Publishing House SB RAS:

Publishing House SB RAS:

Address of the Publishing House SB RAS:
Morskoy pr. 2, 630090 Novosibirsk, Russia

Log In   /  Register




Advanced Search

2009 year, number 6

1.
RELATIONSHIP BETWEEN THE BOND LENGTHS IN N-HN, O-HO, F-HF, AND Cl-HCl HYDROGEN BRIDGES

E. G. Tarakanova, G. V. Yukhnevich
Keywords: hydrogen bridge, H-bond length, quantum-chemical calculation
Pages: 1063-1069

Abstract >>
The applicability of the equation e-((r1-r0)/b)5/3 + e-((r2-r0)/b)5/3 = 1 has been studied. The equation defines the relationship between the experimental values of the covalent (r1) and hydrogen (r2) bond lengths in O-HO bridges for describing the relation between the experimental interatomic distances in N-HN bridges and the parameters of X-HX fragments (X = O, N, F, Cl) calculated by the density functional method (B3LYP/6-31++G(d,p)) for neutral, positive, and negative molecular complexes. Here r0 is the mean value of the X-H bond length in free molecules; rsym is the XH distance in the symmetrical bridge; and b is the coefficient defined by the equation b = (rsym - r0)/(ln2)3/5. This equation allows us to adequately describe the relationships between bond lengths in nearly linear hydrogen bridges formed by oxygen, nitrogen, fluorine, and chlorine atoms. It is thus universal and can be used in studies of a wide range of substances.



2.
THE NATURE OF THE ELECTRONIC STATES AND PHOTOELECTROn SPECTRA OF OXYANION CRYSTALS

Y. N. Zhuravlev, D. V. Korabelnikov
Keywords: nitrites, nitrates, sulfites, sulfates, chlorates, perchlorates, densities of states, Mulliken population, charged state, partial charge, photoelectron spectrum
Pages: 1070-1077

Abstract >>
The densities of states, atomic charges, and partial components were calculated by the B3LYP method for lithium, sodium, and potassium nitrites, nitrates, chlorates, perchlorates, sulfites, and sulfates using a localized basis of atomic orbitals and CRYSTAL06 software. The calculated densities of states N(E) are in good agreement with the experimental photoelectron spectrum (UPS). The crystallographically nonequivalent metal and oxygen atoms are in different charged states, which leads to a splitting of the N(E) bands.



3.
FREE ELECTRON MODEL FOR HETEROATOMIC CONJUGATE MOLECULES

G. B. Litinskii, V. E. Krikunova
Keywords: free electron model, heteroatomic conjugate molecules, energy spectrum
Pages: 1078-1083

Abstract >>
A simple generalization of the free electron model is suggested for describing the heteroatomic conjugate molecules and obtaining analytical equations for the energy levels of these systems. The δ-like potential is used as a potential of a heteroatom in this model, and the energy levels are obtained as corrections for first order perturbation theory.



4.
STRUCTURE AND ENERGETICS OF β-DIKETONATES. XVI. MOLECULAR STRUCTURE AND VIBRATIONAL SPECTRUM OF ZINC ACETYLACETONATE ACCORDING TO GAS-PHASE ELECTRON DIFFRACTION AND QUANTUM-CHEMICAL CALCULATIONS

E. V. Antina, N. V. Belova, M. B. Berezin, G. V. Girichev, N. I. Giricheva, A. V. Zakharov, . . Petrova, S. A. Shlykov
Keywords: gas-phase electron diffraction, quantum chemistry, mass spectrometry, zinc acetylacetonate, molecular structure, vibration frequencies
Pages: 1084-1094



5.
MOLECULAR STRUCTURES AND THERMOCHEMISTRY OF THE DERIVATIVES OF C24 FULLERENE BY ATTACHING A VARIETY OF CHEMICAL GROUPS

S. Peng, X.J. Li, Y. Zhang, S. Zhao
Keywords: C24 fullerene, derivative, structure, thermochemistry, DFT
Pages: 1095-1101

Abstract >>
A series of exohedrally functionalized derivatives of the D6-symmetrical C24 fullerene, with attached -CH2OH, -CONH2, -COOH, and -COH chemical groups, have been investigated by using density-functional theory approach at the UB3LYP/6-31G(d) level. According to the calculated results, the C24(COOH) is the most stable structure, with -73.58 kcal mol-1 value for the functionalization reaction energy and 3.16 eV for the dissociation energy, while C24(CONH2) displays the largest dipole moment (3.09 D). It was also found that the HOMO-LUMO energy gaps, the vertical ionization potentials (VIP), and vertical electron affinities (VEA) of these functionalized derivatives are similar to those of the more stable C24 fullerene. Moreover, their corresponding HOMO and LUMO orbitals are mainly associated with the surface of the cage. Also, the vibrational frequencies of these derivatives are discussed. It was concluded that it would be possible to produce novel species for bio-medical applications by attaching selected chemical groups.



