JP2005104853A - U-shaped compound and liquid crystal composition containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compound capable of lowering drive voltage when added to a nematic liquid crystal material. <P>SOLUTION: The U-shaped compound is represented by formula (1) or formula (2). In formula (2) X is a hard group such as benzene and cyclohexane; A<SP>1</SP>, A<SP>2</SP>, B<SP>1</SP>, and B<SP>2</SP>are each independently a bonding group such as a single bond, an ether bond, or an ester bond; m and n are each an integer of ≥1; p and q are each independently an integer of 0 or 1; D and E are each independently a substituent on a benzene ring and the substitution position and number are not limited. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

    The present invention relates to a U-shaped compound and a liquid crystal composition containing the same, and more particularly to a novel U-shaped liquid crystal compound for reducing a driving voltage in a nematic liquid crystal material or a chiral nematic liquid crystal material for display and the same. The present invention relates to a liquid crystal composition containing The material of the present invention is extremely effective in producing a liquid crystal composition that constitutes an optoelectronic-related element such as an optical printer head or a light valve for a display such as a liquid crystal television.

  The problem with the current liquid crystal display is to improve the high-speed response that can withstand moving image display. There are mainly development of drive mode (Akira Nakamura “Liquid Crystal” 2001, 5.253) and development of liquid crystal materials (Akihiro Kubo “Liquid Crystal” 2001, 5.327). In terms of the latter material development, in order to shorten the response time, (1) reduce the viscosity of the liquid crystal material, (2) increase the dielectric anisotropy (Δε) of the liquid crystal material, (3 It is effective to reduce the cell thickness, that is, to increase the refractive index anisotropy (Δn) of the liquid crystal material.

"Liquid Crystal" (Japan Liquid Crystal Society) 2001, 5.253, Author: Atsushi Nakamura "Liquid Crystal" (Japan Liquid Crystal Society) 2001, 5.327, Author: Akihiro Kubo

However, a compound having a large Δε or Δn generally has a high viscosity. In order to increase Δε, it is important to adjust the polarity of the molecule. However, substituents having a large polarity such as —CN and —NO ₂ can easily take in impurity ions, and as a result, the voltage holding ratio (VHR) Is not suitable for TFT driving.

  A compound represented by the following formula (Formula 1) is known to have a driving voltage lowering effect in a conventional liquid crystal material for liquid crystal displays. However, since it contains a cyano group, it is not suitable for TFT driving as described above.

By the way, with respect to a molecule in which two molecules are connected in a U-shape and formed into a U-shape, that is, a U-shaped liquid crystal compound, conventionally, there are the following research examples.
D. Vorlander & A. Apel Chem. Ber. 1932, 65.1101
M.M. Matsuzaki & Y. Matsunaga Liq. Cryst. 1993, 14.105
T.A. Kato et al Chem. Letl. , 1992.265
G. S. Attard & A. G. Douglas Liq. Cryst, 1997.22.349
One of the present inventors, Yoshizawa et al. Has developed a new molecular design from the viewpoint of controlling the molecular motion of liquid crystal (Atsushi Yoshizawa “Liquid Crystal 2001.5.224”), and developed a new U-shaped compound for liquid crystal. Synthesized and reported that the order of the nematic phase of this compound is different from the conventional one (Chem. Comm., 2002.02060).
However, these reports all relate to the phase transition behavior of the liquid crystal and do not describe the influence on the electro-optical effect.

  The object of the present invention is to solve the problem in light of the state of the prior art, and to reduce the driving voltage by adding to a nematic liquid crystal material or a chiral nematic liquid crystal material even if the polarity as one molecule is small. And a liquid crystal composition containing the same.

  In the course of studying the above problems, when the crystal structure analysis was performed on the compound represented by the formula (III), the present inventor found that the adjacent two molecules faced in the same direction. . Based on this result, a molecule in which two molecules having a dipole moment were connected in a U shape as shown in the conceptual diagram of FIG. 1 was designed. That is, by making a U-shaped compound by incorporating a mesogen having fluorine, trifluoromethyl group, trifluoromethoxy group or the like as a substituent, and adding this to a nematic liquid crystal composition or the like, The present invention has been achieved in which the drive voltage can be lowered without affecting the physical properties. That is, the invention claimed in the present application is as follows.

(1) A U-shaped compound represented by the following general formula (Formula 2).

