The molecular and crystal structure of p-methyl-phenyl glyoxylacid-m-trifluoro-anilide

Using X-ray crystal structure analysis of the title compound the positions of all atoms (including all A atoms) were localized in the triclinic unit cell with the parameters a = 14.68₆ Å, b = 7.70₀ Å, c = 7.89₈ Å, α = 122.5°, β = 105.4°, γ = 87.7°, space group P1. The existence of an intramolecular H N … O(1) bridge was inferred, the H-bridge acceptor of which predominantly is the π-electron density of the carbonyl group in agreement with the results of the X-ray crystal structure analysis of p-methyl-phenyl-glyoxyl-acid-p-chloroanilide (HOEHNE , SEIDEL ). Moreover, the existence of H-bridgelike interactions of the two phenyl hydrogen atoms H(6) and H(15) to the carbonyl oxygen O(2) could be proved. These interactions stabilize the conformation of the two phenyl rings in the molecule.     

The crystal and molecular structure of 2-S-methylthiouracil

2-S-Methylthiouracil crystallizes in the triclinic space group P with unit cell dimensions a = 5.508(4), b = 7.175(3), c = 8.522(2) Å, = 80.83(2), = 80.43(3), = 76.86(3)°, and Z = 2. The molecule exists in the crystal in the lactam form and is essentially planar. The molecular packing consists of molecules linked in centrosymmetric hydrogen-bonded pairs. The effects of methylation and subsequent metallation on the 2-thiouracil structure are discussed.     

The molecular and crystal structure of the Steroidal Alkaloid Aculeamine

A new solanocapsine-type alkaloid named aculeamine has been isolated from roots of Solanum aculeatum and its structure has been established by X-ray analysis as 22,26-epimino-23β-methoxy-16α,23-epoxy-5α,25αH,25βH-chloestane-3β-ol. The compound crystallizes in the hexagonal space group P6₁ with the lattice parameters a = b = 16.706, c = 17.056 Å, α = β = 90°, γ = 120°. The final residual value was R = 0.079.     

The molecular and crystal structure of 2-oxo-1-pyrrolidine-acetamide

C₆H₁₀N₂O₂, P1 , a = 6,607(2) Å, b = 8,538(2) Å, c = 6,392(2) Å, α = 102,43(2)°, β = 91,11(2)°, y = 79,82(2)°, V = 349,1 ų, Z = 2, D_m = 1,36 g × cm⁻³, D_x = 1,35 g × × cm⁻³, MoKα radiation, λ = 1.71069 Å, μ(MoKα) = 1.11 cm⁻¹. The structure was solved by direct methods. The parameters were refined by full matrix least squares technique to a final R = 0.088 for 834 reflections with ∥F₀∥ > 4σ(F₀). The dihedral angle between the least-squares plane through the pyrrolidine ring and that through the acetamide group is 90.4°. The N H … O hydrogen bonds connect molecules to form bands parallel to the z axis.     

The stereochemistry of organosulfur compounds. XX. The x-ray crystal and molecular structures of two tetrathiaspiroalkanes

The X-ray crystal structures of 1,4,6,9-tetrathiaspiro[4.4]nonane (4) and 1,5,7,11-tetrathiaspiro[5.5]undecane (3) have been determined. Crystals of4 are tetragonal, space groupI4₁ cd, with eight molecules in a unit cell of dimensionsa=9.521 (2) andc=19.052(5) Å. Crystals of3 are orthorhombic,Pbca, with eight moleucles in a cell havinga=8.955(3),b=12.356(4), andc=18.425(4) Å. Compound4 was solved from the Patterson map and3 by use ofMultan, and they refined to finalR values of 6.4 and 2.5%, respectively. Compound4 consists of two 1,3-dithiolane rings connected via C(2), both of which appear to be somewhat disordered at room temperature. The uncorrected C-C distance is 1.476 Å and the average S-C distance is 1.786 Å. Compound3 consists of two 1,3-dithiane rings connected at C(2), both in chair conformations. In both compounds there appear to be electronic repulsions between S lone pairs and axial hydrogens of the opposite ring system. Analysis of endocyclic torsion angles in3 indicates that the ring conformations themselves are not significantly altered by the positional shift caused by the repulsion.     

