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Journal of Structural Chemistry

2008 year, number 4

1.
On the Mechanism of Mechanochemical dimerization of anthracene. quantum-chemical calculation of the electronic structure of anthracene and its dimer

V. M. Tapilin, N. N. Bulgakov, A. P. Chupakhin, . A. Politov
Keywords: anthracene, dimer, electronic structure, mechanochemistry
Pages: 609-615

Abstract >>
The electronic structure of anthracene, its dimer, and intermediate structures composed of two anthracene molecules were calculated in the density functional theory. The calculated potential barrier to anthracene dimerization is ~55 kcal/mol; the dissociation barrier is ~45 kcal/mol. The pressure required for the reaction to reach the transition state and acting on the anthracene crystal is ~60 kbar. Lower pressures, ~10 kbar, are required for molecules to approach each other to distances of ~3 Å, at which tunnel dimerization is possible for photoexcited molecules.
																								



2.
STRAINED BONDS IN [Re4Q4X12]4- CLUSTER COMPLEXES (Q = S, Se, Te; X = F, CN-) ACCORDING TO AIM AND ELF DATA

M. R. Ryzhikov, S. G. Kozlova, S. P. Gabuda
Keywords: AIM, ELF, cluster complexes, strained bonds
Pages: 616-622

Abstract >>
The electron density distribution in [Re4Q4X12]4- cubane-like clusters (Q = S, Se, Te; X = F, CN) was investigated by the AIM and ELF topological quantum-chemical methods. The Re-Re, Re-Q, and Re-X interatomic interactions are characterized by bcp type critical binding points and are strained.
																								



3.
AB INITIO QUANTUM-CHEMICAL STUDY OF THE MECHANISM OF METHOXIDE ION FORMATION IN /dmso/3 SYSTEMS ( = Li, Na, K)

E. Y. Larionova, N. M. Vitkovksaya, V. B. Kobychev, N. B. Caempf, B. A. Trofimov
Keywords: methoxide ion, vinylation, mechanism, quantum-chemical calculations
Pages: 623-627

Abstract >>
The profile of the reaction 3 + → 3 + 2 in the presence of an alkali (, = Li, Na, K) was investigated by the ab initio quantum-chemical method for the gas phase (with allowance for the solvent) within the continuum model. The proton transfer and the formation of the alkaline methoxide molecule in /DMSO/3 systems ( = Li, Na, K) in the alkali-methanol pre-reaction complexes can take place without their preliminary dissociation and are barrier-free reactions.
																								



4.
THEORETICAL STUDIES ON THE STRUCTURES, PROPERTIES, AND AROMATICITIES OF FLUORINATED ARSABENZENES

R. Ghiasi, M. Monajjemi, E.E. Mokarram, P. Makkipour
Keywords: arsabenzene, fluorinated aromatics, aromaticity, NICS, B3LYP, GIAO, CSGT
Pages: 628-632

Abstract >>
The electronic structures and properties of the fluorinated arsabenzenes series have been investigated using the basis set 6311+G(d,p) and hybrid density functional theory. Basic measures of aromatic character derived from molecular orbitals and magnetic criteria (anisotropic susceptibilities and nucleus-independent chemical shift) are considered. Energetic criteria suggest that F3, F36, H36 and H3 isomers are the most stable isomers in the mono, di, tri and tetrafluorinated species, respectively. Analysis of χaniso and the HOMOLUMO gaps are not compatible with the NICS results. The NICS values show that aromaticity is greater in the fluorinated derivatives.
																								



5.
MOLECULAR STRUCTURE OF OCTACHLOROTRISILANE Si3Cl8

Y. S. Ezhov, S. A. Komarov, E. P. Simonenko, V. G. Sevast'yanov
Keywords: gas-phase electron diffraction, quantum chemistry, octachlorotrisilane, molecular structure, internal rotation
Pages: 633-639

Abstract >>
The parameters of the geometrical configuration of octachlorotrisilane Si3Cl8 were determined by quantum-chemical and gas-phase electron diffraction methods at 3032 K. The calculated barrier to the internal rotation of SiCl3 groups relative to the Si-Si bond was calculated.
																								



