Anthraquinone-based discotic liquid crystals: new monomers and dimers

Prasad, Veena; Roy, Arun; Nagaveni, N.; Gayathri, K.

doi:10.1080/02678292.2011.610525

Cited by 17 publications

(5 citation statements)

References 22 publications

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“…The XRD pattern of the xerogel (Figure b, Table in SI) showed two small peaks in the small-angle region (2θ < 3°) corresponding to d spacings of 63.1 and 33.3 Å. The ratio of these two peaks is close to 1:0.5 and can be fitted into 100 and 200 reflections arising from the lamellar (D L ) phase, which is rarely observed. − Further into the middle-angle region (2θ ≈ 8°), a small peak corresponding to a d spacing of 10.51 Å was observed, which can be asigned to the 600 reflection from the lamellar phase. Additionally, a diffuse peak in the wide-angle region (2θ = 20.3°) corresponding to a d spacing of 4.38 Å was observed that corresponds to the packing of alkyl tails (Figure b).…”

Section: Resultsmentioning

confidence: 97%

Liquid-Crystalline Star-Shaped Supergelator Exhibiting Aggregation-Induced Blue Light Emission

et al. 2016

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A family of closely related star-shaped stilbene-based molecules containing an amide linkage are synthesized, and their self-assembly in liquid-crystalline and gel states was investigated. The number and position of the peripheral alkyl tails were systematically varied to understand the structure-property relation. Interestingly, one of the molecules with seven peripheral chains was bimesomorphic, exhibiting columnar hexagonal and columnar rectangular phases, whereas the rest of them stabilized the room-temperature columnar hexagonal phase. The self-assembly of these molecules in liquid-crystalline and organogel states is extremely sensitive to the position and number of alkoxy tails in the periphery. Two of the compounds with six and seven peripheral tails exhibited supergelation behavior in long-chain hydrocarbon solvents. One of these compounds with seven alkyl chains was investigated further, and it has shown higher stability and moldability in the gel state. The xerogel of the same compound was characterized with the help of extensive microscopic and X-ray diffraction studies. The nanofibers in the xerogel are found to consist of molecules arranged in a lamellar fashion. Furthermore, this compound shows very weak emission in solution but an aggregation-induced emission property in the gel state. Considering the dearth of solid-state blue-light-emitting organic materials, this molecular design is promising where the self-assembly and emission in the aggregated state can be preserved. The nonsymmetric design lowers the phase-transition temperatures.The presence of an amide bond helps to stabilize columnar packing over a long range because of its polarity and intermolecular hydrogen bonding in addition to promoting organogelation.

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Section: Resultsmentioning

confidence: 97%

Liquid-Crystalline Star-Shaped Supergelator Exhibiting Aggregation-Induced Blue Light Emission

et al. 2016

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“…Prasad et al compared monomeric and dimeric rufigallol derivatives with Col h mesophases . As recently reported, the presence of short branched side chains in rufigallols still leads to Col h phases albeit with a small temperature range …”

Section: Classes Of Compoundsmentioning

confidence: 99%

“…The structure of the lamellar mesophase is still not completely understood. Figure 5 illustrates a possible arrangement proposed by Sakashita et al 52 Recently lamellar discotic phases were observed for triphenylene silanes by Mansueto et al 53 and in dimeric discotic mesogens by Prasad et al 54 and Ong et al 55…”

Section: Structures Of Discotic Liquid Crystals 21 Basic Structuresmentioning

confidence: 99%

Discotic Liquid Crystals

et al. 2015

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“…In particular, liquid crystal dimers proved to be a rich source of new types of intercalated smectic phases (see, for example,references [8][9][10][11][12]) and, rare and unusual phase transition sequences (see, for example, references [13,14]). More recently, interest has focussed on, for example, their flexoelectric behaviour, [15][16][17] T-and H-shaped dimers, [18][19][20][21] non-alkyl spacers, [22][23][24] cholesterylbased dimers, [25][26][27][28][29][30] discotic dimers, [31][32][33] carbohydrate-based dimers, [34] bent core-calamitic nonsymmetric dimers, [35,36] the effects of linking groups, [37] dimers containing new types of mesogenic units and functionalities, [38][39][40][41][42][43][44][45][46] as well as on higher oligomers. [47][48][49][50] Perhaps the most exciting recent discovery involving liquid crystal dimers, however, has been the observation of nematic-nematic transitions for a small number of odd-membered dimers.…”

Section: Introductionmentioning

confidence: 99%