JP2000204052A - Triphenylene diacetylene compound, and liquid crystal composition containing the compound and liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a triphenylene diacetylene compound having high birefringence, a low melting point, and a high clarifying point, capable of expanding the temperature range of a nematic liquid crystal phase and useful as a component for liquid crystal compositions needed for TN type, STN type and TFT type liquid crystal displays. SOLUTION: A compound of the formula [G1 is CnH2n+11 or OCnH2n+1; (n) is 1-20; G2 is CmH2m+11 or OCmH2m+1; (m) is 1-20; R1-R3 are each H or a 1-3C alkyl], for example, PTP(CH3)TP-36. The compound of the formula is obtained by dissolving a diphenylacetylene compound and 1-(1-ethynyl)-4-hexylbenzene in triethylamine, separately adding triphenyl phosphine, bis(triphenylphosphine) palladium (II) chloride, and copper iodide to the solution under an atmosphere of nitrogen gas, heating and refluxing the obtained solution for a day, cooling the solution, extracting the excessive solvent, washing, concentrating and then drying the product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a triphenyldiacetylene compound, and more particularly to a triphenyldiacetylene compound in which both phenyl groups have different alkyl groups or alkoxyl groups and at least one of three benzene rings has a side substituent ( The present invention relates to a triphenyldiacetylene compound having a side-substituent. This type of triphenyldiacetylene compound is suitable for use as a component of a liquid crystal mixture required for a liquid crystal display.

[0002]

2. Description of the Related Art An STN (super twist nematic) type liquid crystal display has a large optical anisotropy (birefringence Δ
n is 0.15 to 0.20) and a liquid crystal mixture having a low melting point and a high clearing point is required. This is for exhibiting a nematic liquid crystal phase in a wide temperature range. In general, Δn increases as the resonance length of the liquid crystal core structure increases.

[0003] The Republic of the Republic of China No. 312702 discloses a liquid crystal monomer consisting of diacetylene and two benzene rings. Patent No. 288048 discloses a liquid crystal monomer of triphenyldiacetylene having a terminal allyl group.

Have disclosed a triphenyldiacetylene compound having a symmetrical alkoxyl group on the phenyl group at both ends and which can be used as a liquid crystal material (Journ).
nalof Polymer Science: Part A: Polymer Chemistry, V
ol. 28,1101-1126 (1990)). However, although the triphenyldiacetylene compound disclosed by Pugh et al. Has a high birefringence Δn, the melting point is too high because the alkoxyl groups at both ends have a symmetric structure. For this reason, the temperature range of the nematic liquid crystal phase is narrow, and it mainly exhibits a smectic liquid crystal phase. Therefore, TN type (twist nematic), STN
It is not suitable for use as a component of a liquid crystal composition necessary for a liquid crystal display of a type or a thin film transistor (TFT) type liquid crystal display, and has no practical value.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to increase the temperature range of a nematic liquid crystal phase with a high Δn, a low melting point and a high clearing point, and thus to a liquid crystal display. It is an object of the present invention to provide a novel triphenyldiacetylene compound which is suitable for use as one component of a necessary liquid crystal composition. This compound is TN
It is particularly suitable for use as a component of liquid crystal compositions required for liquid crystal displays, STN liquid crystal displays, and TFT liquid crystal displays.

[0006]

That is, the present invention provides a compound represented by the following general formula (I):

[0007]

Embedded image

(Where G ₁ is —C _n H _{2n + 1} or —OC
_n H _{2n + 1} , n is an integer of 1 to 20, and G ₂ is -C _m H _{2m + 1}
Or —OC _m H _{2m + 1} , m is an integer of 1 to 20, and n
And m are not equal, and R ₁ , R ₂ , and R ₃ are each independently H or an alkyl group having 1 to 3 carbon atoms;
_At least one of R ₁ , R ₂ and R ₃ is not H)
It is a triphenyl diacetylene compound represented by these.

