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Journal of Structural Chemistry

2009 year, number 3

1.
QUANTUM-CHEMICAL STUDY OF STRUCTURIZATION OF WATER IN THE CAVITY OF CUCURBIT[6]URYL

A. N. Maslii, T. N. Grishaeva, A. M. Kuznetsov, V. V. Bakovets
Keywords: cucurbit[6]uryl, cavitand, PBE density functional method, water clusters, the structure of water
Pages: 413-418

Abstract >>
Structurization of water in the cavity of cucurbit[6]uryl was studied using the highly effective PRIRODA quantum-chemical program package, the PBE functional, and the TZ atomic basis. The structural and energy characteristics of the formation of small water clusters in the cavitand void were calculated. The maximum possible number of molecules in the void was found to be six.



2.
INTRAMOLECULAR RESONANCE AS A CATALYTIC FACTOR

L. ??. Gribov, V. I. Baranov
Keywords: chemical transformations, resonance, catalysis
Pages: 419-424

Abstract >>
It was shown that the resonance mixing of states on large molecules can increase the probability of reaction. This effect is similar to a decrease in the activation threshold or the action of an external catalyst.



3.
SIMULATION OF GAS DIFFUSION IN POROUS LAYERS OF VARYING STRUCTURE

A. V. Anikeenko, N. N. Medvedev, M. K. Kovalev, M. S. Melgunov
Keywords: computer simulation, random wanderings, gas diffusion, mesoporous mesophase materials, porous layers, residence time in a layer, gas chromatography
Pages: 425-432

Abstract >>
Gas diffusion in porous layers of varying structure was simulated numerically. Mesoporous mesophase material (MMM) and silica gel layers were studied. The former were a set of ordered cylinders; the latter were disordered packings of spheres. The average residence time of a molecule in a layer (return time) and dispersion of this time in relation to the layer depth were calculated. For the same porosity and specific surface of layers, the average return time is independent of the pore structure and increases with the layer depth as a linear function. This is the consequence of the general theoretical result, according to which the duration of molecule wandering in a pore depends only on the ratio of the pore volume to the section area of its windows. Dispersion of the wandering time is sensitive to the pore structure; it is slightly smaller for regular pores than for a complex pore system. The functional dependence of return time dispersion on the layer depth is the same for different layers (the cubic root of dispersion changes with the layer depth as a linear function). This work helps us to understand recent experimental data, which showed that using MMM for gas chromatographic columns increased the efficiency of the latter compared with other columns based on silicon oxide.



4.
1Í nmr refinement of the structure of the guest sublattice and molecular dynamics in the ultrathin channels of [Zn2(C8H4O4)2(C6H12N2)]·n(H3C)2NCHO


Keywords: organometal sorbent, dimethyl formamide, molecular mobility, 1Í NMR
Pages: 443-450

Abstract >>
Localization and molecular mobility of the ligands ([C8H4O4]2+ and [C6H12N2]0) of the host lattice and (CH3)2NCHO dimethyl formamide guest molecules in the inclusion compound [Zn2(C8H4O4)2(C6H12N2)]·
n(H3C)2NCHO were studied on the basis of 1H NMR data. At room temperature, the longest axes of the dimethyl formamide guest molecules are ordered in parallel to the Ñ4 symmetry axes, and the symmetry planes of these molecules are disordered, while preserving the tetragonal crystal system of the inclusion compound. At lower temperatures, a phase transition takes place in view of the ordering in the guest sublattice.



5.
Analysis of Fe−Si layered structures by reflected electron energy loss spectroscopy and inelastic scattering cross-section

A. S. Parshin, G. A. Aleksandrova, S. N. Varnakov, S. G. Ovchinnikov
Keywords: reflected electron energy loss spectroscopy, inelastic scattering cross-section, mean length of the inelastic free path of an electron
Pages: 451-455

Abstract >>
This paper reports on our study of the formation of an interface of layered structures in the Fe-Si system by reflected electron energy loss spectroscopy (REELS). Quantitative element analysis was performed using the product of the mean length of the inelastic free path by the inelastic scattering cross-section of electrons. It is shown that the Fe-Si interface is quite uniform.