6.
Changes in the vibrational characteristics of substituted 1,2,4,5-tetrazines after complexation with 1,2,3-benzotriazole: a theoretical study

N. N. Ivshina, E. V. Bartashevich, V. A. Potemkin, M. A. Grishina, R. I. Ishmetova, G. L. Rusinov, N. I. Latosh, P. ??. Slepukhin, V. N. Charushin
Keywords: 1,2,4,5-tetrazines, IR spectroscopy, stretching vibration frequencies, molecular co-crystals, hydrogen bond
Pages: 1102-1107

Abstract >>
The complexation of 3,6-substituted 1,2,4,5-tetrazines with benzotriazole was studied theoretically based on the vibrational spectra. For model complexes, the energy was minimized by the geometrical parameters, and the spectral characteristics were calculated by the PM3 method. The shift of the bond vibration frequencies of the atoms involved in complexation after the formation of different various intermolecular contacts was determined. This made it possible to determine the type of intermolecular interaction and suggest the structures of the complexes.



7.
TEMPERATURE EFFECTS ON THE IR SPECTRA OF CRYSTALLINE AMINO ACIDS, DIPEPTIDES, AND POLYAMINO ACIDS. V. L-SERYLGLYCINE

G. B. Chernobay, Y. A. Chesalov, E. V. Boldyreva
Keywords: peptide bond, dipeptides, L-serylglycine, hydrogen bond, IR spectroscopy
Pages: 1108-1114

Abstract >>
The IR spectra of L-serylglycine (HN-H(CH2-OH)-O-NH-H2-OO-), recorded at 413-93 K, have been studied, and the observed frequencies were assigned. Based on the results, we concluded that the stability of hydrogen bonds in the structure changed as a result of variation of temperature. The conclusions were compared with the results of IR spectroscopic studies of the crystals of α-glycylglycine, DL-serine, and glycine under the similar conditions.



8.
PHYSICOCHEMICAL STUDIES OF THE STRUCTURE OF N,N′-DINITROUREA AND ITS SALTS

S. G. Il'yasov, . . Lobanova, I. Y. Bagryanskaya, T. V. Rybalova, Y. V. Gatilov
Keywords: dinitrourea, tautomeric forms, potassium salts, IR, UV, XRD, quantum-chemical calculations
Pages: 1115-1120

Abstract >>
The properties and behavior of dinitrourea and its potassium and dipotassium salts in different solvents have been studied by IR and UV spectroscopy. In different media, dinitrourea can exist in several tautomeric forms. An XRD study of the potassium and dipotassium salts of dinitrourea revealed a tendency toward equalization of the bond lengths of the C-N--NO2 fragments compared with those of C-NH-NO2, which agrees with the results of quantum-chemical calculations.



9.
HINDERED INTERNAL ROTATION OF THE CF3 GROUP IN THE 2-TRIFLUOROMETHYLNITROBENZENE RADICAL ANION IN DMF:H2O MIXTURES

L. A. Shundrin, P. V. Melnikov, . . Polenov
Keywords: radical anions, hindered rotation, internal rotation, EPR spectroscopy, nitrobenzene
Pages: 1121-1131

Abstract >>
The temperature dependences of the EPR spectrum of the 2-trifluoromethylnitrobenzene radical anion in DMF:H2O mixtures, caused by the dynamic modulation of the fluorine isotropic hyperfine interaction by the hindered internal rotation of the CF3 group, have been measured and reconstructed numerically. The activation energy of rotation (EF) and the dynamic mode depended on the water content in the mixture. For mixtures with a molar fraction of water χ = 0, 0.186, 0.315, 0.409, 0.534, 0.650, 0.810, and 0.910, EF = 34.70 kJ/mol, 41.31 kJ/mol, 42.30 kJ/mol, 38.41 kJ/mol, 37.01 kJ/mol, 34.51 kJ/mol, 24.10 kJ/mol, and 21.78 kJ/mol, respectively. For χ = 0.186 in the temperature ranges accessible for measurements, the dynamic exchange is slow; for χ = 0.315, 0.409, 0.534, and 0.650, transitions from slow to intermediate and fast exchange take place; for χ = 0.810 and 0.910 in the temperature ranges under study T∈[252, 309]; [254, 297] (K), the exchange is fast. In the range 0.6 < χ < 0.9, EF decreased drastically, and the activation energy of rotational diffusion (Er) of the radical anion became maximum, which corresponds to the range of the compositions of DMF:H2O with maximum deviations from the ideal state.