Preferably, G ₁ is -C _n H _{2n + 1} , n is an integer of 1 to 10, and G ₂ is -C _m H _{2m + 1} , m is an integer of 1 to 10. Further, n and m are preferably integers of 1 to 6.

Further, G ₁ is —OC _n H _{2n + 1} , n is 1 to
G ₂ is —OC _m H _{2m + 1} , and m is 1 to 10.
It is preferably an integer of 10. Further, n and m are 1
It is preferably an integer of from 6 to 6.

R ₁ and R ₃ are both H, and R ₂
Is preferably an alkyl group having 1 to 3 carbon atoms.
Further, R ₂ is preferably a methyl group.

The liquid crystal composition of the present invention contains 0.01 to 50% by weight of the triphenyldiacetylene compound and 50 to 99.99% by weight of liquid crystal.

Preferably, the content of the triphenyldiacetylene compound is 1 to 30% by weight.

The liquid crystal is of a TN type, STN type, or T
It is preferably an FT type liquid crystal.

The liquid crystal display of the present invention comprises the above liquid crystal composition.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the phenyl groups at both ends have different alkyl groups or alkoxyl groups, respectively.
And a novel triphenyldiacetylene compound in which at least one of the three benzene rings has a side substituent.

The triphenyldiacetylene compound according to the present invention is represented by the following general formula (I).

[0018]

Embedded image

Here, G ₁ is —C _n H _{2n + 1} or —OC _n
H _{2n + 1} , and n is preferably an integer of 1 to 20, particularly an integer of 1 to 10, and particularly preferably an integer of 1 to 6. G ₂ is —C _m H _{2m + 1} or —OC _m H _{2m + 1} ;
Is preferably an integer of 1 to 20, particularly preferably an integer of 1 to 10, and particularly preferably an integer of 1 to 6. R ₁ , R ₂ and R ₃ are each independently H or an alkyl group having 1 to 3 carbon atoms.

A feature of the present invention is that in the substituents G ₁ and G _{2 at} the terminal of the chemical formula (I), n and m are not equal,
Therefore, the phenyl groups at both ends of the chemical formula (I) have different alkyl groups or alkoxyl groups.

A feature of the present invention is also that the chemical formula (I) has the different alkyl or alkoxyl groups G ₁ and G _2, and at least one of the three phenyl groups has a different substituent from the others. That is, R ₁ ,
At least one of R ₂ and R ₃ is not H.

R ₁ , R ₂ and R ₃ are preferably such that R ₁ and R ₃ are both H, R ₂ is an alkyl group having 1 to 3 carbon atoms, and both R ₁ and R ₃ are H. , R ₂ are more preferably methyl groups.

The compound according to the present invention has a high Δn value because it has triphenyldiacetylene as a main structure. Further, since the phenyl groups at both ends of the triphenyldiacetylene compound according to the present invention have different alkyl groups or alkoxyl groups, the lengths of the molecules are different on the left and right sides, thereby reducing the attractive force applied between the ends of the liquid crystal molecules. In addition, the benzene ring at the center of the main chain has a side substituent, which destroys the lateral acting force of the liquid crystal molecules, so that the melting point can be lowered and the temperature range of the nematic liquid crystal phase can be widened.

The liquid crystal composition according to the present invention contains the novel triphenyldiacetylene compound according to the present invention and a liquid crystal. The content of these components in the liquid crystal composition is 0.01 to 50% by weight of the triphenyldiacetylene compound according to the present invention, and 50 to 99.99% by weight of the liquid crystal.
It is. In particular, the content of the triphenyldiacetylene compound according to the present invention is particularly preferably 1 to 30% by weight.

The liquid crystal used in the liquid crystal composition is TN
Type liquid crystal, STN type liquid crystal and TFT type liquid crystal.

The liquid crystal composition according to the present invention can be used for the construction of a liquid crystal display using known techniques. In particular, the ECB (elec
It is applied to STN type liquid crystal displays with trical control birefringence.

