Structure of 5-Allyl-2-hydroxy-3-methoxyazobenzene

Abstract

5-allyl-2-hydroxy-3-methoxyazobenzene was preperad by the reaction of 4-allyl-2-methoxyfenol and benzenediazoniumchloride and crystallized from dimethylsulphoxide to yield crystals suitable for analysis. The molecular structure was identified by UV-VIS, IR, ¹H-NMR, ¹³C-NMR and elemental analysis. The crystal structure of the title compound was determined as monoclinic by by single crystal X-Ray diffraction technique. The crystal parameters of this compound are as follows: monoclinic P 2 1/n, a=5.559(2) Å,b=14.900(2) Å, c= 17.573(29 Å, P = 98.58(1)?, V = 1439.3(2) ų, Z = 2, Dx = 0.610 g/cm³, F(OOO) = 284, λ (MoKα) = 0.71070 Å, μ = 0.041 mm^?1. The structure was solved by SHELXS-86 and refined by SHELXL-93. R = 0.09 for 1107 observed reflections with I > 2σ (I).     

Structure of 4,4′-butane-(1,4,7-three-p-tolylsulphonyl-1,4,7-three amine) diphthalonitrile

Abstract

The crystal structure of the title compound, C₄₁ H₃₅ N₇ O₆ S₃ was determined as monoclinic by single crystal X-Ray diffraction technique. The molecular structure was identified by IR, ¹H-NMR, ¹³C-NMR and elemental analysis. The crystal parameters of this compound are as follows: monoclinic P 2 1/n, a = 12.694(2) Å, b = 26.204(2) Å, c = 13.005(2) Å, β = 102.95(2)°, V = 4216.02(1) Å.³, Z = 4, Dx = 1.289 g/cm³, F(000) = 1704, λ (MoKα) = 0.71070 Å, μ = 0.2 mm^?1. The structure was solved by SHELXS-97 and refined by SHELXL-97. R = 0.06 for 3178 observed reflections with I > 2σ (I).     

Structure of bis(4-Methyl Pyridine) Cadmium Tetracyanonickelate

Abstract

The structure, C₁₆H₁₄CdN₆Ni, consist of corrugated polymeric networks made up of tetracyanonickelate ions coordinated to Cd. The 4-methyl pyridine molecules bound to Cd in trans positions are located on both sides of the network. The bonding in the networks occurs because of a departure of the Ni-C-N-Cd sequence of atoms from linearity at the C and N positions. The crystal structure of the title compound was determined as monoclinic by single crystal X-Ray diffraction technique. The crystal parameters of this compound are as follows: monoclinic C2/m, a=18.156(2) Å, b=7.581(2) Å. c= 6.983(2) Å, β = 110.09(2)°, V = 902.6(5) ų Z=2, Dx = 1.698 g/cm³, F(000) - 456, λ (MoKα) = 0.71070 Å, μ = 2.121 mm^?1. The structure was solved by SHELXS-86 and refined by SHELXL-93. R = 0.02 for 1074 observed reflections with I > 2[sgrave] (I).     

Structure of Quinoline-4-Carboxaldehyde-2,4-Dinitrophenyl-N Methylhydrazone

Abstract

The crystal structure of the title compound, C₁₇H₁₃N₅O₄, has been determined by single crystal x-ray diffraction at room temperature. The molecule is not planar, with dihedral angles of 7.2(1)° between the quinoline ring and N-methylhydrazone group, and 17.45(2)° between the N-methylhydrazone group and the phenyl ring. The crystal parameters of this compound are as follows: monoclinic P 21/n, a=9.525(2)Å, b = 15.192(2) Å, c = 11.302(2) A, β = 94.722(3)°, V = 1629.8(6) ų, Z = 4, Dx = 1.432 g/cm³, F(000) = 728, λ (MoKα) = 0.71070 Å, μ = 0.106 mm^?1, R_int = 0.017. The structure was solved by SHELXS-86 and refined by SHELXL-93. R = 0.07 for 2438 observed reflections with I > 2σ (I).     

