Stress the twofold axis of the threo isomer

1986 ◽  
Vol 63 (6) ◽  
pp. 511 ◽  
Author(s):  
D. Tavernier
Keyword(s):  
Twofold Axis ◽  
Threo Isomer

scholarly journals 2-[N-(4-{4-[(2-Hydroxy-5-methoxybenzylidene)amino]benzyl}phenyl)carboximidoyl]-4-methoxyphenol

2012 ◽  
Vol 68 (4) ◽  
pp. o1141-o1141
Author(s):  
Ali Ourari ◽  
Lotfi Baameur ◽  
Gilles Bouet ◽  
Magali Allain
Keyword(s):  
Hydrogen Bond ◽  
Schiff Base ◽  
Dihedral Angle ◽  
Twofold Axis ◽  
Benzene Rings

In the title Schiff base, C29H26N2O4, the complete molecule is generated by a crystallographic twofold axis and is V-shaped. The planes of the benzene rings of the central diphenylmethane unit make a dihedral angle of 78.11 (4)° while adjacent benzene and 5-methoxysalicylidene rings are twisted with respect to each other by a dihedral angle of 11.84 (8)°. The Schiff base is in the enol–imino form and an intramolecular O—H...N hydrogen bond is observed.

Multinuclear NMR spectra of [Pt(L)Cl3]− (L = pyridine derivatives) complexes and crystal structure of trans-Pt(2,6-di(hydroxymethyl)pyridine)2Cl2•2H2O

1996 ◽  
Vol 74 (11) ◽  
pp. 2121-2130 ◽  
Author(s):  
Fernande D. , ◽  
Corinne Bensimon ◽  
André L. Beauchamp
Keyword(s):  
Crystal Structure ◽  
Pyridine Ring ◽  
Chemical Shifts ◽  
Bond Distance ◽  
Coupling Constants ◽  
Mirror Plane ◽  
Pyridine Derivative ◽  
Pyridine Derivatives ◽  
Pyridine Ligand ◽  
Twofold Axis

Complexes of the type [Pt(L)Cl3]− (L = pyridine derivative) were synthesized and studied by 13C and 195Pt NMR spectroscopies. The 195Pt signals were observed between −1720 and −1897 ppm. No correlation between the δ(Pt) and the pKa of the protonated pyridine derivatives was found. The chemical shifts vary with the substituents on the pyridine ligand. Compounds with substituents in ortho positions were observed at lower fields, except for complexes containing hydroxy or amine groups. The latter compounds were observed at higher fields, close to the signals of the Pt-unsubstituted pyridine compound. These results were explained in terms of the solvent effect. The chemical shifts δ(C) and the coupling constants J(13C–195Pt) were measured and the results interpreted with a view of obtaining information on the nature of the Pt—N bond. The possibility of π-bonding between platinum and the pyridine ligand is examined. The conformation of the pyridine ring in relation to the platinum plane and the energies of the rotation barriers around the Pt—N bond in these types of platinum(II) complexes are briefly discussed. The crystal structure of trans-Pt(2,6-(HOCH2)2py)2Cl2•2H2O was determined by X-ray diffraction. The compound is monoclinic, C2/m, a = 7.022(6), b = 15.646(13), c = 8.344(10) Å, β = 93.35(8)°, Z = 2, R = 0.037. The platinum atom is located at the junction of the twofold axis and the mirror plane, the N atoms and the para-C atom of the pyridine ring are situated on the twofold axis, and the chloride ligands are on the mirror plane. The compound crystallizes with molecules of water, which are H-bonded to the hydroxy groups. The Pt—Cl bond distance is 2.306(2) Å, and that of the Pt—N bond is 2.041 (6) Å. The dihedral angle between the platinum and the pyridine planes is 79.8°. Key words: platinum, pyridine derivatives, NMR, crystal structure.