6.
STRUCTURE, FORCE FIELDS, AND VIBRATIONAL SPECTRA OF CERIUM TETRAHALIDES

V. G. Solomonik, A. Y. Yachmenev, A. N. Smirnov
Keywords: cerium tetrahalides, molecular structure, force constants, vibration frequencies, quantum-chemical calculations
Pages: 640-648

Abstract >>
The geometrical structure, force fields, and vibrational spectra of CeX4 (X = F, Cl, Br, I) were investigated by second, third, and fourth order Möller-Plesset perturbation theory, CISD+Q configuration interaction method, and the CCSD(T) coupled cluster method. Calculations on CeF4 were also performed by multiconfiguration second order perturbation theory MCQDPT2/CASSCF. The wave function of the ground state of CeX4 molecules was found to be appreciably non-one-configurational; this property increases from cerium fluorides to iodides and leads to the divergence of the series of Möller-Plesset perturbation theory. The calculated data point to a tetrahedral equilibrium nuclear configuration in CeX4 molecules. The energy barriers to the inversion of the tetrahedral CeX4 molecules via the square configurations are high enough, 74-89 kJ/mol. The calculated vibration frequencies, effective internuclear distances, and mean amplitudes of nuclear vibrations in CeF4 agree with IR and Raman spectroscopic and high-temperature gas-phase electron diffraction data.
																								



7.
THEORETICAL STUDY OF STRUCTURE, STABILITY AND INFRARED SPECTRA OF HYDROGEN BONDING COMPLEXES PAIRING N-NITROSODIETHANOLAMINE (NDELA) AND ONE TO FIVE WATER MOLECULES

R. Alizadeh, N.M. Najafi
Keywords: hydrogen bond, clusters, nitrosamine, computations, B3LYP
Pages: 649-654

Abstract >>
A theoretical study of the interaction between N–nitrosodiethanolamine (NDELA) molecule and one to five molecules of water has been performed at the B3LYP level using a large polarized basis set. The calculated complexation energies (corrected for BSSE and ZPVE)
of NDELA with one, two, three, four and five molecules of water are –4.62, –9.83, –15.29, –21.60, and –25.10 kcal/mol respectively at the B3LYP/6–311++G** level. In all complexes studied there are red shifts in the vibrational frequencies of the O–Hs of NDELA and water molecules along with increases in the corresponding IR intensities.
																								



8.
TEMPERATURE EFFECTS ON THE IR SPECTRA OF CRYSTALLINE AMINO ACIDS, DIPEPTIDES, AND POLYAMINO ACIDS. II. L− and DL−SERINES

Y. A. Chesalov, G. B. Chernobay, E. V. Boldyreva
Keywords: serine, optical isomers, IR spectroscopy, hydrogen bonds
Pages: 655-666

Abstract >>
The IR spectra of L- and DL-serines HN-CH(CH2OH)-COO- (without diluents) were investigated in the temperature range 93-413 K; the changes in the IR spectra due to temperature variations were correlated with previously obtained diffraction data on anisotropic compression of structure and changes in the geometrical parameters of the hydrogen bonds.
																								



9.
MICROWAVE SPECTRUM, CENTRIFUGAL PERTURBATION, DIPOLE MOMENT, AND CONFORMATION OF 5−METHYL−1,3−DIOXANE

A. K. Mamleev, R. V. Galeev, L. N. Gunderova, M. G. Faizullin, A. A. Shapkinu
Keywords: 5-methyl-1, 3-dioxane, microwave spectrum, conformation, dipole moment
Pages: 667-671

Abstract >>
The microwave spectrum of 5-methyl-1,3-dioxane was studied in the frequency range 12-35 GHz. The and type rotation transitions with J ≤ 30 were identified. The rotational constants =
4658.5244(33) MHz, = 2383.3930(12) MHz, and = 1724.28907(88) MHz and the quartic constants of the centrifugal distortion of the molecule in the ground vibrational state were determined. The components of the dipole moment were found, μ = 1.76 0.01 D and μ = 1.10 0.01 D; the net dipole moment of the molecule is μ = 2.08 0.01 D. 5-Methyl-1,3-dioxane was calculated by the B3PW91/aug-cc-pVDZ density functional theory method. The calculated data are compared with the experimental data. The most stable conformation is the chair conformation with an equatorial orientation of the methyl group.
																								



10.
NMR STUDY OF THE SPATIAL STRUCTURE OF SYNTHETIC PYRETHROIDS

N. S. Mirzabekova, N. E. Kuzmina, E. S. Osipova, O. I. Lukashov
Keywords: pyrethroids, spatial isomers, ROESY
Pages: 672-677

Abstract >>
The spatial isomers of the new synthetic analogs of ethyl permithrinic ether and permethrin were investigated by NMR (1, 13, DEPT (distortionless enhancement by polarization transfer), COSY (correlation spectroscopy), CHCORR (heteronuclear (C, H) shift correlation spectroscopy), ROESY (rotating-frame Overhauser effect spectroscopy)). Several tendencies were revealed in the 1 and 13 chemical shifts of the α atoms of the substituents in the 2nd and 3rd positions of the cyclopropane ring. For substituents cis-orientated relative to the ester group, the spectra show a paramagnetic shift of the 1 signals and the diamagnetic shift of the 13 signals relative to the trans-orientated substituents. The 1 and 13 chemical shifts of the α atoms of the substituents in the 2nd and 3rd positions of the cyclopropane ring permit an unambiguous determination of the stereochemistry of ethyl permethrinic ether and permethrin analogs.
																								



