WO2005105952A1 - Liquid crystal compounds, liquid crystal medium and liquid crystal display - Google Patents

Abstract

The instant invention relates to mesogenic compounds which comprise a phenyl ring, which is bearing two mesogenic groups in otho position to each other, preferably of formula (I) wherein the parameters are as specified in the text. The instant invention further relates to mesogenic media, preferably liquid crystal media showing a blue phase and their use in electro-optical light modulation elements and their respective use in displays, as well as to such devices.

Description

Liquid Crystal Compounds, Liquid Crystal Medium and Liquid Crystal Display

Field of the invention

The present invention relates to mesogenic compounds, mesogenic media and to electro-optical displays comprising these mesogenic media as light modulation media, in particular to displays which are operated at a temperature at which the mesogenic modulation media are in an optically isotropic phase, preferably in a blue phase.

Problem to be solved and state of the art

Electro-optical displays and mesogenic light modulation media, which are in the isotropic phase when being operated in the display are described in DE 102 17273 A. Electro-optical displays, and mesogenic light modulation media, which are in the optically isotropic blue phase, when being operated in the display are described in DE 103 13 979.6, which is not yet laid open.

The mesogenic media and displays described in these references provide several significant advantages compared to well-known and widely used displays using liquid crystals in the nematic phase, like for example liquid crystal displays (LCDs) operating in the twisted nematic (TN)-, the super twisted nematic (STN)-, the electrically controlled birefringence (ECB)- mode with its various modifications and the in-pjane switching (IPS)-mode. Amongst these advantages are most pronounced their much faster switching times, and significantly wider optical viewing angle.

Whereas, compared to displays using mesogenic media in another liquid crystalline phase, as e.g. in the smectic phase in surface stabilized ferroelectric liquid crystal displays (SSF LCDs), the displays of DE 102 17 273.0 and DE 103 13 979 are much easier to be produced. For example, they do not require a very thin cell gap in the first place and the electro-optical effect is not very sensitive to small variations of the cell gap as well. However, the liquid crystal media described in these mentioned patent applications still require operating voltages, which are not low enough for some applications. Further the operating voltages of these media vary with temperature, and it is generally observed, that at a certain temperature the voltage dramatically increases with increasing temperature. This limits the applicability of liquid crystal media in the blue phase for display applications. A further disadvantage of the liquid crystal media described in these patent applications is their moderate reliability which is insufficient for very demanding applications. This moderate reliability may be for example expressed in terms of the voltage holding ratio parameter (VHR), which in liquid crystal media as described above may be below 90%.

Some compounds and compositions have been reported which possess a blue phase between the cholesteric phase and the isotropic phase and can usually be observed by optical microscopy. These compounds or compositions for which the blue phases are observed are typically single mesogenic compounds or mixtures showing a high chirality. However, generally the blue phases observed only extend over a very small temperature range, which is typically less than 1 degree centigrade (Kelvin) wide.

Nakata, Michi et al., Physical Review E, Vol 68, 041710-1 to -6 report the influence of the compound

on the phase sequence of strongly chiral cholesteric liquid crystals, which, however exhibit a blue pase at elevated temperatures only.

In order to operate the novel fast switching display mode of DE 103 13 979.6, the light modulation medium to be used has to be in the blue phase over a broad range of temperatures encompassing ambient temperature, however. Thus, a light modulation medium possessing a blue phase which is as wide as possible and conveniently located is required.

Therefore there is a strong need for a modulation medium with a blue phase with a wide phase range, which may be achieved either by an appropriate mixture of mesogenic compounds themselves or, preferably by mixing a host mixture with appropriate mesogenic properties with a single dopant or a mixture of dopants that stabilises the blue phase over a wide temperature range.

Summarizing, there is a need for liquid crystal media, which can be operated in liquid crystal displays which are operated at temperatures where the media is in the blue phase, which provide the following technical improvements:

- a reduced operating voltage,

- a reduced temperature dependency of the operating voltage and

- an improved reliability, e.g. VHR.

Present invention

Surprisingly, it now has been found that mesogenic compounds with a molecular structure comprising of a phenyl ring, which is bearing two mesogenic groups in otho position to each other, which are preferably identical to each other, and preferably the mesogenic compounds are substituted by one cyclic group or by two noncyclic groups on the opposite side of the two mesogenic groups mentioned, are suitable to considerably enhance the range of temperatures over which the blue phase is stable or even induce a blue phase in respective mesogenic hosts, which do not show such a phase on their own. Preferably the mesogenic hosts are liquid crystalline hosts. The two mesogenic groups do each contain at least one ring element, which is preferably selected from the group of four -, five -, six - or seven -, preferably of five - or six -, membered rings, which optionally are linked to one or more ring elememts selected from this group of ring elements by a direct bond or a linking group.

In a preferred embodiment the compounds according to the present invention are chiral compounds, preferably they comprise at leasrt one chirally substituted atom and most preferably a chirally substituted C-atom.

Preferably these compounds are of formula I

wherein

12

FT11 and R are, independently of each other, H, F, Cl, CN, NCS, SF₅ , SO₂CF₃ or alkyl which is straight chain or branched, preferably has 1 to 20 C-atoms, is unsubstituted, mono- or poly-substituted by F, Cl, or CN, and in which one or more non-adjacent CH₂ groups are optionally replaced, in each case independently from one another, by -0-, -S-, -NH-, -NR⁰¹-, -SiR⁰¹R⁰²-, -CO-, -COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, -CY⁰¹=CY⁰²- or -C≡C- in such a manner that O and/or S atoms are not linked directly to one another, preferably H, Halogen, n-alkyl, n-alkoxy with 1 to 9 C-atoms preferably 2 to 5 C-atoms, alkenyl, alkenyloxy or alkoxyalkyl with 2 to 9 C-atoms, preferably with 2 to 5 C- atoms or CN, NCS, halogen, preferably F, Cl, halogenated alkyl, alkenyl or alkoxy, preferably mono-, di fluorinated or oligofluorinated alkyl, alkenyl or alkoxy, especially preferred CF₃, OCF₂H or OCF₃,

R¹³ and R¹⁴ have, independently of each other, one of the meanings ggiivveenn ffoorr RR¹¹¹¹ oorr aalltteerrnnaattiivveellyy together form one of the cyclic groups CG-1 to CG-6

wherein p is an integer from 1 to 6

R¹⁵ and R¹⁶ have, independently of each other, one of the meanings given for R¹¹ or altenatively, again independently of each other, have one of the meanings given for

and — < A¹²> are, independently of each other

occurring more than once, also these are in each occurrence independently of each other, an aromatic and/or alicyclic ring, or a group comprising two or more fused aromatic or alicyclic rings, wherein these rings optionally contain one or more hetero atoms selected from N, O and/or S, and are optionally monosubstituted or polysubstituted by R, wherein

R has one of the meanings given for R¹¹ and preferably is

H. F, Cl, CN or alkyl preferably H, F or alkyl with 1 to 10 C-atoms,

Z¹¹ and Z¹² are, independently of each other, and in case Z¹¹ and/or

Z¹² are occurring more than once, also these are in each occurrence independently of each other, -CO-0-, -0-CO-, -S-CO-, -CO-S-, -CO-NR⁰¹-, -NR⁰¹-CO-, -OCH₂-, -CH≥O-, -SCH₂-, -CH₂S-, -CF₂0-, -OCF₂-, -CF₂S-, -SCF₂-, -CH₂CH₂-, -CF₂CH₂-, -CH₂CF₂-, -CF₂CF₂-, -CH=N-, -N=CH-, -N=N-, -CH=CR⁰¹-, -CR⁰¹=CH-, -CY⁰¹=CY⁰²-, -C≡C-, -(CH₂) ₄-, -CH=CH-CO-0-, -0-CO-CH=CH- or a single bond,

Y⁰ and Y⁰² are, independently of each other, F, Cl or CN, and alternatively one of them may be H,

R⁰¹ and R⁰² are, independently of each other, H or alkyl with 1 to 12

C-atoms,

Y¹¹ and Y ² are, independently of each other, H, F, Cl, CN or NCS, preferably H or F and n and m are, independently of each other 1 , 2, 3 or 4, preferably

1 , 2 or 3, most preferably 1 or 2.

Particularly preferred are compounds of formula I, wherein

at least one of Z¹¹ and Z¹², preferably at least one each of Z¹¹ and Z¹² and most preferably one each of Z¹¹ and Z¹², is -CO-0-, -0-CO-, -CH₂-0-, -0-CH₂-, -CF₂-0-, -0-CF₂- or -CH=CH-, most preferably -CF₂-0- or -0-CF₂- and/or preferably at least one, more preferably both of respective first groups Z¹¹ and Z¹², i.e. in case there are more than one group of Z¹¹ and/or of Z¹² the respetive groups bound to the central phenyl ring of the molecules is preferably not -CO-O- and not -0-CO-, preferably it is, respectively they are selected from -CF₂-0-, -0-CF₂-, -CH=CH-, and a single bond, most preferably from -CF₂-0-, -0-CF₂- and a single bond, in particular a single bond and/or

identical to each other and at the same time, preferably, also R¹¹ and R¹² are identical to each other, rings A¹¹ and/or A¹² are, respectively is phenylene, that is optionally substituted by one or more groups R and/or - R is alkyl or alkoxy with 1 to 12, preferably 1 to 8 C-atoms, or alkenyl, alkenyloxy or alkynyl with 2 to 12, preferably 2 to 7 C-atoms and/or

R¹³ and R¹⁴ are identical with each other or

R¹³ and R¹⁴ together form one of the cyclic groups CG-1 to CG-6, preferably CG-2, CG-3 or CG-4.

In a preferred embodiment rings A¹¹ to A¹³ are, independently of each other, an aromatic or alicyclic ring, preferably a 5-, 6- or 7-membered ring, or a group comprising two or more, preferably two or three, fused aromatic or alicyclic rings, wherein these rings optionally contain one or more hetero atoms selected from N, O and/or S, and are optionally mono- or polysubstituted with L, wherein L is F, Cl, Br, CN, OH, N0₂, and/or an alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl group with 1 to 12 C atoms, wherein one or more H atoms are optionally replaced by F or Cl.

L is preferably F, Cl, CN, OH, N0₂, CH₃, C₂H₅, OCH₃, OC₂H₅, COCH₃,

COC₂H₅, COOCH₃, COOC₂H₅, CF₃, OCF₃, OCHF₂ or OC₂F₅, in particular F, Cl, CN, CH₃, C₂H₅, OCH₃, COCH₃ or OCF₃, most preferably F, Cl, CH₃, OCH₃ or COCH₃.

Preferred rings A¹¹ and A¹² are for example furane, pyrrol, thiophene, oxazole, thiazole, thiadiazole, imidazole, phenylene, cyclohexylene, cyclohexenylene, pyridine, pyrimidine, pyrazine, azulene, indane, naphthalene, tetrahydronaphthalene, decahydronaphthalene, tetrahydropyrane, anthracene, phenanthrene and fluorene.

Particularly preferably one or more of these rings A¹¹ and A¹² is, respectively are, selected from furane-2,5-diyl, thiophene-2,5-diyl, thienothiophene-2,5-diyl, dithienothiophene-2,6-diyl, pyrrol-2,5-diyl, 1 ,4- phenylene, azulene-2,6-diyI, pyridine-2,5-diyl, pyrimidine-2,5-diyl, naphthalene-2,6-diyl, 1 ,2,3,4-tetrahydro-naphthalene-2,6-diyl, indane-2,5- diyl, or 1 ,4-cyclohexylene wherein one or two non-adjacent CH₂ groups are optionally replaced by O and/or S, wherein these groups are unsubstituted, mono- or polysubstituted by L as defined above.

Preferably

and

independently of each other in each occurrence, are

0 wherein^"

R is alkyl with 1 to 12 C-atoms, preferably with 1 to 7 C- atoms, or alkenyl or alkynyl with 2 to 12 C-atoms, c preferably with 2 to 7 C-atoms, in both of which one or more non-adjacent -CH₂- groups, not adjacent to the phenyl ring, may be replaced by -0- and/or -CH=CH- and/or one or more H-atoms may be replaced by halogen, preferably by F and preferably is alkyl,_Q preferably methyl, ethyl or propyl, preferably methyl,

or their mirror images

and most preferably at least one of them, in particular at least one each ofc them, is

In a preferred embodiment of the present invention at least one of the groups 5

preferably both of them, contains only monocyclic rings A¹¹ and A¹². Very preferably this is a group containing one or two 5- and/or 6-membered rings.

Preferred sub-formulae for this group are listed below. For reasons of simplicity, Phe in these groups is 1 ,4-phenylene, PheL is a 1 ,4-phenylene group which is substituted by 1 to 4 groups L as defined above, Cyc is 1 ,4- cyclohexylene, Pyd is pyridine-2,5-diyl and Pyr is pyrimidine-2,5-diyl. The following list of preferred groups is comprising the sub formulae A-1 to A-20 as well as their mirror images,

-Phe- A-1

-Pyd- A-2

-Pyr- A-3

-PheL- A-4

-Cyc- A-5

-Phe-Z-Cyc- A-6

-Cyc-Z-Cyc- A-7

-PheL-Cyc- A-8

-Phe-Z-Phe- A-9

-Phe-Z-Pyd- A-10

-Pyd-Z-Phe- A-11

-Phe-Z-Pyr- A-12

-Pyr-Z-Phe- A-13

-PheL-Z-Phe- A-14

-PheL-Z-Pyd- A-15

-PheL-Z-Pyr- A-16

-Pyr-Z-Pyd- A-17

-Pyd-Z-Pyd- A-18

-Pyr-Z-Pyr- A-19

-PheL-Z-PheL- A-20 In these preferred groups Z has the meaning of Z 1 as given in formula Preferably Z is -CF₂-0- or -0-CF₂- or a single bond.

Very preferably, at least one of the groups

preferably both of them, are selected from the following formulae la to Im and their respective mirror images

wherein L has the meaning given above and r and s are independently of each other, 0, 1 , 2, 3 or 4, preferably 0, 1 or 2.

- _ jn these preferred formulae is very preferably

'

with L having each independently one of the meanings given above.

Especially preferred compounds of formula I comprise at least one group each in rings A¹¹ and A¹² of the formula

wherein r is 1 or 2.

Further preferred compounds of formula I comprise at least one group each in rings A¹¹ and A¹² of the formula

— < )>— wherein r is 2 and/or at least one group each of the formula At wherein r is 0, 1 or 2.

Very preferably, at least one of the groups

preferably both of them, are

AΛ_AΛ_AΛ

^{35 "} Z^ ^⁰^⁰

or their respective mirror images,

wherein the 1 ,4-phenylene rings may optionally be substituted by R or L, preferably by alkyl, preferably by methyl, and/or by alkoxy and/or by halogen, preferably F.

More preferably at least one of the groups

preferably both of them, are

or their respective mirror images.

In a preferred embodiment of the present invention R¹³ and R ι1'4 together are forming a divalent radical selected from the following group of formulae

wherein the parameters have the respective meanings given above.

An alkyl or an alkoxy radical, i.e. an alkyl where the terminal CH₂ group is replaced by -0-, in this application may be straight-chain or branched. It is preferably straight-chain, has 1, 2, 3, 4, 5, 6, 7 or 8 carbon atoms and accordingly is preferably methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy, heptoxy, or octoxy, furthermore nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy or tetradecoxy, for example.

Oxaalkyl, i.e. an alkyl group in which one non-terminal CH₂ group is replaced by -0-, is preferably straight-chain 2-oxapropyl (= methoxy- methyl), 2- (= ethoxymethyl) or 3-oxabutyl (= 2-methoxyethyl), 2-, 3-, or 4- oxapentyl, 2-, 3-, 4-, or 5-oxahexyl, 2-, 3-, 4-, 5-, or 6-oxaheptyl,

2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl or 2-, 3-, 4-, 5-, 6-,7-, 8- or 9-oxadecyl, for example.

An alkenyl group, i.e. an alkyl group wherein one or more CH₂ groups are replaced by -CH=CH-, may be straight-chain or branched. It is preferably straight-chain, has 2 to 10 C atoms and accordingly is preferably vinyl, prop-1-, or prop-2-enyl, but-1-, 2- or but-3-enyl, pent-1-, 2-, 3- or pent- 4-enyl, hex-1-, 2-, 3-, 4- or hex-5-enyl, hept-1-, 2-, 3-, 4-, 5- or hept-6-enyl, oct-1 -, 2-, 3-, 4-, 5-, 6- or oct-7-enyl, non-1-, 2-, 3-, 4-, 5-, 6-, 7- or non- 8-enyl, dec-1-, 2-, 3-, 4-, 5-, 6-, 7-, 8- or dec-9-enyl.

Especially preferred alkenyl groups are C₂-C₇-1 E-alkenyl, C₄-C₇-3E- alkenyl, C₅-C₇-4-alkenyl, C₆-C₇-5-alkenyl and C₇-6-alkenyl, in particular C₂-C -1 E-alkenyl, C₄-C₇-3 E-alkenyl and C₅-C₇-4-alkenyl. Examples for particularly preferred alkenyl groups are vinyl, 1 E-propenyl, 1 E-butenyl,

1 E-pentenyl, 1 E-hexenyl, 1 E-heptenyl, 3-butenyl, 3E-pentenyl, 3E-hexenyl, 3E-heptenyl, 4-pentenyl, 4Z-hexenyl, 4E-hexenyl, 4Z-heptenyl, 5-hexenyl, 6-heptenyl and the like. Groups having up to 5 C atoms are generally preferred. In an alkyl group, wherein one CH₂ group is replaced by -O- and one by -CO-, these radicals are preferably neighboured. Accordingly these radicals together form a carbonyloxy group -CO-O- or an oxycarbonyl group -0-CO-. Preferably such an alkyl group is straight-chain and has 2 to 6 C atoms.

It is accordingly preferably acetyloxy, propionyloxy, butyryloxy, pentanoyloxy, hexanoyloxy, acetyloxymethyl, propionyloxymethyl, butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl, 2-propionyloxy- ethyl, 2-butyryloxyethyl, 3-acetyloxypropyl, 3-propionyloxypropyl,

4-acetyloxybutyl, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, methoxycarbonyl methyl, ethoxy- carbonylmethyl, propoxycarbonylmethyl, butoxycarbonylmethyl, 2-(methoxycarbonyl)ethyl, 2-(ethoxycarbonyl)ethyl, 2-(propoxy- carbonyl)ethyl, 3-(methoxycarbonyl)propyl, 3-(ethoxycarbonyl)propyl, 4-(methoxycarbonyl)-butyl.

An alkyl group wherein two or more CH₂ groups are replaced by -O- and/or -COO-, it can be straight-chain or branched. It is preferably straight-chain and has 3 to 12 C atoms. Accordingly it is preferably bis-carboxy-methyl, 2,2-bis-carboxy-ethyl, 3,3-bis-carboxy-propyl, 4,4-bis-carboxy-butyl, 5,5-bis-carboxy-pentyl, 6,6-bis-carboxy-hexyl, 7,7-bis-carboxy-heptyl, 8,8-bis-carboxy-octyI, 9,9-bis-carboxy-nonyl, 10,10-bis-carboxy-decyl, bis- (methoxycarbonyl)-methyl, 2,2-bis-(methoxycarbonyl)-ethyl, 3,3-bis- (methoxycarbonyl)-propyl, 4,4-bis-(methoxycarbonyl)-butyl, 5,5-bis- (methoxycarbonyl)-pentyl, 6,6-bis-(methoxycarbonyl)-hexyl, 7,7-bis- (methoxycarbonyl)-heptyl, 8,8-bis-(methoxycarbonyl)-octyl, bis- (ethoxycarbonyl)-methyl, 2,2-bis-(ethoxycarbonyl)-ethyl, 3,3-bis- (ethoxycarbonyl)-propyl, 4,4-bis-(ethoxycarbonyl)-butyl, 5,5-bis- (ethoxycarbonyl)-hexyl.

A alkyl or alkenyl group that is monosubstituted by CN or CF₃ is preferably straight-chain. The substitution by CN or CF₃ can be in any desired position.

An alkyl or alkenyl group that is at least monosubstituted by halogen, it is preferably straight-chain. Halogen is preferably F or Cl, in case of multiple substitution preferably F. The resulting groups include also perfluorinated groups. In case of monosubstitution the F or Cl substituent can be in any desired position, but is preferably in ω-position. Examples for especially preferred straight-chain groups with a terminal F substituent are fluoromethyl, 2-fluoroethyl, 3-fluoropropyl, 4-fluorobutyl, 5-fluoropentyl, 6-fluorohexyl and 7-fluoroheptyl. Other positions of F are, however, not excluded.

Halogen means F, Cl, Br and 1 and is preferably F or Cl, most preferably F.

Each of R¹¹ to R¹⁶, R, R\ R⁰¹ and R⁰² may be a polar or a non-polar group. In case of a polar group, it is preferably selected from CN, SF₅, halogen, OCH₃, SCN, COR⁵, COOR⁵ or a mono- oligo- or polyfluorinated alkyl or alkoxy group with 1 to 4 C atoms. R⁵ is optionally fluorinated alkyl with 1 to 4, preferably 1 to 3 C atoms. Especially preferred polar groups are selected of F, Cl, CN, OCH₃, COCH₃, COC₂H₅, COOCH₃, COOC₂H₅, CF₃, CHF₂, CH₂F, OCF₃, OCHF₂, OCH₂F, C₂F₅ and OC₂F₅₍ in particular F, Cl, CN, CF₃, OCHF₂ and OCF₃. In case of a non-polar group, it is preferably alkyl with up to 15 C atoms or alkoxy with 2 to 15 C atoms.

Each of R¹¹ to R¹⁶, R, R', R⁰¹ and R⁰² may be an achiral or a chiral group. In case of a chiral group it is preferably of formula I^*:

-Q¹-CH-Q²

Q°

wherein

Q¹ is an alkylene or alkylene-oxy group with 1 to 9 C atoms or a single bond,

Q² is an alkyl or alkoxy group with 1 to 10 C atoms which may be unsubstituted, mono- or polysubstituted by F, Cl, Br or CN, it being also possible for one or more non-adjacent CH₂ groups to be replaced, in each case independently from one another, by -C≡C-, -0-, -S-, -NH-, -N(CH₃)-, -CO-, -COO-, -OCO-, -OCO-0-, -S-CO- or -CO-S- in such a manner that oxygen atoms are not linked directly to one another,

Q³ is F, Cl, Br, CN or an alkyl or alkoxy group as defined for Q² but being different from Q².

In case Q¹ in formula I* is an alkylene-oxy group, the O atom is preferably adjacent to the chiral C atom.

Preferred chiral groups of formula I* are 2-alkyl, 2-alkoxy, 2-methylalkyl, 2- methylalkoxy, 2-fluoroalkyl, 2-fluoroalkoxy, 2-(2-ethin)-alkyl, 2-(2-ethin)-alkoxy, 1 ,1 ,1-trifluoro-2-alkyl and 1 ,1 ,1-trifluoro-2-alkoxy.

Particularly preferred chiral groups I^* are 2-butyl (=1-methylpropyl), 2- methylbutyl, 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, in particular 2-methylbutyl, 2-methylbutoxy, 2-methylpentoxy, 3- methylpentoxy, 2-ethylhexoxy, 1-methylhexoxy, 2-octyloxy, 2-oxa-3- methylbutyl, 3-oxa-4-methylpentyl, 4-methylhexyl, 2-hexyl, 2-octyl, 2-nonyl, 2-decyl, 2-dodecyl, 6-methoxyoctoxy, 6-methyloctoxy, 6- methyloctanoyloxy, 5-methylheptyloxycarbonyl, 2-methylbutyryloxy, 3- methylvaleroyloxy, 4-methylhexanoyloxy, 2-chlorpropionyloxy, 2-chloro-3- methylbutyryloxy, 2-chloro-4-methylvaleryloxy, 2-chloro-3-methylvaleryloxy, 2-methyl-3-oxapentyl, 2-methyl-3-oxahexyl, 1 -methoxypropyl-2-oxy, 1- ethoxypropyl-2-oxy, 1 -propoxypropyl-2-oxy, 1 -butoxypropyl-2-oxy, 2- fluorooctyloxy, 2-fluorodecyloxy, 1 ,1 ,1-trifluoro-2-octyloxy, 1 ,1 ,1-trifluoro-2- octyl, 2-fluoromethyloctyloxy for example. Very preferred are 2-hexyl, 2- octyl, 2-octyloxy, 1 ,1 ,1-trifluoro-2-hexyl, 1 ,1 ,1-trifluoro-2-octyl and 1 ,1 ,1- trifluoro-2-octyloxy.

In addition, compounds containing an achiral branched alkyl group may occasionally be of importance, for example, due to a reduction in the tendency towards crystallization. Branched groups of this type generally do not contain more than one chain branch. Preferred achiral branched groups are isopropyl, isobutyl (= methylpropyl), isopentyl (= 3-methylbutyl), isopropoxy, 2-methyl-propoxy and 3-methylbutoxy. ln a preferred embodiment of the present invention one or more of R¹¹ to R¹⁶, R, FT, R⁰ and R⁰², preferably one of R¹³ and R¹⁴ or both, are -SG-PG.

The polymerisable or reactive group PG is preferably selected from

CH₂=CW²-(0)_kι-, CH₃-CH=CH-0-, (CH₂=CH)₂CH-OCO-, (CH₂=CH-CH₂)₂CH-OCO-, (CH₂=CH)₂CH-0-, (CH₂=CH-CH₂)₂N-, HO-CW²W³-, HS-CW²W³-, HW²N-, HO-CW²W³-NH-, CH₂=CW -CO-NH-, CH₂=CH-(COO)_k1-Phe-(0)_k2-, Phe-CH=CH-, HOOC-, OCN-, and W⁴W⁵W⁶Si-, with W¹ being H, Cl, CN, phenyl or alkyl with 1 to 5 C-atoms, in particular H, Cl or CH₃, W² and W³ being independently of each other H or alkyl with 1 to 5 C-atoms, in particular methyl, ethyl or n- propyl, W⁴, W⁵ and W^δ being independently of each other Cl, oxaalkyl or oxacarbonylalkyl with 1 to 5 C-atoms, Phe being 1 ,4-phenylene and ki and k₂ being independently of each other 0 or 1.

Especially preferably PG is a vinyl group, an acrylate group, a methacrylate group, an oxetane group or an epoxy group, especially preferably an acrylate or methacrylate group.

As for the spacer group SG all groups can be used that are known for this purpose to those skilled in the art. The spacer group SG is preferably of formula SG'-X, such that PG-SG- is PG-SG'-X-, wherein

SG' is alkylene with up to 20 C atoms which may be unsubstituted, mono- or poly-substituted by F, Cl, Br, I or CN, it being also possible for one or more non-adjacent CH₂ groups to be replaced, in each case independently from one another, by -O-, -S-, -NH-, -NR⁰¹-, -SiR⁰¹R⁰²-, -CO-, -COO-, -OCO-, -OCO-0-, -S-, -CO-, -CO-S-, -CH=CH- or -C≡C- in such a manner that O and/or S atoms are not linked directly to one another, X is -0-, -S-, -CO-, -COO-, -OCO-, -0-COO-, -CO-NR⁰¹-, -NR⁰¹-CO-, - OCH₂-, -CH₂0-, -SCH₂-, -CH₂S-, -CF₂0-, -OCF₂-, -CF₂S-, -SCF₂-, -CF₂CH₂-, -CH₂CF₂-, -CF₂CF₂-, -CH=N-, -N=CH-, -N=N-, -CH=CR⁰¹-, -CY⁰¹=CY⁰²-, -OC-, -CH=CH-COO-, -OCO-, -CH=CH- or a single bond, and

R⁰¹, R⁰², Y⁰¹ and Y⁰² have one of the respective meanings given above.

X is preferably -0-, -S-, -OCH₂-, -CH₂0-, -SCH₂-, -CH₂S-, -CF₂0-, -OCF₂-, -CF₂S-, -SCF₂-, -CH₂CH₂-, -CF₂CH₂-, -CH₂CF₂-, -CF₂CF₂-,

-CH=N-, -N=CH-, -N=N-, -CH=CR⁰-, -CY⁰²=CY⁰²-, -C≡C- or a single bond, in particular -0-, -S-, -C≡C-, -CY⁰¹=CY⁰²- or a single bond, very preferably a group that is able to from a conjugated system, such as -C≡C- or -CY⁰¹=CY⁰²-, or a single bond.

Typical groups SG' are, for example, -(CH₂)_P-, -(CH₂CH₂0)_q -CH₂CH₂-, -CH₂CH₂-S-CH₂CH₂- or -CH₂CH₂-NH-CH₂CH₂- or -(SiR°R⁰⁰-O)_p-, with p being an integer from 2 to 12, q being an integer from 1 to 3 and R°, R⁰⁰ and the other parameters having the meanings given above.

Preferred groups SG' are ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylene-thioethylene, ethylene-N-methyl-iminoethylene, 1 -methylalkylene, ethenylene, propenylene and butenylene for example.

In another preferred embodiment SG' is a chiral group of formula I^*':

*

4

-Q¹- -Q

wherein

Q¹ and Q³ have the meanings given in formula I*, and Q« is an alkylene or alkylene-oxy group with 1 to 10 C atoms or a single bond, being different from Q¹,

with Q being linked to the polymerisable group PG.

Further preferred are compounds with one or two groups PG-SG- wherein SG is a single bond.

In case of compounds with two groups PG-SG, each of the two polymerisable groups PG and the two spacer groups SG can be identical or different.

Preferably the liquid crystalline media according to the instant invention contain a component A comprising, preferably predominantly consisting of and most preferably entirely consisting of compounds of formula I.

The compounds of formula I preferably are prepared according to the following scheme.

Scheme I

H₂0, K₂C0₃

toluene, H₂0, K₂C0₃

wherein the parameters have the repective meanings given above and the boronates with the mesogeneous moieties. are obtainable by conventional methods.

By this sequence of reactions non-symmetric compounds ( e.g. wherein -(Z¹¹-A¹¹)_n-R¹¹ is different from -(Z¹²-A¹²)_m-R¹² are prepared by two subsequent couplings.

Comprising in this application means in the context of compositions that the entity referred to, e.g. the medium or the component, contains the compound or compounds in question, preferably in a total concentration of 10 % or more and most preferably of 20 % or more.

Predominantly consisting, in this context, means that the entity referred to contains 80 % or more, preferably 90 % or more and most preferably 95 % or more of the compound or compounds in question.

Entirely consisting, in this context, means that the entity referred to contains 98 % or more, preferably 99 % or more and most preferably 100.0 % of the compound or compounds in question.

The concentration of the compounds according to the present application are contained in the media according to the present application preferably is in the range from 0.5% or more to 30% or less, more preferably in the range from 1 % or more to 20% or less and most preferably in the range from 5% or more to 12% or less. The compounds of formula I are preferably selected from the group of sub- formulae 1-1 to 1-11

30

35

35

wherein the parameters have the respective meanings given under formula I above and preferably

R¹¹ and R¹² are, independently of each other, F, Cl, CN, NCS, CF₃, OCF₃, alkyl, alkoxy, alkenyl or alkynyl, preferably F, Cl, alkyl or alkoxy, and in formulae 1-1 to I-6 are preferably F, Cl, CN, NCS, CF₃ or OCF₃, and in formulae 1-1 to I-6 are preferably alkyl, alkoxy, alkenyl or alkynyl,

R and R are, independently of each other, alkyl, alkoxy, alkenyl or alkynyl and in case they are linkrd to a C-atom also may be H, preferably they are alkyl or H,

L¹¹ to L^11"' and L¹² to L^12"' are, independently of each other, H or F, preferably F and

X¹¹ and X¹² are, independently of each other, F, Cl, CN, CF₃, OCF₃ or NCS, preferably F, CF₃ or CN, most preferably the are identical with each other,

and chiral compounds of these compounds are encompassed too.

ln a preferred embodiment the mesogenic modulation media according to the instant invention comprise

- a component A, preferably in a concentration of 1 % to 25 %,

5 preferably up to 10 %, by weight, comprising, preferably predominantly consisting of and most preferably entirely consisting of, one compound or more compounds of the formula I given above and

- optionally a dielectrically positive component B comprising, preferably 1 o predominantly consisting of and most preferably entirely consisting of one compound or of more compounds of formula II

wherein

20 R² has the meaning given under formula I for R¹¹,

A²¹, A²² and A²³ are, each independently of each other,

whereby each of A²¹ and A²² may have the same or a

„,. different meaning, if present twice, Z and Z are, each independently of each other, a single bond,

-(CH ) )-, -CH₂CH₂-, -CF₂-CF₂-, -CF -CH -, -CH₂-CF₂-, -CH=CH-, -CF=CF-, -CF=CH-, -(CH₂)₃0-, -0(CH₂)₃-, -CH=CF-, -C≡C-, -CH₂0-, -OCH₂-, -CF₂0-, -OCF₂-, -CO-O- or -0-CO-, whereby each of Z²¹ and Z²² may have the same or a different meaning if present twice,

X² is halogen, -CN, -NCS, -SF₅, -S0₂CF₃, alkyl, alkenyl, aikenyloxy or alkylalkoxy or alkoxy radical each mono- or polysubstituted by CN and/or halogen,

L²¹ and L²² are, each independently of each other, H or F, and

m is O, 1 or 2,

is O, 1 , 2 or 3,

o is 0, 1 or 2, preferably 0 or 1 and

m + n + o is 3 or less, preferably 2 or less,

- optionally a component C, preferably in a concentration of 1 % to 25 %, generally up to 10 % by weight, comprising, preferably predominantly consisting of and most preferably entirely consisting of one compound or of more compounds of formula III

wherein

a, b, c and d are each independently of each other 0, 1 or 2, whereby

a + b + c + d is 4 or less, A³¹ A³² A³³ and A are, each independently of each other,

whereby each of A³¹, A³², A³³ and A³⁴ may have the same or a different meaning if present twice,

_Z31 _{) Z}32_{) Z}33

and Z³⁴ are, each independently of each other, a single bond,

-(CH₂)₄)-, -CH₂CH -, -CF₂-CF₂-, -CF₂-CH -, -CH₂-CF₂-, -CH=CH-, -CF=CF-, -CF=CH-, -(CH₂)₃0-, -0(CH₂)₃-, -CH=CF-, -C≡D-, -CH₂0-, -OCH₂-, -CF₂0-, -OCF₂-, -CO-O- or -0-CO-, whereby each of Z³¹, Z³², Z³³ and Z 34 may have the same or a different meaning if present twice,

R³ is an alkyl or alkoxy radical having from 1 to 15 carbon atoms, wherein one or more methylene groups of said alkyl or alkoxy radical may be replaced independently of each other by -0-, -S-, -SiR^xR^y-, -CH=CH-, -C≡D-, -CO-O- and/or -O-CO- such that oxygen and/or sulfur atoms are not linked directly to each other, said alkyl or alkoxy radical being unsubstituted or mono-substituted with a -CN group or mono- or poly-substituted with halogen, preferably R¹¹ is a straight-chain alkyl, alkoxy, alkenyl, alkenyloxy or -0-alkylene-O-alkyl radical with up to 10 carbon atoms, said radicals being unsubstituted or mono- or poly-substituted with halogen,

L³¹, L³², L³ and L³⁴ are each independently of each other hydrogen, halogen, a CN group, an alkyl or alkoxy radical having from 1 to 15 carbon atoms wherein one or more methylene groups of said alkyl or alkoxy radical may be replaced independently of each other by -0-, -S-,

-SiR^xR^y-,> -CH=CH-, -C≡D-, -CO-O- and/or -O-CO- such that oxygen and/or sulfur atoms are not linked directly to each other, said alkyl or alkoxy radical being unsubstituted or mono-substituted with a -CN group or mono- or poly-substituted with halogen, with the proviso that at least one of L³¹, L³², L³³ and L³⁴ is not hydrogen,

X³ is F, Cl, CF₃, OCF₃, CN, NCS, -SF₅ or -S0₂-R^z,

R^x and R^y are independently of each other hydrogen or an alkyl radical having from 1 to 7 carbon atoms; preferably R^x and R^y are both methyl, ethyl, propyl or butyl, and

R^z is an alkyl radical having from 1 to 7 carbon atoms, said alkyl radical being unsubstituted or mono- or polysubstituted with halogen; preferably R² is CF₃, C₂F₅ or

- 1 -20 % by weight of component D comprising one chiral compound or more chiral compounds with a HTP of ≥ 20 μm.

The inventive mixtures contain 1-25 wt.%, preferably 2-20 wt.% and most preferably 3-15 wt.% of component A.

Preferred compounds of formula II are compounds selected of the group of formulae 11-1 to II-8, preferably of formulae II-4 and/or II-5:

and in particular of formula ll-8a

wherein the parameters have the respective meanings given under formula II and preferably

R is straight chain alkyl or alkoxy with up to six carbon atoms and

X² is F, CN, NCS, CF₃, SF₅ or OCF₃, preferably F or CN.

Especially preferred are compounds of the formulae II-5 and II-8.

The inventive mixtures contain 20-80 wt.% of the pyrane compounds of the formulae II, preferably 25-70 wt.% and especially preferred 30-60 wt.%.

In a preferred embodiment of the present invention the compounds of formula III are selected from the group of compounds of the formulae 111-1 to III-7

wherein the parameters have the respective meanings given under formula III and preferably

is 0 or 1 , d is 0, 1 or 2, preferably 0 or 1 , especially preferred 1 ;

R³ is an alkyl or alkoxy radical having from 1 to 15 carbon atoms or an alkenyl or alkenyloxy or -O-alkylene-O-alkyl radical having from 2 to 15 carbon atoms, wherein one or more methylene groups of each of said radicals may be replaced independently of each other by -S-, -SiR^xR^y-, -C≡D-, -CO-O- and/or -O-CO- such that oxygen and/or sulfur and/or Si atoms are not linked . directly to each other, said radicals being unsubstituted or mono-substituted with a -CN group or mono- or polysubstituted with halogen, preferably R³ is a straight- chain alkyl, alkoxy, alkenyl, alkenyloxy or -O-alkylene-O- alkyl radical with up to 10 carbon atoms, said radicals being unsubstituted or mono- or poly-substituted with halogen,

L³¹ , independently, has one of the meanings given for R³ and preferably is a straight-chain alkyl, alkoxy, alkenyl, alkenyloxy or -O-alkylene-O-alkyl radical with up to 10 carbon atoms, said radicals being unsubstituted or mono- or poly-substituted with halogen,

L³² , independently, has one of the meanings given for R³ or alternatively is hydrogen, halogen and preferably is

H, F, a straight-chain alkyl, alkoxy, alkenyl, alkenyloxy or -O-alkylene-O-alkyl radical with up to 10 carbon atoms, said radicals being unsubstituted or mono- or polysubstituted with halogen,

■ 35 . 36 •- > L³⁷, L³⁸

■ 39 I 39a 1— > 1— ! L^39b, and L^39c are, independently of each other, H or F and in formulae 111-1 to III-4 preferably at least L³⁵ is F and in formulae III-3 and III-4 preferably additionally L³⁸ is F, whereas in formula III-7 preferably additionally L³⁶ is F and in formulae III-5 and III-6 preferably at least both L and L^39b are F,

X³ is F, Cl, -CN, -NCS, -SF₅, -S0₂-R^z, an alkyl or alkoxy radical having from 1 to 15 carbon atoms, wherein one or more methylene groups of said alkyl or alkoxy radical may be replaced independently of each other by -0-, -S-, -SiR^xR^y-, -CH=CH-, -C≡C-, -CO-O- and/or -O-CO- such that oxygen and/or sulfur atoms are not linked directly to each other, said alkyl or alkoxy radical being unsubstituted or mono-substituted with a -CN group or mono- or poly-substituted with halogen; preferably X³ is F, Cl, CF₃, OCF₃, OCHF₂, NCS, SF₅ or -S0₂-R^z,

Y³ is an alkyl or alkoxy radical having from 1 to 15 carbon atoms or an alkenyl or alkenyloxy or -O-alkylene-O-alkyl radical having from 2 to 15 carbon atoms, wherein one or more methylene groups of each of said radicals may be replaced independently of each other by -S-, -SiR^xR^y-, -C≡C-, -CO-O- and/or -O-CO- such that oxygen and/or sulfur atoms are not linked directly to each other, said radicals being unsubstituted or mono- substituted with a -CN group or mono- or polysubstituted with halogen, preferably Y³¹ is an alkoxy, alkenyloxy or -O-alkylene-O-alkyl radical with up to 10 carbon atoms, said radicals being unsubstituted or mono- or poly-substituted with halogen; in particular Y³¹ has the same meaning as L³¹,

Y³² is hydrogen, halogen, an alkyl or alkoxy radical having from 1 to 15 carbon atoms or an alkenyl or alkenyloxy or -O-alkylene-O-alkyl radical having from 2 to 15 carbon atoms, wherein one or more methylene groups of each of said radicals may be replaced independently of each other by -S-, -SiR^xR^y-, -C≡C-, -CO-O- and/or -O-CO- such that oxygen and/or sulfur atoms are not linked directly to each other, said radicals being unsubstituted or mono-substituted with a -CN group or mono- or polysubstituted with halogen, preferably Y³² is H,

Z³³ and Z³⁴ are, independently of each other, a single bond,

-CH₂CH₂-, (-CH CH₂-)₂, -CF₂-CF₂-, -CF -CH₂-, -CH₂-CF₂-, -CH=CH-, -CF=CF-, -CF=CH-, -CH=CF-, -C≡D-, -CH₂0-, -OCH₂-, -CF₂0-, -OCF₂-, -CO-O- or -0-CO-, preferably Z³⁴ is a single bond, -C≡C-, -CF₂0- or -C0₂-, in particular a single bond or -CF₂0-, and in formulae III-3 and III-4 preferably one or both of Z³³ and Z³⁴ is a single bond, more preferably Z³³ and Z³⁴ are both a single bond or one of Z³³ and Z³⁴ alternatively is

-CF₂0- or -C0₂-,

R^x and R^y are independently of each other hydrogen or an alkyl radical having from 1 to 7 carbon atoms; preferably both R^x and R^y are methyl, ethyl, propyl or butyl;

R^z is an alkyl radical having from 1 to 7 carbon atoms, said alkyl radical being unsubstituted or mono- or polysubstituted with halogen; preferably R^z is CF₃, C₂F₅ or

whereby it is further preferred that at least one of R³, L³¹ and L³² is one of said straight-chain alkyl, alkoxy, alkenyl, alkenyloxy or -O-alkylene-O-alkyl radicals.

Suitable chiral compounds of component D are those which have an absolute value of the helical twisting power of 20 μm or more, preferably of 40 μm or more and most preferably of 60 μm or more. The HTP is measured in MLD-6260 at a temperature of 20°C.

The chiral component D comprises preferably one or more chiral compounds which have a mesogenic structure und exhibit preferably one or more mesophases themselves, particularly at least one cholesteric phase. Preferred chiral compounds being comprised in the chiral component D are, inter alia, well known chiral dopants like cholesteryl- nonanoate (CN), R/S-811 , R/S-1011 , R/S-2011 , R/S-3011 , R/S-401 1 , R/S-5011 , CB-15 (Merck KGaA, Darmstadt, Germany). Preferred are chiral dopants having one or more chiral moieties and one or more mesogenic groups or having one or more aromatic or alicyclic moieties forming, together with the chiral moiety, a mesogenic group. More preferred are chiral moieties and mesogenic chiral compounds disclosed in DE 34 25 503, DE 35 34 777, DE 35 34 778, DE 35 34 779, DE 35 34 780, DE 43 42 280, EP 01 038 941 and DE 195 41 820 that disclosure is incorporated within this application by way of reference. Particular preference is given to chiral binaphthyl derivatives as disclosed in EP 01 111 954.2, chiral binaphthol derivatives as disclosed in WO 02/34739, chiral TADDOL derivatives as disclosed in WO 02/06265 as well as chiral dopants having at least one fluorinated linker and one end chiral moiety or one central chiral moiety as disclosed in WO 02/06196 and WO 02/06195.

The controlling medium of the present invention has a characteristic temperature, preferably a clearing point, in the range from about -30 °C to about 80 °C, especially up to about 55 °C.

Preferred chiral compounds of the component D are selected from the group of the compounds D-l to D-lll.

wherein

R^a11, R^a12, are each independently from each other alkyl, oxalkyl,

R^a21, R^a22 alkoxy or alkenyl with up 9 carbon atoms with the

R^a31 and R^a32 provisos that

a) R^a11 + R^a12 b) R^a21 + R^a22

Preferably R^a11, R^a12, R^a21, R^a22, R^a31 and R^a32 are an alkyl group, especially a straight chain alkyl group.

Especially preferred are chiral binaphthyl derivates of the formulae D-IV,

Especially preferred are binaphthyl derivatives of the formulae D-IV-1 a to D-IV-1 c,

wherein

is single bond, -CH₂CH₂-, -COO-, -OCO-, -CF₂0-, -OCF₂-, -CH₂0-, -OCH₂-, -CF₂CF₂-, -CH=CH-, -C≡D- or -CF=CF-,

is 0, 1 or 2

R^L is hydrogen, an alkyl or alkoxy radical having from 1 to 15 carbon atoms wherein one or more methylene groups of said alkyl or alkoxy radical may be replaced independently of each other by -0-. -S-, -SiR Xr R>Y -, -CH=CH-, -C≡D-, -CO-O- and/or -O-CI- such that oxygen and/or sulfur atoms are not linked directly to each other, said alkyl or alkoxy radical being unsubstituted or mono- or poly-substituted with halogen,

Furthermore chiral binaphthyl derivates of the formulae D-V and D-VI are preferred

wherein Z and b have the above given meanings and X is

H, F, Cl, CN or has the meaning of R°\ R^2* and R^1* are each independently is F, Cl, OCF₃, CF₃, CN and L¹, L², L³ and L⁴ are each H or F. Z°^* denotes single bond, -C₂H₄-, -COO-, -OCO-, CH₂0-, -OCH₂-, -C₂F₄, -CH=CH-, -C≡D- or-CF=CF Especially preferred are chiral binaphthyl derivatives of the formulae D- V-2a to D-V-2f :

The inventive mixtures contain one ore more (two, three, four or more) chiral compounds in the range of 1-25 wt.%, preferably 2-20 wt.%. Especially preferred are mixtures containing 3-15 wt.% of a chiral compound.

Preferred embodiments are indicated below:

The medium comprises one, two or more compounds of formula I;

Component B preferably contains besides one compound ore more compounds of formula II one ester compound or more ester compounds of the formula Z

wherein R^z has the meaning given under formula I for R¹¹,

X^z is F, Cl, CN, NCS, OCF₃, CF₃ or SF₅.

Preferred compounds of the formula Z are selected from the group of compounds of formulae Z-1 to Z-14

35

wherein R has the meaning given under formula Z for R^ Especially preferred are mixtures containing 5 % to 35 %, preferably 10 % to 30 % and especially preferred 10 % to 20 % of compounds of formula Z, preferably selected from the group of formulae Z-1 to Z-14.

The component B preferably contains additionally one or more compounds selected from the group of ester compounds of formulae N-1 to N-10

Alkyl-C≡C— O >— COO — O . /— CN N-1

F

Alkyl-C≡C— < O )— COO- A CN N-2

wherein

has the meaning given under formula I for R 11 and

"Alkyl" is alkyl with 1 to 7 C-atoms, preferably n-alkyl.

The medium component B additionally comprises one or more compounds selected from the group consisting of the general formulae IV to VIII

wherein

R^L is n-alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl, each having up to 9 carbon atoms,

X^u is CN, SF₅, NCS, S0₂CF₃, F, Cl, halogenated alkyl, halogenated alkenyl, halogenated alkenyloxy or halogenated alkoxy having up to 6 carbon atoms,

is -C2F4-, -CF=CF-, -C2H4-, -(CH₂)₄-, -OCH₂-, -CH₂0-, -CH=CH-, -CF₂0- or -OCF₂-, -C₂F₄-,

Y¹ to Y⁴ are each, independently of one another, H or F and r is 0 or 1 and

wherein further compounds of formula VII are excluded from formula VIII.

The compounds of the formula VI are preferably selected from the group of compounds of formulae VI-1 to VI-5, preferably of VI-1 and/or VI-2 and /or VI-4, most preferably of VI-2 and/or Vl-4,

wherein the parameters have the respective meanings given under formula VI above. The component B preferably additionally comprises one compound or more compounds with four six-membered rings selected from the group consisting of the general formulae IX to XVI:

in which R°, X° and Y¹ to Y⁴ have the respective meanings given under formulae IV to VIII and preferably

X° is F, Cl, CF_3l OCF₃ or OCHF₂ ,

R° is alkyl, oxaalkyl, fluoroalkyl or alkenyl, each having up to 6 carbon atoms.

The component B preferably additionally comprises one or more compounds selected from the group of ester compounds of formulae E-1 to E-4

in which R is as defined under formulae IV to Vlll.

The proportion of the compounds of the formulae E-1 to E-4 is preferably 10-30% by weight, in particular 15 % to 25 %.

The proportion of compounds of the formulae III to Vlll in the mixture as a whole is preferably from 1 % to 30 %.

is preferably — < 0 )^~ F,— < O )- F —< O

r r ό - OCF₃, ^~{θ OCF₃, -(c^- OCF₃, — (θ)- CF₃, F F F

-(0/-CF3, -(0 -CF3, -^®^^0CHF ₂.-Λ°y ^0CHF2_'

r I- t-

2 -0CHF₂, — (o^-CI, — (θ)-CI or - Cl.

The medium comprises compounds of the formulae II, III, IV, V, VI, VH and/or Vlll.

R° preferably is straight-chain alkyl or alkenyl having from 2 to 7 carbon atoms.

Component B preferably comprises further compounds, preferably selected from the following group consisting of the general formulae XVII to XXI:

X° XVIII

wherein R° and X° are as defined under formulae IV to VII and the 1 ,4-phenylene rings optionally may additionally be substituted by CN, Cl or Fluorine, preferably by F. The 1 ,4-phenylene rings are preferably monosubstituted or polysubstituted by F atoms.

The medium preferably additionally comprises one compound, two, three or more, preferably two or three, compounds selected from the group of compounds of the formulae 0-1 and 0-2

Alkyl- H H -CH₂0- H -Alkyl 0-1

wherein "Alkyl" and "Alkyl ' ", independently of each other, are as defined under formulae N-1 to N-6.

The proportion of the compounds of the formulae 0-1 and/or 0-2 in the mixtures according to the invention is preferably 5 % to 10 % by weight.

The medium preferably comprises one compound, two or three compounds of formula VII-4 in which X° is F or OCF₃.

The medium preferably comprises one compound or more compounds of the formulae 1V-1 to IV-7

wherein R has the meaning given under formula IV and preferably is methyl, ethyl, n-propyl, n-butyl, n-pentyl or vinyl.

The medium preferably comprises one compound or more compounds selected from the group of formulae Q-1 to Q-9

wherein R ι0 has the meaning given under formulae IV to Vlll.

The proportion of the compounds of the formula VI-1 and/or VI-12, in which X° preferably is fluorine, and R° preferably is CH₃, C₂H₅, n-C₃H7, n-C₄H9, n-CsHn or vinyl, in the mixture as a whole is from 2 % to 20 %, in particular from 2 % to 15 %.

The medium preferably comprises one compound or more compounds selected from the group of compounds of formulae II to VII in which R° is methyl.

The medium particularly preferably comprises one compound or more compounds selected from the group of compounds of formulae IV- 1a, IV-2a and Q-7a

The medium preferably comprises one dioxane compound, two or more dioxane compounds, preferably one dioxane compound or two dioxane compounds, selected from the group of formulae Dx-1 and Dx-2

The medium preferably additionally comprises one, two or more compounds with two cyclohexane rings selected from the group of formulae Z-1 to Z-6

wherein R° has the meaning given under formulae IV to Vlll, "Alkyl" and "Alkyl ' " have the respective meanings given under formulae 0-1 and 0-2 and

R^1a and R^2a are, each independently of each other, H, CH_3] C₂H₅ or n-C₃H₇,

The medium preferably comprises one, two or more compounds with two cyclohexane rings selected from the group of formulae Z-1 , Z-2, Z-5 and Z-6.

The medium preferably additionally comprises one, two or more compounds having fused rings, of the formulae AN-1 to AN-11

wherein R ι0 has the meaning given under formulae IV to Vlll.

It has been found that even a relatively small proportion of compounds of the formulae I mixed with conventional liquid-crystal materials, but in particular with one or more compounds of the formulae II, III, IV, V, VI VII and/or Vlll, results in a lower operating voltage and a broader operating temperature range. Preference is given, in particular, to mixtures which, besides one or more compounds of the formulae I, comprise one or more compounds of the formula II, in particular compounds of the formula II-5 and II-7 in which X² is F, Cl, CN, NCS, CF₃ or OCF₃. The compounds of the formulae I to Vlll are colourless, stable and readily miscible with one another and with other liquid-crystalline materials.

The optimum mixing ratio of the compounds of the formulae I and II + III + IV + V + VI + VII + Vlll depends substantially on the desired properties, on the choice of the components of the formulae I, II, III, IV, V, VI, VII and/or Vlll, and on the choice of any other components that may be present. Suitable mixing ratios within the range given above can easily be determined from case to case. The total amount of compounds of the formulae I to XXI in the mixtures according to the invention is not crucial. The mixtures can therefore comprise one or more further components for the purposes of optimisation of various properties. However, the observed effect on the operating voltage and the operating temperature range is generally greater, the higher the total concentration of compounds of the formulae I to XXI.

