Sadao Takehara

New chiral dopants for FLC materials: optically active cyclic ethers

Abstract A series of new optically active cyclic ethers such as tetrahydrofurans, chromans and dihydrobenzofurans were synthesized, and their physical properties as a chiral dopant for FLC were investigated. Correlation between the the chemical structures and the physical properties, especially spontaneous polarization (Ps), are discussed and compared with that of the corresponding lactones.

Synthesis and properties of optically active 1,3-diols and their derivatives as chiral dopants for ferroelectric liquid crystals

Abstract New chiral dopants β-hydroxy ketones 1, 1,3-diols 2, 1,3-dioxanes 3 and 1,3-dioxan-2-ones 4 were designed and synthesized. Reaction of (R)-1,2-epoxyoctane with carbanions derived from 2-(4-substituted phenyl)-1,3-dithianes followed by hydrolysis of the resulting hydroxy dithianes afforded 1. Reduction of 1 gave the diols 2, which yielded 3 upon acetalization and 4 upon carbonation. The syn isomers of 2, 3, and 4 exhibited larger spontaneous polarizations, when applied as chiral dopants, than the anti isomers or hydroxy ketones 1.

Synthesis of optically active α-cyanobenzyl alkyl ethers

Abstract The title ethers, expected chiral dopants for ferroelectric liquid crystals, were prepared by the allylation of chiral cyanohydrins under the acidic conditions followed by hydrogenation, or alternatively by the Johnsons cyanation of chiral acetals followed by fluorination.

Design, synthesis and properties of new ferroelectric liquid crystalline compounds having a chiral center directly connected to the core aromatic ring

Abstract Synthesis and opto-electrical properties of new chiral dopants α-aryl-γ-alkyl-γ-lactones, 3-aryl-5-alkyl-oxazolidin-2-ones and 2-alkyl-1-aryl-1-cyanocyclopropanes for ferroelectric liquid crystals are discussed.

Physical property of new liquid crystal materials and mixture design for active matrix LCD

Abstract We studied the physical properties of three series of new fluorinated liquid crystal components and prepared some mixtures by using these components. Decahydronaphthalenes have low Δn with relatively high T NI. Naphthalenes and Tetrahydronaphthalenes have large Δϵ and variety range of Δn (0.08–0.21). Moreover, we have revealed that the fluoro- substituent at C-1 position for the naphthalene and the tetrahydronaphthalene ring has effects to increase T NI and to reduce γ1 with good solubility. Then, we have designed some LC mixtures for AM-LCD having good performance with 4V-driving, quick response, high birefringence, low birefringence, wide temperature range and low driving voltage.

Synthesis and electro-optical properties of 3-substituted phenyl trifluoromethyl ethers

Abstract A convenient synthetic method is described for 3-substituted aromatic trifluoromethyl ethers through an oxidative desulfurization–fluorination reaction. Upon addition to liquid crystalline materials, these ethers lower birefringence (Δ n ) of the host liquid crystals.

Components for host mixtures of FLC

Abstract Some liquid crystal materials are presented and discussed useful to improve the physical properties of a host mixture for FLC, for example, their temperature range, phase sequences, viscosity and response time.

Synthesis and properties of new optically active γ-lactones as chiral dopants for ferroelectric liquid crystals

Optically active α-aryl-γ-alkyl-γ-lactones were synthesized through the reaction of chiral 1,2-epoxyalkanes with the carbanion derived from 4-methoxyphenylacetonitrile or 4-methoxyphenylacetic acid and shown to be good chiral dopants for ferroelectric liquid crystals.

Design, synthesis and properties of new chiral dopants for ferroelectric liquid crystals

Abstract Synthesis and electro-optical properties of following chiral dopants for ferroelectric liquid crystals are discussed: compounds having an acyclic chain with a chiral center directly connected to both a core aromatic ring and a polar group, and compounds having a chiral ring with a polar group.

Correlation between absolute configuration of benzylic chiral centre and sign of spontaneous polarization of chiral dopants for ferroelectric liquid crystals

The absolute configuration of a polar-group-substituted benzylic chiral carbon of a chiral dopant for ferroelectric liquid crystals is found to be predictable by the sign of spontaneous polarization of the ferroelectric liquidcrystalline mixtures containing the chiral dopant.