Stereochemistry of Polynuclear Cadmium(II)thioglycolates: Crystal Structure of [ICd8(SCH2CH2OH)12]3+ · 3I− · H2O

Crystals of the title compound are triclinic, a = 27.87 Å, b = 10.77 Å, c = 12.94 Å, α 73.1°, β 116.1°, γ 120.0°, space group P1 . The structure consists of octanuclear ions: Eight Cd(II) ions are found at the corners of a distorted cube, the center of the cube is occupied by an iodide, the twelve thioglycolate sulfur atoms bridge the twelve edges of the cube thereby forming a distorted icosahedron. Cadmium ions are either five or seven coordinate. The phase problem for this structure was solved using a combination of very high and very low E-values.     

Crystalline structure and morphology of biaxially oriented polyamide‐11 films

The effect of the uniaxial and biaxial stretching and subsequent solution annealing of extrusion‐cast polyamide‐11 films on the crystalline structure and morphology was investigated with differential scanning calorimetry, wide‐angle X‐ray diffraction (WAXD), Fourier transform infrared spectroscopy, and small‐angle X‐ray scattering (SAXS). The extrusion‐cast polyamide‐11 films exhibited elevations in the glass‐transition and cold‐crystallization temperatures with a constant crystallinity and a constant melting point during aging under room conditions (20–26 °C and 20–31% relative humidity). WAXD and SAXS suggested that chain‐folded lamellae of coexisting α‐ and β‐crystals existed in all the stretched polyamide‐11 films. WAXD pole figures indicated that hydrogen bonds in the hydrogen‐bonded sheets of these two crystalline forms apparently formed between antiparallel chain molecules. The unit cell parameters [a = 9.52 Å, b = 5.35 Å, c = 14.90 Å (chain axis), α = 48.5°, β = 90°, and γ = 74.7° for a triclinic α form and a = 9.52 Å, b = 14.90 Å (chain axis), c = 4.00 Å, α = 90°, β = 67.5°, and γ = 90° for a monoclinic β form] for polyamide‐11 crystals were proposed according to the results of this study and the results of previous investigators. The unit cell parameters of the stretched extrusion‐cast polyamide‐11 films varied, depending on the stretching conditions (the stretch temperature and stretch ratio). As the stretch temperature and stretch ratio were increased, the crystal became more similar to the form described previously and was accompanied by an increase in the long spacing of crystalline lamellae. Annealing the stretched films in a boiling 20% formic acid solution made slightly more perfected crystals. The hydrogen‐bonding α(010) + β(002) planes, which are nearly parallel to both amide group planes and zigzag methylene sequence planes of the biaxially stretched films were found to be parallel to the film surface. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2624–2640, 2002     

The Crystal and Molecular Structure of rac-15-cyano-1,2,2,7,7,12,12-heptamethyl corrin hydrochloride,metal free corrin

The crystal structure of a metal free corrin hydrochloride synthesised by Eschenmoser & Fischli has been found by X-ray analysis. The crystals are monoclinic and contain ethanol of crystallisation; a = 10.84 Å, b = 12.04 Å, c = 26.04 Å, γ = 120.4 in space group P2₁/a. The structure was determined by direct methods and refined to R = 0.076 for 3252 statistically significant reflections with θ < 70° (Cu Kα). The A ring is found to be markedly displaced from the mean plane of the other three rings; hydrogen atoms are observed in difference electron density maps to be bonded to N21 and N23 of the nucleus. Details of the shape and dimensions of the nucleus are discussed.     

An oxo-centered carboxylate-bridged trinuclear complex: synthesis,crystal structure,and magnetic properties of [Cr3(μ3-O)(HL)2(H2O)3](ClO4)3

A new complex [Cr₃(μ₃-O)(HL)₂(H₂O)₃](ClO₄)₃, L = 1,4,7-triazacyclononane-N,N′,N′′-tripropionate(tacntp), has been synthesized and structurally characterized. The complex crystallizes in the orthorhombic, space group Pccn, with unit cell parameters a = 18.245(3) Å, b = 18.955(3) Å, c = 27.806(4) Å, α = 90°, β = 90°, γ = 90°. The complex has a trimetallic structure with three metal ions at the corners of a nearly equilateral triangle and the center occupied by a triply-bridging oxygen. Variable-temperature magnetic susceptibility indicates that the total spin value of the ground state is 3/2.     