10.
EuroPt-1 CATALYST: RADIAL DISTRIBUTION OF ELECTRON DENSITY X-RAY DIFFRACTION AND EXAFS STUDIES

. M. Moroz, V. V. Kriventsov, D. I. Kochubei
Keywords: EXAFS, catalyst, platinum, oxide, structure
Pages: 1132-1138

Abstract >>
The supported Pt/SiO2 (EuroPt-1) catalyst has been studied by the radial distribution of electron density (RDED) and EXAFS techniques. The starting sample of the catalyst was stored in air, not subjected to any further treatment, and contained metal platinum Pt0 and platinum oxide PtO in a ~1:2 ratio. An analysis of the EXAFS data was based on three possible structural models of platinum particles. Model 1 suggested that there was one Pt-Pt short contact, which was the same in the bulk of the particles and on the surface. Model 2 considered two different Pt-Pt distances for the particle volume and surface. For model 3, we additionally assumed that the corresponding Debye-Waller factors differed. For the oxidized sample, model 2 was most reliable, and the Pt-Pt distance between the surface atoms was shortened by ~0.14 Å. For the reduced samples, the structural data obtained are consistent with model 3.



11.
STRUCTURAL CHARACTERISTICS OF DICARBON POLYFLUORIDE

V. G. Makotchenko, A. S. Nazarov
Keywords: graphite, fluorooxidant, intercalated compounds, dicarbon polyfluoride, degree of ionicity
Pages: 1139-1146

Abstract >>
In chemical analysis and XRPA studies, it has been found that the products of fluorination of graphite, graphite bifluoride, and tetracarbon polyfluoride with gaseous and liquid fluorooxidants (ClF3, ClF5, XeF2, and FNO3) and their solutions in anhydrous hydrogen fluoride and freon-113 at 20-100C, having a limiting composition, are second stage intercalated compounds based on dicarbon polyfluoride with the corresponding fluorooxidant, or the reduced form of fluorooxidant, or a fluorooxidant and a solvent. The degree of C-F bond ionicity in C2F was higher than in CF, but lower than in C4F. However, the bond is closer in character to the covalent C-F bond in monocarbon polyfluoride.



12.
CONCENTRATION, TEMPERATURE, AND ISOTOPY EFFECTS ON THE HEAT CAPACITY OF AQUEOUS UREA

V. P. Korolev
Keywords: urea, aqueous solutions, heat capacity
Pages: 1147-1154

Abstract >>
Relations for the apparent molar heat capacity φ of urea in an aqueous solution depending on the molality m and temperature were obtained. A transition to the relations φ(m,T) for D2O-(ND2)2CO and 2O-(N2)2CO systems was effected by temperature scaling. At low temperatures, the isotherms of the molar heat capacity Cp(m) of the protium and deuterium systems have minima shifted to more dilute solutions at elevated temperatures. At m = 1, Cp of a solution does not depend on temperature in both systems. The dependences Cp(T) also have minima at constant concentrations. The temperature of the minimum heat capacity is most effectively lowered by small additions of urea. For m = 0.25, Tmin is 7.5 K lower than Tmin of pure water, and its heat capacity is 0.08 J/(mol K) higher. A transition from m = 1.5 to m = 2 lowers the temperature of the minimum heat capacity by 3.6 K; thus, the heat capacity of solutions differs by 0.02 J/(mol K) only.



