Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• resulted from optically active constituents. Compound 53, due to its elongated rigid structure, holds potential for use as a chiral dopant in nematic liquid crystals (LCs); however, the helical twisting powers of 53 within nematic LCs are limited. Recently, Alonso-Gómez et al. reported the synthesis and

A new family of four-ring bent-core nematic liquid crystals with highly polar transverse and end groups

• Kalpana Upadhyaya,
• Venkatesh Gude,
• Golam Mohiuddin and
• Rao V. S. Nandiraju

Beilstein J. Org. Chem. 2013, 9, 26–35, doi:10.3762/bjoc.9.4

Perhydroazulene-based liquid-crystalline materials with smectic phases

• Zakir Hussain,
• Henning Hopf and
• S. Holger Eichhorn

Beilstein J. Org. Chem. 2012, 8, 403–410, doi:10.3762/bjoc.8.44

• orientational order, have found little commercially successful applications. So far, an enormous amount of experimental and theoretical work exists in the literature concerning the nematic liquid crystals [1][2][3][4][5][6][7][8], whereas smectic liquid crystals have not been studied to the same extent

Synthesis and mesomorphic properties of calamitic malonates and cyanoacetates tethered to 4-cyanobiphenyls

• Katharina C. Kress,
• Martin Kaller,
• Kirill V. Axenov,
• Stefan Tussetschläger and
• Sabine Laschat

Beilstein J. Org. Chem. 2012, 8, 371–378, doi:10.3762/bjoc.8.40

• differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction (WAXS). Keywords: cyanoacetates; 4-cyanobiphenyls; liquid crystals; malonates; nematic; Introduction Nematic liquid crystals display mesophases in which the molecules are oriented along one vector defined by the director

• axis, but with the molecular arrangement in random positional order [1]. Nematic phases typically display low viscosity [2][3][4]. Due to the long-range orientational order they reveal anisotropic properties. These features make nematic liquid crystals very attractive materials for electronics [5][6][7

• ][8], for the construction of liquid crystal displays [9][10][11], or as anisotropic conductors [12][13]. Over the past few decades, a huge variety of organic calamitic compounds, which form nematic liquid crystals, have been synthesized and investigated [1][14]. Bulkin et al. were the first to

The interplay of configuration and conformation in helical perylenequinones: Insights from chirality induction in liquid crystals and calculations

• Elisa Frezza,
• Silvia Pieraccini,
• Stefania Mazzini,
• Alberta Ferrarini and
• Gian Piero Spada

Beilstein J. Org. Chem. 2012, 8, 155–163, doi:10.3762/bjoc.8.16

• essentially determined by the axial chirality (helicity) of the core of the perylenequinones. Keywords: chirality; conformational analysis; DFT calculations; helical twisting power; nematic liquid crystals; Introduction The phenomenon of chiral induction in nematic mesophases has been known for a long time

The preparation of 3-substituted-1,5-dibromopentanes as precursors to heteracyclohexanes

• Bryan Ringstrand,
• Martin Oltmanns,
• Jeffrey A. Batt,
• Aleksandra Jankowiak,
• Richard P. Denicola and
• Piotr Kaszynski

Beilstein J. Org. Chem. 2011, 7, 386–393, doi:10.3762/bjoc.7.49

• the development of polar, zwitterionic nematic liquid crystals having large longitudinal dipole moments for formulation of nematic materials with positive dielectric anisotropy [24][25]. The zwitterions consist of six-membered sulfonium rings attached to a boron cluster, either [closo-1-CB9H10]− or

Symmetry breaking and structure of a mixture of nematic liquid crystals and anisotropic nanoparticles

• Marjan Krasna,
• Matej Cvetko and
• Milan Ambrožič

Beilstein J. Org. Chem. 2010, 6, No. 74, doi:10.3762/bjoc.6.74

• spatially homogeneous structure is gradually attained. However, if impurities are present, they can pin the defects [12][13][14]. Consequently, the domain structure can be stabilized. In this contribution we study numerically a mixture of uniaxial nematic liquid crystals and rod-like NPs using a Lebwohl

• degree of biaxiality. Conclusion We studied numerically structural characteristics of a diluted mixture of nematic liquid crystals and ferromagnetic nanoparticles. The concentration x of NPs is low enough in order to avoid a phase separation process [29]. We consider cases where both LC molecules and NPs

Competition between local disordering and global ordering fields in nematic liquid crystals

• Matej Cvetko,
• Milan Ambrožič and
• Samo Kralj

Beilstein J. Org. Chem. 2010, 6, No. 2, doi:10.3762/bjoc.6.2

• Department, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia 10.3762/bjoc.6.2 Abstract We study the influence of external electric or magnetic field B on orientational ordering of nematic liquid crystals or of other rod-like objects (e.g. nanotubes immersed in a liquid) in the presence of random

• ). Conclusions We have studied the influence of external ordering electric or magnetic field B on systems of rod-like objects (e.g. nematic liquid crystals or a dispersion of nano-rods in a liquid environment [20][21]) in the presence of random anisotropic type of disorder. We express the interaction energy F of

Low temperature enantiotropic nematic phases from V-shaped, shape-persistent molecules

• Matthias Lehmann and
• Jens Seltmann

Beilstein J. Org. Chem. 2009, 5, No. 73, doi:10.3762/bjoc.5.73

• engineering; thiadiazoles; V-shaped mesogens; Introduction Most molecules forming nematic liquid crystals, the nematogens, are based on rod-shaped (calamitic), anisometric cores with peripheral flexible chains along the molecular long axis [1]. Nematic phases are the simplest liquid crystalline mesophases

• of a series of thiadiazoles of general structure II is presented and the successful approach to low temperature, enantiotropic nematic liquid crystals in the family of bent-shaped oligo(phenylene ethynylenes) will be discussed. Results and Discussion Synthesis The shape-persistent arms of the new

Chiral amplification in a cyanobiphenyl nematic liquid crystal doped with helicene-like derivatives

• Alberta Ferrarini,
• Silvia Pieraccini,
• Stefano Masiero and
• Gian Piero Spada

Beilstein J. Org. Chem. 2009, 5, No. 50, doi:10.3762/bjoc.5.50

• ; helicene; nematic liquid crystal; Surface Chirality model; Introduction Nematic liquid crystals (LCs) are fluid phases formed by anisometric molecules which, though free to rotate as in ordinary liquids, are preferentially aligned along a common axis, called director. The addition of a chiral non-racemic