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Description
LIQUID CRYSTAL COMPOSITION COMPRISING NOVEL
SILICON CONTAINING COMPOUNDS AND LIQUID CRYSTAL
DISPLAY DEVICE USING THE SAME
Technical Field
[1] The present invention relates to a novel silicon-containing compound and a liquid
crystal composition comprising the same. More particularly, the present invention
relates to a novel nematic liquid crystal compound, which has low viscosity and high
positive dielectric anisotropy, a liquid crystal composition comprising the same
compound, and a liquid crystal display device using the same composition.
Background Art
[2] In general, liquid crystal compounds having optical anisotropy (An) and dielectric
anisotropy (Ae) are widely used in display devices such as clocks, notebook PCs,
mobile phones, televisions and monitors. Such liquid crystal compounds are in-
creasingly in demand. Liquid crystal compounds used in such display devices include a
nematic liquid crystal phase, a smectic liquid crystal phase and a cholesteric liquid
crystal phase. Among those phases, nematic phases are the most widely used. In
practice, various liquid crystal compounds are used in the form of a composition.
Liquid crystal compositions should be stable against water, light, heat, air, electric
fields or the like, and have to ensure the chemical stability among the compounds
forming the composition under the conditions of particular use. In order to use a liquid
crystal compound in a display device, the liquid crystal compound should be in
harmony of physical properties, including a wide range of LIquid crystalphase tem-
peratures, optical anisotropy value (An) and dielectric anisotropy value (AE), viscosity
and conductivity. Properties of a liquid crystal compound required for a display device
depend on the specific type of the display device. Therefore, there is an imminent need
for a novel liquid crystal device that satisfies the above properties at the same time.
Recently, there has been a need for a liquid crystal display device having a fast
response time in order to treat a great amount of information promptly.
Disclosure of Invention
Technical Problem
[3] Therefore, the present invention has been made in view of the above-mentioned
problems. It is an object of the present invention to provide a novel liquid crystal
compound, which has low viscosity as well as high positive dielectric anisotropy so as
to permit optimization of display. It is another object of the present invention to

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provide a liquid crystal composition comprising the above compound. It is still another
object of the present invention to provide a liquid crystal display device manufactured
by using the above composition.
Technical Solution
[4] The present invention provides a novel silicon-containing compound represented by
the following formula 1, a liquid crystal composition comprising the above compound,
and a liquid crystal display device comprising a liquid crystal layer prepared from the
above liquid crystal composition:
[5] [Formula 1]
[6]



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9
[11] wherein the substituents, which are introduced into ring B, ring C or ring D and
represented by L to L , are independent from each other, even if they have the same
designations;
[12] M is selected from C, N and Si, with the proviso that if M is N, L or L is null;
[13] Z is C;
[14] each of a, a and a is independently selected from C, NR and O;
[15] E is selected from the group consisting of SiMe2Ok2 (CO) ,SiEt2Ok2 (CO) ,SiF2O
k2(CQ2)n2 , SiCl2Ok2 (CQ2)n2 , SiMe2 (CQ)n2 Ok2 , SiEt2(CQ2)n2Ok2, siF2(CQ2)n2 Ok2 , SiCl2(CQ
2)n2Ok2, Ok2SiMe2(CQ2)n2 ,Ok2 SiEt2(CQ2)n2,Ok2 SiF2(CQ2)n2,Ok2 SiCl2(CQ2)n2, (CQ2)n2O
SiMe2, (CQ2)n2Ok2SiEt2, (CQ2)n2Ok2SiF2,(CQ2)n2Ok2SiCl2, Ok2(CQ2)n2SiMe2,Ok2(CQ2)
SiEt2,Ok2(CQ2)n2SiF2,Ok2(CQ2)n2SiCl2,(CQ2)n2SiMe2Ok2,(CQ2)n2SiEt2Ok2,(CQ2)n2SiF2
Ok2, (CQ2)n2SiCl2Ok2, (CH2)n2, C≡C, O, S, COO, OCO, CF2O, OCF2, OCOO, CH2O,
CH2CO, OCH2 and COCH2, wherein k2 is 0 or 1, Q is H or F, and n is an integer
between 0 and 3;
[16] R is selected from the group consisting of H, a C1~C15 alkyl group, a C2 ~C15 alkene
group and an alkoxy group (R1O), wherein the alkene group is CH=CH2, CH=CHCH3
(E,Z), CH2CH=CH2, CH=CHCH2CH3(E,Z), CH2CH=CHCH3 (E,Z), CH2CH2CH=CH2,
CH=CHCH2CH2CH3(E,Z), CH2CH=CHCH2CH3(E,Z), CH2CH2CH=CHCH3(E,Z) or
CH2CH2CH2CH=CH2;
[17] R is selected from the group consisting of H, a C1 ~C15 alkyl group and a C2 ~C15
alkene group, wherein the alkene group is CH=CH2, CH=CHCH3 (E,Z), CH2CH=CH2,
CH=CHCH2CH3 (E,Z), CH2CH=CHCH3 (E,Z), CH2CH2CH=CH2, CH=CHCH2CH2CH
(E,Z), CH2CH=CHCH2CH (E,Z), CH2CH2CH=CHCH3 (E,Z) or CH2CH2CH2CH=CH
2;'
[18] X is selected from the group consisting of H, SiR2R3R4 , CF3, OCF3, CN, NCS,
halogen atoms and R;
[19] each of R2, R3 and R4 is independently selected from R and halogen atoms;
[20] each of 1,L2,L3,L4,L5,L6 and L7 is independently selected from the group
consisting of H, halogen atoms, CN, CF3, OCF3 and NCS;
[21] each of o, p and q independently represents an integer between 0 and 2; and
[22] at least one of E, A and X contains silicon.
[23] Hereinafter, the present invention will be explained in more detail.
[24] The present invention provides a novel silicon-containing compound that may be

