Acetylene derivatives, process for producing the same, liquid cr

Details Acetylene derivatives, process for producing the same, liquid cr Acetylene derivatives, process for producing the same, liquid cr

1994-06-24

1996-07-09

Tsang, Cecila

Compositions

Liquid crystal compositions

Containing nonsteryl liquid crystalline compound of...

560100, 560113, 560122, 560123, 560124, 560129, 560187, 560219, 560221, 560228, 568643, 568659, 25229966, 544224, 544238, 544239, 544296, 544295, 544316, 544318, 544319, 544333, 544336, 544405, 544408, 546258, 546257, 546301, 546302, 546342, 546339, C09K 1912, C09K 1930, C07D23902, C07D21362

Patent

active

055341888

DESCRIPTION:

BRIEF SUMMARY
TECHNICAL FIELD

1. Background Technique
This invention relates to acetylene derivatives useful as an ingredient of ferroelectric liquid crystal compositions, a process for producing the same, compounds obtainable from the acetylene derivatives and a process for producing said compounds, liquid crystal compositions containing said compounds as active ingredient, and liquid crystal elements using said liquid crystal compositions.
2. Background Technique
At the present time, TN (twisted nematic) type displaying methods are most widely employed in the field of liquid crystal elements. TN liquid crystal elements have many merits such as lowness in driving voltage, smallness in consumption of electric power, etc. In the point of response speed, however, the TN liquid crystal elements are inferior to luminescence type display elements such as cathode tube, electroluminescence, plasma display and the like. Although a new TN type display element in which the angle of twist is altered to 180.degree. to 270.degree. has been developed, it is still insufficient in response speed. In spite of such endeavors for improvement as the above, a TN type display element having a high response speed is not yet realized. However, there is a possibility of marked improvement in response speed in the new displaying method using a ferroelectric liquid crystal which is energetically being studied in the recent time (Clark et al.; Applied. Phys. Lett., 36, 899 (1980)). This method uses a chiral smectic phase exhibiting a ferroelectricity such as chiral smectic C phase (hereinafter, abbreviated to Sc*), etc. It is known that the phase exhibiting a ferroelectricity is not limited to Sc* phase, but chiral smectic F, G, H and I phases and the like also exhibit a ferroelectricity.
Ferroelectric liquid crystal materials used in practical ferroelectric liquied crystal elements are required to have many characteristic properties. At the present stage, such requirements cannot fully be satisfied by a single compound, but a ferroelectric liquid crystal composition obtained by mixing together a number of liquid crystal compounds or (non-liquid crystal) compounds must be used for satisfying such requirements.
A ferroelectric liquid crystal composition can be obtained not only by using a composition composed of ferroelectric liquid crystal compounds alone. Thus, it has been reported in JP-A-61-195187 that a ferroelectric liquid crystal composition, as a whole, can be obtained by using a compound and composition showing non-chiral smectic C, F, G, H, I phases, etc. (hereinafter, abbreviated to Sc phase, etc.) as a fundamental substance and mixing thereinto one or more compounds showing ferroelectric liquid crystal phase. Further, in another paper (Mol. Cryst. Liq. Cryst., 89, 327 (1982)), it has been reported that a ferroelectric liquid crystal composition, as a whole, can be obtained by using a compound and composition showing the Sc phase, etc. as a fundamental material and mixing thereinto one or more compounds which are optically active and show no ferroelectric liquid crystal phase.
Considering these facts collectively, it can be understood that a ferroelectric liquid crystal composition can be constituted by using one or more optically active substances as fundamental material, whether these compounds show ferroelectric liquid crystal phase or not. However, it is desirable that the optically active substance shows a liquid crystal phase and, even if the optically active substance does not show liquid crystal phase, it is a pseudo liquid crystal substance or a substance of which structure resembles that of liquid crystal compound. However, up to today, there has been discovered no liquid crystal material having a spontaneous polarization necessary for a high-speed response, having a low viscosity and showing ferroelectric liquid crystal phase in a sufficiently broad temperature range involving the ambient temperature range.
As a known paper having a relation with this invention, JP-A-4-141969 can be referred to, wherein are disclosed olefin-t

REFERENCES:
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patent: 4834904 (1989-05-01), Krause et al.
patent: 5047172 (1991-10-01), Saito et al.
patent: 5167859 (1992-12-01), Wachtler et al.
patent: 5326497 (1994-07-01), Buchecker et al.
patent: 5366657 (1994-11-01), Illian et al.
Dieck, H. A. et al. J. Organomet. Chem. 93, 259-263 (1975).
CHEMICAL ABSTRACTS, vol. 113, No. 12, 17 Sep. 1990, Columbus, Ohio, US; abstract no. 106585, SUGAWARA S, "Optically active diphenylacetylene derivatives and liquid-crystal compositions containing them" & JP-A-89 301 639 (NIPPON TELEGRAPH AND TELEPHONE CORP., JAPAN), 5 Dec. 1989.

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