[0027]

The following examples further illustrate the method, features and advantages of the present invention, but do not limit the scope of the invention, which is set forth in the following claims. (Examples 1 to 5)
6 for the synthesis process, and FIG. 2 for the synthesis process in Example 7).

Production Example 1 Synthesis of Compounds 1a and 1b Compound 1a (n = 6) (1-hexyl-4-iodobenzene) is taken as an example.

4-hexylaniline (10 g, 56.5)
mmole) was dissolved in 30 ml of THF and cooled to 0-5 ° C., after which 22 ml of strong hydrochloric acid was slowly added. Then, the obtained solution was stirred for 5 to 10 minutes while being cooled in an ice bath, and 23 ml of an aqueous sodium nitrite solution (1 g / 3 m
l) was added quickly. The obtained mixed solution was immediately added to 100 ml of an aqueous solution of potassium iodide (0.56 mol) in an ice bath, and stirred for 2 to 3 hours while maintaining the temperature as it was. The obtained product is diluted with hexane, washed with a saturated aqueous solution of sodium thiosulfate, water, and saturated saline, and then dried over anhydrous magnesium sulfate.
Concentrated. Finally, column separation was performed using silica gel (hexane was used as an eluent) to obtain a colorless and transparent oily liquid 1a in a yield of 94.7%.

In a similar manner, compound 1b (n = 5)
(1-Pentyl-4-iodobenzene) was obtained in a yield of 95%.

In the present invention, experiments were conducted using compounds similar to 1a to 1b. As a result, 1c (n = 4) was 1-bromo-
In 4-butylbenzene, 1d (n = 3) is 1-bromo-
4-propylbenzene, 1e (n = 2) is 1-bromo-4-ethylbenzene, and 1f (n = 1) is 1-bromotoluene. 1c to 1f are all products of Aldrich.

Production Example 2: Synthesis of Compounds 2a to 2f Compound 2a (n = 6) [2-methyl-4- (4-hexylphenyl) -3-butyn-2-ol] is taken as an example.

Compound 1a (14.4 g, 50 mmol
l) and 2-methyl-3-butyn-2-ol (6.3 g, 75 mmol) were dissolved in 150 ml of triethylamine, and triphenylphosphine (1.00 g, 3.75 mmol), bis ( Triphenylphosphine) palladium (II) chloride (0.35 g,
0.5 mmol), and copper iodide (0.38 g, 2 m
mol) were separately added and the resulting mixed solution was heated for 1 day.
Reflux. After cooling, the excess solvent was extracted and diluted with ethyl ether.
After washing with water and saturated saline, it was dried and concentrated through anhydrous magnesium sulfate. Finally, column separation was performed using silica gel (using a mixed solution of ethyl acetate: hexane = 1: 4 as an eluent) to obtain a brown oily liquid 2a in a yield of 9%.
Obtained at 5%.

In a similar manner, compound 2b (n = 5)
[2-Methyl-4- (4-pentylphenyl) -3-butyn-2-ol] was obtained at a yield of 87% of compound 2c (n =
4) [2-Methyl-4- (4-butylphenyl) -3-
Butyn-2-ol] was obtained in a yield of 88% of compound 2d (n
= 3) [2-methyl-4- (4-propylphenyl)-
3-butyn-2-ol] in a yield of 96% with compound 2e
(N = 2) [2-methyl-4- (4-ethylphenyl)
-3-butyn-2-ol] at a yield of ~ 100% and compound 2f (n = 1) [2-methyl-4- (4-methylphenyl) -3-butyn-2-ol] at a yield of ~ Obtained at 100%.

Production Example 3: Synthesis of Compounds 3a to 3f Compound 3a (n = 6) [1- (1-ethynyl) -4-hexylbenzene] is taken as an example.