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applied in various display devices, a liquid crystal composition essentially comprising
the silicon-containing compound, preferably a positive nematic liquid crystal
composition, and a liquid crystal display device using the above liquid crystal
composition. The silicon-containing compound is characterized by having low
viscosity, and zero (0) or high positive (+) dielectric anisotropy.
[25] High dielectric anisotropy is required for the operation of a liquid crystal under a
low driving voltage. According to the present invention, the liquid crystal compound
has symmetry of substituents based on the major axis of the molecule, thereby
providing high positive dielectric anisotropy.
[26] Low viscosity is required to obtain a fast response time of a liquid crystal.
According to the compound of the present invention, it is possible to obtain low
viscosity by introducing a silicon-containing substituent into at least one of the linking
groups (A and E) and terminal group (X), or both of the linking groups and terminal
group.
[27] Further, according to the present invention, it is possible to improve dipole moment
by introducing a halogen atom and/or alkyl group as a substituent for the hydrogen
atom, which forms a primary bond with silicon when a silicon-containing substituent is
introduced into at least one of the linking groups and/or terminal group. Such improved
dipole moment results in improvement in the dielectric anisotropy, which is affected
significantly by the polarizability and dipole moment.
[28] Preferred embodiments of the silicon-containing compound represented by formula
1 according to the present invention, which comprise preferred examples of ring B and
ring C, are represented by the following formulae 2~10. However, the scope of the
present invention is not limited thereto.
[29] [Formula 2]
[30]

[31] [Formula 3]
[32]

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[47] wherein Z is C;
[48] M is C, Nor Si, with the proviso that if M is N,L3 or L7 is null;
[49] each of a , a and a is independently selected from C, NR and O;
[50] each of L1, L2, L3, L4, L5, L6 and L7 is independently selected from the group
consisting of H, halogen atoms, CN, CF3, OCF3 and NCS; and
[51] A, E, R, X, o, p and q are the same as defined in formula 1.
[52] Particular preferred examples of the compounds represented by formulae 2~10
include the following compounds. However, the scope of the present invention is not

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[59] wherein A is selected from the group consisting of SiOkl(CQ2)nl, Si(CQ2)nlOkl, (CQ2
)nlOklSi,(CQ2)nlSiOkl,Okl(CQ2)nlSi and Ok1Si(CQ2)n1, and k1, Q,n1,R,R2,R3,R4,L1,L
2, L3 , L4 , L5 , L7 , X, M, a1, a2 and a3 are the same as defined in formula 1.
[60] Stereoisomers of the silicon-containing compound represented by formula 1 are
also included in the scope of the present invention. Herein, the silicon-containing
compound having stereoisomers is present preferably in the trans-form with liquid
crystal characteristics. Additionally, stereoisomers of the silicon-containing compound
may be present in the ratio of trans-isomencis-isomer of 85~100:15~0, but are not
limited thereto.
[61] The novel silicon-containing compound represented by formula 1 is chemically and

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thermally stable, is stable to light, and can form a mesomorphic phase (meso-phase) at
a desired temperature range so as to be used suitably for display applications.
[62] The silicon-containing compound represented by formula 1 according to the present
invention may be prepared by a method generally known to one skilled in the art.
According to a preferred embodiment of the present invention, the silicon-containing
compound represented by formula 1 may be prepared by way of the following
Reaction Schemes 1~5.
[63] [Reaction Scheme 1]
[64]

[65] In one embodiment of the method represented by Reaction Scheme 1, a Grignard
reagent is formed from 1,4-dibromobenzene with Mg, followed by a reaction with
4-n-propylcyclohexane and dehydration using TsOH. The resultant product is allowed
to react with n-BuLi to form an anion, which in turn is allowed to react with a silyl
chloride derivative. Next, hydrogenation is performed by using the Raney-Nickel
catalyst in order to form a trans isomer, thereby providing a silyl liquid crystal
compound represented by formula 11. Otherwise, the trans isomer may be formed by
way of hydrbgenation using Pd/charcoal and recrystallization. Herein, the silyl chloride
derivative may be formed according to a method generally known to one skilled in the
art. For example, Mg is added to 1 -bromo-4-fluorobenzene to form a Grignard reagent,
and an excessive amount of Me2SiCl2 is added thereto to provide the silyl chloride
derivative.
[66] [Reaction Scheme 2]
[67]

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[68] In one embodiment of the method represented by Reaction Scheme 2,
4,4'-dibromobiphenyl is subjected to the Grignard reaction, followed by dehydration
using TsOH. Then, the resultant product is converted into an anionic form with n-
BuLi, and then is allowed to react with the silyl chloride derivative. If the reaction with
p-chloranil is used instead of hydrogenation, the silyl liquid crystal compound
represented by formula 12 can be obtained.
[69] [Reaction Scheme 31
[70]

[71] In one embodiment of the method represented by Reaction Scheme 3,
1,4-dibromobenzene and 4-n-propylcyclohexanone are subjected to a coupling reaction
in the presence of Mg to provide a tertiary alcohol, followed by dehydration using
TsOH, thereby providing the starting material. Next, the starting material is converted
into a Grignard reagent by using Mg, and the Grignard reagent is allowed to react with
the silyl chloride derivative. Then, the resultant product is allowed to react with p-
chloranil to provide the silyl liquid crystal compound represented by formula 13.

