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Journal of Structural Chemistry

2010 year, number 3

1.
AB INITIO CALCULATIONS OF STRUCTURAL, ELASTIC, AND ELECTRONIC PROPERTIES OF SILVER NITRIDES

A. B. Gordienko, Y. N. Zhuravlev
Keywords: silver nitrides, crystal structure, elastic constants, polycrystals, elasticity moduli, band structure, density of states, Mulliken population, chemical bonding
Pages: 425-432

Abstract >>
The all-electron approach implemented in the CRYSTAL06 program is used along with a pseudopotential method in the pseudo-atomic orbital basis set to study the crystal structure, elastic constants and bulk moduli, the band structure and density of states for the family of silver nitrides. Calculations are performed within density functional theory with the use of local and gradient functionals to describe exchange and correlation. For the general type of the cubic lattice, all considered compounds can be put in the following order of their relative stability: AgN (rock salt structure), AgN2 (fluorite structure), Ag2N (cuprite structure), and Ag3N (anti-ReO2). It is shown that AgN, AgN2, and Ag2N are metals, whereas Ag3N is a semiconductor with a band gap of 0.25 eV. Chemical bonding in these compounds has ionic and covalent components, apart from the metal one.
																								



2.
A QUANTUM CHEMICAL STUDY OF THE STRUCTURE OF fluorinated silver acetate(i) monomers and dimers

Z. G. Bazhanova, Y. I. Tarasov, D. M. Kovtun, A. I. Boltalin, B. K. Novosadov, I. V. Kochikov
Keywords: silver acetates, quantum chemical calculations, potential energy surface scanning
Pages: 433-441

Abstract >>
Quantum chemical calculations of the equilibrium structure, potential energy surface cross-sections along the nonrigid degrees of freedom of (CF3COOAg)2, (CHF2COOAg)2, (CH2FCOOAg)2, and (CH3COOAg)2 dimers and the corresponding monomers are presented. The B3LYP method with the augmented cc-pVTZ basis set for C, O, F atoms and the Stuttgart 1997 RSC basis set together with the relativistic effective potential for Ag atoms is used. It is shown that in all dimers the eight-membered ring is a rather rigid planar fragment, and the Ag atoms can be bonded with the bond order of 0.2 in dimers. Almost free rotation of acyclic groups around the C-C bond in (CH3COOAg)2 and (CF3COOAg)2 dimers transforms into a hindered one in the (CHF2COOAg)2 dimer, and further into the existence of syn- and anti-structures divided by a high rotation barrier in the (CH2FCOOAg)2 dimer. In monomers, the ratio of the internal rotation barriers is similar. With increasing number of fluorine substitution for hydrogen atoms in dimers the Ag-Ag bond length is found to increase (2.79 Å, 2.81 Å, 2.83 Å, 2.84 Å) and the ring rigidity to simultaneously decrease in the acetate-triflouroacetate series
																								



3.
A QUANTUM CHEMICAL STUDY OF THE ELECTRONIC STRUCTURE OF SUBSTITUTED GERMOCANES

N. V. Alekseev, E. A. Chernyshev
Keywords: germocanes, quantum chemistry, AIM method, topological analysis
Pages: 442-450

Abstract >>
The PRIRODA (riDFT method, BLYP functional, hf.bas basis set) and Gaussian 98 (HF method, 6-311G(d,p) basis set) programs are used to calculate the spatial and electronic structures of a number of molecules of substituted germocanes with a general formula of R,R′Ge(XCH2CH2)2Y (where X = C, O, S, and Y = N, O, S). With the use of the AIM method the topological characteristics of Ge-Y donation bonds are calculated in these molecules. An analysis of the obtained data shows that up to the values of Ge-Y interatomic distances of ~2.7 Å these bonds can be considered as the intermediate type bonds. At Ge-Y distances of ~3.0 Å these bonds become ionic, therefore the Coulomb interaction between oppositely charged Ge and Y atoms mainly contributes to Ge-Y bonding.
																								



