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Synthesis and mesomorphic properties of "side-on" hybrid liquid crystalline silsesquioxanes. SOFT MATTER 2023; 19:9115-9122. [PMID: 37990586 DOI: 10.1039/d3sm00801k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
Novel hybrid silsesquioxane-based liquid crystalline derivatives with varied lengths of spacers and tails have been synthesized by hydrosilylation reactions of octakis(dimethylsiloxy)silsesquioxane and side-on mesogens via a platinum catalyst. The thermal behavior of three types of silsesquioxane-based liquid crystals (LCs), differentiated by the molecular structure of mesogens, was investigated by differential scanning calorimetry (DSC) and polarising optical microscopy (POM). Temperature-dependent small and wide-angle X-ray scattering was used to verify liquid crystalline phases, revealing that the silsesquioxane-based derivatives formed hexagonal columnar and nematic mesophases, and the effect of the molecular structure of the mesogens and the spacer length on the formation of LC phases is discussed. This investigation demonstrated that the choice of the "side-on" attachments plays a crucial role in enhancing the emergence of the nematic phase.
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Ordered structure constructed from C2-symmetric hexa- peri-hexabenzocoronene linked with oligo(dimethylsiloxane). SOFT MATTER 2022; 18:3430-3436. [PMID: 35437558 DOI: 10.1039/d2sm00059h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The preparation of sub-5-nm ordered structures is very important to the development of today's nanotechnology. Block molecules have the potential to form structures with significantly small characteristic dimensions. Herein two novel organic-inorganic block molecules composed of a hexa-peri-hexabenzocoronene (HBC) core and two oligo(dimethylsiloxane) (ODMS) tails with C2 symmetry are reported. A hierarchical lamello-columnar structure with a two-dimensional rectangular lattice where HBC cores adopt a tilted arrangement was obtained from their bulk self-assembly. The feature sizes are all below 5 nm and can be regulated via the number of ODMS chains. Sub-5-nm line structures were obtained through spin-coating of the block molecules onto silicon substrates modified with poly(dimethylsiloxane). As organic-inorganic hybrid materials, these block molecules may be further applied in sub-5-nm nanopatterning.
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Electro-oxidative Trimerization of 1,2-Dimethoxybenzene: Reductive Workup Strategy and Alternating Current Electrolysis to Peel off the Precipitated Radical Cation Ion Pair. CHEM LETT 2022. [DOI: 10.1246/cl.220112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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4
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Mesomorphic properties of linear and branched new triphenylene‐based poly(ester‐ether)s. JOURNAL OF POLYMER SCIENCE 2020. [DOI: 10.1002/pol.20190106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Selective Hydrogenation of Phenylacetylene on a Pd-Containing Catalyst Based on a Polymer Layered Substrate. RUSS J APPL CHEM+ 2020. [DOI: 10.1134/s1070427220020159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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6
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Lyotropic liquid crystalline hexagonal mesophase. Thermo-morphologic and magneto-morphologic transformations, electrical conductivity and optical refractive properties: Effect of optically active compounds. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2019.112175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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7
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Highly efficient synthesis of C3-symmetric O-alkyl substituted triphenylenes and related Mannich derivatives. Org Chem Front 2018. [DOI: 10.1039/c8qo00414e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
C3-Symmetric tris-benzyl-O-substituted hexahydroxytriphenylene (HHTP) was prepared through selective ring opening with DIBAL-H in 48% yield (38% from HHTP in a two-step synthesis).
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Synthesis and characterization of new H-shaped triphenylene discotic room-temperature liquid crystal tetramers by a copper-free click reaction. NEW J CHEM 2018. [DOI: 10.1039/c7nj02695a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of new H-shaped triphenylene discotic liquid crystal tetramers has been designed and synthesized using a copper-free [3+2] cycloaddition reaction.
