LIQUID CRYSTAL COMPOUNDS OF CYCLOALKYL-CONTAINING DIBENZOFURAN DERIVATIVES, PREPARATION METHOD THEREFOR AND USE THEREOF

Abstract

Disclosed are liquid crystal compounds of cycloalkyl-containing dibenzofuran derivatives, a preparation method therefor and use thereof. The compounds are as represented by formula I. In the molecular structures of the compounds of formula I provided by the present invention, liquid crystal compounds of cycloalkyl terminal group-containing dibenzofuran derivatives, compared with those having flexible alkyl chains as terminal groups, exhibit better intersolubility, and thus the use of a compound as represented by formula I provided by the present invention can improve the intersolubility of a liquid crystal compound and extend the application range of a liquid crystal mixture, producing an important application value.

##STR00001##

Claims

1. Compounds as represented by formula I ##STR00151## wherein H represents one of cyclopropyl, cyclobutyl, cyclopentyl or 2-tetrahydrofuranyl; Z represents one of a single bond, CH.sub.2, O, CH.sub.2CH.sub.2 or CH.sub.2O; and X represents a hydrogen atom, a fluorine atom, an alkyl group having 1-7 carbon atoms or an alkoxy group having 1-7 carbon atoms.

2. The compounds according to claim 1, wherein the compounds as represented by said formula I are specifically compounds as represented by formulas I1 to I15: ##STR00152## ##STR00153## wherein H each independently represents one of cyclopropyl, cyclobutyl or 2-tetrahydrofuranyl; and R each independently represents one of an alkyl group having 1-7 carbon atoms or an alkoxy group having 1-7 carbon atoms.

3. The compounds according to claim 1, wherein the compounds as represented by said formula I are specifically the following compounds as represented by I1-1 to I15-2: ##STR00154## ##STR00155##

4. A liquid crystal medium, wherein said liquid crystal medium comprises one or more compounds as represented by formula I in claim 1.

5. The liquid crystal medium according to claim 4, wherein said liquid crystal medium further comprises one or more compounds as represented by formula IV: ##STR00156## in said formula IV, R.sub.2 and R.sub.3 each independently represent any one of groups as shown by (1) to (3) below: (1) linear alkyl groups having 1-7 carbon atoms or linear alkoxy groups having 1-7 carbon atoms; (2) groups formed by substituting one or more CH.sub.2 in any one of the groups as shown by (1) with O, COO, OOC or CHCH; and (3) groups formed by substituting one or more H in any one of the groups as represented by (1) with F, Cl, CHCH.sub.2 or CHCHCH.sub.3; rings B, C, D and E each independently represent the following groups: ##STR00157## and at least one of said rings B, C, D and E is selected from ##STR00158## m, n and o each independently represent 0 or 1; Z.sub.1, Z.sub.2 and Z.sub.3 each independently represent a single bond, C.sub.2H.sub.4, CHCH, , COO, OOC, CH.sub.2O, OCH.sub.2, CF.sub.2O or OCF.sub.2; wherein additionally, any H atom of these groups may be replaced with F.

6. The liquid crystal medium according to claim 5, wherein said liquid crystal medium further comprises one or more compounds as represented by formula V: ##STR00159## in said formula V, R.sub.4 and R.sub.5 each independently represent an alkyl group having 1-10 carbon atoms or an alkenyl group having 2-10 carbon atoms; in addition, any CH.sub.2 of these groups may be replaced with CH.sub.2O, OCH.sub.2 or CC, and any hydrogen may be replaced with F; rings F, G, I and J each independently represent the following groups: ##STR00160## p, q and r each independently represent 0 or 1; Z.sub.4, Z.sub.5 and Z.sub.6 each independently represent a single bond, C.sub.2H.sub.4, CHCH, , COO, OOC, CH.sub.2O, OCH.sub.2, CF.sub.2O, or OCF.sub.2; wherein additionally, any H atom of these groups may be replaced with F.