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[72] [Reaction Scheme 4]
[73]

[74] In one embodiment of the method represented by Reaction Scheme 4,
phenylboronic acid is added to 4-bromo-4'-propylbiphenyl and the reaction mixture is
subjected to a coupling reaction in the presence of Pd(PPh) to provide the triphenyl
compound. Then, a silyl group is introduced to the triphenyl compound by using
magnesium or alkyllithium to provide the silyl liquid crystal compound represented by
formula 14.
[75] [Reaction Scheme 5]
[76]

[77] In one embodiment of the method represented by Reaction Scheme 5,
trans,trans-4-(4-propylcyclohexyl) cyclohexan-1-ol and chlorodimethylphenylsilane
are dissolved in a dry solvent, and the reaction mixture is allowed to react at room
temperature in the presence of a base added thereto to provide the liquid crystal
compound containing a -O-Si- bond, represented by formula 15.
[78] In addition to the compounds obtained by way of the above Reaction Schemes 1~5,
compounds obtained by similar methods or conventional methods known to one skilled
in the art are also included in the scope of the present invention. The silicon-containing

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compounds obtained as described above may be mixed in an adequate ratio to provide
a liquid crystal composition.
[79] The present invention provides a liquid crystal composition, preferably a nematic
liquid crystal composition, which comprises the silicon-containing compound
represented by formula 1.
[80] To provide the desired liquid crystal characteristics by a liquid crystal composition,
about 5~20 components are generally used in combination in the liquid crystal
composition. According to the present invention, it is possible to provide a liquid
crystal composition having a low driving voltage and a fast response time by using the
novel silicon-containing compound represented by formula 1, which can serve to
impart high positive dielectric anisotropy as well as to reduce viscosity.
[81] Although there is no particular limitation in the content of the compound
represented by formula 1, more particularly at least one compound selected from the
group consisting of the silicon-containing liquid crystal compounds represented by
formulae 2~10, each compound is preferably used in an amount of l~50 wt% based on
100 wt% of the total liquid crystal composition.
[82] The liquid crystal composition according to the present invention may further
comprise other liquid crystal compounds, currently used in a conventional liquid
crystal composition, in addition to the silicon-containing compound represented by
formula 1. Such compounds may be used in a controlled ratio, as necessary. Ad-
ditionally, suitable additives may also be used, and such additives are disclosed in [H.
Kelker/R. Hatz, Handbook of Liquid Crystals, Verlag Chemie, Weinheim, 1980]. For
example, additives for modifying the dielectric anisotropy, viscosity and/or alignment
of a nematic phase may be used. Particular examples of the additives that may be used
in the liquid crystal composition according to the present invention include chiral
dopants that inhibit the helical structure and reverse distortion of a liquid crystal,
dichroic dyes, or the like.
[83] The liquid crystal composition according to the present invention may be prepared
by a method generally known to one skilled in the art. In one embodiment of such
methods, various components that form the liquid crystal composition are dissolved at
a temperature ranging from room temperature to a high temperature.
[84] Also, the present invention provides a liquid display device, which comprises a
liquid crystal layer obtained from the liquid crystal composition.
[85] There is no particular limitation in the liquid crystal display device. Particular
examples of the liquid crystal display device include a simple matrix type twist
nematic liquid crystal display device, simple matrix type supertwist nematic liquid
crystal display device, active matrix type TFT (thin film transistor) liquid crystal
display device, active matrix type MIM (metal insulator metal) liquid crystal display

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device, active matrix type IPS (in-plane switching) liquid crystal device, or the like.
[86] The liquid crystal display device according to the present invention may be man-
ufactured by a method generally known to one skilled in the art One embodiment of
such methods, a liquid crystal composition is dissolved at a suitable temperature, and
then introduced into a liquid crystal device. The liquid crystal phase, dissolved as
mentioned above, may be modified so that it can be applied for all types of liquid
crystal display devices by virtue of the use of suitable additives.
Mode for the Invention
[87] Reference will now be made in detail to the preferred embodiments of the present
invention. It is to be understood that the following examples are illustrative only and
the present invention is not limited thereto.
[88] [Examples 1-17]
[89] Example 1
[90]

[91] First, 25 ml of dichlorodimetylsilane was added to 50 ml of dry THF, and 100 ml of
1.0M 4-fluorophenylmagnesium bromide was added very slowly dropwise thereto.
After the completion of the addition, the reaction mixture was stirred at low
temperature for about 3 hours. Next, an excessive amount of hexane was added to the
reaction mixture in order to precipitate a magnesium salt. The magnesium salt was
removed via filtration and the organic solvent was evaporated completely under
reduced pressure, Then, chloro-dimethyl(4-fluorophenyl)silane was separated off via
vacuum distillation (70~75°C/8mPa). In a separate container, 255 mg of Mg was
dissolved in 10 ml of dry THF. Next, a solution containing 2.88g of
4-bromo-4'-n-propylbiphenyl dissolved in 20 ml of dry THF was added thereto to form
a Grignard reagent, to which 1.97 g of chlorodimethyl(4-fluorophenyl)silane was
added at room temperature. After stirring for about 10 hours, the reaction mixture was
worked up with water and hexane, and then purified by silica gel column chro-
matography to obtain the silicon-containing compound represented by the above
formula (yield: 88%). 400MHz 'H-NMR, CDC13, δ(ppm): 0.57 (s, 6H), 0.99 (t, 3H),
1.65-1.69 (m, 2H), 2.64 (t, 2H), 7.07 (t, 2H), 7.25 (d, 2H), 7.54 (d, 2H), 7.58-7.61 (m,
6H).
[92] Example 2
[93]

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[94] First, 2.0 g of trans, trans-cyclohexanol was dissolved in 20 ml of CH2Cl2, and 1.7 g
of chloro-dimethylphenylsilane and 1.08 g of triethylamine was added thereto at room
temperature. After stirred for about 10 hours, the reaction mixture was worked up with
water and CH2Cl2, and then purified by silica gel column chromatography to obtain the
silicon-containing compound represented by the above formula (yield: 78%). 400MHz
'H-NMR, CDC13, 8(ppm): 0.38 (s, 6H), 0.86-0.90 (m, 2H), 0.91 (t, 3H), 0.93-1.09
(m, 6H), 1.09-1.20 (m, 3H), 1.25-1.38 (m, 4H), 1.63-1.71 (br, 4H), 1.71-1.76 (br,
2H), 1.81-1.90 (br, 2H), 3.51 (m, 1H), 7.36-7.40 (m, 3H), 7.59-7.62 (m, 2H).
[95] Example 3
[96]

