The crystal and molecular structure of ferricinium tetrachloroferrate

The crystal and molecular structure of ferricinium tetrachloroferrate was studied by X-ray diffraction. The compound crystallizes in space group Pna2₁ with 4 molecules C₁₀H₁₀Cl₄Fe₂ per unit cell. Data analysis was relatively difficult and direct methods of phase determination were very useful in the interpretation of the Patterson synthesis. The two rings in ferricinium are nearly parallel. The structural parameters are very similar to those previously published by others for ferrocene. This molecular structure and its vibrational properties seem to be in contrast to a general rule previously formulated by others for the infrared spectra of cyclopentadienyl compounds.     

Four-center-type photopolymerization in the crystalline state. XI. Crystal structure of p-phenylenediacrylic acid diethyl ester above the crystal transition point

The crystal structure of p-phenylenediacrylic acid diethyl ester above the transition point was determined at 70°C by x-ray diffraction. No significant differences in molecular arrangement are found between the structures of the α₂ form (above the transition point) and the α₁ form (at room temperature). Since the α₁ form is photopolymerized, it is concluded that selective dimerization in the α₂ form results not form the crystal structure of the monomer, but from the deterioration of molecular arrangement by the formation of dimer.     

The crystal and molecular structure of 1,1,2,4,4,5-hexaphenyl-1,4-diphosphoniacyclohexadiene-2,5 dibromide

The crystal and molecular structure of 1,1,2,4,4,5-hexaphenyl-1,4-diphosphoniacyclohexadiene-2,5 dibromide has been determined by a single crystal, x-ray diffraction study using diffractometer data. The compound crystallizes in the space group P2₁/_c with unit cell constants a = 8.813(1), b = 36.736(4), c = 12.478(1) Å, and β = 120.91°(1). The structure was solved by the heavy atom method and refined by block-diagonal least-squares to a final R = 0.04 for the 2761 statistically significant reflections. The structure determination shows that the central phosphonium ring is a diene and not a delocalized structure as anticipated. The ring is in the boat conformation with the axial phenyl rings aligned essentially parallel to each other and 3.55 Å apart.     

The crystal and molecular structure of |2-keto-|7-deoxo-8-azacstrone methyl ether hydrohromide

The crystal and molecular structure of 12-keto-17-deoxo-8-azaeslrone methyl ether hydro-bromide (C₁₈H₂₄BrNO₂) has been determined by a single crystal, x-ray diffraction study. The compound crystallizes in the monoclinie space group P2₁/n with unit cell constants a = 12.024 (2), b = 10.340 (1), c = 14.269 Å (2), β = 104.12° (1). The structure was solved by the heavy atom method and refined by block-diagonal least-squares to a final R-value = 0.03₆ for the 8.35 independently measured, statistically significant reflections. All hydrogen atoms, including methyl hydrogens, were located.     

Biotransformation,spectroscopic investigation,crystal structure and electrostatic properties of 3,7α‐dihydroxyestra‐1,3,5(10)‐trien‐17‐one monohydrate studied using transferred electron‐density parameters

The biologically transformed product of estradiol valerate, namely 3,7α‐dihydroxyestra‐1,3,5(10)‐trien‐17‐one monohydrate, C₁₈H₂₂O₃·H₂O, has been investigated using UV–Vis, IR, ¹H and ¹³C NMR spectroscopic techniques, as well as by mass spectrometric analysis. Its crystal structure was determined using single‐crystal X‐ray diffraction based on data collected at 100 K. The structure was refined using the independent atom model (IAM) and the transferred electron‐density parameters from the ELMAM2 database. The structure is stabilized by a network of hydrogen bonds and van der Waals interactions. The topology of the hydrogen bonds has been analyzed by the Bader theory of `Atoms in Molecules' framework. The molecular electrostatic potential for the transferred multipolar atom model reveals an asymmetric character of the charge distribution across the molecule due to a substantial charge delocalization within the molecule. The molecular dipole moment was also calculated, which shows that the molecule has a strongly polar character.     