4.
An ab initio quantum chemical STUDY OF reaction mechanismS in the 22/CH3OH/KOH/DMSO system

E. Y. Larionova, N. M. Vitkovskaya, V. B. Kobychev, B. A. Trofimov
Keywords: vinyl ethers, vinylation, methoxide ion, mechanism, potassium hydroxide, dimethylsulfoxide, quantum chemical calculations
Pages: 451-458

Abstract >>
An ab initio quantum chemical study (MP2/6-311++G**//B3LYP/6-31+G*) of a number of possible interactions is performed for the gas phase system of acetylene-potassium hydroxide-dimethylsulfoxide(DMSO)-methanol and with regard to the solvent effect within the continuum model. Key structures in the vinylation reaction are shown to be methoxide ion complexes with the alkali metal hydroxide and acetylene molecules. The formation of these complexes results in the activation of the acetylene molecule and an increase in the nucleophilicity of the methoxide ion. In the 22/CH3OH/KOH/DMSO reaction system, a proton exchange between the acetylene molecule and the anionic nucleophile ([OH]- and [CH3O]-) is freely performed with the formation of systems with ethynide ions, whereas the thermodynamically preferable formation of vinyl alcohol or methyl vinyl ether is determined by a barrier of 20 kcal/mol
																								



5.
Density functional B3LYP and B3PW91 studies of the properties of four cyclic organodiboranes with tetramethylene fragments

M. Salavati-niasari, S.N. Mirsattari, M. Monajjemi, M. Hamadanian
Keywords: density functional theory, alkylborane, boranes, vibrational frequencies, natural bond orbital
Pages: 459-465

Abstract >>
Molecular structure and vibrational spectra of 1,2-tetramethylenediborane (B2C4H12), 1,2:1,2-bis(tetramethylene)diborane (B2C8H18), 1,1-tetramethylenediborane (B2C4H12) and 1,1:2,2-bis(tetramethylene)diborane (B2C8H18), have been studied using quantum computational density functional B3LYP and B3PW91 methods and 6-31G*, 6-31G** and 6-31++G** basis sets. Natural bond orbital analyses have been carried out to study in detail the nature of the B-C, C-C and B-H bonds in these molecules. This study showed that all these compounds are thermodynamically stable in the gas phase, but bicyclic structures are more stable than monocyclic structures.
																								



6.
ESTIMATION of absorption band CONTRIBUTION fOR overtones AND combined frequencies IN THE FINGERPRINT REGION FOR alkanes, nitriles, amines, AND nitroalkanes

A. I. Pavlyuchko, L. A. Gribov
Keywords: absorption spectra, anharmonic calculation, intensities of the overtones and combined frequencies, alkanes, nitriles, amines, nitroalkanes
Pages: 466-473

Abstract >>
In the anharmonic approximation the intensities of fundamental, overtone, and combined absorption bands are calculated in the range fr om 100 cm-1 to 4000 cm-1 for a series of alkanes, nitriles, amines, and nitroalkanes. The first and second derivatives of the molecular dipole moment are calculated by quantum chemical methods in the ab initio approximation using the MP2/6-31G(1d) basis set. Overtones and combined frequencies are found to make a significant contribution (5-20%) to the total absorption. The spectral distribution of this contribution depends on the molecular structure. For nitriles and amines significant absorption of the overtones and combined frequencies is observed in the same regions wh ere fundamental absorption bands characteristic of these compounds are located.
																								



7.
HYDROGEN BONDING EFFECT ON THE STRUCTURE AND VIBRATIONAL SPECTRA OF COMPLEMENTARY PAIRS OF NUCLEIC ACID BASES. I. ADENINE-URACIL

G. N. Ten, V. V. Nechaev, A. N. Pankratov, V. I. Baranov
Keywords: adenine, uracil, complementary pair, vibrational spectra, hydrogen bonding, interpretation
Pages: 474-482

Abstract >>
Vibrational spectra of the adenine-uracil complementary pair of nucleic acid bases (NAB) in the isolated state are calculated in the B3LYP/6-311++G(d,p) approximation and analyzed. The hydrogen bonding effect on frequency positions and intensities of normal vibrations of NAB pairs is shown in comparison with isolated uracil and adenine molecules.
																								



