Vol 64, No 6 (2019)

Multiferroic BiFe_0.93Mn_0.07O₃ was prepared by ultrasonic spray pyrolysis (USP), high-temperature self-propagating synthesis (SPS), and thermohydrolysis (TH). The synthetic method was shown to impact the sizes, shapes, and mutual arrangement of particles in agglomerates. Magnetic properties were found to depend on the morphology of agglomerates. Ultrasonic spray pyrolysis produced porous spherical particles that had record-breaking values of coercive force.

The electronic structure and the effect of defects on the optical properties of magnesium fluoride are studied by X-ray photoelectron spectroscopy (XPES). A deviation from fluorine stoichiometry in MgF_2−x is shown to give rise to a long-wavelength shift of the absorption edge. The color of a defective magnesium fluoride caused by the absorption in the range 215–300 nm, low mechanical strength, and optical instability are related to the defectiveness of the fluorine sublattice. A way to reduce the defectiveness is to use specific synthetic procedures and dope the material to be vaporized with a fluorine donor.

The structure and phase features of the WO₃−Co₃O₄ compositions prepared by the sol-gel process are studied by X-ray powder diffraction, IR spectroscopy, scanning electron microscopy, thermogravimetry, and by specific surface determination from low-temperature nitrogen adsorption in the temperature range 200–800°C. An appreciable rise is observed in the gas sensitivity of the compositions compared to the constituent oxides. The dependence of the CO and NO₂ sensitivity on the two-phase composition is elucidated, and an explanation is given to the discovered trend. Low-power semiconductor sensors are manufactured, providing the determination of low nitrogen dioxide concentrations (<1 ppm) with good response and recovery times.

The [Ph₃PR]+[Au(CN)₂]⁻ complexes, where R = CH₂C(O)Ph (I), CHCHMe (II), and (CH₂)₄Br (III), have been synthesized by the reaction between potassium dicyanoaurate and organyltriphenylphosphonium chlorides in water and structurally studied. The phosphorus atoms in organyltriphenylphosphonium cations have a distorted tetrahedral coordination: CPC angles, 107.14(13)°–112.29(17)° (I), 107.38(15)°–110.84(16)° (II), 107.5(3)°–112.1(3)° (III), P-C bonds, 1.792(3)–1.828(3) (I), 1.768(4)–1.800(4) (II), 1.787(5)–1.799(5) Å (III). In nearly linear [Au(CN)₂]⁻ anions, the CAuC angles are 179.38(13)° (I), 177.41(18)° (II), and 178.2(3)° (III), and the Au–C distances are 1.967(6)–2.010(4) Å.

New water soluble Ru(II) binary complex [Ru(C₅H₇N₃)(X)(H₂O)₂] with 2-hydrazinopyridine and its ternary complexes with X = dichloride, oxalate, malonate or pyrophosphate ligands have been synthesized. The complexes have been characterized using elemental analyses, mass, IR, and UV-Vis. spectroscopies, cyclic voltammetry, magnetic susceptibility, and thermal analysis. The complexes are diamagnetic and the electronic spectral data showed that peaks are due to low spin octahedral Ru(II) complexes. The optimized structures of the complexes 1–4 indicate distorted octahedral geometry with bond angles around the ruthenium atom ranged from 80.44° to 99.64°. The values of the electronic energies (−635 to −1145 a.u.), the highest occupied molecular orbital energies (−0.181 to 0.073 a.u.) and lowest unoccupied molecular orbital energies (−0.056 to 0.167 a.u.) indicate the stability of the complexes. The complexes are polarized as indicated from the dipole moment values (9.39–14.27 Debye). The complexes have noticeable cytotoxicity with IC₅₀ (µM): 0.011–0.062 (HepG-2), 0.015–0.080 (MCF-7), 0.015–0.116 (HCT-116), and PC-3 (0.034–0.125).

The structure and the molecular formula of Fe(II) 1,2,4-H-triazole complex has been predicted by using Hartree-Fock (HF) and Density Functional Theory (DFT) methods. The distance between the Fe(II) ions and Fe-N bond length show good agreement with experimental measurements at the low-spin state. It has been conducted by using hybrid/basis set functions of B3LYP/6-31G(d), TPSSh/TZVP, and MO6-2x/6-31G(d). The distance between the Fe(II) ions complexes with deprotonated ligands are 3.30–3.75, 3.44–3.74, and 3.46–3.79 Å, respectively, and undeprotonated ligands are 3.41–4.04, 3.49–3.90, and 3.52–4.09 Å. Meanwhile, the Fe-N bond lengths in the complex with the deprotonated ligand are 1.84–2.07, 1.85–2.04, and 1.89–2.11 Å, respectively, while in the complex with undeprotonated ligands they are 1.89–2.20, 1.84–2.12, and 1.96–2.21 Å. The molecular formula of Fe(II)-Htrz complex is ([Fe(Htrz)₂(trz)]⁺)_n which has been obtained by comparing the energy difference between the complex formation with deprotonated ligands being lower than that with undeprotonated complex. The computational results on the hybrid/basis set function of B3LYP/6-31G(d) induces the difference of energy formation of [Fe₂(Htrz)₄(trz)₂]²⁺, [Fe₂(Htrz)₆]⁴⁺, [Fe₄(Htrz)₈(trz)₄]⁴⁺, [Fe₄(Htrz)₁₂]⁸⁺, [Fe₆(Htrz)₁₂(trz)₆]⁶⁺, and [Fe₆(Htrz)₁₈]¹²⁺ complexes to be −5613.38, −3082.67, −11013.19, −147.40, −16101.36, and −6825.09 kJ/mol, respectively.