〔本項において式中、Ｘ_０は二つのメソゲン基をつなげるコネクターで、ベンゼン、シクロヘキサン等の堅い基である。Ａ_１、Ａ_２、Ｃ_１、Ｃ_２はそれぞれ独立した単結合、エーテル結合、エステル結合、またはアミド結合等の結合基である。Ｂ_１、Ｂ_２はそれぞれ独立した直鎖または分枝を有する脂肪族化合物スペーサーである。Ｙ_１、Ｙ_２はそれぞれ独立したビフェニル、フェニル、安息香酸エステル、シクロヘキサン、ベンゼン、フェニルシクロヘキサン、ターフェニル、フェニルピリミジン等の堅い基である。Ｚ_１、Ｚ_２は少なくともいずれか一方が、それぞれ独立した電子吸引基または電子供与基である。〕
なお、上述のとおりＹ_１、Ｙ_２は液晶形成能の有無は限定されないが、これを特に、液晶形成能を有するものとすることもできる。
（２）下記一般式（化３）で表されるＵ字型化合物。〔本項目において式中、Ｘはベンゼン、シクロヘキサン等の堅い基である。Ａ^１、Ａ^２、Ｂ^１、Ｂ^２はそれぞれ独立した単結合、エーテル結合、エステル結合またはアミド結合等の結合基である。ｍ、ｎはそれぞれ独立した１以上の整数である。ｐ、ｑはそれぞれ独立した０または１のいずれかの整数である。Ｄ、Ｅはそれぞれ独立したベンゼン環の置換基であり、置換位置および数は限定されない。〕

[In this formula, X ₀ is a connector that connects two mesogenic groups, and is a rigid group such as benzene or cyclohexane. A ₁ , A ₂ , C ₁ , and C ₂ are each independently a bonding group such as a single bond, an ether bond, an ester bond, or an amide bond. B ₁ and B ₂ are each an aliphatic compound spacer having an independent straight chain or branch. Y ₁ and Y ₂ are each a rigid group such as biphenyl, phenyl, benzoate ester, cyclohexane, benzene, phenylcyclohexane, terphenyl, and phenylpyrimidine. At least one of Z ₁ and Z ₂ is an independent electron withdrawing group or electron donating group. ]
As described above, the presence or absence of the liquid crystal forming ability of Y ₁ and Y ₂ is not limited. However, this may have a liquid crystal forming ability.
(2) A U-shaped compound represented by the following general formula (Formula 3). [In this item, in the formula, X is a rigid group such as benzene or cyclohexane. A ¹ , A ² , B ¹ , and B ² are each independently a bonding group such as a single bond, an ether bond, an ester bond, or an amide bond. m and n are each independently an integer of 1 or more. p and q are each independently an integer of 0 or 1. D and E are independent benzene ring substituents, and the substitution position and number are not limited. ]

（３） 下記一般式（化４）で表される化合物。〔本項目において式中、ｍ、ｎはそれぞれ独立した３〜１５の整数、ｐ、ｑはそれぞれ独立した０または１のいずれかの整数、Ｘ、Ｙはそれぞれ独立したＨ、Ｆ、ＣＦ_３、ＯＣＦ_３、ＣＦ_２Ｈ、ＣＦＨ_２、ＯＣＦ_２Ｈ、ＯＣＦＨ_２等のベンゼン環上の置換基であり、その置換位置および数は限定されない。〕

(3) A compound represented by the following general formula (Formula 4). [In this item, m and n are each independently an integer of 3 to 15, p and q are each independently an integer of 0 or 1, X and Y are each independently H, F, CF ₃ , It is a substituent on the benzene ring such as OCF ₃ , CF ₂ H, CFH ₂ , OCF ₂ H, OCFH ₂ , and the substitution position and number are not limited. ]

（４） （１）ないし（３）のいずれかに記載の化合物を含有させたことを特徴とする、液晶組成物。
（５） ネマチック液晶組成物もしくはキラルネマチック液晶組成物に（１）ないし（３）のいずれかに記載の化合物を含有させたことを特徴とする、ネマチック液晶組成物もしくはキラルネマチック液晶組成物。

(4) A liquid crystal composition comprising the compound according to any one of (1) to (3).
(5) A nematic liquid crystal composition or a chiral nematic liquid crystal composition, wherein the nematic liquid crystal composition or the chiral nematic liquid crystal composition contains the compound according to any one of (1) to (3).