11.
ANTISYMMETRY AND STABILITY OF AQUEOUS SYSTEMS. III. CONFORMATIONS OF THE HEXAGONAL RINGS

M. V. Kirov
Keywords: water, antisymmetry, asymmetry, hydrogen bonds, conformation, isomorphism
Pages: 678-683

Abstract >>
The antisymmetry of proton configurations was studied for the hexagonal water rings with different conformations. The change in the direction of all hydrogen bonds was used as an additional symmetry operation. The ring configuration energies were calculated using the intermolecular interaction potentials. For different ring conformations, the relationships between antisymmetry and energy were analyzed and compared.
																								



12.
ANTYSYMMETRY AND STABILITY OF AQUEOUS SYSTEMS. IV. SMALL CLUSTERS OF ARBITRARY FORM

M. V. Kirov
Keywords: water, cluster, antisymmetry, supramolecular asymmetry, ab initio calculations
Pages: 684-687

Abstract >>
The antisymmetry of small water clusters of various configurations with three to five molecules, which are stable according to the ab initio calculated data, was analyzed. The antisymmetry operation was alteration of the direction of all hydrogen bonds including the direction of the external unrealized -bonds. It was found that most configurations of small clusters were antisymmetric. Other configurations form pairs of antipode configurations with very close energies.
																								



13.
VOLUME PROPERTIES AND STRUCTURE OF AQUEOUS SOLUTIONS OF UREA AT 263-348 K

V. P. Korolev
Keywords: urea, aqueous solutions, volume properties, structure
Pages: 688-695

Abstract >>
The apparent molar volume of urea φ in aqueous solution in the range = 273-323 K and m = 1-10 (molality) depends linearly on m1/2. An equation for φ(m, T) was derived. The partial molar characteristics of urea and water (volume, dilatability, and temperature coefficients of volumes) were calculated. The dependences have characteristic points (extrema, inflection points), shifted to the region of lower temperatures for dilute solutions. The dependences for 2m and 4m of the urea solution retain the characteristics of the Y1(T) of pure water. In these solutions, the proper structure of water is preserved.
																								



14.
PROPERTIES AND STRUCTURE OF AQUEOUS UREA UP TO THE SINGULAR TEMPERATURE OF OVERCOOLED WATER: ISOTOPY EFFECTS

V. P. Korolev
Keywords: urea, aqueous solutions, properties, structure, isotopy
Pages: 696-706

Abstract >>
In equations for the partial volume, dilatability, heat capacity, and adiabatic compressibility of aqueous urea, the properties are "fitted" to the singular temperature Ts of overcooled water Ts = 227.15 K
(R. J. Speedy, J. Phys. Chem., 91, 3354 (1987)). The equations for the characteristics of D2O-(ND2)2CO and 2O-(N2)2CO systems were obtained by scaling the temperature to 6 and 9.4 K, respectively. The properties of infinitely dilute solutions did not reveal the sign reversal of the isotope effect. The isoconcentrates of the partial volumes and dilatability form wagging lines in the region of low temperatures. The temperature dependences of the properties have extrema and inflection points, while the isotope effects in solutions of finite concentrations experience sign reversal. The maximum density temperature (MDT) of the solution decreases as the urea concentration increases, and also on passing from D2O-(ND2)2CO to H2O-(NH2)2CO. Thus, for the 8m solution, the MDT is 259.6 K (protium system) and 266.7 K (deuterium system). The difference is almost equal to the shift of the MDT after the H2O → D2O transition (7.2 K).
																								



