- Highly Oriented Fibres of Discotic Liquid Crystals
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Highly aligned discotic liquid crystal fibres of hexa-alkoxytriphenylene (HET-n) and its ester derivative (HAT-n) can be drawn by a new strand technique; our synchrotron X-ray scattering study indicates the single crystal quality of these fibres.
- Chiang, Long Y.,Safinya, C. R.,Clark, N. A.,Liang, K. S.,Bloch, A. N.
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- A Flexible and Rational Synthesis of Substituted Triphenylenes by Palladium-catalysed Cross-coupling of Arylzinc Halides
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A new, flexible route to substituted triphenylenes has been developed which involves the preparation of terphenyls using a palladium-catalysed cross-coupling of arylzinc halides with 1,2-dihalogenobenzenes, followed by oxidative cyclisation of these terphenyls using ferric chloride.
- Borner, Ruth C.,Jackson, Richard F. W.
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- Oxidative cyclotrimerization of unsaturated compounds with DDQ and triflic acid: An efficient synthetic route to triply-fused benzene rings
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Intermolecular oxidative cyclotrimerization reactions of alkenes and aromatic compounds with DDQ and trifluoromethanesulfonic acid are described. Scholl-type oxidation reactions involving alkenes have not previously been demonstrated. Moreover, the DDQ/acid system has never been used for intermolecular oxidative cyclization reactions. This convenient, metal-free reagent system (DDQ/TfOH) is advantageous with respect to metal-based Scholl-type oxidants because it eliminates the possibility of halogenation of aromatic compounds as a competing side reaction.
- Cho, Hee Yeon,Scott, Lawrence T.
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- Aggregates of Hexakis(n-hexyloxy)triphenylene Self-Assemble in Dodecane Solution: Intercalation of (-)-Menthol 3,5-Dinitrobenzoate Induces Formation of Helical Structures
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Concentrated dodecane solutions of hexakis(n-hexyloxy)triphenylene form columnar aggregates as evidenced by optical spectroscopy.Addition of either ethyl 3,5-dinitrobenzoate, (+)-2'-octyl 3,5-dinitrobenzoate, (-)-2'-butyl 3,5-dinitrobenzoate, or (-)-menthol 3,5-dinitrobenzoate to these solutions results in the formation of charge-transfer complexes as shown by examination of their optical spectra.Investigation of the circular dichroism spectra of the charge-transfer complexes suggests that intercalation of the menthol ester in the columnar aggregate induces a helical twist to the structure.
- Gallivan, Justin P.,Schuster, Gary B.
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- A new strategy towards the synthesis of a room-temperature discotic nematic liquid crystal employing triphenylene and pentaalkynylbenzene units
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A new approach is reported for the design of a room-temperature discotic nematic (ND) liquid crystal (LC) dimer consisting of a triphenylene and a pentaalkynylbenzene unit linked via flexible alkyl spacers. The formation of the ND phase is realized most likely through folding of the dimeric molecule that prevent stacking between the triphenylene units, as suggested by modelling in the mesophase derived from X-ray scattering results and high-level DFT calculations.
- Gupta, Monika,Gupta, Santosh Prasad,Rasna,Adhikari, Debashis,Dhara, Surajit,Pal, Santanu Kumar
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p. 3014 - 3017
(2017/03/17)
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- TNF Induced Switching of Columnar Rectangular to Hexagonal Assemblies in a New Class of Triphenylene-Based Room Temperature Discotic Liquid Crystals
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A straightforward synthesis of triphenylene-based oligomeric systems that self-organize into room temperature columnar structures is presented. The compounds with longer spacer length (m = 10 and 12) exhibit columnar rectangular (Colr) mesophase whereas the compound with m = 8 exists in glassy Colr state. Interestingly, the Colr self-assembly of these compounds switches to columnar hexagonal (Colh) on doping the compounds with 2,4,7-trinitrofluorenone (TNF). For the dopant concentration of 1:1 with respect to native compound, an intermediate transition state between Colr and Colh phase was observed which completely transformed into the hexagonal phase on increasing the concentration to 1:2 (compound: TNF) and afterward. Both the Colr and Colh self-assemblies have been well resolved by detailed X-ray analysis. These kind of oligomeric compounds generally possess a combination of desirable alignment properties analogous to monomeric compounds and long-lived glassy states similar to that of polymeric mesogens. In addition, charge hopping behavior is expected to increase in these compounds due to donor-acceptor interactions. Overall, these compounds can find possible potential applications in semiconductor devices.