In addition to the claimed inventions, the following inventions are also disclosed by the present application.
(6) A U-shaped compound represented by the following general formula (Formula 5). [Wherein, m and n are each independently an integer of 3 to 15. p and q are each independently an integer of 0 or 1. R ¹ , R ² , R ³ and R ⁴ are each independently H or a substituent of the benzene ring. ]

(7) In the above general formula (Formula 5), R ¹ , R ² , R ³ , and R ⁴ are each independently H, F, CF ₃ , OCF ₃ , CF ₂ H, CFH ₂ , OCF ₂ H, OCHF _2. The U-shaped compound according to (6), which is a substituent on a benzene ring such as CN.

(8) The U-shaped compound according to (7), wherein at least one of R ^{2 and} R ⁴ is F in the general formula (Formula 5).

(9) A liquid crystal composition comprising the U-shaped compound according to any one of (1) to (8).
(10) The host material of the liquid crystal composition comprising at least one of the following compounds (Chemical formula 6) or all of them, according to any one of (1) to (9): A liquid crystal composition comprising a U-shaped compound.

(11) The U-shaped compound according to any one of (1) to (8) is added to 75 to 99 parts by weight of the host material so that the total amount becomes 100 parts by weight. The liquid crystal composition according to (10).
(12) The U-shaped compound according to any one of (1) to (8) is added to 85 to 95 parts by weight of the host material so that the total amount becomes 100 parts by weight. The liquid crystal composition according to (10).

  Since the U-shaped compound of the present invention is constituted as described above, a small amount of the U-shaped compound is added to a nematic or chiral nematic liquid crystal composition, so that the driving voltage particularly in a display nematic liquid crystal material or chiral nematic liquid crystal material is remarkably increased. Can be lowered. And according to the liquid crystal composition containing the U-shaped compound of the present invention, a low power consumption liquid crystal display element can be constructed and manufactured.

That is, the structure of the U-shaped compound of the present invention is characterized in that two molecules having a dipole moment are connected by a rigid group such as benzene and cyclohexane to form a U-shape. In the above formula (Formula 3), p and q are each independently an integer of 0 or 1, and therefore, a portion connected from B ¹ or B ^{2 in the} terminal direction is a phenyl group or a biphenyl group.

  The carbon number (m, n) of the alkyl group in the general formula (Chemical Formula 3) or (Chemical Formula 4) may slightly affect the temperature range of the region taking the liquid crystal phase, but there is no problem with the liquid crystal composition. Can be used. Therefore, the carbon number (m, n) is not particularly limited and can take any value as long as it is an integer of 1 or more. However, in consideration of the availability of raw materials, cost, etc., m and n are preferably integers in the range of 3 to 15.

  Some of the compounds represented by the above general formulas (Chemical Formula 3) or (Chemical Formula 4) of the present invention may be used alone or have a liquid crystal phase. In this case, they may be used alone as a liquid crystal material. However, in particular, by adding the compound of the present invention to a liquid crystal composition exhibiting a nematic phase or a chiral nematic phase, it becomes possible to reorient the liquid crystal molecules at a lower voltage, and a nematic liquid crystal composition having a low driving voltage is obtained. be able to. In this case, the addition amount of the compound represented by either the above general formula (Chemical Formula 3) or (Chemical Formula 4) varies depending on the type of the nematic liquid crystal composition to be added and the type of the compound of the present invention to be added. There is no particular limitation. However, appropriately selecting from the range of 1 to 25% by weight to obtain the added amount brings about a preferable result.

  By using a liquid crystal composition comprising the compound exemplified in the above formula (Formula 6) as a host material and containing a small amount of the compound of the present invention as described above, a novel nematic or chiral nematic liquid crystal composition can be obtained. The liquid crystal composition that can be used as the host material is not limited to the example of the above formula (Formula 6).

Specific examples of the U-shaped compound of the present invention include the following (Chemical Formula 7 (a) to Chemical Formula 12).

Among the compounds represented by the above general formula, some representative compounds show their physicochemical properties.
1- {6- (3,4-difluorophenyloxy) hexyloxy} -2- {6- (4-fluorobiphenyl-4′-yloxy) hexyloxy} benzene (Chemical Formula 13 below)

¹ H-NMR (270 MHz, in CDCl ₃ , TMS standard) δ 7.51 to 7.41 (4H, m), 7.12 to 6.87 (9H, m), 6.71 to 6.63 (1H, m), 6.58 to 6.51 (1H, m), 4.03 to 3.97 (4H, q), 3.88 (4H, t), 1.85 to 1.51 (17H, m)
IR (cm ⁻¹ ); 2944, 1606, 1516, 1493

  1,2-bis {6- (4-fluorobiphenyl-4'-yloxy) hexyloxy} benzene (Chemical Formula 14 below)

