JPS60202830A - Novel phenylalkylacetylene based nematic liquid crystal compound - Google Patents

Abstract

NEW MATERIAL:A phenylalkylacetylene based nematic liquid crystal compound of formula I [R and R' are 1-9C straight chain alkyl group; cyclohexane ring is (equatorial-equatorial) configuration]. EXAMPLE:The compound of formula II. USE:Useful as an electrooptical display material, having a low viscosity, relatively high DELTAn value and high N-I transition temperature, and usable as a material for dynamic scattering type display cells in the state of a mixture with another nematic liquid crystal compound having negative or weakly positive dielectric anisotropy further as a material for electric field effect type display cells in the state of a mixture with another nematic crystal compound having strong positive dielectric anisotropy. PREPARATION:A compound of formula III is reacted with a compound of formula IV and anhydrous aluminum chloride, and the resultant product is reacted with a reducing agent and then a dehydrating agent to given a product, which is then reacted with bromine and then a base to afford the compound of formula I .

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel enylalkyl acetylene-based nematic liquid crystal compounds useful as electro-optic display materials.

The novel nematic liquid crystal compound provided by the present invention is a compound represented by the general formula.

M-Shut (M-8) is a typical liquid crystal display cell.
shadt) etc.[:APPLIED PHYSIC8L
ETTER8υshi 127-128 (1971)] or the field effect mode cell proposed by G.H.
G-HHsi1mei@r ) etc. [PROCEEDIN
G OF THEIJJ, E, Dan 6 1162-117
1 (1968)], a dynamic light scattering cell (
Diminc scattering mode cell) or G-HHsilmeier (G-HHsilmeier)
) etc. (APPLIED PHY8IC8LETTER8
13.? 1 (1968)) or D.L.
White (DL White) etc. (JOURNAL
0FAPPLIED P)rYsIcs 45.47
18 (1974)].

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 cell, Mol, C by G, Bauer
ryst, Llq.

As reported in Cryat. It is necessary to set the product of the anisotropy (Δn) and the cell thickness (d) μm to a specific value. In a practically used liquid crystal display cell, the value of Δn−d is 0.5.1.
It is set to either 0, 1.6 or 2.2. Since the value of Δnbd is set to a constant value in this way, Δn
By using a liquid crystal material with a large value of d, the value of d can be made small. If the value of d becomes small, the response time (τ
) becomes small according to the well-known relational expression of ταd8.

Furthermore, the response time (τ) has a proportional relationship (ταη) with the viscosity (η) of the liquid crystal material. That is, a liquid crystal material with a large value of Δn and low viscosity is an extremely important material for manufacturing a liquid crystal display cell with high-speed response.

On the other hand, most of the liquid crystal materials that can be put to practical use are usually prepared by mixing several or more components consisting of a compound that has a nematic phase near room temperature and a compound that has a nematic phase in a temperature range above room temperature. Ru. Many of the above-mentioned mixed liquid crystals currently in practical use are required to have a nematic phase over the entire temperature range of -30°C to +65°C, but the variety of applied products for liquid crystal display cells is With this trend, there is a demand for liquid crystal materials that extend the temperature range of nematic liquid crystals to higher temperatures.

It represents an alkyl group currently used to fabricate fast-response liquid crystal display cells. ), etc.

Although these materials can lower the viscosity of the mixed liquid crystal, they have the disadvantage of lowering Δn and N-I transition temperature.

The compound of formula (■) according to the present invention has improved this drawback, and has a low viscosity, a relatively high Δn, and a high N
-I is a novel nematic liquid crystal compound having a transition temperature. Therefore, by mixing the compound of formula (I) with various parent liquid crystals, a mixed liquid crystal material having a low viscosity, a large Δn, and a high N-I transition temperature can be prepared.

The compound of formula (I) according to the present invention can be produced according to the following production method. R and R' in each of the following formulas (n) to (V) have the same meanings as R and R' in formula (I), respectively.

