The crystal and molecular structure of quaterrylene

1960 ◽  
Vol 257 (1291) ◽  
pp. 477-490 ◽  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Current Theory ◽  
Mean Value ◽  
Unit Cell ◽  
Two Dimensional ◽  
Monoclinic System ◽  
Space Group ◽  
The Mean

Quaterrylene (III) is isotypic with perylene (I); it crystallizes in the monoclinic system with a = 11·25, b = 10·66, c = 19·31 Å, β = 100·6°, and with four molecules per unit cell and the space group P 2 1 / a . The crystal structure has been determined by two-dimensional methods. In the b -axial projection a majority of the carbon atoms are resolved, and, since the molecule lies with its greatest length almost exactly perpendicular to this axis, the lengths of the peri -bonds connecting the naphthalenic residues have been determined with moderate accuracy. The mean value is assessed at 1·53 ± 0·01 Å, which is significantly larger than current theory predicts. Possible reasons for this difference are discussed.

Crystal and molecular structure of the nickel(II) chelate of salicylidenethiosemicarbazone ammine - C8H7N3OSNi.NH3

1981 ◽  
Vol 46 (4) ◽  
pp. 975-981 ◽  
Author(s):  
Eduard Gyepes ◽  
František Pavelčík ◽  
Anton Beňo
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Specific Weight ◽  
Unit Cell ◽  
Lattice Parameters ◽  
Monoclinic System ◽  
Space Group ◽  
Symmetry Space ◽  
Symmetry Space Group

The nickel(II) chelate of salicylidenethiosemicarbazone ammine-C8H7N3OSNi.NH3 crystallizes in a monoclinic system. The lattice parameters are: a = 6.857(2), b = 9.763(2), c = 15.340(4) .10-10 m, β = 90.34(2)° and the volume of the unit cell V = 1027(1) . 10-30 m3; the specific weight was measured as dm = 1.76 Mg m-3 and calculated as dc = 1.74 Mg m-3. The number of formula units in the unit cell, Z = 4, and the symmetry space group is P21/c.

The crystal and molecular structure of aqua-bis(ethylenediamine)cupric-tris(cyano)-selenocyanatodicuprate

1982 ◽  
Vol 47 (10) ◽  
pp. 2623-2632 ◽  
Author(s):  
Viktor Vrábel ◽  
Jan Lokaj ◽  
Ján Garaj ◽  
František Pavelčík
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Structural Analysis ◽  
Least Squares Method ◽  
Crystal And Molecular Structure ◽  
Three Dimensional ◽  
Monoclinic System ◽  
Space Group ◽  
X Ray ◽  
Triclinic System

The crystal structure of [Cu(H2O)(en)2][Cu2(CN)3(SeCN)] was solved by single crystal X-ray structural analysis in the triclinic system with a space group of P1 and in the monoclinic system with a space group of C2. In the triclinic system the unit cell has dimensions of a = 0.8445(3), b = 0.7903(3), c = 0.8444(3) nm, α = 119.58(2), β = 118.59(2) and γ = 93.63(3)° and, in the monoclinic system, a = 1.3331(4), b = 0.8670(2), c = 0.8267(3), β = 122.60(2)°. The structure was refined by the least squares method to final value of R = 5.5% in the triclinic system and R = 7.8% in the monoclinic system. The coordination sphere around the Cu(II) atom is square pyramidal, formed of two ethylenediamine molecules and one water molecule. The Cu(I) atoms are tetrahedrally coordinated by bridging SeCN and CN ligands to form infinite three-dimensional chains. The SeCN group is bonded to the Cu(I) atoms through the Se atom at distances of 0.2731(3) and 0.2745(3) nm.

The crystal and molecular structure of fluorene

1955 ◽  
Vol 227 (1169) ◽  
pp. 200-214 ◽  
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Experimental Error ◽  
Crystal And Molecular Structure ◽  
Unit Cell ◽  
Carbon Skeleton ◽  
Two Dimensional ◽  
Trial And Error ◽  
Orthorhombic System ◽  
Space Group

Fluorene, C 13 H 10 , crystallizes in the orthorhombic system, space group Pnam with four molecules per unit cell. The molecule possesses a plane of symmetry which is parallel to the (001) plane of the crystal. The structure has been determined by trial-and-error methods, followed (i) by a least-squares refinement and (ii) by two-dimensional Fourier syntheses. The results from the two methods of refinement are compared and for (ii) a method is given for systematically correcting for overlapping of atoms in projections. The accuracy of the co-ordinates given by these methods is discussed in detail, and it is concluded that the co-ordinates adopted are correct to ±0.017 Å. The carbon skeleton is planar to within the experimental error and the equation of the plane is y = 1.4375 x + 11.0947.

