Crystal and molecular structure of potassium p-nitrophenolate monohydrate: Substituent effect on geometry of the ring in p-substituted nitrobenzene derivatives

1990 ◽  
Vol 55 (1) ◽  
pp. 165-179 ◽  
Author(s):  
T. M. Krygowski ◽  
I. Turowska-Tyrk
Keyword(s):  
Molecular Structure ◽  
Substituent Effect ◽  
Crystal And Molecular Structure ◽  
Resonance Effect ◽  
Resonance Structure ◽  
X Ray Diffraction ◽  
Quinoid Form ◽  
Full Charge ◽  
Hose Model

The crystal and molecular structure of potassium p-nitrophenolate monohydrate has been determined by X-ray diffraction methods giving R = 0.050. The through resonance effect between -O- and -NO2 groups resulted in a significant deformation of the ring geometry. Application of the HOSE model yielded in determination of the resonance structure contributions and offered an argument against the classical view of the through resonance effect: percentage contribution of quinoid form with full charge transfer from -O- to -NO2 was found to be the least significant of all four possible quinoid structures. Contributions of quinoid and benzenoid structures plotted against σ+ or σp constants for 14 p-systems give a reasonable linear dependence. Application of the additive scheme of substituent effect to the same series of compounds proved a strong reasonance effect from electron donating substituents and a much weaker one (and constant in the whole series) from the nitro group.

Preparation and structure of 4-(dimethylamino)thiopivalophenone – intermolecular interactions in the crystal

2019 ◽  
Vol 74 (11-12) ◽  
pp. 825-831
Author(s):  
Jürgen Voss ◽  
Dirk Buddensiek ◽  
Gunadi Adiwidjaja
Keyword(s):  
Molecular Structure ◽  
Carbon Disulfide ◽  
Quantum Chemical ◽  
Electron Distribution ◽  
Significant Contribution ◽  
Crystal And Molecular Structure ◽  
Resonance Structure ◽  
X Ray Diffraction ◽  
Torsion Angles ◽  
X Ray

Abstract4-(Dimethylamino)thiopivalophenone was prepared from 4-bromo-N,N-dimethylaniline, pivalonitrile and carbon disulfide. Its crystal and molecular structure was determined by single-crystal X-ray diffraction. The experimentally determined bond distances, bond angles and torsion angles are indicative of a significant contribution of a dipolar (“quinodimethane”) resonance structure to the electron distribution in the molecule. Quantum chemical calculations corroborate these results. The calculations, furthermore, provide an explanation of the arrangement of the molecules in the crystal.

Determination of the structure of bis(propyldithiocarbamate)nickel(II)

1990 ◽  
Vol 55 (4) ◽  
pp. 1010-1014 ◽  
Author(s):  
Jiří Kameníček ◽  
Richard Pastorek ◽  
František Březina ◽  
Bohumil Kratochvíl ◽  
Zdeněk Trávníček
Keyword(s):  
Molecular Structure ◽  
Title Compound ◽  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
Planar Configuration ◽  
Compound C ◽  
Heavy Atom Method

The crystal and molecular structure of the title compound (C8H16N2NiS4) was solved by the heavy atom method and the structure was refined anisotropically to a final R factor of R = 0.029 (wR = 0.037) for 715 observed reflections. The crystal is monoclinic, space group P21/c with a = 948.3(2), b = 776.9(2), c = 1 167.4(2) pm, β = 125.14(2)°, Z = 2. The molecule contains two four-membered NiSCS rings of approximately planar configuration with the Ni atom situated at a centre of symmetry. The molecules are arranged in chains along the c-axis of the unit cell.

Crystal and molecular structure of diorganoammonium oxalatotrimethylstannate, [R2NH2][Me3Sn(C2O4)] (R=i-Bu, cyclohexyl)

2011 ◽  
Vol 34 (5-6) ◽  
pp. 127-130 ◽  
Author(s):  
Yaya Sow ◽  
Libasse Diop ◽  
Kieran C. Molloy ◽  
Gabrielle Kociok-Köhn
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonds ◽  
Diffraction Study ◽  
Crystal And Molecular Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Trans Complex ◽  
A Chain ◽  
Distorted Trigonal Bipyramidal

Abstract The title compounds [R2NH2][C2O4SnMe3](R=i-Bu, Cy), in which tin atoms adopt a distorted trigonal bipyramidal configuration, have been prepared and submitted to an X-ray diffraction study. These compounds have been obtained from the reaction of (Cy2NH2)2C2O4·H2O or (i-Bu2NH2)2C2O4 with SnMe3Cl. In both [R2NH2][C2O4SnMe3] compounds, the trans complex has an almost regular trigonal bipyramidal geometry around the tin atom. The SnMe3 residues are connected as a chain with bridging oxalate anions in a trans-SnC3O2 framework, the oxygen atoms being in axial positions. The cations connect linear adjacent chains through NH…O hydrogen bonds giving layered structures.

Sign in / Sign up

Export Citation Format

Share Document