Vol 64, No 5 (2019)

In the present study, we report the structure of one new phosphoramidate counter ion. The single crystal X-ray diffraction analysis revealed that C₁₈H₁₈N₃O₄P₁, consists of a discrete [C₁₈H₁₈N₂OP]⁺ cation and NO₃⁻ anion. The compound crystallizes in triclinic system, space group P-1, unit cell a = 9.4935 Å, b = 10.4556(4) Å, c = 11.1560(3) Å, α = 63.951(3)°, β = 67.039(3)°, γ = 66.017(3)°. The interaction between cation and anion has occurred through hydrogen bonding. The strength of different hydrogen bonds between two counter ions was studied by DFT calculations in the gas phase. We optimized the hydrogen atoms and kept all other atoms invariant in the optimization process. The H-optimized systems included one nitrate anion and one phosphoramide cation which were connected by special intermolecular interactions. The binding energies of these interactions were calculated (M062X/6-311G*) and corrected for the basis set superposition error (BSSE) using by counterpoise (CP) procedure. Moreover, the main noncovalent inter-molecular interactions were studied by Hirshfeld surface analysis and finger print plots.

The effect of the indium dopant on the magnetic properties and crystal structure of M-type barium hexaferrite was studied. Relying on Mössbauer spectroscopy data and magnetic measurements, the distribution of the dopant ions in the sublattices and their effect on magnetic characteristics were established. The dependences of specific magnetization and coercivity on the location of indium ions in the hexaferrite crystal structure and on the indium ion content were determined. Weakening of the exchange interaction between the sublattices at the replacement factor x = 0.6 and change in the magnetic moment orientation determined by the angle θ were revealed.

The structural features of 24 mononuclear octahedral monooxo d²-Re(V) complexes with single charged oxygen atoms of bidentate chelate (O, N) ligands (Lⁿ) of the general formula [ReO(Lⁿ)₂(L_mono)] (where L_mono is a monodentate ligand) containing six-membered chelate rings ReNC₃O are discussed. The O(Lⁿ) atoms, with three exception, are in the trans positions to the O(oxo) ligands. In the two complexes, the oxygen atoms of the acido-ligand OMe⁻ occupy the trans positions to the oxo ligands, and in the third, it is occupied by the O atom of the neutral H₂O ligand. In the case of complexes [ReO(Lⁿ)₂(L_mono)] with five-membered chelate cycles ReNC₂O, the structures of three complexes with L_mono ligands in the trans positions to oxo ligands are also known: one with L_mono = Cl⁻ and two with L_mono = OMe⁻.

The reactions of tris(p-tolyl)antimony, tris(3-fluorophenyl)antimony, and tris(4-fluorophenyl)antimony with 2-hydroxybenzaldoxime at equimolar amounts in diethyl ether in the presence of hydrogen peroxide have been studied. It has been established that 2-hydroxybenzaldoxime reacts as a bifunctional compound, and the simultaneous oxidation and dearylation of triarylantimony is observed. The products of these reactions are bis(μ₃-2-oxybenzaldoximato-O, O′, N)-(μ₂-oxo)-tetrakis(p-tolyl)-diantimony (I), -tetrakis(3-fluorophenyl)diantimony (II), and -tetrakis(4-fluorophenyl)diantimony (III), in which two structurally equivalent antimony atoms linked via two tridentate bridging ligands and an oxygen atom have a distorted octahedral coordination with the C₂O₃N surrounding according to X-ray diffraction study data. Their molecules have three types of Sb–O distances with the bridging oxygen atom (1.942(5), 1.946(5) Å in IA and IB, respectively, 1.948(3), 1.953(2) Å in II, and 1.954(3), 1.958(3) Å in III), the oxygen atoms of oxime groups (2.087(7) Å in IA and IB, 2.076(2), 2.097(2) Å in II, and 2.094(3), 2.081(3) Å in III), and the oxygen atoms of hydroxy groups (2.022(7), 2.024(7) Å in IA and IB, respectively, 2.002(3), 2.010(3) Å in II, and 2.015(4), 2.019(3) Å in III) and Sb⋯N coordination bonds (2.236(8), 2.238(9) Å in IA and IB, respectively, 2.256(3), 2.230(3) Å in II, and 2.266(4), 2.251(4) Å in III).

