Crystalline Behavior and Structure of a Liquid Crystal Compound, 5‐{[4′‐(((Pentyl)oxy)‐4‐biphenylyl)carbonyl]oxy}‐1‐pentyne

Single crystals of two liquid crystal compounds, 5‐{[4′‐(((pentyl)oxy)‐4‐biphenylyl)carbonyl]oxy}‐1‐pentyne (A3EO5) and 5‐{[(4′‐nonyloxy‐4‐biphenylyl)carbonyl]oxy}‐1‐pentyne (A3EO9), have been prepared by solution growth technique. The morphologies and structures of A3EO5 and A3EO9 crystals were investigated by wide angle X‐ray diffraction (WXRD), atom force microscope (AFM) and transmission electron microscope (TEM). In contrast to the same series of compounds which have a longer alkyl tail, 5‐{[(4′‐heptoxy‐4‐biphenylyl)carbonyl]oxy}‐1‐pentyne (A3EO7), 5‐{[(4′‐heptoxy‐4‐biphenylyl)oxy]carbonyl}‐1‐pentyne (A3E′O7) and A3EO9, A3EO5 shows strikingly different crystalline behavior. The former three compounds have only one crystal form, whereas A3EO5 exhibits polymorphism. Specifically, A3EO5 crystals grown from toluene solution show two crystal forms. The first one is crystal I which adopts a monoclinic P112/m space group with unit cell parameters of a?5.79 Å, b?8.34 Å, c?43.92 Å, γ?96°, and the other one is crystal II which adopts a monoclinic P112 space group with unit cell parameters of a?5.55 Å, b?7.38 Å, c?31.75 Å, γ?94°. When using dioxane as the solvent to grow A3EO5 crystal, we can selectively obtain crystal I. A3EO5 melt‐grown crystals also have two crystal forms which derive from crystal I and crystal II, respectively. The different crystalline behavior of the compounds should correlate with their different electron dipole moment resulting from the different length of alkyl tail.     

Titanium‐Catalyzed Norbornene Oligomerization. Isolation of a Crystalline Heptamer with a 2,3‐exo‐Disyndiotactic Structure

Summary: Norbornene (NB) was oligomerized at 0 °C using AlEt₂Cl‐TiCl₄ at a monomer/titanium molar ratio of about 11. The oligomerization product consists of a fraction soluble in diethyl ether, amorphous by X‐ray examination, and of a crystalline fraction, insoluble in diethyl ether. The crystalline fraction was shown by powder X‐ray diffraction to consist of a NB heptamer. Single‐crystal X‐ray analysis indicated that the heptamer had a stereoregular 2,3‐exo‐disyndiotactic structure. The heptamer adopts a strained, highly irregular, folded conformation in the crystalline state. Structural differences with respect to NB oligomers obtained with zirconocene catalysts are discussed.

A view of the molecular structure of the crystalline NB heptamer.     

Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. 63. Darstellung und Kristallstruktur von Tetramethyltitan-tetrahydrofuran

Contributions to the Chemistry of Transition Metal Alkyl Compounds. 63. Preparation and Crystal Structure of Tetramethyltitanium Tetrahydrofuran Me₄Ti · 2THF 1 dissoziates partially in n-pentane. The formed Me₄Ti · THF 2 could be isolated. According to X-ray structure determination the molecules of 2 have a trigonalbipyramidal shape with the THF molecule in axial position.     

Zwei Tetrachlorothiotantalate: [Na‐15‐Krone‐5][TaSCl4 · Dioxan] und [Na‐15‐Krone‐5]2[(TaSCl4)2Dioxan] · S8

