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Journal of Structural Chemistry

2012 year, number 1

1.
A Quantum chemical study of the structure of O=NO-ON=O peroxide and the reaction mechanism of NO oxidation in the gas phase

I. I. Zakharov, B. F. Minaev
Keywords: quantum chemical calculations, N2O4 nitrogen peroxide, NO oxidation reaction, NO2 dioxide
Pages: 7-17

Abstract >>
A DFT/B3LYP method using the 6-311++G(3df) basis set is employed to calculate the geometric, electronic, and thermodynamic parameters of O=NO-ON=O peroxide as an isomer of N2O4 dinitrogen tetraoxide. Calculations of the configuration interaction in a system of three paramagnetic particles with open shells have shown for the first time that the formation of cis-cis peroxide in the oxidation reaction of nitrogen oxide 2NO (2∏) + O2 (3g) → O=NO-ON=O (1A) proceeds without an energy barrier in accordance with recently performed studies. The molecular orbital scheme of the barrierless activation of molecular oxygen and the driving force of the NO oxidation reaction are considered. A spontaneous character of the process is based on the idea of spin-catalysis when the reaction proceeds in the two-triplet state with total zero spin. The obtained results are in agreement with the experimental data on a spontaneous and irreversible process characterized by the observed negative activation energy.
																								



2.
A QUANTUM CHEMICAL STUDY OF PHOTOCHEMICAL PROCESSES IN THE REACTION Se + O2 → SeO2 WITH ALLOWANCE FOR THE SPIN ORBIT INTERACTION

G. I. Kobzev, D. G. Urvaev, K. S. Davydov, Y. V. Zaika
Keywords: potential energy surface cross-section, excited selenium oxocomplexes, singlet oxygen, spin-orbit interaction, zero field splitting parameters
Pages: 18-33

Abstract >>
DFT, SA-MCSCF, and MRMP/MCQDPT2 methods in the 6-311++G(2d) basis set are employed to consider the features of the formation reaction of key intermediates (SeOO, Se(O2)) and photochemical dissociation of selenium dioxide with the formation of singlet oxygen. The cross-sections of potential energy surfaces of SeO2, Se(O2), and SeOO are constructed and the terms of their ground and excited states are analyzed at the SeOO dissociation limit with regard to spin-orbital interaction. Possible formation channels of 12 (1Δg, reactive oxygen species during the decay of the excited states of selenium oxocomplexes are revealed. The effect of the spin-orbit interaction on the character of electronic spectrum transitions and zero field splitting in oxygen is estimated.
																								



3.
AB INITIO STUDY OF SCANDIUM FLUORIDE MOLECULES: ScF, ScF2, AND ScF3

V. G. Solomonik, A. A. Mukhanov
Keywords: scandium fluorides, molecular structure and spectra, atomization enthalpy, quantum chemistry, coupled-cluster method, extrapolation to the limit of the complete basis set
Pages: 34-40

Abstract >>
Equilibrium geometric parameters, normal mode frequencies and intensities in IR spectra, atomization enthalpy, and relative energies of low-lying electronic states of scandium fluoride molecules (ScF, ScF2, and ScF3) are calculated by the coupled-cluster method (CCSD(T)) in triple-, quadruple, and quintuple-zeta basis sets with the subsequent extrapolation of the calculation results to the complete basis set limit. The ScF molecule is also studied by the CCSDT technique. The error in the approximate calculation of triple excitations in the CCSD(T) method does not exceed 0.002 Å for the equilibrium internuclear distance Re, 4 cm-1 for the vibrational frequency, and 0.2 kcal/mol for the dissociation energy of the molecule. In the ground electronic state 2A1(C2v) of ScF2 molecules, Re(Sc-F) = 1.827 Å and αe(F-Sc-F) = 124.2; the energy barrier to bending (linearization) h = Emin(Dh) - Emin(C2v) = 1652 cm-1. The relative energies of 2Δg and 2Πg electronic states are 3522 cm-1 and 14633 cm-1 respectively. The bond distance in the ScF3 molecule (, D3h) is refined: Re(Sc-F) = 1.842 Å. The atomization enthalpies Δat of ScFk molecules are 139.9 kcal/mol, 289.0 kcal/mol, and 444.8 kcal/mol for k = 1, 2, 3 respectively.
																								



4.
Role of sublattices in the formation of the electronic structure and chemical bonding in a Zn2SiO4 crystal with a defect chalcopyrite lattice

Y. M. Basalaev, S. A. Marinova
Keywords: density functional, sublattice method, chalcopyrite
Pages: 41-44

Abstract >>
The effect of sublattices on the electronic structure of Zn2SiO4 crystals is ab initio studied from the first principles calculations at the density functional theory level. Based on the analysis of band spectra and sublattices the different role of Zn and Si cations in the formation of the valence band structure is determined, which is due to the crystal structure and atomic interactions in SiO4 and ZnO4 cationic tetrahedra.
																								