The crystal and molecular structure of the steroidal alkaloid 20-epi-kibataline

The major constituent of the alkaloid fraction of the leaves of Paravallaris macrophylla Pierre has found to be the new paravallarine-type steroidal alkaloid 20-epi-kibataline. The structure of this steroidal alkaloid has been determined by X-ray analysis. The compound crystallizes in the monoclinic space group P2₁ with the lattice parameters a = 11.286, b = 14.250, c = 6.206 Å, β = 97.88°. The final R value was 0.067.     

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 bis(tetramethylammonium) hexamolybdate(VI)

The crystal structure of the title compound, C₈H₂₄N₂Mo₆O₁₉ was determined by single crystal X‐ray diffraction technique. The crystals are trigonals, space group P‐3c1, with a = b = 10.0176(11) Å, c = 14.089(2) Å, γ = 120°, V = 1224.4(3) Å₃, Z = 2. The structure was solved by direct methods and refined by least‐squares methods to a Final R = 0.0316 for 1114 observed reflections with I > 2σ(I). In hexamolybdate anion, six MoO₆ distorted octahedra are fused together so that they all share a common vertex. O atoms are of three types: central, terminal and bridging, bonded to six, one and two Mo atoms, respectively. The crystallographic data of the structure was deposited with the Cambridge Data Center as No. CCDC 199679. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The crystal and molecular structure of an epoxide,C30H50O

The compound C₃₀H₅₀O (7,8-epoxy-9(87)-abeofriedelane),M _r=376.33, orthorhombic, P2₁2₁2₁,a=11.819(1) Å,b=14.381(2)Å,c=15.402(2)Å,Z=4,D _c=1.083 gm cm^–3,R=0.055, for 1643 reflections (withI>2) out of 1743 unique reflections. The three dimensional structure determination is done to characterize the conformation of this series of compounds which has good promise for drug and for rational understanding of the reaction mechanism in the olefin stereochemistry and the structural basis of synthesis of these natural products.     

The crystal and molecular structure of 1,12-dibromododecane,C12H24Br2

The α,ω-dihaloalcanes could serve as model compounds for polyethylenes in further studies of infrared and Raman-spectra. The 1,12-dibromododecane, belonging to this class of compounds, has the monoclinic space group P 2₁/a with the cell parameters a = 24.8 Å, b = 5.40 Å, c = 5.50 Å, β = 99°, Z = 2. The preparation of crystals was very difficult. The crystal finally used gives only few and bad X-ray data measured by film method (equiinclination Weissenberg). Therefore the accuracy of the structure determination is not high, but the result is reliable and has model character for related compounds. All molecules are ordered with their long molecular axes parallel to the (401) planes of the unit cell. There are alternating plane layers of bromine atoms on the one hand and aliphatic parts of the molecules on the other hand, both parallel to the (100)-planes. This molecular arrangement explains well the spectroscopic and crystal optical properties of the structure and also of related compounds like 1,10-dibromodecane and 1,18-dibromooctadecane.     

The crystal and molecular structure of ammonium-bis(malonato) oxovanadium(IV) dihydrate

The title compound, (NH₄)₂[VO(C₃H₂O₄)₂]·2H₂O, crystallizes in the monoclinic space group P2₁/n, with a=7.1889(7), b=19.254(2), c=9.879(2) Å, β=108.19(1)^o, and Z=4. The VO²⁺ cation is five-fold coordinated with two malonate anions acting as bidentate ligands and a water molecule. Infrared and Raman spectra are also reported to attain a wider insight into the compound characteristics.     

Refinement of the crystal and molecular structure of tetraacetylethane by neutron diffraction

The structure of tetraacetylethane has been determined by neutron diffraction. The compound exists in the dienolic form, the enolic hydrogen being intramolecularly bonded to a neighbouring oxygen in a clearly asymmetric mode. The acetylacetonate residues are essentially planar.     

The crystal structure of dodecyltrimethylammoniumbromide

C₁₅H₃₄BrN, monoclinic, P 2₁/m, a = 21.603(9), b = 7.261(3), c = 5.636(2) Å, β = 86.85(2)°, Z = 2, V = 882.72 ų, D_x = 1.160 g/cm³, μ(MoKα) = 2.45 cm⁻¹, λ(MoKα) = 0.71069 Å. The structure of this cationic surfactant was solved with Patterson methods and refined to R = 0.091 for 2057 measured reflections. The dodecyl chains are slightly screwed around their chain axes. The hydrocarbon chains are statistically disordered. The polar regions satisfy the mirror plane which is by remaining parts only statistically fulfilled. In the process of structure refinement statistical disorder has been included by separation of some atom positions. The sublattice of the hydrocarbon chains is nearly O⟂ with a_s = 5.14, b_s = 7.26, c_s = 2.52 Å.     