¹ H-NMR (ppm) δ 7.50 to 7.40 (8H, m), 7.11 to 7.02 (4H, m), 6.95 to 6.89 (8H, m), 4.04 to 3.95 (8H, m), 1.90 to 1.78 (8H, m), 1.62 to 1.52 (8H, m)
IR (cm ⁻¹ ); 1510, 2944, 1610

  1- {6- (4-trifluoromethylphenyloxy) hexyloxy} -2- {6- (4-fluorobiphenyl-4'-yloxy) hexyloxy} benzene (Formula 15 below)

¹ H-NMR (ppm) δ 7.52 to 7.40 (6H, m), 7.12 to 7.04 (2H, m), 6.95 to 6.88 (8H, m), 4.05 3.95 (8H, m), 1.89 to 1.79 (m) and 1.58 to 1.50 (m) combined to 16H
IR (cm ⁻¹ ); 2944, 1610, 1505, 1321

  1- {6- (4-fluorophenyloxy) hexyloxy} -2- {6- (4-fluorobiphenyl-4'-yloxy) hexyloxy} benzene (Formula 16)

¹ H-NMR (ppm) δ 7.52 to 7.40 (4H, m), 7.13 to 7.04 (2H, m), 6.98 to 6.88 (10H, m), 4.04 to 3.87 (8H, m), 1.87 to 1.73 (m) and 1.59 to 1.45 (m) combined to 16H
IR (cm ⁻¹ ); 2944, 1501, 1252, 828

  1- {6- (4-trifluoromethoxyphenyloxy) hexyloxy} -2- {6- (4-fluorobiphenyl-4'-yloxy) hexyloxy} benzene (formula 17 below)

¹ H-NMR (ppm) δ 7.51 to 7.40 (4H, m), 7.12 to 7.04 (4H, m), 6.97 to 6.80 (8H, m), 4.03 to 3.89 (8H, m), 1.87 to 1.74 (m) and 1.62 to 1.52 (m) combined to 16H
IR (cm ⁻¹ ); 2945, 1507, 1245, 826

  1,2-bis {6- (4-fluorophenyl-4'-yloxy) hexyloxy} benzene (Chemical Formula 18 below)

¹ H-NMR (ppm) δ 6.98-6.77 (12H, m), 4.00 (4H, m), 3.90 (4H, m), 1.81 (8H, m), 1.60 ~ 1.59 (8H, m)
IR (cm ⁻¹ ); 2937, 1594, 1507, 824, 738

  1,2-bis {6- (4-cyanobiphenyl-4'-yloxy) hexyloxy} benzene (the following chemical formula 19)

¹ H-NMR (ppm) δ 7.68 to 7.58 (8H, m), 7.52 to 7.46 (4H, m), 699 to 6.93 (4H, m), 6.89 to 6.87 (4H, m), 4.04-3.97 (8H, m), 1.88-1.78 (8H, m), 1.63-1.53 (8H, m)
IR (cm ⁻¹ ); 2940, 2225, 1601, 1504, 1251, 825

  1- {6- (4-Fluorobiphenyl-4'-yloxy) hexyloxy} -2- {3- (4-fluorophenyloxy) propyloxy} benzene (Chemical Formula 20 below)

¹ H-NMR δ 7.46 to 6.75 (12H, m), 6.71 to 6.66 (4H, m), 4.04 to 3.87 (8H, m), 2.13 to 1.29 (10H, m)
IR (cm ⁻¹ ); 2934, 1507, 1257, 1504, 823

  Next, an example of a basic synthesis scheme for obtaining an asymmetric catechol derivative which is a skeleton of the U-shaped compound of the present invention is shown below (Chemical Formula 21).

By Williamson synthesis, it is synthesized through a three-step reaction. All three stages are reacted in the presence of potassium carbonate in cyclohexane. First, catechol is alkylated using nucleophilic substitution reaction with one side of dibromohexane in the presence of potassium carbonate. To react only on one side, dibromohexane is used in excess. In the second stage reaction, only one of the two bromoalkyl groups bonded to catechol is biphenylated, so the temperature is set so as not to raise the heating temperature too much. In the third stage reaction, the remaining bromoalkyl group is similarly reacted to synthesize the target compound. The structure of the synthesized compound is identified by ¹ H-NMR.