Trissarcosine barium(2 + ) dibromide—a new complex of N‐methylglycine

We obtained a new complex containing sarcosine (CH₃NH₂⁺CH₂COO⁻) and barium(2 + ) dibromide (TSBB) in 3:1 molar ratio, as well as its deuterated analog. Single‐crystal X‐ray diffraction measurements show that TSBB crystallizes in the monoclinic system, space group P2(1)/c. The unit cell parameters are as follows: a = 18.345(4) Å, b = 10.668(2) Å, c = 8.9212(18) Å, β = 91.86(3)°, and Z = 4. The structure was determined with final R₁ = 0.0396 (for I > 2σI). The crystal possesses a pseudohexagonal symmetry down c axis showing the resemblance to the crystal structure of trissarcosine calcium chloride (TSCC). There are N HBr hydrogen bonds (HB) of six types. TSBB crystal undergoes a phase transition at 416 K (heating)–415 K (cooling) of continuous nature. The spectroscopic [Infrared (IR) and Raman] investigation of the crystal was performed at room temperature. The results are discussed with respect to the crystallographic data, as well as the results obtained for TSCC crystal. Copyright © 2008 John Wiley & Sons, Ltd.     

Crystal structure of the high-pressure modification of LaNbO4

Abstract

The crystal structure of the metastable LaNbO₄ high-pressure modification (HPM) has been studied by X-ray powder diffraction. It was found that the crystal structure of HPM LaNbO₄ belongs to- the room temperature BaMCF₄ -type structure (space group Cmc2₁, a = 3,941(1)Å, b= 14,460(4) Å, c = 5,681(2) Å, Z = 4).     

A Rule Governing Crystallization of Configurationally Directional Polymers: The Crystal Structure of the α and β Forms of Polypivalolactone

A “Rule” is proposed for incorporation of polymer chains having directional configuration, e.g. A‐B‐C‐A‐B‐C, into a crystal. Crystallization into a lamella morphology, as in slow crystallization from the melt, will incorporate antiparallel sequences (↑↓↑↓↑↓). Formation of a fiber by drawing the lamellar morphology must produce a different crystal structure containing parallel directional sequences. The drawn fiber must be polymorphic with a disordered aggregation of antiparallel and parallel crystal polymorphs. An example of this rule is found in the crystal structure of polypivalolactone. The melt crystallized α form is monoclinic, P2₁/c with a=9.05Å, b (fiber axis)=5.97Å, c=11.69Å, β=121.4° and consists of planar antiparallel sequences. The molecular conformation is a folded zig‐zag arrangement. On drawing a fiber, a disordered second phase of parallel plus antiparallel sequences is created. The chain conformation is a slightly distorted extended zigzag. The crystal structure of the directionally disordered β form is metrically monoclinic, with a=5.95Å, b=10.32Å, c (fiber axis)=4.94Å, β=101.3°. Examples of several classes of crystalline polymers demonstrating this Rule are presented.     

Precious Metals - Part 2 - The Spectroscopic Characterisation and X-Ray Crystal Structure of Pd2(Pph3)3Cl5O

This work is on the synthesis and characterisation of a new phosphine stabilised palladium compound. the compound was first obtained from the rejects of cluster syntheses stored in the laboratory. Later on, it was prepared from PdCl₂ and triphenyl phosphine. the compound was characterised by ³¹P {¹H} NMR, UV/visible spectroscopy and elemental analysis. the crystal and molecular structure of Pd₂(PPh₃)₃Cl₅O was determined by X-ray analysis. the compound crystallizes in orthorhombic space group Pbca, N° 61, a = 19.009(2)Å, b=22.283(2)Å, c=23.726(2)Å, V=10050(20)ų, Z=8 residuals R[I>2σ(I)]=0.0457 and R(all) = 0.0636, MoKα radiation, 20 °C.     

Dechannelling of 2 MeV He+ at a circular Frank dislocation loop in gold

The dechannelling cross section of a circular Frank dislocation loop of radius 19 Å, and of Burgers vector (a/3)(111) in gold crystal is calculated for (001) channeling of 2 MeV He⁺. The calculated value σ_c = 210 ± 10 Ų is satisfactory compared with the experimental value σ_e = 235 Ų by Merkel et al.     