5.
CALCULATED PROPERTIES OF NEUTRAL AND CHARGED AlnCOm CLUSTERS BY DENSITY FUNCTIONAL THEORYG.

G. Ma, L. Guo
Keywords: AlnCom clusters, density functional theory, frequency analysis, structural properties
Pages: 43-53

Abstract >>
Density functional calculations are performed to study the structures and electronic properties of AlnCom clusters with n = 1-7 and m = 1, 2. Frequency analysis is also performed after structural optimization to make sure that the calculated ground states are real minima. The corresponding total and binding energies, adiabatic electron affinities and ionization potentials are presented and discussed to aid the identification of our calculations. The BSSE correction is also considered in our calculation. Among AlnCom, AlnCo, and AlnCo clusters (n = 1-7 and m = 1-2), Al4Co-, Al6Co-, Al2Co2, and Al6Co2 are predicted to be more stable. Our results are consistent with the available experimental data.
																								



6.
Structure and Thermodynamics of Phosphorus Oxide Caged Clusters

R.A. Laviolette, M.T. Benson
Keywords: density functional theory, phosphorus oxide clusters, LDA, GGA
Pages: 54-59

Abstract >>
The structure and thermodynamics of the following phosphorus oxide caged clusters were calculated in the gas phase at STP via both the local density approximation (LDA) and a generalized gradient approximation (BLYP) of density functional theory: the experimentally characterized trioxide (P4O6) and pentoxide (P4O10), and in order of thermodynamic preference, the hypothetical P24O60, P8O20, P24O48, and P20O20. All of the hypothetical oxides would dissociate to the pentoxide at equilibrium. Secondarily, the LDA calculation of the enthalpy of formation was unexpectedly superior to the BLYP calculation.
																								



7.
HYDROGEN BONDING, IR SPECTRUM, AND THE STRUCTURE OF METHYL-β-D-GLUCOPYRANOSIDE

L. M. Babkov, M. V. Korolevich, E. A. Moiseikina
Keywords: methyl-?-D-glucopyranoside, hydrogen bonding, -complex, molecular simulation, quantum chemistry, density functional, normal vibrations, IR spectrum, frequency, intensity
Pages: 60-67

Abstract >>
A theoretical study of the structure and vibrational spectrum of methyl-β-D-glucopyranoside is performed with allowance for the hydrogen bond effect on them. At the density functional theory level with the use of the B3LYP functional in the 6-31G(d) basis set the structural dynamic models of a free molecule of methyl-β-D-glucopyranoside and its simplest complexes with hydrogen bonding in the form of dimers with different structures are constructed. Energies are minimized; structures, electro optical parameters, force constants, and normal vibrational frequencies in the harmonic approximation and their intensities in IR spectra are calculated; the hydrogen bond energy is estimated. Based on the calculation, the conclusions are drawn about the structure of the methyl-β-D-glucopyranoside sample, the formation and interpretation of its IR spectrum, and the possibilities of the used density functional theory method.
																								



8.
MOLECULAR AND CRYSTAL STRUCTURE, SPECTROSCOPIC PROPERTIES OF 2-METHYL-4-(3-METHYL-3-PHENYL-CYCLOBUTYL)-THIAZOLE DETERMINED BY THE EXPERIMENTAL METHOD AND A QUANTUM CHEMICAL CALCULATION

Ç. Yüksektepe, N. ??ali??kan, I. Yilmaz, A. ??ukurovali
Keywords: ab initio calculation, semi-empirical method, B3LYP, conformational analysis, vibrational assignment, X-ray structure determination
Pages: 68-77

Abstract >>
The structure of the synthesized title compound is characterized by IR, UV-Visible spectroscopy, and single-crystal X-ray diffraction (XRD). The new compound (C18H23NS) crystalizes in the monoclinic P21/c space group. In addition to the crystal structure from the X-ray experiment, the molecular geometry, vibrational frequencies, atomic charge distribution, and frontier molecular orbital (FMO) analysis of the title compound in the ground state are calculated by density functional teory (B3LYP) with 6-311G(d,p) and 6-31G(d,p) basis sets. The results of the optimized molecular structure are presented and compared with the experimental values. The computed vibrational frequencies are used to determine the types of molecular motions associated with each of the observed experimental bands. To determine the conformational flexibility, the molecular energy profile of (1) is obtained by semi-empirical (AM1) and (PM3) calculations with respect to a selected degree of torsional freedom. Moreover, molecular electrostatic potential (MEP) and thermodynamic parameters of the title compound were calculated by the theoretical methods.
																								