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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. J Phys Chem B 2017; 121:8593-8602. [PMID: 28817282 DOI: 10.1021/acs.jpcb.7b06737] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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.
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Synthesis and liquid crystalline studies of disc-shaped molecule on azo-bridged benzothiazole-phenyl ethers. J Mol Liq 2016. [DOI: 10.1016/j.molliq.2016.08.110] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Topological Control of Columnar Stacking Made of Liquid-Crystalline Thiophene-Fused Metallonaphthalocyanines. Chemistry 2016; 5:150-6. [PMID: 27308226 PMCID: PMC4906472 DOI: 10.1002/open.201500205] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Indexed: 11/07/2022]
Abstract
The spontaneous organization of two-dimensional polyaromatic molecules into well-defined nanostructures through noncovalent interactions is important in the development of organic-based electronic and optoelectronic devices. Two regioisomers of thiophene-fused zinc naphthalocyanines ZnTNcendo and ZnTNcexo have been designed and synthesized to obtain photo- and electroactive liquid crystalline materials. Both compounds exhibited liquid crystalline behavior over a wide temperature range through intermolecular π-π interactions and local phase segregation between the aromatic cores and peripheral side chains. The structural differences between ZnTNcendo and ZnTNcexo affected the stacking mode in self-assembled columns, as well as symmetry of the two-dimensional rectangular columnar lattice. The columnar structure in liquid crystalline phase exhibited an ambipolar charge-transport behavior.
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Hierarchical superstructures from a star-shaped molecule consisting of a cyclic oligosiloxane with cyanobiphenyl moieties. SOFT MATTER 2015; 11:58-68. [PMID: 25407404 DOI: 10.1039/c4sm02239d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Unconventional star-shaped liquid crystals (abbreviated as SiLCs) were successfully synthesized by chemically connecting four cyanobiphenyl anisotropic mesogens to the periphery of a super-hydrophobic and ultra-flexible cyclic tetramethyltetrasiloxane ring with flexible hexyl chains. Based on the combined experimental techniques of differential scanning calorimetry (DSC), cross-polarized optical microscopy (POM), solid-state carbon-13 ((13)C) nuclear magnetic resonance (NMR) spectroscopy and one-dimensional (1D) wide-angle X-ray diffraction (WAXD), it was found that the SiLC molecule exhibited the monotropic phase transition from a LC phase to a crystalline phase. The crystalline phase was only detected during slow heating processes above its glass transition temperature, while a LC phase was formed both during cooling and during heating processes. The hierarchical superstructures were identified from the structure-sensitive 2D WAXD of the macroscopically oriented SiLC film and confirmed by selected area electron diffraction (SAED) of the SiLC single crystals. The molecular packing symmetry in the monoclinic unit cell was further investigated by computer simulations on the real and reciprocal spaces. Macroscopically oriented SiLC hierarchical superstructures on the different length scales may provide the targeted physical properties, which can allow us to apply SiLC molecules in the fields of electro-optical devices and nonlinear optics.
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Entwicklung struktureller Komplexität durch Selbstorganisation in flüssigkristallinen Systemen. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201300872] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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15
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Development of structural complexity by liquid-crystal self-assembly. Angew Chem Int Ed Engl 2013; 52:8828-78. [PMID: 23934786 DOI: 10.1002/anie.201300872] [Citation(s) in RCA: 349] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Indexed: 11/09/2022]
Abstract
Since the discovery of the liquid-crystalline state of matter 125 years ago, this field has developed into a scientific area with many facets. This Review presents recent developments in the molecular design and self-assembly of liquid crystals. The focus is on new exciting soft-matter structures distinct from the usually observed nematic, smectic, and columnar phases. These new structures have enhanced complexity, including multicompartment and cellular structures, periodic and quasiperiodic arrays of spheres, and new emergent properties, such as ferroelctricity and spontaneous achiral symmetry-breaking. Comparisons are made with developments in related fields, such as self-assembled monolayers, multiblock copolymers, and nanoparticle arrays. Measures of structural complexity used herein are the size of the lattice, the number of distinct compartments, the dimensionality, and the logic depth of the resulting supramolecular structures.
