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Journal of Structural Chemistry

2008 year, number 3

1.
NEW APPROACH TO THE CORRELATION PROBLEM: ELECTRON INTERACTION POTENTIAL AS A VARIABLE IN SOLVING THE MANY-PARTICLE SCHRODINGER EQUATION

V. M. Tapilin
Keywords: electron-electron correlations, ionization energies of helium-like ions, generalized Hartree-Fock equations
Pages: 407-414

Abstract >>
The many-electron wave function is represented as the product of the wave function of the independent particles and the function that depends only on the value of the interelectron interaction potential. The function defines the electron correlation effects; a standard linear differential equation was derived to define the function. The equation depends on the functions of independent particles; a generalization of the Hartree-Fock equations including electron correlation was obtained for these functions. The total energy calculation of two-electron ions shows that even solving an ordinary differential equation for the function of independent particles represented by the functions of noninteracting electrons leads to higher accuracy than the one achieved in the Hartree-Fock theory.
																								



2.
QUANTUM-CHEMICAL ANALYSIS OF THE NUCLEOPHILIC SUBSTITUTION OF THE BROMINE ATOM BY THE CYANO GROUP AT THE SP-HYBRIDIZED CARBON ATOM IN THE METHYLBROMOACETYLENE MOLECULE

Y. L. Frolov, A. V. Vashchenko, V. I. Smirnov, A. G. Malkina, B. A. Trofimov
Keywords: ab initio quantum-chemical calculations, nucleophilic substitution, metallocomplex catalysis, substituted acetylenes
Pages: 415-418

Abstract >>
This paper reports on our quantum-chemical analysis of the nucleophilic substitution of the bromine atom by the cyano group in the reaction of methylbromoacetylene with copper cyanide. According to calculations, the reaction can form a four-membered ring containing a copper atom.
																								



3.
HYDROGEN BOND AND THE STRUCTURES OF 2-, 3- AND 4-BIPHENYLMETHANOLS

L. M. Babkov, N. A. Davydova, K. E. Uspenskii
Keywords: IR spectrum, structure, hydrogen bond, -complex, simulation, density functional theory, triclinic modification, monoclinic modification, glass phase, liquid
Pages: 419-426

Abstract >>
Density functional theory (B3LYP/6-31G*) is applied to calculate structures, energy, dipole moment, polarizability, frequencies of normal vibrations in the harmonic approximation and intensities in vibrational spectra of 2-, 3-, and 4-biphenylmethanol molecules and their H-complexes that can form in crystalline, amorphous, and liquid phases. Based on the analysis of simulation results, the effect of the position of a methanol group in the molecule on its vibrational spectrum is discussed. The structure forming role of a hydrogen bonds in biphenylmethanols and the possibility of realization of two polymorphic modifications in 2-biphenylmethanol are stated. These modifications are: metastable monoclinic, in which each of four molecules of the unit cell is a link of a chain -associate; and stable triclinic, in which four molecules of the unit cell organize an -complex in the form of a cyclic tetramer. It is found that crystalline samples of 3- and 4-biphenylmethanols consist of chain -associates. A glass-like sample of 2BPhM being a mixture of -complexes consisting of cyclic tetramers and chain associates contains crystalline nuclei of triclinic and monoclinic polymorphous modifications in the supercooled state. In a liquid sample of 2BPhm, chain -associates and free molecules are realized.
																								



4.
EXTRANEOUS SCATTERING AND ITS DISCRIMINATION IN GAS ELECTRON DIFFRACTION

Y. I. Tarasov, I. V. Kochikov, A. A. Ivanov, D. M. Kovtun, A. N. Rykov
Keywords: gas electron diffraction, additive and multiplicative noise, extraneous scattering, sector function
Pages: 427-432

Abstract >>
The division algorithm for additive and multiplicative noise components of the electron scattering intensity is proposed in the work. The procedure presented provides a substantial improvement in experimental data processing in comparison with the traditional method used by Russian research groups. A comparison of the additive noise with the simulated residual gas scattering shows that it is this scattering that is largely responsible for the strange contribution to the measured diffraction pattern.
																								



