Potential Anticancer Agents, XI. X-Ray Structure Determination of Acantholide [1]

1979 ◽  
Vol 34 (9-10) ◽  
pp. 677-682 ◽  
Author(s):  
H. Lotter ◽  
H. Wagner ◽  
A. A. Saleh ◽  
G. A. Cordell ◽  
N. R. Famsworth
Keyword(s):  
Solid State ◽  
Antitumor Activity ◽  
Sesquiterpene Lactone ◽  
Anticancer Agents ◽  
Structure Determination ◽  
Direct Methods ◽  
X Ray ◽  
Activity Evaluation ◽  
Nmr Data

Abstract The X-ray structure of acantholide, a melampolide sesquiterpene lactone from Acanthosper­mum glabratum (D C .) Willd. was determined by the aid of direct methods. The compound was cy­totoxic but displayed no antitumor activity. Evaluation of the X-ray and NMR data indicated that the same conformation exists in the solid state as in solution.

Structure Determination of 3,5-Biscyclohexylidene-1,2,4-trithiolane / Structure Determination of 3,5-Biscyclohexylidene-1,2,4-trithiolane

1980 ◽  
Vol 35 (8) ◽  
pp. 1015-1018 ◽  
Author(s):  
Werner Winter ◽  
Hanspeter Bühl ◽  
Herbert Meier
Keyword(s):  
General Formula ◽  
Structure Determination ◽  
Title Compound ◽  
Direct Methods ◽  
Spectroscopic Techniques ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Final Structure

Abstract Fragmentation of 1,2,3-thiadiazoles (1) leads to the compounds 5 - 8 with an increasing proportion of sulphur. Numerous structural possibilities exist for the products 7 with the general formula (R2C2)2S3. The number of proposals can be reduced by spectroscopic techniques, but the final structure determination is accomplished by an X-ray analysis of the title compound 7a. 7a crystallizes in the space group P21/c (Z = 4) with cell parameters of a = 9.714(1), b = 16.188(8), c = 9.149(2) Å and β = 98.93(1)°. The structure is solved by direct methods and refined to R = 0.053 with 1955 diffractometer data (I ≥ 2σ(I)). The trithiolane ring has a puckered conformation and the whole molecule shows nearly perfect C2-symmetry, which is not required crystallographically.

Structural Properties of a Dimeric Phenylcyanamidocopper(I) Complex, [{Cu(PPh3)2(C6H5NCN)}2]

2000 ◽  
Vol 53 (12) ◽  
pp. 971 ◽  
Author(s):  
Eric W. Ainscough ◽  
Andrew M. Brodie ◽  
Peter C. Healy ◽  
Joyce M. Waters
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Structural Properties ◽  
Structure Determination ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Cross Polarization ◽  
X Ray ◽  
Angle Spinning

The X-ray crystal structure determination of bis[-(phenylcyanamido)bis(triphenylphosphine)copper(I)], [{Cu(PPh3)2(C6H5NCN)}2], (1) is reported. The complex has a centrosymmetric dimeric structure with the phenylcyanamide ligands bridging the copper atoms in a -1,3-fashion. The structure is compared with that of the 4-methylphenylcyanamido complex, [{Cu(PPh3)2(4-MeC6H4NCN)}2] (2), and the differences observed in the Cu–P bond lengths compared with changes in the solid state 31P cross-polarization magic-angle spinning (CPMAS) spectra of the two complexes.

NMR Spectroscopy of Tetra(propyn- 1-yl)silane in the Solid State and in Solution

2003 ◽  
Vol 58 (8) ◽  
pp. 809-812 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Oleg L. Tok ◽  
Amin Badshah
Keyword(s):  
Solid State ◽  
Bulk Material ◽  
Point Group ◽  
Coupling Constants ◽  
Data Set ◽  
Tin Compounds ◽  
X Ray ◽  
Nmr Data ◽  
Solid State Structures

The crystal structure of tetra(propyn-1-yl)silane, Si(C≡CMe)4 1, has revealed a completely asymmetric molecule (point group C1). Since this finding concerns a single crystal, the bulk material of 1 was studied by solid-state 29Si and 13C MAS NMR. This confirmed the result of the X-ray analysis, and by comparison with previous NMR measurements of the tin analogue 1(Sn) it is concluded that 1 and 1(Sn) must have very similar solid-state structures which are in contrast to those known for other tetra(alkyn-1-yl)silicon and -tin compounds. The NMR data set of 1 in solution was completed by determination of the magnitude of coupling constants 1J(13C,13C).

scholarly journals Exploiting the Synergy of Powder X-ray Diffraction and Solid-State NMR Spectroscopy in Structure Determination of Organic Molecular Solids

2013 ◽  
Vol 117 (23) ◽  
pp. 12258-12265 ◽  
Author(s):  
Dmytro V. Dudenko ◽  
P. Andrew Williams ◽  
Colan E. Hughes ◽  
Oleg N. Antzutkin ◽  
Sitaram P. Velaga ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Structure Determination ◽  
Solid State Nmr ◽  
Molecular Solids ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solid State Nmr Spectroscopy

scholarly journals Metallation of Isatin (2,3-Indolinedione). X-Ray Structure and Solution Behavior of Bis(Isatinato)Mercury(II)

