JPS61140535A - Novel tolan-type nematic liquid crystal compound - Google Patents

Abstract

NEW MATERIAL:The compound of formula I [R and R' are 1-9C straight-chain alkyl/ n is 0 or 1; the confifguration of the cyclohexane ring is trans(equatrial)]. EXAMPLE:The comopound of formula II. USE:Useful as a liquid crystal material. It is a nematic liquid crystal compound having weak negative dielectric anisotropy. It can be used as a material of a dynamic light-scattering display cell by mixing with other nematic liquid crystal compound, or as a material of a field-effect display cell as a mixture with other nematic liquid crystal compound having strong positive dielectric anisotropy. PREPARATION:The compound of formula I can be prepared by reacting the alkyl benzyl ether of formula III with iodine in a solvent, and reacting the resultant compound e.g. with 4-n-alkylphenylacetylene in the presence of a catalyst such as bis(triphenylphosphine)palladium(II) chloride in a solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel nematic liquid crystal compounds of transconductors useful as electro-optic display materials. The novel nematic liquid crystal compound provided by the present invention is a typical type of general liquid crystal display cell.
@hadt ) etc. [APPLIED PHYSIC8I
JTTER 8, 127-128 (1971)) or the field effect cell proposed by G. H. Beilmeier (1971).
G@HH@i1meier) etc. (PROCEEDIN
G 0FTHE Ill, Σ, 561162~117
1 (1968)) or the dynamic scattering mode cell proposed by G.H. Beilmeier (GaHHe11m@l).
@r) etc. [MuPPLIED PHY8IC8LETTE
R813,91 (19 (S8)) A certain Hani is DL White (DLWhit・) etc. (JOTJRNAL
0FAPPLIED PHYSIC845,471
8 (1974)) and the guest-host type cell proposed by K.

Among these liquid crystal display cells, the one currently mainstream is a TN type cell, which is a type of field effect cell. In this TN type, Mo1. Cry
st, Liq Cryst.

As reported in 65 45 (1981), the ninth step to prevent the occurrence of interference fringes on the cell surface that impairs the appearance of the cell is to improve the anisotropy of the refractive index of the liquid crystal material filled in the cell. It is necessary to set the product of the cell thickness (Δ0 and the cell thickness d) to a specific value. In practically used liquid crystal display cells, the value of Δn-d is n, s, to, '1.6 or 2.
It is set to one of 2. Since the value of Δnod is thus set to a constant value, the value of d can be made small by using a liquid crystal material with a large value of Δn.

When the dO value becomes small, the response time (τ) becomes small according to the well-known relational expression 9ταd2. Therefore, a liquid crystal material with a large value of Δn is an extremely important material for manufacturing a liquid crystal display cell that has a fast response speed and is free from interference fringes.

The compound of formula (I) according to the present invention is a novel nematic liquid crystal compound having a large Δn. Therefore, by mixing the compound of formula (I) with various parent liquid crystals, a practical mixed liquid crystal material having a large Δnt- can be prepared.

The compound of formula (II) according to the present invention can be produced according to the following production method.

Step 1 - A compound of formula (2) is prepared by reacting an alkyl benzyl ether with iodine in a mixed solvent of acetic acid and water.

2nd stage - the large-sided compound produced in the 1st stage is
4-n-alkylphenylacetylene or 4-()lanth-4-n-alkylcyclohexyl)phenylacetylene using a catalyst such as bis(triphenylphosphine)palladium chloride in a solvent such as N-dimethylformamide. The reaction produces a compound of formula (I).

Table 1 lists the transition temperatures of representative compounds of formula (I) thus produced.

The compounds of formula (I) according to the present invention are many nematic liquid crystal compounds with weak negative dielectric anisotropy, and therefore, for example,
It can be used as a material for dynamic light scattering display cells in a mixture with other nematic liquid crystal compounds that have negative or weak-positive dielectric anisotropy, and it can also be used as a material for dynamic light scattering display cells. It can be used as a material for field effect display cells in the form of a mixture with other nematic liquid crystal compounds.

Thus, preferred representatives which can be used in admixture with compounds of formula (I) include, for example, 4,4'-substituted benzoic acid phenyl ester, 4,4'-substituted cyclohexanecarboxylic acid phenyl ester, 414 '-substituted cyclohexanecarboxylic acid biphenyl ester, 4(4
-Substituted cyclohexanecarbonyloxy)benzoic acid 4'
-substituted phenyl ester, 4(4-substituted cyclohexyl)benzoic flR4'-substituted phenyl ester, 4(4-substituted cyclohexyl)benzoic
[Substituted cyclohexyl]benzoic acid 4'-substituted cyclohexyl ester, 4.4'-substituted biphenyl, 4°4'-R
substituted phenylcyclohexane s 4 e 4'-substituted ter-yxyl, 4, 4'-biphenylcyclohexane, 2
(4'-substituted phenyl)5-substituted pyrimidine, etc. can be mentioned.

Table 2 shows 90% by weight and
The anisotropy (Δn) of the refractive index measured for each mixed liquid crystal consisting of 10% by weight of each of the compound 1, 42, 430 of the formula (I) shown in the table is shown, and for comparison, the anisotropy of the refractive index Δn measured for the liquid crystal (4) itself is displayed.

In addition, the parent liquid crystal is and Table 2 Mixed liquid crystal Δn(-4 (A) 0.0917 +141 Q, 104 (A) + Na2 0.103 +l'1 & L3 0.110 Example ■ Acetic acid 122 Jlj, Water 2311/ and carbon tetrachloride 1511
Percoron 11!7.1F (0,031
0 mol) and iodine 3&777 (0,138 mol)
) and methylbenzi/l/x-tepv32
．． 311 (Q, 265 mol) f was added, and the mixture was heated under reflux for 20 hours.

After the reaction is complete, sodium bisulfite 321 (0,30
A solution of 0 mol ) dissolved in 200 d of water was added, the product was extracted with ether, the extract was washed with water, dried, and after distilling off the ether, it was subjected to vacuum distillation to obtain the following compound 4511 ((
1182 mol) t-obtained.

This compound 7.5.9 (0,0300 mol)'iN,
Dissolved in N-dimethylformamide 50117 and added bis(triphenylphosphine)palladium(2) to this solution.
) Chloride 10η (o, 0142 mmol), cupric iodide 5011F ([L263 mmol) and diethylamine 2 g (α274 mol) fe were added, and under stirring, 4-n-pentylphenylacetylene 5゜2II (0,
0300 mol) t- was added, and the mixture was reacted at room temperature for 1 hour.

After the reaction was completed, 501,117 tons of 9% hydrochloric acid was added, and the product was extracted with toluene. The extract was washed with water and dried. After distilling off the toluene, the entire product was purified by recrystallization with methanol to obtain 4Jl of the following compound.

Yield: 46% Transition temperature: 39℃ (C → Engineering) 9'C (I'tiN) Example 2 The following compound was obtained in the same manner as in Example 1.

Yield: 42% Transition temperature: -25℃ (C → Engineering) Example 3 The following compound was obtained in the same manner as in Example 1.

Yield 40% Transition temperature 108℃ (C-48) 112℃ (SdN) 196℃ (N:!I) Agent: Patent Attorney Katsutoshi Takahashi

Claims (1)

[Claims] General formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, R and R independently represent a linear alkyl group having 1 to 9 carbon atoms, and n is 0 or 1. The cyclohexane ring is in the trans (equatorial) configuration. A compound represented by ]