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A new methanol solvate and Hirshfeld analysis of π-stacking in 2,3,6,7,10,11-hexahydroxytriphenylene solvates. Acta Crystallogr C 2013; 69:251-4. [DOI: 10.1107/s0108270113001893] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 01/18/2013] [Indexed: 11/10/2022] Open
Abstract
The structure of 2,3,6,7,10,11-hexahydroxytriphenylene (hhtp) methanol monosolvate, C18H12O6·CH3OH, has triclinic symmetry (space groupP\overline{1}). The compound has a three-dimensional layered network structure formed by intermolecular hydrogen bonding. Structure analysis with Hirshfeld surfaces is shown to be a sensitive method for comparing π-stacking effects in the five known solvates of hhtp. The title structure shows slightly weaker π-stacking than the dihydrate, but stronger π-stacking than the other three solvates.
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2,3,6,7,10,11-Hexamethoxytriphenylene (HMTP): A new organic cathode material for lithium batteries. Electrochem commun 2012. [DOI: 10.1016/j.elecom.2012.05.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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2,3,6,7,10,11-Hexahydroxytriphenylene tetrahydrate: a new form of an important starting material for supramolecular chemistry and covalent organic frameworks. Acta Crystallogr C 2011; 67:o143-5. [DOI: 10.1107/s0108270111002988] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 01/22/2011] [Indexed: 11/10/2022] Open
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Abstract
We show that discotic mesogens can be used to lower the activation energy barrier for proton transport.
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Polyphosphorylated triphenylenes: synthesis, crystal structure, and selective catechol recognition. J Org Chem 2009; 74:652-9. [PMID: 19049263 DOI: 10.1021/jo802015k] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Designed as a multivalent hydrogen bond acceptor, new receptors, Discopus 1a,b, were built from a triphenylene core surrounded by six (diaryl)phosphinate groups. An efficient synthesis was developed to prepare these elaborated structures in a high overall yield. The X-ray structure of receptor 1b showed strong cooperative hydrogen bonds with two water molecules and intermolecular CH-pi contacts. In chloroform, Discopus 1a,b displayed recognition properties toward dihydroxybenzenes, selectively forming complexes with catechol derivatives 4a-c in a 1:2 (host:guest) stoichiometry. According to NMR and microcalorimetry titrations, association constants were found in the 30-2837 M(-1) range, which were larger than those reported for curvated catechol receptors (14-120 M(-1)). Interestingly, Discopus present two distinct catechol binding sites. Weak hydrogen bonding between host phosphinates and guest hydroxyl groups was shown by infrared spectroscopy and (31)P NMR. Molecular dynamics simulations and recognition experiments suggested that a stronger hydrogen bond assisted by a pi-interaction between the Discopus core and one catechol molecule could exist within the 1:2 complex.
