JP2001348351A - Liquid crystal compound and charge transfering liquid crystal composition utilizing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid crystalline charge transfering compound having a high fluidity, a low transition temperature to a liquid crystal phase and a wide liquid crystal temperature range and further high charge mobility. SOLUTION: This liquid crystal compound is represented by the general formula (I) (wherein, X1, X2, Y1 and Y2 denote each independently oxygen atom or sulfur atom; R1 and R2 denote each independently an aliphatic hydrocarbon group; l and n denote each independently 0 or 1; and m and o denote each independently an integer of 1-20). The charge transporting liquid crystal composition comprises the liquid crystal compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an application to a one-dimensional conductor, and more particularly, to a charge transport material for an electrophotographic photosensitive member.
The present invention relates to a novel liquid crystal compound having a charge transporting property, which is useful as a material for an L element, an optical sensor, a photolithography, a solar cell, nonlinear optics, and the like.

[0002]

2. Description of the Related Art Conventionally, stilbene compounds, arylamine compounds, hydrazone compounds, butadiene compounds and the like have been known as organic charge transporting materials. These are generally used by being dispersed in a resin such as polycarbonate, and their charge mobility is as small as 10 ^-6 to 10 ^-4 cm ² / V · s, so their use is limited, and they are used for electrophotographic photoreceptors and the like. It's just that.

As the liquid crystal charge transport compound, compounds having various structures are known, and as a representative compound which has been reported to have high charge mobility, for example, in discotic liquid crystals, Phys. Rev. Lett. 2,70,457 (1993), 2,3,6,7,10,11-hexapentyloxytriphenylene, and Nature, 371,141 (1994)
7,10,11-hexahexylthiotriphenylene has been described. Phys. Rev. Let for smectic liquid crystals
t., 78, 2184 (1997), 2- (4'-heptyloxyphenyl) -6-dodecylthiobenzothiazole was added to Appl.
s. Lett., 71, 602 (1997) describes 2- (4'-octylphenyl) -6-dodecyloxynaphthalene as Appl. Phys.
tt., 73, 3733 (1998), 2- (4'-octylphenyl)
-6-Butoxynaphthalene has been added to 2,5-Dialkyl-2,2 '
5 ', 2 "-terthiophene is described.

Liquid crystal charge transport compounds exhibit high charge mobility in the liquid crystal state. However, the above compounds have problems such as a high transition point to a liquid crystal phase and a narrow liquid crystal temperature range. Therefore, there is a problem that the above-mentioned problem must be solved by mixing with a large amount of other compounds at the expense of charge mobility in order to reduce the charge mobility.

On the other hand, as a method for lowering the transition temperature to the liquid crystal phase, JP-A-7-309813 discloses 2, 3, 6, 7, 1
It is described that an ether group is introduced into the alkyl group of 0,11-hexa (4-alkyloxybenzoyloxy) triphenylene. However, the transition temperature to liquid crystal is still very high, close to 100 ° C. Furthermore,
It is not described whether this compound is a liquid crystal charge transport compound.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal charge transporting compound which solves the above-mentioned problems, and specifically, has a low transition temperature to a liquid crystal phase having a high fluidity, An object of the present invention is to provide a liquid crystal charge transport compound having a wide temperature range and higher charge mobility.

[0007]

As a result of intensive studies, the present inventors have found that the object of the present invention can be achieved as follows. That is, the present invention provides: (1) a liquid crystal compound represented by the general formula (I).

[0008]

Embedded image

Wherein X ₁ , X ₂ , Y ₁ and Y ₂ each independently represent an oxygen atom or a sulfur atom, and R ₁ and R ₂ each independently represent an aliphatic hydrocarbon group. n independently represents 0 or 1; m and o each independently represent 1 to 2;
Represents an integer of 0. (2) The liquid crystal compound according to (I), wherein in formula (1), X ₁ , X ₂ , Y ₁ and Y ₂ are each an oxygen atom. (3) The liquid crystal compound according to (1) or (2), wherein n is 0 in the general formula (I). (4) The liquid crystal compound according to any one of (1) to (3), wherein 1 is 0 in the general formula (I). (5) In the formula (I), R ₁ and R ₂ are each an ethyl group, m is an integer of 3 to 6, and o is an integer of 2 to 6, Liquid crystal compound. (6) A charge transporting liquid crystal composition containing the liquid crystal compound according to any one of (1) to (5) as a charge transporting material. I will provide a.