5.
DESIGN OF THE OPTIMAL SECTOR DEVICE AND DETERMINATION OF ITS PARAMETERS IN GAS ELECTRON DIFFRACTION

Y. I. Tarasov, I. V. Kochikov, A. A. Ivanov, D. M. Kovtun, G. A. Zhurko
Pages: 433-438

Abstract >>
This work presents a way to select the optimal form of the sector lobe and practical algorithms to determine the sector function of the device in use. Knowledge of the sector function enhances the quality of drawing a background line and ensures the division of multiplicative and additive noise components, thus increasing the reliability of structural parameters determined by gas electron diffraction.
Keywords: gas electron diffraction, sector function, background line.
																								



6.
FORMATION OF DISPERSE FERROMAGNETIC NANOPARTICLES IN ZEOLITES IN THE COURSE OF THERMAL ACTIVATION IN OXYGEN

. N. Martyanov, V. F. Yudanov
Pages: 439-444

Abstract >>
Samples of synthetic high-silica zeolites after high-temperature activation in oxygen are studied by ferromagnetic resonance. Observation of the fine structure of ferromagnetic resonance (FMR FS) indicates the formation of magnetic iron oxide nanoparticles in the course of thermal treatment of zeolites in oxygen. Features of the formation of a dispersed ferromagnetic phase in zeolites, geometric and magnetic characteristics of constituent nanoparticles are discussed.
Keywords: zeolites, thermal oxygen treatment, ferromagnetic nanoparticles, ferromagnetic resonance.
																								



7.
ELECTRON-PROTON EFFECT AND THE STRUCTURE OF EXCITED MOLECULAR COMPLEXES

K. K. Kalninsh
Keywords: charge transfer molecular complex, electron donor-acceptor bond, hydrogen bond
Pages: 445-464

Abstract >>
The essence of the electron-proton effect is clarified by the example of donor-acceptor complexes. It is shown that this effect plays a universal role in accelerating dark and photochemical processes due to interaction between electron and proton excitations.
																								



8.
SYNTHESIS AND CONFORMATIONAL ANALYSIS OF SOME CYANOMETHYLENE DERIVATIVES OF PIPERIDINES

A. Manimekalai, J. Anusuya, J. Jayabharathi
Keywords: molecular conformations, saturated heterocycles, six-membered heterocycles, computations, NMR spectra, mass spectra, A1, 3 strain
Pages: 465-475

Abstract >>
Five 4-dicyanomethylene derivatives 6-10, N-cyanoacetyl-cis-2,6-diphenylpiperidin-4-one 11 and 4-cyano(ethoxycarbonyl)-methylene-cis-2,6-bis(o-chlorophenyl)piperidine 12 were synthesised by condensing the appropriate piperidin-4-ones 13-17 with malononitrile/ethylcyanoacetate and their 1H and 13C NMR spectra were recorded. The 1H-1H COSY spectrum for 6 and NOESY spectra for 8, 10 and 11 were also recorded. Based on coupling constants and the results obtained from NOESY spectra boat conformation for 10 and epimerised chair conformations for 8 and 9 have been proposed. Other derivatives adopt normal chair conformations. Theoretical calculations and the 1H and 13C chemical shifts also support the above conformations. Mass spectra were also recorded for 6-12.
																								



9.
MOLECULAR DYNAMICS STUDY OF CRYSTALLINE WATER ICES

E. A. Zheligovskaya
Pages: 476-489

Abstract >>
The behavior of structures of H2O crystalline ices Ih, Ic, XI, VII, VIII, VI is studied in molecular dynamics experiment using the potential offered by Poltev and Malenkov. The behavior of the system consisting of one of the two identical interpenetrating, but without any common hydrogen bonds, water frameworks comprising the ice VI structure is also simulated. As a result of simulations, the ice VII structure has collapsed, whereas other systems proved to be stable. The reasons of instability of the ice VII and previously studied ice IV structures in molecular dynamics experiments are discussed. Based on the simulation results of the above-mentioned ices and previous simulation of ices II, III, IX, IV, and XII, the general regularities of dynamic properties of water molecules in crystalline water ices are formulated. Unreliability of results obtained by molecular dynamics in the investigation of self-organizing processes in aqueous systems is shown.
																								



