Absolute structure of (11E, 1S, 3S, 4R, 7S, 8R, 14S)-3,7-diiodo-4,8-epoxy-euniolide

3,7-Diiodo-4,8-epoxy-euniolide (2) was synthesized from euniolide (1) by the addition reaction of iodine in the presence of triphenylphosphine in CH₂Cl₂. The absolute structure of 2 was unambiguously determined by a combination of ¹H and ¹³C NMR, HREI mass spectroscopy, and x-ray single crystal analysis as (11E, 1S, 3S, 4R, 7S, 8R, 14S)-3,7-diiodo-4,8-epoxy-cembra-11,15-dien-16,14-olide. X-ray crystallographic data for 2: Orthorhombic P2₁2₁2₁ (#19), a = 10.9688(7), b = 11.3909(8), c = 16.885(1) Å, _calcd = 1.795 g cm^–3, and for Z = 4.     

Infrared spectra of glassy Se containing small amounts of S,Te, As,or Ge

The infrared transmission spectra of glassy Se containing 2.5 and 5.0 at % S, Te, As or Ge as well as pure Se were measured in the wavenumber region 400-60 cm^?1 at room temperature. Besides the absorption bands reported already for pure Se, well-defined bands were founds at 355 cm^?1 and 168 cm^?1 for the addition of S, and at 205 cm^?1 for Te. These new absorption bands attributed to Se₃S₅ and Se₅Te₃ mixed rings, respectively. For As, a strong absorption band appeared at 240 cm^?1. The band near 135 cm^?1 began to broaden and shift to lower frequency with As content. Two shoulder bands near 307 cm^?1 and 278 cm^?1 and a separated band at 195 cm^?1 were found for Ge. With increasing Ge concentration the band at 135 cm^?1 broadened and shifted to lower frequency. An interpretation for the new bands is presented on the basis of a molecular model.     

AgI, CdII, and HgII complexes with 2,5-bis(pyridyl)pyrazine ligands: syntheses, spectral analyses, single crystal, and powder X-ray analyses

2,5-Bis(4-pyridyl)pyrazine (4-bppz) and 2,5-bis(3-pyridyl)pyrazine (3-bppz) have been synthesized and characterized spectroscopically and crystallographically. 4-bppz [unit cell: a = 7.319(1), b = 5.746(1), c = 12.756(2) Å, = 93.16(1)° space group: P2₁/a] was characterized by X-ray single crystal diffraction methods while the structure of 3-bppz [unit cell: a = 10.9148(4), b = 4.5722(1), c = 11.4462(2) Å, = 109.571(2)° space group: P2₁/c] was determined from laboratory X-ray powder diffraction data. In these compounds, the pyrazine ring contains two symmetrically attached pyridine substituents with the nitrogen atom in the para positions for 4-bppz and in the meta positions for 3-bppz. Both compounds possess C_i symmetry with the pyridine rings twisted by 17.7° (4-bppz) and 2.6° (3-bppz) with respect to the pyrazine ring. 4-bppz was used in the formation of coordination compounds with silver(I) and cadmium(II). The silver(I) complex [Ag(OAc)(4-bppz)] _n (1) [unit cell: a = 8.472(1), b = 13.051(1), c = 19.063(2) Å, = 109.96(1)° space group: P2₁/c] is characterized by the formation of a perfectly linear chain containing the silver ions bridged by the ligand molecule, the latter using its pyridine nitrogen donor atoms for coordination. A pair of chains is interconnected by silver–silver interactions, the silver coordination sphere being completed by acetate anions. A similar one-dimensional coordination polymer, [Cd(OAc)₂(4-bppz)(MeOH)] _n (2) [unit cell: a = 8.680(1), b = 10.035(1), c = 13.445(1) Å, = 77.35(1), = 71.17(1), = 80.14(1)° space group: ], was obtained by the reaction of 4-bppz with Cd(OAc)₂. Ligand 3-bppz forms an analogous cadmium(II) complex, [Cd(OAc)₂(3-bppz)(MeOH)] _n (3) [unit cell: a = 9.306(1), b = 9.733(1), c = 11.550(1) Å, = 87.86(1), = 76.73(1), = 85.91(1)° space group: ], containing the molecules arranged in double zigzag chains. The reaction of 3-bppz with HgI₂ leads surprisingly to a binuclear complex, [Hg₂I₄(3-bppz)₂] (4) [unit cell: a = 17.555(1), b = 12.973(1), c = 16.195(1) Å, = 115.32(1)° space group: C2/c]. Two ligand molecules are bridged by two mercury(II) ions forming a cyclic structure, the tetrahedral coordination sphere of the metal being completed by iodide anions.     

Structural,morphological, ionic conductivity,and thermal properties of pectin-based polymer electrolytes

New polymer electrolytes (PEs), potentially interesting for solid-state electrochemical devices applications, were synthesized by a solvent casting method using pectin and ionic liquid (IL) N,N,N-trimethyl-N-(2-hydroxyethyl)ammonium bis(trifluoromethylsulfonyl)imide ([N_{1 1 1 2(OH)}] [NTf₂]. The resulting electrolytes besides being moderately homogenous and thermally stable below 155°C, they also exhibited good mechanical properties. The SPE membranes were analyzed by differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and complex impedance spectroscopy.     

D-β,β-dimethylcysteic acid,its preparation,structure, and spectroscopic properties

The X-ray crystal structure ofd-,-dimethylcysteic acid, C₅H₁₁NO₅S, has been determined. The compound is monoclinic, space groupP2₁₄ (No. 4), with cell dimensionsa=8.133(1),b=8.094(1),c=6.3138(7) Å,=96.36(1)° andZ=2. The structure was solved by Patterson and electron density difference methods and refined toR=0.025,R _w=0.022 for 1081 reflections. Bond lengths and angles do not differ from those in similar structures. The crystal is held together by intermolecular hydrogen bonds. The vibrational spectra have been recorded and assigned and the¹ H and¹³C NMR spectra were measured.     

Effect of Temperature,Time, Concentration,Annealing, and Substrates on ZnO Nanorod Arrays Growth by Hydrothermal Process on Hot Plate

Crystallography Reports - Well aligned 1D ZnO nanostructures are important for optoelectronic and nanoscale electronic devices. In this report, 1D ZnO nanorods were synthesized by very simple, low...     

Crystal and molecular structure of dihydro-8b,8c-diphenyl-1H,3H,4H,5H,7H,8H,-2,6-dioxa-3a,4a,7a,8a-tetraazacyclopenta[def]fluorene-4,8-dithione

The title compound C₂₀H₁₈N₄O₂S₂ crystallizes in the monoclinic space group P2₁/n witha=8.4930(1) Å,b=11.4880(1) Å,c=20.0709(2) Å, =94.933(1)°,V=1951.01(3) ų,Z=4. The crystal structure has been solved by vector search methods and refined by fullmatrix least-squares toR=0.04 for 2888 reflections and 116 restraints. The title compound has a suitable geometry for synthesizing receptor molecules with a cleft for selective complexation.     

Structures of anti,Z-4,4-dimethyl-3-thiosemicarbazide, syn,E,Z-2,4-dimethyl-3-thiosemicarbazide and syn,E-1-cyclopentano-3-thiosemicarbazone

The structures of three alkyl derivatives of thiosemicarbazide are described: anti,Z-4,4-dimethyl-3-thiosemicarbazide (1), syn,E,Z-2,4-dimethyl-3-thiosemicarbazide (2), and syn,E-1-cyclopentano-3-thiosemicarbazone (3). Crystal data: for 1: triclinic, P-1 (#2), a = 5.802(1)Å, b = 6.935(1)Å, c = 8.104(2)Å, = 78.35(1)°, = 82.13(1)°, = 70.71(1)°, and Z = 2; for 2: orthorhombic, Pbca (#61), a = 9.417(3)Å, b = 8.624(2)Å, c = 15.169(3)Å, and Z = 8; for 3: triclinic, P-1 (#2), a = 6.068(3)Å, b = 8.145(4)Å, c = 8.666(5)Å, = 83.75(4)°, = 86.16(5)°, = 74.07(4)°, and Z = 2. In general, molecules are linked by N–H···S hydrogen bonds with sulfurs accepting two or three hydrogen bonds. Structures 2 and 3, which adopt the syn conformation, form N–H···N intramolecular hydrogen bonds. The solid-state structures are consistent with their infrared and proton nuclear magnetic resonance spectra.     

Surface reconstruction phase diagrams for InAs, AlSb, and GaSb

We present experimental flux-temperature phase diagrams for surface reconstruction transitions on the 6.1 Å compound semiconductors. The phase transitions occur within or near typical substrate temperature ranges for growth of these materials by molecular beam epitaxy and therefore provide a convenient temperature standard for optimizing growth conditions. Phase boundaries for InAs (0 0 1) [(2×4)→(4×2)], AlSb (0 0 1) [c(4×4)→(1×3)], and GaSb (0 0 1) [(2×5)→(1×3)] are presented as a function of substrate temperature and Group V-limited growth rate (proportional to flux), for both cracked and uncracked Group V species. We discuss differences between materials in the slopes and offsets of the phase boundaries for both types of Group V species.     

Expression, purification, crystallization, and preliminary X-ray crystallographic analysis of OXA-17, an extended-spectrum β-lactamase conferring severe antibiotic resistance

OXA-17, an extended-spectrum β-lactamase (ESBL) conferring severe antibiotic resistance, hydrolytically inactivates β-lactam antibiotics, inducing a lack of eradication of pathogenic bacteria by oxyimino β-lactams and not helping hospital infection control. Thus, the enzyme is a potential target for developing antimicrobial agents against pathogens producing ESBLs. OXA-17 was purified and crystallized at 298 K. X-ray diffraction data from OXA-17 crystal have been collected to 1.85 Å resolution using synchrotron radiation. The crystal of OXA-17 belongs to space group P2₁2₁2₁, with unit-cell parameters a = 48.37, b = 101.12, and c = 126.07 Å. Analysis of the packing density shows that the asymmetric unit probably contains two molecules with a solvent content of 54.6%.     

Design, synthesis, and structure of novel cesium receptors

The podand, bis(2-methoxyphenoxy)m-xylene (1), was designed and synthesized as a potential host for the cesium ion. Its structure was determined by single crystal X-ray diffraction. It crystallizes in P2₁/c with cell dimensions: a = 8.5723(7) Å, b = 8.3931(14) Å, c = 25.2879(26) Å, = 96.224(9), and V = 1808.7(4) ų. A crown derivative, tribenzo-21-crown-6 (2), was also prepared and structurally characterized. It also crystallizes in P2₁/c with cell dimensions: a = 15.5825(13) Å, b = 15.8648(16) Å, c = 8.8266(7) Å, = 95.247(6), and V = 2172.9(3) ų. The structures exhibit hydrogen bonding, and are evaluated in terms of complementarity and preorganization for cesium binding.     

Synthesis,crystal growth,spectral, thermal and optical properties of acenaphthene picrate

The crystalline material of acenaphthene picrate (ACP) was synthesized and the single crystals of the title compound grown by slow evaporation solution growth technique. The solubility of the complex compound was estimated using different solvents as chloroform, ethanol, (1:1) chloroform ‐ acetone mixture. The material was characterized through elemental analysis; powder XRD, NMR and FTIR techniques. The various planes of reflection have been identified from the XRD powder pattern. The formation of the charge transfer complex was confirmed by UV‐VIS spectroscopy. The thermal stability of the crystals was studied using TG/DTA analyses techniques. The second harmonic generation (SHG) of the material was confirmed by using Nd: YAG laser. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Mn, Mg, and Zn ilmenite group titanates: A reconnaissance rietveld study