1995 ◽  
Vol 2 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Angel Garcia-Raso ◽  
Juan J. Fiol ◽  
Elies Molins ◽  
Antonia M. Calafat ◽  
Patricia A. Marzilli ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Metal Complex ◽  
Bond Length ◽  
Spectral Data ◽  
Structure Determination ◽  
Monoclinic System ◽  
Heterocyclic Nitrogen ◽  
X Ray

The first X-ray structure of an isatin (2,3-indolinedione, isaH) metal complex, bis(isatinato)memury(II) (C16H8N2O4Hg) (1), was determined. (1) was obtained from the reaction of isaH with mercury(II) acetate in methanol. Analogously, treatment of sodium saccharinate and mercury(II) acetate in methanol yielded Hg(saccharinato)2•0.5CH3OH (3). (1) crystallizes in the monoclinic system, space group P21/a with a = 7.299(1) Å, b = 8.192(1) Å, c = 11.601(1) Å , β = 105.82(1)°, V = 667.4 Å3, Z = 2, Dcalc = 2.452 g cm−3, MoKα radiation(λ = 0.71073 Å), μ = 115.5 cm-1, F(000) = 460, 21(1) °C. The structure was refined on the basis of 2023 observed reflections to R= 0.044. The two deprotonated, non coplanar isa ligands are trans to each other in a head to tail orientation and bound to the Hg through the nitrogen in a linear N-Hg-N arrangement. The Hg atom is at the center of symmetry of the complex and displaced by 0.62 Å from the two planes of the isa ligands (τ Hg-N1-C2-O2= -16°). The Hg-N bond length is 2.015 Å. Noπ-aryl-memury(ll)-π-aryl stacking interaction was observed either in the solid state or in the solution state. The IR, electronic, and H1 and C13NMR spectral data of (1) and (3) suggest binding of the memury to the heterocyclic nitrogen, in agreement with the crystal structure determination of (1).

Reaktion von 1.4-Dienen mit Metallkomplexen, I Darstellung und Röntgenstrukturanalyse eines π-enyl-Komplexes der Zusammensetzung (C8H13PdCl)2/ Reaction of 1,4-Dienes with Metal Complexes, I Synthesis and X-ray Structure Determination of a π-enyl Complex of Composition (C8H18PdCl)2

1976 ◽  
Vol 31 (4) ◽  
pp. 455-462 ◽  
Author(s):  
Peter Feldhaus ◽  
Richard Ratka ◽  
Hermann Schmid ◽  
Manfred L. Ziegler
Keyword(s):  
Metal Complexes ◽  
Structure Determination ◽  
Three Dimensional ◽  
Fourier Methods ◽  
X Ray ◽  
H Nmr ◽  
Nmr Data ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

Reaction of (C6H5CN)2PdCl2 and 1,3-dimethylenecyclohexane led to an exocyclic π-enyl complex of formula (C8H13PdCl)2-bis(η3-2-methylene-6-methylcyclohexyl)(di-µ-chloro)-dipalladium. IR and 1H NMR data are in agreement with this formulation.The compound is monoclinic, with unit cell dimensions α = 499.97 ± 0.08, b =1342.26 ± 0.19, c =1379.60 ± 0.20 pm, β = 99.43 ± 0.02°, space group C5h2-P21/C, Ζ = 2, dX-ray = 1.83 g/cm3.The structure was determined from three-dimensional X-ray data by Patterson and Fourier methods. Least squares refinement by use of 1045 independent reflections has reached R1 = 5.6%.

Desangeloylshairidin, X-ray structure determination of a sesquiterpene lactone from Guillonea scabra

1983 ◽  
Vol 22 (9) ◽  
pp. 1983-1984 ◽  
Author(s):  
J FAYOS ◽  
A PERALES ◽  
M PINAR ◽  
M RICO ◽  
B RODRIGUEZ
Keyword(s):  
Sesquiterpene Lactone ◽  
Structure Determination ◽  
X Ray

scholarly journals Structure Determination of Molecular Solids from Powder X-ray Diffraction Data

2014 ◽  
Vol 70 (a1) ◽  
pp. C1557-C1557
Author(s):  
Kenneth Harris
Keyword(s):  
Solid State ◽  
Structure Determination ◽  
Solid State Nmr ◽  
Structural Information ◽  
Powder Xrd ◽  
Computational Techniques ◽  
Molecular Solids ◽  
X Ray Diffraction ◽  
X Ray

Structure determination of organic molecular solids from powder X-ray diffraction (XRD) data [1] is nowadays carried out extensively by researchers in both academia and industry, and the development of new methodology in this field has made particularly significant impact in the pharmaceuticals industry within the last 20 years or so. However, although software for carrying out each stage of the procedure for structure determination from powder XRD data is now readily accessible and relatively straightforward to use, it is essential that the results from such structure determination calculations are subjected to careful scrutiny to confirm that the final structure obtained is actually correct. In this regard, it can be particularly advantageous to augment the analysis of the powder XRD data and to assist the scrutiny of the structural results by considering complementary structural information derived from other experimental and computational techniques. Techniques that can be particularly valuable in this regard include solid-state NMR spectroscopy, energy calculations (either on individual molecules or periodic crystal structures), vibrational spectroscopies, and techniques of thermal analysis (e.g. DSC and TGA). The lecture will give an overview of the current "state of the art" in the structure determination of organic materials from powder XRD data, giving emphasis [2,3] to the opportunities to enhance the structure determination process by making use of information derived from other experimental (especially solid-state NMR) and computational techniques. Recent results will be presented, with emphasis on raising issues of relevance to research on pharmaceutical materials.

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