Die Kristall- und Molekülstruktur des Tris(ethylendiamin)cadmium(II)-dibenzohydroxamathydrates, CdC20H38O5N8

1984 ◽  
Vol 166 (3-4) ◽  
Author(s):  
Mariot Breitwieser ◽  
Siegfried Göttlicher ◽  
Helmut Paulus
Keyword(s):  
Space Group ◽  
Orthorhombic Crystals

AbstractOrthorhombic crystals of nearly 1 cm lengths have been obtained from a solution of cadmiumbenzohydroxamate in ethylenediamine. The space group is

The crystal structure of myoglobin III. Sperm-whale myoglobin

1957 ◽  
Vol 238 (1214) ◽  
pp. 305-324 ◽  
Keyword(s):  
Sperm Whale ◽  
Two Dimensional ◽  
Crystal Forms ◽  
Space Group ◽  
Spin Resonance ◽  
Orthorhombic Crystals ◽  
Optical Dichroism ◽  
Sperm Whale Myoglobin ◽  
Identical Crystal ◽  
Good Agreement

Myoglobin of Physeter catodon (sperm whale) forms monoclinic crystals with space group P 2 1 (type A ) in ammonium sulphate, and orthorhombic crystals with space group P 2 1 2 1 2 1 (type B ) in phosphate. Almost identical crystal forms are obtained from related species of whale. Two-dimensional Patterson projections have been computed from some principal zones of reflexions in each type of crystal. They are used to derive the chain directions of the poly­peptide chains in the molecules relative to the crystal axes, and to suggest plausible methods of packing in the two forms. The data are best fitted by a molecule having dimensions about 25 x 34 x 42 Å, the latter dimension being parallel to the chain direction. Measurements of electron-spin resonance (Bennett & Ingram 1956) and of optical dichroism have been used to determine the orientation of the planes of the haem group and the angle between them and the chains. It is concluded that the angle is 40 to 50° in the two forms, in good agreement with the value found for type F crystals in an earlier paper, namely, 41°. Thus in all three crystal types A , B and F the data are consistent with the molecule having the same set of dimensions, associated with a common chain direction and a common relation between chain direction and haem group.

scholarly journals Crystallization and diffraction of an Isl1–Ldb1 complex

2012 ◽  
Vol 68 (11) ◽  
pp. 1398-1401 ◽  
Author(s):  
Morgan S. Gadd ◽  
David A. Jacques ◽  
J. Mitchell Guss ◽  
Jacqueline M. Matthews
Keyword(s):  
Unit Cell ◽  
Homeodomain Protein ◽  
Unit Cell Parameters ◽  
Space Group ◽  
Cell Parameters ◽  
Lim Domains ◽  
Intramolecular Complex ◽  
Orthorhombic Crystals ◽  
Peptide Region ◽  
Lim Homeodomain

A stable intramolecular complex comprising the LIM domains of the LIM-homeodomain protein Isl1 tethered to a peptide region of Ldb1 has been engineered, purified and crystallized. The orthorhombic crystals belonged to space groupP2221, with unit-cell parametersa= 57.2,b= 56.7,c= 179.8 Å, and diffracted to 3.10 Å resolution.

Effect of Coordination on the Structure of Tris(N,N-Dimethylaminomethyl)phosphine Oxide

1993 ◽  
Vol 58 (6) ◽  
pp. 1354-1362 ◽  
Author(s):  
Pavel Vojtíšek ◽  
Jana Podlahová ◽  
Karel Malý ◽  
Jindřich Hašek
Keyword(s):  
Oxygen Atom ◽  
Phosphine Oxide ◽  
Major Part ◽  
Water Molecules ◽  
Space Group ◽  
Bond Lengths ◽  
Orthorhombic Crystals ◽  
Coordinated Water

Crystals of tris(N,N-dimethylaminomethyl)phosphine oxide (tmpo) are hexagonal, space group P63; a = 8.723(5), c = 10.636(5) Å, Z = 2, R = 0.039 for 384 observed reflections. The complex [Co(tmpo)2(H2O)2](ClO4)2, forms orthorhombic crystals, space group Pbca, a = 19.16(1), b = 10.576(2), c = 117.043(4) Å, Z = 4, R = 0.069 for 1 409 observed reflections. The molecule is centrosymmetric, with the Co atom lying in the center. The tmpo is coordinated through the oxygen atom and one of the nitrogen atoms. The coordination of the ligand brings about very small changes in the bond lengths and angles except for the P=O bond. The coordinated water molecules play a major part in the structure of [Co(tmpo)2(H2O)2](ClO4)2.