9.
CRYSTAL STRUCTURE AND LUMINESCENCE OF 2,2-DIFLUORO-4,6-(4-METHYLPHENYL)-1,3,2-DIOXABORINE

B. V. Bukvetskii, E. V. Fedorenko, A. G. Mirochnik, A. Y. Beloliptsev
Keywords: boron difluoride ?-diketonate, 2, 2-difluoro-4, 6-(4-methylphenyl)-1, 3, 2-dioxaborine, crystal structure, luminescence, H and J aggregates, quantum chemical simulation
Pages: 78-86

Abstract >>
The crystal structure, luminescence properties of 2,2-difluoro-4,6-(4-methylphenyl)-1,3,2-dioxaborine (H3C6H4COCHCOC6H4CH3BF2) crystals and solutions at different concentrations are examined at T 296 K and 156 K.
																								



10.
ELECTROSTATIC INTERACTIONS IN MICELLAR SOLUTIONS OF SODIUM n-ALKYL SULFATES AND APPLICABILITY OF THE POISSON-BOLTZMANN EQUATION FOR THEIR CALCULATION

V. S. Kuznetsov, N. V. Usol'tseva, V. V. Bykova
Keywords: ionic micelles, electrostatic interactions, Poisson-Boltzmann equation, Gibbs energy of micellization, chemical potential, Debye-Hueckel theory
Pages: 87-97

Abstract >>
By the example of four even members in a homologous series of sodium n-alkyl sulfates (decyl-, dodecyl-, tetradecyl-, and hexadecyl sulfate) and with the use of the Debye-Hueckel theory of strong electrolytes the parameters are calculated that determine electrostatic interactions in micellar solutions of surfactants. Calculation results for the Gibbs electrostatic energy of micellization are compared to those obtained from one of the approximate solutions of the Poisson-Boltzmann equation and also to the results of its numerical integration for spherical micelles. Applicability conditions of the Debye-Hueckel theory are determined with respect to the micelle concentration and size and the number of carbon atoms in a surfactant molecule. It is shown that the Debye-Hueckel theory in the proposed version enables an efficient and quite accurate calculation of all electrostatic properties of micelles and ionic micellar solutions for surfactants with a number of carbon atoms in a molecule starting from 10 and more and at concentrations up to 0.15 mol/dm3.
																								



11.
Molecular dynamics simulation OF liquid mixtures of benzene with chlorobenzene

T. V. Bogdan, E. S. Alekseev
Keywords: molecular dynamics simulation, radial angular distribution function, liquid benzene, liquid chlorobenzene, liquid benzene-chlorobenzene mixtures, chlorine aggregation
Pages: 98-104

Abstract >>
A molecular dynamics method is used to simulate liquid mixtures of benzene and chlorobenzene at different concentrations. Radial angular distribution functions (RADFs) for distances between the benzene ring planes and the angle between them were calculated to analyze the structure of pure components and mixtures. In chlorobenzene, the highest RADF maximum at a distance between the mass centers of the benzene rings of about 4 Å corresponds to the stacked configurations of molecules, and at 5-7 Å the number of stacked contacts are much less than that at 4 Å and is comparable with the orthogonal ones.
In liquid benzene, the number of stacked and orthogonal configurations is approximately equal in a range from 4 Å to 7 Å. RADF for benzene reveals extended regions of correlation, which gives evidence of the occurrence of agglomerates bound by specific interactions between the benzene rings. These agglomerates are not characteristic of chlorobenzene, but the presence of maxima on the radial distribution function for the distances between chlorine atoms indicates chlorine aggregation. The effect of halogen aggregation on the structure of benzene-chlorobenzene mixtures is considered. The obtained results are compared with the data on molecular light scattering.
																								



12.
ANALYSIS OF PAIR HETEROVALENT SUBSTITUTIONS IN SCHEELITE-TYPE MOLYBDATES AND TUNGSTATES

V. D. Zhuravlev, O. G. Reznitskikh
Keywords: scheelite, molybdates, tungstates, heterovalent substitutions
Pages: 105-109

Abstract >>
An analysis of the formation of solid solutions in MAO4-(Me0.5Ln0.5)AO4 systems, where Me = Li, Na, K; M = Ca, Sr, Ba, Pb, Cd; Ln = La-Gd, Y, Bi; A = Mo, W, is performed in the approximation of regular solutions. Equations that make it possible to determine the temperature of the transition of limited solid solutions to unlimited ones at heterovalent substitutions M2+ ↔are obtained.
																								