The structures, energies, and spectroscopic characteristics of the \({\rm{A}}{{\rm{l}}_{13}}({\rm{B}}{{\rm{H}}_3})_n^-\) and \({\rm{A}}{{\rm{l}}_{13}}({\rm{Al}}{{\rm{H}}_3})_n^-\) complexes with the centered icosahedral aluminum cluster \({\rm{Al}}_{13}^-\) successively “solvated” with borane and alane molecules with n = 1–16 sequentially “solvated” with borane, alane, diborane, and dialane molecules (L = BH₃, AlH₃, B₂H₆, and Al₂H₆) have been calculated by the density functional theory (DFT) method. According to calculations, in the first half of the borane series \({\rm{A}}{{\rm{l}}_{13}}({\rm{B}}{{\rm{H}}_3})_n^-\), the BH₃ molecules are coordinated to edges of the Al₁₃ cage through two B–Al bonds and the B–H_b–Al hydrogen bridge. With increasing number of ligands n, B–H_b–B′ bridges between the ligands and binuclear B₂H_m moieties with m = 3–5 appear in the surface region of the complexes. The calculations predicted the stability of borane complexes to decomposition with elimination of a diborane molecule and the possibility of their existence in the isolated state. In the early members of the alane series \({\rm{A}}{{\rm{l}}_{13}}({\rm{Al}}{{\rm{H}}_3})_n^-\), the ligands are also bound to the cage through two Al–Al′ bonds and a hydrogen bridge; with increasing n, they are even more prone than boranes to form H-bridges between the ligands and binuclear surface moieties Al₂H_m. At n > 10, the internal cage is severely distorted and opened. At the end of the series, the cage changes its composition due to transfer of several Al atoms to the surface region. The alane complexes are less stable than their borane analogues; however, for the systems of the second half of the \({\rm{A}}{{\rm{l}}_{13}}({\rm{Al}}{{\rm{H}}_3})_n^-\) series, the calculations predict noticeable stability to decomposition with elimination of the dialane molecule. Trends in structural characteristics and energies of the complexes with increasing n are traced. The results can be of interest for modeling the structure and stability of more complicated nanosized aluminoborohydrides and aluminohydrides with high hydrogen content.

The geometries of (6666)macrotetracyclic Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II) complexes with the NNNN coordination of the chelant donor sites, that can form through “self-assembling” in the MCl2–2-aminobenzenecarbaldehyde binary systems have been calculated by the DFT OPBE/TZVP method with the Gaussian 09 program package. The bond lengths and angles and nonbonded angles in these complexes with the MN₄ chelate core have been determined. It has been demonstrated that neither the metal chelate core nor the six-membered chelate rings are strictly planar, although all the rings are identical or nearly identical to each other by the sets of bond angles. The noncoplanarity of the chelate rings is not pronounced (the deviation of the sum of the interior angles in each of them does not exceed 15°), the bond angles between the M–Cl bonds are 180°.

The literature data on thermal behavior of crystalline nickel fluorides NiF₃ and Ni₂F₅ in the higher oxidation states are analyzed. Their enthalpies of formation are calculated: Δ_fH^o(Ni[NiF₆](cr), 0 K) = -1399.6 ± 6 and Δ_fH^o(Ni₂F₅(cr), 0 K) = −1370.5 ± 8 kJ/mol. The partial saturated vapor pressures in the NiF₃–Ni₂F₅ and Ni₂F₅–NiF₂ systems over a broad temperature range are determined. The technical impossibility to achieve a measurable pressure of NiF₃ is shown. The findings are compared to the data for similar derivatives of 3d-block elements and ruthenium and platinum trifluorides. Ni₂F₅(cr) is suggested to be used as a fluorine accumulator.

By the example of olivine gabbronorite, a basic plutonic rock of the gabbroid family, the effect of temperature and the redox properties of the crystallization atmosphere on the equilibrium composition of the formed phases was studied by physicochemical modeling. Brief data were presented on the chemical composition of the rock-forming minerals and their effect on the properties of the rock. Specific features of heating, melting, and crystallization of olivine gabbronorite were considered with taking into account the external conditions and the mutual influence of the minerals. The possibility of modifying the chemical and mineral compositions of olivine gabbronorite was shown. Recommendations were given on choosing a method for modifying the initial composition of olivine gabbronorite.

Solubilities, densities, and refractive indices for the ternary system (K₂B₄O₇ + Mg₂B₆O₁₁ + H₂O) at 298.15 K have obtained using the method of isothermal dissolution equilibrium. On the basis of the experimental data, the phase diagram and its corresponding physicochemical properties versus composition diagram in the system have been plotted. It has been found that there is one eutectic point and two crystallization regions corresponding to the large area of inderite (L + Mg₂B₆O₁₁ · 15H₂O) and the relative small area of potassium borate tetrahydrate (L + K₂B₄O₇ · 4H₂O), respectively. Neither double salt nor solid solution have been found in this system. The physicochemical properties (density and refractive index) of the ternary system at 298.15 K change regularly with the increasing of potassium borate concentration. The calculated values of density and refractive index using empirical equations of the ternary system are in good agreement with the experimental values.

Extraction of rare earth elements (REE) in 1,1,7-trihydrododecafluoroheptanol–water system with phosphoryl podands derived from diphosphonic acids of general formula 2-[(HO)(EtO)(O)P]-4-Et–C₆H₃–(OCH₂CH₂)_n–OC₆H₃-4-Et-2-[P(O)(OEt)(OH)], n = 1–5 has been studied. Effect of medium acidity on REE extraction efficiency and selectivity has been studied. Crystal structure of 1,5-bis[2-(oxyethoxyphosphoryl)phenoxy]-3-oxapentane has been established by X-ray diffraction.

The manufacture of LiNbO₃ and LiNbO₃:Zn fine-grained powders by two variants of the sol–gel process was studied. The microstructure, mechanical and electric properties of LiNbO₃ and LiNbO₃:Zn ceramics prepared from powders of various origins were studied. The ceramics prepared from powders that had been fractionated by elutriation had uniform micro- and submicrostructure, improved strength characteristics, and ionic grain-boundary conductivity. Doping LiNbO₃ with Zn²⁺ reduced the electronic conductivity of LiNbO₃:Zn ceramics, and this allowed the ceramics to be efficiently polarized and their piezoelectric properties to be improved.