JPH0867822A - Anthraquinone derivative, liquid crystal composition using the same and liquid crystal element - Google Patents

Abstract

PURPOSE: To obtain a new compound giving a liquid crystal element having a higher displaying effect as a pigment for correcting hue in a guest-host type mode, because of having a negative or a low positive yellow-red dichroism, especially having an excellent stability. CONSTITUTION: This compound is expressed by formula I (Rf is H or a perfluoroalkyl; X is expressed by formula II; Y is expressed by formula II or formula III; R is H, an alkyl, etc.; (n) is 0 or 1). The compound is obtained by reacting anthraquinones expressed by formula IV with a perfluoroalkyl- containing acid halide compound of the formula Rf-Xn -COC1, e.g. by suspending the compound of formula I in chloroform and dropping the compound of formula II to the suspension under refluxing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel yellow to red anthraquinone derivative having a negative dichroism useful for liquid crystal display, a liquid crystal composition using the same, and a liquid crystal device.

[0002]

2. Description of the Related Art At present, various display modes such as a twist nematic (TN) type display mode and a super twist (STN) mode are used as a liquid crystal display. A guest-host (GH) type display mode in which a dye is dissolved in a liquid crystal compound is widely used as a display panel for automobiles and the like because of its features such as wide viewing angle.

The GH mode is a TN mode and a TN mode.
-It has a feature that it can be used in combination with other modes such as GH mode. Therefore, the dye used is required to have various characteristics depending on the purpose of use and the display mode. The requirements for dichroism are diverse. Among them, a dye having a negative dichroism is useful as a positive guest-host type display or for hue correction of a compounding color, but most yellow to red dyes having these characteristics are known. Absent.

The present invention provides a yellow to red dye having excellent stability and a dye having a negative to low positive dichroism, a liquid crystal composition using the same, and a liquid crystal device using the liquid crystal composition. The purpose is.

[0005]

The gist of the present invention is to provide the following general formula [I] in claim 1.

[0006]

[Chemical 4]

(In the formula, Rf represents a hydrogen atom or a perfluoroalkyl group which may be substituted with a chlorine atom, and X represents

[0008]

[Chemical 5]

And Y is

[0010]

[Chemical 6]

R represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or Rf, and n represents a number of 0 or 1. ), An anthraquinone derivative represented by the formula (1) and a liquid crystal composition containing at least one derivative thereof, and a liquid crystal device having the liquid crystal composition sandwiched between at least one transparent substrate. is there.

As Rf in the above general formula [I],
_{-CF 3, -C 2 F 5,} -C 3 F 7, -C 4 F 9, -C 6 F 13,
_{-C 7 F 15, -C 9 F} 19 perfluoroalkyl group having 1 to 12 carbon atoms, such _{as, -C 4 F 8 H, -C} 6 F 12 H atoms are substituted with hydrogen atoms, such as 1 to 12 perfluoroalkyl _{group, -CClF 2, -CF 2 (CClFCF} 2) 2 Cl is a perfluoroalkyl group having 1 to 12 carbon atoms which is substituted by chlorine atoms, and the like.

R is an alkyl group having 1 to 12 carbon atoms such as methyl, ethyl, linear or branched propyl, butyl, hexyl, octyl, methoxy, ethoxy,
Examples thereof include linear or branched propoxy, butoxy, hexyloxy, octyloxy, and other alkoxyl groups having 1 to 12 carbon atoms. Examples of Rf include the same as the above Rf, and Rf in R includes Particularly, an unsubstituted perfluoroalkyl group having 1 to 12 carbon atoms is preferable.

As X

[0015]

[Chemical 7]

And the like. For Y

[0017]

Embedded image

[0018] n represents the number of 0 or 1. The anthraquinone derivative represented by the general formula [I] of the present invention is a novel compound, and the compound is represented by the anthraquinone represented by the general formula [II] and the general formula [III] as represented by the following formula. Can be synthesized by reacting an acid halide having a perfluoroalkyl group described above in the presence or absence of a deoxidizing agent such as pyridine.

[0019]

[Chemical 9]

(In the formula, X, Y, R, n and Rf have the same meanings as in the above-mentioned general formula [I].) The liquid crystal composition of the present invention comprises the anthraquinone derivative having the specific structure of the present invention, A liquid crystal composition containing a liquid crystal substance, which exhibits a positive dichroism having an order parameter of 0.5 or more, while a normal anthraquinone dye shows a low dichroism near negative or zero. It has a distinctive feature in that it exists.