Notizen: Kristall- und Molekülstruktur von (1-Diphenylphosphoryl-1 H-trifluormethyl)-diphenylphosphinat1 / Crystal and Molecular Structure of (1-Diphenylphosphoryl-1 H-trifluoromethyl)-diphenylphosphinate1

1977 ◽  
Vol 32 (6) ◽  
pp. 707-708 ◽  
Author(s):  
Sigurd Hoehne ◽  
Hans Lesiecki ◽  
Hans-Dieter Ebert ◽  
Ekkehard Lindner ◽  
Joachim Strähle
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Unit Cell ◽  
Space Group ◽  
Centrosymmetric Space Group ◽  
R Value

(1 - Diphenylphosphoryl -1 H - trifluoromethyl)-diphenylphosphinate crystallizes monoclinic in the centrosymmetric space group P21/c with 4 molecules in the unit cell. The crystal structure was refined to a R value of 0.027.

Crystal and molecular structure of fenspiride, C15H20N2O2

2020 ◽  
Vol 35 (2) ◽  
pp. 144-146
Author(s):  
Silvina Pagola
Keyword(s):  
Molecular Structure ◽  
General Position ◽  
Crystal And Molecular Structure ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Monoclinic System ◽  
Inflammatory Drug ◽  
Space Group ◽  
Cell Parameters ◽  
Independent Molecules

The crystal and molecular structure of fenspiride, a bronchodilator and anti-inflammatory drug, are reported. Fenspiride crystallizes in the monoclinic system, with two crystallographically independent molecules in the general position of the space group P21/n (No. 14) and Z = 8. Rietveld refined unit cell parameters are a = 11.52013(8) Å, b = 5.614091(31) Å, c = 44.1567(4) Å, α = 90°, β = 93.0885(6)°, γ = 90°, and V = 2851.69(4) Å3.

Crystal and molecular structure of dodecamethylcyclohexaphosphazene, (NPMe2)6

1977 ◽  
Vol 55 (17) ◽  
pp. 3118-3123 ◽  
Author(s):  
Richard T. Oakley ◽  
Norman L. Paddock ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Unit Cell ◽  
Weighted Mean ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
The Mean

Crystals of dodecamethylcyclohexaphosphazene are triclinic, a = 13.898(1), b = 8.690(1), c = 10.790(1) Å, α = 109.84(1), β = 92.01(1), γ = 106.39(1)°, Z = 2, space group [Formula: see text]. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.034 and Rw of 0.042 for 4217 reflections with I ≥ 3σ(I). The unit cell contains two independent centrosymmetric molecules which are virtually identical. The 12-membered rings have the 'double tub' conformation. Bond lengths not involving hydrogen have been corrected for libration. Weighted mean bond lengths (rms deviations from the mean in parentheses) are: P—N, 1.593(6), C—P, 1.808(4), and C—H, 0.95(6) Å.

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].

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.

Metalltetrahydridoborate und Tetrahydridometallate, 11 [1] Zur Kristall- und Molekülstruktur von Magnesiumtetrahydridoborat Mg(BH4)2 • 3 THF / Metal Tetrahydridoborates and Tetrahydridoborato Metallates, 11 [1] The Crystal and Molecular Structure of Magnesium Tetrahydridoborate Mg(BH4)2 • 3 THF

1982 ◽  
Vol 37 (12) ◽  
pp. 1499-1503 ◽  
Author(s):  
Heinrich Nöth
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Oxygen Atom ◽  
Coordination Polyhedron ◽  
Crystal And Molecular Structure ◽  
Equatorial Position ◽  
Crystallographic Axis ◽  
Space Group ◽  
Distorted Trigonal Bipyramid ◽  
Double Hydrogen

Mg(BH4)2 • 3 THF was prepared from MgHo and B2H6 in tetrahydrofuran. It crystallizes monoclinically, space group C2/c, Z = 4. The crystal structure reveals that the molecule contains a seven-coordinate Mg center. Its BH4 groups form double hydrogen bridges to magnesium. The geometry at Mg corresponds to a slightly distorted trigonal bipyramid for the O 3 B 2 (Mg)-coordination polyhedron, with two THF molecules in apical and one in equatorial position. A two-fold crystallographic axis passes through Mg and the equatorial oxygen atom thus posing C2 symmetry on the molecule

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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