8.
NMR and DFT Study of chemical bonding of the titanyl ION in pentafluoro complexes (NH4)3TiOF5 and Rb2KTiOF5

V. Y. Kavun, S. G. Kozlova, I. A. Tkachenko, S. P. Gabuda
Keywords: titanyl ion, complex titanium oxyfluorides, 19F NMR spectra, chemical shift anisotropy, ion mobility, anion structure
Pages: 483-490

Abstract >>
19F NMR and DFT methods are used to study the electronic structure and chemical bonding of titanyl ions in pentafluoro titanyl complexes (NH4)3TiOF5 and Rb2KTiOF5. The experimental values of the anisotropy of 19F NMR chemical shifts (CSs) are shown to be consistent with the calculated parameters within the DFT method. At normal temperatures orientational disordering of octahedral [TiOF5]3- anions occurs, fluorine atoms steadily occupying cis- and trans-positions with respect to the 2- ion. In both complexes, trans-position is not fully occupied; the occupation ratio does not exceed ~4:0.9. When the temperature is decreased to 150 K, the value of the CS anisotropy of the fluorine atom resonance line in trans-position is found to be smaller than the dipole-dipole broadening, whereas the line from fluorine atoms in cis-positions transforms into an asymmetric broad line characterized by the triaxial anisotropy of the CS tensor. It is shown that the found anisotropy corresponds to violation of the axial symmetry of Ti-Fcis bonds because of strong delocalization of the electron density of Ti-O bonds in the titanyl ion.
																								



9.
ORGANIC RADICALS IN NATURAL APATITES ACCORDING TO EPR DATA: POTENTIAL GENETIC AND PALEOCLIMATIC INDICATORS

L. G. Gilinskaya
Keywords: organic radicals, vanadyl ion complexes, EPR spectra, natural marine apatites, paleoclimate
Pages: 491-500

Abstract >>
In a group of natural marine apatites Ca5(PO4)3(F, OH), organic H3, H2-R, HOHR, (CH3)2-R, and radicals are identified by EPR. The relation between the EPR spectra of the observed organic radicals, the valence form, and the structural location of impurity vanadium ions (V4+ (VO2+) on the Ca2+ II site or V5+ (VO4)3- → (PO4)3-) is established. The structure of organic radicals correlates with the type of organic matter in the sample under analysis: sapropelic or humic, depending on the climatic conditions of mineral genesis
																								



10.
EFFECT OF HYDROGEN BRIDGE GEOMETRY ON THE VIBRATIONAL SPECTRA OF WATER: THREE-PARAMETER POTENTIAL OF H BOND

Y. Y. Efimov
Keywords: liquid water, continuum model, hydrogen bond, fluctuation theory, geometry, potential, vibrational spectra
Pages: 501-508

Abstract >>
The ability of water molecules to form a three-dimensional network of hydrogen bonds basically determines both the intrinsic structure and unique properties of this liquid and also a character of interactions with other molecules. However, the dependence of the H bond energy on the geometry of its hydrogen bridge, namely on the ROO length and non-linearity, is unknown, i.e. the deviations of O-H group directions and the lone pair forming this bond from optimum ones (angles ϕ = H-OO and χ = -OO correspondingly). Even in computer simulation methods, the contribution of H bonds to the total interaction potential is not separated; that does not allow one to define unequivocally these bonds in a model and to analyze quantitatively the features of their networks. The purpose of this work is to fill in this gap by expressing the energy E through geometric parameters (R, ϕ, χ). The obtained solution quality is proved by an agreement between the distributions of OH vibrational frequencies (which are very sensitive to the H bond strength) calculated with its help and the shape of experimental spectra in a wide temperature range. Based on this, the distributions of H bond energies P(, T) and of their bend angles P(ϕ, T) and P(χ, T) are also calculated. It is shown that the main contribution to spectra is made by the shortest bonds with their lengths close to a minimum of the potential E(R). Thus, the low-frequency slope of a band corresponds to slightly bent H bonds, while the central part relates to also short but sufficiently nonlinear H bonds. LongH bonds are responsible for only well known high-frequency Walrafen's wing near 3620 cm-1. Moreover, these weak bonds are very strongly bent.
																								