Compound 2a (7.7 g, 31.6 mmol)
l), and 100 ml of 1,4-dioxane were placed in a round bottom flask, and 1.3 g of potassium hydroxide was added.
The reaction was performed by heating to 100 ° C. in a nitrogen gas environment. Acetone produced by the reaction was collected with a Dean-Stark trap. The obtained product was cooled, added with water, extracted with hexane, dried over anhydrous magnesium sulfate and concentrated. Finally, column separation was performed using silica gel (hexane was used as an eluent) to obtain a colorless and transparent oily liquid 3a in a yield of 97%.

In a similar manner, compound 3b (n = 5)
[1- (1-Ethynyl) -4-pentylbenzene] was obtained at a yield of 83%, and compound 3c (n = 4) [1- (1-ethynyl) -4-butylbenzene] was obtained at a yield of 86%. 3
d (n = 3) [1- (1-ethynyl) -4-propylbenzene] was obtained in a yield of 93% of compound 3e (n = 2) [1-
(1-ethynyl) -4-ethylbenzene] at a yield of 81%
And the compound 3f (n = 1) [1- (1-ethynyl) -4
-Methylbenzene] was obtained with a yield of 78%.

Production Example 4: Synthesis of compounds 4a and 4b Synthesis of compound 4a (methyl group occupies ortho position): o-Toluidine (20 g, 0.187 mol) was placed in a round bottom flask, and iodine (47.5 g) was added. , 0.187m
ol), calcium carbonate (23.3 g, 0.233 mo)
l), and 100 ml of water were added separately. The obtained solution was stirred at room temperature for 1 hour, further heated to 60 to 70 ° C., stirred for 5 minutes, cooled, added with water, and extracted with ethyl ether. The obtained organic layer was dried and concentrated with anhydrous magnesium sulfate, and finally recrystallized with a 50% aqueous ethanol solution. As a result, a white solid crystal 4a was obtained in a yield of 83%.

Synthesis of compound 4b (methyl group occupies meta position): o-toluidine (1 g, 9.3 mmol)
l), sodium bicarbonate (1.2 g, 14.3 mmol)
l) and 8 ml of water into a 50 ml round bottom flask and after cooling, add iodine (2 g, 7.9 mmol) to 2
Added in ~ 3 portions. After stirring the obtained solution for 1 hour while maintaining the temperature as it was, water was added and extracted with ethyl ether. The obtained organic layer is washed with a saturated aqueous solution of sodium thiosulfate, water, and saturated saline, dried and concentrated with anhydrous magnesium sulfate, and finally, a mixed solution of column separation on silica gel (ethyl acetate: hexane = 1: 4). Was used as an eluent.) As a result, a transparent light purple oily liquid 4b was obtained in a yield of 75.2%.

Preparation Example 5: Synthesis of Compounds 5a to 5c The synthesis of Compound 5a (n = 3, methyl group occupies the ortho position) is taken as an example.

First, compound 4a (8.38 g, 36 mm
ol), and compound 3d (6.48 g, 45 mmol)
l) was dissolved in 100 ml of triethylamine and placed in a round-bottomed flask.
7 g, 2.7 mmol), bis (triphenylphosphine) palladium (II) chloride (0.25 g, 0.36 mmol
l), and copper iodide (0.25 g, 1.3 mmol)
Were added separately and heated and refluxed for one day. After cooling, the excess solvent was extracted and diluted with ethyl ether. Then, it is washed with a saturated aqueous solution of ammonium chloride, water, and saturated saline, dried and concentrated over anhydrous magnesium sulfate, and finally separated by column on silica gel (ethyl acetate: hexane = 1: 4).
Was used as an eluent) to give a brown solid 5a in a yield of 95%.

In a similar manner, compound 5b (n = 1,
The compound 5c (n = 2, where the methyl group occupies the meta position) was obtained with a yield of 76% for the methyl group occupying the ortho position and a yield of 76%.