7. The liquid crystal medium according to claim 6, wherein in said liquid crystal medium, the total content in weight percentage of one or more compounds as represented by formula I is 1-24%, the total content in weight percentage of one or more compounds as represented by formula IV is 35-58%, and the total content in weight percentage of one or more compounds as represented by formula V is 30-46%.

8. The liquid crystal medium according to claim 5, wherein said one or more compounds as represented by formula IV are one or more of the compounds as represented by formulas IVa- to IVo: ##STR00161## ##STR00162## wherein R.sub.2 and R.sub.3 each independently represent any one of groups as shown by (1) to (3) below: (1) linear alkyl groups having 1-7 carbon atoms or linear alkoxy groups having 1-7 carbon atoms; (2) groups formed by substituting one or more CH.sub.2 in any one of the groups as shown by (1) with O, COO, OOC or CHCH; and (3) groups formed by substituting one or more H in any one of the groups as represented by (1) with F, Cl, CHCH.sub.2 or CHCHCH.sub.3; ##STR00163## each independently represent any one of the following groups: ##STR00164##

9. The liquid crystal medium according to claim 6, wherein said one or more compounds as represented by formula V are one or more of the compounds as represented by formulas Va- to Vp: ##STR00165## ##STR00166## wherein R.sub.4 and R.sub.5 each independently represent an alkyl group having 1-10 carbon atoms or an alkenyl group having 2-10 carbon atoms; in addition, any CH.sub.2 of these groups may be replaced with CH.sub.2O, OCH.sub.2 or CC, and any hydrogen may be replaced with F; (F) each independently represents F or H.

10. Use of any one or more compounds of claim 1 in the preparation of a liquid crystal mixture, a liquid crystal display device material or an electro-optical display device material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The FIGURE is a mass spectrum of the compound as represented by formula I12-1.

DETAILED DESCRIPTION OF EMBODIMENTS

[0044] The present invention is further described in conjunction with particular examples below, and the present invention is not limited to the following examples. Said methods are all conventional methods, unless otherwise specified. Said raw materials, unless otherwise specified, are commercially available. In the following examples, GC represents a gas chromatographic purity, MP represents a melting point, CP represents a clearing point, MS represents mass spectrum, represents dielectric anisotropy, and n represents optical anisotropy. Methods for the determination of GC, MP, CP, MS, and n are all conventional methods.

Example 1. Compound as Represented by Formula I1-1

[0045] ##STR00022##

[0046] Step 1

##STR00023##

[0047] 45 g (0.21 mol) of 2-fluoro-4-bromocyclopropylbenzene and 150 mL of tetrahydrofuran are added into a 1 L three-necked flask, stirring is started, nitrogen is charged to replace air, the flask is placed in a cryostat and cooled with liquid nitrogen, when the temperature is decreased to 78 C., 200 ml (0.23 mol) of a solution of 2.5 M diisopropylamine lithium petroleum ether solution is added dropwise within half an hour, and after the reaction proceeds for half an hour, 25 ml of a solution of 27 g (0.25 mol) of trimethyl borate in tetrahydrofuran is further added dropwise at 78 C. within half an hour to obtain a transparent solution, the cryostat is removed, when the temperature rises spontaneously to 20 C. (for 2 hours), the solution is poured into 750 ml of deionized water having 100 ml of hydrochloric acid for hydrolysis and subjected to liquid separation, the aqueous phase is extracted once with 500 ml of ethyl acetate, and the organic layer is combined and washed to neutral. The solvent is evaporated off under a reduced pressure, 150 ml of petroleum ether is added, and after heating to boiling, cooling and filtration, 45 g of a white solid (1-a) with a yield of 83% is obtained.

[0048] Step 2

##STR00024##

[0049] 45 g (0.17 mol) of (1-a) and 300 ml of tetrahydrofuran are added to a 1 L three-necked flask and stirred to completely dissolved, and 60 g of hydrogen peroxide is added, stirred uniformly and heated to reflux for 7 h; and the reaction is stopped, the solution is cooled to room temperature, 300 ml of dichloromethane is added, oscillation is carried out for liquid separation, the aqueous layer is extracted with 300 ml2 of dichloromethane, and the dichloromethane is combined and washed with 300 ml2 of an aqueous saturated sodium chloride solution, followed by drying with 25 g of anhydrous sodium sulfate and solution rotary drying, to obtain 35 g of a light yellow liquid with a GC of 94.2% and a yield of 88%.

