Home – Home – Jornals – 2008 number 3

The structure of Nb₂Mo₃O₁₄ double oxide is refined from powder data using synchrotron radiation and the anomalous scattering effect; space group P2₁m is found for the material. It is demonstrated that in the tetragonal unit cell with parameters а = 23.173 Å, с = 4.0027 Å Nb⁵⁺ and Мо⁶⁺ ions are stochastically distributed in МО₆ octahedra and МО₇ pentagonal bipyramids of the polygonal network structure of the Мо₅О₁₄ type.

Four structural models of volborthite Cu₃(OH)₂(V₂O₇)⋅2H₂O (a = 10.646(2) Å, b = 5.867(1) Å, c =
14.432(2) Å, β = 95.19(1)°, V = 897.7(5) ų, Z = 4, R/R_w = 0.038/0.046) calculated in the space groups determined from the systematic absences are compared. Based on the structure balance and the similarity of constituting polyhedra, values of the R factor, and isotropic thermal parameters, the space group Ia is found to be preferable, which is the only possible asymmetric and uniform variant. Hydrogen atoms of ОН-groups, oxygen atoms and, partially, hydrogen atoms of water are localized.

A polyhydrate of the tetraisoamylammonium salt of linear (uncrosslinked) polyacrylate (~25 monomeric units in the polyacrylate chain) is described and compared to polyhydrates of cross-linked tetraisoamylammonium polyacrylates (0.5-3% of cross-linking with divinylbenzene or divinylsulfide). Powder X-ray diffraction reveals that the polyhydrate containing a linear polyacrylate molecule has the same structure (hexagonal, a = 12.26 Å, c = 12.71 Å at 3°C) as polyhydrates of the cross-linked polyacrylate molecules. A single crystal of the polyhydrate obtained from an aqueous solution of linear tetraisoamylammonium polyacrylate is studied by X-ray diffraction at -173°C. The structure is hexagonal; space group P-6m2; the polyhydrate framework is a slightly distorted variant of the hexagonal structure-I of clathrate hydrates.

The complex Ru₄(μ₄-S)(μ,η³-C₃H₅)₂(CO)₁₂ is prepared and examined by IR and NMR spectroscopy; its crystal structure is determined (an automatic Bruker-Nonius X8 Apex four-circle diffractometer equipped with a 2-D CCD-detector, 100 K, graphite-monochromated molybdenum source, λ = 0.71073 Å). The crystal belongs to the orthorhombic crystal system with unit cell parameters a = 19.3781(9) Å, b = 12.2898(7) Å, c = 10.1726(4) Å, V = 2422.6(2) ų, space group Pnma, Z = 4, composition C₁₈H₁₀O₁₂Ru₄S, d_x = 2.343 g/cm³. The molecule of point symmetry C₁ is situated on the mirror plane of the space group Pnma, two carbonyl groups at Ru2 and Ru3 atoms overlapping with the allylic ligand with a weight of 50% so that carbon atoms coincide. Thus, we have a racemic structure with two overlapping enantiomers of the molecule of Ru₄(μ₄-S)(μ,η³-C₃H₅)₂(CO)₁₂.

The title compounds, (NH₄)₂[Mn^II(edta)(H₂O)]⋅3H₂O (H₄edta = ethylenediamine-N,N,N′,N′-tetraacetic acid), (NH₄)₂[Mn^II(cydta)(H₂O)]⋅4H₂O (H₄cydta = trans-1,2-cyclohexanediamine-N,N,N′,N′-tetraacetic acid) and K₂[Mn^II(Hdtpa)]⋅3.5H₂O (H₅dtpa = diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid), were prepared; their compositions and structures were determined by elemental analysis and single-crystal X-ray diffraction technique. In these three complexes, the Mn²⁺ ions are all seven-coordinated and have a pseudo-monocapped trigonal prismatic configuration. All the three complexes crystallize in triclinic system in P-1 space group. Crystal data: (NH₄)₂[Mn^II(edta)(H₂O)]⋅3H₂O complex, a = 8.774(3) Å, b = 9.007(3) Å, c = 13.483(4) Å, α = 80.095(4)°, β = 80.708(4)°, γ = 68.770(4)°, V = 972.6(5) ų, Z = 2, D_c
= 1.541 g/cm³, μ = 0.745 mm^-1, R = 0.033 and wR = 0.099 for 3406 observed reflections with I ≥ 2σ(I); (NH₄)₂[Mn^II(cydta)(H₂O)]⋅4H₂O complex, a = 8.9720(18) Å, b = 9.4380(19) Å, c = 14.931(3) Å, α = 76.99(3)°, β = 83.27(3)°, γ = 75.62(3)°, V = 1190.8(4) ų, Z = 2, D_c = 1.426 g/cm³, μ = 0.625 mm^-1, R = 0.061 and wR = 0.197 for 3240 observed reflections with I ≥ 2σ(I); K₂[Mn^II(Hdtpa)]⋅3.5H₂O complex, a = 8.672(3) Å, b = 9.059(3) Å, c = 15.074(6) Å, α = 95.813(6)°, β = 96.665(6)°, γ = 99.212(6)°, V = 1152.4(7) ų, Z = 2, D_c = 1.687 g/cm³, μ = 1.006 mm^-1, R = 0.037 and wR = 0.090 for 4654 observed reflections with I ≥ 2σ(I).