Production Example 6: Synthesis of Compounds 6a to 6c The synthesis of compound 6a (n = 3, methyl group occupies the ortho position) is taken as an example.

Compound 5a (7.25 g, 29 mmol)
Was dissolved in 15 ml of THF, and after cooling, the solution was added to an ice nitrite solution prepared from 16 ml of strong hydrochloric acid and 17.5 ml of sodium nitrite, and the resulting mixture was further frozen with a 6M aqueous potassium iodide solution ( 50 ml). Then, the mixture was stirred for 2 to 3 hours while maintaining the temperature as it was, a saturated aqueous solution of sodium thiosulfate was added, and the mixture was extracted with hexane. Then, the obtained organic layer was washed with water and saturated saline, dried and concentrated over anhydrous magnesium sulfate, and finally subjected to column separation on silica gel (using hexane as an eluent) to obtain white solid crystals 6a. The yield is 60
%.

In a similar manner, compound 6b (n = 1,
The compound 6c (n = 2, where the methyl group occupies the meta position) was obtained with a yield of 54% for the methyl group occupying the ortho position and a yield of 54%.

Example 1 Triphenyldiacetylene Compound
Things _{[PTP (CH 3) TP-} nm] Synthesis of (reference to the flow chart of FIG. 2) compound _{PTP (CH 3) TP-36} (n = 3, m = 6)
Take the synthesis of

First, compound 6a (3 g, 8.3 mmol)
l) and compound 3a (2.8 g, 15 mmol) in 3
Dissolved in 5 ml of triethylamine and placed in a round bottom flask. Then, triphenyl phosphorus (0.
17g, 0.65mmol), bis (triphenylphosphine) palladium (II) chloride (60mg, 0.083m
mol), and copper iodide (60 mg, 0.31 mmol)
l) were added separately and the resulting solution was heated and refluxed for one day. After cooling, extract the excess solvent and dilute with hexane,
After further washing with a saturated aqueous solution of ammonium chloride, water, and saturated saline, drying and concentration over anhydrous magnesium sulfate, and finally column separation on silica gel (using hexane as an eluent), white solid crystals [PTP
(CH ₃ ) TP-36] was obtained in a yield of 21.5%.

The yields and spectral values of a series of triphenyldiacetylene compounds obtained by similar methods are shown in Tables 1 and 2.
It is shown in FIG. The melting point (Tm), clearing point (Tc), and enthalpy (ΔH) were measured with a differential scanning calorimeter, and the results are shown in Table 5.

[0049]

[Table 1]

[0050]

[Table 2]

[0051]

[Table 3]

[0052]

[Table 4]

[0053]

[Table 5]

FIG. 3 shows the phase transition temperatures (Tm and Tc) of the PTP (CH ₃ ) TP-nm series compound (n = 1) plotted against m. In the figure, the section above Tc is section I (isotropic, isotropic section), the section between Tc and Tm is section N (nematic, nematic section), and the section below Tm is section K (solid phase section). .

FIG. 4 shows the phase transition temperatures (Tm and Tc) of the PTP (CH ₃ ) TP-nm series compound (n = 3) plotted against m. PTP (CH ₃₎ TP-
Phase transition temperature (Tm and Tc) of nm series compound (m = 2)
Is plotted against n in FIG.

As can be seen from FIGS. 3 to 5, as the asymmetry of the alkyl groups of the phenyl groups at both ends becomes more remarkable,
It can be seen that the range in which the nematic liquid crystal phase is exhibited (that is, the N section) is increased.

Example 2 E63 liquid crystal (composed of a cyano-biphenyl mixture) manufactured by Merck was added to the 20% by weight of P obtained in Example 1.
TP (CH ₃ ) TP-63 (n = 6, m = 3) was added, and the birefringence Δn under different wavelengths was measured. The results are shown in FIG. From the figure, it can be seen that when the triphenyldiacetylene compound according to the present invention is added, Δn
It can be seen that the value can be increased. Further, the triphenyldiacetylene compound according to the present invention has excellent compatibility with commercially available liquid crystals.

