Crystal Structure and Thermal Phase Behaviour of 2,3-Dicyano-4-n-hexyloxyphenyl-trans-4-n-heptyleyelohexanoate

The title compound with the formula C₇H₁₅ C₆H₁₀ COO C₆H₂(CN)₂ OC₆H₁₃ (DHPHC) crystallizes in the monoclinic space group P 21/n with a = 5.633(1), b = 14.254(1), c = 33.435(7) Å, β = 91.56(2)°, and four molecules per unit cell. The structure has been solved by direct methods and refined to R = 0.082. The DHPHC molecules adopt a banana-shaped but considerably stretched form and show a parallel arrangement of their long axes in the crystal lattice. The phase transitions of DHPHC have been investigated by DSC and thermal microscopy. The compound shows a rather complicated melting behaviour and forms two solid phases and a monotropic smectic A phase.     

The crystal and molecular structure of the Nematogenic Compound 5,8-Dihydro-5,8-methano-1,4-naphthalenediyl Bis(4-ethoxybenzoate)

Single crystals of the title compound with the formula (C₂H₅O C₆H₄ COO)₂C₁₁H₈ have been investigated by X-ray analysis. The compound crystallizes in the monoclinic space group P2₁/n with a = 8.555(1), b = 15.280(2), c = 19.093(3) Å, β = 94.17(1)⁰, V = 2489.2(5) ų, and Z = 4. The structure was solved by direct methods and refined to a final R value of 0.062 The molecule adopts an almost stretched form. The norbornene skeleton within the central part of the molecule is disordered and occurs in two different conformations. The molecular packing is characterized by different lattice regions: the molecules in one region are parallel but their long axes are inclined by 49.5° to the molecules of the other region.     

The crystal and molecular structure of 2,5-dibromo-1,4-phenylenediyl bis(trans-4-ethylcyclohexanoate)

The title compound with the formula C₂H₅ C₆H₁₀ COO-C₆H₂Br₂ OOC C₆H₁₀ C₂H₅ (DPBEC) crystallizes in the monoclinic space group P2₁/c with a = 15.37(2), b = 5.27(1), c = 15.13(2) Å, β = 92.7(1)° and two molecules per unit cell. The structure was solved using film intensity data by heavy atom method and refined to R = 0.078. The fully stretched DPBEC molecules exhibit exact C_i symmetry. Their packing in the crystal is characterized by a non-parallel (cross) arrangement of the molecular long axes.     

The crystal structure of nematogenic 2-bromo-1,4-phenylenediyl bis(trans-4-n-propylcyclohexanoate) — a special kind of disorder

The title compound with the formula C₃H₇–C₆H₁₀–COO–C₆H₃Br OOC C₆H₁₀ C₃H₇ (BPBPC) crystallizes in a triclinic unit cell with dimensions a = 5.822(2), b = 8.732(3), c = 13.016(5) Å, α = 94.42(3)°, β = 93.47(3)°, γ = 104.85(2)° containing one molecule. The structure has been solved by heavy atom method and refined to R = 0.083. The BPBPC molecules adopt an optimum stretched form and exhibit pseudo-centrosymmetry in consequence of a special kind of disorder within the crystal lattice.     

The crystal and molecular structure of three homologue 1,4-dialkanoyloxy-biphenyls (SYM-n)

The three homologue compounds with the general formula C_nH_2n+1 COO C₆H₄ C₆H₄ OOC C_nH_2n+1 (SYM-n) crystallize in the following space groups: SYM-1: triclinic, P1 , a = 7.400(6), b = 9.227(3), c = 10.579(3) Å, α = 85.97(3), β = 89.09(3), γ = 71.47(3)°; SYM-2; monoclinic, P2₁/c, a = 11.712(7), b = 5.648(1), c = 12.408(6), Å, β = 103.84(3)°; SYM-5: triclinic, P1, a = 5.505(4), b = 8.342(8), c = 24.79(2) Å, α = 86.67(3), β = 85.45(6), γ = 71.74(7)°. The structures have been solved by direct methods and refined to R = 0.075, 0.061 and 0.053, respectively. The packing arrangements show a layer-like structure. The layers are almost separated for SYM-1 as well as for SYM-2 and interdigitated for the structure of SYM-5.     

The Crystal and Molecular Structure of 4'-Cyanophenyl-4-n-Pentylbenzoate

The crystal and molecular structure of the title compound with the formula C₅H¹¹—C₆H₄—COO—C₆H₄—CN (CPPB) has been determined by X-ray diffraction methods. CPPB crystallizes in the monoclinic space group P2₁/n with eight molecules in a unit cell of dimensions a = 15.268(2) Å, b = 9.165(1) Å, c = 24.031(3) Å, β = 94.67(1)°. The structure has been solved by direct methods and refined to an R value of 0.070.