13.
HYDRATION EFFECT ON THE STABILITY OF THE KETO-ENOL TAUTOMERS OF 5-HYDROXY-6-METHYLURACIL

I. F. Dautova, S. P. Ivanov, S. L. Khursan
Keywords: quantum chemical calculation, 5-hydroxy-6-methyluracil, tautomer, hydration, hydrogen bond
Pages: 1155-1165

Abstract >>
The structure and energies of six tautomeric forms of 5-hydroxy-6-methyluracil (OMU) and their 1:n (n = 1-4) complexes with water were determined by the density functional theory (PBE/3z) method. The stability series of the tautomers and changes in it depending on the number of water molecules in the nearest environment of the tautomer were found. The effect of the water solvent was also included using the continuum (B3LYP/6-311+G(2d,p), COSMO) model. Both complex formation and medium effects significantly influenced the stability series of the tautomers. Although the decrease in the energy of the diketo form on hydration was smaller than for the enol states, diketo tautomer a remained the most stable form of OMU in solution. Inclusion of hydration in calculations suggests that the energies of three enol tautomers b-d were equalized (ΔH ≈ 5.5 kJ/mol). This should be taken into account for the conditions that facilitate the keto-enol tautomerism of OMU.



14.
STRUCTURES WITH VACANCY SUBLATTICES BASED ON FCC AND BCC PACKINGS OF SPHERES AND THEIR STABILITY AT NEGATIVE PRESSURES

V. I. Kosyakov, V. A. Shestakov
Keywords: vacancies, vacancy clusters, sphere packings, thermodynamic stability, negative pressure, homologous series, simulation, structural characteristics
Pages: 1166-1173

Abstract >>
Structures with regular sublattices of vacancies, vacancy clusters, and channels constructed from the fcc and bcc packings of spheres were analyzed. Homologous series of structures were constructed, and formulas were derived to correlate the basic structural characteristics with the composition of the "vacancy compounds" AmVn. The thermodynamic stabilities of structures with vacancies were compared with the stability of a flaw-free structure in the range of negative pressures using the simple interatomic interaction potential. Structures with vacancy clusters and channels may be more stable than the ideal structure in a certain range of pressures. This paper summarizes the results of simulations of structures with vacancy sublattices based on close packings of spheres described in this work and previous publications and their thermodynamic stability at negative pressures.



15.
X-RAY STUDY OF THE THERMOLYSIS PRODUCTS OF (NH4)2[OsCl6]x[PtCl6]1-x

S. A. Gromilov, Y. V. Shubin, A. I. Gubanov, E. A. Maksimovskii, S. V. Korenev
Keywords: platinum, osmium, complex salt, solid solution, polycrystal, X-ray study, pseudomorphism
Pages: 1174-1178

Abstract >>
Thermolysis of the complex salts (NH4)2[OsCl6]x[PtCl6]1-x ( = 0.25-0.9) formed nanocrystalline OsxPt1-x phases. Pseudomorphism has been found: the habit of the single crystals of the starting salts is preserved during thermolysis, and the ~10-20 nm metal particles are agglomerated into octahedral structures sized 5-10 μm.



16.
STRUCTURE OF RHENIUM COATINGS OBTAINED BY CVD

N. V. Gelfond, N. B. Morozova, E. S. Filatov, S. A. Gromilov, I. K. Igumenov
Keywords: Re coatings, X-ray diffraction, scanning electron microscopy, chemical vapor deposition (CVD), dirhenium decacarbonyl, cyclopentadienyl rhenium tricarbonyl
Pages: 1179-1186

Abstract >>
By chemical vapor deposition in the hydrogen atmosphere from Re2(CO)10 and Re(CO)3(Cp) on steel and ceramic (/SiC) substrates, rhenium coatings are obtained with an average thickness of 3-13 μm, when Re2(CO)10 is used, and of 2-8 μm when depositing from Re(CO)3(Cp). The coatings are studied by X-ray diffraction and scanning electron microscopy. It is shown that when Re2(CO)10 is used, an increase in the deposition temperature results in the growth of textured coatings with preferred orientation of crystallites in the [0 0 2] direction. At the same time, a tendency for decreasing the size of rhenium crystallites is observed. With the change of evaporator temperature, the structure of Re coatings obtained from Re(CO)3(Cp) on steel substrates changes considerably: from compact non-layered without the obvious growth direction (Tevaporator = 120C) to a three-layer structure, where the initial layer has a compact structure followed by columnar and powdered layers (Tevaporator = 110C). A fine compact coating is formed on ceramic substrates at an evaporator temperature of 110C.



