The crystal and molecular structure of tribromo-m-carborane

1976 ◽  
Vol 54 (11) ◽  
pp. 1771-1776 ◽  
Author(s):  
Alice Ann Sayler ◽  
Herbert Beall
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Electrophilic Substitution ◽  
Crystal And Molecular Structure ◽  
Structural Parameters ◽  
Bromine Atom ◽  
Theoretical Work ◽  
Crystal Data ◽  
The Third ◽  
The Subject

The sequence of electrophilic substitution for o- and m-carborane has been the subject of much experimental and theoretical work. The molecular structure of tribromo-m-carborane (m-B10Br3H7C2H2) shows that the third bromine atom to be substituted is found bonded to boron atom 12 (or 5). The crystal data are: space group, Pbcm; a = 8.47(4), b = 12.19(8), and c = 12.25(8) Å; ρo = 1.98(2) and ρc = 2.00 g/cm3 for Z = 4. Data were collected using Weissenberg geometry and Ni-filtered CuK, radiation. The visually estimated intensities of 920 reflections were used in the anisotropic block-diagonalized least-squares refinement of the 76 structural parameters. The final value of the conventional residual index was 0.087.

The crystal and molecular structure of dipyrrolidylthiuram disulfide

1983 ◽  
Vol 36 (7) ◽  
pp. 1371 ◽  
Author(s):  
GA Williams ◽  
JR Statham ◽  
AH White
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Dihedral Angle ◽  
Crystal And Molecular Structure ◽  
Structural Parameters ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray

The crystal structure of dipyrrolidylthiuram disulfide has been determined by single-crystal X-ray diffraction techniques at 295 K. Crystals are monoclinic, space group C2/c, unit cell a 13.835(3), b 10.422(2), c 9.427(3) �, β 97.08(2)� and Z 4. Automatic diffractometry has provided significant Bragg intensities for 1402 independent reflections, and the structure has been refined by least-squares methods to R 0.037. The structure consists of discrete C4H8NC(S)S2C(S)NC4H8 molecules. Half of each molecule is crystallographically unique with distances S-S 2.002(1), and C-S 1.804(2) and 1.645(2) �. The dihedral angle between planar C2NC(S)S portions is 87.9�. The relevance of the derived structural parameters to the question of why the tris(pyrrolidine-1-carbodithioato)iron(III) complex is, uniquely, high spin is discussed.

The crystal and molecular structure of 1,1-bis(diphenylphosphino)-2,2-dimethylhydrazine

1976 ◽  
Vol 54 (5) ◽  
pp. 738-743 ◽  
Author(s):  
J. Brian Faught
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Unit Cell ◽  
Space Group ◽  
Block Diagonal

The structure of 1,1-bis(diphenylphosphino)-2,2-dimethylhydrazine, [(C6H5)2P]2NN(CH3)2 has been determined crystallographically. The compound crystallizes from n-heptane in the space group P21/c with a = 8.910(1), b = 9.686(1), c = 27.489(4) Å, and β = 102.94(2)° with four molecules per unit cell. The structure was solved from 2669 independent reflections with I > 3σ(I) and refined by block diagonal least squares methods to R = 0.032 and Rω = 0.048. Each diphenylphosphino group is bonded to the same hydrazine nitrogen and the geometry about this nitrogen is nearly planar. The average dimensions of the structure are P—C = 1.828 ± 0.005, P—N = 1.715 ± 0.014, N—N = 1.451, and N—C = 1.457 ± 0.003 Å, [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text].

Crystal and molecular structure of 2,6-dimethyl-3,5-di[N-methyl]carbamoyl-4-[3,4-methoxy]phenyl-l,4-dihydropyridine hemihydrate and 2,6-dimethyl-3,5-di[N-methyl]carbamoyl-4-[furan]1,4-dihydropyridine

1999 ◽  
Vol 214 (12) ◽  
Author(s):  
M. Bidya Sagar ◽  
K. Ravikumar ◽  
Y. S. Sadanandam
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal Structures ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Asymmetric Unit ◽  
Full Matrix

AbstractThe crystal structures of two dihydropyridines were solved by direct methods and refined by full-matrix least-squares procedure. 2,6-Dimethyl-3,5-di[N-methyl]-carbamoyl-4-[3,4-methoxy]phenyl-1,4-dihydropyridine hemihydrate, CBoth compounds crystallize with two molecules in the asymmetric unit. In compound

Synthesis and molecular structure of tetraphenylarsonium Tetrakis(benzenethiolato)-oxorhenate(V)-Acetonitrile (1/1)

1983 ◽  
Vol 36 (2) ◽  
pp. 253 ◽  
Author(s):  
AC McDonell ◽  
TW Hambley ◽  
MR Snow ◽  
AG Wedd
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Crystal Data ◽  
Rhenium Atom ◽  
Space Group ◽  
X Ray ◽  
X Ray Crystallography

The salts Ph4As [ReO(SPh)4].MeCN and Ph4As [ReO(SePh)4] have been synthesized and characterized. The crystal and molecular structure of the thiolate compound has been determined by X-ray crystallography which reveals a square-pyramidal arrangement of ligand atoms around the central rhenium atom of the [ReO(SPh)4]- anion. Crystal data: a 9.756(4), b 18.171(3), c 25.684(4) �, space group P212121, Z 4.