The CPPB molecules adopt a stretched form and are packed in an approximate parallel imbricated mode, the molecular long axes making an angle of about 5° with the crystal c axis. The molecular geometry and packing are discussed in relation to the mesomorphic behavior of CPPB.     

Die Änderung der Molekül- und Kristallstruktur des N-Methyl-piperidinum-acet-meta-chlor-anilid-jodid durch Einlagerung von Wasser

N-Methyl-piperidinium-acet-meta-chloro-anilide-iodide crystallizes from water in the space group Pna2₁ with 4 formula units C₁₄H₂₀N₂OClJ and 4 H₂O molecules in the unit cell. The lattice constants are a = 12.413 Å, b = 19.798 Å and c = 6.919 Å. The change of the molecular conformation caused by water molecules was investigated by X-ray structure analysis.     

Crystal and Molecular Structure of Non-hydrated and Hydrated Piperidinium-acet-o-Cl-anilide-chloride

Crystallizations from water and alcoholic solution respectively yield different crystal and molecular structures of Piperidinium-acet-o-Cl-anilide-chloride. The non-hydrated compound crystallizes from alcoholic solution in the space group P 2₁/c with 4 formula units C₁₃H₁₈N₂OCl₂ in the unit cell of dimensions a = 12.352 Å, b = 6.864 Å, c = 19.018 Å and β = 113.98°. The hydrated modification has the space group C 2/c with 8 formula units C₁₃H₁₈N₂OCl₂ and 8 H₂O molecules in the unit cell. The lattice constants are a = = 24.159 Å, b = 8.966 Å, c = 14.179 Å and β = 90.50°. The X-ray structure analyses were carried out to investigate the hydrogen bonds and the change of the molecular conformation caused by linking of water molecules to the drug molecules.     

Die Molekül- und Kristallstruktur des N-Methyl-piperidinium-acet-para-brom-anilid-jodid

N-Methyl-piperidinium-acet-para-bromo-anilide-iodide crystallizes in the triclinic space group P 1 with two formula units C₁₄H₂₀N₂OBrJ and two H₂O molecules in the unit cell. The lattice constants are a = 8.950 Å, b = 14.721 Å, c = 7.440 Å, α = 80.19°, β = 112.57° and γ = 106.82°. The molecular structure of the compound was determined by the X-ray structure analysis and the interaction between the molecules in the crystal was investigated. Especially the influence of the water in the crystal on the form of the molecule was analysed.     

Crystal and Molecular Structure of the Nematogenic Compound 4′-Cyanophenyl-4-n-Pentoxybenzoate

The title compound with the formula C₅H₁₁O-C₆H₄-COO-C₆H₄-CN (CPPOB) crystallizes in the orthorhombic space group Pnam with a = 16.465 Å, b = 13.577 Å, c = 7. 621 Å and four molecules per unit cell. The structure has been solved by direct methods and refined to a final R value of 0.050. The CPPOB molecules have exact C_s symmetry as a consequence of their location on crystallographic mirror symmetry planes, the benzene ring to which the cyano group is attatched has a perpendicular orientation to the other ring in the plane. The molecules adopt a nearly optimal stretched form, neighbouring molecules make an angle of 35.2°. The results are discussed in relation to the mesomorphic behaviour of CPPOB.     

Static Disorder in Hexagonal Crystal Structures of C60 at 100 K and 20 K

C₆₀ · 2C₈H₁₀ (100 K): hexagonal space group P6₃, a = 23.694(4), c = 10.046(2) Å, V = 4884(2) ų, D_x = 1.903 g cm⁻³, Z = 6, F(000) = 2856, γ(CuKa) = 1.54178 Å, μ = 0.84 mm⁻¹. C₆₀ · 2C₈H₁₀ (20 K): hexagonal space group P6₃, a = 23.67(1), c = 10.02(1) Å, V = 4862(6) ų, D_x = 1.912 g cm⁻³, Z = 6, F(000) = 2856, γ(CuKa) = 1.54178 Å, μ = 0.84 mm⁻¹. The structures were determined by Patterson syntheses and rigid-body refinements. The C₆₀ molecules show two orientations with one molecular centre in common. The solvent molecules are disordered too. Static disorder could not be overcome or influenced by cooling down. A coordination number of 10 was found for the fullerene molecules.     