17.
X-RAY STUDY OF RHODIUM(III) SULFATES

S. N. Vorob'yova, I. A. Baidina, A. V. Alekseev, A. V. Belyaev
Keywords: rhodium, sulfates, aqua complexes, coordination compounds, crystal structure
Pages: 1187-1195

Abstract >>
Compounds with compositions [Rh(H2O)6]2(SO4)34H2O (I), (H3O)[Rh(H2O)6](SO4)2 (II), [Rh(H2O)5OH](SO4)0.5H2O (III), and [Rh(H2O)6]2(SO4)(H2SO4)x5H2O (IV) have been studied. The crystal structures of II, III, and IV were determined. All compounds crystallized in the monoclinic crystal system. Crystal data for II: a = 7.279(2) Å, b = 10.512(7) Å, c = 15.806(3) Å, β = 96.71(3), space group P21/n, Z = 2, dcalc = 2.334 g/cm3; III: a = 20.433(4) Å, b = 7.820(2) Å, c = 11.215(2) Å, β = 114.14(1), space group C2/c, Z = 8, dcalc = 2.559 g/cm3; IV: a = 6.2250(4 Å), b = 27.0270(12) Å, c = 7.2674(5) Å, β = 97.04(3), space group P21/c, Z = 4, dcalc = 2.143 g/cm3. The compounds were studied by IR spectroscopy and powder X-ray diffraction. All of the isolated crystalline phases are sparingly soluble in ethanol and well soluble in water.



18.
CRYSTAL AND MOLECULAR STRUCTURES OF BINUCLEAR COMPLEXES OF SALYCILIC ACID {Cu-} ( = Cu, Sr, )

V. V. Gorincioy, Y. A. Simonov, S. G. Shova, V. N. Shofranskii, C. I. Turta
Keywords: synthesis, homo- and hetero-binuclear salicylates, copper, X-ray crystallography
Pages: 1196-1202

Abstract >>
Heterometallic complexes [uSr(SalH)4(DMAA)4(H2O)] (II) and [CuBa(SalH)4(DMAA)4 (H2O)] (III) were synthesized by interaction of salicylates of s elements with copper nitrate. A mixture of III and vanadyl sulfate yielded the crystals of a homonuclear complex [CuCu(SalH)4(H2O)2]2DMAA (I). According to single crystal X-ray data, all of the products are of lantern type and belong to two space groups: I is triclinic, space group P-1, unit cell parameters a = 9.9083(2) Å, b = 10.5077(3) Å, c =10.9512(3) Å, α = 112.736(2), β = 114.0800(10), γ = 93.131; II and III are tetragonal, space group P4/n, lattice parameters a = b = 16.3180(3) Å, c = 8.7838(2) Å for II and a = b = 16.362(3) Å, c =8.920(1) Å for III. The copper atoms have a square-pyramidal environment. The coordination number of Sr and Ba is 8, and the coordination polyhedron can be represented as a Thomson cube in both cases. The carboxylic groups are coordinated in a syn-syn bridging mode. The oxygen atom of the hydroxyl group of salicylic acid is not involved in coordination, but forms intramolecular hydrogen bonds to the carboxylic groups. The hydrogen bonds between water and DMAA solvate molecules, as well as π-π interactions between the aromatic fragments of the dimers, play a particularly important role in the molecular packing in crystal.



19.
CRYSTAL STRUCTURES OF ALKALOID PEGANINE AND ITS COCRYSTAL WITH PEGANOL

R. Y. Okmanov, A. G. Tozhiboev, K. K. Turgunov, B. Tashkhodzhaev, Z. M. Khakimova, T. S. Tulyaganov, K. M. Shakhidoyatov
Keywords: quinazolines, peganine, peganol, salts, cocrystals, X-ray diffraction
Pages: 1203-1208

Abstract >>
X-ray diffraction (XRD) is used to investigate the crystal structures of the alkaloid peganine, its hemihydrate and nitrate. It is shown that ()-peganine forms a cocrystal with the alkaloid peganol. It is typical of the alkaloid (-)-peganine crystal structures to form a closed dimer pair because of reciprocal O-ͅN1 hydrogen bonds. Analogous H-bonds are also observed in the ()-peganine-()-peganol cocrystal, where the center of symmetry binds together similar molecules to form associates. In ()-peganine nitrate crystals, the NH+ and groups of the alkaloid form H-bonds simultaneously with two oxygen atoms of nitric acid anions.