Investigation of local lattice structure around Cr3+ ions at the trigonal and tetragonal sites in RbCdF3: Cr3+ crystal

The local lattice structure and EPR, optical spectra for Cr³⁺ doped in RbCdF₃ crystal have been studied by diagonalizing the complete energy matrices. The results show that the local structure of the Cr³⁺ ions in RbCdF₃ exhibits a compressed distortion at the trigonal and tetragonal sites. The compressed distortion can be ascribed to the fact that the radius of Cr³⁺ ion is smaller than that of Cd²⁺ ion, and therefore Cr³⁺ ion will draw the fluorin ligands inwards. The variational ranges of the local structural parameters for Cr³⁺ doped in RbCdF₃ crystal R =?1.9491 Å ～?1.9814 Å, θ?= 55.234° ～?55.286° at the trigonal site and R ₁ =?1.8617 Å ～?1.8928 Å, R ₂ =?1.9527 Å ～?1.9851 Å at tetragonal site are obtained respectively, and the EPR and optical spectra agree well with the experimental results.     

Mössbauer spectra and molecular structure of spin-crossover iron (III) complexes of monoclinic form with hexadentate ligands derived form triethylenetetramine and salicylaldehyde [Fe(sal2trien)]BPh4·acetone

Iron (III) complexes of [FeL]BPh₄·acetone containing the hexadentate ligand derived from triethylenetetramine and salicylaldehyde have been synthesized. These complexes were grown in two crystalline forms; monoclinic and twin crystals. The spin-state interconversion rate of the monoclinic form is as fast as the inverse of the Mössbauer lifetime (1×10^?7 s) above 200 K. The crystal structure of the monoclinic form (complex a) was determined at 290 K and to be of space group P2₁/a, with a=27.418 (4), b=10.097 (2), c=14.726 (3) Å, β=98.00 (1)°, and Z=4. The average bond distances of Fe?O (1.875 Å), Fe?N_imine (1.988 Å) and Fe?N_amine (2.069 Å) are in good agreement with the expected values for the transition spin-state between high- and low-spin states. Twin crystals are in a high-spin state over the temperature range 78–320 K.     

Crystal structure refinement of AlN and GaN

We have refined the structure parameters of AlN and GaN using X-ray intensities from single crystals collected with an automatic single crystal diffractometer. The lattice constants and the u values are a = 3.110 Å, c = 4.980Å, u = 0.3821 for AlN and a = 3.190Å, c = 5.189 Å, u = 0.377 for GaN. The final R-values for anisotropic temperature factors are equal to 0.015 for AlN and 0.026 for GaN. The effective atomic charges in these compounds are estimated.     

15N Isotopic Effects on the Raman Spectra of Tribromoacetamide

Abstract

¹⁵N-Tribromoacetamide has been synthesized with an isotopic content of 99, 4%, its Raman spectra have been recorded in the range 4.000–50 cm^?1. The isotopic shifts arising from ¹⁵N have been determined and interpreted. We have assigned the vibrational spectra of Br₃CCONH₂ and some overtones, combinations and difference bands. The molecular structure of tribromoacetamide has been studied employing the Ab Initio teoretical calculations and the Teller - Redlich isotopic product rule has been applied by assuming these geometrical parameters:

rCN = 1.4623 Å, rCC = 1.6014 Å, rBrC = 1.9468 Å, rCO = 1.2144 Å, rNH = 1.0292 Å, C-C-Br = 108.83320, C-C-0:118.2440, C-C-N:120.4137, C-N-H:110.45930     

Synthesis,Crystal Structure,and Magnetic Properties of the YbFeTi<Subscript>2</Subscript>O<Subscript>7</Subscript> Compound

We report on the synthesis conductions and results of experimental investigations of the crystal structure and magnetic properties of a new magnetic compound YbFeTi₂O₇. According to the X-ray diffractometry data, the crystal structure of the investigated compound is described by the rhombic space group Pcnb with unit cell parameters of a = 9.8115(1) Å, b = 13.5106(2) Å, and c = 7.31302(9) Å and atomic disordering in the distribution of iron ions Fe³⁺ over five structural sites. The magnetic measurements in the lowtemperature region revealed a kink in the temperature dependence of the magnetic moment and its dependence on the sample magnetic prehistory. The experimental results obtained suggest that with a decrease in temperature the sample passes from the paramagnetic state to the spin-glass-like magnetic state characterized by a freezing temperature of T _f = 4.5 K at the preferred antiferromagnetic exchange coupling in the sample spin system. The chemical pressure variation upon replacement of rare-earth ion R by Yb in the RFeTi₂O₇ system does not change the crystal lattice symmetry and magnetic state.     

