Infrared absorption study of hexapentyloxytriphenylene A discotic liquid crystal

Kruk, G.; Kocot, A.; Wrzalik, R.; Vij, J. K.; Karthaus, Olaf; Ringsdorf, Helmut

doi:10.1080/02678299308027757

Cited by 51 publications

(15 citation statements)

References 28 publications

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“…The IR spectra of com pounds 2c-j synthesized in this work agree well with the published data. 19 A comparison of the IR spectra of compounds 1k and 2k confirmed additionally the structure of triphenyl (Table 3). The absorption bands in the re gions of stretching (2960-2850 cm -1 ) and bending (1465-1392 cm -1 ) vibrations of the Me and CH 2 groups confirm that compound 2k contains hydrocarbon sub stituents.…”

supporting

confidence: 55%

Synthesis and specific features of mesomorphic behavior of new polysubstituted triphenylenes

Zemtsova

Zheleznov

2004

Russ Chem Bull

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Previously unknown 2,3,6,7,10,11 hexakis(dodecyloxy)triphenylene and (tetradecyl oxy)triphenylene were synthesized. The structures of the synthesized compounds were proved by elemental analysis and spectral methods. Polymesomorphism was found for the first time and studied for substances of the hexaalkoxytriphenylene homologic series, as well as liotropic mesomorphism in a series of organic solvents.

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supporting

confidence: 55%

Synthesis and specific features of mesomorphic behavior of new polysubstituted triphenylenes

Zemtsova

Zheleznov

2004

Russ Chem Bull

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“…=D i of liquid crystal sample with homeotropic orientation for IR absorption band m ¼ 1613.5 cm À1 . It corresponds to the C-C aromatic stretching vibrations of phenyl rings of the molecular core, which are polarized in the plane of these rings [2]. For given band parameter S b is equal to À1=2.…”

Section: Resultsmentioning

confidence: 99%

“…The information about the long-range orientational and translational order parameters of the molecules and their fragments improve our understanding of columnar discotic structures. The study of dichroism of polarized IR bands corresponding to the normal molecular modes allows us to determine the order parameters of the molecular fragments [2], as well as the parameters of the anisotropic local field of a light wave acting on these fragments [3]. Besides, the local field effects cause the mixing of molecular excitations for adjacent absorption bands and have to modify spectral methods for experimental determination of these parameters in discotic LC's [4].…”

Section: Introductionmentioning

confidence: 99%

Orientational Ordering and Polarizability of Molecules in the Columnar Phase of Discotic Liquid Crystal

Gunyakov

Shibli

2004

Molecular Crystals and Liquid Crystals

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The structural and molecular-optical properties of the columnar discotic liquid crystal 2,3,6,7,10,11-hexaheptyloxytriphenylene were studied by using of refractometric and infrared (IR) measurements. Temperature dependence of the orientational order parameter S with allowance for the anisotropy of the local field of a light wave and mixing of molecular excitations was evaluated for C-C aromatic stretching band. The local field parameters have been evaluated within approximation of the effective spheroidal Lorentz cavity model. The anisotropy c a and the mean value c of the molecular polarizability of triphenylene were investigated for several wavelengths. The experimentally observed changes of molecular-optical properties in columnar phase seem to be affected by the induction mechanism of the variety of the molecular polarizability with increasing of S, proposed previously for calamitic liquid crystals. Furthermore, these properties are not related to the effects of aliphatic tails disordering.

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“…The influence of substrate structure on the orientation of the columnar liquid crystals placed between two plates has been recently demonstrated [8]. On glassy surfaces, e.g., triphenylene liquid crystals align homeotropically [9]. Polycrystalline substrate aligns central disks at an angle tilted to the surface [10].…”

Section: Discussionmentioning

confidence: 99%

Effects of Order on Spectral Properties of Discotic Liquid Crystal Heptyloxydibenzopyrene

Uznański

1998

Acta Phys. Pol. A

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The spectral properties of discotic heptyloxydibenzopyrene were studied by UV-VIS absorption, fluorescence, and infrared spectroscopy as a function of temperature in two different types of spectroscopic cells. The molecule was found to be a sensitive spectroscopic probe of molecular orientation on a surface. Capillary-filled cells caused the liquid crystal to assume a parallel orientation with respect to the surface, whereas spin-coating caused the orientation of columns to be statistically more nonuniform. It was shown from the spectroscopic studies that the molecular orientation changed on going from crystal to liquid crystalline state and a conclusion was drawn that bulk molecular alignment of columnar phase was defined by an interface imposed by an external surface.

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Infrared absorption study of hexapentyloxytriphenylene A discotic liquid crystal

Cited by 51 publications

References 28 publications

Synthesis and specific features of mesomorphic behavior of new polysubstituted triphenylenes

Synthesis and specific features of mesomorphic behavior of new polysubstituted triphenylenes

Orientational Ordering and Polarizability of Molecules in the Columnar Phase of Discotic Liquid Crystal

Effects of Order on Spectral Properties of Discotic Liquid Crystal Heptyloxydibenzopyrene

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