10.
IR SPECTROSCOPY INVESTIGATION OF MOLECULAR ASSOCIATION IN THE ACETONE-TRICHLORMETHANE MIXTURE

M. T. Khatmullina, L. V. Rabchuk, V. V. Lazarev, A. S. Krauze
Keywords: acetone (AC), trichloromethane (TM), association, hydrogen bond, integral absorption coefficient (?), integral molar absorption coefficient
Pages: 490-494

Abstract >>
A significant increase in the stretching band intensity of trichloromethane in IR spectra of its solutions in acetone with increasing acetone mole fraction indicates the formation of hydrogen bonds between their molecules. The integral absorption coefficient (α) of this vibration is calculated. Experimental values of α are approximated by a theoretical dependence using the nonlinear least-squares method; association parameters are obtained. The relative volume fractions of H-bonded and free trichloromethane molecules are calculated depending on the total trichloromethane volume fraction in solution. The structure of the H-bonded associate is determined by quantum chemical calculations.
																								



11.
X-RAY DIFFRACTION ANALYSIS OF MICROREGIONS OF A CUMULATIVE COATING ON TITANIUM

A. V. Alekseev, S. A. Gromilov, I. B. Kireenko, T. N. Drebushchak, S. A. Kinelovskii
Keywords: titanium, titanium nitride, full-profile refinement, X-ray phase analysis, microhardness
Pages: 495-499

Abstract >>
Quantitative X-ray diffraction analysis of different parts of the coating on titanium obtained by cumulative explosion is performed. The examination of microregions of the coating sized from 1 mm to 0.1 mm reveals that the phase based on the cubic cell of titanium nitride dominates in the upper layers. The predominance of this phase in some regions of the coating provides their increased microhardness. Crystal chemical and EDX analyses indicate the development of non-stoichiometric phases of complex composition. The problem of site occupation factors of light atoms arising in the full-profile refinement of powder X-ray patterns is discussed.
																								



12.
ORIENTATIONAL DISORDER IN CRYSTAL STRUCTURES OF (NH4)3ZrF7 (NH4)3NbOF6

A. A. Udovenko, N. M. Laptash
Keywords: ammonium fluorozirconates and fluoroniobates, crystal structure, pentagonal bipyramid, orientational disorder
Pages: 500-506

Abstract >>
Crystal structures of (NH4)3ZrF7 (I) and (NH4)3NbOF6 (II) are refined by X-ray diffraction at room temperature. The compounds are isostructural and belong to the structural type of elpasolite: space group F23; a(I) = 9.4185(3) Å, (II) = 9.3371(5) Å; V(I) = 835.50(5) Å3, V(II) = 814.02(8) Å3; Z = 4; R(I) = 0.0145, and R(II) = 0.0138. The refinement of the structures in the space group Fm3m yields abnormally short X-X distances in the pentagonal bipyramid MX7 (X = F, O). The oxygen atom in II is identified by nb-X distances and occupies one of the axial vertices of the bipyramid. The Nb atom in II is statistically distributed over the position 24f, while Zr in I resides in the symmetry center. The pentagonal bipyramid MX7 has six independent orientations in I and twelve in II. One of three crystallographically independent ammonium groups of the structures is disordered over six or twelve equivalent orientations.
																								