Two Tetrachlorothiotantalates: [Na‐15‐crown‐5][TaSCl₄ · dioxane] and [Na‐15‐crown‐5]₂[(TaSCl₄)₂dioxane] · S₈ During the reaction of Na₂S₄, TaCl₅ and 15‐crown‐5 in dichloromethane the crown ether partly suffers degradation to 1,4‐dioxane. Aside from sulfur, [Na‐15‐crown‐5][TaSCl₄ · dioxane] was the first product obtained. It crystallizes in the monoclinic space group P2₁/n with a = 1066.1, b = 1781.3, c = 1258.3 pm, β = 97.14°, Z = 4. In the [TaSCl₄ · dioxane]^– ion a dioxane molecule is loosely bonded to a square‐pyramidal TaSCl₄^– unit; two chlorine atoms are in contact with an Na⁺ ion. Upon standing with the mother liquor [Na‐15‐crown‐5]₂[(TaSCl₄)₂dioxane] · S₈ was formed. It crystallizes in the monoclinic space group C2/m; a = 1768.5, b = 1084.0, c = 1517.3 pm, β = 118.46°, Z = 4. In this case a dioxane molecule is coordinated with two TaSCl₄^– units. The [(TaSCl₄)₂ · dioxane]^2– ions and S₈ molecules alternate in the stacking direction b.     

Crystal Structures,Bonding and Electronic Structures of MM′As,a Series of New Ternary Arsenides (M = Zr,Hf; M′ = Fe,Co, Ni)

All six new arsenides were prepared by arc-melting of preheated mixtures of the monoarsenides MAs with the 3d metals Fe, Co, and Ni, respectively. The isostructural title compounds all form the Co₂Si structure type, in contrast to the corresponding phosphides with ZrNiP occurring in the Ni₂In type. The anomalous expansions of the unit cells from ZrCoAs to ZrNiAs (V = 178.5(3) ų versus V = 182.5(1) ų) and from HfCoAs to HfNiAs (V = 175.03(5) ų versus V = 177.0(1) ų) can be understood based on Extended Hückel calculations of the electronic structure of HfCoAs.     

Strukturen ladungsgestörter oder räumlich überfüllter Moleküle. 15. Tetracyanethen-Natrium-Dimethoxyethan

Structures of Charge-Perturbed or Sterically Overcrowded Molecules. 16. Tetracyanoethylene Sodium Dimethoxyethane The Single crystal structure of [(NC)₂C? C(CN)₂?·Na⊕(H₃CO? CH₂CH₂? OCH₃)]∞ reveals two formula units within the triclinic (P1 ) unit cell. The tetracyanoethylene radical anions are arranged along parallel double layers, which are shifted relative to each other, and in between which are interspersed the sodium counter cations and their dimethoxyethane ligands. The distances within the double layers amount to 300 pm and the ones between them to 385 pm. The six-fold coordinated Na⊕ centers are surrounded by four radical anions with contact distances Na…?N between 250 and 254 pm as well as by a twofold solvent ligand with Na…?O of 238 and 241 pm. Due to the electron transfer to the acceptor molecule, its (NC)₂C-halves twist by 8° and the bond lengths of the N?C? C subunits, bent by each 3°, are shortened up to 2 pm. The structural parameters are compared to those of the analogous potassium salt [TCNE^?K^⊕DME], of the dianion , of the sodium salts [(NC)₃C^?Na^⊕]∞ as well as [(NC)₂C? C(CHCH)₂? C(CN)₂^?Na^⊕]_∞ and, in addition, are discussed based on geometry-optimized MNDO calculations.     

Synthese und Einkristallstrukturanalyse von Bis(benzyltrimethylammonium)fullerid-Ammoniakat; (BzlNMe3)2C60 · 3 NH3

Synthesis and Single Crystal Structure Analysis of Bis(benzyltrimethylammonium)fulleride Ammonia 1/3, (BzlNMe₃)₂C₆₀ · 3 NH₃ The title compound has been prepared from K₂C₆₀ by ion exchange of potassium for benzyltrimethylammonium cations in liquid ammonia. X-ray single crystal structure analysis reveals highly ordered fulleride ions forming a layer-like arrangement with short inter-fullerene distances. The anionic fulleride layers are separated by layers of benzyltrimethylammonium cations and ammonia.     