Hereinafter, the present invention will be described in more detail with reference to examples.
<Example 1>
Synthesis of 1- {6- (3,4-difluorophenyloxy) hexyloxy} -2- {6- (4-fluorobiphenyl-4′-yloxy) hexyloxy} benzene target compound 1650 mg (15 mmol) of catechol and 1, 6.95 g (45 mmol) of 6-dibromohexane was dissolved in cyclohexanone (30 ml), 4140 mg (30 mmol) of potassium carbonate was added, and the mixture was stirred while heating (135 ° C. 0.5 hour, 140 ° C. 5.5 hour). The solid was filtered off from the reaction mixture, and the filtrate was concentrated. The obtained mixture of liquid and solid was subjected to column chromatography using a mixed solvent of methylene chloride / hexane (7/3) as a developing solvent, and the yield of intermediate 1,2-bis- (6-bromohexyloxy) benzene was 3470 mg ( 8.0 mmol, 53% yield).

  1,30-mg (7.0 mmol) of 1,2-bis- (6-bromohexyloxy) benzene and 2000 mg of 4-fluoro-4'-hydroxybiphenyl were dissolved in cyclohexanone (25 ml), and 970 mg (7.0 mmol) of potassium carbonate was added. The mixture was stirred while heating (70 ° C. 5.5 hours, 80 ° C. 0.5 hours). The solid was filtered off from the reaction mixture, and the filtrate was concentrated. The obtained solid was subjected to column chromatography using a mixed solvent of methylene chloride / hexane (7/3) as a developing solvent to obtain an intermediate yield of 270 mg (0.5 mmol, yield 7.2%).

  250 mg (0.48 mmol) of the above intermediate and 94 mg (0.72 mmol) of 3,4-difluorophenol were dissolved in cyclohexanone (10 ml), and 99.3 mg (0.72 mmol) of potassium carbonate was added and stirred while heating. (90 ° C., 6 hours). The solid was filtered off from the reaction mixture, and the filtrate was concentrated. The obtained solid was subjected to column chromatography using a mixed solvent of methylene chloride / hexane (7/3) as a developing solvent to obtain 102 mg (0.17 mmol, 36.3% yield) of the target compound.

Measurement of physical properties The phase transition temperature of the synthesized compound was measured using a polarizing microscope. Moreover, the phase transition enthalpy and mp were calculated | required using the differential scanning calorimeter (Seiko Instruments Inc. DSC6200).
During cooling, the liquid became a nematic phase at 11.1 ° C. (1.73 kJmol ⁻¹ ) from the isotropic liquid (Iso.Liq), and did not crystallize even when cooled to −50 ° C. The mp during heating was 53.7 ° C. (41.1 kJmol ⁻¹ ).

Voltage dependence of light transmittance The voltage dependence of light transmittance was investigated. For the measurement, a polarizing microscope (NIKONOPTTIHOTO-POL) equipped with a METTLER FP82, an electro-optical property measuring device (digital storage oscilloscope) (HITACHI DIGITAL STORE OSCILLOSCOPE VC-6050), a high-speed power amplifier (NF) ELECTRONIC INSTRUMENTS function 4005 A generator (NF ELECTRONIC FG-141) was used.

  In order to investigate the effect of the compound of the present invention as an additive, a liquid crystal composition represented by the following formula (Formula 22) was prepared and used as a host material. This is designated as host liquid crystal composition A. The phase transition temperature of A became a nematic phase at IsoLiq 48.9 ° C and crystallized at -56 ° C.

  10 parts by weight of the compound of the present invention, which is a measurement object, was added to 90 parts by weight of Host A and injected into an ITO cell (cell thickness 4.3 μm) that had been subjected to polyimide rubbing treatment. An AC voltage having a frequency of 1 Hz was applied at 25 ° C., and the voltage dependency of the transmittance at that time was measured. The standard for measurement was that the moment when the molecules were rising was 100% transmittance, and the state where the molecules were completely up was 0% transmittance. The measurement was repeated several times, and the average value was calculated.

  The voltages when the light transmittance of the host A changed by 10% and 50% were 10V and 23V, respectively. On the other hand, in the case of adding 10 parts by weight of the compound of the present invention, the voltages when the transmittance change was changed by 10% and 50% were 5.6 V and 13.6 V, respectively. Therefore, it was clearly shown that the compound of the present invention is a very useful compound in reducing the driving voltage.

<Comparative Example 1>
10 parts by weight of 4-fluoro-4′-hexyloxybiphenyl (Chemical Formula 23) was added to 90 parts by weight of Host A, and the voltage dependency of the light transmittance was examined. A graph of the measurement results of Example 1 and Comparative Example 1 is shown in FIG.
As is clear from FIG. 2, the compound of the present invention of Example 1 showed a remarkable voltage reduction effect as compared with the compound of Comparative Example 1.