13.
PHENOMENON OF TRANS-CIS ISOMERIZATION OF COPPER(II) B-DIKETONATE ON CO-CRYSTALLIZATION WITH LEAD(II) HEXAFLUOROACETYLACETONATE

I. A. Baidina, V. V. Krisyuk, E. V. Peresypkina, P. A. Stabnikov
Keywords: copper, lead, crystal chemistry of ?-diketonates, heterometallic complexes, cis-trans isomerism
Pages: 507-511

Abstract >>
X-ray diffraction structural study is carried out for crystals of a heterobimetallic complex derived from lead(II) hexafluoroacetylacetonate and copper(II) 2-methoxy-2,6,6-trimethylheptan-3,5-dionate prepared by co-crystallization of Pb(hfa)2 and trans-Cu(zis)2. In the novel compound Cu(zis)2⋅Pb(hfa)2 the copper complex is found to have cis-configuration. It is demonstrated that the main structural motif of this complex is coordination dimers Cu(zis)2⋅Pb(hfa)2 joint in polymeric chains of alternating molecules of the complexes. Crystal data for Cu(zis)2⋅Pb(hfa)2: a = 9.848(2) Å, b = 23.871(5) Å, c = 18.289(4) Å, β = 100.23(3), space group P21/n, Z = 4, dx = 1.701 g/cm3. The distance Pb-Cu in the dimer is 3.68 Å.
																								



14.
CRYSTAL STRUCTURE AND SPECTRAL CHARACTERISTICS OF {[(C6H5)NH]2C=NH(C6H5)}[B(C6H5)4]⋅ ⋅C2H5OH

T. M. Polyanskaya, E. A. Il'inchik, V. V. Volkov, M. K. Drozdova, O. P. Yur'eva, G. V. Romanenko
Keywords: triphenylguanidinium, tetraphenylborate, molecular and crystal structure, intermolecular interactions, IR spectra, luminescence
Pages: 512-521

Abstract >>
A novel compound of {[(C6H5)NH]2C=NH(C6H5)}[B(C6H5)4]⋅C2H5OH is prepared and examined by single crystal X-ray diffraction. Crystal data: C45H44BN3O, M = 653.64, monoclinic, space group P21/, unit cell parameters: a = 24.375(2) Å, b = 17.5829(15) Å, c = 18.090(1) Å, β = 105.277(2), V = 7479.0(11) Å3, Z = 8, dcalc = 1.161 g/cm3, T = 293 K, R1 = 0.064. The structure contains two crystallographically independent cations, two anions, and two solvate ethanol molecules. Three types of interactions occur between them: interionic N-H(N)π and N(H)πH(C), π-delocalized system of Ph rings of the anions, and interaction of ions with ethanol molecules N-HO-H(O)π. The compound is characterized by IR and luminescence spectra. At room temperature, the emission intensity grows with time of exposure to UV irradiation.
																								



15.
PREPARATION, MOLECULAR AND CRYSTAL STRUCTURES OF 3-(1-AMINO-2,2,2-TRIFLUOROETHYLIDENE)-1,1,4,5,6,7-HEXAFLUOROINDAN-2-ONE, 2-AMINO-1,1,4,5,6,7-HEXAFLUORO-3-TRIFLUOROACETYLINDENE, AND THEIR COMPLEXES WITH DIOXANE AND PYRIDINE

T. V. Rybalova, V. M. Karpov, Y. V. Gatilov, M. M. Shakirov
Keywords: perfluorinated enaminoketones, indan, indene, complexes, synthesis, structure, single crystal X-ray diffraction, quantum chemical calculations
Pages: 522-529

Abstract >>
3-(1-Amino-2,2,2-trifluoroethylidene)-1,1,4,5,6,7-hexafluoroindan-2-one (2) is synthesized by the interaction between 3-(1-amino-2,2,2-trifluoroethylidene)-2-imino-1,1,4,5,6,7-hexafluoroindan (1) and isopropylnitrite, and 2-amino-1,1,4,5,6,7-hexafluoro-3-trifluoroacetylindene (3) is prepared by hydrolysis. Single crystals are grown, and the molecular and crystal structure of enaminoketones obtained, the complex of compound 2 with 1,4-dioxane, and the complex of compound 3 with pyridine is studied. DFT calculations have been performed to find the complex formation energies of compounds 2 and 3 with dioxane and pyridine in the gas phase.
																								