13.
CRYSTAL STRUCTURES OF TETRAFLUOROANTIMONATES(III) OF SINGLE AND DOUBLE PROTONATED 3-AMINO-1,2,4-TRIAZOLIUM CATIONS

A. A. Udovenko, N. V. Makarenko, R. L. Davidovich, L. A. Zemnukhova, E. V. Kovaleva
Keywords: X-ray crystallography, crystal structure, tetrafluoroantimonate(III), 3-amino-1, 2, 4-triazolium, hydrogen bond
Pages: 110-116

Abstract >>
Crystal structures are determined by X-ray crystallography for tetrafluoroantimonates(III) of single and double protonated 3-amino-1,2,4-triazolium cations of the composition (C2H5N4)SbF4 (I) (monoclinic: a = 4.7723(6) Å, b = 19.643(2) Å, c = 7.6974(9) Å, β = 97.239(2), Z = 4, Cc space group) and (C2H6N4)(SbF4)2 (II) (monoclinic: a = 4.7617(3) Å, b = 15.512(1) Å, c = 7.4365(5) Å, β = 107.706(1), Z = 2, P21/n space group). The structure of I is built from complex [SbF4] anions and single charged (C2H5N4)+ cations; the structure of II is built from the same anion and double charged 3-amino-1,2,4-triazolium cation: (C2H6N4)2+. In the structure, weak interactions Sb⋯F join the anions in polymeric layers [SbF4] that are assembled in a 3D framework by N-H⋯F hydrogen bonds. The formation of the double protonated 3-amino-1,2,4-triazolium cation (C2H6N4)2+, found in the crystal structure of II, is observed for the first time.
																								



14.
synthesis and structure investigation of Co(III) complex salts with the perrhenate anion

I. A. Baidina, E. Y. Filatov, E. V. Makotchenko, A. I. Smolentsev
Keywords: cobalt, ammonia, ethylenediamine, perrhenate ion, powder X-ray diffraction analysis, single crystal X-ray diffraction analysis, crystal chemistry
Pages: 117-123

Abstract >>
Complex salts of the composition [Co(NH3)6](ReO4)32H2O (I), [Co(en)3](ReO4)3 (II), [Co(NH3)5H2O](ReO4)32H2O (III), and [Co(NH3)5Cl](ReO4)20.5H2O (IV) are obtained. Their crystal structures are determined by single crystal XRD. Crystallographic characteristics: (I) a = 9.9797(3) Å, b = 12.6994(3) Å, c = 14.7415(4) Å, β = 102.870(1), C2/c space group; (II) a = 8.0615(3) Å, b = 8.4483(4) Å, c = 8.8267(4) Å, α = 61.923(2), β = 89.552(2), γ = 72.295(2), P1 space group; (III) a = 8.0086(4) Å, b = 12.9839(6) Å, c = 17.5122(7) Å, β=91.858(1), P21/n space group; (IV) a = 14.9446(3) Å, b = 14.6562(4) Å, c = 12.2434(4) Å, Cmc21 space group.
																								



15.
ARCHITECTURE OF FRAMEWORK COPPER(I) HALIDE π-COMPLEXES WITH N-ALLYL-N,N,N′,N′-TETRAMETHYLETHYLENEDIAMINIUM AND N,N′-DIALLYL-N,N,N′,N′-TETRAMETHYLETHYLENEDIAMINIUM: SYNTHESIS AND CRYSTAL STRUCTURE OF [{C2H4N2(H+)× (CH3)4(C3H5)} Cu4Cl6] AND [{C2H4N2(CH3)4(C3H5)2}0.5Cu2Cl1.67Br1.33]

M. M. Monchak, E. A. Goreshnik, M. G. Mys'kiv
Keywords: copper(I), allyl derivatives of N, N, N?, N?-tetramethylethylenediamine, π-complexes, copper halide fragments, crystal structure
Pages: 124-129

