Intermetallic Compounds KnMm (М = Ag,Au, As,Sb, Bi,Ge, Sn,Pb): Geometrical and Topological Analysis,Cluster Precursors,and Self-Assembly of Crystal Structures

Crystallography Reports - A geometrical and topological analysis and simulation of the self-assembly of the crystal structures of intermetallic compounds formed in the K–M (M = Ag, Au, As,...     

Synthesis,characterization, and mesomorphic investigation of vinyl ester-substituted chalcones and effect of lateral ‒NO2 and ‒OCH3 group

A novel homologous series of α-4-(4′-n-alkoxy cinnamoyloxy) phenyl β-2″-nitro, 3″–4″ di methoxy benzoyl ethylenes, H_2n+1CnO?C₆H₄?CH?CH?COO?C₆H₄?CO?CH?CH?C₆H₂(NO₂) (OCH₃)₂ (n = 1–8, 10, 12, 14, 16, 18) has been synthesized. All these compounds have been characterized by suitable spectroscopic techniques. C₁ homologue is nonmesogenic, while C₂ homologue shows enantiotropic nematogenic property and the rest of the homologous (C₃?C₁₈) displayed enantiotropically smectogenic plus nematogenic phase. Phase transition temperatures and textures of the LC phase were determined by an optical polarizing microscopy (POM) equipped with a heating stage. The mesomorphic properties of these compounds were confirmed by differential scanning calorimetry (DSC) analysis.     

Synthesis,structure, spectroscopic investigations,and computational studies of optically pure β-ketoamide

Chemical preparation, X-ray single crystal diffraction, IR and NMR spectroscopic investigations of a novel nonlinear optical organic compound (C₁₇H₂₂NO₂Cl) are described. The compound crystallizes in the orthorhombic system with the non-centrosymmetric sp. gr. P2₁2₁2₁. In the crystal structure, molecules are interconnected by N–H…O hydrogen bonds forming infinite chains along a axis. The Hirshfeld surface and associated fingerprint plots of the compound are presented to explore the nature of intermolecular interactions and their relative contributions in building the solid-state architecture. The molecular HOMO–LUMO compositions and their respective energy gaps are also drawn to explain the activity of the compound. The first hyperpolarizability β_tot of the title compound is determined using DFT calculations. The optical properties are also investigated by UV–Vis absorption spectrum.     

Crystal and molecular structure determination, TGA, DTA, and infrared and Raman spectra of rubidium nitroprusside monohydrate, Rb2[Fe(CN)5NO]·H2O

The crystal structure of rubidium nitroprusside monohydrate, Rb₂[Fe(CN)₅NO] · H₂O, has been determined from X-ray diffraction data and refined using direct and Fourier methods to R = 0.066 and Rw = 0.075, employing 1894 independent reflections with I > 3 (I). The substance crystallizes in the monoclinic space group C2/c (C ⁶ _2h), with a = 13.987(2), b = 10.241(1), c = 18.151(1) Å, = 110.94°, and Z = 8. Anions are located at C ₁ sites, one per asymmetric unit, and are slightly distorted octahedra. TGA, DTA, FTIR, and FTIR Raman results were interpreted on the basis of the formula of the compound, its crystal structure, and the behavior of other nitroprussides.     

Di-μ-sulphido-bis[4-methyl-piperidinedithiocarbamate tin(IV)]: Synthesis,characterization, and crystal and molecular structure

The title compound, C₁₅H₂₆SnN₂S₅Cl₂, was prepared, and characterized by means of X-ray and IR measurements. The crystals are monoclinic, space groupP2₁/n, (non standard setting ofP2₁/c, No. 14) witha=12.330(2),b=11.930(1),c=17.055(2) Å,=106.21(1)° andZ=4.The structure was solved by the heavy-atom method, and least-squares refinement of the structural parameters led to a conventionalR factor of 0.028 for 1284 independent reflections. The structure consists of discrete dimeric units with the metal coordinated to six sulphur atoms. The IR spectrum is consistent with the presence of the sulphur bridge atoms between the two metal ions.     

Synthesis, X-ray and neutron diffraction and Mössbauer studies of SrFeOx crystals

Tetragonal single crystals of the nonstoichiometric strontium ferrate with the lattice parameters a = 3.8525(3) and c = 3.8781 (3) Å have been synthesized for the first time by the method of floating-zone melting in the SrFeO_x system. The neutron diffraction patterns of the crystals showed weak additional reflections indicating the formation of the superstructure with double spacing along the [hh0] direction. The Mössbauer spectra of the crystals were obtained and measured in the temperature range 80–300 K. It was established that below the temperature T _N = 232(1) K, the crystals are in the magnetically ordered state with 3/5 of iron ions being in the trivalent state and all the remaining iron ions in the tetravalent state. This leads to the crystal composition SrFeO_2.71. The electric resistivity of the crystals equal to 100 ω cm at room temperature drastically decreases at temperatures exceeding 470 K.     