15.
COMPOSITION AND STRUCTURE OF HETEROASSOCIATES FORMED IN a BINARY LIQUID SYSTEM HF-CH3CN

E. G. Tarakanova, G. V. Yukhnevich
Keywords: binary liquid system, IR spectrum, quantum chemical calculation, hydrogen bond, heteroassociates, fluoric hydrogen, acetonitrile
Pages: 707-716

Abstract >>
The concentration dependence of normalized absorbance (to the total number of moles of components in one liter) of HF solutions in acetonitrile (1:12-10:1) is analyzed. It is found that in the binary liquid system (BLS) under study molecular complexes with stoichiometric 1:1 and ~10:1 ratios of molecules occur along with the heteroassociates (HAs) found previously with the ratio HF:CH3CN of 4:1. For each of the HAs the concentration range at which it is formed in BLS is evaluated, and the positions of HF stretching vibrational bands are found. Optimum configurations and vibrational frequencies of molecular complexes (HF)m⋅(CH3CN)n (m = 1-6, n = 1-2) of various topology are calculated using the density functional method (B3LYP/6-31 ++ G (d, p)). Their relative stability and the structure peculiarities are studied; complexation tendencies in the HF-CH3CN system are revealed. The structure of HAs with 1:1 and 4:1 stoichiometric ratios of molecules is determined by comparing the results of calculations and experiment.
																								



16.
THERMODYNAMIC PARAMETERS OF SOLVATION OF NONELECTROLYTES IN AQUEOUS SOLUTIONS OF AMIDES OF CARBOXYLIC ACIDS

A. M. Zaichikov, M. A. Krest'yaninov
Keywords: solvation of nonelectrolytes, aqueous solutions of amides, interaction and reorganization contributions, structure of solutions, intermolecular interactions
Pages: 717-724

Abstract >>
Interaction and reorganization contributions to solvation enthalpies of nonelectrolytes in aqueous solutions of amides of carboxylic acids with different degree of N-substitution and N-methylpyrrolidone are calculated. The data are discussed using structurally thermodynamic characteristics of water-amide systems obtained by us previously. It is found that the type of concentration dependence of the solvation enthalpy of nonelectrolytes in all solutions investigated is determined by the type of reorganization component. It is shown that the highest solvation exothermicity of nonelectrolytes in water is due to the lowest value of the reorganization contribution in spite of that nonelectrolytes interact weaker with water than with non aqueous components.
																								



17.
CRYSTAL STRUCTURES OF CESIUM AND RUBIDIUM CHLORITES

A. I. Smolentsev, D. Y. Naumov
Keywords: crystal structure, chlorites, rubidium, cesium
Pages: 725-728

Abstract >>
Rubidium and cesium chlorites are prepared and studied by single crystal and powder X-ray diffraction. The compounds are isostructural; crystallize in the orthorhombic system; space group Cmcm, Z = 4. Unit cell parameters: a = 6.3464(8) Å, b = 6.4223(8) Å, c = 7.7493(9) Å for RbClO2 and a = 6.5998(9) Å, b = 6.6116(9) Å, c = 8.3161(11) Å for CsClO2. The structures can be represented as 3D frameworks formed by metal cations and chlorite anions acting as tetradentate bridging and bidentate chelating oxygen ligands.
																								



18.
REFINEMENT OF THE CATION DISTRIBUTION IN Nb-Mo DOUBLE OXIDE

T. Y. Kardash, L. M. Plyasova, V. M. Bondareva, A. N. Shmakov
Keywords: powder X-ray diffraction, Rietveld refinement, X-ray anomalous scattering, Nb2Mo3O14 structure
Pages: 729-735

Abstract >>
The structure of Nb2Mo3O14 double oxide is refined from powder data using synchrotron radiation and the anomalous scattering effect; space group P21m is found for the material. It is demonstrated that in the tetragonal unit cell with parameters = 23.173 Å, = 4.0027 Å Nb5+ and 6+ ions are stochastically distributed in 6 octahedra and 7 pentagonal bipyramids of the polygonal network structure of the 514 type.
																								



19.
BALANCE, UNIFORMITY, AND ASYMMETRY OF THE STRUCTURE OF VOLBORTHITE Cu3(OH)2(V2O7)⋅2H2O

A. A. Kashaev, I. V. Rozhdestvenskaya, I. I. Bannova, A. N. Sapozhnikov, O. D. Glebova
Keywords: volborthite structure, Cu-octahedra, V-tetrahedra, structure balance, structural homogeneity, hydrogen bond
Pages: 736-740

Abstract >>
Four structural models of volborthite Cu3(OH)2(V2O7)⋅2H2O (a = 10.646(2) Å, b = 5.867(1) Å, c =
14.432(2) Å, β = 95.19(1), V = 897.7(5) Å3, Z = 4, R/Rw = 0.038/0.046) calculated in the space groups determined from the systematic absences are compared. Based on the structure balance and the similarity of constituting polyhedra, values of the R factor, and isotropic thermal parameters, the space group Ia is found to be preferable, which is the only possible asymmetric and uniform variant. Hydrogen atoms of -groups, oxygen atoms and, partially, hydrogen atoms of water are localized.
																								



