Structure determination of the silver carboxylate dimer [Ag(O2C20H39)]2, silver arachidate, using powder X-ray diffraction methods

2012 ◽  
Vol 27 (2) ◽  
pp. 99-103 ◽  
Author(s):  
Peter W. Stephens ◽  
James A. Kaduk ◽  
Thomas N. Blanton ◽  
David R. Whitcomb ◽  
Scott T. Misture ◽  
...  
Keyword(s):  
Density Functional ◽  
Structural Model ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
One Dimensional ◽  
X Ray ◽  
Cell Dimensions ◽  
Silver Carboxylate ◽  
Pseudo Potential

High-resolution powder X-ray diffraction and density functional plane wave pseudo-potential techniques have been used to obtain an optimized structural model of silver arachidate, [Ag(O2C(CH2)18CH3]2. The unit cell is triclinic, space group P-1 with cell dimensions of a = 4.1519(10) Å, b = 4.7055(10) Å, c = 53.555(4) Å, α = 89.473(15)°, β = 87.617(5)° and γ = 76.329(5)°. The structure is characterized by an 8-membered ring dimer of Ag atoms and carboxyl groups joined by four-member Ag–O rings with fully extended zigzag side chains, giving rise to one-dimensional chains along the b-axis.

Crystal structure determination of the silver carboxylate dimer [Ag(O2C22H43)]2, silver behenate, using powder X-ray diffraction methods

2011 ◽  
Vol 26 (4) ◽  
pp. 313-320 ◽  
Author(s):  
Thomas N. Blanton ◽  
Manju Rajeswaran ◽  
Peter W. Stephens ◽  
David R. Whitcomb ◽  
Scott T. Misture ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Density Functional ◽  
Structural Model ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
X Ray ◽  
Cell Dimensions ◽  
Alkyl Side Chains ◽  
Silver Carboxylate

High-resolution powder X-ray diffraction has been used to determine the crystal structure of silver behenate, [Ag(O2C(CH2)20CH3]2. Using CASTEP density functional plane wave pseudopotential techniques to obtain an optimized structural model, Rietveld refinement of the structure gives Rwp = 8.66%. The unit cell is triclinic, space group P1, with cell dimensions of a = 4.1769(2) Å, b = 4.7218(2) Å, c = 58.3385(1) Å, α = 89.440(3)°, β = 89.634(3)°, γ = 75.854(1)°. The structure is characterized by an 8-membered ring dimer of Ag atoms and carboxyl groups with a fully extended all-trans configuration of the alkyl side chains. The dimers are joined by four-membered Ag-O rings creating a polymeric network, giving rise to one-dimensional chains along the b-axis. This structure is supported by EXAFS measurements of the local structure around the silver atoms and IR measurements.

X-Ray-Diffraction Study and Determination of Absolute Configuration of the Anticancer Drug S(–) Cyclophosphamide (Endoxan, Cytoxan, NSC-26271)

1977 ◽  
Vol 32 (9-10) ◽  
pp. 672-677 ◽  
Author(s):  
D. A. Adamiak ◽  
W. Saenger ◽  
R. Kinas ◽  
W. J. Stec
Keyword(s):  
Absolute Configuration ◽  
Direct Methods ◽  
Ratio Test ◽  
Equatorial Position ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
X Ray ◽  
Cell Dimensions ◽  
Determination Of Absolute Configuration

Abstract (-) Cyclophosphamide (1) crystallized from tetrachlorom ethane in the triclinic space group P1 with cell dimensions a = 10.500 (4) Å, b = 10.490 (4) Å, c = 10.761 (4) A, α = 110.0 (2) ° , β = 11 0.0(2)°, γ = 1 0 8.9(2)°. Three molecules are contained in the unit cell. The X-ray analysis was based on diffractometer measurement of 2635 independent reflections and the structure was solved by Patterson and direct methods. The final R and R w factors after full-matrix least-squares refinement are 0.0717 and 0.0677, respectively. The absolute configuration is S based on Hamilton’s R-factor ratio test. The oxazaphosphorinane ring exists in a chair form with the bis-β-chloroethyl-amino group in equatorial position and about perpendicular to and bisecting .The structure is similar to that found in racemic 1 except a different conformation about one ethyl-amino N-C bond.

