JPS6357553A - Liquid crystal - Google Patents

Abstract

NEW MATERIAL:A compound expressed by formula I (m, n and o are 0 or 1, provided that those are not simultaneously 0; R<1> is alkyl having 1-18C straight-chain or branched chain; R<2> and R<3> are each alkyl having 1-8C straight-chain or branched chain; X is single bond, -O-, -COO-, -OCO-, -COO-; Y and Z are single bonds, -COO- or -OCO-; Ph represents formula II, III, or IV or either one of these rings which is mono or di-substituted by halogen or cyano group). EXAMPLE:(S,S)-1-Methoxy-2-methylbuthylcarboxylic acid 4-(4- octylcarbonyloxyphenyl)phenyl ester. USE:The compound is useful as a constituent of liquid crystal composition. Further, the compound itself showing chiral smectic phase is also useful as a dopant of strongly dielectric liquid crystal. The compound is chemically stable, has large spontaneous polarization and is strongly dielectric at room temperature. PREPARATION:For example, a compound expressed by formula V is reacted with a compound expressed by formula VI to provide the aimed compound expressed by formula I.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a novel liquid crystal material and a liquid crystal composition containing the liquid crystal material, and in particular to a smectic liquid crystal composition.

Furthermore, in this specification, the term "liquid crystal substance" means a substance that is useful as a component of a liquid crystal composition even if it is not detected to exhibit a liquid crystal phase by itself.

BACKGROUND OF THE INVENTION Display systems for liquid crystal display devices that are currently in widespread use are twisted nematic type (TN type) and dynamic scattering type (DS type). These are nematic liquid crystals,
This is a display using a nematic liquid crystal cell as the main component. One of the disadvantages of conventional nematic liquid crystal cells is the fact that their response speeds are slow and can only be on the order of a few rm S e C at most. This is one of the factors that limits the range of applications of nematic liquid crystal cells. However, it has recently been found that a faster response can be obtained by using a smectic liquid crystal cell.

It has become clear that some optically active smectic liquid crystals exhibit ferroelectricity, and there are great expectations for their use. Liquid crystals exhibiting ferroelectric properties, ie ferroelectric liquid crystals, were developed in 1975 by R.B.
4-(4-n-decyloxybenzylideneamino)cinnamic acid-2-methylbutyl ester (hereinafter abbreviated as DOBAMBC) is a compound synthesized by Meyer et al., and its chiral smectic C
It is characterized by exhibiting ferroelectricity in the phase (hereinafter abbreviated as SmC* phase) (J, Phys.
1que, 3rd edition, L-69 (1975)).

In recent years, N, A, C1ark et al. (Appi, PhyS, L
ett, 36.89 (1980)), DOB
With the discovery of high-speed response on the order of μSeC in AMBC's cylindrical membrane, ferroelectric near-2 crystals have been used not only for displays such as LCD TVs but also for use in utilizing their high-speed response. It is attracting attention as a material that can be used for optoelectronic-related elements such as optical printer heads, optical Fourier transform elements, and light valves.

The following are representative compounds of ferroelectric liquid crystals known to date.

NeC+aflz+-0-O-CH=N-<iE>-CH=
CH-C0O-CH2-Cll-C2H5CH3 95→SC*→63°CPs<10nC/cT112C
8H1v-0-■-COO-<E+ -0-CH2-C
H(CH3)-C2R5ne58→SC*→43°CPs<1nC/ctn"C9H
I9-0-0-0-OCO-CH(CI)-CH(C
H3)-C2H5* *56-+5(J-+40oCPs=160nC/ciC
a11++-Ω-0-0-((J)3-CI(CH3)
-C2H5ne24→sc*-+8°CPs<1nC/cm"CIo)
12+-0-<E)-C00-O-0-CH2-C)1
(0-C21b)-C113* 28-+ SC*-) 8℃ Ps=15nC
/cm Problems to be Solved by the Invention In order to use ferroelectric liquid crystals for displays such as televisions, compounds having the following physical properties are required.

Exhibits ferroelectricity over a wide temperature range including room temperature.

It has a large spontaneous polarization and a fast response.

Chemically stable. As mentioned earlier, various ferroelectric liquid crystal compounds are known, but none of the known compounds satisfy all of these conditions. Therefore, there is a strong desire for a compound that is physically and chemically stable, has a large spontaneous polarization, and can be driven at room temperature as a ferroelectric liquid crystal material.

Furthermore, it is also necessary to mix a large number of compounds in order to obtain a ferroelectric liquid crystal material that can be put into practical use. and,
These compounds are desired to have, for example, the following physical properties.