CRYSTAL AND MOLECULAR STRUCTURE OF BIS(TRIPHENYLBENZYLPHOSPHONIUM) TETRABROMOCADMATE

Abstract

The molecular and crystal structure of bis(triphenylbenzylphosphonium)tetrabromocadmate has been determined by x-ray diffractometer data. Crystals are triclinic, space-group Pl with two formula units in a unit-cell of dimensions a = 12.506(6), b = 10.471(5), c = 18.396(13) Å, α = 93.07(4)°, β = 105.75(5)°, γ = 92.58(4)°. The structure was solved by direct and Fourier methods and refined by least-squares techniques to R = 0.061 for 3723 independent observed reflections. The structure consists of tetrabromocadmate (II) anions and triphenylbenzylphosphonium cations, both with a quasi-perfect tetrahedral symmetry around the cadmium and phosphorus atoms. The most significant average bond distances are: Cd-Br, 2.588(2) Å, P[sbnd]C (Phen), 1.794(5) Å and P[sbnd]CH₂, 1.806(6) Å. The P[sbnd]C (Phen) bonds are in slightly distorted staggered conformation (gauche-, gauche +, and trans) in respect of the C (Phen)-CH₂ bonds of the benzyl residues. The interatomic distances between the ions correspond to the usual Van der Waals distances.     

Semiconducting polymers based on charge-transfer complexes. II. Crystal structure of poly-N-4-[4-(methylthio)phenoxy]butyrylethylenimine

Of the two electron-donor-containing polymers whose synthesis was described in Part I of this series, one was crystalline. This polymer, which contains (methylthio)phenoxy electron-donating groups on the side chains of an N-acyl-substituted polyethylenimine, could be indexed in a triclinic unit cell of dimensions a = 4.35 Å, b = 24.0 Å, c = 12.7 Å, and α = β = γ = 90°. The polymer has the side chains alternating on each side of the polymer backbone. They extend to form at 24.0 Å repeat in that direction. The thickness of the ribbonlike molecule is 4.35 Å, while the repeat distance along the polymer backbone is 12.7 Å, which includes four monomer units.     

Ionic mobility and <Superscript>19</Superscript>F MAS NMR spectra of lithium octafluorozirconate Li<Subscript>4</Subscript>ZrF<Subscript>8</Subscript>

A new 1D cadmium coordination polymer [Cd(PhCOO)₂(bbbm)] _n (1) (bbbm = 1,1′-(1,4-butanediyl)bis-1H-benzimidazole ) is synthesized under hydrothermal conditions and characterized by elemental analysis, IR, TG, and X-ray single-crystal diffraction. Compound 1 crystallizes in the triclinic system, space group P-1 with a = 10.4289(17) Å, b = 12.5198(9) Å, c = 12.6130(9) Å, α = 118.4260(10)°, β = 95.1990(10)°, γ = 94.3820(10)°, V = 1428.8(3) ų, Z = 2. In the structure of 1, each cadmium center is six-coordinated in a strongly distorted octahedron by two N and four O atoms; an infinite one-dimensional linear chain was built by the flexible bbbm ligand that adopts a bis-monodentate bridging mode linking Cd^II atoms.     

Crystal structure of poly(m-phenylene isophthalamide)

The crystal structure of poly(m-phenyulene isophthalamide) was determined by x-ray analysis. The triclinic cell, with a = 5.27 Å, b = 5.25 Å, c (fiber axis) = 11.3 Å, α = 111.5°, β = 111.4° and γ = 88.0° and space group P1, contains one monomeric unit. The crystal density is 1.47 g/cc. The molecules in the crystal are contracted by 1 Å per monomeric unit from the fully extended conformation, and the planes of the benzene rings and adjacent amide groups make angles of about 30°. The crystal is composed of molecular chains connected by N? H···O hydrogen bonds along the a and b axes forming a “jungle gym” network structure. The low tensile modulus of this polymer as compared with that of poly(p-phenylene terephthalamide) is attributed to the contracted molecular conformation.     

