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Journal of Structural Chemistry (v.43, #3)

Geometry of Transition Metal Complexes with Bipyridine in the Excited States by V. I. Baranovskii; O. O. Lyubimova; A. A. Makarov; O. V. Sizova (pp. 373-382).
A technique for estimating the changes in the geometrical structural parameters of complex compounds during charge-transfer electron excitations is proposed. The method combines the experimental Raman resonance data, the wave packet dynamics procedure, and quantum-chemical calculations of the geometry and vibrational spectra of relatively small fragments of the complex ion. The technique is used to determine the changes in the geometrical structure of 2, $$2'$$ -bipyridine during metal–ligand charge transfer excitations in Ru(II) complexes.

Calculation of 4-Center Coulomb Repulsion Matrix Elements in a Basis of Exponential Type Spherical AO Using 9-Dimensional Polyspherical Harmonics by B. K. Novosadov (pp. 383-389).
A method for calculating 4-center Coulomb repulsion integrals in a basis of exponential type AO with regular sectorial harmonics as angular terms is proposed. The initial integrals are represented as a partial differentiation operator with respect to the Cartesian coordinates of the centers of AO, acting on the scalar function which is a 4-center integral of s functions. Differentiation is performed by calculating the Fourier transform of this scalar function in 9-dimensional Euclidean space with the help of the sectorial harmonic argument summing theorem. Thus compact representation of quantum-chemical multicenter integrals is obtained in a basis of exponential type functions with arbitrary angular parts.

Calculation of 3-Center One-Electron Integrals $$leftlangle {AB|r_c^{ - 1} } ight angle $$ and Coulomb Repulsion Matrix Elements $$leftlangle {AB|CC'} ight angle $$ in an Exponential Type Spherical AO Basis by B. K. Novosadov (pp. 390-400).
A new method for calculating 3-center one-electron integrals and matrix elements of electron interaction of $$leftlangle {AB|CC'} ight angle $$ type in MO LCAO theory, where A, B, and C are the centers of exponential type AO including Slater and hydrogen-like basis functions, has been developed. Integrals of this type are reduced to double integrals over the square with edge 1. This provides the grounds for effective calculation of quantum-chemical 3-center integrals in a basis of exponential type spherical functions.

Structural Similarity and IR Spectrum Modeling Using the Spectrum–Fragment Composition Database by V. N. Piottukh-Peletskii; K. S. Chmutina; M. V. Korolevich; R. G. Zhbankov; B. G. Derendyaev (pp. 401-411).
It is shown on numerous examples that IR spectra of organic compounds may be modeled by using the spectra of the structural analogs selected from the database. This paper presents a technique for model construction and the results of modeling along with some examples of model and experimental spectra. The applicability of this approach to modern and traditional methods of spectral analysis is discussed.

Association of Diphenylguanidine and Quantum-Chemical Calculations of the Structure of Its Cyclic Dimers by S. F. Bureiko; A. Koll; M. Przeslawska (pp. 412-422).
The frequencies and intensities of the two tautomeric structures of the N, $$N'$$ -diphenylguanidine monomer and its hydrogen-bonded cyclic dimers were calculated for structure elucidation of the monomer and dimer forms of this compound and identification of the stretching vibration band νNH of this molecule in solution. Ab initio HF/3-21G and B3LYP/6-31G(d,p) calculations of DPG monomers and cyclic associates suggest that the asymmetric tautomer is dominant, proving that the dimer structures with two C=(Ph)N...H–NPh hydrogen bonds prevail in solution. An assignment of IR absorption frequencies of DPG in solution is suggested.

Role of Tin Difluoride and Gallium Trifluoride in Glass Formation in SnF2–GaF3–BaF2 by L. N. Ignatieva; E. A. Stremousova; E. V. Merkulov; A. Yu. Beloliptsev (pp. 423-428).
The structure of glasses in SnF2–GaF3 and SnF2–GaF3–BaF2 systems was investigated by IR spectroscopy. It is shown that the glass structure in systems of this type is formed by two glass-forming agents: gallium trifluoride and tin difluoride. The introduction of 5 mole % barium difluoride shifts the edge of the absorption band to the low-frequency region.

Internal Mobility, Phase Transitions, and Ionic Conductivity in Na(NH4)6Zr4F23 and Li(NH4)6Zr4F23 by V. Ya. Kavun; V. I. Sergienko; N. F. Uvarov; T. F. Antokhina (pp. 429-435).
The dynamics of fluoride and ammonium ions in Na(NH4)6Zr4F23 (I) and Li(NH4)6Zr4F23 (II) was studied by 1H and 19F NMR in the temperature range 170-440 K. Types of ionic motion were determined, and their activation energies were evaluated. In I, phase transitions were found in the temperature ranges 360-370 and 410-415 K. The experimental values of conductivity σ of Na(NH4)6Zr4F23 and Li(NH4)6Zr4F23 (σ ≈ 4 × 10-3 S/cm at T = 420 K) permit one to attribute these fluorides to the class of superionic conductors.