Abstract >>
N,N,N′,N′-tetramethylethylenediamine is obtained by the reaction of ethylenediamine with formaldehyde and formic acid (the Eschweiler-Clarke reaction) and then alkylated with allyl chloride (or bromide) in a ratio of 1:1 or 1:2 to obtain N-allyl-N,N,N′,N′-tetramethylethylenediaminium and N,N′-diallyl-N,N,N′,N′-tetramethylethylenediaminium bromide respectively. [{C2H4N2(H+)(CH3)4(C3H5)}Cu4Cl6] (1) and [{C2H4N2(CH3)4(C3H5)2}0.5Cu2Cl1.67Br1.33] (2) π-complexes are obtained from alcohol solutions containing an ethylenediamine derivative and copper(II) chloride by ac-electrochemical synthesis on copper wire electrodes. An XRD study of the complexes is carried out. The crystals are monoclinic; 1: P21/n space group, a = 9.0081(6) Å, b = 12.5608(7) Å, c = 16.8610(10) Å, β = 102.061(3), V = 1865.7(2) Å3, Z = 4; 2: 2/ space group, a = 14.462(2) Å, b = 12.519(1) Å, c = 12.762(2) Å, β = 107.861(5), V = 2199.1(4) Å3, Z = 8. The structure of 1 consists of infinite copper halide networks with four crystallographically independent copper atoms, one of which coordinates the double bond of the allyl group of the ligand. The [C2H4N2(H)(CH3)4(C3H5)]2+ cations are attached above and below the plane of the network. The individual fragments are bonded via an extensive system of (N)HCl and (C)HCl hydrogen bonds. The structure of 2 contains a three-dimensional copper halide framework whose cavities contain the [C2H4N2(CH3)4(C3H5)2]2+ cations that are π-coordinated with copper(I) atoms. In both structures, the Cu(I) atom that coordinates the = bond has a trigonal-pyramidal coordination environment consisting of the double = bond of the corresponding ligand and three halogen atoms. The other Cu(I) atoms have a tetrahedral environment consisting solely of halogen atoms. The Cu-(C=C) distance is 1.958(1) Å (1) and 1.974(1) Å (2).
																								



16.
CRYSTAL STRUCTURES OF RHODIUM(III) AQUA ION WITH TETRAHEDRAL ANIONS

S. N. Vorob'eva, I. A. Baidina, A. V. Belyaev, N. I. Alferova
Keywords: rhodium, aqua ion, coordination compounds, crystal structure
Pages: 130-136

Abstract >>
The crystal structures of compounds of the composition [Rh(H2O)6]2(SO4)35H2O (I) and [Rh(H2O)6]PO4 (II) are determined. Crystallographic data for I: a = 7.272(9) Å, b = 27.047(1) Å, c = 12.464(9) Å, β = 97.038(10), P21 space group, Z = 4, dx = 2.184 g/cm3; for II: a = 9.746(6) Å, b = 6.877(7) Å, c = 23.623(6) Å, β = 100.601(10), C2/c space group, Z = 8, dx = 2.611 g/cm3. Compounds are analyzed by IR spectroscopy and powder XRD. Crystalline phase I is well soluble in water, whereas II is almost insoluble.
																								



17.
CRYSTAL STRUCTURES OF TRANS-[Re6S8(CN)2L4] COMPLEXES, L = PYRIDINE OR 4-METHYLPYRIDINE

A. Y. Ledneva, N. G. Naumov, A. V. Virovets, S. Cordier, Y. Molard
Keywords: rhenium, octahedral cluster, crystal structure, stacking interactions, topological packing analysis
Pages: 137-141

Abstract >>
The structures of three novel octahedral rhenium cluster compounds [Re6S8(CN)2(py)4]H2O (1), [Re6S8(CN)2(4-Mepy)4] (2), [Re6S8(CN)2(4-Mepy)4]4-Mepy (3) (py = pyridine, 4-Mepy = 4-methylpyridine) are determined by X-ray crystallography. Crystal data are: C2/m space group, a = 14.813(1) Å, b = 14.772(1) Å, = 9.2122(6) Å, β = 119.085(2), V = 1761.7(2) Å3, dx = 3.318 g/cm3, R = 0.0585 (1); I41/amd space group, a = 16.0018(3) Å, c = 14.7186(5) Å, V = 3768.81(16) Å3, dx = 3.169 g/cm3, R = 0.0489 (2); P21/c space group, a = 9.0452(4) Å, b = 15.8065(7) Å, c = 15.2951(6) Å, β = 103.700(2), V = 2124.57(16) Å3, dx = 2.957 g/cm3, R = 0.0245 (3). Molecular cluster complexes interact via π-π stacking affording 3D frameworks in 1 and 2 and chains in 3.
																								



18.
CRYSTAL STRUCTURE OF [CuL](NO3)(ReO4) AND [CuL](ReO4)2 (L = 4,6,6-TRIMETHYL-1,9-DIAMIN-3,7-DIAZANON-3-EN)

E. A. Bykova, S. P. Khranenko, E. Y. Semitut, S. A. Gromilov
Keywords: copper, rhenium, crystal chemistry, single crystal X-ray diffraction, thermal studies
Pages: 142-149

Abstract >>
The crystal structures of [CuL](NO3)(ReO4) and [CuL](ReO4)2 (L is 4,6,6-trimethyl-1,9-diamino-3,7-diazanon-3-en) are studied. The square coordination of the copper atom in [CuL](NO3)(ReO4) is completed to a distorted octahedron by two oxygen atoms: CuO 2.393 Å and CuO 2.685 Å, and that in [CuL](ReO4)2, by CuO 2.468 Å and 2.697 Å. The products of thermolysis of the salts in a hydrogen atmosphere at 800C are mixtures of nanocrystalline metal powders with coherent scattering regions of ~45 nm.
																								