It becomes a ferroelectric liquid crystal at high temperatures.

It becomes a ferroelectric liquid crystal at low temperatures.

Low viscosity. Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors searched for various liquid crystal materials and arrived at the present invention.

That is, the present invention provides general formula (I) RI-X-(Ph)m-Y-(Ph)n-Z-(Ph)
o-OCO-CH-R3(I)-R2, Pl represents a straight chain or branched alkyl group having 1 to 18 carbon atoms, and R2 and R3 each have 1 to 18 carbon atoms.
8 represents a straight chain or branched alkyl group, and X is a single bond, -0-1-〇〇〇-1-〇C0-1 or -oco
o-, Y and Z represent a single bond, -COO-1 or -CO-, and each ring is substituted with a halogen or a cyano group at one or two positions. )
A liquid crystal substance represented by and a liquid crystal composition containing the same (
I'm concerned.

In general, liquid crystal compounds have a rod-like structure consisting of a core consisting of a benzene ring or the like, and alkyl chains, alkoxyalkyl chains, etc. Among them, it is well known that those with alkyl chains and alkoxyalkyl chains having more than a certain number of carbon atoms tend to form a smectic phase. It is also well known that, in general, compounds having the same skeleton exhibit a similar phase series even if the lengths of the chain portions are slightly different.

In the above general formula (I), compounds in which R1 has 5 to 14 carbon atoms tend to form a chiral smectic C phase and are particularly useful as ferroelectric liquid crystal materials.

In addition, other compounds can also be used as compounding materials for ferroelectric liquid crystals.

The compound of formula (I) is synthesized as follows.

It can be synthesized by reacting a phenol represented by the following general formulas (a) and (i) with a carboxylic acid chloride together with a base such as pyridine in an inert solvent such as carbon tetrachloride.

R1-X-(Ph)m-Y-(Ph)n-Z-(Ph)
o-011 (a) R3-CH-COCI
(i) ■ -R2 In addition, a phenol represented by the following general formula (c) and a carboxylic acid chloride represented by the general formula (i) are mixed together with a base such as pyridine in an inert solvent such as carbon tetrachloride. Synthesized by reacting a phenol represented by the general formula (E) and a carboxylic acid chloride represented by the general formula (O) with a base such as pyridine in an inert solvent such as carbon tetrachloride. Good too.

No-Ph-OH (U) HO-Ph-OCO-C) I (0-R2)-R3 (E)
R1-X-(Ph)m-Y-(Ph)n-COCI
(e)Also, reacting a phenol represented by the following general formula (k) with a carboxylic acid chloride represented by the general formula (i) together with a base such as pyridine in an inert solvent such as carbon tetrachloride. The phenol synthesized by the general formula (g) and the carboxylic acid chloride represented by the general formula (<) may be reacted together with a base such as pyridine in an inert solvent such as carbon tetrachloride.

HO-Ph-Ph-OH(ka) HO-Ph-Ph-OCO-C1l(0-R2)-R3
(,ki)Rf-X-(Ph)m-COCI
(< ) Also, the general formula ( The carboxylic acid represented by formula (a) may be converted into an acid chloride using thionyl chloride or the like, and the mixture may be reacted with the phenol represented by formula (a) and a base such as pyridine in an inert solvent such as carbon tetrachloride.

1100cmPh-0)!
(ke))100C-Ph-OCO-C)! (0-R
2) -R3(,ko)R1-X-(Ph)m-Y-(Ph
) n-OH (S) It can also be synthesized by reacting a hydroxycarboxylic acid represented by the following general formula (C) with a carboxylic acid chloride represented by the general formula (C) in a base such as pyridine. The carboxylic acid represented by the general formula (S) is converted into an acid chloride using thionyl chloride, etc., and the general formula (S) is
It is also possible to react the phenol represented by (se) with a base such as pyridine in an inert solvent such as carbon tetrachloride.

)100C-Ph-Ph-Oft
(C)) 100cmPh-Ph-OCO-CH
(0-R2)-R3(su)R1-X-(Ph)m-OH
(S) In the above general formula (I), -0CO-C)I(OR2)-R
Those in which the group represented by 3 is optically active are particularly useful as ferroelectric liquid crystal materials. The optically active group here may be a naturally occurring one, an enzyme, a microorganism, an asymmetric catalyst, or the like, or an optically active oxyacid, amino acid, or the like obtained by optical resolution. In this case, the optically active amino acid is Va
It is used after being converted into an optically active oxyacid through the n5lyke reaction.

After esterifying these optically active oxyacids, they are treated with sodium hydride in anhydrous THF, and then an alkyl halide is added to obtain an alkoxycarboxylic acid ester. This is hydrolyzed by a conventional method to obtain an alkoxycarboxylic acid.