Ecandrewsite-geikielite (Zn_1/2Mg_1/2TiO₃), ecandrewsite-pyrophanite (Zn_1/2Mn_1/2TiO₃), pyrophanite-geikielite (Mg_1/2Mn_1/2TiO₃), and ecandrewsite-pyrophanite-geikielite (Zn_1/3Mn_1/3Mg_1/3TiO₃) titanates were synthesized at 900–1000°C at ambient pressure. All of the compounds adopt R— ilmenite-type structures. These structures were refined by the Rietveld method from X-ray powder diffraction data. Unit cell parameters and unit cell volumes decrease with decreasing average radii of the A ²⁺ cation. All structures consist of distorted AO ₆ and TiO₆ octahedra. In common with pyrophanite and ilmenite, the distortion of the AO ₆ octahedra is less than that of the TiO₆ octahedra. Data are given for the volumes and distortion indexes of all coordination polyhedra. Published in Russian in Kristallografiya, 2006, Vol. 51, No. 3, pp. 417–424. The text was submitted by the authors in English.     

Structure, thermal behavior, and IR investigation of a new organic sulfate

[1-(2-ammoniumethyl) piperazinium] sulfate denoted PIPS has a monoclinic unit cell. The parameters are: a = 6.6521(3), b = 7.8756(5), c = 19.197(1) Å, = 94.43(1)° and the space group is P2₁/n. The preparation, thermal analysis, and IR spectrometric investigation are described. The PIPS structure exhibits a complex three-dimensional network of H-bonds connecting all its components.     

1,2,3,4,5,6,7,8-Octahydroanthracene-9,10- dicarbonitrile at 172, 216, 256, and 297 K

Octahydroanthracenedicarbonitrile is monoclinic, space group P2₁/c, at 172 K, a = 4.723(7), b = 8.254(3), c = 16.190(7) Å, = 91.76(8)°, Z = 2, V = 630.8(12) ų. The molecule, located on a center of symmetry, is disordered between the two senses of puckering in the aliphatic ring. The structure was also determined at 216, 256, and 297 K. The disorder increases with increasing temperature and can be described by a van't Hoff relationship with H = 5.2(3) kJ mol^–1 and S = 13.8(12) J K^–1 mol^–1.     

Nanostructured crystals of fluorite phases Sr1 − x R x F2 + x (R are rare-earth elements) and their ordering. I. Crystal growth of Sr1 − x R x F2 + x (R = Y,La, Ce,Pr, Nd,Sm, Gd,Tb, Dy,Ho, Er,Tm, Yb,and Lu)

Crystallography Reports - Crystals of nonstoichiometric phases Sr1 − x R x F2 + x (R are 14 rare-earth elements) and the ordered phase Sr4Lu3F17 with a trigonally distorted fluorite lattice...     

Structures of 2-, 3-, and 4-methyl-9-oxothioxanthenes

The structures of 2-, 3-, and 4-methyl-9-oxothioxanthenes (2-, 3-, and 4-TX, respectively) were determined by single crystal x-ray methods. The molecules are folded by 2–3° about their SC=O lines. Bond distances and angles vary only slightly as a function of the methyl substitution position, and reveal no inherent structural reason for the long-range nmr couplings observed between the ring and methyl protons. The molecular packings exhibit interesting similarities as well as subtle differences that result from variation of the methyl position. Crystals of 2-TX are orthorhombic, space groupPn2₁ a,a=10.807(1),b=4.024(2),c=24.827(3) Å,Z=4,R=0.059 for 715 observed reflections. Crystals of 3-TX are orthorhombic, space groupPbc2₁,a=3.999(1),b=25.051(2),c=10.758(1)Å,Z=4,R=0.041 for 1382 observed reflections. Crystals of 4-TX are triclinic, space groupP¯1,a=7.118(1),b=7.907(2),c=10.415(2) Å,=77.74(1),=74.35(1), =73.96(1)°,Z=2,R=0.043 for 1542 observed reflections.Deceased.     