[97] First, 6.45 g of dichlorodimethylsilane was dissolved in dry THF and cooled to 0°C.
Next, 100 ml of 4-fluorobenzylmagnesium chloride (0.25M) was slowly added
dropwise thereto. After the completion of the addition, the reaction mixture was
allowed to further react at low temperature for about 3 hours. Next, an excessive
amount of hexane was added to the reaction mixture to precipitate a magnesium salt.
The magnesium salt was removed via filtration and the organic solvent was evaporated
under reduced pressure. By doing so, chlorodimethyl(4-fluorophenyl)silane was
obtained with a yield of 80% via vacuum distillation. In a separate container, 3.0 g of
4-bromo-4'-n-propylbiphenyl and 250 mg of Mg was added to 20 ml of dry THF to
provide a Grignard reagent, to which 2.3 g of chlorodimethyl(4-fluorophenyl)silane
was added at room temperature. The reaction mixture was heated to 60°C for about 10
hours, and worked up with water and hexane, and then purified by silica gel column
chromatography to obtain the silicon-containing compound represented by the above
formula (yield: 91%). 400MHz 1H-NMR, CDCT, 8(ppm): 0.30 (s, 6H), 0.99 (t, 3H),
1.65-1.74 (m, 2H), 2.30 (s, 2H), 2.65 (t, 2H), 6.89 (d, 4H), 7.26-7.28 (m, 2H), 7.50 (d,
2H), 7.54 (d, 2H), 7.58 (d, 2H).
[98] Example 4
[99]


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[100] First, 3.03 g of 4-bromo-4'-n-pentylbiphenyl and 245 mg of Mg was introduced into
20 ml of dry THF to form a Grignard reagent, and then 2.05 g of chloro-
dimethyl(4-fluorobenzyl)silane was added thereto. The reaction mixture was heated to
60°C for about 10 hours, and worked up with water and hexane, and then purified by
silica gel column chromatography to obtain the silicon-containing compound
represented by the above formula (yield: 94%). 400MHz 'H-NMR, CDC1,6(ppm):
0.31 (s, 6H), 0.91-0.97 (m, 3H), 136-1.45 (m, 4H), 1.65-1.77 (m, 2H), 2.33 (s, 2H),
2.69 (t, 2H), 6.91 (d, 4H), 7.27-7.32 (m, 2H), 7.53 (d, 2H), 7.56 (d, 2H), 7.61 (d, 2H).
[101] Example 5
[102]

[103] First, 6.45 g of dichlorodimethylsilane was dissolved in dry THF and cooled to 0°C.
Next, 25 mmol of 3,4,5-trifluorobenzylmagnesium chloride was added slowly
dropwise thereto. After the completion of the addition, the reaction mixture was
allowed to further react at low temperature for about 3 hours. Next, an excessive
amount of hexane was added to the reaction mixture to precipitate a magnesium salt.
The magnesium salt was removed via filtration and the organic solvent was evaporated
under reduced pressure. By doing so, chlorodimethyl(3,4,5-trifluoroben2ylsilane) was
obtained with a yield of 75% via vacuum distillation. In a separate container, 2.75 g of
4-bromo-4/-n-propylbiphenyl and 245 mg of Mg was added to 20 ml of dry THF to
provide a Grignard reagent, to which 2.4 g of chlorodim
ethyl(3,4,5-trifluorobenzyl)silane was added at room temperature. The reaction
mixture was heated to 60°C for about 10 hours, and worked up with water and hexane,
and then purified by silica gel column chromatography to obtain the silicon-containing
compound represented by the above formula (yield: 87%). 400MHz 'H-NMR, CDCl3 ,
5(ppm): 0.31 (s, 6H), 0.99 (t, 3H), 1.63-1.76 (m, 2H), 2.26 (s, 2H), 2.64 (t, 2H),
6.46-6.54 (m, 2H), 7.26 (d, 2H), 7.48 (d, 2H), 7.53 (d, 2H), 7.59 (d, 2H).
[104] Example 6

[106] First, 3.03 g of 4-bromo-4'-n-pentylbiphenyl and 245 mg of Mg was introduced into
20 ml of dry THF to form a Grignard reagent, and then 2.4 g of
[105]

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chlorodimethyl(3,4,5-trifluorobenzyl)silane was added thereto. The reaction mixture
was heated to 60°C for about 10 hours, and worked up with water and hexane, and then
purified by silica gel column chromatography to obtain the silicon-containing
compound represented by the above formula (yield: 85%). 400MHz 'H-NMR, CDCl3 ,
5(ppm): 0.35 (s, 6H), 0.93-0.98 (m, 3H), 1.33~1.48 (m, 4H), 1.65~1.77 (m, 2H), 2.29
(s, 2H), 2.68 (t, 2H), 6.50-6.59 (m, 2H), 7.32 (d, 2H), 7.52 (d, 2H), 7.58 (d, 2H), 7.63
(d,2H).
[107] Example 7
[108]

[109] First, 2.32 g of 3,5-difluoro-4'-n-propylbiphenyl was added to 20 ml of dry THF,
and 5 ml of 2.0M LDA was added dropwise thereto at -78°C. The reaction mixture was
allowed to react sufficiently at low temperature for about 3 hours to form an anion.
Next, 2.05 g of chlorodimethyl(4-fluorobenzyl)silane was added thereto, and the
reaction mixture was warmed gradually to room temperature. After stirred at room
temperature for about 1 hour, the reaction mixture was worked up with water and
hexane, and then purified by silica gel column chromatography to obtain the silicon-
containing compound represented by the above formula (yield: 90%). 400MHz H-
NMR, CDC13,6(ppm): 0.35 (s, 6H), 0.98 (t, 3H), 1.64-1.74 (m, 2H), 2.43 (s, 2H),
2.65 (t, 2H), 6.87-6.97 (m, 4H), 7.05 (d, 2H), 7.28 (d, 2H), 7.50 (d, 2H).
[110] Example 8
[111]