The molecular structure of 1-methyl-1-fluoroquasisilatrane (2-methyl-2-fluoro-1,3-dioxa-6-aza-2-silacyclooctane) MeFSi(OCH₂CH₂)₂NH (I) is determined by single crystal X-ray diffraction at 100 K. The coordination polyhedron of the silicon atom in this molecule is a slightly distorted trigonal bipyramid with an NH group and a strongly electron-withdrawing fluorine atom in the axial positions, and two endocyclic oxygen atoms and a СН₃ group in three vertices of the equatorial plane. The axial angle N→SiF is 171°. The length of the transannular donor-acceptor bond N→Si (2.058 Å) is as small as in 1-fluorosilatrane. The axial bond F-Si (1.660 Å) is longer than that in 1-fluorosilatrane and tetrahedral silicon compounds.

In large-scale molecular objects (nanostructures) such as dendromers, supramolecules, polymers, nanotubes, etc. external perturbations may have local character. When the perturbation is removed, atomic wave motions of a rather complex type may arise in the nanostructure. They can not only transfer signals inside the nanoobject, but also generate standing waves and antinodes and accumulate energy in other domains of the nanostructure, i.e., give rise to energy traps. These problems have not been addressed before. In this paper we propose a method to calculate the time-dependent evolution of these phenomena for large-scale molecular structures of arbitrary structure and size.

X-ray diffraction analysis of four perfluorinated homophthalic (2-carboxymethylbenzoic) acids is carried out. In the crystals of 2-carboxymethyl-3,4,5,6-tetrafluorobenzoic acid (1) the chains (1D architecture) form with the usual dimeric carboxylic C(O)OH:::O(HO)C synthon. The aromatic carboxylic group is disordered in the ratio 0.58:0.42 over two positions. In the crystals of 2-(carboxydifluoromethyl)-3,4,5,6-tetrafluorobenzoic (2) and 2-(1-carboxy-2,2,2-trifluoroethyl)-3,4,5,6-tetrafluorobenzoic acids (3) the layers (2D architecture) with dimeric and chain-like synthons C(O)OH…O(HO)C are found. In the crystals of 2-[methoxycarbonyl(difluoromethyl)]-3,4,5,6-tetrafluorobenzoic acid (4) only dimers (0D architecture) form with the chain synthon that incorporates both an ester and a carboxylic group. In the crystals of 1 and 2 intermolecular Н-O…π interactions, in the crystals of 4 C-F…π interactions, and in 3 both types of interactions are observed.

By the reaction of [Mo₃S₄(C₂O₄)₃(H₂O)₃]^2- with PdCl₂ and NH₄H₂PO₂ as a reducing agent, followed by the addition of PPh₃, a new oxalate cuboidal cluster complex [Mo₃(PdPPh₃)S₄(C₂O₄)₃(H₂O)₃]^2- is obtained. It was isolated and structurally characterized as K₂[Mo₃(PdPPh₃)S₄(C₂O₄)₃(H₂O)₃]⋅0.5H₂O.

By the high-temperature reaction of Nb₂S₄Br₄ and TlBr a thallium salt of the anionic cluster complex [Nb₂S₄Br₈]^4- is obtained. Its crystal structure is determined by X-ray structural analysis. The complex is also characterized by Raman spectroscopy and electrospray-mass-spectrometry.

By means of X-ray diffraction the chain structure of [Cu(l-Arg)₂]Hg₂Cl₆ (monoclinic, a = 10.2348(9) Å, b = 9.1386(7) Å, c = 14.8521(14) Å, β = 97.455(11)°, space group P2₁) is established. The chains are formed by square-planar [Cu(l-Arg)₂]²⁺ cations of the type trans-[Cu(N)₂(О)₂] (l-Аrg is the zwitter-ion of arginine; Cu-N 1.992 Å and 1.938(6) Å, Cu-O 1.953 Å and 1.967(4) Å) that are bonded to two adjacent binuclear [Cl₂Hg(μ-Cl)₂HgCl₂]^2- ions through its clorine atoms Cl (Hg-Cl bonds are within 2.34-2.78 Å). With these two additional Cu…Cl contacts Cu adopts the geometry of an elongated octahedron with two apical Cl (Cu-Cl 2.961 Å and 3.064(3) Å).