11.
VOLUMETRIC PROPERTIES OF AQUEOUS SOLUTIONS OF AMINO ACIDS FROM THE SINGULAR TO CRITICAL TEMPERATURE

V. P. Korolev
Keywords: amino acids, aqueous solutions, volumetric properties
Pages: 509-517

Abstract >>
The partial volume of amino acids in aqueous solution is assumed to be zero for = 227 K (singular temperature) and = c (critical temperature). The literature data for (T) of ten amino acids at 278-328 K are reproduced by the two-parameter equation with a standard deviation of 0.06-0.16 cm3/mol. Only for asparagine and tryptophan the standard deviation exceeds 0.3 cm3/mol. In the case of glycine and alanine, the relation (T) in the high temperature range is obtained. is divided into contributions (/∂p)T and -T(/∂p)T. Their dependence on the temperature and amino acid nature is discussed. Positive values of (/∂p)T characterize amino acids as water structure breakers; however, the differentiation of compounds by this feature is not successful. The behavior of amino acids in aqueous solutions is compared with the behavior of urea
																								



12.
CHEMICAL AND STRUCTURAL TRANSFORMATIONS IN MANGANESE ALUMINUM SPINEL OF THE COMPOSITION Mn1.5Al1.5O4 DURING HEATING AND COOLING IN AIR

O. A. Bulavchenko, S. V. Tsybulya, P. G. Tsyrul'nikov, T. N. Afonasenko, S. V. Cherepanova, E. Y. Gerasimov
Keywords: high temperature X-ray diffraction, manganese aluminum systems, phase transformations
Pages: 518-524

Abstract >>
Single phase cubic spinel of the composition Mn1.5Al1.5O4 is synthesized. Its crystal structure refinement shows that 0.4Mn+0.6Al are in the octahedral sites and 0.7Mn+0.3Al are in the tetrahedral sites. High temperature X-ray diffraction is used to analyze Mn1.5Al1.5O4 behavior during heating and cooling in air. In a temperature range of 600C to 700C, initial spinel splits into layers, and the sample represents a two-phase system: cubic spinel Mn0.4Al2.4O4 and a phase based on β-Mn3O4. Above 900C the sample again turns into single phase cubic spinel. The role of oxidizing processes in the decomposition of Mn1.5Al1.5O4 caused by oxygenation and partial oxidation of Mn2+ to Mn3+ is shown. A scheme of structural transformations of manganese aluminum spinel during heating from room temperature and cooling from 950C is proposed.
																								



13.
CRYSTAL CHEMICAL FEATURES OF DAVYNE FROM TULTUI LAZURITE DEPOSIT (BAIKAL REGION)

A. N. Sapozhnikov
Keywords: cancrinite group, davyne structure, anion complexes, sulfate and sulfide forms of sulfur
Pages: 525-531

Abstract >>
The study shows that in the structure of davyne from the Baikal region sulfur exists in two forms: sulfate and sulfide. The presence of  disulfide makes it possible to remove charge imbalance in the chemical formula that emerged mainly because all sulfur was presented in the mineral only in the sulfate form. So far, sulfide sulfur has not been observed in the minerals of the davyne subgroup.
																								



14.
structure and luminescent properties of the cadmium(II) chloride complex with bis(benzotriazole-1-yl)methane

E. V. Lider, D. A. Piryazev, A. V. Virovets, L. G. Lavrenova, A. I. Smolentsev, E. M. Uskov, A. S. Potapov, A. I. Khlebnikov
Keywords: cadmium, bis(benzotriazole-1-yl)methane, complex, synthesis, crystal and molecular structure, luminescent properties
Pages: 532-536

Abstract >>
A procedure to synthesize a cadmium(II) chloride complex with bis(benzotriazole-1-yl)methane (L) of the composition [Cd2L(H2O)(C2H5OH)Cl4]n1.5nH2O is developed. The compound was studied by single crystal and powder X-ray diffraction. According to the single crystal X-ray data, the complex has a ribbon-polymer structure determined by bidentate bridging type coordination of L to cadmium(II) atoms by N(3) and N(3′) atoms. Tetramers of cadmium(II) atoms bonded by four bridging μ2- and two μ3-coordinated Cl atoms can be distinguished in the structure. The coordination polyhedron of cadmium(II) atoms is a distorted octahedron. The luminescent properties of L and dehydrated initial complex of the composition [Cd2L(H2O)(C2H5OH)Cl4]n are analyzed. It is shown that L has photoluminescence with λmax = 477 nm in the blue spectral region, and the complex has photoluminescence in the yellow-orange range with λmax = 577 nm at 300 K and λexc = 365 nm.
																								



