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.

Ring contraction of 4-substituted 2,6-dichlorophenols. The crystal structure of 2,2,4α,5α-Tetrachloro-1α,3α-dihydroxycyclopentane-1,4-carbolactone

1977 ◽  
Vol 30 (10) ◽  
pp. 2195 ◽  
Author(s):  
RM Christie ◽  
RW Rickards ◽  
KJ Schmalzl ◽  
D Taylor
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Direct Methods ◽  
Major Product ◽  
X Ray Diffraction ◽  
Ring Contraction ◽  
Full Matrix ◽  
Space Group ◽  
X Ray ◽  
Counter Data

Alkaline chlorination of the 4-alkyl-2,6-dichlorophenols (2b) and (2c) proceeds through ring contraction and halolactonization to form the 4α- alkyl-2,2,5α-trichloro-1α,3α-dihydroxycyclopentane-1,4-carbolactones (4b) and (4c). Under similar conditions, 2,4,6-trichlorophenol affords the analogous 2,2,4α,5α-tetrachloro-1α,3α-dihydroxycyclopentane-1,4- carbolactone (4a) in low yield, in addition to the Hantzsch acid (3a) as the major product. The acid (3a) upon further treatment undergoes chloro-lactonization to give the lactone (4a). The structures of the lactones (4b) and (4c) follow from spectroscopic comparison with (4a), the structure of which has been established by X-ray diffraction (C6H4Cl4O4 orthorhombic a 13.485(1), b 12.348(1), c 11.371(1) Ǻ, space group Pccn, Z 8, solved by direct methods and refined by block-diagonal and full-matrix least squares to R 0.031, Rw 0.043 for 1313 unique counter data with I/σ(I) ≥ 3.0).

Preparation and X-ray crystal structure of (4bα,6β,9β,9aα,10α,13α)-4b,5,6,7,8,9,9a,10,11,12,13,14-dodecahydro-4b-phenyl-6,9:10,13-dimethanodicyclohepta[a,c]naphthalene

1980 ◽  
Vol 58 (17) ◽  
pp. 1847-1850 ◽  
Author(s):  
Alan Richard Harris ◽  
Keith Mills ◽  
Michael Martin-Smith ◽  
Peter Murray-Rust ◽  
Judith Murray-Rust
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
The Novel ◽  
Oxidative Dimerization ◽  
Full Matrix ◽  
X Ray ◽  
X Ray Crystallography

The novel hexacyclic title hydrocarbon, formed by an unusual oxidative dimerization of 3-phenylbicyclo[3,2,1]oct-2-ene, has been isolated and its structure elucidated by means of X-ray crystallography. The trivial name 4b-phenylmariontetraene is proposed for the hydrocarbon. Crystals are orthorhombic, Pbca; a = 21.87(2), b = 10.57(2), c = 17.41(2) Å from diffractometer measurements (Mo [Formula: see text] radiation). V = 4024.2 Å3, Z = 8, Dc = 1.21 Mg m−3, F(000) = 1584, μ = 0.34 cm−3. The structure was solved by direct phasing methods with MULTAN 78 and was refined by weighted full-matrix least-squares procedures to R = 0.046 for 2287 observed reflexions.

Crystal structure of Bis(O-ethylxanthato)-1,10-phenanthrolinecadmium(II)

1976 ◽  
Vol 29 (4) ◽  
pp. 739 ◽  
Author(s):  
CL Raston ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Title Compound ◽  
Crystallographic Axis ◽  
Full Matrix ◽  
X Ray ◽  
X Ray Crystallography ◽  
Phenanthroline Ligand

The crystal structure of the title compound, [Cd(C12H8N2)(CS2OEt)2], has been determined by X-ray crystallography using diffractometer data at 295 K and refined by full matrix least squares to a residual of 0.06 for 1350 'observed' reflections. Crystals are orthorhombic, P bcn, a = 14.870(4), b = 14.549(8), c = 10.249(1) �, Z = 4. The molecule lies on a twofold crystallographic axis; the phenanthroline ligand is symmetrically bidentate [Cd-N, 2.386(8) �], while the ethylxanthateligand is somewhat asymmetric [Cd-S, 2.647(3), 2.727(3)4 with a correspondingly asymmetric C-S geometry [C-S, 1.72(1), 1.66(1) �].