- Gupta, Monika,Gupta, Santosh Prasad,Pal, Santanu Kumar
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p. 8593 - 8602
(2017/09/22)
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- Triphenylene derivative and use thereof
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A triphenylene derivative of general formula (I) or general formula (II) which can be used as a component of liquid crystal medium and the use thereof are provided in the present invention. This compound can be used to form a negative discotic liquid crystal composition having a suitable temperature range of liquid crystal phase and a lower clearing point, which can be used in TFT liquid crystal display as an optical compensation film (cell) material.
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- Self-organization of star-shaped columnar liquid crystals with a coaxial nanophase segregation revealed by a combined experimental and simulation approach
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Fully consistent X-ray data and molecular dynamics simulations on new star-shaped liquid crystals yield two nanosegregated architectures with a coaxial stacking of two functional discotic units: tris(triazolyl)triazine and triphenylene. Analysis of lattice order along the principal axes reveals preferential staggered arrangement of the stacked molecules in the columnar assembly.
- Beltrán, Eduardo,Garzoni, Matteo,Feringán, Beatriz,Vancheri, Alberto,Barberá, Joaquín,Serrano, José Luis,Pavan, Giovanni M.,Giménez, Raquel,Sierra, Teresa
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p. 1811 - 1814
(2015/02/05)
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- Discotic liquid crystal-functionalized gold nanorods: 2- and 3D self-assembly and macroscopic alignment as well as increased charge carrier mobility in hexagonal columnar liquid crystal hosts affected by molecular packing and π-π interactions
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Gold nanorods functionalized with triphenylene-based discotic liquid crystal (LC) motifs show striking self-assembly behavior both on transmission electron microscopy (TEM) grids as well as in the bulk enforced by the π-π-stacking of triphenylene groups of adjacent nanorods. TEM images confirm that these discotic LC nanorods form ribbons of parallel-stacked nanorods several hundred nanometer long. The pursued silane conjugation approach to decorate the nanorods allows for the preparation of dispersions of the nanorods in the hexagonal columnar phases of parent discotic LCs, where the nanorods can be macroscopically aligned with almost 80% efficiency by a simple shearing protocol. Doping the parent host materials with about 1% by weight of the discotic LC-capped nanorods also reduces the lattice parameter and the intracolumnar packing, which gives rise to enhanced charge carrier mobility in these hosts as determined by time-of-flight measurements.
- Feng, Xiang,Sosa-Vargas, Lydia,Umadevi,Mori, Taizo,Shimizu, Yo,Hegmann, Torsten
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p. 1180 - 1192
(2015/03/04)
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- A convenient one-step reaction leading to a key discotic intermediate: Mono-hydroxy-triphenylene at multi-gram scale
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This work reveals a novel reaction route deviated from a Scholl coupling reaction with an interrogation into the mechanism. A catalytic function of FeCl3 in the presence of protons plays a key role in the new reaction. It was discovered that by increasing the quantity of reagent FeCl3 is able to shift the reaction product from a symmetrically hexa-substituted coupling one to a mono-hydrolysed coupling product. The discovery offers a chance to explore and understand the reaction mechanism further. The new reaction enables a convenient one-step synthesis of mono-hydroxy-penta-alkoxytriphenylene, a key discotic liquid crystal intermediate for organic electronic materials, from a simple 1,2-dialkoxybenzenes reactant at a yield up to 65%.
- Xiao, Weikang,He, Zhiqun,Xu, Min,Wu, Nan,Kong, Xiangfei,Jing, Xiping
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p. 700 - 705
(2015/01/30)
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- Method of manufacturing tripenylene compd.
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PROBLEM TO BE SOLVED: To provide a method for producing a 2,3,6,7,10,11-hexasubstituted triphenylene compound in a high yield which enables mass production at a low cost and on an industrial scale and reduces the load to the environment as much as possible. SOLUTION: The method for producing a 2,3,6,7,10,11-hexasubstituted triphenylene compound by the trimerization reaction of a 1,2-disubstituted benzene compound in the presence of a compound including a divalent or trivalent iron ion comprises using at least one reaction solvent selected from the group consisting of carboxylic acid esters, lactones, carbonic acid esters, and sulfurous esters in the reaction. COPYRIGHT: (C)2013,JPOandINPIT
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Paragraph 0086; 0087; 0095
(2016/10/09)
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- Synthesis and mesomorphism of asymmetric triphenylene discotic liquid crystals bearing with mono-amido-based alkyl soft chains
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A series of triphenylene discotic liquid crystals with amido-based alkyl chains in different lengths were synthesized and characterized. The liquid crystal properties were studied with differential scanning calorimetry and polarizing optical microscopy. The influences of amide alkyl chain lengths on the mesomorphism were discussed. Based on the results, we concluded that the triphenylene discogens with an amido-based alkyl chain could form intermolecular hydrogen bonds inside their columnar stacks, and hence, exhibit higher melting and clearing points, and wider mesophase ranges. Copyright Taylor & Francis Group, LLC.