Step 1 Trans 4-n-alkyl-1-phenylcyclohexane in carbon disulfide or nitrobenzene From the data listed in Table 1, compounds of formula (I) are N-
It can be easily understood that the I transition temperature is high, the nematic temperature range is wide, the viscosity is low, and the Δn is relatively high.

The compound of formula (I) according to the invention is a nematic liquid crystal compound 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 also has strong positive dielectric anisotropy. 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, representative preferred examples that can be used in combination with the compound of formula (1) include, for example, 4,4'-substituted benzoic acid phenyl ester, 4,4'-1! cyclohexanecarboxylic acid phenyl ester, 4.4'- to cyclohexanecarboxylic acid biphenyl ester, 4c4
-M-converted cyclohexane:)! J kyj? 2/I/oxy) benzoic acid 4'-substituted phenyl ester 4(4-[
4(4-substituted cyclohexyl)benzoic acid 4'-substituted phenyl ester, 4(4-substituted cyclohexyl)benzoic acid 4'-substituted cyclohexyl ester, 4.4'-substituted biphenyl,
Examples include 4°4'-substituted phenylcyclohexane, 4,4'-substituted terphenyl, 4,4'-biphenylcyclohexane, and 5-substituted pyrimidine (2<4'-substituted phenyl).

Carbon sulfide 250# in the example! Anhydrous aluminum chloride in 7.24.
DE (o, 1 somoj) was added, and a mixture of trans-4-n-propyl-1-phenylcyclohexane 5039 (0,150 mo/) and propionyl chloride 13.9 g (Q, 150 mol) was added dropwise while heating under reflux.

After heating under reflux for 1 hour, carbon disulfide was distilled off, and the product was added to ice water and stirred at 60°C for 1 hour. After cooling, the product was extracted with toluene, washed with water, dried, and after distilling off the toluene,
Recrystallize and purify with ethanol to obtain the following compound 3t4i012
2 mol) was obtained.

A solution of this compound in anhydrous tetrahydrofuran was added to 4.63 g (0.122 m2) of lithium aluminum hydride.
oj) and 150 d of anhydrous tetrahydro 7 run.

After reacting at room temperature for 2 hours, 9% H (J200m
/ and add 200ml of water, extract the product with toluene,
After washing with water and drying, toluene was distilled off from the extract. The obtained crystals were dissolved in 300 grams of toluene, 0.5 g of potassium hydrogen sulfate was added to this solution, and while water was removed with a decanter, the coco solution was heated under reflux for 1 hour. After the reaction, the reaction solution was washed with water, dried, toluene was distilled off, and the product was purified by recrystallization with ethanol to obtain the following compound 19.2. ! i'(0,0793
1.1.2-1 Lichloroethane 1301R
Bromine 15.5fi (0,08
31 mol> was added dropwise, and after reacting for 1 hour, 1,1.
2-) Lichloroethane was distilled off. The product was dissolved in 200 d of N,N-dimethylformamide and 1.
5-diazabicyclo(5,4,0)undecene-536
, 2 g (0,258 mo/) was added thereto, and the mixture was heated under reflux for 8 hours. After cooling, 500 iJ of 3% hydrochloric acid was added, and the product was extracted with chloroform. After washing with water and drying, chloroform was distilled off, and the product was purified by recrystallization with ethanol to obtain the following compound 10.
．． 8. '7 (0,045mo/) was obtained.

Yield 30.0-% Transition temperature 44℃ (C-+N) 57℃ (N port I) Example 2 The following compound was obtained in the same manner as in Example 1.

Yield rate: 27.5% Transition temperature 42℃ (C-+N) 50℃ (N port I) Example 3 The following compound was obtained in the same manner as in Example 1.

Yield rate: 3tO% Transition temperature 40℃ (C-)N) 64℃ (N mouth ■)

Claims (1)

[Claims] A compound represented by