Synthesis and Physicochemical Properties of Novel Liquid Crystal Compounds with Negative Dielectric Anisotropy with a Tetrahydropyran Ring: Part 2

Abstract

With the aim of improving the properties of liquid crystal (LC) mixtures for VA-LCD and PSA-LCD, JNC has newly synthesized 2-(4’-ethoxy-2’,3’-difluorobiphenyl-4-yl)-5-alkenyltetrahydro-2H-pyran derivatives with alkenyl substituents as side chains, and then measured various physicochemical properties to compare their properties to LC compounds with alkyl substituents as side chains. We have shown that several LC compounds with side-chain alkenyl substituents lead to the development of a larger negative dielectric anisotropy (Δϵ) than for side-chain alkyl substituents. We considered the reason for this using a quantum chemical calculation. As a result, it was found that, compared to alkylated compounds, there exist several LC compounds with side-chain alkenyl substituents, which have a higher existence probability of conformers with a β angle, making expression of a larger |Δϵ| possible in an effective manner. It was understood from this study that the physicochemical properties of LC mixtures for VA-LCD and PSA-LCD, which consist of LC compounds as a structural component, newly developed by JNC, show useful properties.

Keywords:

• Alkenyl substituent
• negative dielectric anisotropy
• PSA-LCD
• quantum chemical calculation
• tetrahydropyrane derivatives
• VA-LCD