20.
Structure and magnetic properties of THE pentanuclear complex [Fe2(CN)12Ni3(L)6]27H2O, where L is nitronyl nitroxide

H. Higashikawa, K. Inoue, K.YU. Maryunina, G.V. Romanenko, A.S. Bogomyakov, O.V. Kuznetsova, E.YU. Fursova, V.I. Ovcharenko
Keywords: nickel, iron, cyano bridge, nitroxide, pentanuclear complex, crystal structure, magnetic properties
Pages: 1209-1212

Abstract >>
We succeeded in synthesizing a new high-spin complex [Fe2(CN)12Ni3(L)6]27H2O, where L is stable nitroxide 2-(imidazol-4-yl)-4,4,5,5-tetramethyl-2-imidazoline-3-oxide-1-oxyl. According to X-ray diffraction data, the metal core of the pentanuclear [Fe2(CN)12Ni3(L)6] molecule is a trigonal bipyramid with Fe atoms occupying the axial positions and linked via CN bridges to {NiL2} fragments laying in the equatorial plane. A peculiarity of this coordination compound is a large number of water molecules per the [Fe2(CN)12Ni3(L)6] pentanuclear molecule in the structure. The complex character of the μeff(T) dependence points to many competing channels of exchange interactions between the three types of paramagnetic centers.



21.
Structural tautomerism of 4-acylpyrazolone Schiff bases and crystal structure of 5-methyl-2-phenyl-4-{1-[(pyridin-2-ylmethyl)-amino]-ethylidene}-2,4-dihydro-pyrazol-3-one

A.S. Amarasekara, O.S. Owereh, K.A. Lyssenko, T.V. Timofeeva
Keywords: 4-acylpyrazolone, Schiff-base, tautomerism
Pages: 1213-1218

Abstract >>
The Schiff base derivatives prepared from 4-acetyl-5-methyl-2-phenyl-2,4-dihydro-pyrazol-3-one and alkyl amines are shown to remain exclusively in the amine-one(I) tautomeric form in chloroform solutions at room temperature using a combination of 1H, 13C, APT, COSY, HMQC, and HMBC NMR spectroscopic methods. The crystal structure of 5-methyl-2-phenyl-4-{1-[(pyridin-2-ylmethyl)-amino]-ethylidene}-2,4-dihydro-pyrazol-3-one showed that this
4-acylpyrazolone Schiff base stays in the amine-one(I) form in the solid state as well, and the solid state structure supports the fact that strong hydrogen bonding between amine hydrogen and the pyrazolone C3 carbonyl oxygen helps to stabilize the amine-one(I) tautomer.



22.
CRYSTAL STRUCTURE AND PROPERTIES OF (Z)-N?-((E)-2-(HYDROXYIMINO)-1-PHENYLETHYLIDENE)ISONICOTINOHYDRAZIDE

A. Zulfikaroglu, . Yksektepe, H. Bati, N. Caliskan, O. Buyukgungor
Keywords: pyridine, oxime, hydrazone, twin crystal, isomerism
Pages: 1219-1222

Abstract >>
Compound I contains in its molecule pyridyl, monoxime and hydrazone functions. A non-merohedral twin crystal of the compound with two reciprocal lattices differently oriented and giving rise to double diffraction spot sets with the 0.5:0.5 ratio of the twin components was studied. The hydrazone and oxime units are approximately planar. The dihedral angles between this plane and the planes of the pyridine and phenyl rings are 30.79(19) and 18.43(13), respectively. Both the oxime and hydrazone units in I have an E configuration. The molecules of I are linked via C-HO and O-HN hydrogen bonds forming a 3D framework. The compound was also characterized by IR, 1H NMR and elemental analyses.



23.
STUDY ON THE FREE SURFACE ENERGY PER UNIT AREA OF ALUMINIUM NANODROPS USING THE SCHOMMERS POTENTIAL

N. Y. Sdobnyakov, A. N. Bazulev, V. M. Samsonov, D. A. Kul'pin, D. N. Sokolov
Keywords: thermodynamic perturbation theory, metal nanodrops, Schommers, Morse, and Schiff molecular interaction potentials, size dependence of the surface tension, stability
Pages: 1223-1228

Abstract >>
Based on thermodynamic perturbation theory, we calculate the surface tension for aluminium nanodrops of various radii. The size dependence obtained with the Schommers potential is compared with the results corresponding to other effective pair potentials. It is stated that the asymptotic value of the surface tension of large nanodrops produced by the Schommers potential is better consistent with the existing experimental data.



24.
Role of Sublattices in the Formation of the Chemical Bond in Ion-Covalent Crystals

Y. M. Basalaev, A. S. Poplavnoi
Keywords: sublattice method, density functional, chalcopyrite
Pages: 1229-1232

Abstract >>
Crystals of ZnGeAs2 and AgGaTe2 are used as examples to show the results of applying the sublattice method. The latter enables one to visualize the formation of valence band structure, electron density and chemical bond as a result of interactions between the atoms in various sublattices of the crystal.