20.
STRUCTURAL INVESTIGATION OF HYDRATE COMPOUNDS OF THE TETRAISOAMYLAMMONIUM FORM OF POLYACRYLATE ION EXCHANGE RESINS. CRYSTAL STRUCTURE OF A CLATHRATE HYDRATE OF LINEAR TETRAISOAMYLAMMONIUM POLYACRYLATE

D. V. Soldatov, K. Suwinska, I. S. Terekhova, A. Y. Manakov
Keywords: polymer hydration, two-component system, inclusion compounds, polymeric guest, crystal structure
Pages: 741-747

Abstract >>
A polyhydrate of the tetraisoamylammonium salt of linear (uncrosslinked) polyacrylate (~25 monomeric units in the polyacrylate chain) is described and compared to polyhydrates of cross-linked tetraisoamylammonium polyacrylates (0.5-3% of cross-linking with divinylbenzene or divinylsulfide). Powder X-ray diffraction reveals that the polyhydrate containing a linear polyacrylate molecule has the same structure (hexagonal, a = 12.26 Å, c = 12.71 Å at 3C) as polyhydrates of the cross-linked polyacrylate molecules. A single crystal of the polyhydrate obtained from an aqueous solution of linear tetraisoamylammonium polyacrylate is studied by X-ray diffraction at -173C. The structure is hexagonal; space group P-6m2; the polyhydrate framework is a slightly distorted variant of the hexagonal structure-I of clathrate hydrates.
																								



21.
SOFT ACTIVATION OF THE CS BOND: X-RAY DIFFRACTION AND SPECTROSCOPIC STUDY OF THE CLUSTER Ru44-S)(μ,η3-C3H5)2(CO)12

I. Y. Prikhod'ko, V. P. Kirin, V. A. Maksakov, A. V. Virovets, A. V. Golovin
Keywords: crystal structure, ruthenium carbonyl clusters, allyl, activation of C-S bonds
Pages: 748-752

Abstract >>
The complex Ru44-S)(μ,η3-C3H5)2(CO)12 is prepared and examined by IR and NMR spectroscopy; its crystal structure is determined (an automatic Bruker-Nonius X8 Apex four-circle diffractometer equipped with a 2-D CCD-detector, 100 K, graphite-monochromated molybdenum source, λ = 0.71073 Å). The crystal belongs to the orthorhombic crystal system with unit cell parameters a = 19.3781(9) Å, b = 12.2898(7) Å, c = 10.1726(4) Å, V = 2422.6(2) Å3, space group Pnma, Z = 4, composition C18H10O12Ru4S, dx = 2.343 g/cm3. The molecule of point symmetry C1 is situated on the mirror plane of the space group Pnma, two carbonyl groups at Ru2 and Ru3 atoms overlapping with the allylic ligand with a weight of 50% so that carbon atoms coincide. Thus, we have a racemic structure with two overlapping enantiomers of the molecule of Ru44-S)(μ,η3-C3H5)2(CO)12.
																								



22.
CRYSTAL STRUCTURES OF SEVEN-COORDINATE (NH4)2[MnII(edta)(H2O)]⋅3H2O, (NH4)2[MnII(cydta)(H2O)]⋅4H2O and K2[MnII(Hdtpa)]⋅3.5H2O COMPLEXES

X.F. Wang, J. Gao, J. Wang, ZH.H. Zhang, Y.F. Wang, L.J. Chen, W. Sun, X.D. Zhang
Keywords: manganese(II) chelate, ethylenediamine-N, N, N?, N?-tetraacetic acid (H4edta), trans-1, 2-cyclohexanediamine-N, N, N?, N?-tetraacetic acid (H4cydta), diethylenetriamine-N, N, N?, N?, N?-pentaacetic acid (H5dtpa)
Pages: 753-759