Hereinafter, the compound represented by formula (I) of the present invention will be described in detail. In the general formula (I), X
₁ , X ₂ , Y ₁ , and Y ₂ each independently represent an oxygen atom or a sulfur atom, but is preferably an oxygen atom for ease of synthesis. R ₁ and R ₂ each independently represent an aliphatic hydrocarbon group, preferably an unsubstituted linear alkyl group, more preferably a methyl group, an ethyl group, or a propyl group having 3 or less carbon atoms. Among them, an ethyl group is particularly preferred from the viewpoints of transition temperature to liquid crystal, charge transportability, and the like. l and n each independently represent 0 or 1, and m and o each independently represent 1-2.
Represents an integer of 0. Among them, preferably, l and n are 0, m
Represents an integer of 3 to 6, and o represents an integer of 2 to 6.

Hereinafter, specific examples of the compound represented by formula (I) of the present invention will be shown, but the present invention is not limited thereto.

[0012]

Embedded image

The synthesis examples of the compound represented by the general formula (I) of the present invention are shown below, but the present invention is not limited thereto.

[0014]

Embedded image

(Where R ₁ , R ₂ , X ₁ , X ₂ , Y ₁ , Y ₂
And l, m, n, and o have the same meaning as in formula (I). R ′ represents a lower alkyl group, and Z ₁ and Z ₂ represent a halogen atom. )

A) In the case of n = 0 After reacting 2-bromo-6-methoxynaphthalene or 2-bromo-6-thiomethoxynaphthalene with magnesium in dry THF, trimethoxyborane or triisopropoxyborane By reacting alkoxyborane and hydrolyzing with hydrochloric acid, 6-methoxynaphthalene-2-boric acid or 6-thiomethoxynaphthalene-
2-boric acid is obtained. Then, this Pd (PPh _{3) 4} are reacted with p- alkyl halogenated benzene such as p- alkyl bromobenzene or p- alkyl chlorobenzene as catalyst 2- (4'-alkylphenyl) -
6-methoxynaphthalene or 2- (4'-alkylphenyl) -6-thiomethoxynaphthalene is obtained.

Next, 2- (4'-alkylphenyl) -6-methoxynaphthalene obtained above or 2-
(4'-Alkylphenyl) -6-thiomethoxynaphthalene is reacted with boron tribromide in anhydrous dichloromethane to give 2- (4'-alkylphenyl) -6-hydroxynaphthalene or 2- (4'-alkylphenyl )
-6-thiohydroxynaphthalene is obtained, and an alkoxyalkylene bromide, an alkoxyalkylene halide such as an alkoxyalkylene chloride, or a thioalkoxyalkylene bromide or a thioalkoxyalkylene halide such as a thioalkoxyalkylene chloride is converted to an alkali metal such as potassium carbonate. By reacting in the presence of 2- (4'-alkylphenyl) -6
(Alkoxyalkyleneoxy) naphthalene, or 2
-(4'-alkylphenyl) -6- (thioalkoxyalkyleneoxy) naphthalene or 2- (4'-alkylphenyl) -6- (alkoxyalkylenethioxy) naphthalene, or 2- (4'-alkylphenyl)- 6- (thioalkoxyalkylenethioxy) naphthalene can be obtained.

B) When n = 1. The p- methoxy halogenated benzene or p- thiomethoxide halogenated benzene in place of p- alkyl benzene halide in a) Pd (in the presence of PPh _{3) 4} 6-methoxy-2-boric acid, or 6- Reaction with thiomethoxynaphthalene-2-boric acid, followed by a)
By carrying out the reaction in the same manner as described above, the compound of the general formula (I) can be obtained.

The liquid crystal compounds used in the present invention may be used alone or as a mixture of two or more. When a plurality of the liquid crystal compound of the present invention and another compound are used as a mixture, the compound only needs to exhibit liquid crystallinity in a mixed state, and not all compounds need to exhibit liquid crystallinity.
The composition exhibiting liquid crystallinity may be adjusted by mixing with a compound having liquid crystallinity and a compound having a core but not exhibiting liquid crystallinity.