[0050] Step 3

##STR00025##

[0051] 33 g (0.14 mol) of (1-b), 22.6 (0.14 mol) of 2,3-difluorobenzene boric acid, 43 g (0.31 mol) of potassium carbonate, 300 ml of toluene and 100 ml of pure water are added to a 1 L three-necked flask and stirred to completely dissolved, 0.05 g of Pd-132 is added under the protection of nitrogen, followed by heating and a reflux reaction for 5 h; and the reaction is stopped, 300 ml of pure water is added and stirred for liquid separation, the aqueous layer is extracted with 200 ml2 of toluene, the organic layer is combined and washed with 300 ml2 of saturated salt solution, followed by the rotary drying of the solvent under a reduced pressure, 100 g of petroleum ether is added to the resulting liquid and stirred uniformly, and recrystallization is carried out at 20 C. to obtain 30 g of a white solid (1-c) with a GC of 99.0% and a yield of 81%.

[0052] Step 4

##STR00026##

[0053] 30 g (0.11 mol) of (1-c) is added to a 500 ml three-necked flask, 200 ml of dimethylsulfoxide (DMSO) is added under the protection of nitrogen and stirred uniformly, and 8.8 g (0.22 mol) of 60% sodium hydride mineral oil is added, heated to 120 C. and stirred for 4 hours; and the reaction is stopped, the reaction liquid is cooled to room temperature, poured to 300 g of ice water and stirred, a large amount of solid is precipitated, the solid is subjected to suction filtration with a filter cloth and aired to obtain a solid, 200 ml of petroleum ether is added and heated to complete dissolution, followed by passing through a 30 g hot silica gel column, the column is rinsed with 200 ml of hot petroleum ether, and after the rotary drying of the solution, 1 fold of toluene and 2 folds of petroleum ether are added and heated to complete dissolution, followed by recrystallization at 0 C. twice, to obtain 12 g of a white solid (I1-1) with a GC of 99.90% and a yield of 42%.

Example 2. Compound as Represented by Formula I5-1

[0054] ##STR00027##

[0055] Step 1

##STR00028##

is synthesized using 2-fluoro-4-bromocyclopropylbenzene as a raw material with reference to Step 1 in Example 1;

[0056] Step 2

##STR00029##

is synthesized using (2-a) as a raw material with reference to Step 2 in Example 1;

[0057] Step 3

##STR00030##

is synthesized using (2-b) and 2,3,4-trifluorobenzeneboronic acid as raw materials with reference to Step 3 in Example 1; and

[0058] Step 4

[0059] the target compound I5-1

##STR00031##

is synthesized using (2-c) as a raw material with reference to Step 4 in Example 1.

Example 3. Compound as Represented by Formula I9-1

[0060] ##STR00032##

[0061] Step 1

##STR00033##

is synthesized using 2-fluoro-4-bromobenzenecyclobutyl ether as a raw material with reference to Step 1 in Example 1;

[0062] Step 2

##STR00034##

is synthesized using (3-a) as a raw material with reference to Step 2 in Example 1;

[0063] Step 3

##STR00035##

is synthesized using (3-b) and 2,3-difluoro-4-pentylbenzeneboronic acid as raw materials with reference to Step 3 in Example 1; and

[0064] Step 4

[0065] the target compound I9-1

##STR00036##

is synthesized using (3-c) as a raw material with reference to Step 4 in Example 1.

