Crystal and molecular structure of 1,1′-ferrocene-dicarbaldehyde

The crystal and molecular structure of 1,1-ferrocene-dicarbaldehyde 1 is reported. Crystal data for 1: monoclinic, space group P2₁/n, a = 5.876(1), b = 11.349(1), c = 29.460(3) Å, = 95.067(2)°, V = 1956.9(3) ų, and D _c = 1.64 g/cm³, for Z = 8. The complex crystallizes such that two molecules are located in the asymmetric unit in which the complexes display different degrees of twisting of the cyclopentadienyl (Cp) rings and formyl substituents about the Cp—Fe—Cp and Cp—COH axes, respectively. The molecule self-assembles in the solid state to form a 2D layered structure held together by - interactions and C—H···O hydrogen bonds.     

Crystal and molecular structure of 1,4-S,S′-bis-isothiosemicarbazidebutane dihydrobromide

The synthesis and crystal structure of 1,4-S,S-isothiosemicarbazidebutane dihydrobromide have been presented. The crystals are monoclinic:P2₁/n, a=7.9910(10),b=10.979(2),c=8.9240(10)Å, =111.450(10)°,Z=2, room temp. The structure was solved by direct methods. and refined to R=0.0297 for 846 reflections. The title compound consists of the centrosymmetric [C₆H₁₈N₆S₂]²⁺ dication and two Br^– anions. Intramolecular N–H...N and intermolecular N–H...Br hydrogen bonds stabilizetrans conformation of the thiosemicarbazide moiety.     

Crystal and molecular structure of 4′-hexyloxyphenyl 4-pentylbenzoate

The molecular and crystal structure of 4??-hexyloxyphenyl 4-pentylbenzoate, C₆H₁₃O-C₆H₄-COO-C₆H₄-C₅H₁₁, which is a liquid-crystal compound, was determined by X-ray diffraction. This compound forms a nematic phase upon melting. The crystal contains three crystallographically independent molecules. In one of them, the alkyl chain is disordered. This is indicative of the looseness of the crystal packing in the aliphatic region. The crystal structure is stabilized by the following two types of weak directional interactions: hydrogen bonds with the participation of the terminal O atom of the ester group and the C-H group of one of the benzene rings and C-H????-system interactions. Only one of the three independent molecules is involved in the latter type of interactions. Hence, the structurization of the mesophase is most likely determined by hydrogen bonding.     

Crystal and molecular structure of 2′,4′-dimethoxyflavone

C₁₇H₁₄O₄,M _r =282.3, triclinic,P-1,a=8.469(3),b=8.516(2),c=20.425(8)Å,=84.95(3),=81.98(3), =70.47(2)°,V=1373(13)ų,Z=4,D _x =1.365 g cm^–3, (MoK )=0.71069 Å,=0.91 cm^–1,F(000)=592,T=294K,R=0.038 for 3577 observed reflections (F>3 (F)). The asymmetric unit is composed of two molecules. These two molecules, which are in planar conformations, differ in 4-methoxyl group orientation. Short intramolecular contacts are found between the -benzopyran portion and the dimethoxyphenyl ring.     

Crystal structure of the meta hydroxyl phenyl analog of α(+)-prodine

The meta hydroxyphenyl analog of -prodine (1,3-dimethyl-(4-meta-hydroxy phenyl)-4-propionyloxypiperidine) free base crystallizes in the orthorhombic space group P2₁2₁2₁. The relative configuration of the compound shows the piperidine ring is in a chair conformation, the phenyl ring, the 3-methyl, and the N-methyl are equatorial, and the 4-propionyloxy group is axial. The molecular structure is similar to that of racemic -prodine and the potent opioid agonist, ketobemidone. There is a hydrogen bond between N(1) ... O(1) 2.79 Å.     

