scholarly journals The structure of polyisoprenes. VI An investigation of the molecular structure of dibenzyl by X-ray analysis

1947 ◽  
Vol 188 (1013) ◽  
pp. 222-236 ◽  
Keyword(s):  
Molecular Structure ◽  
Standard Length ◽  
Three Dimensional ◽  
Intermolecular Forces ◽  
The Other ◽  
X Ray ◽  
Bond Lengths ◽  
Benzene Rings ◽  
Carbon Bonds ◽  
Atomic Parameters

The molecular structure of dibenzyl has been determined to an accuracy of about 0.01A by using extensive X-ray data in three-dimensional Fourier syntheses to refine the approximate atomic parameters originally derived by Robertson. The three formally single-carbon bonds joining the benzene rings have lengths of 1.50, 1.48 and 1.50A and make angles of 115° with each other. The departure from the standard length of 1.54A is discussed in relation to the analogous systems of polyisoprenes and 1.5 dienes where related effects have been observed. The dimensions of the benzene rings also reflect the unusual character of the acyclic carbon bonds, two of the aromatic bond lengths being 1.39A and the other four 1.37A. The molecule, although possessing a centre of symmetry, is not absolutely symmetrical, since the central CH 2 — CH 2 bond is inclined at 70.5° to the plane of the benzene rings. This is ascribed to the influence of intermolecular forces.

scholarly journals 3-[2-(Triphenylphosphanylidene)acetyl]-2H-chromen-2-one

2013 ◽  
Vol 69 (2) ◽  
pp. o245-o245
Author(s):  
Muhammad Taha ◽  
Nor Hadiani Ismail ◽  
Ahmad Nazif Aziza ◽  
Syed Adnan Ali Shah ◽  
Sammer Yousuf
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Three Dimensional ◽  
Bond Lengths ◽  
Compound C ◽  
Benzene Rings ◽  
Graph Set ◽  
Ring Motif

In the title compound, C29H21O3P, a coumarin-substitued ylid, the P atom is linked to three benzene rings and a planar coumarin moietyviaa methylenecarbonyl group. The bond lengths in the P=C–C=O fragment clearly indicate a delocalized system involving the olefinic and carbonyl bonds. The molecular structure is stabilized by an intramolecular C—H...O interaction that results in anS7 graph-set ring motif. In the crystal, molecules are linked into a three-dimensional framework by C—H...O hydrogen bonds.

The crystallography and molecular structure of 1, 8-bisdehydro-[14]annulene

1966 ◽  
Vol 290 (1420) ◽  
pp. 94-114 ◽  
Keyword(s):  
Molecular Structure ◽  
Three Dimensional ◽  
Hydrogen Atoms ◽  
Carbon Bond ◽  
X Ray ◽  
Bond Lengths ◽  
Difference Density ◽  
Carbon Carbon Bond ◽  
The Difference ◽  
Better Than

A three-dimensional X-ray analysis of the crystal and molecular structure of 1,8-bisdehydro- [14]annulene, C 14 H 10 , is described. Carbon-carbon and carbon-hydrogen bond lengths have average estimated standard deviations of 0.009 and 0.06 Ǻ respectively and are discussed in the light of molecular orbital predictions of the electron density in the molecule; the root mean square agreement between observed and calculated carbon-carbon bond lengths is better than 0.01 Ǻ. Distortions of the carbon bond angles from strict trigonal and digonal symmetry are attributed to intramolecular steric interactions between hydrogen atoms and carbon or other hydrogen atoms. An analysis of the molecular vibrations in the lattice shows the three r.m.s. translational amplitudes about the molecular symmetry axes to be 0.18, 0.19, 0.18 Ǻ, the three corresponding r.m.s. librational amplitudes being 2.9, 2.2 and 3.6°. The ‘difference' density syntheses (σ = 0.06 e/Ǻ 3 ) are discussed and the crystal structure is related to anthracene and phenanthrene, isomers of bisdehydro-[14]annulene.

