4,6-Diaryl-5,5-difluoro-1,3-dioxanes as chiral dopants for liquid crystal compositions

• Maurice Médebielle,
• Peer Kirsch,
• Jérémy Merad,
• Carolina von Essen,
• Clemens Kühn and
• Andreas Ruhl

Beilstein J. Org. Chem. 2024, 20, 2940–2945, doi:10.3762/bjoc.20.246

• dopants for liquid-crystal compositions. Keywords: chiral dopant; chirality; cholesteric phase; diols; fluorine; helical twisting power; liquid crystal; Introduction Liquid crystals for use in liquid crystal displays (LCDs) have become one of the most prominent application areas of fluoroorganic

• from neat chiral mesogens, or through the addition of a chiral dopant to an achiral nematic liquid crystal [5][6]. The ability of the dopant to induce chirality in the nematic phase is defined as the helical twisting power [HTP; β = (pc)−1; with p the helical pitch and c the molar concentration]. The

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

Formation of smectic phases in binary liquid crystal mixtures with a huge length ratio

• Nadia Kapernaum,
• Friederike Knecht,
• C. Scott Hartley,
• Jeffrey C. Roberts,
• Robert P. Lemieux and
• Frank Giesselmann

Beilstein J. Org. Chem. 2012, 8, 1118–1125, doi:10.3762/bjoc.8.124

• shrinkage of 1% at T−Tc = −8 K. Figure 6 shows the optical tilt angles of the mixtures, which were determined in the ferroelectric SmC* phase [6][7] to gain a better understanding of the unusual behavior of the layer spacing. To obtain a chiral SmC* phase, 4 mol % of the chiral dopant (R,R)-2-(4-octylphenyl

• mesogens 2PhP and PhP16 and of the chiral dopant MDW510. Acknowledgements This work was supported by the NSF/DFG program “Materials World Network” (DFG Gi 243/6) and by the Natural Sciences and Engineering Research Council of Canada.

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

• moment than those of cercosporin (1), therefore 2 should be more sensitive to solvent polarity (acetone has a dielectric constant of about 20 at room temperature). HTP predictions by the SC method Within the SC approach, the HTP of a chiral dopant in a nematic solvent is proportional to the so-called

Molecular length distribution and the formation of smectic phases

• Nadia Kapernaum,
• C. Scott Hartley,
• Jeffrey C. Roberts,
• Robert P. Lemieux and
• Frank Giesselmann

Beilstein J. Org. Chem. 2009, 5, No. 65, doi:10.3762/bjoc.5.65

• corresponding ferroelectric SmC* state [6] (see Figure 7) after addition of 4 mol % of the chiral dopant MDW510 ((R,R)-2-[4-(octyloxy)phenyl]-5-(2,3-difluorohexyloxy)pyridine) [7][8]. The pure compound PhP14 exhibits the highest tilt angles, with a quite regular value of about 27°. The addition of more and more

• ferroelectric switching of the tilt direction [19][20] in the achiral mixtures, 4 mol % of the chiral dopant MDW510 was added to receive chiral SmC* phases. The measurements of θ were taken at a field strength E of 12.5 V μm−1 as half the rotation between the two optical extinction positions corresponding to

• : a) Intra-layer segregation, b) Inter-layer segregation or c) Out-of-layer fluctuations. After [5][18]. Chemical formulas and phase sequences of the mesogens PhP14, 6PhPz and 2PhP and the chiral dopant MDW510. Acknowledgments We thank the Deutsche Forschungsgemeinschaft (DFG Gi 243/5) for financial

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

• intermolecular interactions and opposes director distortions [24]. Different theories [25][26][27] have contributed to elucidate the molecular mechanism behind cholesteric induction, as well as Molecular Dynamics simulations [28][29][30]; for the connection between structure of the chiral dopant and cholesteric

• geometries [59] were used. Within this approach, the HTP of a chiral dopant in a nematic solvent is proportional to the so-called chirality parameter Q, which holds the coupling of the chirality and orientational order and is proper of each dopant; the chirality parameter Q is defined as: where Sii is the