Formalism for the determination of intermediate stress gradients using X-ray diffraction

2009 ◽  
Vol 42 (2) ◽  
pp. 192-197 ◽  
Author(s):  
Thomas Gnäupel-Herold
Keyword(s):  
Lattice Strain ◽  
Narrow Line ◽  
X Ray Diffraction ◽  
Beam Spot ◽  
Strain Measurements ◽  
One Dimensional ◽  
X Ray ◽  
Stress Gradients ◽  
Shaped Beam

A method is outlined that allows the determination of one-dimensional stress gradients at length scales greater than 0.2 mm. By using standard four-circle X-ray diffractometer equipment and simple aperture components, length resolutions down to 0.05 mm in one direction can be achieved through constant orientation of a narrow, line-shaped beam spot. Angle calculations are given for the adjustment of goniometer angles, and for the effective azimuth and tilt of the scattering vector for general angle settings in a four-circle goniometer. The latter is necessary for the computation of stresses from lattice strain measurements.

Polysulfonylamine, CXXV [1]. Neue Komplexe von Disulfonylaminen mit Kronenethern - im voraus entworfen oder zufällig entdeckt / Polysulfonylamines, CXXV [1]. New Complexes of Disulfonylam ines with Crown Ethers - Preconceived or Discovered by Serendipity

2000 ◽  
Vol 55 (3-4) ◽  
pp. 299-316 ◽  
Author(s):  
Dagmar Henschel ◽  
Karna Wijaya ◽  
Oliver Moers ◽  
Armand Blaschette ◽  
Peter G. Jones
Keyword(s):  
Hydrogen Bonds ◽  
X Ray Diffraction ◽  
Ladder Structure ◽  
Triclinic Space Group ◽  
One Dimensional ◽  
X Ray ◽  
Bonding System ◽  
Supramolecular Aggregate ◽  
Guest Species ◽  
The One

Abstract In a study aim ed at the „deconstruction“ of the supramolecular aggregate 3(18C6) · 2HN( SO2Me)2 (1,18C6 = 18-crown-6), which is known to display a ladder structure with two isotactic [18C6 - Me SO2N(H)SO2Me···)∞ polymers forming the uprights and symmetrically N - H···O bonded 18C6 rings providing the rungs, the following crystalline complexes were isolated and (except for 2b) characterized by low-temperature X-ray diffraction: 18C6-ClN (SO2Me)2 (2a, triclinic, space group P1̅, Z = 2), 18C6-PhN (SO2Me)2 (2b), 18C6 -MeN(SO2Me)2 (3, monoclinic, P21/c, Z = 8), Bz18C6-HN(SO2Me)2 (4, Bz18C6 = benzo-18-crown-6, monoclinic, P21/n, Z = 4), 18C6-2 MeN (SO2Me)2 (5, triclinic, P1̅, Z = 1), 18C6-Me2SO- HN( SO2Me) (SO2Ph) (13, triclinic, P1̅, Z = 2), and 18C6-H2OMe2SO·2HN(SO2Me)2 (14, triclinic, P1̅, Z = 2). Each of the one-dimensional polymers 2a (syndiotactic), 3 (disyndiotactic) and 4 (isotactic) mimics a single upright of 1; in contrast to 1 and 2a, where the intra-catemer connectivity solely relies on S - Me ··· crow n and crown ··· O = S hydrogen bonds, this bonding system is reinforced in 3 by N -Me ··· crown and in 4 by N - H ··· crown hydrogen bonds. Complex 5 is monomeric and matches a fragment formally extruded from the catemer 3; moreover, 3 and 5 represent a rare case of two structurally characterized 18C6 complexes containing the same uncharged guest species in distinct molecular ratios. The surprising structure of the quaternary adduct 14 exhibits an [18C6 ··· MeSO2N(H)SO2Me ··· ]∞ chain, which can be regarded both as an isolated, though unmodified upright from the ladder 1 and, being syndiotactic, as a stereochemical analogue of 2a; the potentially rung-forming *NH functions in the chain are blocked by hydrogenbonded side chains of the type * N - H ··· water ··· sulfoxide ··· H - N (SO2Me)2. The ternary complex 13 consists of chains [18C6 ··· Me2SO ··· H - N (SO2Ph)SO2Me···]∞ and is not closely related to the other structures

scholarly journals Structural Refinement and Density Functional Theory Study of Synthetic Ge-Akaganéite (β-FeOOH)

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 239
Author(s):  
Donghoon Chung ◽  
Changyun Park ◽  
Woohyun Choi ◽  
Yungoo Song
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Structural Model ◽  
Dispersion Correction ◽  
Chemical Formula ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Twisted Cube

In this study, we propose a revised structural model for highly ordered synthetic Ge-akaganéite, a stable analogue of tunnel-type Fe-oxyhydroxide, based on the Rietveld refinement of synchrotron X-ray diffraction data and density functional theory with dispersion correction (DFT-D) calculations. In the proposed crystal structure of Ge-akaganéite, Ge is found not only in the tunnel sites as GeO(OH)3− tetrahedra, but also 4/5 of total Ge atoms are in the octahedral sites substituting 1/10 of Fe. In addition, the tunnel structures are stabilized by the presence of hydrogen bonds between the framework OH and Cl− species, forming a twisted cube structure and the GeO(OH)3− tetrahedra corner oxygen, forming a conjugation bond. The chemical formula of the synthetic Ge-akaganéite was determined to be (Fe7.2Ge0.8)O8.8(OH)7.2Cl0.8(Ge(OH)4)0.2.