2-hydroxy-1-naphthaldehyde-derived Schiff bases: synthesis, characterization, and structure

Four Schiff base molecules were synthesized from the condensation of 2-hydroxy-1-naphthaldehyde with various amines having additional ligating centers, and the resulting products were characterized by analytical and spectral methods, and also by single crystal X-ray diffraction. 2-(-Naphthalideneamino)-2-methyl-1-propanol, 1, is orthorhombic, P2₁2₁2₁, a = 9.918(1), b = 12.629(1), c = 10.416(1) Å. 2-(-Naphthalideneamino)-2-hydroxymethyl-1-propanol, 2, is monoclinic, P2₁/c, a = 14.522(3), b = 9.723(2), c = 9.534(9) Å, = 107.75(4)°. 2-(-Naphthalideneamino)-2-hydroxymethyl-1,3-propanediol, 3, is monoclinic, P2₁/c, a = 20.981(9), b = 5.943(3), c = 10.549(5) Å, = 91.23(3)°. 2-(-Naphthalideneamino)-pyridine, 4, is monoclinic, P2₁/c, a = 5.804(4), b = 17.363(2), c = 24.032(11) Å, = 92.03(5)°. The molecular structures of these were found to be in extended conformation where the aromatic moiety is coplanar with that of the imine bond and the imine bond exhibited trans-geometry. The naphthyl moiety in each of these molecules is stabilized in quinoid form in the solid state. Interesting lattice structures were noticed owing to intermolecular interactions.     

Crystal Forms of the Antiepileptic Lamotrigine: Molecular Salts and Solvates with Fluorobenzoic Acid,Nicotinic Acid, 2-Thiobarbituric Acid, 3-Picoline and Butyl Alcohol

Abstract  

The crystal structures of three salts and two solvated multicomponent crystals of lamotrigine with 4-fluorobenzoic acid, nicotinic acid, 2-thiobarbituric acid, 3-picoline and butyl alcohol are reported. Compound 1a crystallizes in monoclinc system, space group P2₁ with a = 13.3860(5) ?, b = 8.3420(3) ?, c = 15.5200(6) ?, β = 93.524(1)°, V = 1729.78(11) ?³, and Z = 2. Compound 1b crystallizes in monoclinic system, space group P2₁/c with a = 10.6625(7) ?, b = 16.2575(11) ?, c = 13.6346(9) ?, β = 100.904(1)°, V = 2320.8(3) ?³, and Z = 4. Compound 1c crystallizes in triclinic system, space group P[`1] \overline{1} , with a = 10.1309(7) ?, b = 12.0260(8) ?, c = 14.0826(10) ?, α = 71.783(1)°, β = 86.451(1)°, γ = 80.902(1)°, V = 1609.10(19) ?<sup>3</sup>, and Z = 1. Compound 1d crystallizes in monoclinic system, space group P2<sub>1</sub>/c with a = 14.9570(10) ?, b = 8.0230(6) ?, c = 13.8162(10) ?, β = 102.884(1)°, V = 1616.2(2) ?<sup>3</sup>, and Z = 4. Compound 1e crystallizes in triclinic system, space group P[`1] \overline{1} , with a = 7.5710(6) ?, b = 8.5721(7) ?, c = 13.5532(11) ?, α = 85.364(1)°, β = 79.632(1) (1)°, γ = 86.188(1)°, V = 861.19(12) ?³, and Z = 2. Characteristic R₂²(8) dimer is observed in all five structures. A complete hydrogen bonded motif analysis is described. Lamotrigine-lamotrigine base pair is observed in all the structures, except in (1b). In (1c), the R₂²(7) dimer is noticed while, in all other structures R₂²(8) dimer exist between the lamotrigine-lamotrigine base pair. In all the six structures, chlorine atoms of the lamotrigine molecules are not involved in any interactions.     

Bulletin of the national committee of Russian crystallographers,No.1, July, 2011

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Bulletin of the national committee of Russian crystallographers, No.1, July, 2011