- Zhao,Guo,Yu,Wang,Hu,Wang,Monobe,Shimizu
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scheme or table
p. 37 - 47
(2012/01/13)
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- Click chemistry applied in the synthesis of symmetrical triphenylene-based discotic liquid-crystalline dimers
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Symmetrical triphenylene dimers connected by a bis-triazole moiety have been synthesized and characterized. The bis-triazole part is formed as final step utilizing a straightforward double click reaction (CuAAC) allowing further structural variations of the linker. The 1,3-bis(triazol-1-yl) propyltriphenylene-based dimer display columnar mesophase over a wide range of temperatures starting at ambient temperature. Georg Thieme Verlag Stuttgart. New York.
- Thevenet, Damien,Neier, Reinhard
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p. 3801 - 3806
(2012/01/06)
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- Improved synthesis of monohydroxytriphenylenes (MHTs) - Important precursors to discotic liquid crystal families
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Monohydroxypentaalkoxytriphenylenes are important intermediates for elaboration into complex covalently linked discotic liquid crystal assemblies. An improved, simple synthetic protocol is described that gives rapid access to these precursors in a single step.
- Kong, Xiangfei,He, Zhiqun,Gopee, Hemant,Jing, Xiping,Cammidge, Andrew N.
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experimental part
p. 77 - 79
(2011/02/25)
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- Hexaalkoxytriphenylenes synthesized from facile solvent-free oxidative coupling trimerization
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By grinding 1,2-dialkoxybenzene with anhydrous FeCl3 powder using a glass pestle in a mortar at ambient temperature under solvent-free conditions, hexaalkoxytriphenylenes were obtained in good yield (up to 90%) in 30min. The solvent-free oxidative coupling reaction is a facile, efficient, green-chemistry method.
- Bai, Weibin,Lin, Jinhuo
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experimental part
p. 903 - 906
(2011/04/23)
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- An efficient photoinduced deprotection of aromatic acetals and ketals
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A novel type of photodeprotection reaction of simple aromatic acetals and ketals is described. The deprotection is highly efficient under optimized conditions. The aromatic ring confers the photoreactivity to the compounds. The efficiency of the process depends on the structure of the acetal moiety. The common minor side reaction, the photooxidation, becomes the major reaction pathway in the cases of cyclic acetals. The use of photon as only reagent makes this procedure especially attractive for acetal deprotection.
- Thevenet, Damien,Neier, Reinhard
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body text
p. 331 - 346
(2011/04/22)
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- Novel triphenylenoimidazole discotic liquid crystals
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A novel discotic core was constructed by fusing imidazole unit with well-known triphenylene discotic core. Two new imidazole fused unsymmetrically substituted triphenylene derivatives were prepared and characterized. While the molecular structures of the new compounds were verified by 1H NMR, UV, MS and elemental analysis, their liquid crystalline properties were determined by polarizing optical microscopy, differential scanning calorimetry and X-ray diffraction studies. These triphenylenoimidazole derivatives were found to exhibit hexagonal columnar mesomorphism over a wide temperature range.
- Kumar, Sandeep,Gupta, Satyam Kumar
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scheme or table
p. 5363 - 5367
(2011/10/30)
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- New discotic mesogens based on triphenylene-fused triazatruxenes: Synthesis, physical properties, and self-assembly
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A new type of discotic mesogen based on triphenylene-fused triazatruxenes was prepared by microwave-assisted 6-fold Suzuki coupling reactions from hexabromotriazatruxene, followed by FeCl3-mediated oxidative cyclodehydrogenation. These disklike molecules showed extended π-conjugation, compared with the triphenylene and triazatruxene themselves. More importantly, they possess desirable HOMO energy levels, which allow efficient charge injection from electrodes such as gold electrodes. Their thermal behavior and self-assembly were studied by different techniques such as thermogravimetric analysis, differential scanning calorimetry, polarizing optical microscopy, and variable-temperature X-ray diffraction. These new discotic mesogens have very good thermal stability and show thermotropic liquid crystalline behavior. Ordered columnar liquid crystalline phase and crystalline phase were observed in both compounds with tunable phase transition temperatures and mesophase widths. The charge carrier mobilities of these extended triazatruxene samples were determined using the space-charge limited-current (SCLC) technique and high hole mobilities of 0.03 and 0.8 cm2 V-1 s-1) were obtained for TP-TATC6 and TP-TATC12, respectively. Interestingly, the long-aliphatic-chain-substituted TP-TATC12 can gelate several nonpolar hydrocarbon solvents or polar aliphatic alcohol and ester solvents, because of strong intermolecular interactions. All these properties qualify this new type of discotic liquid crystals as potential hole transporting materials for electronic devices such as field-effect transistors, light-emitting diodes, and solar cells.