Synthesis, Crystal Structure and Magnetic Properties of a Copper(II) p-Formylbenzoate Complex

2012 ◽  
Vol 67 (11) ◽  
pp. 1185-1190 ◽  
Author(s):  
Jin-Li Qi ◽  
Wei Xu ◽  
Yue-Qing Zheng
Keyword(s):  
Room Temperature ◽  
Magnetic Measurements ◽  
X Ray Diffraction ◽  
Complex Molecules ◽  
Triclinic Space Group ◽  
X Ray ◽  
Cell Dimensions ◽  
Ferromagnetic Interactions ◽  
Aqueous Conditions ◽  
Discrete Complex

A new Cu(II) complex was prepared at room temperature from the reaction of p-formylbenzoic acid, phenanthroline, CuCl2⋅2H2O, and NaOH under ethanolic aqueous conditions. The complex has been characterized by X-ray diffraction, IR spectroscopy, TG-DTA analyses, and magnetic measurements. Single-crystal X-ray diffraction analysis indicated that the complex crystallizes in the triclinic space group P1̄ with the cell dimensions a=7.875(2), b=10.724(2), c=15.317(3) Å , α =102.65(3), β =93.71(3), γ =107:64(3)°. The Cu atoms are in the environment of distorted CuN2O3 tetragonal pyramids. These discrete complex molecules are packed through intermolecular π...π-stacking interactions and C-H...O hydrogen bonds forming a supramolecular structure. The title complex obeys the Curie-Weiss law with a Curie constant C=0:53 cm3 K mol-1 and a Weiss constant θ = -0:27 K. The shape of the xmT curve is characteristic of weak ferromagnetic interactions between the Cu(II) centers from 300 to 7 K, while there are weak antiferromagnetic interactions below 7 K.

A cyanide-bridged FeIII–MnII heterobimetallic one-dimensional coordination polymer: synthesis, crystal structure, experimental and theoretical magnetism investigation

2019 ◽  
Vol 75 (11) ◽  
pp. 1475-1481 ◽  
Author(s):  
Wenlong Lan ◽  
Zhen Zhou ◽  
Jie Li ◽  
Yong Dou ◽  
Xiaoyun Hao ◽  
...  
Keyword(s):  
Coordination Polymer ◽  
Single Crystal ◽  
Density Functional ◽  
Linear Chain ◽  
Coupling Constants ◽  
Antiferromagnetic Coupling ◽  
Chain Model ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
X Ray

A new cyanide-bridged FeIII–MnII heterobimetallic coordination polymer (CP), namely catena-poly[[[N,N′-(1,2-phenylene)bis(pyridine-2-carboxamidato)-κ4 N,N′,N′′,N′′′]iron(III)]-μ-cyanido-κ2 C:N-[bis(4,4′-bipyridine-κN)bis(methanol-κO)manganese(II)]-μ-cyanido-κ2 N:C], {[FeMn(C18H12N4O2)(CN)2(C10H8N2)2(CH3OH)2]ClO4} n , (1), was prepared by the self-assembly of the trans-dicyanidoiron(III)-containing building block [Fe(bpb)(CN)2]− [bpb2− = N,N′-(1,2-phenylene)bis(pyridine-2-carboxamidate)], [Mn(ClO4)2]·6H2O and 4,4′-bipyridine, and was structurally characterized by elemental analysis, IR spectroscopy, single-crystal X-ray crystallography and powder X-ray diffraction (PXRD). Single-crystal X-ray diffraction analysis shows that CP 1 possesses a cationic linear chain structure consisting of alternating cyanide-bridged Fe–Mn units, with free perchlorate as the charge-balancing anion, which can be further extended into a two-dimensional supramolecular sheet structure via inter-chain π–π interactions between the 4,4′-bipyridine ligands. Within the chain, each MnII ion is six-coordinated by an N6 unit and is involved in a slightly distorted octahedral coordination geometry. Investigation of the magnetic properties of 1 reveals an antiferromagnetic coupling between the cyanide-bridged FeIII and MnII ions. A best fit of the magnetic susceptibility based on the one-dimensional alternating chain model leads to the magnetic coupling constants J 1 = −1.35 and J 2 = −1.05 cm−1, and the antiferromagnetic coupling was further confirmed by spin Hamiltonian-based density functional theoretical (DFT) calculations.