Strukturen sterisch überfüllter oder ladungsgestörter Moleküle. 9. Tetracyanethen-Kalium-Dimethoxyethan

Structures of Sterically Overcrowded or Charge Perturbed Molecules. 9. Tetracyanoethylene Potassium Dimethoxyethane The single crystal structure of [(NC)₂C?C(CN)₂ ^?K^⊕(H₃CO? CH₂CH₂? OCH₃)] reveals 4 formula units per monoclinic (P2₁/n) unit cell. The tetracyanoethylene radical anions are stapled within slightly undulated layers exhibiting alternating average intermolecular distances of 315 pm and 360 pm between their central C?C bonds. In- between the closer layers both are interspersed the eight-fold coordinated K^⊕ counter cations and the solvating dimethoxyethane molecules with contact distances K^⊕…?N of 282 to 306 pm and K^⊕…?O of 279 to 294 pm. The molecular halves of the radical anions (NC)₂C?C(CN)₂^? are twisted by 12° and the C?C, C? C and C?N bond length amount to 142, 142, and 114 pm, respectively. These structural features are discussed by comparison with those of analogous cyanohydrocarbon salts, with those of the neutral molecule, its largely interaction-free anion and its dianion as well as with results of geometry-optimized MNDO calculations.     

Growth of Shape‐ and Size‐Selective Zinc Oxide Nanorods by a Microwave‐Assisted Chemical Bath Deposition Method: Effect on Photocatalysis Properties

Herein, we demonstrate the shape‐ and size‐selective growth of ZnO nanostructures on indium tin oxide‐coated glass substrates by using a microwave‐assisted chemical bath deposition method. By systematically controlling the deposition parameters, it is possible to produce shape‐ and size‐selective nanostructures with high alignment and uniformity. Specifically, the pH of the bath can be used to control the shape of rods from bundled structures to tapered and flat tips. Furthermore, the deposition temperature can be used to control the size of the ZnO array from 770 to 125 nm. The prepared rods were active catalysts in the degradation of methylene blue under UV radiation, and exhibited size‐dependent activity.     

catena‐Poly[[di‐μ2‐aqua‐hexaaquabis(μ3‐4‐oxidopyridine‐2,6‐dicarboxylato)trimanganese(II)] trihydrate]: a new one‐dimensional coordination polymer based on a trinuclear MnII complex of chelidamic acid

4‐Hydroxypyridine‐2,6‐dicarboxylic acid (chelidamic acid, hypydc_[H]H₂) reacts with MnCl₂·2H₂O in the presence of piperazine in water to afford the title complex, {[Mn₃(C₇H₂NO₅)₂(H₂O)₈]·3H₂O}_n or {[Mn₃(hypydc)₂(H₂O)₈]·3H₂O}_n. This compound is a one‐dimensional coordination polymer, with the twofold symmetric repeat unit containing three metal centres. Two different coordination geometries are observed for the two independent Mn^II metal centres, viz. a distorted pentagonal bipyramid and a distorted octahedron. The 4‐oxidopyridine‐2,6‐dicarboxylate anions and two of the water molecules act as bridging ligands. The zigzag‐like geometry of the coordination polymer is stabilized by hydrogen bonds. O—H...O and C—H...O hydrogen bonds and water clusters consolidate the three‐dimensional network structure.     

Tetraphenylphosphonium-trichloroplumbat(II), PPh4PbCl3 · CH3CN

Tetraphenylphosphonium Trichloroplumbate(II), PPh₄PbCl₃ · CH₃CN PPh₄PbCl₃ · CH₃CN was obtained by reaction of PbCl₂ and PPh₄Cl in acetonitrile. It was also formed along with (PPh₄)₂Se₂Cl₆ when PbSe was treated with chlorine in the presence of PPh₄Cl. Its crystal structure was determined by X-ray diffraction (R = 0.029 for 4186 reflections). The triclinic crystals contain PbCl₃^– ions that are associated to polymer chains. Each Pb atom has distorted square pyramidal coordination; the pyramids share two opposite basal edges. The chloro bridges are rather asymmetrical.     

Phase transition of Fe(dpm)<Subscript>3</Subscript> in the range 243–210 K

The volatile Fe(dpm)₃ complex was studied by X-ray diffraction at 243 K and 210 K. A phase transition from monoclinic to triclinic structure was found in the temperature range 236–226 K. The packing of complexes in the structures is analyzed by the procedure of translation sublattice isolation. The motif of mutual arrangement of Fe atoms is pseudohexagonal in both modifications. Apart from the differences in the Fe...Fe distances, there are differences in rotation of definite chelate rings.     