1,1′-Biphenyl-4,4′-diammonium bis(2-nitrobenzoate) dihydrate

2007 ◽  
Vol 63 (11) ◽  
pp. o4305-o4305
Author(s):  
Lin-heng Wei
Keyword(s):  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Twofold Axis ◽  
Molecular Salt

In the title hydrated molecular salt, C12H14N2 +·2C7H4NO4 −·2H2O, the complete cation is generated by a crystallographic twofold axis running perpendicular to the central C—C bond. The components give rise to an infinite three-dimensional framework via intermolecular N—H...O and O—H...O hydrogen bonds.

scholarly journals (Z)-3-[2-(2,4-Dinitrophenyl)hydrazin-1-ylidene]isobenzofuran-1(3H)-one dichloromethane hemisolvate

2014 ◽  
Vol 70 (4) ◽  
pp. o418-o418
Author(s):  
Palak Agarwal ◽  
Pragati Mishra ◽  
Nikita Gupta ◽  
Neelam ◽  
Priyaranjan Sahoo ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Benzene Ring ◽  
Dihedral Angle ◽  
Title Compound ◽  
Crystal Packing ◽  
Halogen Bond ◽  
Solvent Molecule ◽  
Twofold Axis ◽  
Bond Interaction ◽  
The Mean

In the title compound, 2C14H8N4O6·CH2Cl2, the dichloromethane solvent molecule resides on a crystallographic twofold axis. The mean plane of the phthalisoimide ring is oriented at a dihedral angle of 32.93 (12)° with respect to the nitro-substituted benzene ring. An intramolecular N—H...O hydrogen bond occurs. The crystal packing features a short Cl...O halogen-bond interaction [3.093 (3) Å].

Structure of the Tris(diallyldithiocarbamate)cobalt(III) Complex

1992 ◽  
Vol 57 (2) ◽  
pp. 332-338 ◽  
Author(s):  
Eleonóra Kellö ◽  
Jan Lokaj ◽  
Viktor Vrábel
Keyword(s):  
Least Squares ◽  
Metal Atom ◽  
Least Squares Method ◽  
Heavy Atom ◽  
Distorted Octahedron ◽  
Monoclinic System ◽  
Space Group ◽  
Twofold Axis ◽  
Diagonal Approximation ◽  
Heavy Atom Method

The structure of [Co{S2CN(CH2-CH=CH2)2}3] was determined by the heavy atom method, all nonhydrogen atoms being refined by anisotropic diagonal approximation using the least squares method to the value of R= 0.067 for 1 024 reflections with I ≥ 1.96σ(I). The substance is isostructural with [Fe{S2CN(CH2-CH=CH2)2}3], crystallizes in the monoclinic system, space group C2/c, lattice parameters a = 1.8763(9), b = 1.0209(5), c = 1.5402(7) nm, β = 106.18(4)°, Z = 4. Cobalt is coordinated by 3 dithiocarbamate ligands in the bidentate way, the average Co-S lenght is 0.2267(2) nm. The metal atom and two ligand atoms are located on the twofold axis. The CoS6 polyhedron is a trigonally distorted octahedron.

Bis[4-fluoro-N-(quinolin-8-yl)benzenesulfonamidato-κ2 N,N′]zinc(II) hemihydrate

2006 ◽  
Vol 62 (7) ◽  
pp. m1719-m1721 ◽  
Author(s):  
Luiz Everson da Silva ◽  
Antonio Carlos Joussef ◽  
Sabine Foro ◽  
Boris Schmidt
Keyword(s):  
Hydrogen Bonds ◽  
Water Molecule ◽  
Title Compound ◽  
Three Dimensional ◽  
Tetrahedral Geometry ◽  
Special Position ◽  
Twofold Axis ◽  
Distorted Tetrahedral Geometry ◽  
Dimensional Network

In the title compound, [Zn(C15H10FN2O2 S)2]·0.5H2O, the Zn atom has a distorted tetrahedral geometry, formed by the N atoms of the quinoline and the sulfonamide groups. The water molecule occupies a special position on a twofold axis. Intermolecular C—H...O hydrogen bonds to the sulfonyl O atoms link the molecules into a three-dimensional network.