Example 4. Compound as Represented by Formula I12-1

[0066] ##STR00037##

[0067] Step 1

##STR00038##

is synthesized using 2-fluoro-4-bromobenzenecyclopropyl methyl ether as a raw material with reference to Step 1 in Example 1;

[0068] Step 2

##STR00039##

is synthesized using (4-a) as a raw material with reference to Step 2 in Example 1;

[0069] Step 3

##STR00040##

is synthesized using (4-b) and 2,3-difluoro-4-butoxybenzeneboronic acid as raw materials with reference to Step 3 in Example 1; and

[0070] Step 4

[0071] the target compound I12-1

##STR00041##

is synthesized using (4-c) as a raw material with reference to Step 4 in Example 1.

Example 5. Compound as Represented by Formula I15-2

[0072] ##STR00042##

[0073] Step 1

##STR00043##

is synthesized using 2-(2-fluoro-4-bromophenethyl)tetrahydrofuran as a raw material with reference to Step 1 in Example 1;

[0074] Step 2

##STR00044##

is synthesized using (5-a) as a raw material with reference to Step 2 in Example 1;

[0075] Step 3

##STR00045##

is synthesized using (5-b) and 2,3-difluoro-4-butoxybenzeneboronic acid as raw materials with reference to Step 3 in Example 1; and

[0076] Step 4

[0077] the target compound I15-2

##STR00046##

is synthesized using (5-c) as a raw material with reference to Step 4 in Example 1.

Example 6. Compound as Represented by Formula I12-2

[0078] ##STR00047##

[0079] Step 1

##STR00048##

is synthesized using 2-fluoro-4-bromobenzenecyclopentyl methyl ether as a raw material with reference to Step 1 in Example 1;

[0080] Step 2

##STR00049##

is synthesized using (6-a) as a raw material with reference to Step 2 in Example 1;

[0081] Step 3

##STR00050##

is synthesized using (6-b) and 2,3-difluoro-4-butoxybenzeneboronic acid as raw materials with reference to Step 3 in Example 1; and

[0082] Step 4

[0083] the target compound I12-2

##STR00051##

is synthesized using (6-c) as a raw material with reference to Step 4 in Example 1.

Mixture Examples

[0084] In the following examples, the parts involved therein are all in weight percentage content, the temperature unit is C., and the specific meaning of the other symbols and the test conditions are as follows:

[0085] SN represents the melting point ( C.) of the liquid crystal from a crystal state to a nematic phase;

[0086] c.p. represents the clear point ( C.) of a liquid crystal, with the test instrument being Mettler-Toledo-FP System microthermal analyzer;

[0087] 1 is rotary viscosity (mPa.Math.s), with the test conditions being: 25 C., INSTEC: ALCT-IR1, and a 18 micron vertical box;

[0088] K.sub.11 is a twist elastic constant, and K.sub.33 is a splay elasticity constant, with the test conditions being: 25 C., INSTEC: ALCT-IR1 and a 18 micron vertical box;

[0089] represents dielectric anisotropy, =//.sub., wherein // is the dielectric constant parallel to the molecular axis, and .sub. is the dielectric constant perpendicular to the molecular axis, with the test conditions being: 25 C., INSTEC: ALCT-IR1 and an 18 micron vertical box;

[0090] n represents optical anisotropy, n=n.sub.on.sub.e, wherein n.sub.o is the refractive index of an ordinary light, n.sub.e is the refractive index of an extraordinary light, with the test conditions being: 589 nm, 250.2 C.;

[0091] In the following Examples 1 to 11, liquid crystal compounds of general formulas I, II, III and IV are weighed separately in a ratio to prepare liquid crystal media. All the various liquid crystal monomers used may be synthesized by known methods or be commercially available.

[0092] Devices and instruments used to prepare the liquid crystal media are:

[0093] (1) an electronic precision balance (with an accuracy of 0.1 mg)

[0094] (2) stainless steel beakers for liquid crystal weighing

[0095] (3) spoons for monomer addition

[0096] (4) a magnetic rotor for stirring

[0097] (5) a temperature-controlled electromagnetic stirrer

[0098] The method for preparing a liquid crystal medium comprises the following steps:

[0099] (1) monomers to be used are placed in order neatly;

[0100] (2) a stainless steel beaker is placed on the balance, and the monomers are placed into the stainless steel beaker with small spoons;

[0101] (3) monomer liquid crystals are added in sequence in weights as required;

[0102] (4) the stainless steel beaker with the materials having been added is placed on the magnetic stirrer, heated and melted; and

[0103] (5) after most of the mixture in the stainless steel beaker is melted, a magnetic rotor is added to the stainless steel beaker to stir the liquid crystal mixture uniformly, and the mixture is cooled to room temperature to obtain the liquid crystal medium.