16.
STRUCTURE OF NANOCRYSTALLINE PARTICLES OF METALLIC COBALT FORMED DURING THE REDUCTION OF CO3O4 OXIDE

S. V. Cherepanova, O. A. Bulavchenko, S. V. Tsybulya
Keywords: packing faults, simulation, in situ X-ray diffraction
Pages: 530-534

Abstract >>
X-ray diffraction is applied to investigate metallic cobalt obtained by the reduction of nanocrystalline particles of Co3O4. The particles of metallic cobalt have a high concentration of stacking faults, i.e., violations of the layer packing sequence ABABAB, which is seen in X-ray diffraction patterns as anisotropic broadening of diffraction peaks. Simulation of the diffraction patterns of α-Co with a different concentration of stacking faults is carried out.
																								



17.
INTERMOLECULAR INTERACTIONS AND THE STRUCTURE OF NEAR-SURFACE LAYERS IN HETEROGENEOUS TWO-COMPONENT SYSTEMS BASED ON NANOCYSTALLITES OF TITANIUM DIOXIDE

L. M. Babkov, T. V. Bezrodnaya, G. A. Puchkovskaya, K. E. Uspenskii, V. V. Shimanovaskaya
Keywords: heterogeneous system, titanium dioxide, nanocrystallite, benzophenone, 4-pentyl-4?-cyanobiphenyl, hydrogen bond, near-surface layer, structure, IR spectrum, molecular simulation
Pages: 535-540

Abstract >>
This contribution provides the theoretical background for the structure-determining role of hydrogen bonding in the formation of a near-surface layer of titania nanocrystallites, previously revealed by the authors in the investigation of IR experimental spectra of two-component solid mixtures of nanocrystalline titanium dioxide with benzophenone or 4-pentyl-4′-cyanobiphenyl. DFT calculations (B3LYP) in 6-31+G(d) basis set is used to simulate the structure and IR spectra of free molecules of water, 4-pentyl-4′-cyanobiphenyl, benzophenone and their -complexes formed in the near-surface layers of titania nanocrystallites due to presence of water adsorbed on their surfaces. Using the results of simulation and analysis of IR spectrum bands corresponding to stretching vibrations of polar bonds -H, =, ≡N, the formation mechanism of near-surface layers of titania nanocrystallites in the considered heterogeneous two-component systems is theoretically substantiated: they are formed by hydrogen-bonded complexes involving components of the mixture and water.
																								



18.
COMPUTER SIMULATION AND DIFFRACTION STUDIES OF THE STRUCTURE OF LIQUID BENZENE

P. M. Zorkii, L. V. Lanshina, T. V. Bogdan
Keywords: liquid benzene, structure, modeling, molecular dynamics, X-ray diffraction, neutron diffraction
Pages: 541-566

Abstract >>
The review offers critical analysis of the results of the diffraction studies and computer simulation of the structure of liquid benzene. It is shown that until recently, structural studies were mainly investigations of the nearest surroundings of molecules, but did not ultimately provide reliable data. Modern approaches to studies of liquids at higher levels are considered, and a structural model of liquid benzene is suggested.
																								



19.
COMPARATIVE ANALYSIS OF A FULL-ELECTRON BASIS SET AND PSEUDOPOTENTIAL FOR THE IODINE ATOM IN DFT QUANTUM-CHEMICAL CALCULATIONS OF IODINE-CONTAINING COMPOUNDS

A. G. Yurieva, . K. Poleshchuk, V. D. Filimonov
Keywords: quantum chemistry, DFT B3LYP/dgdzvp and B3LYP/6-311G(d) quantum-chemical methods
Pages: 567-571

Abstract >>
A systematic study was performed to examine the possibilities of the B3LYP DFT method in a dgdzvp full-electron basis and of the method including a pseudopotential for iodine compounds. The full-electron basis generally gives better agreement for X-I bond lengths and reaction enthalpies of iodination of organic compounds and equally good agreement in calculations of the IR vibrations of the X-I bond length compared with the studies using the pseudopotential. The full-electron basis also allows adequate calculations of the quadrupole coupling constants of iodine atoms and is generally characterized by smaller computing times.
																								



