30 research outputs found
N-[2-(2-ChloroÂphenÂyl)-2-hydroxyÂethyl]propan-2-aminium hemioxalate
The asymmetric unit of the title compound, C11H17ClNO+·0.5C2O4
2â, consists of one N-[2-(2-chloroÂphenÂyl)-2-hydroxyÂethyl]propan-2-ammonium cation and one-half of a centrosymmetric oxalate anion. In the cation, the C/C/N plane of the ethylÂammonium group is almost perpendicular to the benzene ring, with a dihedral angle of 88.72â
(17)°. In the crystal structure, the two components are connected by OâHâŻO and NâHâŻO hydrogen bonds, forming a supraÂmolecular tape along the a axis. Between the tapes, a CâHâŻO interÂaction is observed
ChemInform Abstract: From para-Dimethoxybenzene Towards Crownbenzenophanes. Part 2. Synthesis, X-Ray Structure and Fluorescence Emission Properties of 1,3, 10,13,16,19,22-Heptaoxa(3,13)(28)paracyclophane and Its Complex with Sodium Cation.
Crystalline arrangement of some disc like compounds
Three triphenylene esters, disc-like molecules, belonging to a series of compounds, some of which show a new mesomorphic and thermotropic phase have been studied by X-ray diffraction. The crystal structure of one of these esters has been established. Molecules are associated in pairs with their triphenylene cores parallel and 3.43 Ă
. These dimers give columns arranged in hexagonal lattice.Trois esters du triphĂ©nylĂšne, molĂ©cules de type discoĂŻde appartenant Ă une sĂ©rie de composĂ©s, dont certains prĂ©sentent une phase mĂ©somorphe thermotrope nouvelle, ont Ă©tĂ© Ă©tudiĂ©s par diffraction des rayons X. La structure d'un de ces esters a Ă©tĂ© Ă©tablie. Les molĂ©cules s'associent en donnant des paires, leurs noyaux triphĂ©nylĂšne Ă©tant parallĂšles et Ă 3,43 Ă
l'un de l'autre. Ces dimÚres forment des colonnes arrangées suivant un réseau hexagonal
Molecular arrangement of mesogenic disc-like compounds : the hexa-n-alkoxy and hexa-n-alkanoyloxy triphenylenes
A theoretical study of homologous series of triphenylene hexaesters and hexaethers, disc-like mesogenic molecules, has been undertaken with semi-empirical methods. Preferential conformations of an isolated molecule, a pair of molecules and a set of molecules have been established For butyl and further homologues, hexaesters give irregular columns, resulting in piled pairs, with distances d and d' equal to 3.75 and 4.45 Ă
between neighbouring aromatic cores. On the other hand hexaethers give regular columns (d â 3.28 Ă
) of helicoidal type with a pitch equal to 14 Ă
. These results are in agreement with data from X-ray diffraction on the mesophase.L'Ă©tude thĂ©orique de sĂ©ries homologues d'hexaesters et d'hexaĂ©thers du triphĂ©nylĂšne, molĂ©cules discoĂŻdes mĂ©somorphogĂšnes a Ă©tĂ© effectuĂ©e par des mĂ©thodes semi-empiriques. Les conformations prĂ©fĂ©rentielles d'une molĂ©cule isolĂ©e, d'une paire de molĂ©cules et d'un ensemble de molĂ©cules ont Ă©tĂ© Ă©tablies. Au-delĂ du terme butylique, les hexaesters forment des colonnes irrĂ©guliĂšres, rĂ©sultant de l'empilement de paires, avec des distances d et d' de 3,75 et 4,45 Ă
entre plateaux aromatiques parallĂšles successifs. Les hexaĂ©thers, par contre, forment des colonnes rĂ©guliĂšres (d â 3,28 Ă
) de type hĂ©licoĂŻdal de pas Ă©gal Ă 14 Ă
. Les résultats sont en bon accord avec ceux déduits de la diffraction des rayons X par la mésophase
Molecular conformation and arrangement of a disc like compound by semi-empirical calculations
The 2, 3, 6, 7, 10, 11 hexahydroxy triphenylene hexapropylester, a disc like molecule belonging to a series of compounds, some of which show a new mesomorphic and thermotropic phase has been studied by semi-empirical conformational analysis. In the preferential conformation, propyl ester chains are alternatively situated about and under the triphenylene core, the ester group making an angle of 56° with this latter. Molecules are associated in very stable pairs, with a rather specific configuration. A molecular arrangement in columns is proposed.L'hexapropylester du 2, 3, 6, 7, 10, 11 hexahydroxytriphénylÚne, molécule discoide appartenant à une série de composés, dont certains présentent une phase thermotrope nouvelle a fait l'objet d'une étude conformationnelle par des méthodes semi-empiriques. La conformation préférentielle correspond à des chaßnes alternativement situées au-dessus et au-dessous du noyau triphénylÚne, le groupement ester faisant un angle de 56° avec ce dernier. Les molécules s'associent par paires trÚs stables correspondant à une configuration bien définie. Un arrangement des molécules en colonnes est proposé