Structural parameters, energies, and spectroscopic characteristics of two series of layerwise hydrogenated aluminum clusters Al₄₄H_n (n = 27–44) and Al₈₉H_m (m = 15, 24, 39, and 63) have been calculated by the density functional theory method. It has been shown that increasing number of H atoms in both series entails rapid enhancement of structural distortions up to cooperative rearrangements accompanied by a change in the shape and composition of the surface layer and internal core of the cluster. At the end of the first series Al₄₄H_n, several surface atoms migrate to the outer sphere of the cage to form valence-unsaturated “outer-surface” AlH_n and Al₂H_n moieties, which can be active sites at the stages of deeper hydrogenation. Simultaneously, the inner core [Al]₅ disintegrates, and its atoms are introduced into the surface layer. A family of “inverted” Al₄₂H₄₂ isomers with the hollow [Al₄₂] cage has been localized; the isomers contain the endohedral AlH₄ group and “inner” Al-H bonds with their hydrogen end directed to the center of the inner cavity. At the end of the second series, five alanate groups AlH₄ and two Al₃H₂ fragments bonded to the surface through hydrogen bridges are formed in the outer sphere of the \(\rm{Al}_{89}H_{63}^-\) cluster. The results are of interest for DFT modeling of hydrogenation of nanosized aluminum clusters at the molecular level.

Experimental-statistical mathematical models are built for nickel itaconate thermolysis to relate some response functions (carbon, hydrogen, oxygen, and nickel concentrations in the nanocomposite, yield of the nanocomposite, contents of β-nickel and nickel oxide phases, and nanoparticle diameter) to the thermolysis temperature and time. Response surfaces are constructed to illustrate the dependence of the above-listed response functions on the thermolysis temperature and time. These response functions are analyzed to determine the synthetic parameters that would provide the preparation of nanocomposites with tailored characteristics, in particular, with the highest content of the magnetoactive β-nickel phase.

Phase equilibria in the Cu₂Se−SnSe−CuSbSe₂ system were studied by differential thermal and X-ray powder diffraction analyses. Alloys were obtained by alloying of the preliminarily synthesized and identified initial compounds in a vacuum with subsequent annealing at 650 K for 500 h. Characteristic plots describing this system were constructed, namely, the polythermal sections SnSe−Cu₃SbSe₃, Cu₂Se−[A], and CuSbSe₂−[B], where [A] and [B] are the alloys of the compositions (SnSe)_0.5(CuSbSe₂)_0.5 and (Cu₂Se)_0.5(SnSe)_0.5, respectively; the isothermal section of the phase diagram at 300 K; and the projection of the liquidus surface. It was shown that this system is a quasi-ternary section of the quaternary system Cu−Sn−Sn−Se and is characterized by invariant equilibria: a transient one and a eutectic one. Fields of primary crystallization of phases and the types and coordinates of in- and monovariant equilibria were found. Wide regions of solid solutions based on SnSe and CuSbSe₂ were revealed.

The solubility in the pseudo-ternary aqueous systems based on potassium bis(alkylpolyoxyethylene)phosphate (oxyphos B) or alkylbenzyldimethylammonium chloride (catamine AB) and potassium or ammonium thiocyanates used as salting-out agents is studied by the isothermal cross-section method. It is found that thiocyanates exhibit a high salting-out capacity with respect to catamine AB and have much lower salting-out properties with respect to oxyphos B. The regularities of extraction of iron(III), copper(II), cobalt(II), zinc and cadmium ions in the potassium thiocyanate-catamine AB-water system in the presence of sulfuric acid are studied. It is demonstrated that these metals can be concentrated groupwise via the anionexchange mechanism when sulfuric acid content in the system is > 0.75 mol/L.

Interphase distribution of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y between aqueous HCl solutions and solutions of carbamoylmethylphosphine oxides in the presence of binary extractants, quaternary ammonium dinonylnaphthalenesulfonates, has been studied. It has been shown that the efficiency of extraction of rare earth elements(III) (REE) with carbamoylmethylphosphine oxides increases considerably in the presence of binary extractant in organic phase. The stoichiometry of extracted complexes has been determined, effect of cation nature of the binary extractant, organic solvent, structure of carbamoylmethylphosphine oxides, and HCl concentration in aqueous phase on efficiency of REE(III) recovery into organic phase has been considered.