The crystal structure of hexabenzoylhexaazaisowurtzitane

The crystal and molecular structure of an interesting cage compound is described. Crystal data: C₄₈H₃₆N₆O₆·(CH₃)₂CO; monoclinic; space group: P2 ₁ /n; a = 14.948(3) Å, b = 15.079(3) Å, c = 19.539(4)Å, = 93.93(3)°, V = 4394(2)ų; and Z = 4.     

The crystal and molecular structure of a dioxan photoadduct of 3-dehydro-gibberellin A1 methyl ester

The three-dimensional structure of a dioxan photoadduct of 3-dehydro-gibberellin A₁ methyl ester has been established as (2′S)-3-[dioxanyl-(2′)]-3-epi-gibberellin A₁ methyl ester (1) by X-ray analysis. The compound crystallizes in the orthorhombic space group P2₁2₁2₁ with four molecules in the unit cell of dimensions a = 9.751, b = 22.189, c = = 10.064 Å. The final R-value is 0.103 for 1151 reflections.     

X-ray and molecular mechanics studies on the crystal and molecular structure of the leucoacetate of ventilatone A

Molecular details of the leucoacetate of ventilatone A have been obtained by X-ray crystallographic and molecular mechanics calculations. In the crystalline state (space group P1,Z=2) the two independent molecules of the asymmetric unit appear to be disordered as some unusual geometrical features are evident. As these two molecules are related by a pseudo center of symmetry details of space group assignment are presented. Evidence of bond order in the molecules is supported by previously published spectroscopic data.     

The crystal and molecular structures of cyclohexanone thiosemicarbazone

Cyclohexanone thiosemicarbazone (Hchtsc) crystallizes in the triclinic crystal system with space group P (No. 2) and the following unit cell parameters: a = 6.2989(2), b = 7.9730(3), and c = 9.4118(2) Å = 79.607(3), = 85.519(2), and = 73.50(2)° V = 445.60(2) ų, Z = 2. The lengths of the bonds C(1)–S, C(1)–N(1), C(1)–N(2), and N(2)–N(3) suggest electron delocalization in all four. The S atom is trans to N(3), and this E configuration is stabilized by intramolecular hydrogen bonding between N(3) and the N(1)H₂ group. Two intermolecular hydrogen bonds involving the S atom and the N(1)–H(1b) and N(2)–H(2) groups give rise to a polymeric chain of molecule pairs.     

The crystal and molecular structure of dichloro-(bis-1,2-diphenylphosphinoethane)platinum(II)

Crystals of PtCl₂(PPh₂)(CH₂)₂(PPh₂) (1), produced from attempts to prepare hydridochloroplatinum complexes, are monoclinic, space groupP2 ₁ /c, with four molecules in a unit cell of dimensionsa=11.478(3),b=13.263(2)c=16.343(3) Å, and =99.00(2)°. The structure was solved by the heavy-atom method and refined by block-diagonal least-squares calculations with anisotropicthermal parameters;R=0.048 andR=0.061 for 1843 observed reflections. The crystal structure contains discrete well-resolved molecules. The Pt atom has distorted square-planar coordination with Pt-P 2.208(6), Pt-Cl 2.355 and 2.341(6) Å distances, and Cl-Pt-Cl 90.2(2) and P-Pt-P 86.3(2)° angles.     

The crystal and molecular structure of SnBr[N(SiMe3)2]3

The crystal structure of SnBr[N(SiMe₃)₂]₃ has been determined from three-dimensional X-ray diffraction data collected by counter methods. This compound crystallizes in the rhombohedral space groupR3c witha=11.970(3) Å, α=99.06(3)°, andZ=2forD _c> =1.37 g cm^?3. The finalR value was 0.027 based on 608 independent observed reflections. The molecule lies on a crystallographic three-fold axis which contains the Sn and Br atoms. The bromine atom is covalently coordinated to the tin atom at a Sn-Br separation of 2.519(2) Å. The three nitrogen atoms complete the bonding to tin with an Sn-N bond length of 2.056(7) Å.