Folded discotic dimers

Bozek, Kevin J. A.; Williams, Vance E.

doi:10.1039/c4sm01116c

Cited by 17 publications

(22 citation statements)

References 39 publications

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“…The linear alkyl esters 2b – f and hydroxy-terminated esters 6a and 6c were prepared according to the method previously reported for 6b [12]. The acid 1 was first converted to its acid chloride using oxalyl chloride in the presence of dimethylformamide; subsequent treatment of this acid chloride with an excess of the appropriate alcohol afforded the target esters in moderate to good yields (33%–85%) after final purification.…”

Section: Resultsmentioning

confidence: 99%

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Liquid Crystalline Esters of Dibenzophenazines

Bozek

Saint-Martin

et al. 2015

Materials

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A series of esters of 2,3,6,7-tetrakis(hexyloxy)dibenzo[a,c]phenazine-11-carboxylic acid was prepared in order to probe the effects of the ester groups on the liquid crystalline behavior. These compounds exhibit columnar hexagonal phases over broad temperature ranges. Variations in chain length, branching, terminal groups, and the presence of cyclic groups were found to modify transition temperatures without substantially destabilizing the mesophase range.

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Section: Resultsmentioning

confidence: 99%

“…Column chromatography was performed using silica gel 60 (230–400 mesh) purchased from Silicyle Inc. (Quebec City, Canada). The carboxylic acid derivative, 1 [11] and esters 2a [11] and 6b [12] were prepared according to previously published methods.…”

Section: Methodsmentioning

confidence: 99%

Liquid Crystalline Esters of Dibenzophenazines

Bozek

Saint-Martin

et al. 2015

Materials

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“…For discotic dimers, the edge‐on conformation could be of two types, namely, folded‐ and unfolded‐form as shown in Figure C. Particularly, if the two discotic cores of the dimer are connected by flexible spacer, they tend to fold due to the strong π‐π interactions . In the present work, the TpImTp dimer molecule is symmetric and the experimentally observed A o values only indicate an edge‐on conformation without clarifying whether or not it is folded.…”

Section: Resultsmentioning

confidence: 61%

“…Particularly, if the two discotic cores of the dimer are connected by flexible spacer, they tend to fold due to the strong p-p interactions. [36][37][38] In the present work, the TpImTp dimer molecule is symmetric and the experimentally observed Ao values only indicate an edge-on conformation without clarifying whether or not it is folded. In order to study the folding behavior of the molecule, firstprinciples calculations were carried out based on densityfunctional theory (DFT) at B3LYP/6-311G** level and basis set.…”

Section: Langmuir-blodgett (Lb) Film Depositionmentioning

confidence: 90%

Supramolecular Self‐Assembly of Ionic Discotic Liquid Crystalline Dimer with DNA at Interfaces

et al. 2018

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Nanoarchitectonics through ionic self‐assembly at interfaces is an attractive approach to obtain advanced functional materials. Here, a novel discotic dimer‐DNA complex hybrid system has been investigated at air‐water and air‐solid interfaces. The ionic discotic liquid crystalline dimer consisted of two triphenylene cores linked via alkyl spacer with a imidazolium moiety. At air‐water interface, the dimer formed a stable monolayer with a reversible collapse. The surface manometry results suggested that the condensed phase of the monolayer consisted of molecules arranged in an edge‐on conformation. To understand the folding behavior of the molecules, DFT calculations were carried out which showed that the quantum chemically optimized folded‐form of the molecule was electronically more stable than its unfolded‐form. Upon adding DNA to the subphase, a complex monolayer was formed with enhanced stability as was indicated by increased collapse pressure and decreased limiting area. Importantly, this complexation enabled an efficient and stable multilayer formation on silicon substrates with layers as many as 40. Since both DNA and discotic dimer molecules share common properties of one‐dimensional charge transport with compatible structures, this complex film could serve as a model system for organic electronics.

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“…[6] However,i nc ontrast to dendritic,a mphiphilic, H-bonded, or star-shaped mesogens, [7] most discoticl iquid crystals, carrying ac entralr igid aromatic or heteroaromatic core functionalized with flexible peripheral alkyl side chains, enter their mesophases at elevated temperatures. [8] Thus, meltingp oints that are often far above room temperature and clearing points close to the decomposition temperature, limit furthera pplication in devices,f or example, ferroelectric switches. [9] Severals trategies have therefore been developed to circumvent this problem and to make room-temperaturem esophases possible, for example, the replacement of n-alkoxy groups by thioethers lowered the melting transition temperature.…”

Section: Introductionmentioning

confidence: 99%

δ‐Methyl Branching in the Side Chain Makes the Difference: Access to Room‐Temperature Discotics

et al. 2016

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Although discotic liquid crystals are attractive functional materials, their use in electronic devices is often restricted by high melting and clearing points. Among the promising candidates for applications are [15]crown-5 ether-based liquid crystals with peripheral n-alkoxy side chains, which, however, still have melting points above room temperature. To overcome this problem, a series of o-terphenyl and triphenylene [15]crown-5 ether derivatives was prepared in which δ-methyl-branched alkoxy side chains of varying lengths substitute the peripheral linear alkoxy chains. The mesomorphic properties of the novel crown ethers were studied by differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction. δ-Methyl branching indeed lowers melting points resulting in room-temperature hexagonal columnar mesophases. The mesophase widths, which ranged from 87 to 30 K for o-terphenyls, significantly increased to 106-147 K for the triphenylenes depending on the chain lengths, revealing the beneficial effect of a flat mesogen, due to improved π-π interactions.

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Folded discotic dimers

Cited by 17 publications

References 39 publications

Liquid Crystalline Esters of Dibenzophenazines

Liquid Crystalline Esters of Dibenzophenazines

Supramolecular Self‐Assembly of Ionic Discotic Liquid Crystalline Dimer with DNA at Interfaces

δ‐Methyl Branching in the Side Chain Makes the Difference: Access to Room‐Temperature Discotics

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