25.
ISING-LIKE HAMILTONIAN AND FREE ENERGY FUNCTIONAL: TWO FUNDAMENTALLY DIFFERENT MODELS OF SPIN CROSSOVER

A. B. Koudryavtsev, W. Linert
Keywords: spin crossover, Ising-like potential model, molecular statistical model
Pages: 1233-1237

Abstract >>
The theoretical models of spin crossover (equilibrium between the high- and low-spin isomers of transition metal complexes) are compared. The models yield similar descriptions of the one-step spin crossover, but different descriptions of the two-step transition curves because of different approaches to the calculation of molecular interactions. The parameters of the Ising-like Hamiltonian reflect the lattice response to the distribution of molecules, and the parameters of the free energy functional reflect the molecular interactions, due to which the sharpness of transition can be correlated with the molecular properties.



26.
Interaction of Phenols with Ovalbumin by NMR Data

L. N. Kurkovskaya, I. I. Levina
Keywords: phenols, ovalbumin, H-bond, NMR method
Pages: 1238-1239

Abstract >>
NMR data are used to determine the type of preferred interaction of phenol derivatives with ovalbumine. Hydrogen bonding of an OH-phenol group with protein aminoacids is followed by the precipitation of a solid complex. The rate of this process depends on the substituent in the benzene ring.



27.
BEHAVIOR OF OF AQUEOUS UREA NEAR THE SINGULARITY POINT

V. P. Korolev
Keywords: urea, aqueous solutions, volumetric properties
Pages: 1240-1244

Abstract >>
Equations for the apparent molar volume φ of urea in aqueous solution were obtained. In contrast to [3, 4], according to the new relations here, φ remains finite at a singularity temperature Ts, and φ0 = 0. At T Ts, the partial expansibility is finite, whereas the thermal coefficient → +∞. A transition to calculation of the volumetric characteristics of the D2O-(ND2)2CO and 2O-(N2)2CO systems is done by temperature scaling.



28.
STRUCTURE AND MAGNETIC PROPERTIES OF Cu(II) BISCHELATE WITH SPIN-LABELED AMINOENAL

E. V. Tret'yakov, O. V. Koreneva, G. V. Romanenko, A. S. Bogomyakov, V. I. Ovcharenko, R. Z. Sagdeev
Keywords: nitronyl nitroxides, copper (II) complexes, crystal structure, magnetic properties
Pages: 1245-1248

Abstract >>
The molecular and crystal structure of Cu(II) bischelate with the deprotonated stable nitroxide radical 4,4,5,5-tetramethyl-2-(2-oxo-1-(4,4,5,5-tetramethylimidazolidine-2-ylidene)ethyl)-4,5-dihydro-1H-imidazole-3-oxide-1-oxylom (HL) are studied. It is revealed that the complex packing is formed of separate CuL2 molecules. Oxygen atoms in >N∂O groups do not participate in Cu2+ ion coordination, and so only weak exchange interactions are observed between paramagnetic centers in CuL2.



29.
SYNTHESIS AND CRYSTAL STRUCTURE OF THE OCTAHEDRAL CYANO-BRIDGED CLUSTER COMPLEX β-[{Ni(NH3)5}2{Re6Te8(CN)6}]4H2O

K. A. Brylev, Y. V. Mironov, V. E. Fedorov
Keywords: octahedral cluster, rhenium, nickel, synthesis, crystal structure
Pages: 1249-1252

Abstract >>
The rhenium cyano-bridged cluster complex with a composition of β-[{Ni(NH3)5}2{Re6Te8(CN)6}]4H2O is obtained and structurally characterized. The compound crystallizes in the triclinic space group with the unit cell parameters: a = 9.997(2) Å, b = 10.423(2) Å, c = 11.714(2) Å, α = 100.92(3), β = 111.87(3), γ = 98.05(3), V = 1082.1(4) Å3, Z = 1, dcalc = 4.072 g/cm3. The rhenium atoms of the {Re6Te8} cluster core are coordinated by CN ligands to form the [Re6Te8(CN)6]4- cluster; two nitrogen atoms of CN ligands trans-positioned with respect to each other are coordinated to Ni atoms in the {Ni(NH3)5}2+ fragments to form the molecular complexes of [{Ni(NH3)5}2{Re6Te8(CN)6}]. The crystal structure is the H-bonded packing of these molecular complexes and crystallization water molecules.