- Zhao, Baomin,Liu, Bo,Png, Rui Qi,Zhang, Kai,Lim, Kheng Aik,Luo, Jing,Shao, Jinjun,Ho, Peter K.H.,Chi, Chunyan,Wu, Jishan
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p. 435 - 449
(2011/10/09)
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- Synthesis and characterisation of novel hexaalkoxytriphenylenes bearing an additional alkyl chain in the α-position
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Exhaustive alkylation of hexahydroxytriphenylene results in production of significant quantities of a side product bearing one additional alkyl chain originating from C-alkylation. A series of these novel materials have been isolated and characterised to
- Cammidge, Andrew N.,Gopee, Hemant,Patel, Hitesh
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experimental part
p. 3513 - 3515
(2009/10/26)
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- The first examples of discotic radicals: Columnar mesomorphism in spin-carrying triphenylenes
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The synthesis, columnar behaviour and magnetic properties of the first examples of radical discotics are reported. These organic molecular systems with spin sources have been accomplished by covalently linking triphenylene with molecular radicals. The col
- Yelamaggad, Channabasaveshwar V.,Achalkumar, Ammathnadu S.,Rao, D. S. Shankar,Nobusawa, Mitsunori,Akutsu, Hiroki,Yamada, Jun-Ichi,Nakatsuji, Shin'Ichi
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supporting information; experimental part
p. 3433 - 3437
(2010/02/28)
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- Ambipolar charge carrier transport properties in the homologous series of 2,3,6,7,10,11-hexaalkoxytriphenylene
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In this study, ambipolar charge carrier transport properties were investigated for a homologous series of triphenylene by time-of-flight (TOF) technique for the homeotropic domains. Ambipolar electronic charge carrier transport was observed and the both positive and negative charge carrier mobilities decrease with the increase of the alkyl chain length. Ionic conduction was also observed for the negative charge carrier transport except for C4OTP and any remarkable dependency of the alkyl chain length was not seen. It was reasonably found that both the positive and negative charged carrier mobilities by electronic hopping process is affected by the intra columnar order.
- Monobe, Hirosato,Shimizu, Yo,Okamoto, Shuichi,Enomoto, Hiroyuki
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- A convenient and economic method for the synthesis of monohydroxy- pentaalkoxy- and hexaalkoxytriphenylene discotics
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A one-step process for the preparation of mono-functionalized triphenylene discotics is presented. Oxidative trimerization of ortho-dialkoxybenzenes using FeCl3 in nitromethane and a catalytic amount of various acids, furnished monohydroxy-pentaalkoxytriphenylene in addition to hexaalkoxytriphenylene. These products can be easily separated by column chromatography over aluminium oxide.
- Kumar, Sandeep,Lakshmi
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p. 2603 - 2605
(2007/10/03)
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- Intermolecular organisation of triphenylene-based discotic mesogens by interdigitation of alkyl chains
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Two series of hexakis(alkyloxy)triphenylenes have been synthesised and characterised. All materials contain two different lengths of n-alkyloxy chains. Series I (CmCn) materials contain three -OC5H11 chains and three -OCnH2n+1 chains. Series II (CmCn) materials contain three -OCmH2m+1 chains and three -OCnH2n+1 chains, such that m+n = 10. Hexagonal columnar mesophases are observed in Series I for n≥3 and, in Series II, for C5C5 and C6C4. Investigation by XRD shows that, within Series I, increasing the Cn chain length increases the intercolumnar spacing. Furthermore, the intercolumnar spacings for constitutional isomers are identical. The difference in the lengths of the two types of alkyl chain at the periphery of the molecules is defined as the Interdigitation Length (IL) and is a measure of the maximum extent of interdigitation that is possible between neighbouring molecules. Series I and II materials have been studied to probe the effect of IL on the change in enthalpy (ΔHCol-1) and entropy (ΔSCol-1) for the mesophase to isotropic liquid phase transition. In contrast to CxCx materials, which show a decrease in ΔHCol-1 and ΔSCol-1 with increasing chain length, Series I and II mesogens all exhibit ΔHCol-1 and ΔSCol-1 values similar to those of long chain CxCx materials, irrespective of chain length.