Optically Active Cyclopentadienyl Ligands from the Chiral Pool, Part 1. The Synthetic Utility of a Camphor-Derived Pentafulvene

2002 ◽  
Vol 57 (3) ◽  
pp. 338-342 ◽  
Author(s):  
Valeri Quindt ◽  
Mark Wallasch ◽  
Gotthelf Wolmershäuser ◽  
Helmut Sitzmann
Keyword(s):  
Optically Active ◽  
Tertiary Alcohol ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Cyclopentadienyl Ligands ◽  
Water Elimination ◽  
Synthetic Utility ◽  
Orthorhombic Crystals

AbstractStarting from (1R)-(+)-camphor, the reaction with cyclopentadienylmagnesium chloride gave the corresponding tertiary alcohol 1, which was transformed into the optically active pentafulvene 5-(1,7,7-trimethylbicyclo[2.2.1]heptan-2-ylidene)cyclopentadiene (2) by acidcatalyzed water elimination. Deprotonation with tert-butyllithium yielded the corresponding lithium 5-{(1R)-1,7,7-trimethylbicyclo[2.2.1]hept-2-en-2-yl}cyclopentadienide (3), which was converted into the non-racemic 1,1β-bis{(1R)-1,7,7-trimethylbicyclo[2.2.1]hept-2-en-2- yl}ferrocene (4). 4 forms orthorhombic crystals of the space group P212121 with a = 7.7163(4), b = 10.7381(6), and c = 28.804(2) A˚ , which have been subjected to X-ray diffraction.

Kubanartige Molybdän-Halogen-Schwefel-Clusterdithiophosphinate / Cubane Type Molybdenum-Halogen-Sulfur Clusterdithiophosphinates

1991 ◽  
Vol 46 (11) ◽  
pp. 1525-1531 ◽  
Author(s):  
Georg Borgs ◽  
Helmut Keck ◽  
Wilhelm Kuchen ◽  
Dietrich Mootz ◽  
René Wiskemann ◽  
...  
Keyword(s):  
Van Der Waals ◽  
Alkyl Halides ◽  
Type Structure ◽  
Cluster Core ◽  
Covalent Character ◽  
Space Group ◽  
Spectroscopic Investigations ◽  
Orthorhombic Crystals ◽  
Van Der Waals Radii ◽  
Tetraalkylammonium Halides

Diamagnetic clusters [Mo3X-μ-(S2)3-μ3(S)(R2PS2)3] 2-4 (2: X = Cl; 3: X = Br; 4: X = I; 2-4: a: R = Et; b: R = Pr; c: R = Bu) are conveniently obtained by reaction of [Mo3S7(R2PS2)3]+(R2PS2)- 1 either with alkyl halides RX or with tetraalkylammonium halides R4NX. Between halogen X and one of the S atoms of each disulfido bridge there exist bonds which seem to be mainly of covalent character. Thus X is incorporated into the cluster core leading to a cubane type structure. [Mo3ClS7(Et2PS2)3] forms orthorhombic crystals with space group Pnma, Z = 4, a = 1931.9(7), b = 1551.2(6), c = 1286.5(4) pm. Isostructural substructures of 3b, 4a and 4b (space group P21) were also studied. All these cluster molecules reveal similar core geometries with distances S—Cl 239.4(4), S—Br 305(1) and S—I 322.5(3) pm much less than the sum of the van der Waals radii. The results of structural and spectroscopic investigations are discussed.

Bisphenol Flukicides. V. The Crystal and Molecular Structures of 2,2'-(2,2-Dichlorovinylidene)bis(4-chloro-6-nitrophenol) and 4,4'-(2,2-Dichlorovinylidene)bis(2-chloro-6-nitrophenol)

1981 ◽  
Vol 34 (3) ◽  
pp. 559 ◽  
Author(s):  
D Hay ◽  
P Demunk ◽  
M Mackay
Keyword(s):  
Dihedral Angle ◽  
Molecular Structures ◽  
Dihedral Angles ◽  
Space Group ◽  
Crystal And Molecular Structures ◽  
Isomeric Compound ◽  
Phenyl Rings ◽  
Orthorhombic Crystals

Crystals of 2,2'-(2,2-dichlorovinylidene)bis(4-chloro-6-nitrophenol) (1), C14H6C14N206, are monoclinic and belong to the space group C2/c with a 17.135(5), b 7.201(2), c 15.406(5) �, β 118.40(2)�, Z 4. Orthorhombic crystals of the isomeric compound, 4,4'-(2,2-dichlorovinylidene)bis(2-chloro-6-nitrophenol) (2), belong to the space group P bcn with a 20.410(3), b 8.682(2), c 18.716(3) �, Z 8. The structures were deduced from diffractometer data. For (1), refinement with 956 terms measured with Mo Kα radiation converged at R 0.055; structure (2) was refined with 1475 terms measured with Cu Kα radiation to R 0.079. Molecule (1) has exact C2 symmetry, and the dihedral angle between the perpendiculars to the plane of the C-C-C bridge and the phenyl rings of 84.2(4)� defines a butterfly conformation. The conformation of (2) is twist with dihedral angles between the perpendiculars to the C-C-C bridge and phenyl rings of 61 .9(7) and 33.0(7)�.