The crystal structure and stereochemistry of 2-acetyl-3,5,6-trihydroxy-5,6-dimethyl-2-cyclohexenones

1988 ◽  
Vol 66 (2) ◽  
pp. 246-248 ◽  
Author(s):  
Giorgio Adembri ◽  
Mirella Scotton ◽  
Alessandro Sega
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Structure Analysis ◽  
Direct Methods ◽  
Crystal Structure Analysis ◽  
Full Matrix ◽  
Space Group ◽  
X Ray ◽  
Bicyclic System ◽  
Centrosymmetric Dimers

The stereochemistry of 3a, one of the 2-acetyl-3,5,6-trihydroxy-5,6-dimethylcyclohexenones, obtained by rearrangement of 2,3-diacetyl-4-hydroxy-4-methylcyclopentenone, 2a, under basic conditions, was determined by an X-ray crystal structure analysis. An ORTEP plot shows the configuration of (5RS,6RS)-2-acetyl-3,5,6-trihydroxy-5,6-dimethylcyclohexenone and the presence of a conjugated chelated system involving the H-bonding between O(3)… H(31) and H(31)… O(2).Crystals of 3a are triclinic, a = 10.979(4), b = 7.766(3), c = 6.382(3) Å, α = 86.23(2), β = 72.86(1), γ = 88.23(2)°, Z = 2, space group [Formula: see text]. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.036 and Rw = 0.039 for 1324 reflections with I > 3σ(I).The structure of 3a consists of centrosymmetric dimers which contain a nearly planar bicyclic system of a cyclohexenone moiety and a chelated system (Scheme 2).The pathway of the reaction allows one to put forward some hypothesis on the stereochemistry of some analogues of the cyclohexenones 3a and 3b.Faisant appel à la diffraction des rayons-X, on a déterminé la stéréochimie du composé 3a, une des acétyl-2 trihydroxy-3,5,6 diméthyl-5,6 cyclohexénones obtenues par une transposition de la diacétyl-2,3 hydroxy-4 méthyl-4 cyclopenténone, 2a, en milieu alcalin. Une courbe ORTEP démontre que la configuration est (5RS,6RS) pour l'acétyl-2 trihydroxy-3,5,6 diméthyl-5,6 cyclohexénone et qu'il existe un système de chélation conjugué impliquant des liaisons hydrogènes entre O(3)… H(31) et H(31)… O(2).

Porphyrins incorporating heterocyclic N-oxides: (oxidopyridyl)porphyrins, porphyrin-N-oxides, and a tirapazamine-porphyrin conjugate

1999 ◽  
Vol 77 (2) ◽  
pp. 182-198 ◽  
Author(s):  
Jeffrey J Posakony ◽  
Russell C Pratt ◽  
Steven J Rettig ◽  
Brian R James ◽  
Kirsten A Skov
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Key Words ◽  
Direct Methods ◽  
Spectroscopic Methods ◽  
Full Matrix ◽  
Space Group ◽  
X Ray

Porphyrins containing one to four 4-pyridyl groups as meso-substituents were synthesized via a mixed aldehyde condensation, and then "N-oxidized" with m-chloroperbenzoic acid to produce five novel (oxidopyridyl) porphyrins and seven porphyrin-N-oxides, which were characterized by analysis and spectroscopic methods, especially NMR; an X-ray crystal structure of 5-(1-oxido-4-pyridyl)-10,15,20-triphenylporphyrin was also obtained. Crystals of (oxidopyridyl)triphenylporphyrin are tetragonal, a = b = 15.174(1), c = 13.709(1) Å, Z = 4, space group I2d. The structure was solved by direct methods and refined by full-matrix least-squares procedures to R = 0.031 (Rw = 0.026) for 685 reflections with I [Formula: see text] 3σ(I). Sulfonation of two of the (oxidopyridyl)porphyrins was achieved readily with no loss of oxygen from the oxidopyridyl groups. Tirapazamine (3-amino-1,2,4-benzotriazine-1,4-di-N-oxide) was treated with triphosgene to yield the previously reported 2H-[1,2,4]oxadiazolo[3,2-c][1,2,4]benzotriazin-2-one-5-oxide (1); this reacts like an isocyanate and with 5-(4-aminophenyl)-10,15,20-triphenylporphyrin yields a tirapazamine-porphyrin conjugate (2).Key words: porphyrin-N-oxides, (oxidopyridyl)porphyrins, tirapazamine.

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.