20.
NANOSIZED THERMOMETRIC NMR SENSORS BASED ON THE PARAMAGNETIC COMPLEX ION PAIRS OF LANTHANIDES(III) FOR TEMPERATURE DETERMINATIONS IN LOW-POLAR NONAQUEOUS SOLUTIONS

S. P. Babailov
Keywords: lanthanide-induced shifts, temperature dependence of LIS, molar paramagnetic susceptibility, lanthanides, NMR, magnetic resonance tomography, nonaqueous solutions, thermometric NMR sensors, ion pairs
Pages: 572-574

Abstract >>
For temperature determination in solutions it is suggested that the temperature dependence of the paramagnetic lanthanide-induced shifts (LIS) in the NMR spectra on the ligand nuclei be used for [Ln(PTA)2(18-crown-6)]+[Ln(PTA)4]- complex ion pairs formed in CCl4, CDCl3, CD2Cl2, CD3C6D5, and C2D3N type low-polar solvents (Ln = La, Ce, Pr, Nd, Eu; PTA is the pivalyltrifluoroacetonato anion). It was found experimentally that the [Ln(PTA)2(18-crown-6)]+ complex cation molecules (Ln = Ce and Pr) proved most suitable for use as nanosized (≈1.1 nm) probes for temperature determinations in nonaqueous solutions. A linear dependence of the LIS on the 1H nuclei of different groups and the difference between the LIS corresponding to the CH2 groups of the 18-crown-6 molecules and the CH groups of the PTA anions on the reciprocal temperature (1/T) was found. The LIS of the individual signals of different groups in Ln paramagnetic complexes (relative to the signals of the diamagnetic analogs, e.g., La or Lu) may be used for temperature control in the sample, although the temperature measurement error is smaller (≤ 0.04 K) when the difference between the LIS of the CH2 and CH groups is used. Due to the high thermodynamic and kinetic stability combined with small sizes of [Ln(PTA)2(18-crown-6)]+[Ln(PTA)4]- molecules in nonaqueous solutions, these compounds may be used as thermometric NMR sensors directly in reaction media for in situ control over temperature.
																								



21.
CRYSTAL STRUCTURE OF COPPER(II) trans-BIS-(4-PHENYLIMINoPENTAN-2-ONATE)

V. E. Bryndin, A. I. Smolentsev, P. A. Stabnikov, I. K. Igumenov
Keywords: crystal structure, phenylketoiminate, copper(II), crystal chemistry
Pages: 575-578

Abstract >>
trans-Bis-(4-phenyliminopentan-2-onato)Cu(II) (5), which is a phenyl-substituted ketoimine, was synthesized, and an X-ray study was performed for this compound. Crystal data for CuN2O2C22H24: a = 11.4557(3) Å, b = 26.6845(9) Å, c = 14.2976(5) Å, β = 113.2270(10); space group P21/n, Z = 8, dcalc = 1.363 g/cm3, R = 0.033. The structure is molecular and built of isolated trans complexes. The central copper atom is surrounded by four atoms (2+2N) with the average distances Cu-O 1.904(3) Å and Cu-N 1.962(3) Å. The polyhedron around the copper atom is a distorted tetrahedron; the average values of the O-u-O and N-Cu-N trans bond angles are 147(2) and 150(2), respectively. The average value of the O-Cu-N angles is 94(1).
																								



22.
CRYSTAL STRUCTURE OF [(C6H5)4P][Ni(B9C2H11)2]⋅CCl4

T. M. Polyanskaya, M. K. Drozdova, V. V. Volkov
Keywords: metal derivative of ortho-carborane(12), nickel(III) bisdicarbollyl anion, tetraphenyl- phosphonium, synthesis, molecular and crystal structure
Pages: 579-584

Abstract >>
A new compound containing the tetraphenylphosphonium cation and the nickel(III) bisdicarbollyl anion, [(C6H5)4P][Ni(B9C2H11)2]⋅CCl4, was synthesized and investigated by XRD at room temperature (295 K). Crystal data: C29H42B18PCl4Ni, M = 816.69, monoclinic, space group P2/; unit cell parameters a =
13.5873(6) Å, b = 7.1475(2) Å, c = 20.7829(8) Å, β = 94.4595(13), V = 2012.2(2) Å3, Z = 2, dcalc = 1.348 g/cm3. The structure was solved by direct and Fourier methods and refined by the full-matrix least squares method in an anisotropic (isotropic for H) approximation to the final R1 = 0.0466 for 3055 Ihkl ≥ 2σI of 23,655 reflections collected and 5618 independent Ihkl (Bruker X8 APEX diffractometer, λMoKα).
																								



