Vol 59, No 2 (2018)

The ab initio projector augmented wave (PAW) method is used to calculate the electronic structure of Li-doped cadmium oxide with NaCl structure. The preference energy for Li atoms in interstitial sites and the energy of impurity oxidation are calculated. Interstitial positions for Li atoms are shown to be stable under thermodynamic equilibrium, but Li atoms can substitute Cd atoms in presence of vacancies in the oxygen sublattice. We consider the following complexes: one Li atom in the interstitial site and the other Li atom in Cd position; one Li atom in Cd position and one oxygen vacancy; a pair of oxygen vacancies; and show that these complexes are formed to have the shortest possible distance between their components. The band gap substantially decreases when Li atoms occupy interstitial sites to explain considerable increase of experimental conductivity.

A new method is proposed to calculate energy levels and wave functions of vibrational-rotational molecular states without the necessity to separate the types of motion. The procedure is described to find the corresponding energy matrix which is diagonalized to obtain the final solution. The simplicity of computing matrix elements makes it possible to analyze very large molecules.

A theoretical study of hydrotreatment of the oxolane molecule without a catalyst and in the presence of a catalyst is performed by numerical DFT/B3LYP methods with 6-31G(d) and LanL2DZ basis sets. The catalyst used in this study is tungsten disulfide (WS2) which is modeled by a three anionic vacancy site WS₃H⁺₃. Hydrogenolysis of the oxolane molecule under hydrogen pressure is simulated through two sequential stages. The temperature and pressure experimental conditions taken in account in the study were 523 K, 573 K, and 623 K under 40 bar. The analysis of variations of diverse system parameters during the process reveals that oxolane undergoes a C–O bonds cleavage at a ring opening at the end of both hydrogenolysis processes. The first hydrogenolysis process leads to the formation of a butan-1-ol molecule, which then undergoes second hydrogenolysis under the same pressure and temperature conditions. Finally, second hydrogenolysis produces water and butane molecules.

¹H and ¹⁹F NMR, XRD, and DTA methods are used to study thermal properties, ion mobility, and phase transitions (PT) in solid solutions obtained by doping anion-cationic conductor (NH₄)₂ZrF₆ with indium trifluoride. The types of ionic mobility are determined in the fluorine and ammonium sublattices of synthesized solid solutions at 150–450 K, their activation energies are estimated. A phase transition associated with formation of high-temperature modifications is registered at 400–413 K; ionic mobility in these modifications is mostly due to the diffusion of fluorine and ammonium ions.

The O–H stretching vibrations of hydrogen-bonded glass formers (ethanol and glycerol) are studied by Raman scattering in a temperature range where the liquid state changes from low-viscous to solid. Several characteristic bands exhibiting different temperature behavior can be distinguished in the O–H vibrational spectrum of ethanol. The appearance of an additional band on cooling ethanol below 220 K is related to the appearance of locally favored structures. No notable manifestations of these features are detected in the spectra of glycerol.

Several new 4-acetamidoalkyl pyrazoles are synthesized by an efficient, one-pot three-component reaction of 3,5-dimethyl-1-phenyl-1H-pyrazole or 3-methyl-1-phenyl-1H-pyrazol-5-ol, aromatic aldehydes, and acetonitrile in the presence of chlorosulfonic acid at room temperature. The products are characterized based on IR, ¹H and ¹³C NMR data and evaluated as potential COX-2 and B-Raf inhibitors by molecular docking studies. All the products showed the potency of B-Raf and COX-2 inhibitory effects with a greater binding affinity to B-Raf than COX-2 protein.

Aqueous solutions of natural osmolytes (trimethylaminoxide (TMAO), urea, and their mixture) at relatively small (biologically relevant) concentrations are analyzed by the all-atom molecular dynamics simulation. In the recent work (Smolin N. et al. PCCP. 2017. 19. P. 6345) it has been noted that in the protein hydration shell the fraction of TMAO molecules is much smaller than that of urea. The urea addition causes a further decrease in the TMAO fraction in the protein hydration shell. This work shows that in binary solutions urea fraction at urea molecules is always larger than the bulk urea concentration. At the same time, the TMAO fraction near TMAO is the same as in the bulk. In ternary solutions, TMAO and urea behave the same as the binary ones, i.e. they do not noticeably affect each other. This means that the behavior of TMAO and urea molecules in the protein hydration shell is associated with protein rather than their interaction with each other.

The crystallographic analysis of the garnet structure type (Al₂Ca₃(SiO₄)₃, Ia3d symmetry) establishes the determining role of the [AlCa₆Si₆] cation group with the local symmetry \(\bar 3\) in the structure formation. The glide planes of three directions coherently assemble these groups. High structural stability (three not symmetry-fixed coordinates per 80 atoms, the fundamental volume V*~17 ų) promotes the occurrence of various atomic compositions in it. The relation with the β-W structure type and the structure of menezesite mineral is shown.