THE CRYSTAL STRUCTURES OF AMMONIUM AND SODIUM 2-AMINO-3,5-DICHLOROBENZOATES

Abstract

The crystal structures of ammonium and sodium 2-amino-3,5-dichlorobenzoates were determined by the X-ray diffraction method. The ammonium salt crystallizes in the monoclinic system (space group P2₁/c) with a = 13.941(3), b = 9.128(3), c = 7.349(2) Å, β = 90.80(3)° and Z = 4. The structure consists of an ammonium cation hydrogen bonded to a carboxylate oxygen of the 2-amino-3,5-dichlorobenzoate anion. The sodium salt of 2-amino-3,5-dichlorobenzoic acid crystallizes in the triclinic system (space group P 1) with a = 8.033(2), 6 = 8.944(2), c = 17.350(3) Å, α = 76.72(3)°, β = 79.69(3)°, γ = 72.54(3)° and Z = 4. The compound is a polymer in which the sodium ions are coordinated by carboxylate oxygen atoms of the organic ligand and water molecules in an octahedral arrangement. IR spectra of the salts are discussed.     

Crystal Structure of a Cadmium Iodate Monohydrate: Cd(IO3)2·H2O

Single crystals of Cd(IO₃)₂·H₂O are obtained by slow evaporation of aqueous solutions of CdCl₂ and KIO₃. This compound crystallizes in the triclinic space group P1¯ [a = 7.119(2), b = 7.952(2), c = 6.646(2)Å, α = 102.17(2)°, β = 114.13(2)°, γ = 66.78(4)°]. The structure consists in Cd — (μ2‐O)₂ — Cd dimers with a metal — metal distance of 3.74Å. These dimers are connected through two iodate bridges resulting in layers parallel to the (010) plane. The 3D linkage is ensured by I1 — O1 long bonds (2.775Å).     

Spectroscopic studies and X-ray crystal structures of charge-transfer complexes of 1,4,7-trithiacyclononane with diiodine

1,4,7-Trithiacyclononane ([9]aneS₃) reacts with molecular diiodine in CH₂Cl₂ to form a 1:1 adduct. The formation constant and the thermodynamic parameters of this adduct have been determined by UV-visible spectra of several solutions at the temperatures of 15, 20, 25, 30, and 35°C. The ¹³C NMR spectra show that adducts with higher ligand/diiodine molar ratios are formed. Two neutral charge-transfer molecular compounds having formula 2[9]aneS₃ · 4I₂ ( I ) and [9]aneS₃ · 3I₂ · ( II ) have been obtained as crystals. The crystals of I are triclinic (a = 8.498(2) Å, b = 13.984(4) Å, c = 14.898(6) Å, α = 65.57(2)°, γ = 89.19(2)°, γ = 81.26(2)°, Z = 2, space group P1; R = 0.025) and contain units formed by two [9]aneS₃ molecules connected by a diiodine molecule; one [9]aneS₃ binds two other diiodine molecules, while the second binds only one other diiodine molecule. The crystals of II are monoclinic (a = 13.810(2) Å, b = 9.829(4) Å, c = 16.198(6) Å, β = 113.41(2)°, Z = 4, space group P2₁/c; R = 0.019) and contain molecules of [9]aneS₃ binding three diiodine molecules. FT-Raman spectra in the characteristic v(I–I) region, carried out on the solid adducts, are discussed in comparison with the structural parameters.     

Röntgenographische und spektroskopische Untersuchungen an Ba2Ni(N3)6· 3H2O

Preparation and X-Ray Examination of Ba₂Ni(N₃)₆ · 3 H₂O Ba₂Ni(N₃)₆ · 3 H₂O has been prepared by the reaction of an aqueous solution of Ba(N₃)₂ with basic nickel azide. The crystals are green, the lattice constants are: a = 7.09 Å, b = 7.09 Å, c = 16.30 Å, α = 74.58°, β = 105.42°, γ = 97.10°, N = 2. Optical spectra point to an octahedral microsymmetry of the azide ions around nickel.     

Quecksilberverbindungen mit Cyancarbanionen. I. Synthese und Kristallstruktur von Diquecksilber(I)-bis(tricyanmethanid)

Mercury Compounds with Cyancarbanions. I . Synthesis and Crystal Structure of Dimercury(I)-bis(tricyanmethanide ) With the triclinic unit cell, space group P1 , with the lattice constants a = 5.2794(1) Å, b = 9.9279(1) Å, c = 11.3376(2) Å, α = 71.004(4)°, β = 76.459(2)° and γ = 74.601(4)° are two formula units. The three-dimensional network, which characterizes the structure, results from dimercury(I) ions with sp³ hybridization, which form beside the homonuclear metal bonding three covalent bonds to cyanonitrogen atoms. The tricyanmethanide ion acts by losing symmetry as a tridentate ligand.     