The charge transporting liquid crystal composition containing the liquid crystal compound of the present invention can be used without any particular limitation as long as it is generally recognized as a liquid crystal phase in this field. Among them, a smectic phase is exhibited. Are preferred.

In the charge transporting liquid crystal composition used in the present invention, a liquid crystal compound having no charge transporting property can be added in a range not exceeding 50% by weight in the total composition. Such liquid crystal compounds include nematic liquid crystal compounds,
Smectic liquid crystal compounds, cholesteric liquid crystal compounds, and the like can be used without any particular limitation as long as they are generally recognized as liquid crystals in this technical field, but as the amount of addition increases, the charge transport performance tends to decrease. It is necessary to adjust the amount appropriately. Next, a method for producing a charge transport material using the liquid crystal compound or liquid crystal composition of the present invention will be described.

The liquid crystal compound or the liquid crystal composition of the present invention is applied to a substrate, or a cell is prepared using two or more substrates and sealed in the cell, or a dispenser is placed on the substrate. After dropping by, for example, another substrate may be used in a stacked state.

The application to the substrate is a method of applying the liquid crystal compound or the liquid crystal composition of the present invention as it is, or a method of applying a coating solution obtained by dissolving the liquid crystal compound or the liquid crystal composition in a solvent, followed by drying. May be.

As the solvent used in the latter method, known and commonly used solvents can be used. Examples of such a solvent include ketones such as acetone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 2-heptanone, methyl isobutyl ketone, and butyrolactone, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, and pen. Alcohols such as tanol and octanol, tetrahydrofuran, dioxane, ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and ethylene glycol dimethyl ether, ethyl acetate, butyl acetate, ethyl propionate, methyl cellosolve acetate, and ethyl cellosorb acetate Esters, such as toluene, xylene, aromatic compounds such as chlorobenzene, dimethylacetamide, dimethyl Such amides formamide, methylene chloride, chloroform, dichloroethane, etc. halogenated hydrocarbons such as trichloroethane and the like. These solvents may be used alone or in combination of two or more. The mixing ratio of the solvent can be appropriately adjusted as necessary, such as the required film thickness and application conditions when applying the liquid crystal compound or the liquid crystal composition to the substrate.

The coating method includes, for example, wire bar coating, spin coating, roll coating, dip coating, spray coating, die coating, or dipping and pulling.
Known and commonly used coating methods can be widely used. Among these coating methods, spin coating and die coating are preferred.

The substrate on which the liquid crystal compound or the liquid crystal composition of the present invention is applied, or the substrate constituting the cell in which the liquid crystal compound or the liquid crystal composition is sealed can be used regardless of an organic material or an inorganic material.

As the organic material constituting the substrate, for example, polyethylene terephthalate, polycarbonate,
Polyimide, polymethyl methacrylate, polystyrene,
Examples include polyethylene, polyvinyl chloride, polytetrafluoroethylene, polychlorotrifluoroethylene, polyarylate, polysulfone, cellulose and the like. Examples of the inorganic material forming the substrate include silicon, glass, and metal.

The surfaces of these substrates can be treated, for example, as electrodes. As a material constituting the electrode, for example, indium tin oxide (I
TO), indium oxide, zinc oxide, tin oxide, sodium, potassium, magnesium, aluminum, gold, silver,
Copper, indium and the like can be mentioned.

The surface of the substrate may be subjected to an alignment treatment in order to align the liquid crystal compound in a certain direction. As the alignment process, for example, a method of rubbing treatment, and a method of oblique evaporation of Si0 ₂ to the substrate surface and the like of the substrate surface with a cloth or the like. In the case of using a substrate that has not been subjected to an alignment treatment, the liquid crystal compound can be aligned using an electric field or a magnetic field. These alignment means may be used alone or in combination.

When a suitable orientation cannot be obtained by rubbing the substrate with a cloth or the like, an organic thin film such as a polyimide thin film or a polyvinyl alcohol thin film is formed on the surface of the substrate according to a known method, and this is rubbed with a cloth or the like. May be. Normal twisted nematic (TN)
Alternatively, a polyimide thin film providing a pretilt angle as used in a super twisted nematic (STN) cell may be used. Further, a photo-alignment method can be used instead of the rubbing treatment.

When the orientation state is controlled by an electric field, a substrate having an electrode layer can be used. In this case, it is preferable to form an organic thin film such as the above-mentioned polyimide thin film on the electrode.