Although the preferred embodiments have been disclosed above, they are not intended to limit the scope of the present invention in any way, and anyone skilled in the art will be able to provide the same without departing from the spirit and scope of the present invention. Various variations and additions should be made, and accordingly, the protection scope of the present invention is based on the contents specified in the claims.

[0059]

From the above, it can be seen that the triphenyldiacetylene compound according to the present invention has a wide temperature range of a nematic liquid crystal phase and can be used as one component of a liquid crystal composition required for a liquid crystal display. The compound is, in particular,
It is suitable for use as a component of a liquid crystal composition required for TN type, STN type, and TFT type liquid crystal displays.

The triphenyldiacetylene compound according to the present invention can be added to all kinds of liquid crystals and used as one component in a liquid crystal composition. The liquid crystal as used herein refers to a mixture composed of multiple components having a generally known liquid crystal phase.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a first half of a process of synthesizing a triphenyldiacetylene compound according to the present invention.

FIG. 2 is a flowchart showing a latter half of a process for synthesizing a triphenyldiacetylene compound according to the present invention.

FIG. 3 shows PTP (CH ₃ ) TP-nm series compounds (n =
2 is a graph showing the relationship between m and the phase transition temperature of 1).

FIG. 4. PTP (CH ₃ ) TP-nm series compound (n =
3 is a graph showing the relationship between m and the phase transition temperature of 3).

FIG. 5: PTP (CH ₃ ) TP-nm series compound (m =
3 is a graph showing the relationship between the phase transition temperature and n in 2).

FIG. 6 is a graph showing the effect of raising the Δn value of the triphenyldiacetylene compound obtained in Example 7 on the E63 liquid crystal.

Claims (11)

[Claims] 1. The following general formula (I): (Wherein, G ₁ is -C _n H _{2n + 1} or -OC _n H _{2n +} 1, _n
Is an integer of 1 to 20, and G ₂ is —C _m H _{2m + 1} or —O
C _m H _{2m + 1} , m is an integer of 1 to 20, n and m are not equal, and R ₁ , R ₂ , and R ₃ are each independently H or an alkyl group having 1 to 3 carbon atoms. And at least one of R ₁ , R ₂ and R ₃ is not H). 2. The method of claim 2, wherein₁Is -C_nH_{2n + 1}, N is 1 to 10
An integer; _TwoIs -C_mH_{2m + 1}, M is 1 to 10
3. The triphenyldiacetylene compound according to claim 1,
object. 3. The triphenyldiacetylene compound according to claim 2, wherein n and m are integers of 1 to 6. 4. The method according to claim 1, wherein G ₁ is —OC _n H _{2n + 1} , and n is 1 to 10.
Wherein G ₂ is —OC _m H _{2m + 1} , and m is 1 to 10
The triphenyldiacetylene compound according to claim 1, which is an integer of the following. 5. The triphenyldiacetylene compound according to claim 4, wherein n and m are integers of 1 to 6. 6. The method according to claim 6, wherein R ₁ and R ₃ are both H.
The triphenyldiacetylene compound according to claim 1, wherein ₂ is an alkyl group having 1 to 3 carbon atoms. 7. The triphenyldiacetylene compound according to claim 6, wherein said R ₂ is a methyl group. 8. The composition according to claim 1, wherein the triphenyldiacetylene compound is present in an amount of 0.01 to 50% by weight and the liquid crystal is present in an amount of 50 to 50%.
A liquid crystal composition containing 99.99% by weight. 9. The liquid crystal composition according to claim 8, wherein the content of the triphenyldiacetylene compound is 1 to 30% by weight. 10. The liquid crystal composition according to claim 8, wherein the liquid crystal is a TN type, STN type, or TFT type liquid crystal. 11. A liquid crystal display comprising the liquid crystal composition according to claim 8.