Crystal and Molekular Structure of Piperidinium-acet-p-Cl-anilide-chloride

Piperidinium-acet-p-Cl-anilide-chloride crystallizes in the triclinic space group P 1 with 2 formula units C₁₃H₁₈ON₂Cl₂ in the unit cell. The lattice constants are a = 10.471 Å, b = 12.545 Å, c = 6.149 Å, α = 72.14°, β = 105.70° and γ = 105.21°. Bond lengths, bond angles and the conformational flexibility were determined by X-ray structure analysis. The crystal structure contains dimeres consisting of drug molecules connected by hydrogen bonds.     

Structural Properties of S-alkylated Dithiolene Chelates (I). Crystal and Molecular Structures of Bis(S-ethyl-ethene-1,2- dithiolato)palladium (II) and Bis(S-ethyl-ethene-1,2-dithiolato) platinum (II)

Bis(S-ethyl-ethene-1,2-dithiolato)palladium(II), Pd(S₂C₄H₇)₂, is monoclinic, P 2₁/n, with a = 7.598(1) Å, b = 10.445(2) Å, c = 8.031(1) Å, β = 95.3(1)° and Z = 2. The structure was determined by 893 independent reflections and refined by the block-diagonal leastsquares method to R = 0.12. The chelate molecule is nearly planar and the palladiumsulfur distances are 2.278(6) Å and 2.403(6) Å. Bis(S-ethyl-ethene-1,2-dithiolato)platinum(II), Pt(S₂C₄H₇)₂, is monoclinic, P 2₁/a, with a 13.114(2) Å, b = 12.873(2) Å, c = 7.446(2) Å, β = 96.1(1)° and Z = 4. The structure was solved from 2040 independent reflections. The compound is not isomorphic with the isomeric palladium complex. In the unit cell there exist two symmetry independent molecules. The platinum-sulfur distance is 2.280 (6) Å.     

X-ray Diffraction Study on MgSeO4. 6 H2O at Elevated Temperatures

The dehydration of MgSeO₄. 6 H₂O has been studied using an X-ray powder diffraction method at elevated temperatures. Five different solid phases have been identified in the temperature interval of 20–450 °C: MgSeO₄. 6 H₂O; MgSeO₄. 5 H₂O (with a small amount of MgSeO₄. 4 H₂O), MgSeO₄. 2 H₂O, amorphous MgSeO₄ and crystalline MgSeO₄. MgSeO₄. 5 H₂O crystallizes in the triclinic system with the lattice parameters: a = 6.403(2) Å, b = 10.576(5) Å, c = 6.196(3) Å, α = 98.63(2)°, β = 110.36(2)°, γ = 75.25(3)°, SG P1 . MgSeO₄. 2 H₂O forms orthorhombic crystals with lattice parameters: a = 10.304(1) Å, b = 10.351(9) Å, c = 9.138(9) Å. The crystalline anhydrous magnesium selenate crystallizes in the orthorhombic system with the lattice parameters: a = 4.925(2) Å, b = 9.026(5) Å, c = 6.816(6) Å. Additionally MgSeO₄. 4 H₂O has been prepared and studied roentgenographically: monoclinic system with the lattice constants: a = 6.064(4) Å, b = 13.773(7) Å, c = 8.062(6) Å, β = 91.82(7)°, SG P2₁/n. According to expectation the magnesium selenate hydrates are isomorphous with the corresponding magnesium sulphate hydrates.     

Crystal and molecular structures of 2-amino-5-(m-nitrophenyl)-1,3,4-Thiadiazole

2-Amino-5-(m-nitrophenyl)-1,3,4-thiadiazole (C₈H₆N₄O₂S) is studied using IR and ¹H NMR spectroscopy and X-ray diffraction (CAD4 automated diffractometer, λMoK _α, graphite monochromator, 957 unique reflections, Patterson method, R = 0.0326). The crystals are monoclinic, a = 11.832 Å, b = 9.862 Å, c = 8.353 Å, β = 110.40(3)°, V = 913.6(3) ų, d _calcd = 1.212 g cm^?3, μ(MoK _α) = 0.253 mm^?1, Z = 4, and space group P2₁/c. In the crystal, the C₈H₆N₄O₂S molecules form infinite layers parallel to the xz plane. Each layer contains aromatic rings with nitro groups that deviate from the layer plane on either side of the layer. In the packing, the aromatic rings with nitro groups of one layer fill spaces between aromatic rings with nitro groups of the adjacent layers.     