The charge transporting liquid crystal composition of the present invention can produce electronic devices such as EL devices, optical sensors, electrophotographic photosensitive members, and image recording devices. When used for an EL device, the charge transporting liquid crystal composition of the present invention, to which a light emitting material is added as necessary, is formed as a light emitting layer by sandwiching it between two electrodes (at least one of which is a transparent electrode such as ITO). be able to. In the case of a multilayer organic light-emitting device, the charge transport material of the present invention can be used as a hole transport layer, an electron transport layer, or a light-emitting layer. When used for an optical sensor, a change in current due to light irradiation can be detected by sandwiching the charge transport material of the present invention between two electrodes (at least one of which is transparent). When used as an electrophotographic photoreceptor or an image recording element, it can be prepared by laminating a charge generation layer and the charge transport layer of the present invention on a substrate or an electrode.

The charge generation layer constituting the electrophotographic photosensitive member or the image recording element is a vapor deposition layer of a charge generation material or a layer in which the charge generation material is dispersed in a binder resin.

Examples of the charge generating material include disazo pigments such as chlorodian blue, polycyclic quinone pigments such as anthrone, indigo pigments such as perylene pigment, indigo and thioindigo, and phthalocyanine pigments.

Examples of the binder resin include polycarbonate resin, polyvinyl butyral, polystyrene, polyvinyl acetate, and acrylic resin.

The resin-dispersed type charge generation layer comprises the charge generation substance together with a binder resin and a solvent in an amount of 0.3 to 4 times.
A dispersion liquid well dispersed by a method such as a homogenizer, an ultrasonic dispersion, a ball mill, a vibrating ball mill, a sand mill, an attritor, a roll mill, and a liquid collision type high-speed disperser can be formed by coating and drying. The thickness of the charge generation layer is preferably 5 μm or less, particularly preferably 0.1 to
2 μm is good.

[0037]

EXAMPLES The method for synthesizing the liquid crystal compound of the present invention will be specifically described below, and the results of measurement of the liquid crystal transition temperature and the charge mobility will be described. In the examples, ¹ H NMR was measured using CDCl ₃ as a solvent and TMS as a reference substance, showing the chemical shift δ (ppm) of the obtained main spectrum. The attribution was shown.

The transition temperature of the compound of the general formula (I) to each phase was measured using a DSC and a polarizing microscope. At the phase transition temperature, K represents a crystalline phase, Sm represents a smectic phase, Sm1 represents a smectic phase 1, Sm2 represents a smectic phase 2, and I represents an isotropic liquid.

The charge mobility was measured and measured by the TOF method shown below. That is, the obtained compound was heated to an isotropic liquid phase, and a glass cell having two aluminum electrodes heated to the same temperature (interelectrode distance 50 μm, electrode area 1.0 c
m ² ) was injected in the state of an isotropic liquid phase to obtain a sample.
After adjusting the temperature of the sample so that the injected compound becomes a smectic phase, 30 V is maintained between the electrodes while maintaining the temperature.
Was applied so that the excitation light incident side became a positive electrode, and the excitation light was irradiated. The excitation light is nitrogen laser (wavelength = 337n)
m, pulse width = 600 ps). Photocurrent generated by irradiation is measured with a digital oscilloscope,
Analysis was performed to determine hole mobility.

[0040]

Example 1 2- (4'-octylphenyl) -6
Synthesis of (ethoxyethoxy) naphthalene (E-72).

A) Synthesis of 6-methoxynaphthalene-2-boric acid. 23.7 g (0.1 mol) of 2-bromo-6-methoxynaphthalene in 6 g (0.11 mol) of metallic magnesium
Was dissolved in 85 ml of anhydrous THF, and 5 ml of the solution was dropped and heated. After reflux, the heat source was removed, and the remaining THF solution was added dropwise at such a rate that reflux did not stop. After the addition, the mixture was further heated and refluxed for 1 hour. Triisopropyl borate 20.8g
(0.11 mol) was dissolved in 32 ml of THF.
After cooling to below ° C, the THF solution was added dropwise. After dropping -4
After stirring at 0 to -50 ° C for 30 minutes, the mixture was further stirred at room temperature for 2 hours. Then, 100 ml of 10% hydrochloric acid was added dropwise at -10 to -20 ° C, and the mixture was stirred at the same temperature for 30 minutes, further stirred at room temperature for 2 hours, extracted with ethyl acetate / saturated saline, and the oil layer was extracted with sodium hydrogen carbonate solution. Washed. After the oil layer was dried over magnesium sulfate, the solvent was distilled off, and the crude product was washed with stirring in toluene and washed with 6-methoxynaphthalene-2-boric acid.
3 g (yield: 37.5%) were obtained.

