The use of isoxazoline and isoxazole scaffolding in the design of novel thiourea and amide liquid-crystalline compounds

• Itamar L. Gonçalves,
• Rafaela R. da Rosa,
• Vera L. Eifler-Lima and
• Aloir A. Merlo

Beilstein J. Org. Chem. 2020, 16, 175–184, doi:10.3762/bjoc.16.20

• range than the isoxazoline derivatives. Optical textures observed on POM for thioureas 17a (a), 17b (b), 18a (c), 18b (d) and 18c (e,f). All images were obtained upon cooling from the isotropic phase with the exception of (b). The “grid aspect” found in images (c) and (f) is an artifact due to the fast

• movement of the fluid mesophase. Optical textures observed on POM of amide 19. (a) Fan-shaped focal conic texture of the SmA mesophase upon cooling at 201 °C; (b) and (c) broken fan-shaped focal conic and schlieren textures of the SmC mesophase upon cooling at 198 °C. DSC curves for the thiourea 17a (A

Novel biphenyl-substituted 1,2,4-oxadiazole ferroelectric liquid crystals: synthesis and characterization

• Mahabaleshwara Subrao,
• Dakshina Murthy Potukuchi,
• Girish Sharada Ramachandra,
• Poornima Bhagavath,
• Sangeetha G. Bhat and
• Srinivasulu Maddasani

Beilstein J. Org. Chem. 2015, 11, 233–241, doi:10.3762/bjoc.11.26

• ) polarization switching. The mesomorphic thermal stabilities of these compounds are discussed in the domain of the symmetry and the flexibility of the alkyloxy end chain length attached to the chiral center. Keywords: 3,5-disubstituted-1,2,4-oxadiazoles; ferroelectric switching; mesomorphism; optical textures

The influence of intraannular templates on the liquid crystallinity of shape-persistent macrocycles

• Joscha Vollmeyer,
• Ute Baumeister and
• Sigurd Höger

Beilstein J. Org. Chem. 2014, 10, 910–920, doi:10.3762/bjoc.10.89

• kind of a nematic phase, in agreement with the optical textures. Obviously, similar clusters as in the isotropic phase are observed in the nematic phase. No changes of the X-ray pattern indicating a phase transition could be detected on heating above or on cooling below 70 °C (see Figure S1 in

Triphenylene discotic liquid crystal trimers synthesized by Co₂(CO)₈-catalyzed terminal alkyne [2 + 2 + 2] cycloaddition

• Bin Han,
• Ping Hu,
• Bi-Qin Wang,
• Carl Redshaw and
• Ke-Qing Zhao

Beilstein J. Org. Chem. 2013, 9, 2852–2861, doi:10.3762/bjoc.9.321

• DSC traces are shown in Figure 3 and the phase transition data are summarized in Table 1. For the mesomorphism of the functionalized triphenylene monomers, compound 2 [52] and 3b [57] have been reported, 3a and 3c are new. They all display typical optical textures with homeotropic alignment behavior

Liquid-crystalline heterodimesogens and ABA-heterotrimesogens comprising a bent 3,5-diphenyl-1,2,4-oxadiazole central unit

• Govindaswamy Shanker,
• Marko Prehm and
• Carsten Tschierske

Beilstein J. Org. Chem. 2012, 8, 472–485, doi:10.3762/bjoc.8.54

• differential scanning calorimetry (DSC, DSC-7, Perkin-Elmer). The assignment of the mesophases is based on the combined results of optical textures and X-ray diffraction (XRD) studies. XRD investigations on aligned samples were performed by using a 2D wire detector (HI-Star, Siemens AG). Alignment was achieved

• Figure 8b) and is nonsplit and centered on the meridian for NcybA phases (Figure 3a). During investigation of compounds Thia-Ox/5 and CB-Ox/4 we found that there are also some differences in the optical textures of NcybC and NcybA phases. On cooling from the isotropic liquid state, the textures occur as

• of the optical textures of distinct types of 1,2,4-oxadiazole based dimesogens as observed between nontreated glass plates (Menzel cover glasses, Menzel GmbH, Braunschweig) between crossed polarizers: (a–d) compound Thia-Ox/5 at (a) T = 206 °C; (b) T = 197 °C; (c) T = 178 °C; (d) T = 173 °C NcybC-to