Crystal and molecular structure of the chiral compound 4–(2–methylbutyloxy)phenyl–4–(2-propenyloxy)-benzoate,C21H24O4

The enantiomeric [(S)-(–)-MBP3B] and the racemic form [(±)-MBP3B] of the title compound with the formula C₃H₅O–C₆H₄–CO₂–C₆H₄–OC₅H₁₁ were studied by single crystal analysis at room temperature. (S)-(–)-MBP3B crystallizes in the orthorhombic space group P2₁2₁2₁ with a = 7.835(3) Å, b = 11.093(6) Å, c = 44.820(3) Å and 8 molecules per unit cell. The structure was determined from 966 reflections with intensities > 3σ. The refinement with isotropic temperature factors leads to R = 0.094. The crystals of the racemic form are monoclinic, space group P2₁/a with a = 7.899(5) Å, b = 11.046(6) Å, c = 22.845(12) Å, β = 99.28(3)°, Z = 4.1236 diffractometer data (I > 3σ) were refined by least-squares methods with anisotropic temperature factors for the non-H atoms to R = 0.070. The packing arrangement for both forms shows a layer-like structure with very similar packing coefficients, k = 0.7085 for the pure enantiomer and k = 0.7014 for the racemic form.     

Crystal and Molecular Structure of Piperidinium-acet-m-Cl-anilide-chloride

Piperidinium-acet-m-Cl-anilide-chloride crystallizes in the orthorhombic space group Pca2₁ with 4 formula units C₁₃H₁₈ON₂Cl₂ in the unit cell. The lattice parameters are a = 10.348 Å, b = 12.280 Å and c = 11.335 Å. The crystal structure was determined by the heavy atom method and refined by least-squares procedures to the conventional R = 0.045. Bond lengths, bond angles and the conformation of the drug molecule were determined. Cl⁻ ions are linked to the molecules by hydrogen bonds forming chains together with iones and molecules related by the a-glide plane.     

Synthesis and crystal structure of 3-ammonium-4-hydroxyphenyl sulfonate hemihydrate

The crystal structure of 3-ammonium-4-hydroxyphenyl sulfonate hemihydrate C₆H₃(NH₃)(OH)SO₃ · 0.5H₂O is determined by single-crystal X-ray diffraction. The unit cell parameters are as follows: a = 11.2395(3), b = 10.3814(3), c = 13.7509(4) Å, β = 100.326(1)°, V = 1578.49(8) ų, space group P2₁/n, Z = 4. The crystal structure can be described us a succession of infinite corrugated layers parallel to ab plane. These layers consist of rings formed by four sulfonate molecules located around a center of symmetry. The rings are connected to each other and to water molecules via O-H...O hydrogen bonds. The structure is further stabilized by π-π interactions between phenyl rings of organic entities of successive layers.     

Molecular and crystal structures of chiral 2-(4-phenylbenzylidene)-3-methyl-6-isopropylcyclohexanone 6-bromo derivative

The molecular and crystal structures of chiral 3R, 6S-2-(4-phenylbenzylidene)-3-methyl-6-bromo-6-isopropylcyclohexanone C₂₃H₂₅BrO (Ia) are determined by X-ray diffraction. Crystals Ia are monoclinic, a = 11.005(4) Å, b = 12.229(4) Å, c = 14.376(5) Å, β = 91.37(1)°, Z = 4, and space group P2₁. The geometric parameters of two crystallographically independent molecules are close to each other in magnitude. The cyclohexanone ring adopts a chair-type conformation with an equatorial isopropyl substituent and an axial orientation of the methyl group and the C-Br bond. The 3,6-alkyl groups are in the cis position with respect to the cyclohexanone ring. It is demonstrated that, in the series of 6-bromo substituted compounds, as in their analogues unsubstituted for bromine in the 6-position, the maximum flattening of the cinnamoyl fragment O=C-C=C-C₆H₄ X is observed in the structure with X = C₆H₅.     

Crystal and Molecular Structure of 1-Ethyl-3-[tris(trimethylsiloxanyl)silyl]pyrrolinium Hydrochloride

The crystal and molecular structure of 1-Ethyl-3[tris(trimethylsiloxyl)silyl]pyrrolinium hydro-chloride (C₁₅H₃₈N⁺O₃Si₄ · C¹⁻) has been determined by direct methods. The title compound crystallizes in the monoclinic space group C2/c with a = 20.640(3), b = 19.494(2), c = 27.34(3) Å, β = 90.60(4)°, V = 11000(13) ų, Z = 16, D_x = 1.034 Mg m⁻³. There are two molecules with different conformations in the crystal. The pyrroline rings are non-planar.-The Si O Si angles range from 149(1)° to 163(1)°. Two of the SiMe₃ groups are disordered. All molecules are connected by C¹⁻ – N⁺ contacts and C¹⁻ - HN⁺ hydrogen bonds to form double chains.