Crystal Structure and Dynamics of Water Molecules and Fluoride Ions in NaKSbF5·1.5H2O and NaRbSbF5·1.5H2O by A. V. Gerasimenko; V. Ya. Kavun; V. I. Sergienko; D. Yu. Popov; L. A. Zemnukhova; R. L. Davidovich (pp. 436-444).
The atomic structures of crystal hydrates were determined at 173 and 293 K for NaKSbF5·1.5H2O (I) and at 293 K for NaRbSbF5·1.5H2O (II). Crystals I and II are isostructural, space group $$P2_1 /{kern 1pt} m$$ . The dynamics of water molecules and complex ions was investigated by NMR in the range 170-440 K. The existence of a phase transition of order–disorder type in compounds I and II was established. A mechanism leading to the diffusion motion of fluoride ions in II is suggested, and dehydration of the compounds is considered.

State of Hydrogen in Cubic Zirconium Dihydride by R. N. Pletnev; A. Ya. Kupryazhkin; A. V. Dmitriev; E. V. Zabolotskaya (pp. 445-448).
PMR spectra have been recorded and the proton spin–lattice relaxation time has been measured for cubic hydride δ-ZrH2. It is found that above 290 K thermally activated diffusion of hydrogen takes place. In the region 230 K, a reversible phase transition takes place, which is due to a change in the state of hydrogen in the crystal lattice of zirconium dihydride. Possible mechanisms of this transition are discussed.

Application of Molecular Dynamic Simulation of Water Clusters with CO and CO2 Molecules to Binary Nucleation Problems by A. E. Galashev; V. N. Chukanov; G. I. Pozharskaya (pp. 449-457).
The thermodynamic properties of pure water clusters and aqueous aggregates with either CO or CO2 molecule were calculated by the molecular dynamics method. The resulting size dependence of the surface tension of the clusters was used to determine the size of the critical seeds. The rate of homogeneous and binary nucleation in atmospheric air was estimated. The role of polar and nonpolar impurity molecules at the initial stage of steam condensation is discussed.

Physicochemical Properties of Water Clusters in the Presence of HCl and HF Molecules. Molecular Dynamic Simulation by A. E. Galashev; G. I. Pozharskaya; V. N. Chukanov (pp. 458-466).
The molecular dynamic method is used to study the physicochemical properties of water clusters containing HCl and HF molecules. These impurity molecules have the ability to undergo hydration in water vapor. In clusters with the same number of water molecules, large dipole moments are induced for HCl, and smaller ones, for HF. The diffusion coefficient of the impurity in the clusters is slightly lower than the analogous characteristic for water molecules and exhibits nonmonotonous behavior with increasing size of the aggregate.

Relationship between the Structural State of Water and the Character of Ion Hydration in Concentrated 1:1 Aqueous Solutions of Electrolytes in Extreme Conditions by R. D. Oparin; M. V. Fedotova; V. N. Trostin (pp. 467-472).
It is suggested that the association parameter A be used as an indicator demonstrating the effect of extremal conditions on the structure of water in the series of solutions $$LiCl{kern 1pt} o {kern 1pt} NaCl{kern 1pt} o {kern 1pt} KCl$$ . Analysis of the diagrams “A parameter–external conditions” permitted us to establish that compression has a weak effect on association of water molecules in the systems, in which case the effect of the ion field on the mutual ordering of solvent molecules does not change. In conditions of strong compression in NaCl–H2O, positive hydration of Na+ changes to negative. On the contrary, at elevated temperatures, the probability of association of bulk water molecules increases and the effect of ions on the structure of the solvent decreases. Positive hydration of Li+ and negative hydration of K+ become less pronounced, and Na+ has no ordering effect on the structure of the solvent any longer.

Structural Properties of Concentrated Aqueous Solutions of Lithium Chloride Near the Critical Point of Water as Calculated by the Integral Equation Method by M. V. Fedotova; R. D. Oparin; V. N. Trostin (pp. 473-477).
The integral equation method was used to study structure formation in concentrated aqueous solutions of lithium chloride in the near-critical region (P = 20 MPa, T = 298-623 K). It is found that when the LiCl–H2O system passes from a concentrated state to a melt-like one ( $$LiCl{kern 1pt} :{kern 1pt} 8H_{2} O o {kern 1pt} LiCl{kern 1pt} :{kern 1pt} 6H_{2} O{kern 1pt} o {kern 1pt} LiCl{kern 1pt} :{kern 1pt} 4H_{2} O{kern 1pt} o {kern 1pt} LiCl{kern 1pt} :{kern 1pt} 3H_{2} O$$ ), some of its structural characteristics change oppositely depending on temperature, leading to anomalous structural properties of the most concentrated solution. Analyzing the temperature dependence of coordination numbers we established the temperature range and the steps of structural changes in the LiCl–H2O system.