6.
Electronic structure and specroscopic properties of norfloxacin, enoxacin, and nalidixic acid


Keywords: fluoroquinolones, antibacterial activity, X-ray photoelectron spectroscopy, electronic structure, UV absorption spectra, luminescence, quantum-chemical calculation, Mulliken charges
Pages: 456-460

Abstract >>
The X-ray photoelectron spectra (XPS) of the core electrons of the carbon, oxygen, nitrogen, and fluorine atoms of antibiotics from the class of quinolones (nalidixic acid, norfloxacin, and enoxacin), having different antibacterial activities, were measured and interpreted. The integrated intensities of the π-π* and n-π* transition bands in the absorption spectra of the compounds were analyzed. The maxima of the luminescence spectral bands are given along with the lifetimes of the excited states and quantum yields of the protolytic forms of the compounds in aqueous media. The XPS data were compared with the Mulliken charges on heteroatoms obtained by quantum-chemical calculations.



7.
X-RAY PHOTOELECTRON SPECTROSCOPIC STUDIES OF THE CHARGED STATE OF 3d METAL IONS IN CuCr1-xVxS2 (x = 0-0.4)

L. N. Mazalov, V. V. Sokolov, N. A. Kryuchkova, E. I. Vovk, I. Y. Filatova, G. M. Abramova
Keywords: cation-substituted disulfides, X-ray photoelectron spectroscopy, Auger spectroscopy
Pages: 461-467

Abstract >>
The charged state of the 3d metal ions in layered cation-substituted disulfides CuCr1-xVxS2 was studied by X-ray photoelectron spectroscopy. An analysis of the energy positions and structure of the Cu2p3/2 and Cr2p3/2 X-ray photoelectron lines showed that the corresponding polycrystalline samples of CuCr1-xVxS2 contained mixed-valence chromium and copper ions. It was shown that the charged states of chromium and copper ions depended on the concentration of vanadium cations (x). The presence of mixed-valence Cu1+ and Cu2+ ions in CuCr1-xVxS2 may be correlated with the crystal structure of the corresponding layered disulfides.



8.
THERMODYNAMIC PERTURBATION THEORY OF SIMPLE LIQUIDS

Y. T. Pavlyukhin
Keywords: thermodynamic perturbation theory, simple liquids
Pages: 468-477

Abstract >>
It was proven that after averaging over the canonical Gibbs ensemble, the mean perturbation energy was singled out of the classical partition function before the expansion in a series of perturbation theory. Therefore, the term that formally coincides with first order perturbation theory in a decomposition of the Helmholtz free energy bears no relationship to perturbation theory. Then the proper series of the thermodynamic perturbation theory always starts with a second order infinitesimal. Therefore, the well-known condition of applicability of the thermodynamic perturbation theory, "…the requirement that the perturbation energy per particle be small compared with Ò…" (L. D. Landau and E. M. Livshits, Statistical Physics, Vol. V, Pt. I), can be substantially weakened. The most important factor for applicability of thermodynamic perturbation theory is the value of many-particle correlations in an unperturbed system, but not the smallness of the perturbation potential.



9.
Thermodynamic analysis of the structure of aqueous solutions of Ñ12−Ñ18 hydrocarbons

Y. A. Mirgorod
Keywords: Ñ5-C9 and Ñ12-C18 hydrocarbons, micelles, thermodynamic cycles, hydrophobic interaction, bistable structure
Pages: 478-481



10.
PARAMETERS OF THE TEMPERATURE DEPENDENCE OF THE RATE OF MAGNETIC RELAXATION OF PROTONS IN WATER AND ITS SOLUTIONS INCLUDING SEAWATER

N. A. Melnichenko, A. S. Vyskrebentsev
Keywords: solutions, seawater, temperature dependence, relaxation, dynamic properties, structure of water
Pages: 482-491

Abstract >>
The results of measurements of the temperature dependence of the relaxation rate (1/Ò1) of protons in seawater with 35‰ salinity and salt solutions with different concentrations at temperatures from -22°C to +120°C are presented. The possibility of approximating the temperature dependence of the magnetic relaxation rate by different functions in pure water, seawater, and solutions of the salts of the latter was studied. The parameters of this dependence and their variation under the influence of salt components are given. The least mean square deviation was obtained, and the best convergence was determined according to the statistical criteria for aqueous electrolytes of moderate concentrations for the function in the form of the sum of exponentials, in which the number of terms depended on the solution concentration. It is shown that the parameters of the thermal dependence of the relaxation rate represented by different functions can be used in combination for studying the dynamic properties of the solutions of low and moderate concentrations.