A new molecular C60 complex with bis(methylenedithio)tetrathiafulvalene (BMDT-TTF): Synthesis, crystal structure, and properties

A new molecular C₆₀ complex of the composition (BMDT-TTF) · C₆₀ · 2CS₂ (I) with the bis(methylenedithio)tetrathiafulvalene (BMDT-TTF) organic donor is synthesized. The molecular and crystal structures of this complex are determined by x-ray diffraction. The (BMDT-TTF) · C₆₀ · 2CS₂ (I) compound crystallizes in a monoclinic crystal system. The main crystal data are as follows: a=13.550(5) Å, b=9.964(7) Å, c=17.125(8) Å, β=99.52(4)°, V=2280(2) ų, M=1229.45, and space group P2₁/m. Crystals of I have a layered structure: layers consisting of C₆₀ molecules alternate with layers composed of BMDT-TTF and CS₂ molecules. It is found that, in complex I, the donor and C₆₀ molecules are linked through the shortest contacts, which leads to a change in the molecular geometry of BMDT-TTF. The donor molecules in a crystal layer are characterized by the shortest S...S contacts. The IR data indicate the electroneutrality of the fullerene molecule. The electrical conductivity of (BMDT-TTF) · C₆₀ · 2CS₂ single crystals is measured using the four-point probe method at room temperature: σ_RT=2×10^?5 Ω^?1 cm^?1.     

Cation disorder and structural studies on Bi4−x Nd x Ti3O12 (0.0≤x≤2.0)

Here we report the results of combined powder X-ray and neutron diffraction studies of Bi_4?x Nd _x Ti₃O₁₂ (0.0 ≤ x ≤ 2.0) compositions. The parent Bi₄Ti₃O₁₂ has an orthorhombic lattice (space group: B2cb) with unit cell parameters a = 5.4432(5) Å, b = 5.4099(5) Å and c = 32.821(2) Å, and V = 966.5(1) ų. This orthorhombic lattice is retained in all the studied compositions. The unit cell parameters gradually decrease with Nd³⁺ ion concentration with a discontinuity at x = 0.75. Orthorhombicity of the lattice decreases with increase in Nd³⁺ content in the lattice. The orthorhombic unit cell parameters for a representative Bi₂Nd₂Ti₃O₁₂ composition are: a = 5.3834(9), b = 5.3846(9) and c = 32.784(1) Å. The observed orthorhombic distortion at x = 2.0 is very small and thus the crystal structure apparently has a pseudo-tetragonal lattice. In addition, Nd³⁺ preferentially substitutes in the perovskite slab of the Aurivillius structure. The fraction of Nd³⁺ in the fluorite slab increases with increase in Nd³⁺ contents.     

Mictomagnetic State in an EuBaCo<Subscript>2–<Emphasis Type="Italic">x</Emphasis></Subscript>O<Subscript>5.5–δ</Subscript> Single Crystal