The crystal structures are determined for KDy[AlSi₄O₁₂]·0.41H₂O and KTb[AlSi₄O₁₂]·0.32 H₂O compounds synthesized under hydrothermal conditions, which crystallize in the space group C2/c with the unit cell parameters a = 26.6956(6) Å and 26.619(1) Å, b = 7.2477(2) Å and 7.2553(3) Å, c = 14.7705 Å and 14.8200(6) Å, β = 123.7721° and 123.5149° for KDy and KTb aluminosilicates respectively. Tetrahedral layers in the structures of the studied crystals differ in their packing order and can be matched in space with a twofold rotational symmetry axis. In the studied phases Dy and Tb present in a trivalent form.

Three new Cu(I) π-complexes with 2,5-bis(allylthio)-1,3,4-thiadizole (Bialtia) ([Cu₃Cl₃(Bialtia)₂] (1), [Cu₃Cl₃(Bialtia)] (2), and [Cu₂Cl₂(Bialtia)] (3)) are obtained by the alternating current electrochemical synthesis and studied by single crystal X-ray diffraction. A distinctive feature of Bialtia is its ability to coordinate to Cu(I) atoms by nitrogen atoms of the thiadiazole core and two allyl groups. The formation of island inorganic {Cu₃Cl₃} moieties occurs in 1 through π coordination of two independent Bialtia molecules by three metal atoms. Due to the absence of one Bialtia molecule in 2, inorganic {–Cu₃Cl₃–} subunits join into infinite chains {[Cu₃Cl₃(Bialtia)]}_n}. The structure of [Cu₂Cl₂(Bialtia)] (3) contains two Cu(I) atoms with different coordination environments: distorted tetrahedral and trigonal.

Three Co(II) complexes [Co(meophtpy)₂](ClO₄)₂·2CH₃CN (1), [Co(nh₂phtpy)₂](ClO₄)₂·2CH₃CN (2), [Co(ftpy)₂](ClO₄)₂·2CH₃CN (3) and three Mn(II) complexes [Mn(nme₂phtpy)₂]·(ClO₄)₂·2CH₃CN (4), [Mn(ftpy)₂](ClO₄)₂·CH₃CN (5), [Mn(meophtpy)(H₂O)(NO₃)₂]·CH₃CN (6) (meophtpy, 4′-(4- methoxyphenyl)-2,2′:6′,2″-terpyridine; nh2phtpy, 4′-(4-aminophenyl)-2,2′:6′,2″-terpyridine; ftpy, 4′-(furan- 2-yl)-2,2′:6′,2″-terpyridine; nme₂phtpy, 4′-(4-(N,N-dimethylamino)phenyl)-2,2′:6′,2″-terpyridine) are synthesized and their structures are determined by single crystal X-ray diffraction. Crystal data for 1 are: monoclinic, space group C2/c, a = 14.4781(5) Å, b = 16.2221(7) Å, c = 21.3617(9) Å, and Z = 4. For 2: monoclinic, space group C2/c, a = 14.554(6) Å, b = 15.239(6) Å, c = 21.754(9) Å, and Z = 4. For 3: monoclinic, space group C2/c, a = 14.5285(16) Å, b = 15.3234(16) Å, c = 21.154(2) Å, and Z = 4. For 4: triclinic, space group P-1, a = 12.132(5) Å, b = 12.536(5) Å, c =17.840(10) Å, and Z = 2. For 5: triclinic, space group P-1, a = 9.993(10) Å, b = 13.950(13) Å, c = 15.511(15) Å, and Z = 2. For 6: monoclinic, space group Pc, a = 12.402(7) Å, b = 12.919(8) Å, c = 7.893(5) Å, and Z = 2. In complexes 1–5, Co(II) or Mn(II) ions are coordinated by six N atoms from two terpyridine moieties. In complex 6 the Mn(II) atom coordinates only one terpyridine ligand. All these complexes are linked by hydrogen bonds and face-to-face π–π interactions into three-dimensional networks. In complexes 4–6 the available solvent areas imply their potential applications in gas adsorption or catalysis.

Crystal structures of solvated highly nonplanar nickel(II) and copper(II) complexes of 2,3,5,10,12,13,15,20- octaphenylporphyrin are determined by single crystal XRD analysis. The macrocycles in these systems exhibit mainly ruffled and saddled conformations. The average displacement of the pyrrole carbon atom ΔC_b from the mean plane of the porphyrin ring is as high as ±0.70 Å. The Hirshfeld surface analysis of both structures reveals mainly H…H (57-59%) intermolecular short contacts with a smaller contribution from C…H (16-22%) and H…Cl (11-19%) interactions. The present work suggests that the nonplanarity of the macrocycle in NiTPP(Ph)₄ is largely due to the core Ni(II) ion and less influenced by intermolecular interactions/crystal packing forces, whereas the opposite is true in the case of the nonplanar CuTPP(Ph)₄ structure.