The Crystal and Molecular Structure of Dichloro(acetylacetonato)-2,2′-bipyridylindium(III)

1974 ◽  
Vol 52 (22) ◽  
pp. 3793-3798 ◽  
Author(s):  
J. G. Contreras ◽  
F. W. B. Einstein ◽  
D. G. Tuck
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Three Dimensional ◽  
Space Group ◽  
X Ray ◽  
Bond Lengths ◽  
R Factor ◽  
Chloride Ligands ◽  
Least Squares Techniques

The molecular structure of dicholoro(acetylacetonato)-2,2′-bipyridylindium(III) has been determined from three dimensional X-ray data collected by counter methods. The structure has been refined by least-squares techniques to a conventional R factor of 4.3% for the 3524 observed reflections. Crystals of Cl2In(acac)(bipy) are monoclinic, a = 11.340(3), b = 12.198(3), c = 14.330(3) Å, β = 120.25(2)°, z = 4, space group P21/c. The chloride ligands are cis, with In—Cl at distances of 2.443(1) and 2.394(1) Å; the In—O bond lengths are 2.124(3) and 2.164(3) Å, and the In—N bond distances are 2.276(4) and 2.299(4) Å.

scholarly journals Crystal structure of 4-({5-[(E)-(3,5-difluorophenyl)diazenyl]-2-hydroxybenzylidene}amino)-2,2,6,6-tetramethylpiperidin-1-oxyl

2015 ◽  
Vol 71 (7) ◽  
pp. 864-866
Author(s):  
Ramazan Tatsız ◽  
Veli T. Kasumov ◽  
Tuncay Tunc ◽  
Tuncer Hökelek
Keyword(s):  
Dihedral Angle ◽  
Three Dimensional ◽  
Chair Conformation ◽  
The Other ◽  
Supramolecular Network ◽  
Stacking Interactions ◽  
Asymmetric Unit ◽  
Compound C ◽  
Benzene Rings ◽  
Independent Molecules

The asymmetric unit of the title compound, C22H25F2N4O2, contains two crystallographically independent molecules. In one molecule, the two benzene rings are oriented at a dihedral angle of 1.93 (10)° and in the other molecule the corresponding dihedral angle is 7.19 (9)°. The piperidine rings in the two molecules adopt a similar distorted chair conformation, and both have pseudo-mirror planes passing through the N—O bonds. An intramolecular O—H...N hydrogen bond between the hydroxy group and the imine N atom is observed in both molecules. In the crystal, weak C—H...O and C—H...F hydrogen bonds, enclosingR22(6) ring motifs, and weak π–π stacking interactions link the molecules into a three-dimensional supramolecular network, with centroid-to-centroid distances between the nearly parallel phenyl and benzene rings of adjacent molecules of 3.975 (2) and 3.782 (2) Å.

scholarly journals X-Ray Single Crystal Structural Analysis of Magnetically Oriented Microcrystals

2014 ◽  
Vol 70 (a1) ◽  
pp. C1138-C1138
Author(s):  
Chiaki Tsuboi ◽  
Kazuki Aburaya ◽  
Shingo Higuchi ◽  
Fumiko Kimura ◽  
Masataka Maeyama ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Single Crystal ◽  
Three Dimensional ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Data Set ◽  
Uv Curable ◽  
X Ray

We have developed magnetically oriented microcrystal array (MOMA) technique that enables single crystal X-ray diffraction analyses from microcrystalline powder. In this method, microcrystals suspended in a UV-curable monomer matrix are there-dimensionally aligned by special rotating magnetic field, followed by consolidation of the matrix by photopolymerization. From thus achieved MOMAs, we have been succeeded in crystal structure analysis for some substances [1, 2]. Though MOMA method is an effective technique, it has some problems as follows: in a MOMA, the alignment is deteriorated during the consolidation process. In addition, the sample microcrystals cannot be recovered from a MOMA. To overcome these problems, we performed an in-situ X-ray diffraction measurement using a three-dimensional magnetically oriented microcrystal suspension (3D MOMS) of L-alanine. An experimental setting of the in-situ X-ray measurement of MOMS is schematically shown in the figure. L-alanine microcrystal suspension was poured into a glass capillary and placed on the rotating unit equipped with a pair of neodymium magnets. Rotating X-ray chopper with 10°-slits was placed between the collimator and the suspension. By using this chopper, it was possible to expose the X-ray only when the rotating MOMS makes a specific direction with respect to the impinging X-ray. This has the same effect as the omega oscillation in conventional single crystal measurement. A total of 22 XRD images of 10° increments from 0° to 220° were obtained. The data set was processed by using conventional software to obtain three-dimensional molecular structure of L-alanine. The structure is in good agreement with that reported for the single crystal. R1 and wR2 were 6.53 and 17.4 %, respectively. RMSD value between the determined molecular structure and the reported one was 0.0045 Å. From this result, we conclude that this method can be effective and practical to be used widely for crystal structure analyses.