[112] First, 2.60 g of 3,5-difluoro-4'-n-pentylbiphenyl was added to 20 ml of dry THF,
and 5 ml of 2.0M LDA was added dropwise thereto at -78°C. The reaction mixture was
allowed to react sufficiently at low temperature for about 3 hours to form an anion.
Next, 2.05 g of chlorodimethyl(4-fluorobenzyl)silane were added thereto, and the
reaction mixture was warmed gradually to room temperature. After stirred at room
temperature for about 1 hour, the reaction mixture was worked up with water and
hexane, and then purified by silica gel column chromatography to obtain the silicon-
containing compound represented by the above formula (yield: 85%). 400MHz] H-
NMR, CDC13,8(ppm) : 0.35 (s, 6H), 0.91-0.93 (m, 3H), 1.31-1.43 (m, 4H), 1.60-1.73

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(m, 2H), 2.42 (s, 2H), 2.65 (t, 2H), 6.86-6.98 (m, 4H), 7.05 (d, 2H), 7.28 (d, 2H), 7.49
(d,2H).
[113] Example 9
[114]

[115] First, 2.32 g of 3,5-difluoro-4'-n-propylbiphenyl was added to 20 ml of dry THF,
and 5 ml of 2.0M LDA was added dropwise thereto at -78°C. The reaction mixture was
allowed to react sufficiently at low temperature for about 3 hours to form an anion.
Next, 2.4 g of chlorodimethyl(3,4,5-trifluorobenzyl)silane were added thereto, and the
reaction mixture was wanned gradually to room temperature. After stirred at room
temperature for about 1 hour, the reaction mixture was worked up with water and
hexane, and then purified by silica gel column chromatography to obtain the silicon-
containing compound represented by the above formula (yield: 84%). 400MHz 1H-
NMR, CDC13, 6(ppm) : 0.44 (s, 6H), 1.04 (t, 3H), 1.69-1.79 (m, 2H), 2.45 (s, 2H),
2.70 (t, 2H), 6.60-6.68 (m, 2H), 7.11 (d, 2H), 7.34 (d, 2H), 7.55 (d, 2H).
[116] Example 10
[117]

[118] First, 2.6 g of 3,5-difluoro-4'-n-pentylbiphenyl was added to 20 ml of dry THF, and
5 ml of 2.0M LDA was added dropwise thereto at -78°C. The reaction mixture was
allowed to react sufficiently at low temperature for about 3 hours to form an anion.
Next, 2.4 g of chlorodimethyl(3,4,5-trifluoroben2yl)silane was added thereto, and the
reaction mixture was warmed gradually to room temperature. After stirred at room
temperature for about 1 hour, the reaction mixture was worked up with water and
hexane, and then purified by silica gel column chromatography to obtain the silicon-
containing compound represented by the above formula (yield: 80%). 400MHz H-
NMR, CDC13, 5(ppm) : 0.40 (s, 6H), 0.85-0.96 (m, 3H), 1.31-1.42 (m, 4H), 1.61
-1.72 (m, 2H), 2.40 (s, 2H), 2.64 (t, 2H), 6.55-6.62 (m, 2H), 7.05 (d, 2H), 7.28 (d,
2H), 7.49 (d, 2H).
[119] Example 11
[120]

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[121] First, 3.0 g of 4-bromo-4'-n-propylbiphenyl was dissolved into 27 ml of DME as a
solvent. Next, 2.05 g of 3,5-difluorophenylboronic acid, 380 mg of Pd(PPh ) and 27
ml of 2.0M Na2CO3 was added thereto. After refluxed at 100°C for about 10 hours, the
reaction mixture was worked up with water and hexane, and purified by silica gel
column chromatography to obtain the triphenyl compound with a yield of 95%. Then,
3.0 g of the triphenyl compound was dissolved into 20 ml of dry THF and 5 ml of
2.0M LDA was slowly added dropwise thereto at -78°C. After an anion was formed
over about 3 hours, 1.3 g of trimethylsilyl chloride was added to the anion at low
temperature and the reaction mixture was warmed gradually to room temperature.
After stirred at room temperature for about 1 hour, the reaction mixture was worked up
with water and hexane, and then recrystallized from hexane/MeOH solvent to obtain
the silicon-containing compound represented by the above formula (yield: 95%).
400MHz 1H-NMR, CDC13, 5(ppm) : 0.41 (s, 9H), 0.99 (t, 3H), 1.66-1.75 (m, 2H), 2.65
(t, 2H), 7.09 (d, 2H), 7.28 (d, 2H), 7.56 (d, 2H), 7.63 (d, 2H), 7.68 (d, 2H).
[122] Example 12
[123]

[124] First, 3.3 g of 4-bromo-4'-n-pentylbiphenyl was dissolved into 27 ml of DME as a
solvent. Next, 2.05 g of 3,5-difluorophenylboronic acid, 380 mg of Pd(PPh ) and 27
ml of 2.0M Na2CO3was added thereto. After refluxed at 100°C for about 10 hours, the
reaction mixture was worked up with water and hexane, and then purified by silica gel
column chromatography to obtain the triphenyl compound with a yield of 90%. Then,
3.0 g of the triphenyl compound was dissolved into 20 ml of dry THF and 4.5 ml of
2.0M LDA was slowly added dropwise thereto at -78°C. After an anion was formed ov
er about 3 hours, 1.16 g of trimethylsilyl chloride was added to the anion at low
temperature and the reaction mixture was warmed to room temperature. After stirred at
room temperature for about 1 hour, the reaction mixture was worked up with water and
hexane, and then recrystallized from hexane/MeOH solvent to obtain the silicon-
containing compound represented by the above formula (yield: 92%). 400MHz' H-
NMR, CDC1,5(ppm) : 0.41 (s, 9H), 0.87-0.95 (m, 3H), 1.31-1.42 (m, 4H), 1.63-1.72
(m, 2H), 2.67 (t, 2H), 7.09 (d, 2H), 7.28 (d, 2H), 7.56 (d, 2H), 7.63 (d, 2H), 7.68 (d,