Crystal structure of the low-temperature modification of α-RbB3O5

The crystal structure of α-RbB₃O₅ was refined by the Rietveld method with due regard for anisotropic vibrations of rubidium atoms to R _p = 2.93, R _wp = 3.80, R _B = 2.53, R _F = 2.84, and s = 1.54. The compound is isostructural to CsB₃O₅: it is orthorhombic, sp. gr. P2₁2₁2₁, a = 8.209(1), b = 10.092(1), c = 5.382(1) Å, and V = 445.9 Å 3. The framework structure is formed by the boron-oxygen [B ₂ ^III B^IVO₅] ^? rings consisting of two [BO₃]-triangles and a [BO₄]-tetrahedron. The rings are linked to form systems of helical chains running along the twofold screw axes parallel 2₁ to the a-and b-axes and infinite channels parallel to the a-and c-axes, which accommodate Rb atoms. The data were collected on an ADP-2 diffractometer [CuK _α radiation, Ni-filter, 12.00° < 2θ < 110.00°, a step in 2θ equal to 0.02°, count time 8 s per step, and 711 reflections α₁ + α₂)]. All the calculations were performed using version 3.3 of the WYRIET program. The comparison of the structures of α-and β-RbB₃O₅ and CsB₃O₅ revealed that the type of deformations in the framework structures of alkali-metal borates due to the changes of the temperature or the substitution of cations is determined by the role played by metal atoms, and especially, by large and heavy ions.     

Crystal and molecular structure of the (−)-N-hydroxyimide of (10-pinene-2-yl) succinimic acid

Two independent molecules in the unit cell are the same enantiomer of the title compound but possess slightly different conformations. Both conformers are joined by H-bonds to one water molecule. The configuration at C11 was established asR.Crystal data: C₁₄H₁₉O₃N×1/2H₂O; trigonal,P3₂;a=17.486(2),b=17.486(2),c=8.024(1)Å;V=2124.72(6)ų;Z=6; (CuK)=1.54178 Å;F(000)=834; finalR=0.0495 for 2376 reflections (of 2747 unique data).     

Crystal structure of bis-N,N′-p-chlorosalicylideneamine-1,2-diaminobenzene

The crystal structure of the title compound, C₂₀H₁₄N₂O₂Cl₂, has been determined by single crystal X-ray diffraction techniques. It crystallizes in the orthorhombic system witha=7.532(3)Å,b=18.563(2)Å,c=25.089(3)Å, space groupPbca,V=3507.9(3)ų,Z=8,F(000)=1584.D _x =1.459 g cm^–3,M=385.3 a. m. u., (MoK)=0.7107 Å, =3.35 cm^–1,T=297°K,R=0.086,R _w =0.049 for 2119 unique diffractometer data. The molecules are linked by van der Waals forces.     

Structural regularities of helicoidally-like biopolymers in the framework of algebraic topology: II. α-Helix and DNA structures

The developed apparatus of the “structural application” of algebraic geometry and topology makes it possible to determine topologically stable helicoidally-like packings of polyhedra (clusters). A packing found is limited by a minimal surface with zero instability index; this surface is set by the Weierstrass representation and corresponds to the bifurcation point. The symmetries of the packings under consideration are determined by four-dimensional polyhedra (polytopes) from a closed sequence, which begins with diamondlike polytope {240}. One example of these packings is a packing of tetrahedra, which arises as a result of the multiplication of a peculiar starting aggregation of tetrahedra by a fractional 40/11 axis with an angle of helical rotation of 99°. The arrangement of atoms in particular positions of this starting aggregation allows one to obtain a model of the α-helix. This apparatus makes it possible to determine a priori the symmetry parameters of DNA double helices.     

Crystal structure of the addition compound of N,N′-bi(2-pyridylmethyl)-oxamide and complex of manganese with 1,10-phenanthroline

The structure of the addition compound, Mn(phen)₃(PMoxdH₂)(ClO₄)₂ was established by X-ray crystallography, where PMoxdH₂ is N,N-bi(2-pyridylmethyl)-oxamide. Six nitrogen atoms of the three 1,10-phenanthroline bind to the manganese ion and the oxygen atom of PMoxdH₂ is uncoordinated. The addition compound crystallizes in the monoclinic space group C2/c, with lattice parameters a = 23.780(6), b = 11.948(5), c = 18.466(6) Å, = 117.38(3)°, V = 4659(3) ų, and Z = 4.     

