The crystal structure of a chiral m-cyclophane

1985 ◽  
Vol 63 (12) ◽  
pp. 3298-3304 ◽  
Author(s):  
T. H. Chan ◽  
G. J. Kang ◽  
F. Belanger-Gariepy ◽  
F. Brisse ◽  
K. Steliou
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Molecular Mechanics ◽  
Absolute Configuration ◽  
Direct Methods ◽  
Membered Ring ◽  
Molecular Mechanics Calculations ◽  
Orthorhombic System ◽  
X Ray ◽  
System A

The crystal structure of a chiral m-cyclophane, the α-isomer of (S)-α-methoxy-α-(trifluoromethyl)phenylacetate ester of 13-(methoxycarbonyl)-14-hydroxy-17-methyl-[11]-m-cyclophane (C30H37O5F3, FW = 534.62) has been solved by direct methods and refined by a least-squares procedure to a final R = 0.048 for 2756 independent reflections. The crystals belong to the orthorhombic system, a = 10.8077(13), b = 13.676(3), c = 19.060(4) Å, V = 2817.2 Å3, Z = 4, and the space group is P212121. The absolute configuration of the chiral plane, using the S-configuration of the α-methoxy-α-(trifluoromethyl)phenylacetate ester as reference, is found to be S, in agreement with the X-ray result. The 14-membered ring has the slightly distorted rectangular conformation that has been described by Dale as the rectangular diamond-lattice conformation [3434]. The distortions, also observed in similar 14-membered rings, have been successfully approximated by molecular mechanics calculations.

Beiträge zur Strukturchemie phosphorhaltiger Ketten und Ringe, IX [1]. Die Molekül- und Kristallstruktur von Tri-tert-butylcyclotriphosphanpentacarbonyl- chrom(O), [(t-BuP)3Cr(CO)5] / Structural Chemistry of Phosphorus-Containing Chains and Rings, IX [1]. The Molecular and Crystal Structure of Tri-tert-butylcydotriphosphane-pentacarbonyl-chromium (0), [(t-BuP)3Cr(CO)5]

1984 ◽  
Vol 39 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Karl-Friedrich Tebbe ◽  
Magda Fehér
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Direct Methods ◽  
Membered Ring ◽  
Free Molecule ◽  
Donor Ligand ◽  
Space Group ◽  
X Ray ◽  
Phosphorus Containing

The structure of [(t-BuP)3Cr(CO)5], C17CrH27O5P3, has been determined by single crystal X-ray techniques, solved by ‘direct methods', and refined to R = 0.048, wR = 0.050 for 3657 reflections by blocked least squares. The compound crystallizes in the space group P 21/c with a = 1664.9 pm, b = 916.5 pm , c = 3089.8 pm, β= 91.45° and Z = 8 formula units. The structure consists of two crystallographically independent but structurally nearly identical mononuclear [(t-BuP)3Cr(CO)5] complexes with the three-membered ring (t-BuP)3 as an unidentate σ-donor ligand. Compared to the free molecule (t-BuP)3 the cyclophosphane ligand is slightly distorted on account of its coordination to the Cr(CO)5-group.

scholarly journals Crystal Structure of Poly[(acetone-O)-3-((3,4-dimethoxyphenyl)(4-hydroxy-2-oxo-2H-chromen-3-yl)methyl)-(2-oxo-2H-chromen-4-olate)sodium]

2010 ◽  
Vol 2010 ◽  
pp. 1-7
Author(s):  
Anita Penkova ◽  
Pascal Retailleau ◽  
Ilia Manolov
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Direct Methods ◽  
Orthorhombic System ◽  
Full Matrix ◽  
X Ray ◽  
X Ray Crystallography

The structure of Poly[(acetone-O)-3-((3,4-dimethoxyphenyl)(4-hydroxy-2-oxo-2H-chromen-3-yl)methyl)-(2-oxo-2H-chromen-4-olate)sodium] was determined by X-ray crystallography. The compound crystallizes in an orthorhombic system and was characterized thus P 21 21 21, a=9.967(2) Å, b=11.473(3) Å, c=22.176(5) Å. Z=4, V=2535.9(10) Å3. The crystal structure was solved by direct methods and refined by full-matrix least-squares on F2 to final values of R1=0.0601 and wR2=0.1515.