19.
A SINGLE CRYSTAL X-RAY STUDY OF THE PRODUCTS OF HALOGEN MERCURY CYCLIZATION OF 8-ALLYLTHIOQUINOLINE

P. A. Slepukhin, V. I. Batalov, D. G. Kim, V. N. Charushin
Keywords: 8-allylthioquinoline, mercury halides, halogen mercury cyclization, organomercury compounds, salts of 3-(halogen-mercurimethyl)-2, 3-dihydro[1, 4]thiazino[2, 3, 4-ij]quinolinium
Pages: 149-154

Abstract >>
The reaction products of 8-allylthioquinoline with mercury halides are studied by single crystal X-ray diffraction. It is shown that the products are organomercury derivatives of salts of 2,3-dihydro[1,4]-thiazino[2,3,4-ij]quinoliniuim
																								



20.
CRYSTAL STRUCTURES OF [Hg(N-ETHYLTHIOUREA)2(CN)2] AND [Hg(N-PROPYLTHIOUREA)2(CN)2]

H. Sadaf, S. Ahmad, S. Sharif, I.U. Khan, M. Akkurt, S.W. Ng, M.I. Khan, S.A. Bashir, M. Mufakkar
Keywords: mercury(II) cyanide, N-ethylthiourea, N-propylthiourea, X-ray structures
Pages: 155-159

Abstract >>
Two mercury(II) cyanide complexes of N-ethylthiourea (Ettu) and N-propylthiourea (Prtu) ligands, [Hg(Ettu)2(CN)2] (1) and [Hg(Prtu)2(CN)2] (2), were prepared and their crystal structures were determined by X-ray crystallography. In both structures, the mercury atom is coordinated to two sulfur atoms of thioureas and two cyanide carbon atoms in a pseudo-tetrahedral mode with the bond angles in the range of 90.52(11)-162.2(3). The structures are stabilized by N-H---S, N-H---N, and C-H---N intramolecular and intermolecular hydrogen bonds.
																								



21.
INFLUENCE OF HYDROGEN BONDS ON THE MOLECULAR STRUCTURE AND CONFORMATIONS OF TWO (C30H48O2) PENTACYCLIC TRITERPENE ISOMERS

R.S. Corr??a, S.R. Souza e silva, L.P. Duarte, G.D.F. Silva, L.C.A. Barbosa, J. Ellena, A.C. Doriguetto
Keywords: Maytenus imbricata, pentacyclic triterpene, crystal structure, molecular conformation, static disorder, hydrogen bond
Pages: 160-166

Abstract >>
The structural study of two (C30H48O2) pentacyclic triterpene (PCTT) isomers is presented. These terpenes, known as 30-hydroxy-lup-20(29)-en-3-one (1) and (11α)-11-hydroxy-lup-20(29)-en-3-one (2), were isolated from Maytenus imbricata Mart. Ex Reissek (Celastraceae). The molecular structure of 1 and 2 differs in the position of the hydroxyl group. Both compounds crystallize in non-centrosymmetric space groups with two molecules in the asymmetric unit. The crystal structure of 1 shows a triclinic P1 space group (a = 9.5518(1) Å, b = 9.7083(1) Å, c = 14.4696(2) Å, α = 93.832(1), β = 102.833(1) and γ = 103.307(1)), while compound 2 crystallizes in a monoclinic P21 one (a = 13.4439(16) Å, b = 14.4463(14) Å, c = 13.5224(9) Å and β = 99.703(8)). The two molecules independent by symmetry of 1 differ slightly due to the presence of static disorder in oxygen atoms. In addition, the intermolecular geometries of 1 and 2 were analysed, and in each isomer the crystal packing is stabilized by O-H⋯O intermolecular hydrogen bonds and van der Waals forces.
																								



22.
FEATURES OF THE BEHAVIOR OF 5-SUBSTITUTED N(3)-ACYL-4,6-DIARYL-3,4-DIHYDROPYRIMIDIN-2(1)-ONES UNDER ELECTRON IONIZATION

V. F. Sedova, L. M. Pokrovskii, O. P. Shkurko
Keywords: mass spectra, dissociative ionization, elimination, 3, 4-dihydropyrimidin-2-ones, N(3)-acyl-3, 4-dihydropyrimidin-2-ones
Pages: 167-175

Abstract >>
Mass spectra of 5-substituted N(3)-acyl-4,6-diaryl-3,4-dihydropyrimidin-2(1H)-ones are studied. The features of the dissociative ionization of their molecular ions, which occurs with ketene elimination from the acyl group, are revealed. The subsequent fragmentation of fragment ions proceeds according to the rules established for pyrimidin-2(1H)-one derivatives.
																								