B) 2- (4'-octylphenyl) -6
-Synthesis of methoxynaphthalene. 11 g of 6-methoxynaphthalene-2-boric acid (0.03
3 mol), 9 g of p-octylbromobenzene (0.0 g)
33 mol) and 0.96 g of Pd (PPh ₃ ) ₄ (0.
[00083 mol) was dispersed in 130 ml of dimethoxyethane, and 120 ml of a 14% aqueous solution of potassium carbonate was added thereto to prepare 1
Refluxed for hours. After cooling, the resulting precipitate was separated by filtration, washed with water and methanol, and washed with 2- (4'-octylphenyl) -6.
10.5 g (yield: 92%) of -methoxynaphthalene was obtained.

C) 2- (4'-octylphenyl) -6
-Synthesis of hydroxynaphthalene. 9.1 g (0.026 mol) of 2- (4'-octylphenyl) -6-methoxynaphthalene is dissolved in 155 ml of anhydrous dichloromethane, and 12.8 ml of boron tribromide is dissolved in 80 ml of anhydrous dichloromethane in a nitrogen stream at -50 ° C or lower. After the dissolved solution was added dropwise, the mixture was stirred at room temperature for 8 hours. Then 80
The mixture was stirred in 0 ml of water, and the resulting precipitate was filtered off and recrystallized from ethanol to give 2- (4'-octylphenyl) -6.
-Hydroxynaphthalene 7.2 g (Yield: 82.8%)
I got

D) 2- (4'-octylphenyl) -6
-Synthesis of (ethoxyethoxy) naphthalene (E-72). 5 g (0.015 mol) of 2- (4′-octylphenyl) -6-hydroxynaphthalene, 3.8 g (0.025 mol) of 2-bromoethylethyl ether and 7.8 g of potassium carbonate are dispersed in 30 ml of cyclohexanone and refluxed for 4 hours. did. The mixture was poured into water and stirred. The resulting precipitate was separated by filtration, recrystallized from ethanol, and further recrystallized from acetonitrile to give 2.7 g of 2- (4'-octylphenyl) -6- (ethoxyethoxy) naphthalene (yield). : 44.5%).

The NMR spectrum of the above compound was as follows. ¹ H NMR measurement results δ = 7.94 (1H, s, aromatic), 7.78 (2
H, d, aromatic), 7.68 (1H, dd, aromati)
c), 7.61 (2H, d, aromatic), 7.28 (2
H, d, aromatic), 7.21 (1H, dd, aromati)
c), 7.16 (1H, d, aromatic), 4.26 (2
_{H, t, -OCH 2 CH 2} O -), 3.87 (2H, t,
_{-OCH 2 CH 2 O -),} 3.65 (2H, quin, -
_{OCH 2 -), 2.66 (2H} , t, Ph-CH 2 -),
1.65 (2H, quin, Ph- CH 2 -CH 2),
_{1.25~1.34 (13H, m, -CH 2} -, - C
_{H 3), 0.89 (3H,} t, -CH 3)

When the phase transition temperature of the obtained compound was measured by using DSC, the following phase transition temperature was shown.

Next, the charge mobilities of Sm1 and Sm2 are measured by TOF.
2 × 10 ^-2 cm ² / V ·
s, 2 × 10 ⁻³ cm ² / V · s.

Thus, it can be seen that this compound shows a liquid crystal at room temperature of 32.0 ° C., and maintains Sm1 showing high charge mobility in a wide temperature range up to 84.1 ° C.

[0049]

Example 2 Synthesis of 2- (4'-decylphenyl) -6- (ethoxyethoxy) naphthalene (E-73).

Synthesis was carried out in the same manner as in Example 1 except that p-decylbromobenzene was used instead of p-octylbromobenzene, and 2- (4′-decylphenyl) -6- (ethoxyethoxy) was used. Naphthalene was obtained.