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2H).
[125] Example 13
[126]

[127] First, 3.9 g of 3,5-difluoro-4-iodo-4'-n-propylbiphenyl was dissolved into 27 ml of
DME as a solvent. Next, 2.05 g of 3,5-difluorophenylboronic acid, 380 nig of Pd(PPh )
and 27 ml of 2.0M Na2CO3was added thereto. After refluxed at 1000C for about 10
hours, the reaction mixture was worked up with water and hexane, and then purified by
silica gel column chromatography to obtain the triphenyl compound with a yield of
98%. Then, 3.4 g of the triphenyl compound was dissolved into 20 ml of dry THF and
5 ml of 2.0M LDA was slowly added dropwise thereto at -78°C. After an anion was
formed over about 3 hours, 1.2 g of trimethylsilyl chloride was added to the anion at
low temperature and the reaction mixture was warmed gradually to room temperature.
After stirred at room temperature for about 1 hour, the reaction mixture was worked up
with water and hexane, and then recrystallized from hexane/MeOH solvent to obtain
the silicon-containing compound represented by the above formula (yield: 96%).
400MHz ]H-NMR, CDC13, 5(ppm) : 0.42 (s, 9H), 0.99 (t, 3H), 1.65-1.75 (m, 2H), 2.66
(t, 2H), 7.00 (d, 2H), 7.23 (d, 2H), 7.30 (d, 2H), 7.52 (d, 2H).
[128] Example 14
[129]

[130] First, 4.2 g of 3,5-difluoro-4-iodo-4'-n-pentylbiphenyl was dissolved into 27 ml of
DME as a solvent. Next, 2.05 g of 3,5-difluorophenylboronic acid, 380 mg of Pd(PPh)
and 27 ml of 2.0M Na CO was added thereto. After refluxed at 100°C for about 10
hours, the reaction mixture was worked up with water and hexane, and then purified by
silica gel column chromatography to obtain the triphenyl compound with a yield of
93%. Then, 3.7 g of the triphenyl compound was dissolved into 20 ml of dry THF and
5 ml of 2.0M LDA was added slowly dropwise thereto at -78°C. After an anion was
formed over about 3 hours, 1.19 g of trimethylsilyl chloride was added to the anion at
low temperature and the reaction mixture was warmed to room temperature. After
stirred at room temperature for about 1 hour, the reaction mixture was worked up with
water and hexane, and then recrystallized from hexane/MeOH solvent to obtain the
silicon-containing compound represented by the above formula (yield: 92%). 400MHz

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'H-NMR, CDC13,6(ppm): 0.42 (s, 9H), 0.85-0.94 (m, 3H), 1.33-1.41 (m, 4H),
1.62-1.70 (m, 2H), 2.67 (t, 2H), 6.99 (d, 2H), 7.22 (d, 2H), 7.29 (d, 2H), 7.51 (d, 2H).
[131] Example 15. Liquid Crystal Composition (1)
[132] A liquid crystal composition was prepared from the materials as shown in the
following Table 1. In Table 1, each percent ratio refers to parts by weight per hundred
parts of composition.
[133] [Table 1]
[134]

[135] Example 16. Liquid Crystal Composition (2)
[136] A liquid crystal composition was prepared from the materials as shown in the

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following Table 2. In Table 2, each percent ratio refers to parts by weight per hundred
parts of composition.
[137] [Table 2]

[138]
[139] Example 17. Liquid Crystal Composition (3)
[140] A liquid crystal composition was prepared from the materials as shown in the
following Table 3. la Table 3, each percent ratio refers to parts by weight per hundred
parts of composition.
[141] [Table 3]
[142]

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Composition
[ 145] The liquid crystal compositions according to the present invention were evaluated
for their physical properties according to the following test.
[146] The liquid crystal compositions according to Examples 15~17 were used. Each
composition was introduced into a test tube in an amount of 1 g under the nitrogen
atmosphere, and then heated at 150°C for 2 hours to measure the phase transition
temperature. Herein, clearing point (c.p.) of each composition refers to the isotropic
liquid phase transition temperature in a nematic phase. Additionally, optical anisotropy
(An) of each composition was measured at 20°C/589 nm, while dielectric anisotropy
(Ae) of each composition was measured at 20°C/l kHz. Also, viscosity of each
composition was measured at 20°C. The results are shown in the following Table 4.
[147] After the test, it can be seen that the liquid crystal compositions according to
Examples 15~17 that comprise, as an active component, the novel silicon-containing
compound represented by formula 1 according to the present invention, show high
positive (+) dielectric anisotropy and low viscosity (see Table 4).
[148] [Table 4]
[149]

Ex. Clearing Optical Dielectric Viscosity
point (*C ) anisotropy anisotropy (niPas)
IS 88 0.107 11.1 118
16 85 O.089 10.2 95
17 97 0.115 11.9 124
Industrial Applicability
[150] As can be seen from the foregoing, the present invention provides a novel nematic
liquid crystal compound, which has low viscosity and high positive dielectric
anisotropy, and a liquid crystal composition comprising the same compound.
According to the present invention, it is possible to provide a liquid crystal display
device that satisfies various desired characteristics, including a fast response time and a
low driving voltage.
[151] While this invention has been described in connection with what is presently
considered to be the most practical and preferred embodiment, it is to be understood
that the invention is not limited to the disclosed embodiment and the drawings. On the
contrary, it is intended to cover various modifications and variations within the spirit
and scope of the appended claims.