23.
HYDRATION NUMBERS OF α-ALANINE IN AN AQUEOUS UREA SOLUTION

V. P. Korolev
Keywords: urea, alanine, aqueous solutions, partial volumes, hydration numbers
Pages: 176-180

Abstract >>
Literature data on the apparent molar volumes φ of alanine in water and aqueous urea solutions at 298 K are analyzed. It is shown that the slope of the φ dependence on the alanine concentration is not dependent on the urea concentration. The standard partial volume of alanine increases linearly with the increase in the urea concentration (wt.%). The structural characteristics of hydrated complexes of alanine (hydration number, molar volume of water inside and outside the hydration sphere, and proper volume of alanine in solution) are given. The hydration number of alanine decreases by a factor of two in passing from water to a saturated (20m) urea solution. The effects of urea additions on the hydration numbers of alanine and glycine are compared.
																								



24.
A 2D BITRIAZOLE-BRIDGING COPPER(II) POLYMER: HYDRO THERMAL SYNTHESIS, CRYSTAL STRUCTURE, AND FLUORESCENCE

L. Xu, X.-CH. Zhang, W.-G. Liu, B. Liu
Keywords: copper(II), crystal structure, fluorescence, 1, 2, 4-triazole
Pages: 181-185

Abstract >>
A new 2D metal-organic coordination polymer [Cu(trtr)2]n (1) (Htrtr = 3-(1,2,4-triazolyl-4-yl)-1H-1,2,4-triazole) is synthesized through the hydrothermal reaction of Cu(ClO4)2 with Htrtr. The crystal structure of 1 is determined by a direct method from X-ray diffraction data (Rigaku Mercury CCD, MoKα radiation). 1 crystallizes in the monoclinic C2/c space group with unit cell parameters: a = 14.158(2) Å, b = 9.8050(14) Å, c = 11.413(3) Å, β = 127.9870(10), v = 1248.7(4) Å3, z = 4, Dcal = 1.775 g/cm3. 1 features a 2D grid based on the propagation of 28-membered rings, which is further fabricated into a 3D supramolecular framework via the hydrogen bond linkage. The fluorescence of 1 shows a blue emission at 441 nm with a 14 nm red-shift compared to that of free Htrtr, which can be assigned to LMCT.
																								



25.
[Ni(en)3](ReO4)2: SYNTHESIS, CRYSTAL STRUCTURE AND THERMAL PROPERTIES

E. A. Bykova, S. P. Khranenko, S. A. Gromilov
Keywords: nickel, rhenium, ethylenediamine, thermolysis, crystal chemistry, single crystal X-ray diffraction
Pages: 186-190

Abstract >>
The crystal structure of [Ni(en)3](ReO4)2 (en is ethylenediamine) is studied: a = 8.3997(2)Å, b = 15.6167(5) Å, c = 14.2406(4) Å, β = 100.378(1), V = 1837.46(9) Å3, P21/c space group, Z = 4, and dx = 2.673 g/cm3. It is shown that packing of the complex cations can be considered as single-layer pseudohexagonal. Thermal decomposition of the salt in a hydrogen atmosphere at 550C is used to obtain a mixture of nickel with a nanocrystalline Re0.87Ni0.13 solid solution (a = 2.733(2) Å, c = 4.400(3) Å, 63/mmc space group; CSR size is ~14 nm).
																								



26.
STRUCTURE OF TETRA(3,5-DINITROBENZOATE) BIS(PIPERIDINE) HEXAAQUANICKEL(II) -[Ni(OH2)6](PipH)2(3,5-DNB)42H2O DIHYDRATE

É. B. Miminoshvili, K. É. Miminoshvili, T. N. Sakvarelidze
Keywords: complex compounds, synthesis, structural analysis, transition metals, piperidine, dinitrobenzoate
Pages: 191-195

Abstract >>
It is found that M(AmH)2(3,5-DNB)48H2O compounds (where M(II) = Co, Ni; AmH is piperidine PipH = (C5H10NH2)+ or diethylamine DaH = (C4H10NH2)+ cations; 3,5-DNB = (C7H3N2O6)- is the dinitrobenzoic acid anion) are isotypic. The structure of the Ni(PipH)2(3,5-DNB)48H2O single crystal is studied. The crystals have a monoclinic system, P21/n space group, Z = 2, a = 6.7694(3) Å, b = 16.0746(6) Å, c = 23.1250(9) Å, β = 97.794(1), V = 2493.1(2) Å3, T = 153 K. The final value R(F) = 0.0407 was obtained for 8191 independent reflections with I > 2σ(I). The structural units of the compound studied are as follows: [Ni(OH2)6]2+ complex hexaaquacation, two (PipH)+ cations, four (3,5-DNB)- anions, and two molecules of water of crystallization with the structural formula [Ni(OH2)6](PipH)2(3,5-DNB)42H2O. Similar compounds of Ni(II) and Co(II) are isostructural.
																								