7α-Acetoxydihydronomilin: isolation, spectra, and crystal structure

1978 ◽  
Vol 56 (7) ◽  
pp. 1020-1025 ◽  
Author(s):  
Farid R. Ahmed ◽  
Angs Ng ◽  
Alex G. Fallis
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Least Squares ◽  
Furan Ring ◽  
Lactone Ring ◽  
Direct Method ◽  
Membered Ring ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray ◽  
Twist Boat

Methanol extraction of the ground seeds of Uncaria Gambier Roxb. followed by chromatography afforded a crystalline C30H38O10 terpene. This has been shown by X-ray analysis to be 7α-acetoxydihydronomilin. The crystals are orthorhombic, P212121, a = 13.158(2), b = 17.092(2), c = 12.689(2) Å, Z = 4, dx = 1.300, do = 1.300 g cm−3. The structure has been determined by the direct method and Fourier syntheses, and refined by block-diagonal least-squares to R = 0.042 for 2621 observed reflexions. The molecule contains a seven-membered lactone ring A, three six-membered rings B, C, D, a three-membered ring E, a furan ring F, and two acetate groups. A and B are chair, C is twist-boat, D is 1,3-diplanar, while E and F are planar. The A/B, A/C, C/D junctions are trans, D/E is cis, and F is linked to D by an equatorial C—C bond. The two acetate groups are in axial positions on A and B and are cis to each other. The O atom forming the apex of the three-membered ring is wedged between two H atoms and their parent C atoms at short intramolecular distances O … H = 2.28(2) and 2.28(3), and O … C = 2.623(3) and 2.668(4) Å. No intermolecular hydrogen bonding is indicated.

Crystal structure of cis-Tetracarbonylbis(chloromercury)iron

1976 ◽  
Vol 29 (9) ◽  
pp. 1905 ◽  
Author(s):  
CL Raston ◽  
AH White ◽  
SB Wild
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Diffraction Data ◽  
Title Compound ◽  
Direct Methods ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Independent Molecules

The crystal structure of the title compound has been determined by direct methods from X-ray diffraction data and refined by least squares to a residual of 0.071 for 2647 'observed' reflections. Crystals are monoclinic, C2/c, a = 36.81(1), b = 11.181(2), c = 20.369(5) �, β = 95.28(3)�, Z = 32. There are four independent molecules in the asymmetric unit, all with the cis disposition of ligands (<Fe-Hg), 2.498 �; <Hg-Fe-Hg), 80.9�); in one of the molecules one of the carbonyl sites is occupied by a more substantial moiety, possibly a result of partial occupancy of HgCl as a result of disorder or decomposition.

scholarly journals The reaction of 3,5-diphenyl-1,2-dithiolium-4-olate with aniline: the crystal structure of 1-phenylimino-2-phenylamino-3-phenylindene

1987 ◽  
Vol 65 (12) ◽  
pp. 2830-2833 ◽  
Author(s):  
David M. McKinnon ◽  
Peter D. Clark ◽  
Robert O. Martin ◽  
Louis T. J. Delbaere ◽  
J. Wilson Quail
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Direct Methods ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

3,5-Diphenyl-1,2-dithiolium-4-olate (1) reacts with aniline to form 1-phenylimino-2-phenylamino-3-phenylindene (3a). Under suitable conditions, 6-phenylbenzo[b]indeno[1,2-e]-1,2-thiazine is also formed. These structures are confirmed by alternative syntheses. The molecular structure of 3a has been determined by single crystal X-ray diffraction. Compound 3a crystallizes in the monoclinic space group C2/c with unit cell dimensions a = 20.777(3) Å, b = 6.130(3) Å, c = 31.327(3) Å, 3 = 99.59(1)°, and Z = 8. The structure was solved by direct methods and refined by least squares to a final R = 0.055. The molecular structure of 3a shows the three phenyl containing substituents to have the planes of their ring systems tilted between 40° and 60° from the plane of the indene system due to steric repulsions.

An X-ray structural examination of an intermediate from the cleavage of a vic-diol by iodine(I) acetate

1980 ◽  
Vol 33 (3) ◽  
pp. 671 ◽  
Author(s):  
PG Beckingsale ◽  
JM Waters ◽  
TN Waters
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Direct Methods ◽  
Structural Examination ◽  
Space Group ◽  
X Ray

The crystal structure of a compound isolated after reaction of iodine(1) acetate with cis-cyclohexane-1,2-diol has been determined by direct methods. It is identified as 2,2'-(butane-1,4-diyl)bis(hexahydro-1,3-benzodioxole). Crystals are orthorhombic, a 8.625(2), b 7.589(1), c 26.187(5) Ǻ, space group Pbca, Z 4. Least- squares refinement brought R to 0.046.