<Example 2>
Synthesis of 1,2-bis {6- (4-fluorobiphenyl-4′-yloxy) hexyloxy} benzene target compound, measurement of physical properties, and measurement of voltage dependence of light transmittance are in accordance with the method of Example 1. As the reaction starting materials, 1,2-bis (6-bromohexyloxy) benzene and 4-fluoro-4′-hydroxybiphenyl were used. These were reacted in the presence of potassium carbonate using cyclohexanone as a solvent to obtain the target compound in a third stage yield of 31%. The phase transition temperature became a nematic phase at IsoLiq 89.6 ° C. and crystallized at 74 ° C. The mp was 109 ° C.

<Example 3>
1- {6- (3,4-trifluoromethylphenyloxy) hexyloxy} -2- {6- (4-fluorobiphenyl-4′-yloxy) hexyloxy} benzene In the same manner as in Example 1, 1- (6-Bromohexyloxy) -2- {6- (4-fluorobiphenyl-4′-yloxy) hexyloxy} benzene was synthesized by using 4-trifluoromethylphenol and cyclohexanone as a solvent for carbonation. By reacting in the presence of potassium, the target compound was obtained in a yield of 74.1% in the third stage. The phase transition temperature became a nematic phase at IsoLiq of 24.6 ° C. and did not crystallize even when cooled to −30 ° C. The mp was 82.5 ° C.

  10 parts by weight of the compound of this example was mixed with 90 parts by weight of the host A described in Example 1 to prepare a liquid crystal composition. According to the method described in Example 1, the voltage dependence of transmittance was measured. As a result, the voltages when the transmittance change was changed by 10% and 50% were 7.3 V and 11.4 V, respectively. Therefore, it was clearly shown that the compound of the present invention is a very useful compound in reducing the driving voltage.

<Example 4>
1- {6- (4-Fluorophenyloxy) hexyloxy} -2- {6- (4-fluorobiphenyl-4′-yloxy) hexyloxy} benzene In the same manner as in Example 1, intermediate 1- ( 6-Bromohexyloxy) -2- {6- (4-fluorobiphenyl-4'-yloxy) hexyloxy} benzene is synthesized and reacted with 4-fluorophenol in the presence of potassium carbonate using cyclohexane as a solvent. As a result, the target compound was obtained in a yield of 70.0% in the third stage. The phase transition temperature became a nematic phase at IsoLiq of 25.0 ° C. The mp was 76.0 ° C.

  10 parts by weight of the compound of this example was mixed with 90 parts by weight of the host A described in Example 1 to prepare a liquid crystal composition. According to the method described in Example 1, the voltage dependence of transmittance was measured. As a result, the voltages when the transmittance change changed by 10% and 50% were 7.3 V and 10.5 V, respectively. Therefore, it was clearly shown that the compound of the present invention is a very useful compound in reducing the driving voltage.

<Example 5>
1- {6- (4-trifluoromethoxyphenyloxy) hexyloxy} -2- {6- (4-fluorobiphenyl-4′-yloxy) hexyloxy} benzene In the same manner as in Example 1, intermediate 1 -(6-Bromohexyloxy) -2- {6- (4-fluorobiphenyl-4'-yloxy) hexyloxy} benzene was synthesized with 4-trifluoromethoxyphenol and potassium carbonate in the presence of cyclohexanone as a solvent. By reacting under the above conditions, the target compound was obtained with a yield of 70.0% in the third stage. The phase transition temperature became a nematic phase at IsoLiq 27.0 ° C. The mp was 69.0 ° C.

  10 parts by weight of the compound of this example was mixed with 90 parts by weight of the host A described in Example 1 to prepare a liquid crystal composition. According to the method described in Example 1, the voltage dependence of transmittance was measured. As a result, the voltages when the transmittance change was changed by 10% and 50% were 7.6 V and 11.7 V, respectively. Therefore, it was clearly shown that the compound of the present invention is a very useful compound in reducing the driving voltage.

<Example 6>
Synthesis of 1,2-bis {6- (4-fluorophenyl-4′-yloxy) hexyloxy} benzene target compound, measurement of physical properties, and measurement of voltage dependence of light transmittance are in accordance with the method of Example 1. As the reaction starting materials, 1,2-bis (6-bromohexyloxy) benzene and 4-fluoro-4′-hydroxybiphenyl were used. These were reacted in the presence of potassium carbonate using cyclohexanone as a solvent to obtain the target compound in a third stage yield of 31%. The phase transition temperature became a nematic phase at IsoLiq89.6 ° C. During cooling, no crystallization occurred even at -50 ° C or lower. The mp was 37.9 ° C.