[0104] The obtained liquid crystal medium is filled between two substrates of a liquid crystal display for performance test. The test results of the monomer structures of the specific compounds, the amounts (in weight percentage content), and the performance parameters of the resulting liquid crystal medium are listed in tables.

TABLE-US-00001 TABLE 1 The ratio of the components of the liquid crystal composition of Example 6 and the performance parameters thereof Compound Weight General percentage Performance formula Liquid crystal structure formula content (%) parameter V [00052] 3 S-N: 40 C. c.p: 90 C. .sub.1: 125 mPas n: 0.108 V [00053] 10 n.sub.e: 1.596 : 4.0 .sub.: 8.0 K.sub.11/K.sub.33: 14.5/15.7 V [00054] 10 After the composition is stored at 20 C. for 480 h, no V [00055] 10 crystallization occurs. IV [00056] 9 IV [00057] 9 IV [00058] 8 IV [00059] 4 IV [00060] 3 IV [00061] 5 IV [00062] 5 IV [00063] 6 IV [00064] 2 I [00065] 9 I [00066] 7

TABLE-US-00002 TABLE 2 The ratio of the components of the liquid crystal composition of Example 7 and the performance parameters thereof Compound Weight General percentage Performance formula Liquid crystal structure formula content (%) parameter V [00067] 38 S-N: 40 C. c.p: 98 C. .sub.1: 147 mPas n: 0.113 V [00068] 3 n.sub.e: 1.612 : 6.1 .sub.: 110 K.sub.11/K.sub.33: 14.7/16.3 IV [00069] 5 After the composition is stored at 20 C. for 480 h, no crystallization occurs. IV [00070] 8 Low temperature intersolubility indicator? IV [00071] 5 IV [00072] 5 IV [00073] 6 IV [00074] 6 I [00075] 8 I [00076] 16

TABLE-US-00003 TABLE 3 The ratio of the components of the liquid crystal composition of Example 8 and the performance parameters thereof Weight Compound percentage General content Performance formula Liquid crystal structure formula (%) parameter V [00077] 12 S-N: 40 C. c.p: 97 C. .sub.1: 174 mPas n: 0.144 V [00078] 10 n.sub.e: 1.632 : 5.0 .sub.: 8.5 K.sub.11/K.sub.33: 15.2/17.0 V [00079] 3 After the composition is stored at 20 C. for 480 h, no crystallization occurs. V [00080] 5 IV [00081] 3 IV [00082] 9 IV [00083] 6 IV [00084] 3 IV [00085] 5 IV [00086] 15 IV [00087] 13 I [00088] 6 I [00089] 10

TABLE-US-00004 TABLE 4 The ratio of the components of the liquid crystal composition of Example 9 and the performance parameters thereof Compound Weight General percentage Performance formula Liquid crystal structure formula content (%) parameter V [00090] 17 S-N: 40 C. c.p: 105 C. .sub.1: 175 mPas n: 0.130 V [00091] 12 n.sub.e: 1.575 : 4.6 .sub.: 8.6 K.sub.11/K.sub.33: 15.5/17.0 V [00092] 4 After the composition is stored at 20 C. for 480 h, no crystallization occurs. V [00093] 3 V [00094] 5 IV [00095] 5 IV [00096] 4 IV [00097] 4 IV [00098] 8 IV [00099] 8 IV [00100] 5 IV [00101] 12 IV [00102] 12 I [00103] 1