The alcohol used to esterify the oxyacid is not particularly limited, and examples include aliphatic alcohols such as methanol and ethanol, and aromatic alcohols such as phenol and biphenol derivatives.

The alkyl halide used in the alkoxylation is not particularly limited, but examples include methyl iodide, ethyl iodide, and isopropyl iodide.

Effect of the Invention The compounds of the present invention exhibit ferroelectric properties. Furthermore, among the compounds of the present invention, substances that do not become ferroelectric liquid crystals by themselves may also be used.
By mixing with ferroelectric liquid crystal materials, it can serve to adjust the ferroelectric liquid crystal temperature range without compromising its ferroelectric properties.

Among the compounds of the present invention, optically active compounds may be added to nematic liquid crystals for purposes such as white tiller type color display, cholesteric nematic phase transition type display, and prevention of reverse domain generation in TN type cells. It is possible.

Further, since the compound of the present invention becomes a smectic liquid crystal, it can also be used for memory type display elements such as thermal writing laser writing.

Effects of the Invention The compound of the present invention is chemically stable, exhibits ferroelectricity at room temperature, and has large spontaneous polarization. For example, unlike DOBAMBC, it does not have a ship base, so it is much more stable than DOBAMBC. In addition, the temperature range showing ferroelectricity is 63 to 92°C for DOBAMBC. The temperature drops to 18 to 24°C, which becomes a ferroelectric liquid crystal at room temperature. Further, the spontaneous polarization of this compound is as large as 66 nC/ctn''.

Also, for example, (S,5)-4-(1-methoxy-2-
Methylbutylcarbonyloxy)phenyl-4-(4-
Octylcarbonyloxyphenyl)benzoic acid ester exhibits ferroelectricity in the high temperature range of 75 to 125°C. By adding this compound to a ferroelectric liquid crystal composition, the temperature range of the composition can be expanded.

Furthermore, since the compound of the present invention contains an optically active group, even a compound that does not exhibit a chiral smectic phase by itself is useful as a dopant for ferroelectric liquid crystals.

EXAMPLES The compounds of the present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples.

Hereinafter, C, SC*, SA, and I phases represent crystal, chiral smectic C, smectic A, and isotropic liquid phases, respectively.

Example 1 (S,5)-1-methoxy-2-methylbutylcarvone! Synthesis of 4-(4-octylcarbonyloxyphenyl)phenyl ester (A) Ca11+7-C00-■-@-0CO-Ctl(0-
CH3)-C)I((Jla)-C2Hs* Neargon-substituted! 5mL anhydrous TH in a 50mL flask
F and 1.27 g sodium hydride (55% content) are added and stirred with a magnetic stirrer. Zero the reaction vessel
3,0 g (S,5)- obtained in a known manner from L-isoleucine in an isobaric bottom funnel while cooling to
1-Hydroxy-2-methylbutylcarboxylic acid ethyl ester and 5 mL THF are carefully added dropwise over about 10 minutes. Bring it back to room temperature, heat it indirectly for about 15 minutes, and then heat it again to 0.
Cool to °C, 3.3 mL methyl iodide and 5 mL TH
Add F dropwise over about 15 minutes. After stirring at room temperature for about 1 hour, hydrolyze with 20 mL of water.

Add 20ml of 5% potassium hydroxide aqueous solution and stir for a while. After extracting the aqueous layer three times with 20 mL of ether,
The ether layer was washed with aqueous sodium thiosulfate and then with saturated brine, dried over magnesium sulfate, and the ether was distilled off. By distilling under reduced pressure, 2.1 g of (S,5)-
1-Methoxy-2-methylbutylcarboxylic acid is obtained.

After refluxing 1.46 g of (S,S')-1-methoxy-2-methylbutylcarboxylic acid with 2 ml of thionyl chloride for 2 hours, the solvent was distilled off, and (S,5)-1-methoxy-
Obtain 2-methylbutylcarboxylic acid chloride.

2.6 g of 4-(4-octylcarbonyloxyphenyl)phenol was dissolved in 10 ml of pyridine, and the above (S
, 5) Add a mixture of -1-methoxy-2-methylbutylcarboxylic acid chloride and 100 ml of carbon tetrachloride, and stir for a while. - Leave to cool overnight, filter out the precipitated crystals, and concentrate. Purification by silica gel ram and recrystallization from methanol gives the product.

The IR spectrum of the compound is shown in FIG.

This compound is a smectic liquid crystal compound exhibiting an SC main phase, and its phase transition temperature is shown in Table 1.