  10 parts by weight of the compound of this example was mixed with 90 parts by weight of the host A described in Example 1 to prepare a liquid crystal composition. According to the method described in Example 1, the voltage dependence of transmittance was measured. As a result, the voltage when the transmittance change was changed by 50% was 13.3V. Therefore, it was shown that the compound of the present invention is a very useful compound in reducing the driving voltage.

<Example 7>
Synthesis of 1,2-bis {6- (4-cyanobiphenyl-4′-yloxy) hexyloxy} benzene target compound, measurement of physical properties, and measurement of voltage dependence of light transmittance are in accordance with the method of Example 1. I went. As reaction starting materials, 1,2-bis (6-bromohexyloxy) benzene and 4-cyano-4′-hydroxybiphenyl were used. These were reacted in the presence of potassium carbonate using cyclohexanone as a solvent to obtain the target compound. The phase transition temperature is determined by Iso. It became a nematic phase at Liq 124.0 ° C. and crystallized at 112 ° C. The mp was 128 ° C.
° C.

<Example 8>
1- {6- (4-Fluorobiphenyl-4'-yloxy) hexyloxy} -2- {3- (4-fluorophenyloxy) propyloxy} benzene Synthesis of the target compound Synthesized by Williamson synthesis through four steps of reaction did. One side of dibromopentane was alkylated using nucleophilic substitution reaction in the presence of potassium carbonate. Dibromopentane was used in excess to react only on one side. On the other hand, in order to synthesize the other side chain of the final compound, one side of dibromopropane was alkylated using a nucleophilic substitution reaction in the presence of potassium carbonate. Dibromopropane was used in excess to react only on one side. In the third stage reaction, an excess of catechol was used to alkylate the OH group on one side of catechol. In the fourth stage reaction, the remaining part was reacted in the same manner to synthesize the target compound. The structure of the compound was identified by ¹ H-NMR. A synthesis scheme is shown below (Chemical Formulas 24 and 25). In the scheme, (I) to (IV) indicate each reaction step.

  The synthesis method will be described in more detail. 1.88 g (10 mmol) of 4-fluoro-4′-hydroxybiphenyl and 3.66 g (15 mmol) of 1,6-dibromohexane are dissolved in cyclohexanone (25 ml), and 1.38 g (10 mmol) of potassium carbonate is added and heated. The mixture was stirred (70 ° C for 5 hours, 75 ° C for 1 hour). The solid was filtered off from the reaction mixture, and the filtrate was concentrated. The obtained solid was recrystallized using a mixed solvent of ethyl acetate / ethanol (2/1), and the yield of intermediate 4-fluoro-4 ′-(6-bromohexyloxy) biphenyl was 600 mg (1.7 mmol, yield). 17%) was obtained.

  4-fluoro-4′-hydroxyphenyl 800 mg (7.1 mmol) and 1,6-dibromopropane 2159 g (10.7 mmol) were dissolved in cyclohexanone (30 ml), and potassium carbonate 979.8 mg (7.1 mmol) was added. The mixture was stirred while heating (70 ° C. for 5 hours, 80 ° C. for 2 hours). The solid was filtered off from the reaction mixture, and the filtrate was concentrated. The obtained liquid was subjected to column chromatography using a mixed solvent of methylene chloride / hexane (2/1) as a developing solvent, and the yield of intermediate 4-fluoro-4 ′-(6-bromopropyloxy) phenyl was 548.4 mg (2 .35 mmol, yield 33.2%).

  Catechol 320 mg (3.0 mmol) and intermediate 4-fluoro-4 ′-(6-bromohexyloxy) biphenyl 507.4 mg (1.45 mmol) were dissolved in cyclohexanone (20 ml), and potassium carbonate 200 mg (1.45 mmol) And stirred while heating (70 ° C. for 4 hours, 80 ° C. for 2 hours, 85 ° C. for 3 hours). The solid was filtered off from the reaction mixture, and the filtrate was concentrated. The obtained solid was subjected to column chromatography using a mixed solvent of ethyl acetate / hexane (2/8) as a developing solvent, and yield of intermediate 1- {6- (4-fluorobiphenyl-4′-yloxy) hexyloxy} phenol was obtained. 148.3 mg (0.394 mmol, yield 27.2%) was obtained.