Synthesis and structure of the p-hydroxybenzoic acid polymer

The synthesis and structure of the p-hydroxybenzoic acid polymer is described. The polymer was successfully prepared from either the phenyl ester of p-hydroxybenzoic acid or from p-acetoxybenzoic acid. With highly purified acetoxybenzoic acid, single crystals of the polymer could be prepared. The structure of the polymer was determined and shown to consist of a double helix where the two chains are in a reversed head-to-tail order. The unit cell dimensions are: a = 17.8 Å and c = 18.4 Å, where c corresponds to the chain length with a repeat distance of three units. The mechanism of polymerization and formation of the single crystal is discussed. The polymer displays a reversible high-temperature crystalline transition at 325–360°C (not a melting point). The transition was characterized by differential thermal analysis, differential calorimetry, thermal expansion coefficient measurements, high-temperature x-ray scans, and dielectric constant determinations. Orientation of the polymer chains during fabrication and changes in the mechanism of oxidative degradation above the crystal transition are described.     

Drei neue Selenoborato-closo-dodekaborate: Synthesen und Kristallstrukturen von Rb8[B12(BSe3)6], Rb4Hg2[B12(BSe3)6] und Cs4Hg2[B12(BSe3)6]

Three Novel Selenoborato- closo -dodecaborates: Syntheses and Crystal Structures of Rb₈[B₁₂(BSe₃)₆], Rb₄Hg₂[B₁₂(BSe₃)₆], and Cs₄Hg₂[B₁₂(BSe₃)₆] The three selenoborates Rb₈[B₁₂(BSe₃)₆] (P1, a = 10.512(5) Å, b = 10.450(3) Å, c = 10.946(4) Å, α = 104.53(3)°, β = 91.16(3)°, γ = 109.11(3)°, Z = 1), Cs₄Hg₂[B₁₂(BSe₃)₆] (P1, a = 9.860(2) Å, b = 10.740(2) Å, c = 11.078(2) Å, α = 99.94(3)°, β = 90.81(3)°, γ = 115.97(3)°, Z = 1), and Rb₄Hg₂[B₁₂(BSe₃)₆] (P1, a = 9.593(2) Å, b = 10.458(2) Å, c = 11.131(2) Å, α = 99.25(3)°, β = 91.16(3)°, γ = 116.30(3)°, Z = 1) were prepared from the metal selenides, amorphous boron and selenium by solid state reactions at 700 °C. These new chalcogenoborates contain B₁₂ icosahedra completely saturated with six trigonal-planar BSe₃ entities functioning as bidentate ligands to form a persubstituted closo-dodecaborate anion. The two isotypic compounds Rb₄Hg₂[B₁₂(BSe₃)₆] and Cs₄Hg₂[B₁₂(BSe₃)₆] are the first selenoborate structures containing a transition metal which are characterized by single crystal diffraction.     

A 2D Acentric Coordination Polymer, [Mn(HIDA)2(H2O)2], with a Strong Second‐Order Nonlinear Optical Effect

The crystal structure of [Mn(HIDA)₂(H₂O)₂] (Tetragonal, P4¯2₁c (no.114), a = b = 8.10(2)Å, c = 9.605(3)Å, α = β = γ = 90°, Z = 2, R = 0.051, wR² = 0.123 for 460 observed reflections) consists of infinite acentric 2D square grids with HIDA^— ions as bridging ligands. The 2D grids are interlocked(along the c axis) by hydrogen bonding. The Mn atoms are octahedrally coordinated by four O atoms of four HIDA^— ions (d(Mn—O)= 2.183(4)Å ) and two O atoms of two water molecules (d(Mn—OW) = 2.154(5)Å ). The results show that this acentric coordination polymer exhibits strong powder second harmonic generation (SHG) efficiency, ca. 1.9 times that of potassium dihydrogen phosphate, and remarkable thermal stability.     