Molecular and crystal structure of a cationic dinitrosyl iron complex with 1,3-dimethylthiourea

A new dinitrosyl iron complex of the composition [Fe(SC(NHCH₃)₂)₂(NO)₂]Cl (I) is obtained by direct nitrosylation of ferrous sulfate and a hydrochloric acid solution of 1,3-dimethylthiourea. The characteristic features of the molecular and crystal structure of complex I is determined by single crystal X-ray diffraction analysis.     

The crystal and molecular structure of 6-oxadihydrouracil

The crystal and molecular structure of 6-oxadihydrouracil (C₃H₄N₂O₃) has been determined by single crystal x-ray diffraction techniques. The compound crystallizes in the space group P2₁ 2₁ 2₁ with four molecules in a unit cell of dimensions: a = 5.106(1)Å, b = 12.461(2)Å and c = 7.112(1)Å. The structure was solved by direct methods and refined to a final value of R = 0.052. The oxauracil ring is non-planar with the C5 atom assuming tetrahedral geometry and the ring oxygen having oxazinal distances and angle (C-O = 1.43₂Å, N-O = 1.40₈Å, and CON angle of 109.0°). The usual hydrogen bonding patterns associated with the uracil ring are absent in this compound.     

The crystal and molecular structure of an unusual49 heterocycle,62 2-thia-1,3,5-triaza-7-phosphaadamantane 2,2-dioxide51

The crystal and molecular structure of 2-thia-1,3,5-triaza-7-phosphaadamantane 2,2-dioxide (C₅H₁₀SPO₂N₃) has been determined by single crystal x-ray diffraction techniques. The compound crystallizes in the space group P2₁/c with four formula weights per unit cell of dimensions a = 6.129 (1) Å, b = 12.440 (2) Å, c = 14.028 (2) Å, β = 127.31 (1)°. The structure was solved by direct methods and refined to a final value of R = 0.079.     

The crystal and molecular structure of 3,7-dicyano-3,5,7-triaza-1-phosphabicyclo[3.3.1]nonane

The crystal and molecular structure of the title compound has been determined by a single crystal x-ray diffraction study using counter-data. The compound crystallizes in the monoclinic space group, P2₁/c, with a = 8.657 ± .001Å, b = 10.513 ± .001Å, c = 10.378 ± .001Å, β = 99.68 ± .01° for Z = 4. The structure was solved by the symbolic addition procedure and refined by block-diagonal least-squares to R = 0.052 for 1479 statistically significant reflections. The geometry of the bicyclic ring system is discussed.     

Molecular and crystal structure of 4,6,6-trimethyl-2-oxo-5,6-dihydro-2H-pyran-3-carbonitrile and 4,6,6-trimethyl-2-oxo-1,2,5,6-tetrahydropyridine-3-carbonitrile

Single crystals of 4,6,6-trimethyl-2-oxo-5,6-dihydro-2H-pyran-3-carbonitrile and 4,6,6-trimethyl-2-oxo-1,2,5,6-tetrahydropyridine-3-carbonitrile were prepared and submitted to X-ray diffraction analysis. Both compounds have a molecular structure belonging to the C₁ symmetry group. The heterocyclic rings are in a distorted envelope conformation. The crystals belong to the monoclinic system and each contain four molecules in the unit cell. In the crystal the pyridine derivative exists in the form of centrosymmetric dimers stabilized by intermolecular hydrogen bonds between the oxygen atoms of the carbonyl group and the hydrogen atom at the nitrogen atom of the ring. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1620–1624, November, 2007.     

A variable temperature study of Ru3(CO)12 in the solid state and the generation of alternative crystal structures

Summary The molecular and crystal structure of Ru₃(CO)₁₂ has been reinvestigated on single-crystal X-ray diffraction data collected at 100 and 150 K. Thermal motion analysis on high-order diffraction data have been used to characterize the motion about equilibrium positions of the molecule as a whole and of groups of atoms. It has been shown that, while the molecule undergoes an almost isotropic rigid-body librational and translational motion, the three Ru(CO)₄ units undergo different librational motions about the axes passing between each Ru atom and bisecting the opposite 615-01 bond. Packing potential energy calculations and computer graphics have been used to show that the most favoured packing motif in the experimental crystal is based on interlocking between tetracarbonyl units formed by two pairs of CO ligands at right angles along a 615-02 edge. Starting from the structure of Ru₃(CO)₁₂, alternative crystal arrangements have been generated and compared with the experimental crystal structure in terms of packing efficiency and cohesive energy.     