Abstract >>
The title compounds, (NH4)2[MnII(edta)(H2O)]⋅3H2O (H4edta = ethylenediamine-N,N,N′,N′-tetraacetic acid), (NH4)2[MnII(cydta)(H2O)]⋅4H2O (H4cydta = trans-1,2-cyclohexanediamine-N,N,N′,N′-tetraacetic acid) and K2[MnII(Hdtpa)]⋅3.5H2O (H5dtpa = diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid), were prepared; their compositions and structures were determined by elemental analysis and single-crystal X-ray diffraction technique. In these three complexes, the Mn2+ ions are all seven-coordinated and have a pseudo-monocapped trigonal prismatic configuration. All the three complexes crystallize in triclinic system in P-1 space group. Crystal data: (NH4)2[MnII(edta)(H2O)]⋅3H2O complex, a = 8.774(3) Å, b = 9.007(3) Å, c = 13.483(4) Å, α = 80.095(4), β = 80.708(4), γ = 68.770(4), V = 972.6(5) Å3, Z = 2, Dc
= 1.541 g/cm3, μ = 0.745 mm-1, R = 0.033 and wR = 0.099 for 3406 observed reflections with I ≥ 2σ(I); (NH4)2[MnII(cydta)(H2O)]⋅4H2O complex, a = 8.9720(18) Å, b = 9.4380(19) Å, c = 14.931(3) Å, α = 76.99(3), β = 83.27(3), γ = 75.62(3), V = 1190.8(4) Å3, Z = 2, Dc = 1.426 g/cm3, μ = 0.625 mm-1, R = 0.061 and wR = 0.197 for 3240 observed reflections with I ≥ 2σ(I); K2[MnII(Hdtpa)]⋅3.5H2O complex, a = 8.672(3) Å, b = 9.059(3) Å, c = 15.074(6) Å, α = 95.813(6), β = 96.665(6), γ = 99.212(6), V = 1152.4(7) Å3, Z = 2, Dc = 1.687 g/cm3, μ = 1.006 mm-1, R = 0.037 and wR = 0.090 for 4654 observed reflections with I ≥ 2σ(I).
																								



23.
MOLECULAR STRUCTURE OF 1-METHYL-1- FLUOROQUASISILATRANE (2-METHYL-2-FLUORO-1,3-DIOXA-6-AZA-2-SILACYCLOOCTANE)

A. A. Korlyukov, M. G. Voronkov, É. A. Zelbst, E. A. Grebneva, O. M. Trofimova, M. Y. Antipin
Keywords: 1-methyl-1-fluoroquasisilatrane, 2-methyl-2-fluoro-1, 3-dioxa-6-aza-2-silacyclooctane, molecular structure, X-ray diffraction
Pages: 760-763

Abstract >>
The molecular structure of 1-methyl-1-fluoroquasisilatrane (2-methyl-2-fluoro-1,3-dioxa-6-aza-2-silacyclooctane) MeFSi(OCH2CH2)2NH (I) is determined by single crystal X-ray diffraction at 100 K. The coordination polyhedron of the silicon atom in this molecule is a slightly distorted trigonal bipyramid with an NH group and a strongly electron-withdrawing fluorine atom in the axial positions, and two endocyclic oxygen atoms and a 3 group in three vertices of the equatorial plane. The axial angle N→SiF is 171. The length of the transannular donor-acceptor bond N→Si (2.058 Å) is as small as in 1-fluorosilatrane. The axial bond F-Si (1.660 Å) is longer than that in 1-fluorosilatrane and tetrahedral silicon compounds.
																								



24.
ATOMIC WAVE MOtion IN MOLECULAR NANOSTRUCTURES

L. A. Gribov, N. I. Prokof'eva
Keywords: molecular vibrations, non-stationary processes
Pages: 764-768

Abstract >>
In large-scale molecular objects (nanostructures) such as dendromers, supramolecules, polymers, nanotubes, etc. external perturbations may have local character. When the perturbation is removed, atomic wave motions of a rather complex type may arise in the nanostructure. They can not only transfer signals inside the nanoobject, but also generate standing waves and antinodes and accumulate energy in other domains of the nanostructure, i.e., give rise to energy traps. These problems have not been addressed before. In this paper we propose a method to calculate the time-dependent evolution of these phenomena for large-scale molecular structures of arbitrary structure and size.
																								



25.
SUPRAMOLECULAR ARCHITECTURE IN THE CRYSTALS OF POLYFLUORINATED HOMOPHTHALIC ACIDS

. V. Rybalova, Y. V. Gatilov, Y. V. Zonov, V. ??. Karpov
Keywords: polyfluorinated 2-(carboxymethyl)benzoic (homophthalic acids), crystal structure, hydrogen bonding, C-Fπ and -Oπ interactions, supramolecular synthon
Pages: 769-774

Abstract >>
X-ray diffraction analysis of four perfluorinated homophthalic (2-carboxymethylbenzoic) acids is carried out. In the crystals of 2-carboxymethyl-3,4,5,6-tetrafluorobenzoic acid (1) the chains (1D architecture) form with the usual dimeric carboxylic C(O)OH:::O(HO)C synthon. The aromatic carboxylic group is disordered in the ratio 0.58:0.42 over two positions. In the crystals of 2-(carboxydifluoromethyl)-3,4,5,6-tetrafluorobenzoic (2) and 2-(1-carboxy-2,2,2-trifluoroethyl)-3,4,5,6-tetrafluorobenzoic acids (3) the layers (2D architecture) with dimeric and chain-like synthons C(O)OHO(HO)C are found. In the crystals of 2-[methoxycarbonyl(difluoromethyl)]-3,4,5,6-tetrafluorobenzoic acid (4) only dimers (0D architecture) form with the chain synthon that incorporates both an ester and a carboxylic group. In the crystals of 1 and 2 intermolecular -Oπ interactions, in the crystals of 4 C-Fπ interactions, and in 3 both types of interactions are observed.
																								



