Star-shaped conjugated compounds forming nematic discotic systems

Meier, Herbert; Lehmann, Matthias; Holst, Hans Christof; Schwöppe, Dirk

doi:10.1016/j.tet.2004.06.012

Cited by 79 publications

(36 citation statements)

References 26 publications

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“…[22,23] Molecules of the first group are also called mesogen trimers. This term is, however, not sufficiently precise, since linear, branched and bent trimers exist.…”

Section: Classification and Motivationmentioning

confidence: 99%

“…There are a few examples including star molecules based on oligophenylene, [22b, 28] oligophenyleneethynylene [22g] and oligophenyleneethenylene arms. [23,38] . For molecules with short arms, the void between them is small and a space-filling model demonstrates the approximate disc-shape in the case of 6-9 peripheral flexible chains (Figure 4).…”

Section: Principal Conformations and Molecular Structurementioning

confidence: 99%

“…The resulting nematic LC glasses are interesting for large area nonabsorbing polarisers, optical notch filters and reflectors and for polarized fluorescent films. [65] Highly fluorescent materials were obtained from triazine and benzene derivatives [66,23,39] and benzene-1,3,5-triscarboxamides. [67] The latter forms a fluorescent gel, in which only the hydrogen-bonded assemblies of the star-molecules prevent the fast nonradiative relaxation.…”

Section: Supramolecular Self-assemblymentioning

confidence: 99%

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Star Mesogens (Hekates)—Tailor‐Made Molecules for Programming Supramolecular Functionality

Lehmann

2009

Chemistry A European J

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106

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This concept article focuses on the simplest branched liquid crystalline (LC) molecules--the three-armed mesogens with arms symmetrically linked to the core. They are basic but fascinating mesogens for the exploration of self-assembling processes into complex, functional, soft materials. Quite a large number of elements of diversity provide the possibility to synthetically program such star-shaped molecules and to control phase formation, if aggregation processes are fully understood. Recently, ABC-cores opened the way to non-symmetric mesogens and, therefore, to the concept of multifunctional materials with defined nanostructures. In the article this outstanding family of mesogens is classified, their peculiar molecular structure and self-assembly are discussed and potential applications are presented, in which this type of mesogen may be beneficial.

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“…[22,23] Molecules of the first group are also called mesogen trimers. This term is, however, not sufficiently precise, since linear, branched and bent trimers exist.…”

Section: Classification and Motivationmentioning

confidence: 99%

Section: Principal Conformations and Molecular Structurementioning

confidence: 99%

Section: Supramolecular Self-assemblymentioning

confidence: 99%

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Star Mesogens (Hekates)—Tailor‐Made Molecules for Programming Supramolecular Functionality

Lehmann

2009

Chemistry A European J

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106

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“…Some time ago we reported on the preparation and the properties of 2,4,6-tristyryl-1,3,5-triazines and their higher homologues having oligo (1,4-phenylenevinylene) [OPV] chains. [8][9][10] We are studying now star-shaped systems with a 1,3,5-triazine core and three OPV chains which bear ter-minal dialkylamino groups. This structure concept conveys the compounds an octupolar character with a strong pushpull effect in each of the three arms.…”

Section: Introductionmentioning

confidence: 99%

Star‐Shaped Push‐Pull Compounds Having 1,3,5‐Triazine Cores

2006

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The 1,3,5-triazines 9-11 having OPV chains in the 2-, 4-and 6-position represent star-shaped compounds which exhibit strong push-pull effects. Their long-wavelength absorption S 0 Ǟ S 1 is characterized by an intramolecular charge transfer (ICT) from the dialkylamino group as electron donor D via the conjugated chain to the 1,3,5-triazine core as electron acceptor A. Protonation of the dialkylamino group removes the donor capability, whereas protonation of the 1,3,5-triazine ring enhances the acceptor strength. Thus, the prevailing protonation site has a crucial influence on the push-pull effect and the ICT. The transition energies ∆E (S 0 Ǟ S 1 ) pass

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“…Reports on areno-condensed annulenes 5 [5], star-shaped stilbenoid compounds 6 [6][7][8][9][10][11] and stilbenoid dendrimers 7 [12][13][14][15][16] are given elsewhere; this chapter is focused on linear systems, namely on oligo(1,4-phenylenevinylene)s 2 and oligo-(1,4-phenyleneethynylene)s 1.…”

Section: Introductionmentioning

confidence: 99%