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Claims
[1 ] A silicon-containing compound represented by the following formula 1:
[Formula 1]

wherein the substituents, which are introduced into ring B, ring C or ring D and
represented by L1to L7, are independent from each other, even if they have the
same designations;

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M is selected from C, N and Si, with the proviso that if M is N, L or L is null;
Z is C;
each of a, a and a is independently selected from C, NR and O;
E is selected from the group consisting of SiMe2Ok2 (CQ2)n2 , SiEt2Ok2(CQ2)n2 , SiF2
Ok2(CQ2)n2,SiCl2Ok2(CQ2)n2,SiMe2(CQ2)n2Ok2,SiEt2(CQ2)n2Ok2,SiF2(CQ2)n2Ok2,
SiCl2(CQ2)n2Ok2,Ok2 SiMe2(CQ2)n2,Ok2 SiEt2(CQ2)n2,Ok2SiF2(CQ2)n2,Ok2SiCl2(CQ2
)n2, (CQ2)n2Ok2SiMe2, (CQ2)n2Ok2SiEt2, (CQ2)n2Ok2SiF2, (CQ2)n2Ok2SiCl2,Ok2(CQ2)
n2SiMe2,Ok2(CQ2)n2SiEt2,Ok2(CQ2) SiF2Ok2(CQ2)n2SiCl2,(CQ2)n2SiMe2Ok2,(CQ
2)n2SiEt2Ok2,(CQ2)n2SiF2Ok2,(CQ2)n2SiCI2Ok2,(CH2)n2, C≡C, O, S, COO, OCO,
CF2O, OCF2, OCOO, CH2O, CH2CO, OCH2 and COCH2, wherein k is 0 or 1, Q
is H or F, and n is an integer between 0 and 3;
R is selected from the group consisting of H, a C1 ~C15 alkyl group, a C2 ~C15
alkene group and an alkoxy group (R1O), wherein the alkene group is CH=CH2,
CH=CHCH3 (E,Z), CH2CH=CH2, CH=CHCH2CH3 (E,Z), CH2CH=CHCH3
(E,Z), CH2CH2CH=CH2, CH=CHCH2CH2CH3 (E^), CH2CH=CHCH2CH3 (E,Z),
CH2CH2CH=CHCH3(E,Z) or CH2CH2CH2CH=CH2;
R is selected from the group consisting of H, a C1 ~C15 alkyl group and a C2 ~C15
alkene group, wherein the alkene group is CH=CH2, CH=CHCH3 (E,Z), CH2
CH=CH2, CH=CHCH2CH3 (E,Z), CH2CH=CHCH3 (E,Z), CH2CH2CH=CH2,
CH=CHCH2CH2CH3 (E,Z), CH2CH=CHCH2CH3(E,Z), CH2CH2CH=CHCH3
(E,Z) or CH2CH2CH2CH=CH2;
X is selected from the group consisting of H, SiR2R3R4, CF3, OCF3, CN, NCS,
halogen atoms and R;
each of R2, R3 and R4 is independently selected from R and halogen atoms;
each of L1, L2, L 3, L4, L5, L6 and L7 is lndependently selected from the group
consisting of H, halogen atoms, CN, CF3, OCF3 and NCS;
each of o, p and q independently represents an integer between 0 and 2; and
at least one of E, A and X contains silicon.
[2] The silicon-containing compound according to claim 1, which has zero (0) or
positive dielectric anisotropy.
[3] The silicon-containing compound according to claim 1, which is a compound
represented by any one formula selected from the group consisting of formula
2~formula 10:
[Formula 2]

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WO 2006/075883 PCT/KR2006/000132

wherein A is selected from the group consisting of SiMe2Ok1 (CQ2)n1, SiEt2Ok1
(CQ2)n1 , SiF2Ok1 (CQ2)n1 , SiCl2Ok1 (CQ2)n1, SiMe2 (CQ2)n1Ok1, SiEt2 (CQ2)n1Ok1, SiF2
(CQ2)n1Ok1,SiCl2 (CQ2)n1Ok1,Ok1 SiMe2(CQ2)n1,Ok1 SiEt2(CQ2)n1,Ok1SiF2(CQ2)n1,O
k1SiCl2 (CQ2)n1, (CQ2)n1 Ok1 SiMe2 , (CQ2)n1 Ok1 SiEt2, (CQ2)n1 Ok1 SiF2, (CQ2)n1Ok1 SiCl
2,Ok1 (CQ2)n1 SiMe2,Ok1 (CQ2)n1 SiEt2,Ok1 (CQ2)n1 SiF2,Ok1 (CQ2)n1 SiCl2,(CQ2)n1
SiMe2Ok1, (CQ2)n1SiEt2Ok1 , (CQ2)n1 SiF2Ok1, (CQ2)n1 SiCl2Ok1 , (CH2)n1, CH=CH,
C≡C, O, S, COO, OCO, CF2O, OCF2, OCOO, CH2O, CH2CO, OCH2 and COCH
2, wherein k1 is 0 or 1, Q is H or F, n1 is an integer between 0 and 3;
M is C, N or Si, with the proviso that if M is N, L3 or L7 is null;
Z is C;
each of a, a and a is independently selected from C, NR and O;