26.
CRYSTAL STRUCTURE OF K2[Mo3(PdPPh3)S4(C2O4)3(H2O)3]⋅0.5H2O

A. L. Gushchin, M. N. Sokolov, D. Y. Naumov, V. P. Fedin
Keywords: molybdenum, palladium, chalcogenide clusters, cuboidal clusters, X-ray analysis
Pages: 775-778

Abstract >>
By the reaction of [Mo3S4(C2O4)3(H2O)3]2- with PdCl2 and NH4H2PO2 as a reducing agent, followed by the addition of PPh3, a new oxalate cuboidal cluster complex [Mo3(PdPPh3)S4(C2O4)3(H2O)3]2- is obtained. It was isolated and structurally characterized as K2[Mo3(PdPPh3)S4(C2O4)3(H2O)3]⋅0.5H2O.
																								



27.
CRYSTAL STRUCTURE OF Tl5{[Nb2S4Br8]Br}

A. L. Gushchin, M. N. Sokolov, E. V. Peresypkina, V. P. Fedin
Keywords: cluster, thallium, niobium, crystal structure
Pages: 779-782

Abstract >>
By the high-temperature reaction of Nb2S4Br4 and TlBr a thallium salt of the anionic cluster complex [Nb2S4Br8]4- is obtained. Its crystal structure is determined by X-ray structural analysis. The complex is also characterized by Raman spectroscopy and electrospray-mass-spectrometry.
																								



28.
CRYSTAL STRUCTURE OF BIS(l-ARGININE)COPPER(II) HEXACHLORODIMERCURATE, [Cu(l-Arg)2]Hg2Cl6

M. Zabel, V. I. Pavlovskii, A. L. Poznyak
Keywords: crystal structure, complexes of Cu(II) with arginine, chloromercurate(II)-ions
Pages: 783-786

Abstract >>
By means of X-ray diffraction the chain structure of [Cu(l-Arg)2]Hg2Cl6 (monoclinic, a = 10.2348(9) Å, b = 9.1386(7) Å, c = 14.8521(14) Å, β = 97.455(11), space group P21) is established. The chains are formed by square-planar [Cu(l-Arg)2]2+ cations of the type trans-[Cu(N)2()2] (l-rg is the zwitter-ion of arginine; Cu-N 1.992 Å and 1.938(6) Å, Cu-O 1.953 Å and 1.967(4) Å) that are bonded to two adjacent binuclear [Cl2Hg(μ-Cl)2HgCl2]2- ions through its clorine atoms Cl (Hg-Cl bonds are within 2.34-2.78 Å). With these two additional CuCl contacts Cu adopts the geometry of an elongated octahedron with two apical Cl (Cu-Cl 2.961 Å and 3.064(3) Å).
																								



29.
STRUCTURE OF HEXAAQUAMAGNESIUM (II) BIS(4-p-AMINOBENZENESULFAMIDO-2,6- DIMETHOXYPYRIMIDINATE) PENTAHYDRATE

É. B. Miminoshvili, K. ??. Miminoshvili, L. ??. Beridze
Keywords: complexes, structural analysis, sulfadimethoxine, sulfanilamides
Pages: 787-790

Abstract >>
The X-ray analysis of a single crystal of Mg(C12H13N4O4S)2⋅11H2O, where (C12H13N4O4S)- is the anion of 4-p-aminobenzenesulfamido-2,6-dimethoxypyrimidine (sulfadimethoxine) is carried out. Unit cell parameters are: = 19.753(4) Å, b = 34.031(7) Å, c = 13.859(3) Å; β = 125.37(3), C2/c, Z = 8, R(F) = 0.042. The structure is built of [Mg(OH2)6]2+, (C12H13N4O4S)-, and water molecules and corresponds to the formula [Mg(OH2)6](C12H13N4O4S)2⋅5H2O. The IR bands of νasymSO2 and νsymSO2 are bathochromically shifted as a result of their participation in hydrogen bonding, and not because of any direct coordination of sulfadimethoxinate anion to the complexing atom through oxygen.
																								