15.
CRYSTAL STRUCTURE AND PHOTOLUMINESCENCE OF THE OPTICALLY ACTIVE COMPLEX [ZnL1Cl2], WHERE L1 = PYRAZOLYLQUINOLINE - A DERIVATIVE OF MONOTERPENOID (+)-3-CARENE

S. V. Larionov, Z. A. Savel'eva, R. F. Klevtsova, L. A. Glinskaya, E. M. Uskov, S. A. Popov, A. V. Tkachev
Keywords: synthesis, complex Zn(II), crystal and molecular structure, terpenoids, chirality, photoluminescence
Pages: 537-543

Abstract >>
The optically active complex [ZnL1Cl2] (I), where L1 = pyrazolylquinoline (a derivative of monoterpenoid (+)-3-carene) is obtained. Single crystals of compound I are grown and its crystal structure is determined from X-ray diffraction data (8 diffractometer, Kα radiation, 3031 Fhkl). The crystals of I are monoclinic; unit cell dimensions are: a = 8.4189(10) Å, b = 12.7194(11) Å, c = 9.7652(12) Å, β = 111.318(3), V = 974.14(19) Å3, Z = 2, dx = 1.499 g/cm3, space group P21. Complex I is composed of discrete mononuclear molecules. In coordination of Cl atoms and two N atoms of the bidentate cycling ligand L1, a distorted tetrahedral Cl2N2 polyhedron forms at zn. In the complex molecule, a fragment consisting of five-membered pyrazole and chelate rings, a five-membered carbocycle, and also two six-membered quinoline rings is almost planar. Solid complex I shows strong white photoluminescence at 300 K and λexc = 365 nm in the 400-700 nm range with λmax = 490 nm.
																								



16.
TWo CRYSTALLINE MODIFICATIONS OF [Au(dien)Cl](ReO4)2: SYNTHESIS, Structure, AND THERMAL PROPERTies

I. A. Baidina, E. V. Makotchenko, E. A. Shusharina, P. E. Plyusnin, A. I. Smolentsev, S. A. Gromilov
Keywords: gold, rhenium, complex, crystal chemistry, single crystal X-ray diffraction analysis, thermal analysis
Pages: 544-551

Abstract >>
Two crystalline modifications of a new [Au(dien)Cl](ReO4)2 complex are studied. The geometric characteristics of the [Au(dien)Cl]2+ complex cations are compared, and the way of additional coordination of gold atoms is considered. The thermal properties of the compound are studied in the inert and reducing atmospheres, and for the first time the possibility of the formation of Au0.1Re0.9 solid solution based on the hcp lattice of Re is shown.
																								



17.
MOLECULAR STRUCTURE OF N-METHYLBIS (2-HYDROXYETHYL)AMMONIUM HEXAFLUOROSILICATE AT 100 AND 298 K

M. G. Voronkov, A. A. Korlyukov, V. S. Fundamenskii, É. A. Zel'bst, M. Y. Antipin
Keywords: molecular structure, hexafluorosilicates, ammonium cations, shortened intermolecular contacts, single crystal X-ray diffraction, quantum chemical calculations
Pages: 552-557

Abstract >>
Two polymorphic modifications of N-methylbis(2-hydroxyethyl)ammonium hexafluorosilicate (AHFS) crystallize in monoclinic symmetry. The independent part of the unit cell of the low temperature modification contains two cations and an anion. The cell volume is two times smaller in the high temperature modification, the [SiF6]2- anion being disordered. In both modifications of methylbis(2-hydroxyethyl)ammonium hexafluorosilicate (HOCH2CH2)2HN+[SiF6]2- , the [SiF6]2- anion and the (22)2N+3 cation are linked by FH-O hydrogen bonds. The silicon atom polyhedron in the anion is a tetragonal bipyramid; the coordination polyhedron of the nitrogen atom in the cation is a tetrahedron
																								



18.
CRYSTAL STRUCTURE OF DL-SERINIUM TETRAFLUOROANTIMONATE(III)

A. A. Udovenko, R. L. Davidovich, L. A. Zemnukhova, E. V. Kovaleva, N. V. Makarenko
Keywords: serinium, fluoride antimony(III), crystal structure
Pages: 558-562