11.
RECONSTRUCTIVE PHASE TRANSITIONS OF OXYGEN OCTAHEDRAL STRUCTURES


Keywords: crystal chemistry, phase transitions, ferroelectrics, oxide systems
Pages: 492-496

Abstract >>
Reconstructive phase transitions and their conditions in perovskite, ilmenite, pyrochlore, and other structures were considered on the basis of the experimental structural data on oxide compounds. It is shown that such transitions depend on the pressure, temperature, chemical composition, and defective structure.



12.
HIGH-TEMPERATURE X-RAY STUDY OF THE FORMATION and DELAMINATION OF MANGANESE−ALUMINA SPINEL Mn1.5Al1.5O4


Keywords: high-temperature X-ray diffraction, manganese?alumina systems, phase transformations
Pages: 497-501

Abstract >>
The behavior of the manganese−alumina system with Mn:Al = 1:1 on heating in air and vacuum was studied. The starting samples were mixtures of β-Mn3O4, α-Mn2O3, and γ-Al2O3. On heating to 950°C in air, the samples were partially oxidized into α-Mn2O3, and corundum α-Al2O3 formed along with mixed manganese−alumina cubic spinel, whose composition was close to Mn2AlO4. In vacuum at 1200°C, the starting sample with a ratio of Mn:Al = 1:1 transformed into the manganese−alumina spinel Mn1.5Al1.5O4, which retained its cubic structure after slow cooling in vacuum. When cooled in air, this solid solution delaminated, and a nanocrystalline Mn2.8Al0.2O4 phase formed, whose structure was β-Mn3O4 type tetragonal spinel.



13.
CRYSTAL STRUCTURE AND PROPERTIES OF [M(NH3)5Cl](NO3)2, (M = Ir, Rh, Ru)


Keywords: iridium, rhodium, ruthenium, chloropentammines, nitrates, X-ray analysis, X-ray phase analysis
Pages: 502-507

Abstract >>
The crystal structures of compounds from the series [M(NH3)5Cl](NO3)2, (M = Ir, Rh, Ru) were described. The compounds crystallized in the tetragonal crystal system, space group I4, Z = 2. Crystal data for [Ir(NH3)5Cl](NO3)2 (I): a = 7.6061(1) Å, b = 7.6061(1) Å, c = 10.4039(2) Å, V = 601.894(16) Å3, ρcalc =
2.410 g/cm3, R = 0.0087; [Rh(NH3)5Cl](NO3)2 (II): a = 7.5858(5) Å, b = 7.5858(5) Å, c = 10.41357(7) Å, V =
599.24(7) Å3, ρcalc = 1.926 g/cm3, R = 0.0255; [Ru(NH3)5Cl](NO3)2 (III): a = 7.5811(6) Å, b = 7.5811(6) Å, c = 10.5352(14) Å, V = 605.49(11) Å3, ρcalc = 1.896 g/cm3, R = 0.0266. The compounds were defined by IR spectroscopy and XRPA and thermal analyses.