23.
CRYSTAL STRUCTURE OF AMMONIUM PENTACHLORO-AQUARUTHENATE(III) (NH4)2[Ru(H2O)Cl5]

V. A. Emel'yanov, A. V. Virovets, I. A. Baidina
Keywords: ruthenium, chloro complexes, X-ray analysis, crystal chemistry
Pages: 585-588

Abstract >>
The structure of ammonium pentachloroaquaruthenate was established by X-ray diffraction analysis. The structure was built of the [Ru(H2O)Cl5]2- complex anions and cations. The compound was obtained in the form of dark red fine crystals, which are stable on storage in air.
																								



24.
NOVEL COPPER(II) COMPLEX WITH UNUSUAL P-STACKING STRUCTURE, [CuII(SSC)Cl]2⋅CH3OH⋅2H2O (SSC = SALICYLALDEHYDE SEMICARBAZONE ANION)

J.-L. Wang, B. Liu, B.-S. Yang, S.-P. Huang
Keywords: HSSC, copper(II), complex, crystal structure, π-π interactions, weak interactions
Pages: 589-593

Abstract >>
The crystal structure of [CuII(SSC)Cl]2⋅CH3OH⋅2H2O (SSC = salicylaldehyde semicarbazone anion) was determined by single crystal X-ray diffraction method at 293 K. Crystal data for Cu2C17H24Cl2N6O7: a = 10.272(2), b = 10.297(2), c = 11.462(2) A, α = 82.860(3), β = 78.384(3), γ = 81.330(2), triclinic, space group , Z = 2, dcalc = 1.769 g/cm3, R1
= 0.038. One N and two O atoms of SSC- occupy three coordination sites around Cu(II). The fourth site is occupied by Cl- to yield distorted square-planar environment. Two molecules of the complex form a planar dimer through intermolecular N-H...KO hydrogen bonds. The most striking feature of the crystal structure is the packing of the planar dimers within the crystal. The interplanar distances between adjacent two layers are 3.280 A, indicative of strong π-π non-covalent interactions. Molecules of solvent methanol and water are included in the crystal as additional components.
																								



25.
CRYSTAL STRUCTURE OF BARIUM BIS[N-(2-HYDROXYETHYL)IMINODIACETATO]COBALTATE(III) HYDROCARBONATE DIHYDRATE BA(M4-HCO3)[(N)-CO(HEIDA)2]⋅2H2O

M. Zabel, A. L. Poznyak, V. I. Pavlovskii
Keywords: crystal structure, cobalt(III) complex, barium hydrocarbonate, N-(2-hydroxyethyl)imino- diacetate ion.
Pages: 594-597

Abstract >>
Ba[Co(heida)2](HCO3)⋅2H2O crystals were grown (orthorhombic, a = 9.4491(5) Å, b = 10.9719(5) Å, c = 19.6077(9) Å, Z = 4, space group Pca21), and their structure was solved by X-ray diffraction. The Co atoms in the complex anion were coordinated by two N-(2-hydroxyethyl)iminodiacetate (heida) ligands via the N atom and two O atoms of each ligand. The Ba atoms and the complex anions form "honeycomb" layers linked via three atoms. The "honeycombs" are additionally linked by their atoms with the atoms of the hydroxyethyl groups. The Ba atoms are aligned within a layer and linked via the bridging HCO3 hydrocarbonate groups. The c.n. of atoms is 10 (one water molecule; five atoms of the complex anions, one from each of the nearest neighbors; and four atoms of the hydrocarbonate ions).