Abstract >>
For the first time the complex antimony(III) fluoride with a protonated cation of (C3H8NO3)SbF4 DL-serinium amino acid is synthesized and its crystal structure is studied. The structure of the new synthesized compound is compared to the structures of previously obtained and analyzed complexes of antimony(III) fluorides with glycinium and β-alaninium cations
																								



19.
CRYSTAL STRUCTURE OF BORon difluoride NAPHTHYLbutanedioNATE-1,3 (C10H7COCHCOCH3BF2). π-STACKING INTERACTION AND LUMINESCENCE

B. V. Bukvetskii, E. V. Fedorenko, A. G. Mirochnik, A. Y. Beloliptsev
Keywords: boron difluoride ?-diketonates, crystal structure, excimers, luminescence
Pages: 563-568

Abstract >>
The crystal structure and luminescent properties of boron difluoride 1-naphthyl-butandionate-1,3 (1) (C10H7COCHCOCH3BF2) are determined and analyzed. The molecules of compound 1 are packed in the crystal into infinite stacks due to π-stacking interactions. A feature of the structure of 1 is a fragment of four neighboring molecules, the π-systems of which participate in ππ interactions of different types: naphthylnaphthyl (head-to-head) and naphthylchelate (head-to-tail). The data of time resolved luminescent spectroscopy and quantum chemical computations show that in crystals and concentrated solutions of 1, one excimer structure occurs corresponding to the head-to-tail overlap.
																								



20.
NEW MOLECULAR COMPLEXES OF TRIMERIC PERFLUORO-ORTHO-PHENYLENE MERCURY WITH HETEROCYCLIC COMPOUNDS

N. A. Semenov, I. Y. Bagryanskaya, A. V. Alekseev, Y. V. Gatilov, E. Lork, R. Mews, G.-V. Roeschentaler, A. V. Zibarev
Keywords: heterocyclic compounds, molecular complexes, polymercury-containing macrocycles (anti-crowns), powder X-ray diffraction, single crystal X-ray diffraction
Pages: 569-574

Abstract >>
Slow evaporation in air of the solution of trimeric perfluoro-ortho-phenylene mercury (1) and 2,1,3-benzothiadiazole (2) in THF affords a complex 122H2O0.59 (3). A complex of 1 with di(tetrahydrofur-2-yl) ether (4; probably, a THF oxidation product) with a composition of 142 (5) is detected as a minor admixture to 3. The structure of complexes 3 and 5 is determined by single crystal XRD. In complex 3, a molecule of 1 participates in HgN and πFH-C interactions with one molecule of 2 and in the πFπH stacking interaction with another. Complex 5 is formed by HgO interactions with the participation of both heterocycles of a molecule of 4.
																								



21.
PACKING OF CHIRAL MOLECULES OF METAL TRIS-ACETYLACETONATES

P. A. Stabnikov, G. I. Zharkova, L. A. Komissarova, A. I. Smolentsev, S. V. Borisov
Keywords: chiral molecules, metal tris-acetylacetonates, low temperature thermochromism and phase transformations
Pages: 575-586

Abstract >>
The Cambridge Crystallographic Data Centre (CCDC) is searched to organize packings of metal tris-acetylacetonates (aa)3 (about 70 structures over the last 50 years). In all structures, planes with a hexagonal molecular environment are found. Three types of the nearest hexagonal environment are revealed in these planes with allowance for the chirality of molecules. Different superposition of these planes produces five types of packing of metal tris-acetylacetonates: α, β, γ, δ, and η. Spectrally pure Al(aa)3, Cr(aa)3, Mn(aa)3, and Fe(aa)3 complexes are synthesized and their solid solutions are studied. The effect of impurities on crystallization is established. A temperature range of 210 K to 100 K, in which we have previously detected thermochromism of metal β-diketonates is distinguished. In the same range, a symmetry change was previously found for Al(aa)3 and Mn(aa)3, however, Cr(aa)3 symmetry did not change in this temperature range. The ratios of components in solid solutions, at which low temperature symmetry change is observed in the complexes, are found experimentally. The relation between thermochromism and the symmetry change is discussed
																								



22.
STRUCTURE OF GALLIUM(III) MONOFLUORIDE PHTHALOCYANINATE: A QUANTUM CHEMICAL STUDY

S. G. Semenov, M. E. Bedrina
Keywords: gallium(III) phthalocyaninate, fluoride bridges, all-ecl. heptamer, all-ecl. polymer, structure, B3LYP/6-31G
Pages: 587-589