¹ H NMR measurement results δ = 7.51 (1H, d, aromatic), 7.49 (2
H, t, aromatic), 7.45 (1H, s, aromati)
c), 7.26 (2H, d, aromatic), 7.22 (2
H, d, aromatic), 7.00 (1H, d, aromati)
c), 6.98 (1H, d, aromatic), 4.16 (2
_{H, t, -OCH 2 CH 2} O -), 3.81 (2H, t,
_{-OCH 2 CH 2 O -),} 3.62 (2H, quin, -
OCH _2- ), 2.62 (2H, t, Ph-CH _2- ),
1.62 (2H, quint, Ph- CH 2 -CH 2),
_{1.25~1.32 (17H, m, -CH 2} -, - C
_{H 3), 0.88 (3H,} t, -CH 3)

When the phase transition temperature of the obtained compound was measured by using DSC, the following phase transition temperature was shown.

Next, when the charge mobility of Sm was measured by the TOF method, it showed a high charge mobility of 1.3 × 10 ⁻² cm ² / V · s.

[0054]

Example 3 2- (4'-ethoxyethoxyphenyl)
Synthesis of 6- (ethoxyethoxy) naphthalene (E-2).

A) Synthesis of 4-methoxyphenylboric acid. 18.7 g (0.1 mol) of 4-bromoanisole was added to 6 g (0.11 mol) of metallic magnesium in anhydrous THF5.
5 ml of a solution dissolved in 0 ml was dropped and heated. After reflux, the heat source was removed, and the remaining THF solution was added dropwise at such a rate that reflux did not stop. After the addition, the mixture was further heated and refluxed for 1 hour. Triisopropyl borate 20.8g (0.11mo
l) was dissolved in 30 ml of THF, and the above THF solution was added dropwise after cooling to −50 ° C. or lower. After the dropwise addition, the mixture was stirred at −40 to −50 ° C. for 30 minutes, and further stirred at room temperature for 2 hours. Then -1
100 ml of 10% hydrochloric acid was added dropwise at 0 to -20 ° C, and the mixture was stirred at the same temperature for 30 minutes, further stirred at room temperature for 2 hours, extracted with ethyl acetate / saturated saline, and the oil layer was washed with sodium hydrogen carbonate solution. . After drying the oil layer with magnesium sulfate, the solvent was distilled off, and the crude product was washed by stirring in hexane.
6.4 g of methoxyphenylboric acid (yield: 42.0%)
I got

B) 2- (4'-methoxyphenyl) -6
-Synthesis of methoxynaphthalene. 3.0 g of 4-methoxyphenylboric acid (0.02 mol
l), 4.14 g of 2-bromo-6-methoxynaphthalene
(0.017 mol) and 0.5 g of Pd (PPh ₃ ) ₄
(0.00043 mol) in 50 ml of dimethoxyethane
And 50 ml of a 14% aqueous solution of potassium carbonate was added thereto, followed by refluxing for 1 hour. After cooling, the resulting precipitate was separated by filtration, washed with water and methanol, and recrystallized from ethyl acetate to give 2- (4 ′
-Methoxyphenyl) -6-methoxynaphthalene 3.6
g (yield; 68.1%).

C) 2- (4'-hydroxyphenyl)-
Synthesis of 6-hydroxynaphthalene. Dissolve 3.2 g (0.012 mol) of 2- (4′-methoxyphenyl) -6-methoxynaphthalene in 60 ml of anhydrous dichloromethane, and dissolve 12 ml (0.12 mol) of boron tribromide in a nitrogen stream at −50 ° C. or lower. After dropwise adding a solution dissolved in 70 ml of dichloromethane, the mixture was stirred at room temperature for 8 hours. Next, the mixture was poured into 400 ml of water and stirred. The resulting precipitate was separated by filtration and recrystallized with ethanol / water (1/1) to give 2-
2.5 g (yield: 88.3%) of (4'-hydroxyphenyl) -6-hydroxynaphthalene was obtained.