14.
CRYSTAL STRUCTURE AND LUMINESCENCE OF EUROPIUM(III) ACRYLATE

B. V. Bukvetskii, N. V. Petrochenkova, À. G. Mirochnik
Keywords: crystal structure, europium(III), acrylate, luminescence
Pages: 508-512

Abstract >>
The atomic structure of europium acrylate crystals [Eu2(Acr)5OH·3H2O]·2(0.5H2O) was studied by X-ray analysis (a = 24.360(3) Å, b = 18.466(2) Å, c = 8.5818(9) Å, β = 96.087(2)°, space group C2/c, Z = 6, ρcalc = 2.036 g/cm3). The crystal structure involves chains of binuclear [Eu2(C3H3O2)5OH·3H2O] molecules, running infinitely in the [101] direction and having pairs of C9H9EuO7H2O molecules alternating with C6H6EuO4OH·2H2O molecules that link the pairs. The infinite chains are linked by hydrogen bonds and van der Waals interactions. The thermal behavior of luminescence of the europium(III) complex is discussed.



15.
CRYSTAL STRUCTURES OF PYRIDINE-4-ALDEHYDE THIOSEMICARBAZONE PERCHLORATE AND TRIFLUOROMETHANE SULFONATE

A. I. Smolentsev, L. G. Lavrenova, V. N. Elokhina, A. S. Nakhmanovich, L. I. Larina
Keywords: perchlorate, triflate, pyridine-4-aldehyde thiosemicarbazone, synthesis, XRD, NMR spectra
Pages: 522-526

Abstract >>
The new salts of pyridine-4-aldehyde thiosemicarbazone: perchlorate (I) and trifluoromethane sulfonate (II) HN+C5H4-CH=N-NH-C(S)-NH2·X- (X = ClO4, CF3SO3) were synthesized and studied by IR and NMR spectroscopy and X-ray diffraction analysis. The compounds were synthesized by a reaction of pyridine-4-aldehyde thiosemicarbazone with chloric or trifluoromethane sulfonic acid, respectively. Compound I crystallized in the triclinic crystal system, space group P-1, a = 6.8691(2) Å, b = 9.5406(4) Å, c =
9.6348(4) Å, α = 78.838(1)°, β = 77.618(1)°, γ = 69.661(1)°, Z = 2. Compound II crystallized in the monoclinic crystal system, space group P21/c, a = 7.3149(8) Å, b = 11.9830(16) Å, c = 15.143(2) Å, β = 96.949(4)°, Z = 4. The structures are formed by hydrogen-bonded ions. Moreover, the cations are linked in "dimmers" due to the weak N-H…S hydrogen bonds.



16.
Crystal structures of ethyl-4-(5-bromo-2-hydroxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate and ethyl-1-methyl-15-oxo-2-oxa-14,16-diazatetracyclo [11.3.1.03.12.06.11]heptadeca-3,5,7,9,11-pentaene-17-carboxylate

M. M. Kurbanova, A. V. Kurbanov, R. K. Askerov, M. A. Allakhverdiev, V. N. Khrustalev, A. M. Magerramo
Keywords: X-ray analysis, crystal structure, ethyl-4-(5-bromo-2-hydroxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate, ethyl-1-methyl-15-oxo-2-oxa-14,16-diazatetracyclo[11.3.1.03.12.06.11]· heptadeca-3,5,7,9,11-pentaene-17-c
Pages: 527-531

Abstract >>
The crystal structures of ethyl-4-(5-bromo-2-hydroxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine- 5-carboxylate and ethyl-1-methyl-15-oxo-2-oxa-14,16-diazatetracyclo[11.3.1.03.12.06.11]heptadeca-3,5,7, 9,11-pentaene-17-carboxylate were determined by XRD, and the conformations of their structures were determined.



17.
MOLECULAR AND CRYSTAL STRUCTURE OF QUINOLINE-2-ALDEHYDE THIOSEMICARBAZONE

P. N. Bourosh, M. D. Revenko, M. Gdaniec, E. F. Stratulat, Y. A. Simonov
Keywords: quinoline-2-aldehyde thiosemicarbazone, synthesis, structure, configuration, crystal structure
Pages: 532-535

Abstract >>
The molecular and crystal structure of quinoline-2-aldehyde thiosemicarbazone is determined. The thiosemicarbazide fragment has cis-arrangement of terminal nitrogen atoms relative to the central N-C bond. The structure is based on a centrosymmetric dimer formed by hydrogen bonds between NH groups and sulfur atoms of thiosemicarbazide fragments of the neighboring molecules. In the crystal, the dimers are joined with each other through a system of hydrogen bonds and intermolecular π-π interactions.



18.
PHOTOELECTRON SPECTROSCOPY AND DIFFRACTION OF SURFACE NANOSCALE NbO/Nb(110) STRUCTURES

M. V. Kuznetsov, A. S. Razinkin, E. V. Shalaeva
Keywords: XPS, XPD, STM, surface, niobium, niobium oxide, surface structures
Pages: 536-543

Abstract >>
X-ray photoelectron spectroscopy and diffraction (XPS and XPD) are applied to analyze oxygen-induced surface structures on the Nb(110) face formed due to oxygen segregation from the crystal bulk on thermal annealing to 2000 K in vacuum and/or oxygen adsorption in situ at temperatures above 1100 K. The Nb3d, O1s electronic states and valence band spectra of the NbOx/Nb(110) surface are studied by XPS, and the results are compared with data for NbO, NbO2, and Nb2O5 oxides. It is shown that niobium atoms entering the composition of surface oxide structures on Nb(110), from the standpoint of the nearest environment and chemical bond, are similar to metal states in NbO. The NbOx layer thickness is estimated to be 0.5 nm. Two chemically inequivalent oxygen states are distinguished on Nb(110), which are, presumably, atomic chemisorbed oxygen on the parts of the clean surface of the Nb monolayer with hexagonal packing and oxygen in the composition of NbOx-like linear clusters on Nb(110). A model of the NbOx/Nb(110) surface takes into account a distortion of the structure of NbOx clusters: a periodic vertical shift of metal atoms in Nb-chains and changes in Nb-O bond angles.



19.
NEW SUPERCONDUCTORS BASED ON (Ca, Sr, Ba)Fe2As2 TERNARY ARSENIDES: SYNTHESIS, PROPERTIES, AND SIMULATION

A. L. Ivanovskii
Keywords: ternary arsenides, superconductivity, synthesis, structure, properties, simulation
Pages: 560-572

Abstract >>
The discovery in 2008 of superconducting transition (Tc ~ 38 K) for BaFe2As2 arsenide doped with potassium has stimulated works on synthesis, studies of structural and electromagnetic properties, and simulation of this and similar materials. A brief review of the current state of studies on novel superconducting arsenides in the mentioned aspects is presented.



20.
CHEMICAL BONDING IN LaFeAsO, SrFe2As2, AND LiFeAs: BASIC PHASES OF NEW 18-56 K SUPERCONDUCTORS

I. R. Shein, À. L. Ivanovskii
Keywords: FeAs superconductors, band structure calculations, chemical bonding
Pages: 573-576

Abstract >>
Based on FLAPW-GGA calculations, a comparative study of the features of interatomic interactions in LaFeAsO, SrFe2As2, and LiFeAs layered crystals (basic phases of new 18-56 K superconductors) is carried out.



21.
PREDICTION OF THE VAPORIZATION ENTHALPY BASED ON MODIFIED RANDIC INDICES. I. MONOHYDRIC ALCOHOLS

E. L. Krasnykh
Keywords: vaporization enthalpy, topological index, connectivity index, alcohols, energy of hydrogen bonds, QSPR
Pages: 577-581

Abstract >>
The vaporization enthalpy of monohydric alcohols with different structures under normal conditions is calculated using a modified Randič method with an error comparable to the experimental one. The energy of hydrogen bonds in alcohols is determined and shown to be constant and independent on the alcohol structure.



22.
RADIOGRAPHIC STUDY OF THE PHASE FORMATION PROCESS IN OBTAINING KNbO3

Y. A. Kuprina, P. Y. Teslenko, N. B. Kofanova, M. F. Kupriyanov, Y. V. Kabirov
Keywords: KNbO3, perovskite, solid phase synthesis, stoichiometry
Pages: 582-586

Abstract >>
Instability in the formation of KNbO3 with perovskite structure is complicated by its structural instability. The structural instability accounts for the existence of phases different in their symmetry and cell parameters (rhombic, tetragonal, and cubic) at room temperature.



23.
CRYSTAL STRUCTURE OF BINARY MOLYBDATE Pr2Hf3(MoO4)9

B. G. Bazarov, V. G. Grossman, R. F. Klevtsova, A. G. Anshits, T. A. Vereshchagina, L. A. Glinskaya, Y. L. Tushinova, K. N. Fedorov, Z. G. Bazarova
Keywords: thallium, praseodymium, hafnium, binary molybdates, kosnarite, crystal structure
Pages: 587-590

Abstract >>
Crystals of binary praseodymium and hafnium molybdate of Pr2Hf3(MoO4)9 composition are grown by solution-melt crystallization under spontaneous nucleation conditions. By the X-ray diffraction data (X8 Apex automated diffractometer, ÌîKα radiation, 2262 F(hkl), R = 0.0170) its composition and crystal structure are determined. Parameters of the trigonal unit cell are: a = b = 9.8001(1) Å, c = 58.7095(8) Å, V = 4883.15(10) Å3, Z = 6, space group R3c. The crystal structure is composed of three types of polyhedra: ÌîÎ4 tetrahedra, HfO6 octahedra, and nine-vertex PrO9. All three types of polyhedra are bonded among themselves by common oxygen vertices of bridging ÌîÎ4 tetrahedra forming an openwork three-dimensional structure.



24.
CRYSTAL STRUCTURE of (5-METHYLCYCLOPENTADIENYL)-(1,5-CYCLOOCTADIENE) IRIDIUM(I)

K. V. Zherikova, N. B. Morozova, I. A. Baidina
Keywords: iridium(I), 1,5-cyclooctadiene, 5-methylcyclopentadiene, synthesis, X-ray diffraction analysis
Pages: 591-594

Abstract >>
XRD is used to determine the structure of Cp′Ir(cod) at a temperature of 150(2) K. Crystallographic data for C14H19Ir are: a = 10.8272(5) Å, b = 9.7746(4) Å, c = 10.9180(5) Å, β = 97.3310(10)°, monoclinic symmetry, space group P21/n, V = 1146.02(9) Å3, Z = 4, dcalc= 2.199 g/cm3, R = 0.0246. The structure is molecular, built of neutral molecules. The metal atom coordinates carbon atoms of two cyclic ligands:
5-methylcyclopentadienyl-ion (Cp′) and 1,5-cyclooctadiene (cod). Five Ir-CCp′ distances lie in the range of 2.21-2.28 Å; four Ir-Ccod distances differ insignificantly, and their average value is 2.114(13) Å. The Ñ11Ñ12Ñ13Ñ14Ñ15 and C1C2C5C6 planes of ligand fragments are almost parallel, and the angle between normals is 1.9°. In the crystal, molecules are bonded only by van der Waals interactions; in the structure, the eight shortest Ir…Ir distances are in the range of 5.608-7.257 Å.



25.
CRYSTAL STRUCTURE OF (ACETYLACETONATO)(DICARBONYL)IRIDIUM(I)

K. V. Zherikova, N. V. Kuratieva, N. B. Morozova
Keywords: iridium(I), acetylacetone, carbonyl, XRD
Pages: 595-597

Abstract >>
The structure of Ir(CO)2(acac) is determined by XRD at room temperature. Crystallographic data for C7H7IrO4 are: a = 6.4798(5) Å, b = 7.7288(5) Å, c = 9.1629(10) Å, α = 105.738(2)°, β = 90.467(3)°, γ = 100.658(2)°, space group P1 V= 433.24(6) Å3, Z = 2, dcalc = 2.662 g/cm3, R = 0.0167. The structure is built of isolated mononuclear molecules. The central iridium atom has a square coordination environment formed by two oxygen atoms that belong to the acetylacetonate ligand and two carbon atoms of carbonyl groups. The average Ir-O and Ir-C bond lengths are 2.045(3) Å and 1.832(6) Å respectively. Molecules are stacked in such a way that the planes of coordination squares turn out to be parallel to the Ir…Ir distances between the nearest neighbors in the stack of 3.242 Å and 3.260 Å.



26.
STRUCTURE OF [RuNO(NH3)3(H2O)Cl](NO3)2, PRODUCT OF INTERACTION BETWEEN HYDROXONITROTRIAMMINENITROSORUTHENIUM(II) CHLORIDE AND NITRIC ACID

V. A. Emel'yanov, E. V. Kabin, I. A. Baidina
Keywords: ruthenium, nitroso complexes, ammine complexes, X-ray diffraction analysis, crystal chemistry
Pages: 598-601

Abstract >>
The structure of the product formed on boiling [RuNO(NH3)3(NO2)(ÎH)]Cl·0.5H2O in 3 M HNO3 is determined by XRD. The crystals belong to monoclinic symmetry. Crystallographic data for H11ClN6O8Ru are: a = 13.7924(4) Å, b = 6.9114(2) Å, c = 12.3577(4) Å, β = 111.863(1)°, V = 1093.27(6) Å3, Z = 4, dcalc = 2.185 g/cm3, space group Cc. The structure is built of complex [RuNO(NH3)3(H2O)Cl]2+ cations and anions NO-3. The compound is studied by IR spectroscopy and X-ray phase analysis.



27.
CRYSTAL STRUCTURE OF CALCIUM cis(N)-bis(IMINODIACETATO)CHROMATE(III) NONAHYDRATE Ca[Cr(Ida)2]2·9H2O

M. Zabel, V. I. Pavlovskii, A. L. Poznyak
Keywords: crystal structure, bis(iminodiacetato)chromate(III) ion, calcium salt
Pages: 602-604

Abstract >>
In the crystals of [Ca(H2O)5][Cr(Ida)2]2·4H2O (triclinic symmetry, a = 10.1056(10) Å, b = 13.0077(11) Å, c = 13.1185(13) Å, α = 70.186(11)°, β = 81.248(11)°, γ = 78.996(11)°, Z = 2, space group P1) cyclic centrosymmetric tetramers are present. In them calcium ions are bonded to oxygen atoms of the carboxyl groups of two octahedral complex cis(N)-[Cr(Ida)2]- ions (Ida is the iminodiacetic acid anion). The Î atoms of five water molecules complete the Ñà atom environment to a distorted pentagonal bipyramid. Isolated [Cr(Ida)2]- ions of a similar structure neutralize the positive charge of tetramers.



28.
STRUCTURE OF 2-CHLORO-3-PHENYLBENZOIC ACID

V. P. Boyarskiy, M. S. Fonari, K. Suwinska, Y. A. Simonov
Keywords: polychlorobiphenyls, carbonylation, aromatic carbonic acids, synthesis, crystal structure
Pages: 605-607

Abstract >>
The carbonylation reaction of 2,3-dichlorobiphenyl proceeds with a substitution of the chlorine atom in position 3 and results in the formation of 2-chloro-3-phenylbenzoic acid. The structure of this acid is revealed by single crystal XRD. It is determined by steric interactions of substituents in positions 2,4,2′, and 6′, a stable carboxyl supramolecular synthon, and weak interactions with the participation of the carbonyl oxygen atom and the chlorine atom.



29.
CRYSTAL STRUCTURE OF BROMOALKYL DERIVATIVES of 6-METHYL-URACIL AND ISOCYANURIC ACID

Y. K. Voronina, L. F. Saifina, E. S. Romanova, O. A. Lodochnikova, I. A. Litvinov
Keywords: XRD, pyrimidinophanes, isocyanurate, C=O…Br-interactions, C-H…O-interactions
Pages: 608-611

Abstract >>
Single crystal XRD is used to study the crystal structure of 1-(4-bromobutyl)-3,6-dimethyluracil and 1,3-dimethyl-5-(5-bromopentyl)-isocyanurate in comparison with structurally similar compounds studied previously. It is shown that unlike macrocyclic compound, for which the crystal structure is determined by the presence of the stacking effect, in the crystals of their artificial precursors stacking interactions are not observed. For 1-(4-bromobutyl)-3,6-dimethyluracil, C-H…O interactions and Ñ=O…Br interactions for 1,3-dimethyl-5-(5-bromopentyl)-isocyanurate are found.