The Absolute Structure of Latifoline

1992 ◽  
Vol 45 (2) ◽  
pp. 451 ◽  
Author(s):  
CCJ Culvenor ◽  
MF Mackay
Keyword(s):  
Single Crystal ◽  
Absolute Configuration ◽  
Crystallographic Analysis ◽  
Salt Hydrate ◽  
Space Group ◽  
X Ray ◽  
Orthorhombic Crystals ◽  
The Absolute ◽  
Absolute Structure

The absolute structure of latifoline, a pyrrolizidine diester alkaloid of retronecine and latifolic and angelic acids, has been defined by single-crystal X-ray crystallographic analysis of the hydrobromide salt hydrate. Orthorhombic crystals of C20H27NO7.HBr.H2O belong to the space group P 2′2′2′ with a 7.279(1), b 17.898(3), c 17.922(2) � and V 2334-9(8) � 3 . The structure has been refined to an R index of 0.054 for 1725 observed terms. The absolute configuration has been assigned by comparison with that of retronecine and also determined independently by X-ray examination of selected Bijvoet pairs. Our results have shown that the absolute structure of latifolic acid is 13S,14R,19S (2R,3S,4S in latifolic acid numbering), and not the stereoisomer reported recently by Roitman and Wong.

Multislice calculations for quasi-periodic and non-periodic objects

1990 ◽  
Vol 48 (4) ◽  
pp. 138-139
Author(s):  
R. Herrera ◽  
A. Gómez
Keyword(s):  
Electron Diffraction ◽  
Computer Simulations ◽  
Periodic Table ◽  
Amorphous Materials ◽  
Space Group ◽  
Essential Step ◽  
Shape Effects ◽  
Atomic Scattering ◽  
Diffraction Patterns ◽  
Periodic Continuation

Computer simulations of electron diffraction patterns and images are an essential step in the process of structure and/or defect elucidation. So far most programs are designed to deal specifically with crystals, requiring frequently the space group as imput parameter. In such programs the deviations from perfect periodicity are dealt with by means of “periodic continuation”.However, for many applications involving amorphous materials, quasiperiodic materials or simply crystals with defects (including finite shape effects) it is convenient to have an algorithm capable of handling non-periodicity. Our program “HeGo” is an implementation of the well known multislice equations in which no periodicity assumption is made whatsoever. The salient features of our implementation are: 1) We made Gaussian fits to the atomic scattering factors for electrons covering the whole periodic table and the ranges [0-2]Å−1 and [2-6]Å−1.

An HREM study of superstructures in Ca4Al6SO16

1990 ◽  
Vol 48 (4) ◽  
pp. 1066-1067
Author(s):  
Y.G. Wang ◽  
H.Q. Ye ◽  
K.H. Kuo
Keyword(s):  
Calcium Aluminate ◽  
Structural Model ◽  
Bright Spot ◽  
Sulphur Atom ◽  
Synthetic Compound ◽  
Space Group ◽  
Lattice Images ◽  
Cubic Structure ◽  
Good Agreement

A synthetic compound Ca4Al6SO16 (usually abbreviated as C4A3S) obtained by mixing CaO, A12O3 and CaSO4 powders and finally sintered at 1380°C is a cement with excellent hydraulicity and greatly expanding in application. It is hydralysed rapidly by water to form predominatly calcium aluminate hydrates and therefore unlikly to occur naturally, although structurally it may be regarded as an end member of the sodalite-hauynite series of naturally occuring minerals. C4A3S has a cubic structure with ao=9.19Å and space group . Fig.1 is the projection viewed down axis, in which there are two sets of 8C position in , namely CaI and CaII, occupied by the calcium atoms, respectively, and the ratio of occupations in these two sets of positions is about 3:1. This suggests that the calcium atoms can freely occupy these sites in various degrees and usually they almost locates on the CaI positions. A through-focus series of the lattice images were found in good agreement with the simulated ones. Each bright spot in the image taken at Scherzer defocus correspounds to a colunm of sulphur atom in the structural model (Fig.1).

Misfit Dislocations in the Ilmenite (FeTiO3)-Hematite (Fe2O3) System

1980 ◽  
Vol 38 ◽  
pp. 212-213 ◽  
Author(s):  
K.P.D. Lagerlöf ◽  
A.H. Heuer ◽  
T.E. Mitchell
Keyword(s):  
Misfit Dislocation ◽  
Lattice Parameters ◽  
Dislocation Network ◽  
Misfit Dislocations ◽  
Space Group ◽  
Two Phases ◽  
Hematite Fe2o3

It has been reported by Lally et. al. [1] that precipitates of hematite (Fe2O3, space group R3c) in a matrix of ilmenite (FeTiO3, space group R3) are lens shaped and flattened along the [0001]-direction. The coherency across the interface is lost by the introduction of a misfit dislocation network, which minimizes the strain due to the deviation in lattice parameters between the two phases [2]. The purpose of this paper is to present a new analysis of this network.

Sign in / Sign up

Export Citation Format

Share Document