A New Type of Coordination Polymer: Hydrothermal Synthesis, Crystal Structure, and Magnetic Properties of [(C10H8N2)2CuBr]Cu3Br4

1998 ◽  
Vol 547 ◽  
Author(s):  
Brenda R. Cabrera ◽  
Ru-Ji Wang ◽  
Jing Li ◽  
Tan Yuen
Keyword(s):  
Hydrothermal Synthesis ◽  
Structure Type ◽  
X Ray Diffraction ◽  
Monoclinic System ◽  
One Dimensional ◽  
X Ray ◽  
Paramagnetic Behavior ◽  
Cell Dimensions ◽  
Susceptibility Study ◽  
New Type

AbstractGrowth of [(C10H8N2)2CuBr]Cu3Br4(I) crystals was achieved using the hydrothermal synthesis. Single crystal X-ray diffraction analysis shows that this compound crystallizes in monoclinic system, space group P21/c (no. 14) with four formula units in the unit cell. The cell dimensions are the following: a = 16.769(2) Å, b = 23.873(6) Å, c = 6.523(2) Å, β = 98.37(3)°, V = 2584(1) Å3. The title compound represents a new structure type. It consists of one-dimensional ribbons of 1[(Cu3Br4)] extending along the c-axis and discrete [(C10H8N2)2CuBr]+ complexes. The magnetic susceptibility study indicates a paramagnetic behavior due to the Cu(II) in the complex cations. The effective paramagnetic moment was calculated to be 2.20 μB from fitting the χ(T) data.

Metal-selenolate chemistry: stereochemistry of adamantane-type clusters of formula [(μ-SePh)6(MSePh)4]2− (M = Zn and Cd)

1992 ◽  
Vol 70 (3) ◽  
pp. 792-801 ◽  
Author(s):  
Jagadese J. Vittal ◽  
Philip A. W. Dean ◽  
Nicholas C. Payne
Keyword(s):  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Bridging Ligands ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Space Groups ◽  
X Ray Crystallography ◽  
Cell Dimensions ◽  
Minimum Number

The structures of three tetramethylammonium salts containing anions of formula [(μ-SePh)6(MSePh)4]2− (M = Zn and Cd) were determined by single crystal X-ray diffraction techniques. The Zn salt crystallizes in different space groups depending upon the solvent combination used in the synthesis. Thus crystals of (Me4N)2[Zn4(SePh)10], 1, grown from a mixture of methanol, acetonitrile, and acetone are triclinic, space group [Formula: see text] with cell dimensions a = 13.214(2), b = 23.859(2), c = 13.072(1) Å, α = 91.134(8), β = 113.350(8), γ = 79.865(9)°, and Z = 2. In the absence of acetone, a solvated crystal (Me4N)2[Zn4(SePh)10]•CH3CN, 2, is formed, which belongs to the monoclinic space group P21/n with a = 14.248(1), b = 39.722(2), c = 13.408(1) Å, β = 97.132(5)°, and Z = 4. The Cd salt (Me4N)2[Cd4(SePh)10], 3, crystallizes in the monoclinic space group P21/c, with a = 20.830(2), b = 14.282(1), c = 25.872(1) Å, β = 99.626(6)°, and Z = 4. These three salts are the first examples of homoleptic, tetranuclear selenolatometal(II) anions with (μ-Se)6M4 cages of adamantane-type stereochemistry. In each case the phenyl substituents of the bridging ligands adopt the configuration [aae, aae, aee, aee], which has the minimum number of two 1,3-axial–axial non-bonding substituent interactions. Keywords: selenolate complexes, synthesis, X-ray crystallography, isomerism, adamantane stereochemistry.

Synthesis, Structure and Characterization of a Novel 3D Zinc Organophosphonate

2014 ◽  
Vol 936 ◽  
pp. 915-918
Author(s):  
Hui Duan Li
Keyword(s):  
Powder Diffraction ◽  
Organic Ligand ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
One Dimensional ◽  
X Ray ◽  
Open Framework ◽  
Solvothermal Conditions

A novel zinc organophosphonate was synthesized under solvothermal conditions by using [piperazine-1,4-diyldi (methylene)] bis (phosphonic acid) as a organic ligand. Single-crystal X-ray diffraction analysis reveals that compound 1 crystallized in the triclinic space group P-1 (No. 2). Compound 1 formulated as Zn (O3PCH2NHC4H8NHCH2PO3)·H2O. Compound 1 featured a 3D open-framework. Notably, the structure of compound 1 featured one-dimensional channel in the [00 direction. Water molecules were located in these channels. Further characterizations of compound 1 have been performed, including X-ray powder diffraction, IR, ICP and CHN analyses.

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