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The electronic structure of anthracene, its dimer, and intermediate structures composed of two anthracene molecules were calculated in the density functional theory. The calculated potential barrier to anthracene dimerization is ~55 kcal/mol; the dissociation barrier is ~45 kcal/mol. The pressure required for the reaction to reach the transition state and acting on the anthracene crystal is ~60 kbar. Lower pressures, ~10 kbar, are required for molecules to approach each other to distances of ~3 Å, at which tunnel dimerization is possible for photoexcited molecules.

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 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.

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 О atoms. The "honeycombs" are additionally linked by their Ва atoms with the О 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 Ва atoms is 10 (one water molecule; five О atoms of the complex anions, one from each of the nearest neighbors; and four О atoms of the hydrocarbonate ions).