X-ray diffraction study of p-(alkoxybenzylidene)-p′-toluidines C2H5O-C6H4-CH=N-C6H4-CH3 and C4H9O-C6H4-CH=N-C6H4-CH3

Кузьмина, Л. Г.; Kucherepa, N. S.; Rodnikova, M. N.

doi:10.1134/s1063774508060175

Cited by 9 publications

(3 citation statements)

References 6 publications

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“…It is clearly seen that the crystal space is partitioned into aromatic and aliphatic regions. The aromatic regions are closely packed, whereas the aliphatic regions are character ized by loose packing, which is typical of LC com pounds and is a prerequisite for the mesophase forma tion [2][3][4][5][6][7].…”

Section: Crystal Packingmentioning

confidence: 99%

“…Hence, knowledge of the molecular packing in the crystal structure can provide insight into the structure of the mesophase of this compound and the mechanism of phase transitions. The approach to investigating mesophases and phase transitions based on crystal packing analysis was developed in [2][3][4][5][6][7] for represen tatives of homologous series of alkyloxybenzoic acids, alkylbenzoic acids, alkyloxybenzylidene toluidines, alkylcyanobiphenyls, and alkyloxycyanobiphenyls. This approach is based on the concept of self organi zation (or self assembly) of structured ensembles in a liquid phase via weak directional interactions (second ary bonds), which is one of the basic concepts of supramolecular chemistry.…”

Section: Introductionmentioning

confidence: 99%

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Crystal and molecular structure of n-hexyloxyphenyl n-octyloxybenzoate

et al. 2012

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The X ray crystal structure of n hexyloxyphenyl n octyloxybenzoate C 8 H 17 O-C 6 H 4 -COO-C 6 H 4 -OC 6 H 13 , which is a liquid crystal compound, was determined. This compound forms smectic and nematic phases upon melting. A crystal packing analysis revealed the following two types of structure forming elements in the centrosymmetric pairs of molecules: a π stacking interaction and a C-H···π system interaction. In the pairs of molecules linked by the latter type of interactions, there are two such interactions per pair, whereas one interaction occurs per pair of molecules linked by a π stacking interaction. Hence, the former pair of molecules is more stabilized through weak directional interactions than the latter pair.

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Section: Crystal Packingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Crystal and molecular structure of n-hexyloxyphenyl n-octyloxybenzoate

et al. 2012

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“…These supramolecular ensembles determine the degree of structuring of the melt and set the LC properties of the system. Previ ously we successfully used this ideology to analyze the compounds of a homologous series of 4 alkyloxyben zoic acid [4] and p (n alkyloxybenzylidene) n' tolui dine [5][6][7], having established a relationship between the form of the mesophase produced by these com pounds and the specific features of their crystal pack ing. On this basis it was proposed to describe the phase transitions with the participation of the mesophase using the representation of the crystal and mesophase structures in the form of graphs.…”

Section: Introductionmentioning

confidence: 99%

Mesophase design: II. Molecular structure and crystal packing of 4-alkyloxycyanobiphenyls

2012

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A joint analysis of the molecular geometry and crystal packings of the members of a homologous series of 4 alkyloxycyanobiphenyl C n H 2n + 1 -O-C 6 H 4 -C 6 H 4 -CN with n = 5-12 does not reveal a direct relationship between the molecular geometry and mesogenic properties of these compounds. The crystal packings of all of them are built from alternating loose aliphatic and dense aromatic regions. The closely packed aromatic regions of crystals exhibit weak intermolecular directed interactions of different natures which are responsible for the occurrence of the mesophase. The type of mesophase depends on the number s of structure forming elements, the ratio of their energies (if s > 1), and the melting temperature of the com pound. A graph system is used to describe the crystal packings and the mesophase. It is shown that, although the mesophase graph is similar to the crystal graph, they may differ somewhat, because some symmetric lim itations (for example, lattice) on the molecular associate structure are removed in the melt.

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