Acetic anhydride at 100 K: the first crystal structure determination

Acetic anhydride (ethanoic anhydride), (CH₃CO)₂O, is a widely used acetylation reagent in organic synthesis. The crystal and molecular structure, as determined by single‐crystal X‐ray analysis at 100 K, is reported for the first time. A crystal of the title compound (m.p. 200 K) suitable for X‐ray diffraction was grown from the melt at low temperature. The title compound crystallizes in the orthorhombic space group Pbcn, with Z = 4. In the crystal, the molecule adopts an exact C₂‐symmetric conformation about a crystallographic twofold axis. The molecules are densely packed. Two of the methyl H atoms form short intermolecular contacts to a neighbouring carbonyl O atom, which can be viewed as weak hydrogen bonds.     

Synthesis, crystal structure and thermal decomposition of a new copper propionate [Cu(CH3CH2COO)2]·2H2O

A new copper propionate complex was synthesised and characterized for application as precursor for CuO based oxide thin films deposition. The FT-IR and X-ray diffraction analyses have revealed the formation of a cooper propionate complex [Cu(CH₃CH₂COO)₂]·2H₂O. The crystal and molecular structure of a new copper propionate complex was determined by XRD on the copper propionate single crystal. The copper propionate complex has a binuclear structure, connected by bridging bidentate carboxylates groups and a Cu?Cu bond of 2.6 Å. The thermal decomposition of copper propionate has been investigated by thermal analysis using thermogravimetric (TG) and differential thermal analysis (DTA), differential thermal analysis coupled with quadrupole mass spectrometry-QMS, X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR) techniques. TG and XRD data indicate the reduction of Cu(II)-Cu(I,0) during the decomposition of copper propionate.     

Copper(II) complex based on a V-shaped ligand, 2,6- bis (2-benzimidazolyl)pyridine: synthesis,crystal structure,DNA-binding properties,and antioxidant activities

A copper(II) complex based on a V-shaped ligand, 2,6-bis(2-benzimidazolyl)pyridine (bbp), has been synthesized and characterized by elemental analysis, molecular conductivity, ¹H NMR, IR, UV-Vis spectra, and X-ray single-crystal diffraction. The crystal structure of [Cu(bbp)₂](pic)₂?·?2DMF (pic?=?picrate) shows copper is six-coordinate forming a distorted octahedron. The interaction between Cu(II) complex and DNA was investigated by spectrophotometric methods and viscosity measurement. The experimental results suggest that the Cu(II) complex binds to DNA via intercalation. Antioxidant assay in vitro also shows that the Cu(II) complex possesses significant antioxidant activities.     

Investigations on the influence of the substrate on the crystal structure of sputtered LiCoO2

The influence of the uppermost substrate layer on the structural properties of sputtered lithium cobalt oxide (LiCoO₂) is discussed in this work. For this purpose, bare, oxidized, and platinum-coated silicon wafers, as well as stainless steel and titanium sheets, were used as substrates. The resulting crystal structure of LiCoO₂ deposited on these substrates was analyzed and discussed. The LiCoO₂ thin films were deposited by RF magnetron sputtering with different film thicknesses. A subsequent annealing step at 700 °C was performed to induce the crystallinity of LiCoO₂. The crystal orientation was determined by X-ray diffraction. The obtained results show a strong dependency of LiCoO₂'s crystal structure on the surface the film is deposited on. However, the strong influence of the film thickness reported in previous publications could not be observed. If LiCoO₂ is deposited on the substrates with a metallic surface, a strong (003) preferential orientation is obtained for a wide range of film thicknesses. In contrast, sputtering of LiCoO₂ on bare and on oxidized silicon wafers results in a (101) dominated crystal structure for the different film thicknesses. These experiments show the importance of the characterization of LiCoO₂'s crystal structure in the intended battery setup.     

