The Crystal and Molecular Structure of 3-Chloro-3-deoxy-1,2;5,6-di-O-isopropylidene-β-D-idose

1972 ◽  
Vol 50 (1) ◽  
pp. 93-98 ◽  
Author(s):  
F. W. B. Einstein ◽  
K. N. Slessor

The crystal and molecular structure of 3-chloro-3-deoxy-1,2;5,6-di-O-isopropylidene-β-D-idose has been determined from three dimensional X-ray data collected by counter methods. The structure was refined by full-matrix least-squares techniques to a conventional R factor of 5.7% for the 817 observed reflections. The compound crystallizes in the orthorhombic space group P212121 with four molecules in a cell of dimensions a = 9.744(6), b = 26.76(2), c = 5.403(3) Å.The structure analysis has served to confirm the site of halogenation and that it occurs stereospecifically. The conformation of the furan ring is an envelope arrangement with C(4) displaced from the mean plane.

1978 ◽  
Vol 56 (12) ◽  
pp. 1602-1609 ◽  
Author(s):  
Robert F. Stepaniak ◽  
Nicholas C. Payne

The crystal and molecular structure of trans-chloro(3-hydroxypropyl-N,N-dimethylaminocarbene)bis(dimethylphenylphosphine)platinum(II) hexafluorophosphate has been determined from three-dimensional X-ray data collected on an automated four circle diffractometer using CuKα radiation. The compound crystallizes in the orthorhombic space group Pna21, with Z = 4, and cell dimensions a = 14.403(2), b = 12.631(2), and c = 16.151(2) Å. Full matrix least-squares refinement on F gave a final conventional R factor of 0.047 for 3442 observations with I > 3σ(I). The cation coordination geometry is square planar, with the carbene ligand lying approximately perpendicular to the plane. The Pt—Cl bond length is 2.356(4) Å and the Pt—C(carbene) distance is 1.978(12) Å. The C(carbene)—N bond length is 1.293(16) Å. These dimensions are discussed in terms of the trans influences of the carbene and chloride ligands and the bonding in the carbene species.


1974 ◽  
Vol 52 (22) ◽  
pp. 3793-3798 ◽  
Author(s):  
J. G. Contreras ◽  
F. W. B. Einstein ◽  
D. G. Tuck

The molecular structure of dicholoro(acetylacetonato)-2,2′-bipyridylindium(III) has been determined from three dimensional X-ray data collected by counter methods. The structure has been refined by least-squares techniques to a conventional R factor of 4.3% for the 3524 observed reflections. Crystals of Cl2In(acac)(bipy) are monoclinic, a = 11.340(3), b = 12.198(3), c = 14.330(3) Å, β = 120.25(2)°, z = 4, space group P21/c. The chloride ligands are cis, with In—Cl at distances of 2.443(1) and 2.394(1) Å; the In—O bond lengths are 2.124(3) and 2.164(3) Å, and the In—N bond distances are 2.276(4) and 2.299(4) Å.


1971 ◽  
Vol 49 (3) ◽  
pp. 468-476 ◽  
Author(s):  
Lilian Y. Y. Chan ◽  
F. W. B. Einstein

The crystal structure of potassium hydrogen di-iodate (bi-iodate) KIO3.HIO3 was determined from three dimensional X-ray data collected by counter methods. The structure was refined by full-matrix least-squares techniques to a conventional R factor of 5.0 % for the 1392 observed reflexions. The salt crystallizes in the monoclinic space group P21/c with eight formula units in a cell of dimension a = 7.028(1) Å, b = 8.203(1) Å, c = 21.841(3) Å, β = 98.03(1)°.The iodate units are all basically pyramidal; weak interionic I—O contacts complete a very distorted octahedral environment around three iodine atoms. There is a capped octahedral (7-coordinate) environment around the remaining iodine atom. The I—O bonds are in the range 1.75–1.82 Å and the I—OH bonds are 1.91 and 1.95 Å, variations in length can be correlated with differences in the degree of involvement in (a) hydrogen bonding and (b) interaction with adjacent iodine atoms.


1972 ◽  
Vol 25 (10) ◽  
pp. 2117 ◽  
Author(s):  
MD Brice ◽  
BR Penfold ◽  
WT Robinson

The crystal and molecular structure of 4α-t-butylcyclohexane-1β,2,β-diol, C10H20O2, has been determined by X-ray diffraction methods. The compound crystallizes in the triclinic space group Pi with 4 molecules in a unit cell of dimensions a = 12.268, b = 15.921, c = 6.322�, α = 82.53, β = 114.45, γ = 111.13�. The intensity data were measured by counter methods using Cu Kα radiation; the structure was solved by means of the tangent formula, and was refined using full matrix least-squares techniques to a final R-factor of 0.063 for 1199 reflections. The crystal structure consists of two sets of crystallographically non-equivalent molecules hydrogen-bonded to form discrete chains parallel to the c axis. The cyclohexane rings are in the chair conformation.


