoline, and 5,7,8-trifluoro-6-trifluoromethylquinoline, was carried out. The basic supramolecular motifs and the underlying intermolecular interactions that control the lattice structure of these compounds were investigated. B3LYP DFT quantum-chemical calculations (6-311G(d,p) basis set) and the topological analysis of the electron density distribution in terms of Bader's QTAIM theory were performed for the compounds. It is shown that the intermolecular interactions in question, traditionally regarded as nonvalent interactions, are related, to a definite extent, to the formation of very weak covalent chemical bonds in the intermolecular space due to the overlap of the "tails" of the molecular wave functions.

Three modifier compounds that stabilize the phase state of ammonium nitrate over a wide range of temperatures, 1,3,5-trihydroxyisocyanuric acid dihydrate (1), 4-aminouracil (2), and 4-aminouracil monohydrate (3) were studied by X-ray diffraction. Strong donor-acceptor intermolecular interactions were found for structures 2 and 3. The electronic parameters of the molecules were calculated by quantum-chemical methods, and it was found that additional intermolecular interactions were possible.