The magnetic properties of an EuBaCo_1.9O_5.36 single crystal are studied in the temperature range T = 2–300 K and the magnetic field range H ≤ 90 kOe. This binary layered cobaltite single crystal has vacancies in the cobalt and oxygen sublattices, in contrast to the stoichiometric EuBaCo₂O_5.5 composition. All cobalt ions in EuBaCo1.9O5.36 are in a trivalent state. The single crystal has an orthorhombic structure with space group Pmmm, and its unit cell parameters are a = 3.883 Å, b = 7.833 Å, and c = 7.551 Å. The field and temperature dependences of the magnetization of the single crystal demonstrate that it is ferrimagnet below T_C = 242 K. At T < 300 K, all three spin states of the Co³⁺ ions are present. The nearest-neighbor interactions give antiferromagnetic (AFM) and ferromagnetic (FM) contributions to the exchange energy. The ratio of the AFM to the FM contributions changes when temperature decreases because of a change in the spin state of the Co³⁺ ions. The single crystal exhibits signs of mictomagnetism at low temperatures in high magnetic fields. At T = 2 K and H = 90 kOe, the zero-field and nonzero-field magnetizations are strongly different because of a uniaxial magnetic anisotropy, which tends to set magnetization along the magnetic field applied in cooling throughout the crystal volume. As a result, a complex ferrimagnetic structure with a noncollinear direction of Co³⁺ spins appears. The following phenomena characteristic of mictomagnets are also observed in the EuBaCo_1.9O_5.36 single crystal: a shift in a magnetization hysteresis loop when temperature decreases, retained hysteretic phenomena and no magnetization saturation in high magnetic fields, and an orientation transition. The mictomagnetic state in EuBaCo_1.9O_5.36 is shown to be caused by the structural distortions induced by vacancies in the cobalt and oxygen sublattices and by the frustration of AFM and FM exchange interactions.     

Structural characterization,spectroscopic, thermal,AC conductivity and dielectric properties and antimicrobial studies of (C8H12N)2[SnCl6]

A new inorganic-organic hybrid material produced from 2,6-dimethylanilinium cations and tin halide (SnCl₆)^2? has been synthesized and structurally determined by X-ray diffraction method. The title compound crystallizes in the monoclinic system, space group C2/m with a = 19.8772(4), b = 6.9879(1), c = 8.3001(2) Å, β = 98.487(2)° and V = 1140.26(4) ų. The crystal structure is built up of sheets of (SnCl₆)^2? octahedral anions and 2,6-xylidinium cations. The optical band gap was calculated and found to be 4.11 eV. At high temperature this compound exhibits a structural phase transition at 338 K. This has been characterized by differential scanning calorimetric and dielectric studies. Measurements of AC conductivity as a function of frequency at different temperatures indicated the hopping conduction mechanism. The bioassay results showed that the structure exhibits significant antibacterial activity.     

3,4,9,10 - Tetrathioperylene - I1.28, a new highly conducting,incommensurate organic charge transfer salt

We report here the preparation of TTP - I_1.28 (TTP = 3,4,9,10 - Tetrathioperylene), the crystal structures of TTP and its complex TTP - I_1.28 and their electrical conductivities. The crystal structure of TTP consists of two inequivalent types of segregated stacks with intermolecular planar spacings of 3.43 Å, and 3.47 Å. The crystal structure of TTP - I_1.28 consists of two incommensurate sublattices. The TTP sublattice is built up by segregated stacks of TTP molecules with interplanar spacing of 3.25 Å. The iodine sublattice consists of columns formed mainly by I₃ units. The electrical conductivity is very weakly metallic at room temperature and turns to a semiconducting behavior at 220 K with an activation energy of 15 meV.     

DFT studies on a high-energy density cage compound 1, 3, 5, 7, 9, 11-hexo(N(CH3)NO2)-2, 4, 6, 8, 10, 12-hexaazatetracyclo[5, 5, 0, 0, 0] dodecane

The infrared and Raman spectra, heat of formation (HOF) and thermodynamic properties were investigated by B3LYP/6-31G^** method for a new designed polynitro cage compound 1,3,5,7,9,11-hexo(N(CH₃)NO₂)-2,4,6,8,10,12-hexaazatetracyclo[5,5,0,0,0]dodecane. The detonation velocity (D) and pressure (P) were predicted by the Kamlet–Jacobs equations based on the theoretical density and condensed HOF. The bond dissociation energies and bond orders for the weakest bonds were analysed to investigate the thermal stability of the title compound. The computational result shows that the detonation velocity and pressure of the title compound are superior to those of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), but inferior to those of 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane (HMX) and hexanitrohexaazaisowurtzitane (HNIW). And the analysis of thermal stability shows that the first step of pyrolysis is the rupture of the N₇–NO₂ bond. The crystal structure obtained by molecular mechanics belongs to the P2₁ space group, with the lattice parameters Z = 2, a = 11.8246 Å, b = 10.4632 Å, c = 15.9713 Å, ρ = 1.98 g cm^?3.