Crystal Structure Determination of Thallium Carbodiimide,Tl2NCN

Orange‐red single crystals of thallium carbodiimide, Tl₂NCN, have been grown from an aqueous solution of cyanamide and thallium carbonate under strongly basic conditions. Tl₂NCN crystallizes in space group with a = 5.338(1), b = 6.626(2), c = 9.645(3) Å, α = 98.765(4)°, β = 98.685(4)°, γ = 113.178(4)°, and Z = 3; the structure can be considered a strongly distorted anti‐CdI₂ type. One finds two crystallographically different and irregular [NCN]Tl₆ octahedra in which the Tl–N distances of the three‐coordinate monovalent thallium ions lie between 2.52 and 2.72Å. The two symmetry‐inequivalent NCN^2? units adopt the carbodiimide shape, and the course of its molar volume as a function of the monovalent counter cation is analyzed.     

Crystal structure of (glycine) sodium nitrate Gly·NaNO3

The crystal structure of Gly·NaNO₃ was determined by single crystal diffraction methods (monoclinic crystal system, B11n, a = 14.339(3) Å, b = 9.136(3) Å, c = 5.263(3) Å, γ = 119.14(5)°). The structure is built from alternating layers of glycine organic molecules and inorganic layers consisting of Na⁺ ions and planar NO ₃ ^? ions stretching along the b axis. The surroundings of the Na atom include the oxygen atoms of the NO ₃ ^? groups and the oxygen atoms of glycine molecules. The structure has a system of hydrogen bonds.     

Polymorphic forms of nylon 3

The crystal structure of nylon 3 was studied, and four crystalline modifications were observed. Modification I, as determined from the x-ray diffraction pattern of drawn fibers, is similar to the α crystal structure of nylon 6. The unit cell is monoclinic; a = 9.33 Å, b = 4.78 Å, (fiber identity period), c = 8.73 Å, and β = 60°. The theoretical density for nylon 3 with four monomeric units in the unit cell is 1.39 g/cm³, and the observed density is 1.33 g/cm³. The space group is P2₁. The nylon 3 chains are in the extended planar zigzag conformation. Although other odd-numbered nylon form triclinic or pseudohexagonal crystals when oriented, drawn nylon 3 crystals are monoclinic. In addition to modification I, modifications II, III, and IV were studied. Lattice spacings of modifications II and III are equal to those of modification I. However x-ray diffraction intensities are different. Infrared spectra of those forms indicate an extended planar zigzag conformation of the chains. Modification IV is thought to correspond to the so-called smectic hexagonal form. No γ crystals were found, and it appears that polyamide chains with short sequences of methylene groups cannot form crystals of this type.     

The addition of carbonyl compounds to tetramesitylgermasilene and dimesitylgermylene

Hexamesitylsiladigermirane, 1 , has been photolyzed/thermolyzed in the presence of three representative carbonyl compounds: acetone, pivalaldehyde, and benzaldehyde. In each case, a [2 + 2] adduct between the carbonyl compound and Mes₂Ge = SiMes₂ was formed regioselectively to give a 2,3-silagermaoxetane. The 2,3-silagermaoxetanes have been fully characterized by IR and NMR (¹H, ¹³C, and ²⁹Si) spectroscopy and mass spectrometry. In two cases, the structures have been confirmed by X-ray crystallography: 4,4-dimethyl-2,2,3,3-tetramesityl-2,3-silagermaoxetane, 2a ; crystals are triclinic, space group P1 with Z = 2 in a unit cell of dimensions a = 12.318(3) Å, b = 12.436(2) Å, c = 11.884(2) Å, α = 100.13(1)°, β = 103.80(2)°, and γ = 89.97(2)°. The structure was solved by direct methods and refined by least squares on the basis of 2955 observed reflections to R₁ and wR₂ values of 0.0600 and 0.1363, respectively. The structure of 4-tert-butyl-2,2,3,3-tetramesityl-2,3-silagermaoxetane, 2b , was also determined; crystals are monoclinic, space group Cc with Z = 4 in a unit cell of dimensions a = 11.306(2) Å, b = 21.292(4) Å, c = 16.524(2) Å, and β = 106.83(1)°. The structure was determined by direct methods and refined by full-matrix least squares on the basis of 1817 observed reflections to R₁ and wR₂ values of 0.0621 and 0.1681, respectively. An adduct between dimesitylgermylene and the carbonyl compound was also isolated in each reaction. The structure of the adduct appears to depend upon the steric bulk of the group attached to the carbonyl carbon.