27.
CRYSTAL AND MOLECULAR STRUCTURE OF THE COMPLEX OF 2-(1-SILATRANYLMETHYLTHIO)-4,5-BENZO-1,3-THIAZOLE WITH l2 AND MeCN

M. G. Voronkov, É. A. Zel'bst, A. D. Vasiliev, A. S. Soldatenko, Y. I. Bolgova, O. M. Trofimova
Keywords: 2-(1-silatranylmethylthio)-4, 5-benzo-1, 3-thiazole, acetonitrile, molecular structure, single crystal X-ray diffraction analysis
Pages: 196-199

Abstract >>
The crystal and molecular structure of the complex of 2-(1-silatranylmethylthio)-4,5-benzo-1,3-thiazole with l2 and MeCN (I) is determined by single crystal X-ray diffraction. The geometry of the silatranylmethyl moiety in complex I is compared to the geometry of 1-(2′-benzthiazolylthiomethyl)silatrane. Molecular packing in the crystal is analyzed.
																								



28.
CRYSTAL STRUCTURES OF TWO SOLVATES OF MOLYBDENUM OCTAHEDRAL CLUSTERS: (Bu4N)2[Mo6Cl8(O3SC6H4CH3)6]2CH3CN AND (Bu4N)2[Mo6Cl8(O3SC6H4CH3)6]2CH2Cl2

M. N. Sokolov, . . Mikhailov, P. A. Abramov, V. P. Fedin
Keywords: clusters, molybdenum, chlorides, p-toluenesulfonates, crystal structures, solvates
Pages: 200-204

Abstract >>
Crystal structures of two solvates (Bu4N)2[Mo6Cl8(O3SC6H4CH3)6]2CH3CN (1) and (Bu4N)2[Mo6Cl8(O3SC6H4CH3)6]2CH2Cl2 (2) are determined. Both compounds contain cluster [Mo6Cl8(O3SC6H4CH3)6]2- anions. Molybdenum atoms are coordinated with monodentate carboxylate ligands (Mo-O 2.101(3)-2.110(3) Å in 1; 2.088(7)-2.109(2) Å in 2).
																								



29.
MOLECULAR and CRYSTAL STRUCTURE of 4-trifluoro-2-[2-(4-fluorophenyl)hydrazine-1-ylidene]-1-(thiophen -2-YL)butane-1,3-dione

A. M. Magerramov, R. A. Alieva, V. I. Mardanova, F. M. Chyragov, A. V. Kurbanov, K. A. Potekhin
Keywords: single crystal X-ray diffraction, crystal structure, ?-diketone, 4-trifluoro-2-[2-(4-fluorophenyl)hydrazine-1-ylidene]-1-(thiophen-2-yl)butane-1, 3-dione
Pages: 205-208

Abstract >>
Single crystal X-ray diffraction is used to determine the crystal and molecular structure of 4-trifluoro-2-[2-(4-fluorophenyl)hydrazine-1-ylidene]-1-(thiophen-2-yl)butane-1,3-dione. Crystallographic data for C14H8F4N2O2S are as follows: a = 8.2723(6) Å, b = 9.3009(7) Å, c = 9.9895(7) Å; α = 79.224(2), β = 75.851(2), γ = 72.337(2). Triclinic crystal system, P-1 space group, dx = 1.622 g/cm3, V = 704.83(9) Å3, μ = 0.286 mm-1, crystal size 0.30×0.20×0.20 mm, R1 = 0.0891, wR2 = 0.1989.
																								



30.
CRYSTAL STRUCTURE of (2,2-DIMETHYL-3-METHYLIDENENORBONANE)TRIETHYL-PHOSPHONIUM PERCHLORATE

V. A. Zagumennov, N. A. Sizova, O. A. Lodochnikova, I. A. Litvinov
Keywords: Single crystal XRD is used to analyze the crystal structure of triethylcamphenylphosphonium salt produced during the electrochemical oxidation of triethylphosphine in the presence of camphene, single crystal XRD, phosphonium salts, terpenes, camphene, tri
Pages: 209-211