Liquid-crystalline nanoparticles: Hybrid design and mesophase structures

• Gareth L. Nealon,
• Romain Greget,
• Cristina Dominguez,
• Zsuzsanna T. Nagy,
• Daniel Guillon,
• Jean-Louis Gallani and
• Bertrand Donnio

Beilstein J. Org. Chem. 2012, 8, 349–370, doi:10.3762/bjoc.8.39

• directly with an equal mass of amino-functionalised mesogenic ligands 1 and 2 (Figure 3). Interestingly, highly anisotropic TiO2@1 hybrids several hundred nanometres in length and up to ~30 nm in width melted at 48 °C to give a series of optical textures up to 250 °C. X-ray analysis of the mesophase at 70

• Au@C6/13, whereas Au@C12/13 displayed evidence of 3-D long-range ordering. The structural model indicated that both Au@C12/13 and Au@C6/13 were comprised of NP columns, with the surrounding mesogens axially aligned in the column direction. Despite these results, however, the optical textures and

Improved syntheses of high hole mobility phthalocyanines: A case of steric assistance in the cyclo-oligomerisation of phthalonitriles

• Daniel J. Tate,
• Rémi Anémian,
• Richard J. Bushby,
• Suwat Nanan,
• Stuart L. Warriner and
• and Benjamin J. Whitaker

Beilstein J. Org. Chem. 2012, 8, 120–128, doi:10.3762/bjoc.8.14

• compound 7b the nature of the phase formed at temperatures below that for the Colh phase (the phase formed between 112 and 124 °C) remains uncertain, but comparison of the optical textures (compare Figure 2d with Figure 2b and Figure 2f) suggests that it is crystalline rather than liquid-crystalline, and

Ring-alkyl connecting group effect on mesogenic properties of p-carborane derivatives and their hydrocarbon analogues

• Aleksandra Jankowiak,
• Piotr Kaszynski,
• William R. Tilford,
• Kiminori Ohta,
• Adam Januszko,
• Takashi Nagamine and
• Yasuyuki Endo

Beilstein J. Org. Chem. 2009, 5, No. 83, doi:10.3762/bjoc.5.83

• [2.2.2]octane derivative 16C[6] is the only exception and exhibits a narrow range nematic phase above a soft crystalline phase designated as L or E on the basis of viscosity, ability to supercool, and optical textures. In general, bicyclo[2.2.2]octane derivatives 14C[6]–16C[6] exhibit orthogonal phases

• -carborane, A) and 1,10-dicarba-closo-decaborane (10-vertex p-carborane, B). Each vertex corresponds to a BH fragment and the sphere represents a carbon atom. The molecular structures of derivatives 1–20. Partial DSC trace for 16D[6]. Heating rate 5 K/min. Optical textures of 16D[6] obtained for the same

1-(4-Alkyloxybenzyl)-3-methyl-1H-imidazol-3-ium organic backbone: A versatile smectogenic moiety

• William Dobbs,
• Laurent Douce and
• Benoît Heinrich

Beilstein J. Org. Chem. 2009, 5, No. 62, doi:10.3762/bjoc.5.62

• molecules to form spontaneously a single homeotropic monodomain (Figure 5a) the nature of the mesophases could be quite easily assigned on the basis of their optical textures if separated microscope slides (100 μm spacer) were used. The utilization of a spacer allows the formation of large oriented

A convenient method for preparing rigid-core ionic liquid crystals

• Julien Fouchet,
• Laurent Douce,
• Benoît Heinrich,
• Richard Welter and
• Alain Louati

Beilstein J. Org. Chem. 2009, 5, No. 51, doi:10.3762/bjoc.5.51

• Br− > BF4− > PF6− > CF3SO3− (see Figure 5). The optical textures observed during slow cooling from isotropic melt showed the emergence of a smectic A phase (appearance of Batônnet rods, turning into a wide, fan-like, focal-conic texture). The smectic structure of the liquid crystal phase was