  112.7 mg (0.3 mmol) of the above intermediate and 70 mg (0.3 mmol) of the intermediate 4-fluoro-4 ′-(6-bromopropyloxy) phenyl were dissolved in cyclohexanone (20 ml) to obtain 47.9 mg of potassium carbonate. (0.35 mmol) was added and stirred while heating (120 ° C. for 5 hours, 130 ° C. for 1 hour). The solid was filtered off from the reaction mixture, and the filtrate was concentrated. The obtained solid was recrystallized using a mixed solvent of ethyl acetate / ethanol (2/1) to obtain the target compound yield 85.9 mg (0.16 mmol, yield 54.3%).

Physical property measurement It carried out similarly to Example 1 grade | etc.,. Upon cooling, it crystallized from an isotropic liquid (Iso.Liq) at 29.2 ° C. The mp during heating was 96.1 ° C.

Voltage dependency of light transmittance The same as Example 1 and the like. That is, 90 parts by weight of the host A described in Example 1 was mixed with 10 parts by weight of the compound of this example to prepare a liquid crystal composition. According to the method described in Example 1, the voltage dependence of transmittance was measured. As a result, the voltages when the transmittance changed by 10% and 50% were 7V and 10.5V, respectively. Therefore, it was shown that the compound of the present invention is a very useful compound in reducing the driving voltage.

  3 and 4 are graphs showing voltage dependence measurement results of light transmittance for Examples 1, 3, 4, 5, and 8. FIG. As shown in the figure, the liquid crystal composition obtained by adding the U-shaped compound of the present invention to the host material showed an excellent driving voltage reduction effect in any of the examples. In particular, the voltage reduction effect when the transmittance was changed by 10% was particularly great in the compound of Example 1. The voltage reduction effect when the transmittance was changed by 50% was particularly great in the compounds of Examples 8, 4, 3, and 5.

  As described above, since the U-shaped compound of the present invention is configured as described above, by adding a small amount thereof to a nematic liquid crystal composition or a chiral nematic liquid crystal composition, particularly a nematic liquid crystal material for display or a chiral nematic liquid crystal. The driving voltage in the material can be significantly reduced. And according to the liquid crystal composition containing the U-shaped compound of the present invention, a low power consumption liquid crystal display element can be constructed and manufactured. Therefore, it is an invention with extremely high industrial applicability.

It is a conceptual diagram which shows the basic molecular design of this invention U-shaped compound. The voltage dependence measurement result of the light transmittance in Example 1 and Comparative Example 1 is made into a graph. The voltage dependence measurement result of the light transmittance in each Example is made into a graph. It is the figure which expanded a part of graph of FIG.

Claims (5)

A U-shaped compound represented by the following general formula (Formula 1).

[In this formula, X ₀ is a connector that connects two mesogenic groups, and is a rigid group such as benzene or cyclohexane. A ₁ , A ₂ , C ₁ , and C ₂ are each independently a bonding group such as a single bond, an ether bond, an ester bond, or an amide bond. B ₁ and B ₂ are each an aliphatic compound spacer having an independent straight chain or branch. Y ₁ and Y ₂ are each independently a rigid group such as biphenyl, phenyl, benzoate, cyclohexane, benzene, phenylcyclohexane, terphenyl, phenylpyrimidine and the like. At least one of Z ₁ and Z ₂ is an independent electron withdrawing group or electron donating group. ] A U-shaped compound represented by the following general formula (Formula 2).

[In this formula, X is a rigid group such as benzene or cyclohexane. A ¹ , A ² , B ¹ , and B ² are each independently a bonding group such as a single bond, an ether bond, an ester bond, or an amide bond. m and n are each independently an integer of 1 or more. p and q are each independently an integer of 0 or 1. D and E are independent benzene ring substituents, and the substitution position and number are not limited. ] A compound represented by the following general formula (Formula 3).

[In this formula, m and n are each independently an integer of 3 to 15, p and q are each independently an integer of 0 or 1, X and Y are each independently H, F, CF ₃ , It is a substituent on the benzene ring such as OCF ₃ , CF ₂ H, CFH ₂ , OCF ₂ H, OCFH ₂ , and the substitution position and number are not limited. ] A liquid crystal composition comprising the compound according to claim 3. A nematic liquid crystal composition or a chiral nematic liquid crystal composition, wherein the nematic liquid crystal composition or the chiral nematic liquid crystal composition contains the compound according to claim 3.

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