The crystal structure of arsenic telluroxide AsTe0.5O2

1993 ◽  
Vol 205 (1) ◽  
Author(s):  
A. C. Stergiou
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Single Crystals ◽  
Direct Methods ◽  
Anomalous Dispersion ◽  
Thermal Parameters ◽  
Trigonal Prism ◽  
Population Parameter ◽  
Full Matrix

AbstractSingle crystals of AsTeSolution of the structure was essentialy effected by direct methods combined with successive Fourier syntheses. The positional and anisotropic thermal parameters were refined by full-matrix least-squares calculations. Absorption and anomalous dispersion corrections were applied to all atoms. The finalThe As atom is coordinated by six O atoms forming a right trigonal prism. The Te atom site is partially occupied by Te atoms with a population parameter 0.5 and surrounded by six O atoms also forming a right trigonal prism. The structure looks like that of NiAs. Each of the AsO

Crystal structure of Tetracyclo[5,3,1,12,6,04,9]dodecane (iceane)

1977 ◽  
Vol 30 (8) ◽  
pp. 1837 ◽  
Author(s):  
DPG Hamon ◽  
CL Raston ◽  
GF Taylor ◽  
JN Varghese ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Rigid Body ◽  
Least Squares ◽  
Title Compound ◽  
Molecular Geometry ◽  
Thermal Motion ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Hexagonal Close Packed

The crystal structure of the title compound, C12H18, has been determined at 295 K by X-ray diffraction and refined by full-matrix least squares to a residual of 0.049 for 216 ?observed? reflections; molecular geometry has been corrected for the effects of thermal motion using a rigid body approximation. Crystals are hexagonal, P63/m, a = 6.582(1), c = 11.843(3) Ǻ, Z = 2, the molecules occupying a hexagonal close- packed array.

Studies Directed Towards the Total Synthesis of Anticapsin. X-Ray Crystal-Structure of (1RS,2SR,4RS,5RS,6SR)-5-Hydroxy-2-phthalimido-1-trimethylsilyloxy-bicyclo[2.2.2]octane-2,6-carbolactone

1990 ◽  
Vol 43 (11) ◽  
pp. 1827 ◽  
Author(s):  
MJ Crossley ◽  
TW Hambley ◽  
AW Stamford
Keyword(s):  
Crystal Structure ◽  
Amino Acid ◽  
Total Synthesis ◽  
Synthetic Approach ◽  
Hydrogen Atoms ◽  
Full Matrix ◽  
X Ray ◽  
X Ray Crystallography ◽  
Relative Stereochemistry ◽  
Atomic Parameters

The relative stereochemistry of methyl 2-phthalimido-1- trimethylsilyloxybicyclo[2.2.2]oct-5-ene-2-carboxylate (9) and its 5,6-epoxide (10), intermediates in a synthetic approach to the amino acid antibiotic anticapsin, were established by the TiCl4-mediated cyclization of (10) to the carbolactone (12); the structure of which was proved by single-crystal X-ray crystallography. Full-matrix least- squares refinement of all atomic parameters with individual isotropic thermal parameters for the hydrogen atoms by using 1446 reflections converged at R 0.036. Crystals of (12) are monoclinic, P21/c, a 12.342(3), b 12.239(2), c 13.405(3) Ǻ, β 99.34(2)°, Z 4.

Structural studies of organoboron compounds. XLIII. 4-[(1-Hydroxycyclohexyl)methyl]-2,2,5-triphenyl-1,3-dioxa-4-azonia-2-borata-4-cyclopentene

1991 ◽  
Vol 69 (3) ◽  
pp. 545-549 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Ute Schumacher ◽  
Mahmood Tajerbashi ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Key Words ◽  
Hydroxamic Acid ◽  
Direct Methods ◽  
Organoboron Compound ◽  
Structural Studies ◽  
Full Matrix ◽  
Bond Lengths ◽  
Acid Chelate

The reaction of N′-hydroxy-N-[(1-hydroxycyclohexyl)methyl]benzamide and diphenylborinic anhydride gives 4-[(1-hydroxycyclohexyl)methyl]-2,2,5-triphenyl-1,3-dioxa-4-azonia-2-borata-4-cyclopentene in nearly quantitative yield. Crystals of the product are monoclinic, a = 9.9117(6), b = 13.308(1), c = 17.339(2) Ǻ, β = 99.420(7)°, Z = 4, space group P21/c. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.040 and Rw = 0.047 for 2423 reflections with I > 3σ(I). The molecule has a normal five-membered hydroxamic acid chelate structure, the BONCO ring having a B-envelope conformation. Bond lengths (corrected for libration) (N)O—B = 1.535(3), (C)O—B = 1.569(3), C—B = 1.603(3) and 1.601(3) Ǻ are normal for this type of complex. Key words: organoboron compound, boron compound, crystal structure.

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