2-Hydroxypropane-1,3-diammonium bis(phosphonato)zincate(II) hemihydrate

2007 ◽  
Vol 63 (11) ◽  
pp. m2779-m2779
Author(s):  
Andrew S. Holtby ◽  
William T. A. Harrison
Keyword(s):  
Hydrogen Bonds ◽  
Title Compound ◽  
Mirror Plane ◽  
Oh Groups ◽  
Positional Disorder ◽  
Twofold Axis ◽  
Compound C

In the title compound, (C3H12N2O)[Zn(HPO3)2]·0.5H2O, the inorganic macroanionic chain is built up from ZnO4 tetrahedra and HPO3 pseudo-pyramids sharing vertices. The organic dication shows positional disorder of its central –OH group in a 0.614 (7):0.386 (7) ratio. The components interact by way of O—H...O and N—H...O hydrogen bonds. The Zn atom lies on a crystallographic twofold axis and one C atom, the disordered O atoms of the –OH groups and the water O atom lie on a crystallographic mirror plane.

A fivefold interpenetrating diamondoid framework constructed by flexible dipyridyl and dicarboxylate ligands

2013 ◽  
Vol 69 (11) ◽  
pp. 1328-1331 ◽  
Author(s):  
Jun-Feng Wang ◽  
Wen-Jing Guo ◽  
Fan-Zheng Deng
Keyword(s):  
Water Molecule ◽  
Three Dimensional ◽  
Diacetic Acid ◽  
Coordination Environment ◽  
Twofold Axis

A novel three-dimensional CdIIcomplex, poly[aqua{μ2-1,4-bis[2-(pyridin-4-yl)ethenyl]benzene-κ2N:N′}[μ4-2,2′-(1,4-phenylene)diacetato-κ4O,O′:O′′,O′′′]cadmium(II)], [Cd(C10H8O4)(C20H16N2)(H2O)]n, has been prepared by hydrothermal assembly of Cd(NO3)2·4H2O, 1,4-bis[2-(pyridin-4-yl)ethenyl]benzene (1,4-bpeb) and 2,2′-(1,4-phenylene)diacetic acid (1,4-H2pda). Each CdIIcentre is located on a twofold axis in a distorted pentagonal bipyramidal coordination environment formed by one O atom from a water molecule, which lies on the same twofold axis, four O atoms from two different 1,4-pda ligands and two N atoms from two different 1,4-bpeb ligands. The CdIIcentres are bridged by the 1,4-bpeb and 1,4-pda ligands, which lie across centres of inversion. The three-dimensional net can be regarded as a diamondoid network by treating the CdIIatoms as nodes and the 1,4-bpeb and 1,4-pda ligands as linkers. The single net leaves voids that are filled by mutual interpenetration of four independent equivalent frameworks in a fivefold interpenetrating architecture.

Strukturchemie von Verbindungen des pentakoordinierten Siliciums. Das Bis(ethylendioxy)methylsilan-Anion / Structural Studies of Pentacoordinate Silicon. The Bis(ethylenedioxy)methylsilane Anion

1982 ◽  
Vol 37 (2) ◽  
pp. 195-197 ◽  
Author(s):  
Dietmar Schomburg
Keyword(s):  
Hydrogen Bonds ◽  
Silicon Atom ◽  
Trigonal Bipyramid ◽  
Structural Studies ◽  
Space Group ◽  
Bond Lengths ◽  
Twofold Axis ◽  
Pentacoordinate Silicon ◽  
Pentacoordinate Silicon Atom

Abstract Hexamethylendiammonium-bis(ethylenedioxy)methylsilane crystallizes in the hexagonal space group P6122, Z = 6 with a= 11.902(1), c = 30.148(4) A. The structure was refined to R - 0.041 using 2281 independent reflections. The geometry around the pentacoordinate silicon atom is between a trigonal bipyramid and a square pyramid. Oeq-Si-Oeq 136.0(1)°, Oax-Si-Oax 161.7(1)°. The Si-Oax bond lengths are 1.749(2) and 1.769(2) A, the Si-Oeq 1.711(2) and 1.735(2) A, Si-Ceq 1.876(3) A. The compound forms strong N-H ··· O hydrogen bonds between cation and anion. The cation lies on a crystallographic twofold axis

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