D) 2- (4'-ethoxyethoxyphenyl) -6- (ethoxyethoxy) naphthalene (E-2)
Synthesis of 2.36 g (0.01 mol) of 2- (4′-hydroxyphenyl) -6-hydroxynaphthalene, 4.59 g (0.03 mol) of 2-bromoethyl ethyl ether, and 10.4 g of potassium carbonate were dispersed in 15 ml of cyclohexanone, and Refluxed for hours. After stirring in water, the resulting precipitate was separated by filtration, recrystallized from ethanol / isopropanol (1/2), and further recrystallized from acetonitrile to give 2- (4'-
1.75 g (yield: 46.0%) of ethoxyethoxyphenyl) -6- (ethoxyethoxy) naphthalene was obtained.

The NMR spectrum of the above compound was as follows. ¹ H NMR measurement results δ = 7.89 (1H, d, aromatic), 7.82 (2
H, d, aromatic), 7.70 (1H, d, aromati)
c), 7.62 (2H, dquartet, aromatic), 7.1
7 (2H, dt, aromatic), 7.01 (2H, dd, aromatic)
aromatic), 4.20 (4H, td , -OCH 2 CH 2 O
−), 3.83 (4H, td, —OCH ₂ CH ₂ O—),
3.62 (4H, quart d, -OCH 2 -), 1.
_{26 (6H, dt, -CH 3} )

When the phase transition temperature of the obtained compound was measured by using DSC, the following phase transition temperature was shown.

Next, when the charge mobility of Sm was measured by the TOF method, the charge mobility was as high as 1.5 × 10 ⁻² cm ² / V · s.

[0062]

Comparative Example 1 2- (4′-octylphenyl) -6-butoxynaphthalene was synthesized according to the method described in JP-A-10-231260. The phase transition temperature of this compound,
When the charge mobility was measured, the following values were obtained.

Next, the charge mobility at Sm1 and Sm2 is represented by T
When measured by the OF method, each was 9 × 10 ⁻³ cm ⁻³ /
vs. 1.4 × 10 ⁻³ cm ² / vs.

[0064]

Comparative Example 2 The following compound was synthesized using 1-bromo-2- (2-methoxyethoxy) ethane in place of 2-bromoethylethyl ether in Example 1.

[0065]

Embedded image

The phase transition temperature of this compound was measured and was as follows.

Next, when the charge mobility of this product was measured by the TOF method, a non-dispersion type waveform was not obtained, and no charge mobility was obtained.

[0068]

Comparative Example 3 The following compound was synthesized using β-bromophenetol instead of 2-bromoethyl ethyl ether in Example 1.

[0069]

Embedded image

When the phase transition temperature of this compound was measured, it showed no liquid crystal phase.

[0071]

The charge transporting material of the present invention has a high charge transporting ability. In particular, in general formula (I), l. The compound shown in Example 1 in which n is 0, m is 6, o is 2, R ₁ and R ₂ are ethyl groups, and Y ₁ and Y ₂ are oxygen shows a smectic phase at around room temperature and high charge transport. Application to one-dimensional conductors, more specifically, charge transport materials for electrophotographic photoreceptors, EL elements, optical sensors, photolithography,
It is very useful as a material for solar cells and nonlinear optics.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 5/06 311 G03G 5/06 311 // C09K 19/32 C09K 19/32 F term (reference) 2H068 AA20 BA12 FA12 4H006 AA01 AA03 AB64 GP01 GP03 TA04 TB39 TB41 4H027 BA03 BD02 DK02 DK03

Claims (6)

[Claims] 1. A liquid crystal compound represented by the following general formula (I). Embedded image (Wherein X ₁ , X ₂ , Y ₁ and Y ₂ each independently represent an oxygen atom,
Represents a sulfur atom, and R ₁ and R ₂ each independently represent an aliphatic hydrocarbon group. Also, l and n each independently represent 0 or 1, and m and o each independently represent an integer of 1 to 20. ) 2. In the general formula (1), X ₁ , X ₂ , Y ₁ , Y ₂
The liquid crystal compound according to claim 1, wherein each is an oxygen atom. 3. The liquid crystal compound according to claim 1, wherein n is 0 in the general formula (1). 4. The liquid crystal compound according to claim 1, wherein 1 is 0 in the general formula (1). 5. The method according to claim ₁ , wherein R ₁ and R ₂ are ethyl groups, m is an integer of 3 to 6, and o is an integer of 2 to 6 in the general formula (1). Liquid crystal compound. 6. A charge transporting liquid crystal composition comprising the liquid crystal compound according to claim 1 as a charge transporting material.