The X-ray analysis of a single crystal of Mg(C₁₂H₁₃N₄O₄S)₂⋅11H₂O, where (C₁₂H₁₃N₄O₄S)^- is the anion of 4-p-aminobenzenesulfamido-2,6-dimethoxypyrimidine (sulfadimethoxine) is carried out. Unit cell parameters are: а = 19.753(4) Å, b = 34.031(7) Å, c = 13.859(3) Å; β = 125.37(3)°, C2/c, Z = 8, R(F) = 0.042. The structure is built of [Mg(OH₂)₆]²⁺, (C₁₂H₁₃N₄O₄S)^-, and water molecules and corresponds to the formula [Mg(OH₂)₆](C₁₂H₁₃N₄O₄S)₂⋅5H₂O. The IR bands of ν_asymSO₂ and ν_symSO₂ are bathochromically shifted as a result of their participation in hydrogen bonding, and not because of any direct coordination of sulfadimethoxinate anion to the complexing atom through oxygen.

The structure of the syn-isomer of 2-N,N′-dimethylamino-5-methylbenzophenone oxime is studied by X-ray diffraction and mass-spectrometry. This molecular compound crystallizes in the triclinic system. Unit cell parameters are: a = 19.5318(10) Å, с = 19.5439(17) Å, V = 6456.9(7) ų, Z = 18, space group The molecules are linked into centrosymmetric pseudo dimers by hydrogen bonds О-H…N formed by the oxime groups. The pathway of the electron-impact induced decomposition of the compound is discussed.

An X-ray diffraction analysis and quantum chemical calculations of hydrated 2-thenoyltrifluoroacetone show that the planar diketone, form of ТТА found in its metal complexes, does not occur in the free ligand. Hydrated ТТА with two geminal hydroxo groups has a non-planar structure stabilized by an intramolecular hydrogen bond.

X-ray structure of 6,11-dihydro-6,11-methano-5H-benzo[5,6]cyclohepta[1,2-b]pyridinol-11 is determined.

Two benzodiazepine derivatives, C₂₃H₂₂N₂O (I), 2-methyl-8-methoxy-2,4-diphenyl-2,3-dihydro-1H-1,5-benzodiazepine, and C₂₂H₁₇N₃O₂Br₂ (II), 2-methyl-7-nitro-2,4-bis(4′-bromophenyl)-2,3-dihydro-1H-1,5-benzodiazepine, were studied by single crystal X-ray diffraction method. Compound (I) crystallizes in the monoclinic system, space group P2₁/c, a = 13.1703(17), b = 11.1990(14), c = 12.9093(16) Å, β = 107.831(2)°, V = 1812.6(3) ų, Z = 4. Compound (II) crystallizes in the monoclinic system, space group P2₁/n, a = 11.7345(12), b = 12.7477(13), c = 13.5965(14) Å, β = 95.221(2)°, V = 2025.4(4) ų, Z = 4. The molecules of (I) and (II) have T-shape form with the diazepine ring at the junction point. The seven membered central benzodiazepine ring in both structures adopt a twist-boat conformation. The crystal packing is stabilized by C-H…π (in I) and C-H…O (in II) interactions.

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.

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.

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 Н-associate; and stable triclinic, in which four molecules of the unit cell organize an Н-complex in the form of a cyclic tetramer. It is found that crystalline samples of 3- and 4-biphenylmethanols consist of chain Н-associates. A glass-like sample of 2BPhM being a mixture of Н-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 Н-associates and free molecules are realized.

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.

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.

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.

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.

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.

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.

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.

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.

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, а(II) = 9.3371(5) Å; V(I) = 835.50(5) ų, V(II) = 814.02(8) ų; 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.

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, d_x = 1.701 g/cm³. The distance Pb-Cu in the dimer is 3.68 Å.

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/с, 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) ų, Z = 8, d_calc = 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)^…π^…H(C), π-delocalized system of Ph rings of the anions, and interaction of ions with ethanol molecules N-H^…O-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.

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.

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.

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 Н-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 О-H, С=О, С≡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.

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.

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.

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.

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, d_calc = 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 (2О+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-Сu-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)°.

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/с; 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) ų, Z = 2, d_calc = 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 I_hkl ≥ 2σ_I of 23,655 reflections collected and 5618 independent I_hkl (Bruker X8 APEX diffractometer, λMoK_α).

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.

The crystal structure of [Cu^II(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, d_calc = 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.