1982 ◽  
Vol 60 (16) ◽  
pp. 2075-2081 ◽  
Author(s):  
Peter H. Bird ◽  
Upali Siriwardane ◽  
Rabin D. Lai ◽  
Alan Shaver

Fusion invacuo of complexes of the type P2Pt(SR)2 is a facile route to dimers of the type [PPt(SR)(μ-SR)]2; thus, the compounds cis-P2Pt(SR)2, where P = PPh3, PMePh2, R = CH2Ph and trans-P2Pt(SR)2, where P = PPh3, PMePh2, PMe2Ph, R = 4-C6H4CH3 gave the appropriate dimers 1–5. A three-dimensional X-ray structure analysis of the complex [(PMePh2)Pt(SCH2Ph)(μ-SCH2Ph)]2, 2, has shown that it has cis geometry with the benzyl groups of the bridging thiolato ligands oriented anti with respect to each other. The dihedral angle between the two square planes is 138.8°. Crystals of 2 are triclinic, space group [Formula: see text], with two molecules in a cell of dimensions a = 10.856(3) Å, b = 19.935(5) Å, c = 12.202(4) Å, α = 82.52(2)°, β = 105.18(2)°, and γ = 92.35(2)°. Full-matrix least-squares refinement converged at R = 0.052.


1983 ◽  
Vol 36 (6) ◽  
pp. 1249 ◽  
Author(s):  
TW Hambley ◽  
MR Snow

An X-ray crystallographic analysis of zinc(II) monoglycerolate has been carried out. The crystals are monoclinic, space group P21/c with a 8.110(1), b 6.404(1), c 8.714(2)� β 93.44(1)�. The structure was refined by full-matrix least-squares techniques to an R factor (on 519F) of 0.019. The analysis reveals that the zinc atoms bridge the glycerolate molecules forming polymeric sheets lying parallel to the bc plane. Only aliphatic hydrogens are disposed into the space between the layers, a fact consistent with the lubricity and hydrophobic nature of the solid complex and the observed facile lamellar cleavage perpendicular to the a axis.


1979 ◽  
Vol 57 (11) ◽  
pp. 1368-1371 ◽  
Author(s):  
Richard G. Ball ◽  
James Trotter

The molecular structure of cis-dichloro(2,2′-o-phenylenebisbenzothiazole)copper(II) has been determined by single crystal X-ray diffractometry. The crystal is monoclinic, P21/n, a = 8.408(1), b = 15.819(1), c = 14.229(2) Å, β = 93.19(1)°, and Z = 4. The structure has been refined by full-matrix least-squares techniques on F, using 3316 unique reflections for which F2 > 3σ(F2), to a final agreement factor of 0.028. The complex adopts an approximately square planar coordination geometry with the Cu bound to two cis Cl atoms and the N atoms of the chelating benzothiazole ligand. The mean Cu—N and Cu—Cl distances are 2.016(6) and 2.217(6) Å, respectively.


1980 ◽  
Vol 33 (6) ◽  
pp. 1373 ◽  
Author(s):  
GB Robertson ◽  
PO Whimp

The crystal and molecular structure of a platinum(0) complex of cyclooctyne, [(coct)Pt(PPh3)2], has been determined from three- dimensional X-ray data collected by counter methods. The complex crystallizes in the space group P21/n [a non-standard setting of space group P21/c (C2h5, No. 14)], with a 20.660(9), b 12.299(5), c 15.470(7) Ǻ, β 110.26(2)°, Z 4. The structure was solved by conventional Patterson and Fourier methods and was refined by block-diagonal least-squares techniques to weighted and unweighted R-factors of 0.048 and 0.047 respectively, for the 4733 unique reflections with I/σ(I) ≥ 3.0. The molecule is essentially square planar about the 'central' platinum atom, with the triphenylphosphine groups occupying cis coordination sites. The Pt-C distances are equal within experimental error [2.034(9) and 2.037(9) Ǻ] and compare favourably with the corresponding distances in the platinum(0)-cyclohexyne and -cycloheptyne analogues. The acetylenic C=C distance is 1.279(13) Ǻ and shows the normal bond lengthening consequent upon coordination.


1972 ◽  
Vol 50 (9) ◽  
pp. 1315-1320 ◽  
Author(s):  
J. Brian Faught

The crystal structure of tetrameric phosphonitrilic isothiocyanate, N4P4(NCS)8, has been determined by three-dimensional X-ray studies from data collected on a Picker FACS-1 automated diffractometer. The compound crystallizes in the triclinic space group [Formula: see text] with a = 8.098(8), b = 8.018(7), c = 9.937(10) Å, α = 104.08(7), β = 99.42(7), γ = 95.42(7)°, and one molecule per unit cell. The structure was solved from 1766 independent non-zero reflections and refined to a conventional R factor of 0.063. Nitrogen atoms of two isothiocyanate groups are bonded to each phosphorus atom of the eight-membered phosphorus–nitrogen ring. The ring has a chair configuration. The average dimensions of the structure are P—Nring = 1.543 + 0.017, P—Nisothiocyanate = 1.644 ± 0.011, N—C = 1.168 ± 0.008, C—S = 1.535 + 0.009 Å, [Formula: see text] [Formula: see text] [Formula: see text] [Formula: see text] and NĈS = 176.6 ± 1.1°.


1979 ◽  
Vol 34 (1) ◽  
pp. 48-51 ◽  
Author(s):  
Jürgen Kopf ◽  
Klaus von Deuten ◽  
Bahman Nakhdjavan ◽  
Günter Klar

Abstract The structure of 2,8-dimethyldibenzo[c,g][1,2,5,6]tetrathiaocin (1b) has been determined by X-ray methods and discussed in connection with the preferred conformations of diaryl disulfides. The compound has the anti-form I. The SS-distance is 205.8 pm, the mean CSS-angle 104.1°, and the CSS/SSC-dihedral angle 111.1°.


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