Synthesis,Crystal Structure,Antioxidant, and α-Glucosidase Inhibitory Activities of Methoxy-substituted Benzohydrazide Derivatives

Eight methoxy substituted at the benzylidene moiety benzohydrazide derivatives [R = 2-OCH₃ (1), 3-OCH₃ (2), 4-OCH₃ (3), 2,3-(OCH₃)₂ (4), 3,4-(OCH₃)₂ (5), 2,4,5-(OCH₃)₃ (6), 2,4,6-(OCH₃)₃ (7), and 3,4,5-(OCH₃)₃ (8)] were synthesized and characterized by ¹H NMR, FT-IR and UV-Vis spectroscopy. The crystal structure of 4 was determined by single crystal X-ray diffraction (sp. gr. Pbca, Z = 8). The molecule is slightly twisted with the dihedral angle between the two phenyl rings being 9.33(14)°. The methoxy group at the ortho position is twisted [C–O–C–C angle is–109.2(3)°] whereas the other at meta position is co-planar with the attached benzene ring. In the crystal packing, the molecules are linked into two-dimensional network parallel to the (001) plane by O–H···O, O–H···N, and N–H···O hydrogen bonds. Compounds 1–8 were evaluated for an antioxidant and α-glucosidase inhibitory activities and the results suggested that the ?OCH₃ substituent was ineffective for bioactivity enhancement.     

Synthesis of Sulfonated Cholesterol Derivatives—Electrical,Thermal, and Optical Properties

Poly(cholesterylacrylatesulfone) (PCHAS) and poly(cholesterylacrylatesulfone-co-1-hexene)s (PCHASHs) at different ratios are synthesized from the monomer cholesteryl acrylate. The liquid crystalline phases are observed under a hot stage fitted with a polarizing optical microscope. The polysulfone and copolysulfones are characterized by FT-IR, ¹H-NMR, DSC, and TGA techniques. From SEM (EDX) the qualitative amounts of elemental sulfur found in PCHAS and PCHASH11 are 2.90 weights (%) and 4.39 weights (%), respectively. The GPC data using THF as the solvent shows that the number average molecular weight of the PCHAS is 5268 g/mol and the molecular weights of the PCHASHs are higher than the PCHAS.     

Synthesis, characterization, and properties of nanoscale titanium dioxide modifications with anatase and η-TiO2 structures

Nanoscale titanium dioxide modifications with anatase and η-TiO₂ structures have been obtained by the sulfate method. Bands characteristic of the η-TiO₂ phase are selected in the Raman and IR spectra of the samples containing this phase. A study of the properties of synthesized samples applying a complex of physicochemical methods revealed that nanocrystals in the samples containing phases of different modifications differ in size, structure, and surface composition. It is shown that the abovementioned nanoscale modifications are characterized by the efficient sorption of As (V), Bi (III), and V (V) from aqueous media; the degree of sorption depends on the size and structural form of nanocrystals.     

Tribological,Physicomechanical, and Other Properties of Composites Based on Ultra-High Molecular-Weight Polyethylene,Polytetrafluoroethylene, and Еthylene–Tetrafluoroethylene Copolymer with Quasicrystalline Filler Al–Cu–Fe

Crystallography Reports - An urgent problem in improving polymer-based tribotechnical materials is to reduce the friction and wear coefficients with preservation of sufficiently high...     

Glass transition and specific heats in the systems PS,PSe,AsS and AsSe

The glass transition temperatures were measured in the systems AsS, As_0.5P_0.5S, PSe, AsSe and PAsSe. Heat capacities of the glasses in the selenium systems were obtained by differential scanning calorimetry. As shown by the residual entropies departures from ideality are high in the chalcogen glasses. The results are discussed in terms of the structure of glasses in these systems. The thermodynamic data of glasses and liquids in these systems indicate a balance of intra- and intermolecular saturation of bonds. The amount of polymerization increases with increasing average molecular weight in the glass and with increasing temperature in some of the investigated liquids.     