The crystal and molecular structure of 4-Bromo-1,1,3,3,5,7,7,9,9-nonamethylbicyclo[4,4,0]pentaborophane

1975 ◽  
Vol 28 (6) ◽  
pp. 1187 ◽  
Author(s):  
GR Clark ◽  
GJ Palenik
Keyword(s):  
Molecular Structure ◽  
Bond Length ◽  
Crystal And Molecular Structure ◽  
Bromine Atom ◽  
Chair Conformation ◽  
Ring System ◽  
Intensity Data ◽  
Internal Ring ◽  
Charge Delocalization ◽  
Cyclic System

Crystals of 4-bromo-1,1,3,3,5,7,7,9,9- nonamethylbicyclo[4,4,0]pentaborophane, C9H35B5P5Br, are monoclinic, with a = 9.502(3), b = 20.185(15), c = 13.604(4) Ǻ, β = 116.49(2)�. The space group is P21/c, with four molecules in the cell. Intensity data were collected by means of an automated diffractometer. The atomic positions have been determined by least-squares refinement of 2859 observed reflections. The final residual, R, is 0.077. The molecule contains a framework of alternat- ing boron and phosphorus atoms constituting a decalin-like ring system. The two cis-fused cyclo- hexane type rings are both in the chair conformation. The bromine atom is equatorially bonded to the boron atom in the 4-position. The Br-B bond length is 2.039(10) Ǻ. The average P-B and P-C distances are 1.943 and 1.828 Ǻ respectively. Average internal ring angles are 112.2� for P-B-P, and 113.6� for B-P-B. This geometry indicates only very slight charge delocalization in the cyclic system.

The crystal structure of dibutyl-bis(pentamethylenedithiocarbamato)tin(IV)

1986 ◽  
Vol 51 (11) ◽  
pp. 2521-2527 ◽  
Author(s):  
Jan Lokaj ◽  
Eleonóra Kellö ◽  
Viktor Kettmann ◽  
Viktor Vrábel ◽  
Vladimír Rattay
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Least Squares ◽  
Coordination Polyhedron ◽  
Crystal And Molecular Structure ◽  
Distorted Octahedron ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray

The crystal and molecular structure of SnBu2(pmdtc)2 has been solved by X-ray diffraction methods and refined by a block-diagonal least-squares procedure to R = 0.083 for 895 observed reflections. Monoclinic, space group C2, a = 19.893(6), b = 7.773(8), c = 12.947(8) . 10-10 m, β = 129.07(5)°, Z = 2, C20H38N2S4Sn. Measured and calculated densities are Dm = 1.38(2), Dc = 1.36 Mg m-3. Sn atom, placed on the twofold axes, is coordinated with four S atoms in the distances Sn-S 2.966(6) and 2.476(3) . 10-10 m. Coordination polyhedron is a strongly distorted octahedron. Ligand S2CN is planar.

Crystal and molecular structure of [dimethyl(3,5-dimethyl-1-pyrazolyl)(ethanol-amino)gallato (N(2),O,N(3))](η3-cycloheptatrienyl)dicarbonylmolybdenum

1981 ◽  
Vol 59 (11) ◽  
pp. 1665-1670 ◽  
Author(s):  
Kenneth S. Chong ◽  
Steven J. Rettig ◽  
Alan Storr ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Amino Nitrogen ◽  
Full Matrix ◽  
Octahedral Environment ◽  
Distorted Octahedral ◽  
Unusual Type

Crystals of [dimethyl(3,5-dimethyl-l-pyrazolyl)(ethanolamino)gallato(N(2),O,N(3))](η3-cycloheptatrienyl)dicarbonylmolybdenum are monoclinic, a = 10.511(1), b = 8.335(1), c = 24.138(3) Å, β = 102.22(1)°, Z = 4, space group P21/c. The structure was solved by Patterson and Fourier syntheses and was reflned by full-matrix least-squares procedures to R = 0.028 and Rw = 0.046 for 3708 reflections with I ≥ 3σ(I). The crystal structure consists of discrete molecules linked by N—H … O hydrogen bonds (N … O = 2.929(5) Å). The Mo atom is in a distorted octahedral environment with the η3-C7H7 ligand occupying one coordination site, trans to the amino nitrogen, as a π-donating ligand. Important bond distances (corrected for libration) are: Mo—O, 2.245(2), Mo—N(amino), 2.249(3), Mo—N(pyrazolyl), 2.270(3), Mo—C(O), 1.950(4) and 1.947(4), Mo—C(C7H7), 2.176(4), 2.364(4), and 2.380(4), Ga—O, 1.919(3), Ga—N, 1.984(3), and Ga—C, 1.982(5) and 1.983(5) Å. An unusual type of disorder is present in which a second image of the molecule, approximately mirrored by the plane y = 1/4, is in evidence at low occupancy.

