The Crystal Structure of cis-Inositol Monohydrate—Un Objet Retrouvé

1996 ◽  
Vol 49 (3) ◽  
pp. 413 ◽  
Author(s):  
HC Freeman ◽  
DA Langs ◽  
CE Nockolds ◽  
YL Oh
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Direct Methods ◽  
Monoclinic Space Group ◽  
High Symmetry ◽  
Asymmetric Unit ◽  
Fourier Methods ◽  
Full Matrix ◽  
Structure Factors ◽  
Independent Molecules

cis-Inositol monohydrate, C6H12O6.H2O, crystallizes in the monoclinic space group P 21/n [a 9.900(8), b 9.296(8), c 17.795(15) Ǻ, β 90.5(1)°, Z 8]. The normalized structure factors Eh have an atypical statistical distribution, and attempts to solve the structure by direct methods (triplet relationships) were unsuccessful. The structure was ultimately solved by Patterson and Fourier methods, and was refined by full-matrix least squares [Rw = 0.047 for 1665 independent reflections ≥2σ(Imin)]. The cis-inositol molecules have approximately trigonal symmetry, as expected. The difficulties encountered during the structure analysis are explained by the presence of two nearly identical molecules of high symmetry in the asymmetric unit. The independent molecules are related by translational pseudosymmetry, and their orientations are such that all the C-C and C-O bonds in the structure are approximately parallel to a small number of directions.

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.

Crystal structure of the spirophosphorane (OCMe2C(O)O)2PH

1998 ◽  
Vol 76 (7) ◽  
pp. 1060-1063 ◽  
Author(s):  
Craig D Montgomery ◽  
Steven J Rettig ◽  
Bryn Shurmer
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Direct Methods ◽  
Trigonal Bipyramid ◽  
Full Matrix ◽  
Space Group ◽  
Trigonal Bipyramidal Geometry ◽  
Trigonal Bipyramidal ◽  
Independent Molecules ◽  
Distorted Trigonal Bipyramidal

The crystal structure of the spirobicyclic phosphorane (OCMe2C(O)O)2PH, 1, has been determined. Crystals of C8H13O6P, 1, are orthorhombic, a = 10.515(2), b = 10.623(2), c = 20.552(2) Å, Z = 8, space group Pca21. The structure was solved by direct methods and refined by full-matrix least-squares procedures to R = 0.037 (Rw = 0.033) for 1616 reflections with I > 3sigma(I). The structure consists of two independent molecules each displaying a distorted trigonal bipyramidal geometry; the distortion follows closely the Berry pseudorotation coordinate.Key words: crystal structure, phosphorane, Berry pseudorotation, trigonal bipyramid.

Structural studies of organoboron compounds. XLI. (3-Hydroxy-2-methyl-1-(p-tolyl)-4-pyridinonato)diphenylboron

1990 ◽  
Vol 68 (10) ◽  
pp. 1803-1807 ◽  
Author(s):  
Chris Orvig ◽  
Steven J. Rettig ◽  
James Trotter ◽  
Zaihui Zhang
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Direct Methods ◽  
Organoboron Compound ◽  
High Yield ◽  
Structural Studies ◽  
Full Matrix ◽  
Bond Lengths ◽  
The Mean ◽  
Independent Molecules

(3-Hydroxy-2-methyl-1-(p-tolyl)-4-pyridinonato)diphenylboron has been prepared in high yield by the reaction of 3-hydroxy-2-methyl-1-(p-tolyl)-4-pyridinone with diphenylborinic acid. Crystals of the hemi-acetone solvate are triclinic, a = 15.119(2), b = 16.528(1), c = 9.5802(9) Å, α = 98.721(6), β = 93.344(8), γ = 102.443(6)°, Z = 4, space group [Formula: see text]. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.050 and Rw = 0.065 for 4330 reflections with I ≥ 3σ(I). The five-membered chelate rings in both of the two crystallographically independent molecules have flattened B-envelope conformations (maximum deviations from the mean planes = 0.114(4) and 0.065(5) Å). Mean bond lengths O—B = 1.553 and C—B = 1.599 Å are consistent with intermediate strength binding of the diphenylboron moiety by the O,O-chelating ligand. Keywords: crystal structure, organoboron compound.

Studies in aryltin chemistry. Part 6. Crystal and molecular structures of tetra(p-methylsulphonylphenyl)tin(IV) and tetra(p-methylsulphinylphenyl)tin(IV) monohydrate

1990 ◽  
Vol 68 (8) ◽  
pp. 1277-1282 ◽  
Author(s):  
Ivor Wharf ◽  
Michel G. Simard ◽  
Henry Lamparski
Keyword(s):  
Least Squares ◽  
Crystal Structures ◽  
Direct Method ◽  
Molecular Structures ◽  
Water Molecules ◽  
Monoclinic Space Group ◽  
Molecular Symmetry ◽  
Asymmetric Unit ◽  
Full Matrix ◽  
Space Group

Tetrakis(p-methylsulphonylphenyl)tin(IV) and tetrakis(p-methylsulphinylphenyl)tin(IV) n-hydrate have been prepared and their spectra (ir 1350–400 cm−1; nmr, 1H, 13C, 119Sn) and X-ray crystal structures are reported. The first compound is monoclinic, space group C2/c, Z = 4, with a = 21.589(6), b = 6.207(3), c = 22.861(11) Å, β = 93.80(3)° (22 °C); the structure was solved by the direct method and refined by full-matrix least squares calculations to R = 0.043 for 2755 observed reflections. It has 2 molecular symmetry with the methyl group and one oxygen atom completely disordered in both CH3S(O2) groups in the asymmetric unit. The second compound is tetragonal, space group P42/n, Z = 2, with a = b = 15.408(6), c = 6.379(2) Å (−100 °C); the structure was solved by the Patterson method and refined by full-matrix least squares calculations to R = 0.060 for 1209 observed reflections. It has [Formula: see text] molecular symmetry with the whole asymmetric unit disordered. Water molecules occupy positions on parallel 42 axes but molecular packing requirements prevent all sites having 100% occupancy giving n ~ 1 for the hydrate. Keywords: Tetra-aryltins, crystal structures, sulphone, sulphoxide, hydrogen-bonding.

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 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

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.

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.

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.

The Crystal Structure of Dimedone

1975 ◽  
Vol 53 (7) ◽  
pp. 1046-1050 ◽  
Author(s):  
Ishwar Singh ◽  
Crispin Calvo
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Hydrogen Bonds ◽  
Least Squares ◽  
Direct Methods ◽  
Monoclinic Symmetry ◽  
Enolic Form ◽  
Full Matrix ◽  
Space Group ◽  
Least Squares Techniques

Dimedone, C8H12O2, crystallizes with monoclinic symmetry, a = 10.079(7), b = 6.835(3), c = 12.438(4) Å, β = 110.24(5)°, space group P21/n and Z = 4. The structure of this compound was solved by direct methods and refined by full-matrix least-squares techniques using 1205 unique reflections to a final R of 0.047. In the solid state it exists in the enolic form and these molecules pack in the crystal in systems of infinite chains linked together by hydrogen bonds in the y direction. These results are virtually the same as recently reported by Semmingsen.

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