Crystal structure of methyl-3, 4-O-ethylidene-β-L- arabinopyranoside

The acid-catalyzed ethylidenation of several methyl pentopyranosides has been studied and syntheses of many cyclic alkyl orthoacetates from pentopyranosides have been reported. In a study of the scope and limitation of the reduction of sugar epoxides with diborane/sodium borohydride, methyl-4-O-acetyl-2,3-anhydro--L-lyxopyranoside was reduced, yielding two products: methyl-2,3-anhydro--L-lyxopyranoside and methyl-3,4-O-ethylidene--L-arabinopyranoside. The latter product was characterized by X-ray diffraction and its structure indicates that the epoxide was not reduced as expected; rather, the epoxide was opened by the hydroxyl group of the reduced acetyl. Crystals of the title compound are monoclinic, space group P2₁ with the following cell dimensions: a = 5.818(l) Å, b = 10.842(2) Å, c =7.251(1) Å, = 91.47(1)°, Z = 2. Complete three-dimensional data (2_max = 150° for Cu K) were collected on a CAD-4 diffractometer by the –2 scan method. The structure was solved by the application of direct methods and refined by full-matrix least-square methods to a final reliability index of 0.04 for the observed 1031 reflections (I 3). The ethylidene ring has a twist conformation with a torsion angle of –42.8° about the C4–O bond. The pyranose ring is in a flattened chair conformation with the C2–C3–C4–C5 torsion angle of 33.5°. Of the acetal bond lengths, the C5–O5 length, (1.423 Å) is shorter than the values found in other methyl pyranosides. O2–H is involved in a bifurcated hydrogen bond intramolecularly to O1 and intermolecularly to O4.     

Crystal structure of an analog of the anticonvulsant lamotrigine, 3,5-diamino-6-(2,3,5-trichlorophenyl)-1,2,4-triazine·dimethanolate, and structure comparisons with related analogs

The compound 3,5-diamino-6-(2,3,5-trichlorophenyl)-1,2,4-triazine crystallizes with two methanol solvent molecules in the triclinic space group P1¯, with a = 7.372(4), b = 10.476(4), c = 11.863(11) Å, = 72.18(5), = 79.73(6), = 79.47(4)°. There is substantial distortion between the phenyl and triazine rings as illustrated by the value of the nonbonded angle C3t—C6t—C4 of 173.60° and the C4 atom being –0.4487 Å from the plane calculated for the triazine ring atoms. The lengths of the bonds of the triazine moiety suggest that there is a potential decrease in the degree of aromaticity of the ring. Comparisons are made between this structure, and other lamotrigine analog structures that have been reported.     

Crystal structure ofcatena-O,O′-diethylphosphonoacetatotriphenyltin

Triphenyltin diethylphosphonoacetate, which crystallizes in the monoclinc space groupP2₁/c (a=15.154(4),b=9.159(3),c=17.685(4) Å, =91.410(8)°), adopts a polymeric structure in which planar triphenyltin cations (_C—Sn—C=357.3(6)°) are axially linked by the diethylphosphonoacetato anions (Sn–O_esteryl=2.129(3), SnO_phosphoryl=2.420(3) Å; O–SnO=171.9(1)° into chains that propagate by translations along theb-axis. The structure has been erfined toR=0.037 for 3384I3(I) reflections.     

The interatomic vector’s method,algorithms, and programs for the solution of atomic structure of nanoclusters in crystal

A calculation technique and corresponding algorithms have been developed using the formalism of Fourier transform of finite functions. A software package for obtaining distributions of cluster interatomic vectors from diffuse X-ray scattering has been written and debugged. The programs were checked on a 30-atom cluster [CdTb₃F₂₆]. The attempts to obtain experimental data on a single crystal with nanoclusters using an Xcalibur S diffractometer (Oxford Diffraction) with a coordinate CCD detector were no success. The standard diffractometer software contains errors that lead to incorrect results upon the reconstruction of the distribution of diffuse scattering from different runs. These errors are of little importance when Bragg peaks are processed.     