Crystal and Molecular Structure of 3-Iodo-2-propynyl-N-butylcarbamate

1997 ◽  
Vol 52 (2) ◽  
pp. 256-258 ◽  
Author(s):  
Evgeni V. Avtomonov ◽  
Rainer Grüning ◽  
Jörg Lorberth
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Title Compound ◽  
Crystal And Molecular Structure ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dimensional Network ◽  
Carbamate Group ◽  
Oxygen Atoms

Abstract The crystal structure of the title compound has been determined by X-ray diffraction methods. Due to the Lewis acidic character of the iodine substituent a “zig-zag” chain is formed via intermolecular interactions (2.933(4) A) between iodine and oxygen atoms of theocarbamate moiety. A three-dimensional network is formed through hydrogen-bridging (2.04 A) between NH-groups and the oxygen atoms of the neighbouring carbamate group of the next molecule.

Structural Systematics of 2/4-Nitrophenoxide Complexes of Closed-Shell Metal Ions. VII Acid Salts of the 4-Nitrophenoxides of Group 2

1998 ◽  
Vol 51 (8) ◽  
pp. 785 ◽  
Author(s):  
Jack M. Harrowfield ◽  
Raj Pal Sharma ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Room Temperature ◽  
Calcium Salt ◽  
Three Dimensional ◽  
Closed Shell ◽  
The Other ◽  
X Ray ◽  
C 23 ◽  
Structure Determinations ◽  
Group 2 ◽  
Acid Salts

Room-temperature single-crystal X-ray structure determinations are recorded for a number of Group 2 4-nitrophenoxide acid salts, variously hydrated M(4-np)2.x(4-npH).yH2O. Ca(4-np)2.2(4-npH).8H2O is monoclinic, P 21/n, a 30·52(1), b 10·027(1), c 23·65(2) Å, β 116·3(5)°, Z = 8, conventional R on |F| being 0·058 for No 5092 independent ‘observed’ (I > 3s(I)) reflections. Sr(4-np)2.2(4-npH).8H2O, based on a subcell of the former, is monoclinic, P 21/c, a 15·576(5), b10·081(6), c 24·20(2) Å, β 117·99(5)° , Z = 4, R 0·054 for No 2908. Ba(4-np)2.2(4-npH).4H2O is orthorhombic, Fdd2, a 28·01(1), b 19·90(1), c 10·692(7)Å, Z = 8, R 0·028 for No 1967. The strontium array (and that of the calcium salt developed from it) may be represented as [(H2O)6Sr(4-npH.4-np)] (4-npH.4-np), a neutral ligand being unsymmetrically chelated to the strontium through the nitro group, with a quasi-parallel counter ion hydrogen-bonded to it by phenoxide confrontation. The other two 4-np residues make up a similar phenoxide-confronting pair (4-npH.4-np), the hydrogen being more intimately associated with one moiety. The barium salt is also an interesting array: the 10-coordinate barium lies on a crystallographic 2 axis, in an environment of two pairs of symmetry-related nitro-chelating ligand anions, and a pair of nitro-O coordinating neutral 4-npH ligands; the whole [(H2O)4Ba(4-np)2(4-npH)2] array may be envisaged as a single neutral (super)molecule. Hydrogen bonds between confronting phenoxides of the neutral 4-npH components of the parent and the 4-np- components of neighbouring molecules link the whole into a three-dimensional array.

scholarly journals IX—investigations on magne-crystallic action III—Further studies on organic crystals

1935 ◽  
Vol 234 (739) ◽  
pp. 265-298 ◽  
Keyword(s):  
Molecular Structure ◽  
Crystal Lattice ◽  
Convenient Method ◽  
Organic Crystals ◽  
Double Refraction ◽  
Magnetic Susceptibilities ◽  
X Ray ◽  
Benzene Rings ◽  
The Individual ◽  
Ray Methods