The liquid crystal composition of the present invention contains the anthraquinone derivative represented by the general formula [I] shown above in [Liquid Crystal Device Handbook; Japan Society for the Promotion of Science, 142nd Committee, ed.
9); p154 to p192, p715 to p722], and various liquid crystal compounds or liquid crystal compositions exhibiting a nematic or smectic phase such as biphenyl, phenylcyclohexane, phenylpyrimidine, cyclohexylcyclohexane and the like, are mixed by a known method. Therefore, it can be easily prepared. Examples of such liquid crystal compounds include the compounds described in JP-A-3-14892. In addition to this, a fluorine-based liquid crystal such as a TFT liquid crystal element can be preferably used.

The liquid crystal composition of the present invention may also contain an optically active compound such as cholesteryl nonanoate, which may or may not exhibit a liquid crystal phase, or various kinds of UV absorbers, antioxidants and the like. You may contain an additive.
An element applying the guest-host effect by sandwiching the liquid crystal composition thus obtained between substrates having at least one transparent electrode [Shoichi Matsumoto, Ichino Tsunoda “Latest Liquid Crystal Technology” Industrial Survey Kai, 34 (1983); L. F
ergason, SID85Digest, 68 (19)
85) etc.] and the like can be configured. The substrate is usually a glass plate or various synthetic resin plates such as acrylic resin, polycarbonate resin, epoxy resin, etc., and an electrode layer is formed on the substrate. As the transparent electrode layer,
Those composed of metal oxides such as indium oxide, indium tin oxide (ITO) and tin oxide are usually used. The surface of the transparent electrode layer which is in contact with the liquid crystal is subjected to an alignment treatment, if necessary. As the method of the alignment treatment, a method of applying polyimide for parallel alignment, a method of vapor-depositing SiO from an oblique angle for alignment, and the like are appropriately used.

The bases are integrated with each other with a spacer or the like so that the surfaces of the alignment treatment layers face each other, and usually 1 to 50 μm.
m, preferably 1 to 15 [mu] m elements are formed, and liquid crystal is sealed in the elements.

[0024]

INDUSTRIAL APPLICABILITY The present invention relates to a dye having a negative or low positive dichroism, a liquid crystal composition and a liquid crystal device using the same, which is used for hue correction in a guest-host type mode and has a better display. It is possible to realize a liquid crystal element having an enhanced effect.

[0025]

EXAMPLES Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. Example 1 Anthraquinone derivative represented by the following structural formula

[0026]

[Chemical 10]

1.2 g was suspended in 80 ml of chloroform.
And reflux it while Cl (CF ₂CClF)₂CF
₂After dropwise adding 9.6 g of COCl, reflux was continued at the same temperature.
The reaction was allowed to proceed for 2 hours with stirring. After the reaction, evaporate the solvent and
Purify and separate the target product by Lamb chromatography,
Recrystallized with chloroform / hexane to give the following structural formula

[0028]

[Chemical 11]

A compound represented by This compound had a melting point of 227 to 229 ° C. and a maximum absorption wavelength (λmax) in chloroform of 471 nm. Example 2 By the method according to Example 1, the compounds shown in Table 1 were obtained. The maximum absorption wavelength (λmax) in chloroform of the obtained compound is shown in Table-1.

[0030]

[Table 1]

Example 3 A trade name of ZLI-4792 was E. A liquid crystal composition was prepared by adding 0.5% by weight of the compound obtained in Example 1 to a fluorine-based liquid crystal mixture commercially available from MERCK.
A transparent glass substrate with an electrode was subjected to a homogeneous alignment treatment so that the electrodes faced each other and had a thickness of 50 μm.
Then, the liquid crystal device was manufactured by enclosing the liquid crystal device in a cell. Absorption spectrum for polarized light parallel to the alignment direction of this liquid crystal element (A /
/) And the absorption spectrum (A⊥) for linearly polarized light perpendicular to the orientation direction were measured. From these absorption spectrum values, the order parameter (S) is calculated by the following formula.

[0032]

[Formula 1] S = (A //-A⊥) / (A // + 2A⊥) As a result, a negative value (S = -0.26: λmax
= 483 nm). Example 4 The order parameter (S) of the compounds represented by 2-2 and 2-7 of Example 2 was measured in the same manner as in Example 3. Table 2 shows the results.

[0033]

[Table 2]

[0034]

[Table 3]

Claims (3)

[Claims] 1. An anthraquinone derivative represented by the following general formula [I]. Embedded image (In the formula, Rf represents a perfluoroalkyl group which may be substituted with a hydrogen atom or a chlorine atom, and X represents And Y is R represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or Rf, and n represents a number of 0 or 1. ) 2. A liquid crystal composition comprising a liquid crystal compound and at least one anthraquinone derivative according to claim 1. 3. A liquid crystal device comprising the liquid crystal composition according to claim 2 sandwiched between two substrates with electrodes, at least one of which is transparent.