30.
STRUCTURE OF the SYN-OXIMe of 2-N,N′-DIMETHYL-AMINO-5-METHYLBENZOPHENONE 16H18N2O

. V. Kulikov, L. K. Minacheva, . V. Mazepa
Keywords: syn-oxime, crystal structure, X-ray analysis, hydrogen bonds, mass-spectrometry fragmentation pattern
Pages: 791-794

Abstract >>
The structure of the syn-isomer of 2-N,N′-dimethylamino-5-methylbenzophenone oxime is studied by X-ray diffraction and mass-spectrometry. This molecular compound crystallizes in the triclinic system. Unit cell parameters are: a = 19.5318(10) Å, = 19.5439(17) Å, V = 6456.9(7) Å3, Z = 18, space group The molecules are linked into centrosymmetric pseudo dimers by hydrogen bonds -HN formed by the oxime groups. The pathway of the electron-impact induced decomposition of the compound is discussed.
																								



31.
MOLECULAR AND CRYSTAL STRUCTURE OF 4,4,4-TRIFLUORO-3,3-DIHYDROXY-1-THIOPHENE-2-YL-BUTANE-1-ONE

S. V. Shishkina, Y. V. Tishchenko, N. L. Karavaeva, N. V. Pogorelova, O. V. Shishkin
Keywords: 4, 4, 4-trifluoro-3, 3-dihydroxy-1-thiophene-2-yl-butane-1-one, 2-thenoyltrifluoroacetone, conformation, X-ray diffraction analysis, quantum chemical calculations
Pages: 795-797

Abstract >>
An X-ray diffraction analysis and quantum chemical calculations of hydrated 2-thenoyltrifluoroacetone show that the planar diketone, form of found in its metal complexes, does not occur in the free ligand. Hydrated with two geminal hydroxo groups has a non-planar structure stabilized by an intramolecular hydrogen bond.
																								



32.
CRYSTAL STRUCTURE OF 6,11-DIHYDRO-6,11-METHANO-5H-BENZO[5,6]CYCLOHEPTA[1,2-b]PYRIDINOL-11

. . Shusharina, K. Y. Koltunov, S. ??. Gromilov, . I. Smolentsev
Keywords: 6, 11-dihydro-6, 11-methano-5H-benzo[5, 6]cyclohepta[1, 2-b]pyridinol-11, X-ray analysis
Pages: 798-799

Abstract >>
X-ray structure of 6,11-dihydro-6,11-methano-5H-benzo[5,6]cyclohepta[1,2-b]pyridinol-11 is determined.
																								



33.
SYNTHESIS AND CRYSTAL STRUCTURE OF TWO DERIVATIVES OF BENZODIAZEPINES

G.Y.S.K. Swamy1, B. Sridhar2, K. Ravikumar3, K.S. Reddy4, V.V.N. Reddy5
1 Laboratory of X-ray Crystallography, Indian Institute of Chemical Technology, Hyderabad 500 007, India, swamygundimella@yahoo.com
2 Laboratory of X-ray Crystallography, Indian Institute of Chemical Technology, Hyderabad 500 007, India
3 Laboratory of X-ray Crystallography, Indian Institute of Chemical Technology, Hyderabad 500 007, India
4 Laboratory of X-ray Crystallography, Indian Institute of Chemical Technology, Hyderabad 500 007, India
5 Laboratory of X-ray Crystallography, Indian Institute of Chemical Technology, Hyderabad 500 007, India
Keywords: Crystal structure, X-ray diffraction, benzodiazepines, hydrogen bonding
Pages: 800-804

Abstract >>
Two benzodiazepine derivatives, C23H22N2O (I), 2-methyl-8-methoxy-2,4-diphenyl-2,3-dihydro-1H-1,5-benzodiazepine, and C22H17N3O2Br2 (II), 2-methyl-7-nitro-2,4-bis(4′-bromophenyl)-2,3-dihydro-1H-1,5-benzodiazepine, were studied by single crystal X-ray diffraction method. Compound (I) crystallizes in the monoclinic system, space group P21/c, a = 13.1703(17), b = 11.1990(14), c = 12.9093(16) Å, β = 107.831(2), V = 1812.6(3) Å3, Z = 4. Compound (II) crystallizes in the monoclinic system, space group P21/n, a = 11.7345(12), b = 12.7477(13), c = 13.5965(14) Å, β = 95.221(2), V = 2025.4(4) Å3, Z = 4. The molecules of (I) and (II) have T-shape form with the diazepine ring at the junction point. The seven membered central benzodiazepine ring in both structures adopt a twist-boat conformation. The crystal packing is stabilized by C-Hπ (in I) and C-HO (in II) interactions.