The methylgallium-2-carboxylatobenzimidazolato hexamer, [MeGa·C8H4N2O2]6·C6H6·(Me2C6H4)2; synthesis and X-ray crystal structure

1999 ◽  
Vol 77 (4) ◽  
pp. 434-438 ◽  
Author(s):  
Steven J Rettig ◽  
Alan Storr ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Carboxylic Acid ◽  
Room Temperature ◽  
Direct Methods ◽  
Membered Ring ◽  
Coordination Geometry ◽  
Temperature Reaction ◽  
Full Matrix ◽  
X Ray ◽  
Solvent Molecules

The room-temperature reaction of Me3Ga with benzimidazole 2-carboxylic acid in xylene solvent has yielded a novel crystalline hexameric gallium compound with "MeGa" moieties bridged by the doubly depronotated ligand precursor. Crystals of [MeGa(4,5-benzimidazolato-2-carboxylato)]6·(C6H6)·(m-Me2C6H4)2 are monoclinic, a = 18.091(2), b = 17.094(2), c = 13.2215(5) Å, Z = 2, space group C2/m. The structure was solved by direct methods and refined by full-matrix least-squares procedures to R (F, I [Formula: see text] 3σ(I)) = 0.064 (Rw (F2, all data) = 0.134). The hexameric Ga complex contains a six-membered ring of Ga atoms, bridged by the benzimidazolate ligands with the benzo rings projecting alternately above and below the Ga plane, thus forming a ball-shaped molecule. The complex could have ideal D3d symmetry, but it contains an encapsulated molecule of benzene, which distorts the regularity of the Ga6 hexagon, and reduces the symmetry of the complex to the crystallographically observed C2h. The coordination geometry at each of the two independent GaO2N2C centres approximates a trigonal bipyramid, with a N2C trigonal plane, and the O atoms above and below; average dimensions are Ga-O = 2.176(2), Ga-N = 1.973(3), Ga-C = 1.927(5) Å, O-Ga-O = 165°. The unit cell also contains four m-xylene solvent molecules (outside the molecular cage).Key words: gallium, crystal structure, benzene intercalate, benzimidazolecarboxylic acid.

Crystal structure of zerumbone [(E,E,E)-2,6,9,9-Tetramethylcycloundeca-2,6,10-trien-1-one]

1981 ◽  
Vol 34 (10) ◽  
pp. 2243 ◽  
Author(s):  
SR Hall ◽  
S Nimgirawath ◽  
CL Raston ◽  
A Sittatrakul ◽  
S Thadaniti ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Membered Ring ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Zingiber Zerumbet ◽  
Space Group ◽  
X Ray ◽  
Considerable Distortion

The crystal structure of zerumbone, C15H22O, extracted from the rhizomes of Zingiber zerumbet Smith, has been determined by single-crystal X-ray diffraction at 295(1) K and refined by least squares to a residual of 0.051 for 925 'observed' reflections. Crystals are monoclinic, space group P21/c, a 9.036(3), b 9.712(5), c 15.643(6) �, β 97.19(3)�, Z = 4. Although the molecule has no chiral centre, the presence of the three trans double bonds confers considerable distortion and rigidity on the eleven-membered ring and renders the whole molecule chiral and potentially resolvable.

Crystal structure of 17,18,19-trisnorstemodan-3,13-dione

1984 ◽  
Vol 62 (9) ◽  
pp. 1828-1830 ◽  
Author(s):  
Stephen V. Evans ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Title Compound ◽  
Direct Methods ◽  
Membered Ring ◽  
Full Matrix ◽  
Bond Lengths ◽  
Compound C ◽  
Tetracyclic System ◽  
Atom Bond

Crystals of the title compound, C17H24O2, are monoclinic, P21/c, a = 10.395(2), b = 10.980(1), c = 13.181(3) Å, β = 113.55(1)°, Z = 4. The structure was solved by direct methods and refined by full-matrix least-squares to R = 0.051 for 1622 reflections with I ≥ 3σ(I). The molecule contains a tetracyclic system of three six-membered rings and one five-membered ring; the structure exhibits disorder of one C atom. Bond lengths and angles are normal.

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