Molecular and crystal structures of 5,7-dichloro-4-nitro-2,1,3-benzoxadiazole and products of its reactions with secondary amines

The molecular and crystal structures of 5,7-dichloro-4-nitro-2,1,3-benzoxadiazole and products of its reactions with hexamethyleneimine and dimethylamine were established by X-ray diffraction analysis. The molecular structures and the systems of hydrogen bonds in the crystals of these compounds are discussed.     

The absence of nitrone form in re-determined crystal structure of 2-hydroxyimino-3-methyl-4-nitro-2,5-dihydrothiophene 1,1-dioxide

Crystal and molecular structures of 2-hydroxyimino-3-methyl-4-nitro-2,5-dihydrothiophene-1,1-dioxide C₅H₆N₂O₅S (I) have been re-determined by single crystal X-ray diffraction analysis. The structure of I (space group P2₁2₁2₁, a = 6.124(1) Å, b = 9.205(2) Å, c = 14.884(3) Å, Z = 4) was solved by the direct method and refined anisotropically in the full-matrix approximation to R = 0.064 using all 1756 measured independent reflections (automated diffractometer CAD-4, λCuK_α, anomalous scattering taken into account). This study proves that the compound I contains a disordered group H-O-N=C, but not the isomeric nitrone group O←N(H)=C, as it has been concluded by the workers who pioneered single crystal X-ray diffraction study of I and erroneously took the second low-occupied oxygen position of the disordered hydroxyimine group for H at N atom.     

水杨醛缩2-芴胺席夫碱的合成、晶体结构及生物活性

芴在煤焦油中的含量为1%～2%,全国每年可从中提取1.4万吨芴.芴是一种带有荧光的片状化合物,作为一种新型的发光材料主要用于制备芴基金属化合物、有机光导体、树脂、染料、Ziegler-Natta催化剂的给电子体等.     

The crystal and molecular structure of 1,1,4,4-tetraphenyl-1,4-diphosphoniacyclohexane dibromide

The crystal and molecular structure of 1,1,4,4-tetraphenyl-1,4-diphosphoniacyclohexane dibromide has been determined by a single-crystal, x-ray diffraction study using diffractometer data. The compound crystallizes in the monoclinic space group P2₁/c with unit cell constants of a = 12.777(1), b = 26.180 (2), c = 16.283 (1) Å, and β = 91.18(1)°. The structure was solved by the heavy atom method with the 4176 independent and statistically significant structure factors refining to a value of R = 0.07. The diphosphonium ring is in the chair conformation with each phosphorus ion having an axial and equatorial phenyl ring attached. P-C and C-C bond lengths of 1.78 ± .03 Å and 1.53 ± .03 Å respectively agree well with the literature value for these distances.     

Langmuir-Blodgett films as aligning layers for homeotropic alignment of liquid crystal molecules

The first single crystal structure of a Group VA halide salt with three equivalent long n-alkyl chains, benzyltrioctadecylammonium bromide (BzN18Br), is reported. It consists of alternating interdigitated and non-interdigitated regions of alkyl chains separated by ionic planes. Two chains per molecule are paired and extend to one side in a non-interdigitated region. The third chain is on the opposite side of the ionic plane and pairs intermolecularly to form an adjacent, interdigitated region. The thickness of two nearly extended molecules defines the bilayer unit-two ionic planes flanked by a region with intramolecularly paired chains and separated by an interdigitated chain region. Powder X-ray diffraction and optical microscopy data of liquid crystalline BzN18Br are consistent with an enantiotropic smectic A₂ (SmA₂) phase: the three n-alkyl chains of each molecule are projected from one side of an ionic plane, and head groups of neighbouring molecules are oriented head-to-head, in a non-interdigitated bilayer assembly. The structure of BzN18Br fills an important gap in our knowledge about the crystal packing of ammonium and phosphonium salts with one-four equivalent long n-alkyl chains. A comparison of their packing arrangements is made and the transitional nature of the BzN18Br structures is demonstrated. Although salts with one, two, or three long n-alkyl chains form SmA₂ phases, each is distinctive in its molecular packing. A large molecular reorganization accompanies the crystal-to-liquid crystal transition of BzN18Br.