In Part I* of this paper a convenient method of measuring the principal magnetic susceptibilities of single crystals was described, and several organic crystals, among others, were studied by this method. The results were discussed particularly in relation to the structure of the molecules and their orientations in the crystal lattice, and it was shown how a correlation of the principal magnetic susceptibilities of the crystal with those for the individual molecules (obtained from measurements on magnetic double-refraction in the liquid state, or from considerations of molecular structure) gives us useful information regarding the orientations of the molecules in the crystal lattice. Indeed, in favourable cases the molecular orientations may thus be determined much more easily, and some of the parameters defining the orientations also more accurately, than by X-ray methods of analysis. Conversely, where the molecular orientations in the crystal lattice are already known from X-ray studies, a knowledge of the principal magnetic susceptibilities of the crystal enables us to obtain the magnetic constants of the individual molecules, which are of interest. For example, it is thus found that as one proceeds from benzene to naphthalene and from naphthalene to anthracene, the numerical increase in susceptibility that occurs, is directed predominantly along the normal to the plane of the benzene rings

A novel dinuclear bismuth(III) coordination compound: bis(μ-pyridine-2,6-dicarboxylato)-κ4O2,N,O6:O6′;κ4O2:O2′,N,O6-bis[(azido-κN)(1,10-phenanthroline-κ2N,N′)bismuth(III)] tetrahydrate

2014 ◽  
Vol 70 (6) ◽  
pp. 562-565 ◽  
Author(s):  
Wei Zhang ◽  
Yu-Quan Feng
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonds ◽  
Coordination Compound ◽  
Photoelectron Spectroscopy ◽  
Three Dimensional ◽  
Water Molecules ◽  
Stacking Interactions ◽  
Coordination Geometry ◽  
X Ray Diffraction ◽  
X Ray

A novel dinuclear bismuth(III) coordination compound, [Bi2(C7H3NO4)2(N3)2(C12H8N2)2]·4H2O, has been synthesized by an ionothermal method and characterized by elemental analysis, energy-dispersive X-ray spectroscopy, IR, X-ray photoelectron spectroscopy and single-crystal X-ray diffraction. The molecular structure consists of one centrosymmetric dinuclear neutral fragment and four water molecules. Within the dinuclear fragment, each BiIIIcentre is seven-coordinated by three O atoms and four N atoms. The coordination geometry of each BiIIIatom is distorted pentagonal–bipyramidal (BiO3N4), with one azide N atom and one bridging carboxylate O atom located in axial positions. The carboxylate O atoms and water molecules are assembledviaO—H...O hydrogen bonds, resulting in the formation of a three-dimensional supramolecular structure. Two types of π–π stacking interactions are found, with centroid-to-centroid distances of 3.461 (4) and 3.641 (4) Å.

Structure cristalline et moléculaire du cyclopentadiényle dicarbonyle triphénylphosphine manganèse, MnC5H5(CO)2P(C6H5)3

1973 ◽  
Vol 51 (18) ◽  
pp. 3027-3031 ◽  
Author(s):  
Claude Barbeau ◽  
Klaus Sorrento Dichmann ◽  
Louis Ricard
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Least Squares Method ◽  
Three Dimensional ◽  
Triphenyl Phosphine ◽  
Triclinic Space Group ◽  
Space Group ◽  
Bond Lengths ◽  
Atomic Parameter

The crystalano molecular structure of cyclopentadienyl manganese dicarbonyl-triphenyl phosphine has been determined by means of three dimensional data obtained by a Buerger precession camera. 2931 independent intensities were utilized in the refinement of the structure using the least-squares method. The final disagreement factor is 0.11. MnC5H5(CO)2P(C6H5)3 crystallizes in the triclinic space group.[Formula: see text]The molecule shows atomic parameter almost identical to those of MnC5H5(CO)3 except for the Mn—C bond lengths which change from 1.80 to 1.73 Å. The Mn—P distance (2.236 Å) and the unchanged parameters for the Mn—C5H5 group confirm the strong donating power of the cyclopentadienyl group. [Journal translation]

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