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Local lamellar organisation of discotic mesogens carrying fluorinated tails. ACTA ACUST UNITED AC 2007. [DOI: 10.1039/b707880c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Organised structures of flexible bolaamphiphiles with trisiloxane spacers: three- and two-dimensional molecular assemblies with different molecular conformation. SOFT MATTER 2006; 2:157-165. [PMID: 32646142 DOI: 10.1039/b516768j] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We designed and synthesised new bolaamphiphiles consisting of hydrophobic rigid cores, flexible trisiloxane spacers, and terminal ammonium groups. Organised structures of the bolaamphiphiles with biphenyl and azobenzene cores were examined in the bulk and in the monolayer states. In the bulk states, these molecules exhibited layered liquid crystal phases with an extended molecular conformation. The biphenyl derivative showed only lyotropic liquid crystallinity in the presence of water. In contrast, the azobenzene derivative exhibited both thermotropic and lyotropic liquid crystal behaviour. UV-vis spectroscopy for the materials indicated that the association of the azobenzene cores contributed to the formation of the stable mesomorphic structures. On the other hand, when these molecules were spread on the water surface, monolayer films were formed with both hydrophilic ends on the water surface. The compression of the monolayer films induced the conformational changes in the bolaamphiphiles from a flat-lying extended state to a reverse U-shaped folded state and the core parts were lifted up to the uppermost film surface, maintaining their flat orientation. The cores integrated to the film surface were shown to be monomeric species by UV-vis spectroscopy, whereas the azobenzene cores tend to associate in the bulk and on the water surface at low surface pressures. The - photoisomerisation and - thermal isomerisation of the azobenzene cores occurred efficiently in the compressed monolayer films, which is available to tune the surface properties of the monolayer films. For these monolayer films with two-dimensional core arrays, we can expect novel surface-mediated functionalities as photo- and electro-active surfaces, alignment layers for materials synthesis, and molecular sensors due to their tunabilities in core density and polarity.
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Abstract
New fan-shaped ionic liquids forming columnar liquid crystalline phases have been prepared to obtain one-dimensional ion-transporting materials. The ionic liquids consist of two incompatible parts: an imidazolium-based ionic part as an ion-conducting part and tris(alkyloxy)phenyl parts as insulating parts. Two compounds having octyl and dodecyl chains have been synthesized. Self-assembly of these materials leads to the formation of thermotropic hexagonal columnar liquid crystalline states at room temperature. Anisotropic one-dimensional ionic conductivities have been successfully measured by the cells having comb-shaped gold electrodes. The self-organized columns have been aligned macroscopically in two directions by shearing perpendicular and parallel to the electrodes. The ionic conductivities parallel to the column axis are higher than those perpendicular to the axis. The incorporation of lithium salts in these columnar materials leads to the enhancement of the ionic conductivities and their anisotropy. These materials would be useful for anisotropic transportation of ions at the nanometer level.
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Calamitic bolaamphiphiles with (semi)perfluorinated lateral chains: polyphilic block molecules with new liquid crystalline phase structures. J Am Chem Soc 2003; 125:10977-96. [PMID: 12952480 DOI: 10.1021/ja036213g] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Novel bolaamphiphiles consisting of a rigid biphenyl unit, two terminal polar 1,2-diol units and laterally attached (semi)perfluorinated chains have been synthesized via palladium-catalyzed cross coupling reactions as the key step. The thermotropic liquid crystalline behavior of these compounds was investigated by polarized light optical microscopy, DSC, and X-ray scattering, and the influences of the length, number, structure, and position of the lateral chain on the mesomorphic properties were studied. A wide variety of unique liquid crystalline phases were found upon elongation of the lateral semiperfluorinated chains. For short- and medium-chain length a series of columnar phases were observed, and upon further elongation of the lateral chain a series of novel mesophases with layer structures were found. In the columnar phases, the nonpolar lateral chains segregate into columns, which are embedded in honeycomb-like networks of cylinders consisting of the biphenyl units. Strings of hydrogen-bonding networks of the diol groups provide cohesive forces, which maintain the overall structure. Changing the length of the lateral chains influences the diameter of the columns and thus determines the number of biphenyl units which are required to surround these columns. The number of these units [four (c2mm, p4mm), five (p2gg), six (p6mm), eight (c2mm) or 10 (p2gg)] defines the shape of the cylinders as well as the lattice type of the columnar phase. It is proposed that the columnar phases with a p2gg lattice result from the regular organization of pairs of cylinders which have a pentagonal cross sectional shape. In the mesophases with layer structure the aromatic rodlike cores are arranged parallel to the layer planes, and the onset of orientational and positional ordering of the biphenyl segments leads to a sequence of subtypes for these lamellar phases (Lam(Iso)-Lam(N)-Lam(X)).
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