Cucurbituryl Associates with Trigonal and Cubane Transition Metal Cluster Aqua Complexes by A. V. Virovets (pp. 478-487).
This paper discusses a new approach to crystallization of cluster aqua anions using an organic macrocyclic cavitand — cucurbituryl. Six water molecules coordinated to the cluster nucleus are geometrically complementary to the six oxygen atoms of the C=O groups of cucurbituryl, forming with them a stable system of hydrogen bonds. The resulting associates have low solubility and good crystallization properties. The crystal structures of 15 compounds of this type have been studied, and the main structural features have been revealed.

Syntheses of [Rh(NH3)5Cl][MCl6] (M = Re, Os, Ir) and Investigation of Their Thermolysis Products. Crystal Structure of [Rh(NH3)5Cl][OsCl6] by S. A. Gromilov; S. V. Korenev; I. A. Baidina; I. V. Korolkov; K. V. Yusenko (pp. 488-494).
Binary complex salts [Rh(NH3)5Cl][MCl6], where M = Re, Os, Ir, have been synthesized and characterized. X-ray diffraction analysis indicated that the salts are isostructural. According to X-ray phase analysis, the products of their thermolysis in hydrogen are monophase stoichiometric nonequilibrium solid solutions Rh0.5M0.5 (M = Re, Os, Ir). The molecular and crystal structures of [Rh(NH3)5Cl][OsCl6] were determined in an X-ray structural analysis.

Gossypol Clathrates. Structure of a Gossypol Complex with Isobutylacetate by S. A. Talipov; B. T. Ibragimov (pp. 495-500).
The natural compound gossypol forms stable clathrates with isobutylacetate. The clathrates were investigated by X-ray diffractometry. The crystallographic parameters of single crystals were determined and refined using 15 reflections on a Syntex P21 four-circle automatic diffractometer. The crystals are monoclinic, C30H30O8·0.5C6H12O2, a = 11.444(2), b = 30.724(5), c = 16.521(3) Å, γ = 88.17°, V = 5805.9(17) Å3, M = 1153.24, Z = 4, d calc = 1.32 g/cm3, space group $$P2_1 /n$$ , R = 0.047 for 4686 reflections. The clathrates are not isostructural to any of the previously prepared guest–host complexes, although there are many common features between the structure of the given solvate and the gossypol clathrate and the unbranched analog of isobutylacetate.

Crystal Structure of Diaqua(2.2.2-cryptand)strontium Bis(thiocyanate) by A. N. Chekhlov (pp. 501-506).
The crystal structure of the title compound, [Sr(C18H36N2O8)(H2O)2]2+·2SCN (I), was investigated by X-ray diffractometry: space group $$P2_1 /n$$ , a = 10.724(3), b = 15.512(3), c = 16.826(4) Å, β = 97.96(3)°, Z = 4. The structure was solved by direct methods. The full-matrix least-squares anisotropic refinement converged to R = 0.038 for all 3837 independent measured reflections (CAD-4 automatic diffractometer, $$lambda MoK_alpha $$ ). In the structure of I, the Sr2+ cation (c.n. 10) lies in the cavity of the cryptand ligand and is coordinated by all of its eight heteroatoms (6O+2N) and two O atoms of the two water molecules; its coordination polyhedron is a distorted two-base-centered bicapped trigonal prism. The cryptand ligand in I has an asymmetric conformation. The crystal structure of I has interionic hydrogen bonds (formed by the H atoms of the ligand water molecules) linking the complex cations and the SCN anions into complex infinite chains.

What Is the Structure of a Liquid? by G. A. Martynov (pp. 507-514).
Various methods of structure determination for liquids are considered. It is shown that the most fruitful technique is using the distribution functions. This is the only technique providing the calculation of the thermodynamic parameters of a liquid from the functions found in a numerical experiment.
Electronic Structure and Chemical Bonding in Wurtzite-Like Beryllium Monoxide by Yu. N. Makurin; A. A. Sofronov; V. S. Kijko; Yu. V. Emel'yanova; A. L. Ivanovskii (pp. 515-518).
IR Spectra of Ni(AA)2 and Ni(TFA)2 in Chloroform. Quantum-Chemical Simulation of Interaction between Ni(TFA)2 and CHCl3 by I. M. Oglezneva; É. S. Fomin; L. N. Mazalov; G. I. Zharkova (pp. 519-522).
Crystal Structure of the Tetragonal Form of LuBa2Cu3O6+x (x = 0) by N. V. Podberezskaya; L. P. Kozeeva; M. Yu. Kameneva; A. V. Virovets; G. V. Romanenko; D. Yu. Naumov; N. V. Pervukhina (pp. 523-526).
Synthesis and X-Ray Diffraction Study of [M(NH3)4][OsBr6] (M = Pd, Pt) by S. A. Gromilov; S. V. Korenev (pp. 527-529).
Crystal Structure of 5-Nitro-4-(2-nitrophenyl)-6-phenyl-3,4-dihydro-(1H)-pyrimidin-2-one by T. V. Rybalova; V. F. Sedova; Yu. V. Gatilov; O. P. Shkurko (pp. 539-543).
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