TABLE-US-00005 TABLE 5 The ratio of the components of the liquid crystal composition of Example 10 and the performance parameters thereof Compound Weight General percentage Performance formula Liquid crystal structure formula content (%) parameter V [00104] 14 S-N: 40 C. c.p: 106 C. .sub.1: 166 Pas n: 0.106 V [00105] 7 n.sub.e: 1.595 : 5.7 .sub.: 8.8 K.sub.11/K.sub.33: 14.2/16.0 V [00106] 3 After the composition is stored at 20 C. for 480 h, no crystallization occurs. V [00107] 8 V [00108] 7 V [00109] 7 IV [00110] 5 IV [00111] 5 IV [00112] 4 IV [00113] 5 IV [00114] 10 IV [00115] 10 IV [00116] 5 I [00117] 5

TABLE-US-00006 TABLE 6 The ratio of the components of the liquid crystal composition of Example 11 and the performance parameters thereof Compound Weight General percentage Performance formula Liquid crystal structure formula content (%) parameter V [00118] 32 S-N: 40 C. c.p: 95 C. .sub.1: 115 mPas n: 0.122 IV [00119] 12 n.sub.e: 1.603 : 5.5 .sub.: 9.0 K.sub.11/K.sub.3: 14.5/16.5 After the composition is IV [00120] 12 stored at 20 C. for 480 h, no crystallization occurs. IV [00121] 8 IV [00122] 8 IV [00123] 8 IV [00124] 8 I [00125] 5 I [00126] 7

TABLE-US-00007 TABLE 7 The ratio of the components of the liquid crystal composition of Example 12 and the performance parameters thereof Compound Weight General percentage Performance formula Liquid crystal structure formula content (%) parameter V [00127] 38 S-N: 40 C. c.p: 100 C. .sub.1: 148 mPas n: 0.115 V [00128] 3 n.sub.e: 1.617 : 6.0 .sub.: 11.0 K.sub.11/K.sub.33: 14.8/16.6 IV [00129] 5 After the composition is stored at 20 C. for 480 h, no crystallization occurs. IV [00130] 8 Is there any data under the conditions of 20 C.? IV [00131] 10 IV [00132] 10 IV [00133] 6 IV [00134] 6 I [00135] 9 I [00136] 5

TABLE-US-00008 TABLE 8 The ratio of the components of the liquid crystal composition of Example 13 and the performance parameters thereof Compound Weight General percentage Performance formula Liquid crystal structure formula content (%) parameter V [00137] 14 S-N: 20 C. c.p: 105 C. .sub.1: 123 Pas n: 0.105 V [00138] 7 n.sub.e: 1.594 : 5.4 .sub.: 8.5 K.sub.11/K.sub.33: 13.3/15.0 V [00139] 3 After the composition is stored at 20 C. for 240 h, no V [00140] 8 crystallization occurs. V [00141] 7 V [00142] 7 IV [00143] 5 IV [00144] 5 IV [00145] 4 IV [00146] 5 IV [00147] 10 IV [00148] 10 IV [00149] 5 I [00150] 5

[0105] As can be seen from the performance parameters of the liquid crystal compositions shown in Examples 6-12, the liquid crystal compositions of the present invention have a very good intersolubility and a very great negative dielectric constant; moreover, as can be seen upon the comparison between Example 10 and Example 13, the dibenzofuran-based liquid crystal compound having the cycloalkyl as the terminal group, compared with the dibenzofuran-based liquid crystal having the traditional flexible alkyl chain as the terminal group, exhibits a better intersolubility, and thus the use of a compound as represented by formula i provided by the present invention can improve the intersolubility of a liquid crystal compound and extend the application range of a liquid crystal mixture, producing an important application value.

[0106] Although only the specific compounds of the above-mentioned 8 examples and the compounding amounts (weight percentage content) thereof are listed and subjected to a performance test in the present invention, the liquid crystal compositions of the present invention can be further expanded and modified on the basis of the above-mentioned examples using the liquid crystal compounds represented by general formulas I, IV and V and the preferred liquid crystal compounds of general formulas I, IV and V, and they can all achieve the object of the present invention by appropriately adjusting the ratio thereof.