30.
CRYSTAL STRUCTURE OF [Cu(NH3)4](ReO4)2

S. P. Khranenko, E. A. Shusharina, S. A. Gromilov, A. I. Smolentsev
Keywords: copper, rhenium, complex, crystal chemistry, X-ray diffraction
Pages: 1253-1255

Abstract >>
At T = 150 K, the crystal structure of [u(NH3)4](ReO4)2 is studied: a = 6.5167(3) Å, b = 6.7790(3) Å, c =7.4627(3) Å, α = 67.336(1), β = 80.004(1), γ = 70.687(1), V = 286.70(2) Å3, P-1 space group, Z = 1, dx = 3.661 g/cm3. We analyze the packing of ions using the translation sublattice isolation technique.



31.
UNUSUAL MOLECULAR STRUCTURE OF (C=O→Si←O′=C′) BIS(2-METHYL-4-PYRONE-3-OXY)DIFLUORO(λ6)SILICONIUM

M. G. Voronkov, A. A. Korlyukov, . A. Zel'bst, E. A. Grebneva, O. M. Trofimova, M. Y. Antipin
Keywords: bis(2-methyl-4-pyrone-3-oxy)difluoro(?6)siliconium, molecular structure, X-ray diffraction
Pages: 1256-1259

Abstract >>
X-ray diffraction is used to determine the crystal and molecular structure of spirocyclic (=O→Si←
O′=C′) bis(2-methyl-4-pyrone-3-oxy)difluoro(λ6)siliconium containing a hypervalent silicon atom and the previously unknown F2SiO4 coordination center. The coordination polyhedron of the silicon atom is a slightly distorted octahedron.



32.
CRYSTAL AND MOLECULAR STRUCTURE OF 4,4′-BIPYRIDINIUM BIS(TRANS-2-HYDROXYCINNAMATE) BIS(4,4′-BIPYRIDINE)

Y.Y. Zhang, Y. Gio, H.X. Chen, W.J. Xu, Z.M. Jin
Keywords: whole molecule disorder, hydrogen bond, co-crystal, hydroxycinnamate, ortho-coumaric acid, 4,4?-bipyridine.
Pages: 1260-1263

Abstract >>
4,4′-Bipyridinium bis(trans-2-hydroxycinnamate) bis(4,4′-bipyridine), 0.5(C10H10N2)2+
(C9H7O3)-C10H8N2, crystallizes in triclinic system, space group P-1, with a = 7.4211(8), b = 9.9516(11), c = 13.8587(15) Å, β = 92.510(2), α = 96.772(2), γ = 99.164(2), V == 1001.33(19) Å3, ρcalc = 1.321 g/cm3, Z = 2. In the crystal, the whole trans-2-hydroxycinnamate is disordered over two sites with different occupancies. The molecular species are linked by O-HN and N-HO hydrogen bonds into five-molecule hydrogen bonded chain associates that are further linked by C-HO hydrogen bonds into layers with the major orientation of the disordered 2-hydroxycinnamate. However such hydrogen bonds are not observed with the minor orientation.



33.
HYDROTHERMAL SYNTHESIS AND CRYSTAL STRUCTURE OF [Zn(pytpy)2][NO3]22H2O

Yu Ding, Feng Wang, Zong-jun Ku, Lian-sheng Wang, Huan-bo Zhou
Keywords: pytpy, zinc complex, crystal structure, hydrothermal synthesis
Pages: 1264-1267

Abstract >>
The title compound, [Zn(pytpy)2][NO3]22H2O (pytpy = 4′-(4-pyridyl)-2,2′: 6′,2″-terpyridine), has been synthesized by the reaction of Zn(NO3)2∙6H2O with pytpy, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to tetragonal space group P43 with a = 0.90873(8), b = 0.90873(8), c = 4.4741(6) nm, V = 3.6946(7) nm3, Z = 4, Dc = 1.521 g/cm-3, μ = 0.736 mm-1, F(000) = 1744, R = 0.0871, wR = 0.1302 for 5553 observed reflections with I > 2σ(I). X-ray analysis has revealed that the ZnII ion is surrounded by six N atoms from two pytpy ligands leading to a distorted octahedral geometry. In the crystal structure there are numerous strong intermolecular and intramolecular H-bonds and π-π interactions.