Replacement of Fe atoms by Ru in a carbidocarbonyl cluster [Fe<Subscript>6</Subscript>C(CO)<Subscript>16</Subscript>]<Superscript>2−</Superscript>. Structures of reaction products

The reaction of the carbidocarbonyl cluster [Fe₆C(CO)₁₆]²⁻ with ruthenium(IV) hydroxochloride Ru(OH)Cl₃ was studied. At 90–100 °C, the reaction gave products of replacement of Fe atoms by Ru in the [Fe₆C(CO)₁₆]²⁻ cluster along with degradation products. Treatment of the replacement products with FeCl₃ afforded the [Fe_2.96Ru_3.04C(CO)₁₇] compound (1), which was characterized by X-ray diffraction analysis. The crystals of cluster 1 are composed of two types of octahedral molecules (1a and 1b) in a ratio of 2 : 1. Molecules 1a are in general positions, and molecules 1b are located on twofold axes. In both molecules, the Fe and Ru atoms are disordered over four of six positions. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1761–1766, August, 2005.     

Zur Chemie des Dimesityleisens. VIII. Lösungsverhalten von Tetramesityldieisen und die Kristallstruktur eines Dimethoxyethan-Addukts

Chemistry of Dimesityl Iron. VIII Solution Behaviour of Tetramesityldiiron and Crystal Structure of Dimesityl(dimethoxyethane)iron The dimer dimesityliron yields in polar solvents solvated monomers. The adduct with dimethoxyethane was isolated and characterized by X-ray structure determination.     

Crystal structure of 5,6‐bis(9H‐carbazol‐9‐yl)benzo[c][1,2,5]thiadiazole: distortion from a hypothetical higher‐symmetry structure

Nucleophilic substitution of F atoms in 5,6‐difluorobenzo[c ][1,2,5]thiadiazole (DFBT) for carbazole could be potentially interesting as a novel way of synthesizing building blocks for new conjugated materials for applications in organic chemistry. The crystal structures of 5,6‐bis(9H‐carbazol‐9‐yl)benzo[c ][1,2,5]thiadiazole (DCBT), C₃₀H₁₈N₄S, and its hydrate, C₃₀H₁₈N₄S·0.125H₂O, were investigated using single‐crystal X‐ray analysis. The hydrate contains two symmetry‐independent DCBT molecules. The dihedral angles between the plane of the central benzothiadiazole fragment and that of the carbazole units vary between 50.8 and 69.9°, indicating conformational flexibility of the DCBT molecule in the crystals, which is consistent with quantum chemical calculations. The analysis of the crystal packing of DCBT revealed that the experimental triclinic structure could be described as a distortion from a hypothetical higher‐symmetry monoclinic structure. The quantum chemical calculations of two possible monoclinic structures, which are related to the experimental structure by a shifting of molecular layers, showed that the proposed structures are higher in energy by 5.4 and 10.1 kcal mol⁻¹. This energy increase is caused by less dense crystal packings of the symmetric structures, which results in a decrease of the number of intermolecular interactions.     

Synthesis and Characterization of Ferrocene—Containing Liquid Crystalline Materials with a Bromo—phenyl Moiety

Ten ferrocene-containing liquid crystalline materials,pFcC6H4CO2C6H4N-CHC6H4O2CC6H3BrOCnH2n 1(type I)and p-FcC6H4N=CHC6H4O2CC6H3BrOCnH2n 1(type II),were synthesized by condensation reactions of two ferrocenesubstituted amines,p-FcC6H4CO2C6H4NH2(4)and pFcC6H4NH2(5)(Fc:ferrocenyl)with five bromo-substituted benzaldehydes(3)(H2n 1CnOC6H3BrCOOC6H4CHO,n=2,4,6,8and 10).Their mesogenic behaviors were studied by hot-stage polarized optical microscopy and differential scanning calorimetry,The effects of structure(rigid core,terminal chain length)on the phase transition behaviors were discussed.     

5‐Iodouracil: structure of a reflection twin

The crystal structure of 5‐iodouracil, C₄H₃IN₂O₂, has been determined in the noncentrosymmetric space group P2₁ on a nonmerohedrally twinned crystal. Both twin components are enantiomorphically pure, but the twin element is a mirror plane perpendicular to c*. The molecular structure is discussed and stacking faults in the two‐dimensional packing are proposed as a reason for the twinning.