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E is selected from the group consisting of SiMe2Ok2 (CQ2) n2,SiEt2Ok2 (CQ2)n2,SiF2
Ok2(CQ2)n2,SiCl2Ok2(CQ2)n2,SiMe2(CQ2)n2Ok2, SiEt2(CQ2)n2Ok2, SiF2(CQ2)n2Ok2,
SiCl2 (CQ2)n2Ok2, Ok2SiMe2(CQ2)n2,Ok2 SiEt2 (CQ2)n2,Ok2SiF2(CQ2)n2, Ok2SiCl2 (CQ2
)n2,(CQ2)n2Ok2SiMe2,(CQ2)n2Ok2SiEt2,(CQ2)n2Ok2SiF2,(CQ2)n2O SiCl2,Ok2(CQ2)
n2SiMe2, Ok2(CQ2)n2SiEt2, Ok2(CQ2)n2SiF2, Ok2(CQ2)n2SiCl2, (CQ2)n2SiMe2Ok2, (CQ
2)n2SiEt2Ok2, (CQ2)n2SiF2Ok2' (CQ2)n2SiCl2Ok2, )CH2)n2, C≡C,O,S,COO,OCO,
CF2O, OCF2, OCOO, CH2O, CH2CO, OCH2 and COCH2, wherein k is 0 or 1, Q
is H or F, and n is an integer between 0 and 3;
R is selected from the group consisting of H, a C1 ~C15 alkyl group, a C2 ~C15
alkene group and an alkoxy group (R1O), wherein the alkene group is CH=CH2,
CH=CHCH3 (E,Z), CH2CH=CH2, CH=CHCH2CH (E,Z), CH2CH=CHCH3
(E,Z), CH2CH2CH=CH2, CH=CHCH2CH2CH3 (E,Z), CH2CH=CHCH2CH3 (E,Z),
CH2CH2CH=CHCH3 (E,'Z) or CH2CH2CH2CH=CH2;
R is selected from the group consisting of H, a C1 ~C15 alkyl group and a C2 ~C15
alkene group, wherein the alkene group is CH=CH2, CH=CHCH3 (E,Z), CH2
CH=CH2, CH=CHCH2CH3 (E,Z), CH2CH=CHCH3 (E,Z), CH2CH2CH=CH2,
CH=CHCH2CH2CH3(E,Z), CH2CH=CHCH2CH3(E,Z), CH2CH2CH=CHCH3
(E,Z) or CH2CH2CH2CH=CH2;
X is selected from the group consisting of H, SiR2R3R4 , CF3, OCF3, CN, NCS,
halogen atoms and R;
each of R2, R3 and R4 is independently selected from R and halogen atoms;
each of L1,L2,L3,L4,L5,L6 and L7 is independently selected from the group
consisting of H, halogen atoms, CN, CF3, OCF3 and NCS; and
each of o, p and q independently represents an integer between 0 and 2.
[4] The silicon-containing compound according to claim 1, which is selected from
the group consisting of the following compounds:


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WO 2006/075883 PCT/KR2006/000132

wherein A is selected from the group consisting of SiOk1(CQ2)n1,Si(CQ2)n1Ok1,
(CQ2)n1Ok1Si, (CQ2)n1SiOk1,Ok1(CQ2)n1Si and Ok1Si(CQ2)n1, and R, R2, R3, R4, M,
a1,a2,a3,L1,L2,L3,L4,L5,L6 and X are the same as defined in claim 1.
[5] The silicon-containing compound as claimed in claim 1, which has
stereoisomers.
[6] The silicon-containing compound as claimed in claim 5, wherein the
stereoisomers of the silicon-containing compound are present in a ratio of trans-
isomencis-isomer of 85~100:15~0.
[7] A liquid crystal composition, which comprises at least one silicon-containing
compound as defined in any one of claims 1 to 6.
[8] The liquid crystal composition as claimed in claim 7, wherein each silicon-
containing compound is present in an amount of 1 ~50 wt% based on 100 wt% of
the total weight of the composition.
[9] A liquid crystal display device, which comprises a liquid crystal layer prepared
from the liquid crystal composition as defined in claim 7.
[10] A method for preparing a silicon-containing compound, which is represented by
the following Reaction Scheme 1:
[Reaction Scheme 1]


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W is selected from Me, Et, F and Cl; and
ring B, ring C, ring D, R, E, X, o, p and q are the same as defined in claim 1.
[11] A method for preparing a silicon-containing compound, which is represented by
the following Reaction Scheme 2:
[Reaction Scheme 2]

wherein V is selected from the group consisting of H, Me, Et, F, Cl, OMe and
OEt; and
ring B, ring C, E, R, L, L, o, p and q are the same as defined in claim 1.
[12] A method for preparing a silicon-containing compound, which is represented by
the following Reaction Scheme 3:
[Reaction Scheme 3]

wherein U is selected from SiOk1 (CQ2)n1,Si(CQ2)n1Ok1,(CQ2)n1Ok1Si, and(CQ2)
SiOk1 , wherein k1 is 0 or 1, Q is H or F, and n is an integer between 0 and 3;
W is selected from Me, Et, F and Cl; and
ring B, ring C, ring D, R, E, X, o, p and q are the same as defined in claim 1.
[13] A method for preparing a silicon-containing compound, which is represented by
the following Reaction Scheme 4:
[Reaction Scheme 4]

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WO 2006/075883 PCT/KR2006/000132

wherein V is selected from the group consisting of H, Me, Et, F, Cl, OMe and
OEt; and
ring B, R, E, L1 , L2 , L4 , L5 , o, p and q are the same as defined in claim 1.
[14] A method for preparing a silicon-containing compound, which is represented by
the following Reaction Scheme 5:
[Reaction Scheme 5]

31
(54) Title: LIQUID CRYSTAL COMPOSITION COMPRISING NOVEL SILICON CONTAINING COMPOUNDS AND LIQ-
UID CRYSTAL DISPLAY DEVICE USING THE SAME
(57) Abstract: Disclosed are a silicon-containing compound, a liquid crystal composition comprising the same compound, and a
liquid crystal display device comprising a liquid crystal layer prepared from the liquid crystal composition. The silicon-containing
compound, which forms the liquid crystal composition, has low viscosity and high positive dielectric anisotropy. Therefore, it is
possible to provide a liquid crystal display device, which has a fast response time and can be driven at a low voltage.