Abstract >>
The B3LYP/6-31G quantum chemical method is used to calculate the structural parameters of [F(PcGaF)7]-, [(PcGaF)6PcGa]+ heptamers and the (PcGaF) polymer of gallium(III) monofluoride phthalocyaninate. The eclipsed (ecl.) configuration (D4h point symmetry group) corresponds to the energy minimum of the [FGa(Pc)FGa(Pc)F]- dimer. The calculated equilibrium bond lengths in the central unit of all-ecl. heptamer (GaN 1.988 Å; GaF 1.933 Å) are similar to the bond lengths in the all-ecl. polymer (GaN 1.988 Å and GaF 1.940 Å) and to the respective single crystal X-ray diffraction parameters.
																								



23.
conformational analysis of methylboronic acid and its acyclic esters

O. Y. Valiakhmetova, S. A. Bochkor, V. V. Kuznetsov
Keywords: methylboronic acid, boric ester, conformer, quantum chemical calculations, potential energy surfaces, internal rotation barrier
Pages: 590-592

Abstract >>
With the use of RHF/6-31G(d) and 2/6-31G(d)//RHF/6-31G(d) semi-empirical (1) and non-empirical quantum chemical approximations conformational isomerization of methylboronic acid and its methyl, isopropyl, tert-butyl, and phenyl esters is studied. With the exception of the tert-butyl analogue, the potential energy surface of molecules in these compounds, is shown to contain three minima that correspond to planar and near-planar conformers: cis-cis, trans-trans, and cis-trans, with the latter being the main one. The minima are separated by two conformational isomerization barriers corresponding to the orthogonal arrangement of one of the (R) groups.
																								



24.
THEORETICAL STUDIES ON THE MECHANISM OF CHLORINATION REACTION OF TRICHLOROGERMYL ACRYLIC ACID

Y.Z. Fang, W.Y. Ma, J.H. Zhou, Y. Liu
Keywords: Germyl, crylic acid, density functional theory, potential energy calculations, transition state
Pages: 593-597

Abstract >>
The mechanism of the chlorination reaction of trichlorogermyl acrylic acid has been studied systematically using quantum chemistry methods. Geometries of reactants, transition states and products have been optimized at the B3LYP/6-311G(d,p) level. Vibrational frequencies, IR intensities and relative energies for various stationary points have been determined. The reaction pathways have been identified by intrinsic reaction coordinate (IRC) calculations. Theoretical analysis provides conclusive evidence that the process proceeds through two and three pathways for the first and second reaction steps, respectively.
																								



25.
CRYSTAL AND MOLECULAR STRUCTURE OF [RuNO(NO2)4OHCuPyn] HETEROMETALLIC COMPLEXES

G. A. Kostin, A. O. Borodin, N. V. Kuratieva
Keywords: copper, ruthenium, heterometallic complexes, nitroso complexes
Pages: 598-600

Abstract >>
Heterometallic complexes [RuNO(NO2)4OHCuPy2(H2O)] (I) and [RuNO(NO2)4OHuPy3] (II) are described structurally for the first time. In complex I, the ruthenium anion is coordinated to the copper atom by the bridging OH group and two bridging nitro groups; in complex II, by the bridging OH group and one bridging nitro group. Dimers are formed in the crystal lattice of complex II due to the interaction of the copper atom and the nitro group of the ruthenium anion in trans position to the bridging NO2 group.
																								



26.
[Rh(NH3)5Cl]WO4 CRYSTAL STRUCTURE

S. P. Khranenko, E. A. Shusharina, A. I. Smolentsev, P. E. Plyusin, S. A. Gromilov
Keywords: tungsten, rhodium, complex salt, crystal chemistry, single crystal X-ray diffraction analysis, thermal analysis
Pages: 601-604

Abstract >>
At T 150 K the crystal structure of [Rh(NH3)5Cl]WO4 is studied: a = 11.2374(4) Å, b = 8.4857(3) Å, c = 10.5326(3) Å, V = 1004.36(6) Å3, space group Pnma, Z = 4, dx = 3.117 g/cm3. In the structure, complex ions are bound by N-HO hydrogen bonds, with the shortest ones of 2.85-2.94 Å. Ionic packing is shown to be considered as rhombohedral with at ≈ 5.26 Å, αt ≈ 106. Thermal properties of the salt are studied in the hydrogen atmosphere. The product of thermal decomposition at 750C is a mixture of three solid solutions of RhxW1-x based on fcc, bcc, and hcp structures. All the obtained phases are nanocrystalline. The sizes of coherent scattering regions are 10-12 nm.
																								