Preparation,structural, and spectroscopic study of tetrakis(4-methylpyridinium) β-octamolybdate

The title compound, (C₆H₈N)₄[Mo₈O₂₆], has been prepared and its crystal structure determined by X-ray crystallography. The compound is triclinic,P¯1,Z=1 witha=10.167(1),b=10.745(1),c=10.027(8) Å,=85.05(1),=106.73(3), =107.75(1)°,V=999.1(7) ų,F(000)=748,D _x=2.59 andD _o=2.61(1) Mg/m³. The [Mo₈O₂₆]^4– anion shows slight differences in several bond lengths and angles when compared with other related octamolybdates. The planar cations are connected to the polyanions through bifurcated hydrogen bonds. The MoO₆ octahedra are distorted and the distortion has been evaluated using three different equations. The spectroscopic study shows that the cations are protonated and the polyanion presents the well-known infrared spectrum for octamolybdates.     

Crystal and molecular structure ofN,N′-diphenylpiperazine N,N′-dioxide octahydrate

The title compound isN,N-DiphenylpiperazineN,N-dioxide octahydrate, C₁₆H₃₄N₂O₁₀:M _r=414.46, orthorhombic, space groupPnma (No. 62),a=12.327(2),b=9.804(1),c=17.443(4) Å,V _c=2108.1(5) ų,Z=4. The structure was solved by the direct method and refined toR=0.056 for 3032 observed MoK reflections. In theN,N-dioxide molecule, all atoms except those of the methylene groups lie on a crystallographic mirror plane. The piperazine ring takes the chair form, with two N-O bonds oriented axially in atrans configuration. The crystal structure is characterized by strong hydrogen bonding between the water molecules, as well as between theN-oxide groups and water molecules, giving rise to a three-dimensional network structure composed of edge-sharing four-membered, five-membered, six-membered, and fourteen-membered rings.     

Electronic Properties,Reactivity, Flexibility,Polarity, Thermodynamic Properties,and Dynamic Simulation of a Series of Hybrid Organic–Inorganic Polyoxoselenomolybdate Compounds

Crystallography Reports - A large theoretical study of three hybrid inorganic-organic polyoxoselenomolybdate-based systems (C7H10N)4[Se2Mo5O21]⋅5H2O (1), (C6H8N)4[Se2Mo5O21]⋅7H2O (2)...     

Magnetic state, elastic constants, and longwave static displacements of atoms in γ-FeNi alloys

The experimental results on the concentration and temperature behavior of longwave (both transverse and longitudinal) static displacements of atoms, as well as the data on the elastic constants (derived from neutron and ultrasonic measurements) of γ-FeNi alloys, are reported. The relationship between the alloy magnetic state and the above-mentioned parameters is discussed and these parameters are classified with respect to the premartensitic phenomena and the Invar effect.     

Growth,structural, optical and thermal properties of potential THz material: N,N-dimethylamino-N′-methylstilbazolium 4-styrenesulphonate

N,N-dimethylamino-N′-methylstilbazolium 4-styrenesulphonate (DSSS), was synthesized by metathesization of the N,N-dimethylamino-N′-methylstilbazolium iodide (DASI) salt with sodium 4-styrenesulfonate. The growth of DSSS single crystal was carried out by adopting the slope nucleation coupled slow evaporation method. DSSS crystals with size 4×2×1 mm³ were grown within a period of 15 days. The structure and composition of the crystal were studied by single crystal X-ray diffraction, CHN and nuclear magnetic resonance (NMR) analyses. The FTIR results reveal the existence of the vinyl groups and their corresponding vibrational modes. The melting point and thermal behavior of DSSS were investigated using differential scanning calorimetric (DSC) and thermogravimetric analyses (TGA).     

Reactivity of 6α,7α-epoxyhimachal-2-ene and crystal structures of 2α,3α-dibromocyclopropanehimachal-5,7-diene and 2α,3α-dibromocyclopropane-6α,7α-epoxyhimachalane

We report here the reactivity of 6,7-epoxyhimachal-2-ene with dibromocarbene generated in situ by phase-transfer catalysis. The stereochemistry of products resulting from dibromocyclopropanation has been established by X-ray crystallography. Compound 3 is orthorhombic P2₁2₁2₁ with a = 7.549 (1), b = 8.432 (1), c = 24.469 (1) Å, V = 1559.8 (5) ų, Z = 4 and compound 5 is monoclinic P2₁ with a = 8.779 (1), b = 15.684 (1), c = 12.111 (1) Å, = 91.869 (1)°, V = 1666.7 (4) ų and Z = 4.     

Growth from Solutions,Structure, and Spectral–Luminescent Properties of Crystalline Films of Di-n-hexyl-para-quaterphenyl

Crystallography Reports - The results of studying the growth and structure of crystalline films of para-quaterphenyl derivative with terminal n-hexyl...