Using a polyethylene terephthalate film with a thickness of 25 μm as a spacer, (A) was sealed in a cell made of Nesa glass, and an alternating current of 300 H2 was applied.
- Spontaneous polarization was measured by the Tower method. the result,
The maximum value of spontaneous polarization in (A) is 66 nC/cm,
It was found that it has a very large spontaneous polarization.

Furthermore, (A) was sealed in a cell made of Nesa glass using a polyethylene terephthalate film as a spacer, and the electro-optic effect was observed under a microscope by applying a square wave. In addition to very clear contrast, a quick response was visible, proving that this compound can be applied to liquid crystal displays.

Example 2 Synthesis and physical properties of (S, 5)-4-(1-methoxy-2-methylbutylcarbonyloxy)phenyl 4-(4-octylcarbonyloxyphenyl)benzoic acid ester Ca HI 7-COO-■-■ -Coo-0-OCO
-CO-CH(Ch)-C2HsO-CH3 11.0 g of hydroquinone is dissolved in 50 ml of lysine. While stirring vigorously, 8.2 g of (S,5)-1-methoxy-2-methylbutylcarboxylic acid chloride was added and stirred for 2 hours. Neutralize with hydrochloric acid and extract with chloroform. The chloroform phase was concentrated and purified using a silica gel column to obtain S,5)-4-(1-methoxy-2-methylbutylcarbonyloxy)phenol.

(S,S) -2.4 g of -4-(1-methoxy-2-methylbutylcarbonyloxy)phenol was added to 10 g of pyridine.
3.5 g of 4-(4-octylcarbonyloxyphenyl)benzoic acid chloride and 1 carbon tetrachloride dissolved in ml
Add the mixture of 00ml and stir for a while. - Set aside overnight, filter out the precipitated crystals, and concentrate. Purified by silica gel column and recrystallized from methanol.
)-4-(1-methoxy-2-methylbutylcarbonyloxy)phenyl 4-(4-octylcarbonyloxyphenyl)benzoic acid ester is obtained.

This compound is a smectic liquid crystal compound exhibiting an SC main phase, and its phase transition temperature is shown in Table 1. Also,
The maximum value of its spontaneous polarization was 32 nC/c n''.

Example 3 The phase transition temperatures of compounds synthesized in the same manner as in Examples 1 and 2 are summarized in Table 1.

[Brief explanation of drawings]

Figure 1 shows (S,5)-1-methoxy-2- obtained in Example 1.
The infrared absorption spectrum of methylbutylcarboxylic acid 4-(4-octylcarbonyloxyphenyl)phenyl ester is shown.

Claims (6)

[Claims] (1) General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (However, in the above formula, m, n, and o are not 0 at the same time.
or 1, R1 represents a straight chain or branched alkyl group having 1 to 18 carbon atoms, R2 and R3 each represent a straight chain or branched alkyl group having 1 to 8 carbon atoms, and X
is a single bond, -O-, -COO-, -OCO-, or -OCOO-; Y and Z are a single bond, -COO-,
or -OCO-, Ph is ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼,▲
There are mathematical formulas, chemical formulas, tables, etc.▼ and these rings are substituted with one or two halogens or cyano groups. ). (2) In general formula (I), -R2 is -CqH_2q+1,
-R3 is -CH(CH_3)-C_2H_5, the following general formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I
I) (However, q represents a natural number from 1 to 8.) The compound according to claim (1) (3) In general formula (I), -R2 is -CqH_2q+1,
-R3 is -CH(CH_3)_2, the following general formula (
III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (III) (However, q represents a natural number from 1 to 8.) Compound described in claim (1) (4) In general formula (I), -R2 is -CqH_2q+1,
-R3 is -CH_2-CH(CH_3)_2, the following general formula (IV) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I
V) (However, q represents a natural number from 1 to 8.) The compound according to claim (1) (5) In general formula (I), -R2 is -CqH_2q+1,
-R3 is -CH_3, the following general formula (V) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(V) (However, q represents a natural number from 1 to 8.) ) Compounds described in section (6) General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (However, in the above formula, m, n, and o are not 0 at the same time.
or 1', R1 represents a straight chain or branched alkyl group having 1 to 18 carbon atoms, R2 and R3 each represent a straight chain or branched alkyl group having 1 to 8 carbon atoms,
X is a single bond, -O-, -COO-, -OCO-, or -OCOO-; Y and Z are a single bond, -COO-
, or -OCO-, Ph is ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼,
▲There are mathematical formulas, chemical formulas, tables, etc.▼ and these rings are substituted with one or two halogens or cyano groups. ) A liquid crystal characterized by containing at least one compound represented by: