COMPOUND AND LIQUID CRYSTAL COMPOSITION

Abstract

There is provided a ferroelectric liquid crystal (FLC) material for the deformed helix FLC (DHFLC) electro-optical mode devices and shows optimum electro-optical properties including high tilt angle (>38°), and short helix pitch (<120 nm), and spontaneous polarization (>100 nC/cm.sup.2) comprising at least two components, wherein at least one FLC component is a chiral compound of Formula (I):

##STR00001##

particularly:

##STR00002##

wherein W.sub.1 and W.sub.2 are chiral groups with polar substituent at chiral centre, A and B are independently N atom or CH groups providing that at least one of A or B is N atom. Other various groups are as defined herein.

Claims

1. A ferroelectric liquid crystal (FLC) material for the deformed helix FLC (DHFLC) electro-optical mode devices comprising at least two components and shows optimum electro-optical properties, wherein at least one FLC component is a chiral compound of Formula (I): ##STR00149## wherein: n is 0 or 1; R.sup.1, R.sup.2, R.sup.3 and R.sup.4 each independently are 1,4-phenylene, or pyrimidine-2,5-diyl, or pyridine-2,5-diyl, optionally substituted with one or more substituents selected from the group consisting of halogen and methyl, provided that both of the rings R.sup.1 and R.sup.4 are not unsubstituted 1,4-phenylene; A.sup.1 and A.sup.2 are independently absent, that has meaning the group W.sup.1 or W.sup.2 are directly attached to the rings R.sup.1 or R.sup.4, or selected from the group consisting of —O—, —S—, and ester; and W.sup.1 and W.sup.2 are independently chiral alkyl C.sub.mH.sub.2m+1 or alkenyl C.sub.mH.sub.2m, wherein m=4-14, and optionally wherein one or more hydrogens are independently replaced by F, Cl or cyano, and optionally one or more CH.sub.2 are independently replaced with CF.sub.2, O, or —CO— groups provided that two O atoms are not linked together.

2. The FLC material of claim 1, wherein W.sup.1 and W.sup.2 are independently substituted at their chiral center/centers with at least one moiety selected from the group consisting of F, Cl, trifluoromethyl, O, and cyano.

3. The FLC material of claim 1, wherein W.sup.1 and W.sup.2 are independently selected from the group consisting of: ##STR00150## ##STR00151## wherein X is fluoro or chloro or cyano; and p is an integer in the range of 2 to 10.

4. The FLC material of claim 1, wherein the chiral compound of Formula (I) is of Formula (Ia): ##STR00152## wherein R.sup.3, W.sup.1 and W.sup.2 are as defined in claim 1.

5. The FLC material of claim 1, wherein the chiral compound of Formula (I) is of Formula (Ib): ##STR00153## wherein R.sup.3, W.sup.1 and W.sup.2 are as defined in claim 1.

6. The FLC material of claim 1, wherein the chiral compound of Formula (I) is of Formula (Ic): ##STR00154## wherein R.sup.3, W.sup.1 and W.sup.2 are as defined in claim 1.

7. The FLC material of claim 1, wherein the chiral compound of Formula (I) is of Formula (Id): ##STR00155## wherein R.sup.3, W.sup.1 and W.sup.2 are as defined in claim 1.

8. The FLC material of claim 1, wherein the chiral compound of Formula (I) is of Formula (Ie): ##STR00156## wherein R.sup.3, W.sup.1 and W.sup.2 are as defined in claim 1.

9. The FLC material of claim 1, wherein the chiral compound of Formula (I) is of Formula (If): ##STR00157## wherein R.sup.3, W.sup.1 and W.sup.2 are as defined in claim 1.

10. FLC material of claim 1, wherein the chiral compound of Formula (I) is selected from the group consisting of: ##STR00158##

11. The FLC material of claim 1, further comprising at least one achiral smectic C liquid crystal compound of Formula (II): ##STR00159## wherein: R.sup.5, R.sup.6, R.sup.7, and R.sup.8 independently are 1,4-phenylene, or pyrimidine-2,5-diyl, or pyridine-2,5-diyl, optionally substituted with at least one substituent selected from the group consisting of halogen and methyl; k is 0 or 1; A.sup.3 and A.sup.4 are independently absent or selected from the group consisting of —O—, —S—, and ester; and W.sup.3 and W.sup.4 are independently alkyl C.sub.mH.sub.2m+1 or alkenyl C.sub.mH.sub.2m, wherein m=4-12, and optionally one or more hydrogens are independently replaced by F, furthermore, optionally one or more CH.sub.2 are independently replaced with CF.sub.2, O, or —CO— groups provided that two O atoms are not linked together.

12. The FLC material of claim 11, wherein the achiral smectic C liquid crystal compound of Formula (II) is of the Formula (IIa): ##STR00160## wherein R.sup.11 and R.sup.12 independently are 1,4-phenylene, or pyrimidine-2,5-diyl, or pyridine-2,5-diyl, optionally substituted with at least one substituent selected from the group consisting of halogen and methyl; and W.sup.3, A.sup.4 and W.sup.4 are as defined in claim 11.

13. The FLC material of claim 11, wherein the achiral smectic C liquid crystal compound of Formula (II) is selected from the group consisting of: ##STR00161##

14. The FLC material of claim 11, wherein an average length of W.sup.1 and W.sup.2 is larger than an average length of W.sup.3 and W.sup.4.

15. The FLC material of claim 11, wherein an average length of W.sup.1 and W.sup.2 is equal to an average length of W.sup.3 and W.sup.4 or larger than that by up to 2-times.

16. The FLC material of claim 11, wherein the total number of rings in R.sup.1, R.sup.2, R.sup.3 and R.sup.4 is equal to the total numbers of rings in R.sup.5, R.sup.6, R.sup.7 and R.sup.8.

17. The FLC material of claim 11, wherein the chiral compound of Formula (I) and the achiral smectic C liquid crystal compound of Formula (II) have a molar ratio in the range of 10:90 to 40:60.

18. The FLC material of claim 11, wherein the chiral compound of Formula (I) has a concentration of less than 20 molar % based on the total number of moles of the FLC material, and wherein the FLC material has a spontaneous polarization of larger than 50 nC/cm.sup.2 at standard ambient temperature and pressure.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0130] The accompanying drawings illustrate a disclosed embodiment and serves to explain the principles of the disclosed embodiment. It is to be understood, however, that the drawings are designed for purposes of illustration only, and not as a definition of the limits of the invention.

[0131] FIG. 1 shows temperature dependence of tilt angle for the mixture FLC-4-1. The vertical dotted line denoted the temperature of the phase transition SmC*.fwdarw.SmA in absence of external electric field.

[0132] FIG. 2 shows temperature dependence of spontaneous polarization for the mixture FLC-4-1. The vertical dotted line denoted the temperature of the phase transition SmC*.fwdarw.SmA in absence of external electric field.

[0133] FIG. 3 shows temperature dependence of the helix pitch for the mixture FLC-4-1. The vertical bold line denoted the temperature of the phase transition SmC*.fwdarw.SmA in absence of external electric field.

[0134] FIG. 4 shows dependence of response time, τ.sub.ON at 90 Hz, FLC-4-1, at 25° C., cell gap 1.6 μm.

[0135] FIG. 5 shows (a) temperature dependence of tilt angle for the mixture FLC-4-7, where the vertical dotted line denotes the temperature of the phase transition SmC*.fwdarw.SmA in absence of external electric field, (b) temperature dependence of spontaneous polarization for the mixture FLC-4-7, where the vertical dotted line denotes the temperature of the phase transition SmC*.fwdarw.SmA in absence of external electric field, (c) temperature dependence of the helix pitch (p0) for the mixture FLC-4-7, where the vertical dotted line denotes the temperature of the phase transition SmC*.fwdarw.SmA in absence of external electric field.

[0136] FIG. 6 shows dependence of response time, τ.sub.ON at 90 Hz, for mixture FLC-4-7 at 25° C., cell gap 1.6 μm.

[0137] FIG. 7 shows temperature dependence of tilt angle for the mixture FLC-6-1. The vertical dotted line denoted the temperature of the phase transition SmC*.fwdarw.SmA in absence of external electric field.

[0138] FIG. 8 shows dependence of response time, τ.sub.ON at 90 Hz, for mixture FLC-6-1 at 25° C., cell gap 1.6 μm.

EXAMPLES

[0139] General

[0140] Non-limiting examples of the invention and comparative examples will be further described in greater detail by reference to specific Examples, which should not be construed as in any way limiting the scope of the invention.

[0141] All chemicals are commercially available from Merck, Meryer, Dieckmann HK, Fluorochem or TCI and used as received unless otherwise specified. Biphenylpyrimidines were supplied by TitanSci, China. Silica gel used for flash chromatography was Silica gel 60 (0.040-0.060 mm). Thin Layer chromatography (TLC) was performed on TLC plates, Merck, UV254, using an appropriate solvent as an eluent.

[0142] The following abbreviation for the common chemicals were used:

TABLE-US-00007 DCC—dicyclohexylcarbodiimide DCM—dichloromethane DMAP—4-N,N-dimethylaminopyridine DMF—N,N-dimethylformamide dppf—bis(diphenylphosphino)ferrocene SDS—sodium dodecylsulphate TolH—toluene

[0143] Synthesis of chiral 2-trifluoromethylalkanols with ee>97% were carried out as described by V. Mikhailenko, D. Yedamenko, G. Vlasenko, A. Krivoshey, V. Vashchenko//Tetrahedron Lett.-2015.-Vol. 56, Is. 43.-P. 5956-5959.

[0144] Chiral components with unsubstituted central terphenyl ring (S-FODTA-n) that was used as comparative compounds:

##STR00039##

were synthesized as described in Mikhailenko et. Al., J. Mol. Liq. 281 (2019) 186-195.

[0145] Two-ring phenylpyrimidines were synthesized as described by Kenji Shinjo, Takao Takiguchi, Hiroyuki Kitayama, Kazuharu Katagiri, Masahiro Terada, Takeshi Togano, Masataka Yamashita, Takashi Iwaki, Shosei Mori, Chiral smectic liquid crystal composition and liquid crystal device using same, EP0347941A2, priority 1988 Jun. 24 and by Terashima, Kanetsugu; Ichihashi, Mitsuyoshi; Takeshita, Fusayuki; Kikuchi, Makoto; Furukawa, Kenji EP 293.763 (1988/12/07).

[0146] Difluoroterphenyls were synthesized as described by G. W. Gray, M. Hird, D. Lacey, K. J. Toyne, Journal of the Chemical Society, Perkin Transactions 2 (1989) 2041-2053.

[0147] Degassing of solution were carried out by its sequential 3 cycles of pumping out to ˜100 mbar and filling with N.sub.2.

[0148] Mixtures of compounds were prepared by thoroughly stirring the appropriate amounts of components using a shaker or magnetic stirrer at temperature 110-120° C. under nitrogen atmosphere for at least 10 min.

[0149] Phase transition of the LC mixtures were determined by differential scanning calorimetry using ThermoScientific DSC-25 instrument. Assignment of the LC phase were carried out by polarizing microscopy using Olympus BX-60 microscope equipped with custom made hot stage.

[0150] Helix pitch in the absence of external voltage (p.sub.0) were measured by selective reflection of the light at both normal and oblique incidence of the light as it was described in prior art Mikhailenko et. Al., J. Mol. Liq. 281 (2019) 186-195. The cell of 15-25 μm coated onto inner side with chromolane as a vertically aligning material were used.

[0151] FLC properties for the mixtures were measured in ITO coated glass cell of 1.6-1.7 μm thickness; inner side of the cell were coated with 30 nm layer of Nylon-6 rubbed unidirectionally. The cell was mounted in a custom-made hot stage, providing temperature control ±0.1° C.

[0152] The spontaneous polarization (P.sub.S) was measured by the flipping current across a cascaded 560 kOhm resistance. The flipping current across the resistor is measured by the oscilloscope.

[0153] Tilt angle was measured by rotating the cell while a square wave with Vpp 10V/um is applied on the cell. Tilt angle is half of the rotation angle when the output intensity drops to zero for positive or negative polarity of the signal.

[0154] Response time is time required to change the optical transmittance from 10% to 90%.

[0155] Critical voltage of helix unwinding was determined as the critical voltage when the response time reaches the maximum value.

[0156] The examples 1-16 disclose the methods of synthesis of compounds according to the claims that are used as chiral components.

Example 1

[0157] Synthesis of bis-(S-1-trifluoromethylheptyl) 2,2″-difluoro-[1,1′:4′,1″-ter-phenyl]-4,4″-dicarboxylate (1b) was carried out in two steps accordingly to the scheme below:

##STR00040##

S-1-(trifluoromethyl)heptyl-2-fluoro-4-bromobenzoate (1a)

[0158] A solution of 3.27 g (15.8 mmol) of DCC in 20 ml of dry DCM was added dropwise to a stirred and cooled (ice-water) mixture of 2.89 g (13.2 mmol) of 2-fluoro-4-bromobenzoic acid, 2.28 g (12.4 mmol) of S-2-(trifluoromethyl)-heptanol and 5 mg of DMAP in 30 ml of DCM. The mixture was then stirred until reaction was completed, which was monitored by TLC, then filtered through the short plug of silica gel. The silica gel was washed additionally with 150 ml of DCM. The combined solutions in DCM was evaporated to dryness furnishing product 1a, 5.2 g of oil, which solidified upon storage and used in the next step without additional purification.

Bis-(S-1-trifluoromethylheptyl) 2,2″-difluoro-[1,1′:4′,1″-terphenyl]-4,4″-dicarboxylate (1b)

[0159] A mixture of 2.22 g (5.8 mmol) of 1a, 0.40 g (2.4 mmol) of 1,4-phenylenediboronic acid, 0.30 g of SDS, 0.171 g of PdCl.sub.2dppf, 5 ml of 1-butanol, 10 ml of water, and 30 ml of toluene was degassed, then heated to reflux and added dropwise a degassed solution of 2.90 g (34.8 mmol) of NaHCO.sub.3 in 20 ml of water. The reaction mixture was refluxed additionally for 2 hours, then cooled down to ambient temperature and the organic layer was separated. The remaining aqueous layer was then extracted three times with toluene. The combined organic layers were then washed with water, dried over Na.sub.2SO.sub.4, purified by flash chromatography with toluene on short plug of silica gel and the resulting fractions containing the desired product in toluene was evaporated to dryness. The residual was purified by column chromatography on silica gel [50×2 cm, eluent TolH:Hexane (1:1 w/w)], and yielded 1.00 g (62%) of the product (1b) as a colorless oil.

Example 2

Synthesis of bis-(S-1-trifluoromethyloctyl) 2,2″-difluoro-[1,1′:4′,1″-terphenyl]-4,4″-di-carboxylate

[0160] ##STR00041##

[0161] Following the protocol described in Example 1, bis(S-1-trifluoromethyloctyl) 2,2″-difluoro-[1,1′:4′,1″-terphenyl]-4,4″-dicarboxylate was synthesized using the starting materials 2-fluoro-4-bromobenzoic acid 2.19 g (10 mmol); S-1-(trifluoromethyl)octanol 1.70 g (10 mmol); 1,4-phenylenediboronic acid 0.59 g (3.50 mmol) to yield 1 g (40%) of the desired product as a colorless oil.

Example 3

Synthesis of bis-(S-1-trifluoromethylhexyl) 2,2″-difluoro-[1,1′:4′,1″-terphenyl]-4,4″-dicarboxylate

[0162] ##STR00042##

[0163] Following the protocol described in Example 1, bis-(S-1-trifluoromethylhexyl) 2,2″-difluoro-[1,1′:4′,1″-terphenyl]-4,4″-dicarboxylate was synthesized using the starting materials 2-fluoro-4-bromobenzoic acid 2.19 g (10 mmol); S-1-(trifluoromethyl)hexanol 1.70 g (10 mmol); 1,4-phenylenediboronic acid 0.60 g (3.62 mmol) to yield 1.10 g (46%) of the desired product as a colorless oil.

Example 4

Synthesis of bis-(S-1-trifluoromethylheptyl) 3,3″-difluoro-[1,1′:4′,1″-terphenyl]-4,4″-dicarboxylate

[0164] ##STR00043##

[0165] Following the protocol described in Example 1, bis(S-1-(trifluoromethyl)heptyl) 3,3″-difluoro-[1,1′:4′,1″-terphenyl]-4,4″-dicarboxylate was synthesized using the starting materials 3-fluoro-4-bromobenzoic acid 1.78 g (8.1 mmol); S-1-(trifluoromethyl)heptanol 1.51 g (8.2 mmol); 1,4-phenylenediboronic acid 0.60 g (3.62 mmol) to yield 1.21 g (49%) of the desired product as colorless oil.

Example 5

Synthesis of bis-(S-1-trifluoromethylheptyl) 2,3,2″,3″-tetrafluoro-[1,1′:4′,1″-terphenyl]-4,4″-dicarboxylate

[0166] ##STR00044##

[0167] Following the protocol described in Example 1, bis-(S-1-trifluoromethylheptyl) 2,3,2″,3″-tetrafluoro-[1,1′:4′,1″-terphenyl]-4,4″-dicarboxylate was synthesized using the starting materials 2,3-difluoro-4-bromobenzoic acid 1.45 g (6.1 mmol); S-1-(trifluoromethyl)heptanol 1.130 g (6.1 mmol); 1,4-phenylenediboronic acid 0.50 g (3.02 mmol) to yield 1.20 g (55%) of the desired product with a melting point 63° C.

Example 6

Synthesis of bis(S-1-trifluoromethyl-heptyl) 6,6′-(1,4-phenylene)dipicolinate

[0168] ##STR00045##

[0169] Following the protocol described in Example 1, bis((S)-1-trifluoromethyl-heptyl) 6,6′-(1,4-phenylene)dipicolinate was synthesized using the starting materials 6-bromo-nicotinic acid 2.024 g (10 mmol); S-1-(trifluoromethyl)heptanol 1.760 g (9.54 mmol); 1,4-phenylenediboronic acid 0.624 g (3.76 mmol) to yield 1.00 g (41%) of the desired product having a melting point of 57° C.

Example 7

Synthesis of bis(S-1-trifluoromethylheptyl) 5,5′-(1,4-phenylene)dipicolinate

[0170] ##STR00046##

[0171] Following the protocol described in Example 1, bis((S)-1-trifluoromethylheptyl) 5,5′-(1,4-phenylene)dipicolinate was synthesized using the starting materials 5-bromopicolinic acid 1.94 g (9.6 mmol); S-1-(trifluoromethyl)heptanol 1.79 g (9.7 mmol); 1,4-phenylene-diboronic acid 0.58 g (3.5 mmol) to yield 0.85 g (37%) of the desired product having a melting point of 49° C.

Example 8

Synthesis of bis(S-1-trifluoromethylheptyl) 2,2′-(1,4-phenylene)bis(pyrimidine-5-carboxylate)

[0172] ##STR00047##

Following the protocol described in Example 1, bis(S-1-trifluoromethylheptyl)-2,2′-(1,4-phenylene)bis(pyrimidine-5-carboxylate) was synthesized using the starting materials 2-bromopyrimidine-5-carboxylic acid 2.03 g (10 mmol); S-1-(trifluoromethyl)heptanol 1.86 g (10.1 mmol); 1,4-phenylenediboronic acid 0.58 g (3.5 mmol) to yield 1.02 g (45%) of the desired product having a melting point of 62° C.

Example 9

Synthesis of bis-(S-1-trifluoromethylheptyl) 5,5′-(1,4-phenylene)bis(pyrimidine-2-carboxylate)

[0173] ##STR00048##

[0174] Following the protocol described in Example 1, bis((S)-1-(trifluoromethyl)heptyl) 5,5′-(1,4-phenylene)-bis(pyrimidine-2-carboxylate) was synthesized using the starting materials 5-bromopyrimidine-2-carboxylic acid 1.55 g (7.6 mmol); S-1-(trifluoromethyl)-heptanol 1.50 g (8.1 mmol); 1,4-phenylenediboronic acid 0.43 g (2.6 mmol) to yield 0.85 g (50%) of the desired product having a melting point of 70° C.

Example 10

Synthesis of bis((S)-octan-2-yl) 3,3″-difluoro-[1,1′:4′,1″-terphenyl]-4,4″-dicarboxylate

[0175] ##STR00049##

[0176] Following the protocol described in Example 1, bis((S)-octan-2-yl) 3,3″-difluoro-[1,1′:4′,1″-terphenyl]-4,4″-dicarboxylate was synthesized using the starting materials 2-fluoro-4-bromobenzoic acid 2.19 g (10 mmol); S-2-methylheptanol 1.30 g (10 mmol); 1,4-phenylenediboronic acid 0.50 g (3 mmol) to yield 0.902 g (52%) of the desired product as colorless oil.

Example 11

[0177] Synthesis of 4-((S)-1-ethoxy-1-oxopropan-2-yl) 4″-((S)-1,1,1-trifluorooctan-2-yl) [1,1′:4′,1″-terphenyl]-4,4″-dicarboxylate (11c) was carried out in three steps accordingly to the scheme below:

##STR00050## ##STR00051##

Synthesis of (S)-1-ethoxy-1-oxopropan-2-yl 4′-bromo-[1,1′-biphenyl]-4-carboxylate (11a)

[0178] To the suspension of 4′-bromo-[1,1′-biphenyl]-4-carboxylic acid (3.6 g, 13 mmol), (S)-(−)-ethyl lactate (1.69 g, 14.3 mmol) and DMAP (1.9 g, 15.6 mmol) in dry DCM (100 ml) a solution of DCC (3.2 g, 15.6 mmol) in 60 ml of dry DCM was added dropwise at 5° C. with stirring. The mixture was warmed to ambient temperature and stirred for 18 hours. Then it was filtered through a short pad of Celite, filtrate was washed sequentially by diluted HCl, saturated sodium carbonate and brine, then organic layer evaporated to dryness. The residue after evaporation was purified by flash chromatography on silica gel with mixture toluene and hexane (1/1) yielding 4.6 g of 11a (94%) as a yellowish oil.

Synthesis of (S)-1-ethoxy-1-oxopropan-2-yl 4′-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-[1,1′-biphenyl]-4-carboxylate (11b)

[0179] The degassed mixture of 2 g (5.32 mmol) of 11a, 2 g (7.78 mmol) of bis-(pinacolato)-diboron, 2.34 g of anhydrous potassium acetate, 0.08 g of PdCl.sub.2dppf (0.106 mmol) in 25 ml of dioxane was stirred at 85° C. for 16 hours. After cooling down to ambient temperature product was extracted with ethyl acetate (3×20 ml). The combined organic layers were then washed with water and evaporated to dryness. Residue was purified by flash chromatography silica gel, eluent Toluene:Hexane (1:1 v/v). Fractions containing the desired product was evaporated to dryness furnishing 2.1 g of 11b (93%) as yellowish oil.

Synthesis of 4-((S)-1-ethoxy-1-oxopropan-2-yl) 4″-((S)-1,1,1-trifluorooctan-2-yl) [1,1′:4′,1″-terphenyl]-4,4″-dicarboxylate (tic)

[0180] A mixture of 1 g (2.36 mmol) of 11b, 0.739 g (2.36 mmol) of 1a (see Example 1), 0.052 g, (0.071 mmol) of PdCl.sub.2dppf, and SDS (0.3 mg) in a mixture of toluene (30 ml), n-butanol (5 ml), and H.sub.2O (20 ml) was degassed in vacuo and flushed with nitrogen for five times followed by heating to reflux with stirring. To the refluxed mixture a solution of Na.sub.2CO.sub.3—H.sub.2O (0.880 g, 6.08 mmol) in 10 ml of water degassed by nitrogen bubbling was added. The resulted mixture was stirred at reflux for 3 hours and cooled. The organic layer was separated and the water one was extracted with toluene (3×20 ml). The organic extracts were collected, washed with water and evaporated to dryness. The residue was purified by flesh chromatography on silica gel with mixture toluene and hexane (1/1) and recrystallized successively from hexane and acetonitrile. Yield 0.36 g (28%).

Example 12

Synthesis of 4″-((S)-1-ethoxy-1-oxopropan-2-yl) 4-((S)-1,1,1-trifluorooctan-2-yl) 3-fluoro-[1,1′:4′, 1″-terphenyl]-4,4″-dicarboxylate

[0181] ##STR00052##

[0182] Following the protocol described in Example 11, 4″-((S)-1-ethoxy-1-oxopropan-2-yl) 4-((S)-1,1,1-trifluorooctan-2-yl) 3-fluoro-[1,1′:4′,1″-terphenyl]-4,4″-dicarboxylate was synthesized using as the starting materials (S)-1,1,1-trifluorooctan-2-yl 4-bromo-2-fluorobenzoate (0.905 g, 2.36 mmol); the yield was 0.32 g (23%) of the desired product as colorless solid.

Example 13

[0183] Synthesis of Bis((S)-1,1,1-trifluorooctan-2-yl) [2,2′-binaphthalene]-6,6′-dicarboxylate (13c) was carried out in three steps accordingly to the scheme below:

##STR00053##

Synthesis of (S)-1,1,1-trifluorooctan-2-yl 6-bromo-2-naphthoate (13a)

[0184] To a suspension of 6-bromo-2-naphthoic acid (2.98 g, 11.9 mmol), (S)-1,1,1-trifluorooctan-2-ol (2.29 g, 12.4 mmol) and DMAP (160 mg, 1.3 mmol) in dry dichloromethane (90 ml) a solution of DCC (2.95 g, 14.3 mmol) in dry dichloromethane (40 ml) was added drop wise at 0-5° C. with stirring. The mixture was left to warm to room temperature overnight with stirring. Then it was filtered through a short pad of Celite and evaporated to dryness. The residue after evaporation was purified by flash chromatography with hot heptane giving after evaporation 13a as a clear solid. Yield 1.5 g (32%).

Synthesis of 1,1,1-Trifluorooctan-2-yl 6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2-naphthoate (13b)

[0185] The mixture of 0.70 g (1.68 mmol) of (S)-1,1,1-trifluorooctan-2-yl 6-bromo-2-naphthoate, 0.64 g (2.52 mmol) of bis(pinacolato)diboron, 0.495 g of anhydrous KOAc, 0.025 g of PdCl.sub.2dppf (0.0336 mmol) in 15 ml of dioxane was degassed and filled with N.sub.2, then heated at 85° C. for 16 hours. After cooling down to ambient temperature, product was extracted with ethyl acetate (3×20 ml). The combined organic layers were then washed with water and evaporated to dryness. Residue was purified by flash chromatography on silica gel, eluent Toluene:Hexane (1:1 v/v). Fractions containing the desired product was evaporated to dryness, yielding 0.5 g of 13b (67%) as colourless oil.

Synthesis of bis((S)-1,1,1-trifluorooctan-2-yl) [2,2′-binaphthalene]-6,6′-dicarboxylate (13c)

[0186] A degassed solution of 13b (0.5 g, 1.68 mmol), (S)-1,1,1-trifluorooctan-2-yl 6-bromo-2-naphthoate (0.7 g, 1.68 mmol), PdCl.sub.2dppf (0.037 g, 0.05 mmol), and SDS (0.2 mg) in a mixture of toluene (20 ml), n-butanol (5 ml), and H.sub.2O (10 ml) was heated to reflux with stirring. Then, a degassed solution of Na.sub.2CO.sub.3—H.sub.2O (0.83 g, 6.72 mmol) in 10 ml of water was added. The resulted mixture was refluxed for 3 hours and cooled to ambient temperature. The organic layer was separated and the water layer was extracted with toluene (3×20 ml). The organic extracts were collected, washed with water and evaporated to dryness. The residue was purified by flash chromatography on silica gel with mixture toluene and hexane (1/1). Yield is 0.48 g (46%) as colourless oil.

Example 14

[0187] Synthesis of bis((S)-1,1,1-trifluorooctan-2-yl) 6,6′-(1,4-phenylene)bis(2-naphthoate) (14) was carried out in two steps accordingly to the scheme below:

##STR00054##

[0188] A solution of 0.7 g, (1.68 mmol) of compound 13a (see Example 13), 1,4-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) benzene (0.253 g, 0.76 mmol), PdCl.sub.2dppf (0.035 g, 0.046 mmol), and SDS (0.2 mg) in a mixture of toluene (20 ml), n-butanol (5 ml), and H.sub.2O (10 ml) was degassed in vacuo and flashed with nitrogen for three times followed by heating to reflux with stirring. Then, a degassed solution of Na.sub.2CO.sub.3—H.sub.2O (0.754 g, 6.08 mmol) in 10 ml of water was added. The resulted mixture was stirred at reflux for 3 hours and cooled. The organic layer was separated and the water layer was extracted with toluene (3×20 ml). The organic extracts were collected, washed with water and evaporated to dryness. The residue was purified by flash chromatography on silica gel, eluent Toluene:Hexane (1:1 w/w) and recrystallized from acetonitrile. Yield 0.26 g (46%), melting point 135° C.

Example 15

[0189] ##STR00055##

[0190] Solution of 0.8 g (3.3 mmol) of 4,4′-biphenyl dicarboxylic acid (15a), 3 drops of DMF in mixture of 10 ml of SOCl.sub.2 and 20 ml of toluene for was refluxed for 6 h, then evaporated to dryness. The residual after evaporation was dissolved in 20 ml of dry dioxane, 1.24 g of (S)-1-(trifluoromethyl)heptanol was added, the solution was heated to 50° C. and 3.5 ml of pyridine was added dropwise under stirring. The mixture then was refluxed for 4 hours, evaporated to dryness and purified by flash chromatography on silica gel with mixture hexane-toluene 1:1 v/v. Yield of 15b was 1.18 g (62%) as colourless oil.

Example 16

[0191] Synthesis of 4,4″-bis((((S)-1-(trifluoromethyl)heptyl)oxy)methyl)-1,1′:4′,1″-terphenyl (16b) was carried out accordingly to the following scheme:

##STR00056##

[0192] Synthesis of (S)-1-bromo-4-(((1,1,1-trifluorooctan-2-yl)oxy)methyl)benzene (16a). To the mixture of 0.382 g (9.56 mmol) of NaH (60% suspension in oil) in 15 ml of dry DMF under in N.sub.2 atmosphere 1.17 g (6.37 mmol) of (S)-1-(trifluoromethyl)heptanol was added at 25° C. and stirred for 4 hours. Then, a solution of 1.75 g (7.01 mmol) of 1-bromo-4-(bromomethyl)benzene in 9 ml of dry DMF was added and stirred for 28 hours. Then mixture was diluted with cold 3% aqueous AcOH, extracted with DCM, washed with water, dried over Na.sub.2SO.sub.4. Drying agent was filtered off and solution in DCM was evaporated to dryness. The crude product was purified with flash chromatography on silica gel/hexane furnishing 2.106 g (94%) of 16a as a colourless oil used on the next step without additional purification.

[0193] Synthesis of 4,4″-bis((((S)-1-(trifluoromethyl)heptyl)oxy)methyl)-1,1′:4′,1″-terphenyl (16b) was carried out according to protocol described in Example 1 stage b. Quantities: 2.0 g (5.7 mmol) of (S)-1-bromo-4-(((1,1,1-trifluorooctan-2-yl)oxy)methyl)-benzene (16a); 0.425 g (2.57 mmol) of 1,4-phenylenediboronic acid; yield of desired product 16b was 0.516 g (32%) as a colourless solid.

[0194] Example 17-22 disclose the compositions of LC mixtures used as achiral hosts.

Example 17

[0195]

TABLE-US-00008 TABLE 1 Host mixture BPP-2 Components Content of the component, mol. % [00057] 73.7 [00058] 26.3

[0196] Mixture BPP-2 showed the following phase transitions:

##STR00059##

Example 18

[0197]

TABLE-US-00009 TABLE 2 Host mixture BPP-3. Components Content of the component, mol. % [00060] 50 [00061] 20 [00062] 30

[0198] Mixture BPP-3 showed the following phase transitions:

##STR00063##

Example 19

[0199]

TABLE-US-00010 TABLE 3 Host mixture BPP-4. Components Content of the component, mol. % [00064] 17.7 [00065] 40.1 [00066] 18.2 [00067] 24

[0200] Mixture BPP-4 showed the following phase transitions:

##STR00068##

Example 20

[0201]

TABLE-US-00011 TABLE 4 Host mixture BPP-6. Components Content of the component, mol. % [00069] 4.0 [00070] 5.0 [00071] 49.5 [00072] 19.8 [00073] 2.0 [00074] 19.8

[0202] Mixture BPP-6 showed the following phase transitions:

##STR00075##

Example 21

[0203]

TABLE-US-00012 TABLE 5 Host mixtures of the three laterally fluorinated dialkylterphenyls (DFT). Components Content of the component, mol. % [00076] 25 [00077] 50 [00078] 25

[0204] Mixture DFT showed the following phase transitions:

##STR00079##

Example 22

[0205]

TABLE-US-00013 TABLE 6 Host mixture PP-7. Content of the Components component, mol. % [00080] 37.5 [00081] 37.5 [00082] 25

[0206] Mixture PP-7 showed the following phase transitions:

##STR00083##

[0207] Resuming, the multicomponent mixtures of biphenylpyrimi dines (BPP-4 and BPP-6) and DFT mixture show wide enough range of desired SmC phase from ˜13-20 to 91-103° C., thus they are suitable as a achiral host. Whereas BPP-2 and BPP-3 have higher melting points, 28° C. and 36° C. respectively, which make them an appropriate medium only for express comparison of chiral components.

[0208] Example 23-Example 55 disclose the compositions of FLC mixtures of chiral components (compounds of type I) with achiral hosts and their properties.

Example 23

[0209]

TABLE-US-00014 TABLE 7 Composition of FLC-3-1 mixture. Components Content of the component, mol. % BPP-3 76.0 [00084] 24.0

TABLE-US-00015 TABLE 8 Properties of FLC-3-1 mixture (at 25° C.). Phase transitions [00085] Tilt angle, θ, degree 38 Spontaneous polarization, P.sub.S, nC/cm.sup.2 174 Switching time, τ.sub.ON, μs 380 Helix pitch, p.sub.0, nm 99 Critical voltage of helix unwinding, V.sub.C, V 4.6

[0210] The FLC-3-1 shows parameters that are close to optimal ones.

Example 24

[0211]

TABLE-US-00016 TABLE 9 Composition of FLC-3-2 mixture. Components Content of the component, mol. % BPP-3 85.6 [00086] 14.4

TABLE-US-00017 TABLE 10 The properties of FLC-3-2 mixture (at 25° C.). Phase transitions [00087] Tilt angle, θ, degree  36.5—below optimal value Spontaneous polarization, P.sub.S, nC/cm.sup.2  93.4—close to lowest margin Helix pitch, p.sub.0, nm 154—over the optimal value Critical voltage of helix unwinding, V.sub.C, V  5.0

[0212] The mixture FLC-3-2 shows lowest margin of Chiral component concentration.

Example 25

[0213]

TABLE-US-00018 TABLE 11 The composition of FLC-3-3 mixture. Components Content of the component, mol. % BPP-3 86.1 [00088] 23.9

TABLE-US-00019 TABLE 12 The properties of FLC-3-3 mixture (at 25° C.).   Phase transitions [00089] Helix pitch, p.sub.0, nm 145-over the optimal value Tilt angle, θ, degree  35-below optimal value Spontaneous polarization, P.sub.S, nC/cm.sup.2  92-below optimal value Switching time, τ.sub.ON, μs 80 Critical voltage of helix unwinding, V.sub.c, V  5.8

[0214] The effect of variation of linker type between central core and terminal chiral group.

[0215] The mixture shows not good alignment in the FLC cell.

Example 26

[0216]

TABLE-US-00020 TABLE 13 The composition of FLC-3-4 mixture. Content of the Components component, mol. % BPP-3 84.1 [00090] 15.9

TABLE-US-00021 TABLE 14 The properties of FLC-3-4 mixture (at 25° C.).   Phase transitions [00091] Helix pitch, p.sub.0, nm 218-over the optimal value Tilt angle, θ, degree 38.5 Spontaneous polarization, P.sub.S, nC/cm.sup.2 100-below optimal value Switching time, τ.sub.ON, μs 80 Critical voltage of helix unwinding, V.sub.c, V  5.8

[0217] The mixture shows the effect of variation of linker type between central core and terminal chiral group. Mixture shows not good alignment in the FLC cell.

Example 27

[0218]

TABLE-US-00022 TABLE 15 The composition of FLC-3-5 mixture. Content of the Components component, mol. % BPP-3 76 [00092] 24

TABLE-US-00023 TABLE 16 The properties of FLC-3-5 mixture (at 25° C.).   Phase transitions [00093] Tilt angle, θ, degree 36.5-below optimal value Spontaneous polarization, P.sub.S, nC/cm.sup.2 146 Switching time, τ.sub.ON, μs 390-slower than required value Helix pitch, p.sub.0, nm 112 Critical voltage of helix unwinding,  4.5 V.sub.c, V at 90 Hz

[0219] Comparative example showing results with known chiral component.

Example 28

[0220]

TABLE-US-00024 TABLE 17 The composition of FLC-4-1 mixture. Content of the Components component, mol. % BPP-4 85.0 [00094] 25.0

TABLE-US-00025 TABLE 18 The properties of FLC-4-1 mixture (at 25° C.).   Phase transitions [00095] Helix pitch, p.sub.0, nm (FIG. 3) 107 Tilt angle, θ, degree (FIG. 1)  40 Critical voltage of helix unwinding, V.sub.c, V at 90 Hz  8.8 Spontaneous polarization, P.sub.S, nC/cm.sup.2 (FIG. 2) 131.6 Response time, τ.sub.ON, μs (FIG. 4)  50

[0221] The FLC-4-1 shows parameters that are close to optimal values.

Example 29

[0222] FLC-4-2 Composition

TABLE-US-00026 TABLE 19 The composition of FLC-4-2 mixture. Content of the Components component, mol. % BPP-4 83.0 [00096] 17

TABLE-US-00027 TABLE 20 The properties of FLC-4-2 mixture (at 25° C.).   Phase transitions [00097] Helix pitch, p.sub.0, nm 133 Tilt angle, θ, degree  38.5 Critical voltage of helix unwinding, V.sub.c, V at 10 Hz  4 Spontaneous polarization, P.sub.S, nC/cm.sup.2  77.4 Switching on time, τ.sub.ON, μs  33

[0223] The mixture FLC-4-2 used for determination of lowest margin of chiral component concentration with acceptable set of properties.

Example 30

[0224]

TABLE-US-00028 TABLE 21 The composition of FLC-4-3 mixture. Content of the Components component, mol. % BPP-4 85.0 [00098] 25.0

TABLE-US-00029 TABLE 22 The properties of FLC-4-3 mixture (at 25° C.).   Phase transitions [00099] Helix pitch, p.sub.0, nm  95 Tilt angle, θ, degree  38 Critical voltage of helix unwinding, V.sub.c, V at 90 Hz  10.1 Spontaneous polarization, P.sub.S, nC/cm.sup.2 126 Switching on time, τ.sub.ON, μs  55

[0225] Examples shows effect of the length of terminal alkyl chain, c.f. with Example 28

Example 31

[0226]

TABLE-US-00030 TABLE 23 The composition of FLC-4-4 mixture. Content of the Components component, mol. % BPP-4 85.0 [00100] 25.1

TABLE-US-00031 TABLE 24 The properties of FLC-4-4 mixture (at 25° C.).   Phase transitions [00101] Helix pitch, p.sub.0, nm 119 Tilt angle, θ, degree  39.5 Critical voltage of helix unwinding, V.sub.c, V at 10 Hz  8.2 Spontaneous polarization, P.sub.S, nC/cm.sup.2 131 Switching on time, τ.sub.ON, μs  51

[0227] Examples shows effect of the length of terminal alkyl chain, c.f. with Example 28.

Example 32

[0228]

TABLE-US-00032 TABLE 25 The composition of FLC-4-5 mixture. Content of the Components component, mol. % BPP-4 84.8 [00102] 25.2

TABLE-US-00033 TABLE 26 The properties of FLC-4-5 mixture (at 25° C.).   Phase transitions [00103] Helix pitch, p.sub.0, nm 105 Tilt angle, θ, degree 36-below optimal value Critical voltage of helix unwinding, V.sub.c, V at 90 Hz  9.1 Spontaneous polarization, P.sub.S, nC/cm.sup.2 120 Switching on time, τ.sub.ON, μs  55

[0229] The example shows the effect of moving polar groups in the central core of the chiral component molecules towards their centre, c.f. with Example 28.

Example 33

[0230]

TABLE-US-00034 TABLE 27 The composition of FLC-4-6 mixture. Components Content of the component, mol. % BPP-4 85.1 [00104] 24.9

TABLE-US-00035 TABLE 28 The properties of FLC-4-6 mixture (at 25° C.). Phase transitions [00105] Helix pitch, p.sub.0, nm 97 Tilt angle, θ, degree 35—below optimal value Critical voltage of helix unwinding, V.sub.c, V at 90 Hz 9.9 Spontaneous polarization, P.sub.S, nC/cm.sup.2 152 Switching on time, τ.sub.ON, μs 64

[0231] The example shows the effect of moving polar groups in the central core of the chiral component molecules towards their centre on tilt angle, c.f. with Example 28.

Example 34

[0232]

TABLE-US-00036 TABLE 29 The composition of FLC-4-7 mixture. Components Content of the component, mol. % BPP-4 75.0 [00106] 25.0

TABLE-US-00037 TABLE 30 The properties of FLC-4-7 mixture (at 25° C.). Phase transitions [00107] Helix pitch, p.sub.0, nm (FIG. 5c)) 106.8 Tilt angle, θ, degree (FIG. 5(a)) 42.5 Critical voltage of helix unwinding, V.sub.c, V at 90 Hz 11.2 Spontaneous polarization, P.sub.S, nC/cm.sup.2 (FIG. 5(b)) 164 Response time at 8 V, τ.sub.ON, μs (FIG. 6) 90

Example 35

[0233]

TABLE-US-00038 TABLE 31 The composition of FLC-4-8 mixture. Components Content of the component, mol % BPP-4 75.0 [00108] 25.0

TABLE-US-00039 TABLE 32 The properties of FLC-4-8 mixture (at 25° C.). Phase transitions [00109] Helix pitch, p.sub.0, nm 95 Tilt angle, θ, degree 43 Critical voltage of helix unwinding, V.sub.c, V at 90 Hz 11.9 Spontaneous polarization, P.sub.S, nC/cm.sup.2 180 Switching on time at 10 V, τ.sub.ON, μs 80

Example 36

[0234]

TABLE-US-00040 TABLE 33 The composition of FLC-4-9 mixture. Components Content of the component, mol. % BPP-4 75.1 [00110] 24.9

TABLE-US-00041 TABLE 34 The properties of FLC-4-9 mixture (at 25° C.). Phase transitions [00111] Helix pitch, p.sub.0, nm 105 Tilt angle, θ, degree 41.5 Critical voltage of helix unwinding, V.sub.c, V at 90 Hz 10.5 Spontaneous polarization, P.sub.S, nC/cm.sup.2 144 Switching time at 10 V, τ.sub.ON, μs 78

Example 37

[0235]

TABLE-US-00042 TABLE 35 The composition of FLC-4-10 mixture. Components Content of the component, mol. % BPP-4 75.0 [00112] 25.0

TABLE-US-00043 TABLE 36 The properties of FLC-4-10 mixture (at 25° C.). Phase transitions [00113] Helix pitch, p.sub.0, nm 95 Tilt angle, θ, degree 43 Critical voltage of helix unwinding, V.sub.c, V at 90 Hz 11.5 Spontaneous polarization, P.sub.S, nC/cm.sup.2 180 Switching on time at 10 V, τ.sub.ON, μs 80

Example 38

[0236]

TABLE-US-00044 TABLE 37 The composition of FLC-4-11 mixture. Components Content of the component, mol. % BPP-4 75.0 [00114] 25.0

TABLE-US-00045 TABLE 38 The properties of FLC-4-11 mixture (at 25° C.). Phase transitions [00115] Helix pitch, p.sub.0, nm 165—over the optimal value Tilt angle, θ, degree 33.8—below optimal value Critical voltage of helix unwinding, V.sub.c, V at 90 Hz 5.8 Spontaneous polarization, P.sub.S, nC/cm.sup.2 54—below optimal value Switching on time at 10 V, τ.sub.ON, μs 78

[0237] The example shows an importance of highly polar group (like CF.sub.3, in FLC-4-1, see Example 28) at chiral centre: its changing with non-polar CH.sub.3 one reduces spontaneous polarization ˜2.4 times and HTP by ˜1.6 times (compare with Example 28)

Example 39. Comparative Example

[0238]

TABLE-US-00046 TABLE 39 The composition of FLC-4-12 mixture. Components Content of the component, mol. % BPP-4 82.9 [00116] 17.1

TABLE-US-00047 TABLE 40 The properties of FLC-4-12 mixture (at 25° C.). Phase transitions [00117] Helix pitch, p.sub.0, nm 136 Tilt angle, θ, degree 35.5—below optimal value Critical voltage of helix unwinding, V.sub.c, V, at 90 Hz 5.4 Spontaneous polarization, P.sub.S, nC/cm.sup.2 66.2—below optimal value Switching on time, τ.sub.ON, μs 50

[0239] Comparative example showing results with known chiral component. The example shows the effect of moving polar groups in the central core of the chiral component molecules towards their centre on tilt angle, c.f. with Example 29.

Example 40 Comparative Example

[0240]

TABLE-US-00048 TABLE 41 The composition of FLC-4-13 mixture. Components Content of the component, mol. % BPP-4 75 [00118] 25

TABLE-US-00049 TABLE 42 The properties of FLC-4-13 mixture (at 25° C.). Phase transitions [00119] Helix pitch, p.sub.0, nm 112 Tilt angle, θ, degree 36-below optimal value Critical voltage 7.3 of helix unwinding, V.sub.c, V at 10 Hz Spontaneous 96.2-close to lowest margin polarization, P.sub.S, nC/cm.sup.2 Switching on 80 time, τ.sub.ON, μs

[0241] Comparative example showing results with known chiral component. The example shows the effect of moving polar groups in the central core of the chiral component molecules towards their centre on tilt angle, c.f. with Example 28.

Example 41 Comparative Example

[0242]

TABLE-US-00050 TABLE 43 The composition of FLC-4-14 mixture. Content of the Components component, mol. % BPP-4 75.1 [00120] 24.9

TABLE-US-00051 TABLE 44 The properties of FLC-4-14 mixture (at 25° C.). Phase transitions [00121] Helix pitch, p.sub.0, nm 233-over the optimal value Tilt angle, θ, degree 30.5-below optimal value Critical voltage of helix unwinding, V.sub.c, V at 10 Hz 5.6 Spontaneous polarization, P.sub.S, nC/cm.sup.2 109.8-close to lowest margin Switching on time at 10 V, τ.sub.ON, μs 78

[0243] Comparative example showing results with known chiral component.

[0244] The example shows: [0245] an importance of highly polar group at chiral centre (like CF.sub.3, in FLC-4-1, see Example 28): its changing with non-polar CH.sub.3 reduces spontaneous polarization ˜1.2 times. [0246] Effect of polar group in the central core of the molecule on tilt angle, c.f. with Example 28

Example 42

[0247]

TABLE-US-00052 TABLE 45 The composition of FLC-4-15 mixture. Content of the Components component, mol. % BPP-4 75.2 [00122] 24.8

TABLE-US-00053 TABLE 46 The properties of FLC-4-15 mixture (at 25° C.). Phase transitions [00123] Helix pitch, p.sub.0, nm 240-over the optimal value Tilt angle, θ, degree 34.5-below optimal value Critical voltage of helix unwinding, V.sub.c, V, at 10 Hz 4.8 Spontaneous polarization, P.sub.S, nC/cm.sup.2 181 Switching on time at 10 V, τ.sub.ON, μs 52

[0248] Examples shows an effect of the type of terminal chiral units. Obviously, two different chiral units induce the same sign of P.sub.S (high value) and opposite sign of HTP (helix is unwounded to 240 nm), c.f. with Example 28.

Example 43

[0249]

TABLE-US-00054 TABLE 47 The composition of FLC-4-16 mixture. Content of the Components component, mol. % BPP-4 86 [00124] 14

TABLE-US-00055 TABLE 48 The properties of FLC-4-16 mixture (at 25° C.). Phase transitions [00125] Helix pitch, p.sub.0, nm 480-over the optimal value Tilt angle, θ, degree 32-below optimal value Spontaneous polarization, P.sub.S, nC/cm.sup.2 92-below optimal value

[0250] The example shows an effect of the nature and length of the central core in the chiral component, c.f. with Example 28. Due to high melting point, the chiral component is insufficiently soluble in the Host, even at 14 mol. % the melting point of the mixture increases to 29° C. Additionally, the tilt angle is too low, apparently due to notably longer molecule in the chiral component than in the Host.

Example 44

[0251]

TABLE-US-00056 TABLE 49 The composition of FLC-4-17 mixture. Content of the Components component, mol. % BPP-4 80 [00126] 20

TABLE-US-00057 TABLE 50 The properties of FLC-4-17 mixture (at 25° C.). Phase transitions [00127] Helix pitch, 348-over the optimal value p.sub.0, nm

[0252] The example shows an effect of the nature and length of the central core in the chiral component, c.f. with Example 28. As the molecules of Chiral components are shorter than that in the Host, the HTP is reduced and induced helix pitch is too large. The Chiral component is also not well compatible with the Host that resulted in reducing of T.sub.SmC* to 75° C.

Example 45

[0253]

TABLE-US-00058 TABLE 51 The composition of FLC-4-18 mixture. Content of the Components component, mol. % BPP-4 80 [00128] 20

TABLE-US-00059 TABLE 52 The properties of FLC-4-18 mixture (at 25° C.). Phase transitions [00129] Helix pitch, 650-over the optimal value p.sub.0, nm

[0254] The example shows an effect of the nature and length of the central core in the chiral component, c.f. with Example 28. Obviously, due to molecules of chiral components are shorter than that in the Host, the HTP is notably reduced and induced p.sub.0 is too large. The Chiral component is also poor compatible with the Host that resulted in reducing of T.sub.SmC* to 32°.

Example 46

[0255]

TABLE-US-00060 TABLE 53 The composition of FLC-6-1 mixture. Content of the Components component, mol. % BPP-6 74.9 [00130] 25.1

TABLE-US-00061 TABLE 54 The properties of FLC-6-1 mixture (at 25° C.). Phase transitions [00131] Helix pitch, p.sub.0, nm 91 Tilt angle, θ, degree (FIG. 7) 38.5 Critical voltage of helix unwinding, V.sub.c, V at 90 Hz 12 Spontaneous polarization, P.sub.S, nC/cm.sup.2 140 Switching on time, τ.sub.ON, μs (FIG. 8) 100

Example 47

[0256]

TABLE-US-00062 TABLE 55 The composition of FLC-6-2 mixture. Content of the Components component, mol. % BPP-6 75.0 [00132] 25.0

TABLE-US-00063 TABLE 56 The properties of FLC-6-2 mixture (at 25° C.). Phase transitions [00133] Helix pitch, p.sub.0, nm 112 Tilt angle, θ, degree 39.5 Critical voltage of helix unwinding, V.sub.c, V at 90 Hz 8.2 Spontaneous polarization, P.sub.S, nC/cm.sup.2 132 Switching on time, τ.sub.ON, μs 77

Example 48

[0257]

TABLE-US-00064 TABLE 57 The composition of FLC-6-3 mixture. Content of the Components component, mol. % BPP-6 75.0 [00134] 25.0

TABLE-US-00065 TABLE 58 The properties of FLC-6-3 mixture (at 25° C.). Phase transitions [00135] Helix pitch, p.sub.0, nm 91 Tilt angle, θ, degree 36 Critical voltage of helix unwinding, V.sub.c, V 11.0 Spontaneous polarization, P.sub.S, nC/cm.sup.2 141 Switching on time, τ.sub.ON, μs 85

[0258] The example shows effect of the length of terminal alkyl chain on helix pitch and on tilt angle, c.f. with Example 46

Example 49

[0259]

TABLE-US-00066 TABLE 59 The composition of FLC-6-4 mixture. Content of the Components component, mol. % BPP-6 83.2 [00136] 16.8

TABLE-US-00067 TABLE 60 The properties of FLC-6-4 mixture (at 25° C.). Phase transitions [00137] Helix pitch, p.sub.0, nm 123 Tilt angle, θ, degree 42.0 Critical voltage of helix unwinding, V.sub.c, V 7.5 Spontaneous polarization, P.sub.S, nC/cm.sup.2 94.5 Switching on time, τ.sub.ON, μs 54

Example 50 Comparative Example

[0260]

TABLE-US-00068 TABLE 61 The composition of FLC-6-5 mixture. Content of the Components component, mol. % BPP-6 74.9 [00138] 25.1

TABLE-US-00069 TABLE 62 The properties of FLC-6-5 mixture (at 25° C.). Phase transitions [00139] Helix pitch, p.sub.0, nm 125 Tilt angle, θ, degree 36.9 Critical voltage of helix unwinding, V.sub.c, V at 90 Hz 6.5 Spontaneous polarization, P.sub.S, nC/cm.sup.2 118.3 Switching on time, τ.sub.ON, μs 82

[0261] Comparative example showing results with known chiral component.

[0262] The Example shows effect of substitution in central core on tilt angle, c.f. with Example 46.

Example 51 Comparative Example

[0263]

TABLE-US-00070 TABLE 63 The composition of FLC-6-6 mixture. Content of the Components component, mol. % BPP-6 74.9 [00140] 25.1

TABLE-US-00071 TABLE 64 The properties of FLC-6-6 mixture (at 25° C.). Phase transitions [00141] Helix pitch, p.sub.0, nm 112 Tilt angle, θ, degree 36—below optimal value Spontaneous polarization, P.sub.S, nC/cm.sup.2 106—close to lowest margin Critical voltage of helix unwinding, V.sub.c, V at 10 Hz 9.7 Switching on time, τ.sub.ON, μs 150—close to upper margin

[0264] Comparative example showing results with known chiral component. The Example shows effect of substitution in central core on θ, c.f. with Example 46.

Example 52

[0265]

TABLE-US-00072 TABLE 65 The composition of FLC-DFT-1 mixture. Content of the Components component, mol. % DFT 75.2 [00142] 24.8

TABLE-US-00073 TABLE 66 The properties of FLC-DFT-1 mixture (at 25° C.). Phase transitions [00143] Helix pitch, p.sub.0, nm 260—over the optimal value

[0266] The example shows effect of the host. The chiral component is poor compatible with the host DFT, T.sub.SmC* reduced to 36° C. and HTP reduces more than 2.5 times

Example 53

[0267]

TABLE-US-00074 TABLE 67 The composition of FLC-3DFT-1 mixture. Content of the Components component, mol. % BPP-3 56.3 DFT 18.8 [00144] 24.9

TABLE-US-00075 TABLE 68 The properties of FLC-3DFT-1 mixture (at 25° C.). Phase transitions [00145] Tilt angle, 38.5 θ, degree Helix pitch, 160—over the optimal value p.sub.0, nm

[0268] The example shows effect of the host.

[0269] The chiral component is poor compatible with the host DFT, T.sub.SmC* reduced to 61° C. and HTP reduces more than 1.5 times

Example 54

[0270]

TABLE-US-00076 TABLE 69 The composition of FLC-3DFT-2 mixture. Content of the Components component, mol. % BPP-3 44.9 DFT 30.0 [00146] 25.1

TABLE-US-00077 TABLE 70 The properties of FLC-3DFT-2 mixture (at 25° C.). Tilt angle, θ, degree 36.5 - below optimal value Helix pitch, p.sub.0, nm 212 - over the optimal value

[0271] The example shows effect of the host. The chiral component is poor compatible with the host DFT−T.sub.SmC* reduced to 55° C. and HTP reduces more than 2 times.

Example 55

[0272]

TABLE-US-00078 TABLE 71 The composition of FLC-DFT-2 mixture. Content of the Components component, mol. % DFT 75.2 [00147] 24.8

TABLE-US-00079 TABLE 72 The properties of FLC-DFT-2 mixture (at 25° C.). Phase transitions [00148] Helix pitch, 175—over the optimal value p.sub.0, nm

[0273] The example shows effect of the host. The chiral component is poor compatible with the host DFT, T.sub.SmC* reduced to 55° C. and HTP reduces more than 1.5 times. The mixture was unstable upon storage, part of the chiral components precipitates with time.

Summary of Examples

[0274] The key parameters of the FLC materials were optimized by varying the chemical structure of their components and carefully matching the length of both central core and terminal chains for chiral components and for the achiral host.

[0275] As it can be seen from Examples, the high enough spontaneous polarization and acceptably short helix pitch is observed for the mixtures where chiral component has the combination of highly polar groups (O and CF.sub.3) at chiral centre with neighboring ester function. Chiral compounds possessing at chiral centre only polar ether function (—O— group) and low-polar CH.sub.3 groups show considerably less twisting and polarization.

[0276] Long enough terminal alkyls in chiral components, which are longer than similar groups in the achiral host also favors to the high twisting and short helix pitch. However, the longer terminal alkyls reduce the tilt angle. And vice versa, when terminal alkyl chains are shorter, the HTP slightly decreases whereas tilt angle increases.

[0277] In all examples chiral compounds bearing polar atoms (lateral fluorine(s) or heterocyclic N atom) in the central core induced higher tilt angle than unsubstituted in core analogs. This effect is more pronounced when these polar groups are located rather at the ends of central core than in its middle.

[0278] Among suitable achiral hosts, biphenylpyrimidines (BPP) are preferable in comparison to laterally fluorinated terphenyls (DFT) or two-rings phenylpyrimidines (PP-7). Individually, the DFT host appears less compatible with proposed set of the chiral components than BPP. The DFT hosts notably reduce of upper limit of T.sub.SmC* phase, whereas this temperature only slightly changes in the mixtures of CC with BPPs, in some cases it even increases. However, DTF host can be used in a moderately low concentrations (˜25 mol. %) with BPP in order reduce melting point of the mixture.

[0279] In the case of the PP7 Host, when it used individually with Chiral components, the HTP is not low and induced helix not enough tight to be used in DHFLC. In the mixtures PP7 with BPPs effect of melting point reduction became obvious only at high content of PP7, where its effect on HTP reduction is dominated.

INDUSTRIAL APPLICABILITY

[0280] The disclosed compound and liquid crystal composition may be used for electro-optical devices exploiting the DHFLC effect. This is applicable to industries such as display and photonic industries where the compound and liquid crystal composition can be used for LCD displays.

[0281] It will be apparent that various other modifications and adaptations of the invention will be apparent to the person skilled in the art after reading the foregoing disclosure without departing from the spirit and scope of the invention and it is intended that all such modifications and adaptations come within.

[0282] Key parameters of present invention (FLC) with that of current technologies.

TABLE-US-00080 TABLE 73 The comparison among FLC and Other NLCs Technologies Response Material time Pitch Alignment Contrast Hysteresis DHFLCs ~100 μs <<cell gap Planar ~800:1 NO (Current invention) SSFLC ~50 μs >cell gap Planar ~100:1 YES Kerr ~100 μs <<cell gap Vertical ~1000:1  NO Effect FLC ESHFLC ~50 μs ≤cell gap Planar ~10000:1  NO

REFERENCES

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