Macrocyclic ligand control of the thermodynamic stabilities of nickel complexes containing 14- to 17-membered macrocyclic rings. X-Ray crystal structure of the trans nickel(II) bromide complex of the 16-membered ring

1979 ◽  
pp. 812 ◽  
Author(s):  
Kenneth R. Adam ◽  
Leonard F. Lindoy ◽  
Roland J. Smith ◽  
Giorgio Anderegg ◽  
Kim Henrick ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Macrocyclic Ligand ◽  
Nickel Complexes ◽  
Membered Ring ◽  
X Ray ◽  
Bromide Complex

Synthesis, crystal structure and molecular conformation of (±)-1-oxoferruginol and (±)-shonanol

2004 ◽  
Vol 219 (10) ◽  
Author(s):  
Swastik Mondal ◽  
Monika Mukherjee ◽  
Arnab Roy ◽  
Debabrata Mukherjee
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Diffraction Data ◽  
Molecular Conformation ◽  
Membered Ring ◽  
Methyl Groups ◽  
Single Bond ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Structures

Abstract(±)-1-oxoferruginol and (±)-shonanol, two potential intermediates in the synthesis of tricyclic diterpenoid ferruginol, have been prepared and crystal structures of the compounds have been investigated using single-crystal X-ray diffraction data. The methyl groups of the isopropyl moiety in (±)-shonanol are disordered over two positions with occupation factors 0.65(1) and 0.35(1), respectively. Although the chemical structures of two compounds are very similar, a C—C single bond in the terminal six-membered ring of (±)-1-oxoferruginol is replaced by a C=C bond in (±)-shonanol, the quantitative isostructurality index calculations indicate that the structures are not isostructural. Intermolecular O—H…O hydrogen bonds between pairs of molecules in the compounds related by center of inversion lead to characteristic dimers forming R

The X-Ray Crystal Structure of 1,2-3,4-Di-O-isopropylidene-4-C-methylthiomethoxy-β-L-arabino-hexoseptanos-5-ulose

1990 ◽  
Vol 43 (12) ◽  
pp. 2083 ◽  
Author(s):  
DC Craig ◽  
VJ James ◽  
JD Stevens
Keyword(s):  
Crystal Structure ◽  
Title Compound ◽  
Membered Ring ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

The crystal structure of the title compound (1) has been determined by X-ray diffraction. Crystals of (1) are orthorhombic, space group P21212 with a 11.425(1), b 24.916(1), c 5.8952(3)Ǻ, Z 4. Refinement on 1675 observed reflections measured with Cu Kα radiation converged at R 0.034. The seven- membered ring adopts a boat conformation in which the pseudo plane of symmetry passes through the ring oxygen.

Synthesis, characterization, and x-ray crystal structure of tris-isothiocyanato complexes of the yttrium(III) and europium(III) ions with a six-nitrogen-donor macrocyclic ligand

Polyhedron ◽  
1989 ◽  
Vol 8 (17) ◽  
pp. 2157-2167 ◽  
Author(s):  
G. Bomibieri ◽  
F. Benetollo ◽  
A. Polo ◽  
L. De Cola ◽  
W.T. Hawkins ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Macrocyclic Ligand ◽  
X Ray ◽  
Nitrogen Donor

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.

Unexpected Pyrolytic Behaviour of Substituted Benzo[c]thiopyran and Thieno[2,3-c]thiopyran S,S-dioxides

2014 ◽  
Vol 67 (9) ◽  
pp. 1288 ◽  
Author(s):  
R. Alan Aitken ◽  
Clémence Hauduc ◽  
M. Selim Hossain ◽  
Emily McHale ◽  
Adrian L. Schwan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ring Expansion ◽  
Hydrogen Atom Transfer ◽  
Membered Ring ◽  
X Ray ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis ◽  
Higher Temperature ◽  
Intramolecular Hydrogen ◽  
Carbonyl Products

Flash vacuum pyrolysis (FVP) of benzo[c]thiopyran S,S-dioxide (1) results in formation of indene and 2-vinylbenzaldehyde as previously described. A range of eight analogues with various substitution patterns are found to behave differently. In general, there is no extrusion of SO2 to give products analogous to indene, but unsaturated carbonyl products analogous to 2-vinylbenzaldehyde are formed in most cases by way of ring expansion to a 7-membered ring sultine, extrusion of SO, and intramolecular hydrogen atom transfer. Other processes observed include formation of anthracene via an isomeric 7-membered sultine with loss of SO, CO and methane or butane, and formation of 4-ethylidene-4,5-dihydrocyclobuta[b]thiophenes by way of SO loss, a radical rearrangement, and extrusion of acetone. The analogues with a halogen substituent at position 8 on the benzene ring require a higher temperature to react and give naphthalene resulting from net elimination of HX and SO2. The X-ray crystal structure of 1 is also reported.

Perfluorotetracyclobutacyclo-octatetraene; a planar eight-membered ring system; X-ray crystal structure

1981 ◽  
pp. 526 ◽  
Author(s):  
Frederick W. B. Einstein ◽  
Anthony C. Willis ◽  
William R. Cullen ◽  
Robert L. Soulen
Keyword(s):  
Crystal Structure ◽  
Ring System ◽  
Membered Ring ◽  
X Ray

Monomeric and polymeric nickel complexes of malate: X-ray crystal structure of polymeric homochiral S-malato nickel(II), [Δ-Ni(S-Hmal)(H2O)2]n·nH2O

Polyhedron ◽  
2002 ◽  
Vol 21 (7) ◽  
pp. 787-790 ◽  
Author(s):  
Zhao-Hui Zhou ◽  
Jian-Jun Ye ◽  
Yuan-Fu Deng ◽  
Geng Wang ◽  
Jing-Xing Gao ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Nickel Complexes ◽  
X Ray

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.

Cobalt(III) Complexes of the 10-Membered Macrocycle 1,4,7-Triazacyclodecane. The Structure of trans-Bis(1,4,7-triazacyclodecane)cobalt(III) Perchlorate

1993 ◽  
Vol 46 (12) ◽  
pp. 1955 ◽  
Author(s):  
TW Hambley ◽  
TW Hambley ◽  
GH Searle ◽  
GH Searle
Keyword(s):  
Crystal Structure ◽  
Membered Ring ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Lengths

The crystal structure of trans-[Co( tacd )2](ClO4)3 has been determined by X-ray diffraction methods and refined to a residual of 0.054 for 2477 independent observed reflections. The crystals are monoclinic, P 21/c, a 18.627(2), b 9.3438(5), c 16.057(2)Ǻ, β 119.45(2)°. Two complex cations are located at centres of symmetry and the ligands adopt λ,δ,chair conformations. Bond lengths from cobalt to nitrogen atoms in the six- membered ring (average 1.995 Ǻ) are significantly longer than those only associated with five- membered rings (average 1.961 Ǻ).

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