Crystal and molecular structure of 3,5-cycloandrostan-6β-ol-17-one

The crystal and molecular structure of 3,5-cycloandrostan-6-ol-17-one has been determined by X-ray analysis,¹³C-NMR,¹H-NMR, IR and elemental analyses. The compound was obtained from dehydroepiandrosterone (DHEA) via the 3-tosyl derivative by refluxing in a butan-2-one/water mixture. The X-ray analysis shows that the planar cyclopropane ring is predominantly orientated and the formation of the C(3)-C(5) bond enables the A ring to adopt a distorted boat conformation. Spectroscopic evidence for the presence of the cyclopropane ring and the 6-hydroxy group are presented.     

Crystal and molecular structure of calcium L(–)-malate trihydrate

The new crystal and molecular structures of a less common hydrated calcium L(–)-malate (calcium (2S) 2-hydroxybutanedioate trihydrate) Ca(C₄H₄O₅)3H₂O, are reported. X-ray crystallographic data are as follows: a = 6.6460(3) Å, b = 8.3795(3) Å, c = 8.2707(4) Å, = 112.640(2)°, V = 425.1(4) ų, space group P2₁ (No. 4), Z = 2, D _calc = 1.767 g cm^–3. The calcium ion coordination number is seven. One of the three water molecules present in the unit cell is less strongly bound, only interacting with a calcium ion. In aqueous or hydroalcoholic solution, both di- and trihydrated species crystallize simultaneously.     

Phase transformation regularities of Zn in the solution systems by solid–liquid reaction milling

Zn powders were milled by stainless steel balls in the aqueous solution whose PH value were adjusted to 3, 7, and 11, respectively. Zn(OH)₂ and ZnO powders could be synthesized via this novel solid–liquid ball milling method. The compositions and the microstructures of the as-milled products were characterized by X-ray diffraction and SEM, respectively. The experimental results showed that the higher PH value is helpful to accelerate the reaction between Zn and H₂O. ZnO is the preferential product in the neutral and alkaline solutions. As a preferential product, a large number of ZnO could be obtained in the neutral and alkaline solutions after reaction. Finally, the phase transformation regularities of the as-milled products were also discussed.     

Crystal structure of 5α-cholest-6-one

The crystal and molecular structure of the steroid 5α-cholest-6-one has been determined by X-ray diffraction analysis. The compound crystallizes in space group P2₁ with the unit cell parameters a = 10.575(1) Å, b = 7.698(1) Å, c = 15.284(2) Å, β= 99.34(1)°, V = 1227.72 ų, Z = 2, and R = 0.054 for 1634 observed reflections. The six-membered rings (A, B, and C) have the chair conformations, whereas the five-membered ring Dis intermediate between 13β-envelope and 13β-14α half-chair. All the rings of the steroid skeleton are trans connected. The molecules are linked together by the intermolecular C-H?O hydrogen bonds.     

Crystal and molecular structure of β-resorcylidene aminoguanidine copper(II) complex

The tridentate Schiff base, -resorcylidene aminoguanidine (RAG)1 was synthesized from 2,4-dihydroxybenzaldehyde and aminoguanidine and complexed with copper(II) to form a copper(II)--resorcylidene aminoguanidine (Cu-RAG)2 complex. X-ray diffraction analysis of compound2 (orthorhombic, Pnma,a=11.674(1);b=6.7198(7);c=17.836(2) ) revealed a square-planar copper(II) cation with a tridentate·ligand bound through two nitrogen atoms (N1 and N3) of the aminoguanidine moiety and an oxygen (O1) of the monodeprotonated dihydroxybenzaldehyde function. The remaining coordination site was occupied by chloride and the structure was rigidly planar as demanded by the restrictions of the crystallographic space group. The unit cell contents exhibited an extended sheet-like structure constructed via hydrogen bonds both intermolecularly and involving two water molecules (O3 and O4) also restricted by the same mirror symmetry. The remaining water (O5) provided for interlayer hydrogen bonding.     

Crystal and molecular structure of 12α-hydroxy-ent-kaur-16-en-19-oic acid

The crystal and molecular structure of the title compound has been determined by X-ray crystallographic analysis. The 12-hydroxy-ent-kaur-16-en-19-oic acid previously isolated from other sources is found for the first time in a species of theMachaeranthera genus. The unit cell contains three closely similar independent molecules organized into trimers.