A novel chain polymer based on cluster [Re₄S₄(CN)₁₂]^4– anion and Nd³⁺ cations is obtained by the hydrothermal synthesis. The structure of compound {[Nd(phen)₂(H₂O)Nd(phen)(H₂O)₃(μ-OH)₂][Re₄S₄(CN)₁₂]}·0.5phen·3.5H₂O (1) is determined by single crystal X-ray diffraction. The compound crystallizes in the space group Pī with the cell parameters a = 12.8818(5) Å, b = 14.1219(5) Å, c = 22.0347(9) Å, α = 98.168(2)°, β = 93.518(2)°, γ = 95.734(2)°, V = 3936.3(3) ų.

The crystal and molecular structure of four indolin-2-ones with a bulky phenol substituent is studied by single crystal X-ray diffraction. All structures contain a sterically loaded 4-hydroxy-3,5-di-tert-butylbenzyl substituent at the N(1) position of the indole heterocycle. The crystal unit cells of two compounds with the thiosemicarbazone substituent at the C(3) atom of the cycle include one DMSO solvent molecule and the cells of two other molecules with the oxygen atom at the same position do not include solvent molecules. In two of the studied structures the thiosemicarbazone moiety has the Z,E,E configuration favorable for manifestation of the biological activity of these compounds. In three of four molecules the OH group of the bulky substituent at the N(1) atom of the cycle is not involved in hydrogen bonds due to steric hindrances.

A new approach is proposed to study and describe molecular packings in crystals with the use of atom-atom potentials. The approach is applied to the problem of revealing stable intermolecular contacts and molecular agglomerates for two crystal structures previously investigated by single crystal X-ray diffraction.

Lanthana-doped zirconium oxide may strongly influence the solid state reaction. A series of samples denoted Zr_xLa_1–x (where x = atomic percentage of the element) are prepared by hydrolysis in the neutral medium from ZrO₂ and La₂O₃. These samples are calcined under air at 450 °C, 900 °C, and 1200 °C, then characterized by specific surface area (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermoreductions programmed under H₂ (TPR–H₂). The results show that after calcination at 450 °C, the lanthanum addition increases slightly the zirconia surface area and the XRD analysis does not reveal any interaction between two oxides. After calcination at 900 °C, sintering appears and oxides lose half of their surface area. Lanthanum is not inserted into the structure of ZrO₂, while some interaction occurs between lanthanum and zirconium oxide. At 1200 °C, the sintering of the samples is very important; the specific surface is about 1 m²/g^–1; XRD results show that Zr_xLa_1–x are formed basically by three mixed oxides: La₂Zr₂O₇, La_0.5Zr_0.5O_1.75, La_0.46Zr_0.54O_1.77, which is confirmed by the SEM method. H₂-TPR experiments confirm that changes in the reducibility can reflect some alterations of the nature of interactions between ZrO₂ and La₂O₃. Preliminary experiments on zirconia do not reveal the occurrence of significant reduction processes. On the other hand, extensive reduction of La₂O₃ is much more accentuated for lanthana samples. At high temperatures, a significant lessening in the H₂ consumption suggests that ZrO₂ would likely interact with La₂O₃, which is confirmed in the results indicating the presence of the pyrochlore type of oxides mentioned above.

Three new metal-organic frameworks [Zn(Hibdc)₂]·DMF (1), (H₂NMe₂)[Li₂Zn₃(H₂O)(dmf)(Hbtc)₃(btc)]·6DMF·H₂O (2), and [Li₂Zn₂(H₂O)₂(bpp)(bpdc)₃]·7DMF (3) are obtained in the interaction of heterometallic carboxylate complex [Li₂Zn₂(piv)₆(py)₂] with isophthalic (H₂ibdc) and trimesic (H₃btc) acids and in the presence of both 4,4′-biphenyldicarboxylic acid (H₂bpdc) and 4,4′-bispyridylpropane (bpp). The structure of the obtained compounds is determined by the single crystal X-ray diffraction analysis. In the reactions studied the structure of the initial {Li₂Zn₂} fragment is not retained. A complicated fragmentation of this four-nuclear block occurs, including the formation of binuclear heterometallic dimers {LiZn}.

Hydrazone [HydrHSal]∙Н₂О is synthesized for the first time by the interaction of 2-(7-bromo-2-oxo-5- phenyl-3H-1,4-benzdiazepin-1-yl)acetohydrazide (gidazepam) with salicylic aldehyde and characterized by the elemental analysis, thermogravimetry, mass, electron, IR, and NMR spectroscopic techniques. The molecular and crystal structure is determined by single crystal X-ray diffraction.

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