27.
crystal structures of ruthenium(III) Cis and trans trifluoroacetylcetonate

N. B. Morozova, N. V. Kuratieva, K. V. Zherikova, T. N. Cheremisina
Keywords: ruthenium(III), trifluoroacetylacetone, cis and trans, synthesis, single crystal X-ray diffraction analysis
Pages: 605-609

Abstract >>
Single crystal X-ray diffraction analysis is used to determine the structures of ruthenium(III) cis and trans trifluoroacetylacetonate at a temperature of 150 K. The crystallographic data for cis-C15H12F9O6Ru are: a = 8.6562(3) Å, b = 12.6941(3) Å, c = 17.8776(5) Å, β = 93.129(1), P21/n space group, V = 1961.51(10) Å3, Z = 4, dx = 1.897 g/cm3, R = 0.0565. For trans C15H12F9O6Ru they are: a = 13.4060(3) Å, b = 14.5946(3) Å, c = 20.1316(4) Å, Pcab space group, V = 3938.85(14) Å3, Z = 8, dx = 1.890 g/cm3, R = 0.0840. Both structures are molecular and built of neutral molecules; the metal atom coordinates six atoms of oxygen of three ligands of β-diketone. The Ru-O distances in cis Ru(tfac)3 lie between 1.99 Å and 2.03 Å; in trans Ru(tfac)3, 1.99 Å and 2.02 Å. The molecules in the crystal are bonded only by van der Waals interactions; in the structures of the cis and trans forms, the six shortest RuRu distances lie within the limits of 7.601-8.656 Å and 7.326-7.714 Å respectively.
																								



28.
CRYSTAL AND MOLECULAR STRUCTURE OF THE [Nd2(H2O)8(C6F5COO)6]2H2O COMPOUND

L. A. Glinskaya, T. G. Leonova, R. F. Klevtsova, S. V. Larionov
Keywords: neodymium (III), binuclear complex, crystal and molecular structure, pentafluorobenzoate ions
Pages: 610-615

Abstract >>
A compound with the composition Nd(C6F5COO)3H2O (I) is prepared. Single crystals are grown, and their single crystal XRD analysis of the Nd2(H2O)8(C6F5COO)6]2H2O (II) compound is performed. The crystals are triclinic: a = 7.693(2) Å, b = 9.394(2) Å, c = 18.203(4) Å, α = 81.91(3), β = 84.41(3), γ = 88.97(3), Z = 1, dx = 2.223 g/cm3. The structure is composed of symmetrical molecules of the binuclear [Nd2(H2O)8(C6F5COO)6] complex and crystallization water molecules. The 6F5COO ligands are monodentate and tridentate bridging- chelating, which results in a closure of two four-membered chelate cycles NdO2C and a four-membered metal cycle Nd2O2. The NdO9 polyhedron is a distorted one-capped tetragonal antiprism.
																								



29.
MOLECULAR STRUCTURE OF (4Z)-{[(1R,6S)-7,7- DIMETHYL-2-OXO-3-OXABICYCLO [4.1.0]HEPT-4-EN- 4-YL]METHYLENE}-2-PHENYL-1,3-OXAZOL-5(4)-ONE

V. G. Kasradze, E. V. Salimova, F. Z. Galin, O. S. Kukovinets, Z. A. Starikova, M. Y. Antipin
Keywords: oxazolone, formyl enol lactone derivative of ketocaronic acid, Erlenmeyer reaction, single crystal X-ray diffraction analysis
Pages: 616-619

Abstract >>
The (4Z)-{[(1R,6S)-7,7-dimethyl-2-oxo-3-oxabicyclo[4.1.0]hept-4-en-4-yl]methylene}-2-phenyl-1,3-oxazol-5(4)-one compound is synthesized and its molecular structure is determined.