Spaltung von S4N4 zu S2N2 bei Raumtemperatur: Darstellung und Struktur von S2N2 • 2AlBr3 / Cleavage of S4N4 to S2N2 at Room Tem perature: Preparation and Structure of S2N2 • 2AlBr3

1984 ◽  
Vol 39 (2) ◽  
pp. 145-148 ◽  
Author(s):  
Ulf Thewalt ◽  
Konrad Holl
Keyword(s):  
Molecular Structure ◽  
Room Temperature ◽  
Crystal And Molecular Structure ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Lengths

The compound S2N2 • 2AlBr3 has been prepared by reaction of S4N4 with AlBr3 in 1,2-dibromoethane at room temperature. Its crystal and molecular structure have been determined by X-ray diffraction; R = 0.068. Crystal data: monoclinic, P 21/n, a = 9.594(5), b = 9.975(4), c = 7.528(4) Å , β = 111.36(5)°. The S2N2 ring of the centrosymmetrical complex is bonded via its nitrogen atoms to two AlBr3 units thus completing coordination tetrahedra around the Al atoms. Bond distances and angles within the S2N2 ring are d(S-N) = 1.629(13) and 1.651(13) Å, ∢ (S-N-S) = 95.8, and ∢ (N-S-N) - 84.2°. Whereas the S-N bond lengths agree closely with those of free S2N2, the angle at N is enlarged by ca. 5° and the angle at S is decreased by ca. 5°. The sulfur atoms form two close S···Br contacts of length 3.149 (intramolecular) and 3.193 (intermolecular) Å , respectively. The intermolecular attractive nonbonded S···Br interactions tie the complexes together in a way that leads to infinite chains which run parallel to the crystallographic z axis

The crystal and molecular structure of anti-1,2,4,5-tetraphenyl-3,6-dicarbomethoxytricyclo[3.1.0.02,4]hexane

1978 ◽  
Vol 56 (10) ◽  
pp. 1364-1367 ◽  
Author(s):  
M. J. Bennett ◽  
J. T. Purdham
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Experimental Error ◽  
Crystal And Molecular Structure ◽  
Structural Data ◽  
Monoclinic Space Group ◽  
Full Matrix ◽  
Bond Lengths ◽  
Highly Strained ◽  
Least Squares Techniques

1,2,4,5-Tetraphenyl-3,6-dicarbornethoxytricyclo[3.1.0.02,4]hexane crystallizes in the monoclinic space group P21/c with a = 10.044(4), b = 9.500(2), c = 14.172(4) Å, β = 104.38(2)°, and Z = 2. Using 1032 unique reflections with I > 3σ(I), the structural data were refined by full matrix least-squares techniques to R = 0.038. The molecule was found to be in the anti-configuration. All bond lengths within the highly strained central tricyclic framework were equal within experimental error and average 1.531 Å.

Reaction of N,N′-dihydroxy-.N,N′-dimethylmethanediamine with phenylboronic acid and the crystal and molecular structure of N,N′-dihydroxy-N,N′-dimethylmethanediamine

1989 ◽  
Vol 67 (11) ◽  
pp. 1959-1963 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Phenylboronic Acid ◽  
Direct Methods ◽  
Exact Formula ◽  
Full Matrix ◽  
Space Group ◽  
Hydrogen Bonded

The reaction of N,N′-dihydroxy-N,N′-dimethylmethanediamine with phenylboronic acid leads to the product 1,7-dimethyl-3,5-diphenyl-2,4,6-trioxa-7-aza-1-azonia-3-bora-5-boratabicyclo[3.3.0]octane rather than the expected product 1,5-dimethyl-3-phenyl-1,5-diaza-2,4-dioxa-3-boracyclohexane. The structure of N,N′-dihydroxy-N,N′-dimethylmethanediamine has been determined and is discussed in terms of its reaction with PhB(OH)2. Crystals of N,N′-dihydroxy-N,N′-dimethylmethanediamine are tetragonal, a = 8.5346(3), c = 8.4178(7) Å, Z = 4, space group P421c. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.036 and Rw of 0.038 for 333 reflections with I ≥ 3σ(I). The structure consists of hydrogen-bonded dimers having exact [Formula: see text] symmetry. Keywords: N,N′-dihydroxy-N,N′-dimethylmethanediamine, crystal structure.

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