- Allen,Diele,Harris,Hegmann,Kariuki,Lose,Preece,Tschierske
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p. 302 - 311
(2007/10/03)
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- Synthesis and investigation of polysubstituted triphenylenes with a predictable type of mesomorphism
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This paper reports on synthesis and investigation of columnar mesophases of the new members of the homologous series of nitro and amino derivatives of hexaalkoxytriphenylenes, whose mesomorphism was predicted earlier. The forecast is in good agreement with the experimental data. The effect of the introduction of the donor and acceptor groups into the central fragment of triphenylene on the phase transition temperature, texture, and range of existence of columnar mesophases is examined. The predicting ability of the molecular parameters suggested previously for the series under analysis is discussed. It is found that introduction of a nitro group, which is a strong electron acceptor, into the central fragment of triphenylene lowers the melting temperature of the compound versus its analog and does not promote columnar mesomorphism in the lower nonmesomorphous homologs. At the same time, this slightly expands the range of existence of the mesophase in higher homologs.
- Zemtsova,Syromyatnikova,Kotovich,Akopova
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- Synthesis of hexa-alkyloxytriphenylenes using FeCl3 supported on alumina
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Several symmetrical and unsymmetrical hexa-alkyloxytriphenylenes have been synthesised in good yield from diakyloxy benzenes and terphenyl derivatives using FeCl3 supported on alumina.
- Cooke, Graeme,Sage, Valerie,Richomme, Tanguy
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p. 1767 - 1771
(2007/10/03)
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- Oxidative trimerization of o-dialkoxybenzenes to hexaalkoxytriphenylenes: Molybdenum(v) chloride as a novel reagent
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Symmetrically substituted hexaalkoxytriphenylenes are obtained from o-dialkoxybenzenes by oxidative trimerization with MoCl5 in high yields; oxidative coupling of a 3,3′,4,4′-tetraalkoxybiphenyl and 1,2-dialkoxybenzenes yields unsymmetrically substituted derivatives of triphenylene and a direct coupling of a 3,3′,4,4′-tetraalkoxybiphenyl with alkoxyphenol produces the monofunctionalized triphenylenes.
- Kumar, Sandeep,Manickam
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p. 1615 - 1616
(2007/10/03)
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- A Quick-and-Easy Route to Unsymmetrically Substituted Derivatives of Triphenylene: Preparation of Polymeric Discotic Liquid Crystals
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Unsymmetrically substituted triphenylenes can be obtained by the iron(III) chloride mediated oxidative coupling of a 3,3',4,4'-tetraalkoxybiphenyl with a 1,2-dialkoxybenzene thus opening up a practicable route to polymeric discotic liquid crystals.
- Boden, Neville,Bushby, Richard J.,Cammidge, Andrew N.
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p. 465 - 466
(2007/10/02)
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- CHARGE TRANSFER SALTS OF HIGHLY ORIENTED FIBERS OF DISCOTIC LIQUID CRYSTAL HET-n
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The charge transfer salt of highly oriented fibers of discotic liquid crystals of 2,3,6,7,10,11-hexa-alkoxytriphenylene (HET-n) and 2,3,6,7,10,11-hexa-alkanoyloxytriphenylene (HAT-n) can be made by a strand technique followed by a doping process.As a result, the bromide doped HET-5 fiber shows a conductivity of three orders of magnitude higher than that of the bromine doped HET-5 powder.
- Chiang, Long Y.,Stokes, James P.,Safinya, Cyrus R.,Bloch, Aaron N.
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p. 279 - 288
(2007/10/02)
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- DISSYMMETRIC HEXASUBSTITUTED TRIPHENYLENES.
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Several dissymmetrical hexasubstituted triphenylenes were prepared exhibiting a low temperature thermotropic mesophase. It is shown that it corresponds to a columnar mesophase (an hexagonal arrangement of columns of discs). The magnetic properties of these new disc-like liquid crystals are compared with those of the corresponding symmetrical ones.
- Nguyen Huu Tinh,Bernaud,Sigaud,Destrade
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p. 307 - 314
(2007/10/02)
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