In a particularly preferred embodiment, the media according to the invention comprise compounds of the formulae 111 to Vlll in which X° is F, OCF₃, OCHF₂, OCH=CF₂, OCF=CF₂ or OCF₂-CF₂H. A favourable synergistic effect with the compounds of the formulae I results in particularly advantageous properties. In particular, mixtures comprising compounds of formula I and of formula II and of formula HI are distinguished by their low operating voltages.

The individual compounds of the formulae II to XXI and their respective sub-formulae which can be used in the media according to the invention are either known or can be prepared analogously to the known compounds.

The construction of the MLC display according to the invention from polarisers, electrode base plates and surface-treated electrodes corresponds to the conventional construction for displays of this type. The term conventional construction is broadly drawn here and also covers all derivatives and modifications of the MLC display, in particular including matrix display elements based on poly-Si TFT or MIM, however, particularly preferred are displays, which have electrodes on just one of the substrates, i.e. so called interdigital electrodes, as those used in IPS displays, preferably in one of the established structures.

A significant difference between the displays according to the invention and the conventional displays based on the twisted nematic cell consists, however, in the choice of the liquid-crystal parameters of the liquid-crystal layer. The media according to the invention are prepared in a manner conventional per se. In general, the components are dissolved in one another, advantageously at elevated temperature. By means of suitable additives, the liquid-crystalline phases in accordance with the invention can be modified in such a way that they can be used in all types of liquid crystal display elements that have been disclosed hitherto. Additives of this type are known to the person skilled in the art and are described in detail in the literature (H. Kelker and R. Hatz, Handbook of Liquid Crystals, Verlag Chemie, Weinheim, 1980). For example, pleochroic dyes can be added for the preparation of coloured guest-host systems or substances can be added in order to modify the dielectric anisotropy, the viscosity and/or the alignment of the nematic phases. Furthermore, stabilisers and antioxidants can be added.

The mixtures according to the invention are suitable for TN, STN, ECB and IPS applications and isotropic switching mode (ISM) applications. Hence, there use in an electro-optical device and an electro-optical device containing liquid crystal media comprising at least one compound according to the invention are subject matters of the present invention.

The inventive mixtures are highly suitable for devices which operate in an optically isotropic state. The mixtures of the invention are surprisingly found to be highly suitable for the respective use.

Electro-optical devices that are operated or operable in an optically isotropic state recently have become of interest with respect to video, TV, and multi-media applications. This is because conventional liquid crystal displays utilizing electro-optical effects based on the physical properties of liquid crystals exhibit a rather high switching time which is undesired for said applications. Furthermore most of the conventional displays show a significant viewing angle dependence of contrast that in turn makes necessary measures to compensate this undesired property.

With regard to devices utilizing electro-optical effects in an isotropic state the German Patent Application DE 102 17273 A1 for example discloses light controlling (light modulation) elements in which the mesogenic controlling medium for modulation is in the isotropic phase at the operating temperature. These light controlling elements have a very short switching time and a good viewing angle dependence of contrast. However, the driving or operating voltages of said elements are very often unsuitably high for some applications.

German Patent Application DE 10241 301 describes specific structures of electrodes allowing a significant reduction of the driving voltages. However, these electrodes make the process of manufacturing the light controlling elements more complicated.

Furthermore, the light controlling elements, for example, disclosed in both DE 102 17273 A1 and DE 10241 301 show a significant temperature dependence. The electro-optical effect that can be induced by the electrical field in the controlling medium being in an optical isotropic state is most pronounced at temperatures close to the clearing point of the controlling medium. In this range the light controlling elements have the lowest values of their characteristic voltages and, thus, require the lowest operating voltages. As temperature increases the characteristic voltages and hence the operating voltages increase remarkably. Typical values of the temperature dependence are in the range from about a few volts per centigrade up to about ten or more volts per centigrade. While DE 102 41 301 describes various structures of electrodes for devices operable or operated in the isotropic state, DE 102 17 273 A1 discloses isotropic media of varying composition that are useful in light controlling elements operable or operated in the isotropic state. The relative temperature dependence of the threshold voltage in these light controlling elements is at a temperature of 1 centigrade above the clearing point in the range of about 50%/centigrade. That temperature dependence decreases with increasing temperature so that it is at a temperature of 5 centigrade above the clearing point of about 10%/centigrade. However, for many practical applications of displays utilizing said light controlling elements the temperature dependence of the electro-optical effect is too high. To the contrary, for practical uses it is desired that the operating voltages are independent from the operating temperature over a temperature range of at least some centigrades, preferably of about 5 centigrades or more, even more preferably of about 10 centigrades or more and especially of about 20 centigrades or more.

Now it has been found that the use of the inventive mixtures are highly suitable as controlling media in the light controlling elements as described above and in DE 102 17 273 A1 , DE 10241 301 and DE 102 536 06 and broaden the temperature range in which the operating voltages of said electro-optical operates. In this case the optical isotropic state or the blue phase is almost completely or completely independent from the operating temperature.

This effect is even more distinct if the mesogenic controlling media exhibit at least one so-called "blue phase" as described in yet unpublished DE 103 13 979. Liquid crystals having an extremely high chiral twist may have one or more optically isotropic phases. If they have a respective cholesteric pitch, these phases might appear bluish in a cell having a sufficiently large cell gap. Those phases are therefore also called "blue phases" (Gray and Goodby, "Smectic Liquid Crystals, Textures and Structures", Leonhard Hill, USA, Canada (1984)). Effects of electrical fields on liquid crystals existing in a blue phase are described for instance in H.S. Kitzerow, "The Effect of Electric Fields on Blue Phases", Mol. Cryst. Liq. Cryst. (1991), Vol. 202, p. 51 -83, as well as the three types of blue phases identified so far, namely BP I, BP II, and BP III, that may be observed in field-free liquid crystals. It is noteworthy, that if the liquid crystal exhibiting a blue phase or blue phases is subjected to an electrical field, further blue phases or other phases different from the blue phases I, II and III might appear.

The inventive mixtures can be used in an electro-optical light controlling element which comprises

one or more, especially two substrates; an assembly of electrodes; one or more elements for polarizing the light; and - said controlling medium; whereby said light controlling element is operated (or operable) at a temperature at which the controlling medium is in an optically isotropic phase when it is in a non-driven state.

The controlling medium of the present invention has a characteristic temperature, preferably a clearing point, in the range from about -30 °C to about 80 °C, especially up to about 55 °C.

The operating temperature of the light controlling elements is preferably above the characteristic temperature of the controlling medium said temperature being usually the transition temperature of the controlling medium to the blue phase; generally the operating temperature is in the range of about 0.1 ° to about 50 °, preferably in the range of about 0.1 ° to about 10 ° above said characteristic temperature. It is highly preferred that the operating temperature is in the range from the transition temperature of the controlling medium to the blue phase up to the transition temperature of the controlling medium to the isotropic phase which is the clearing point. The light controlling elements, however, may also be operated at temperatures at which the controlling medium is in the isotropic phase.

(For the purposes of the present invention the term "characteristic temperature" is defined as follows:

If the characteristic voltage as a function of temperature has a minimum, the temperature at this minimum is denoted as characteristic temperature.

If the characteristic voltage as a function of temperature has no . minimum and if the controlling medium has one or more blue phases, the transition temperature to the blue phase is denoted as characteristic temperature; in case there are more than one blue phase, the lowest transition temperature to a blue phase is denoted as characteristic temperature.

- If the characteristic voltage as a function of temperature has no minimum and if the controlling medium has no blue phase, the transition temperature to the isotropic phase is denoted as characteristic temperature.)

In the context of the present invention the term "alkyl" means, as long as it is not defined in a different manner elsewhere in this description or in the claims, straight-chain and branched hydrocarbon (aliphatic) radicals with 1 to 15 carbon atoms. The hydrocarbon radicals may be unsubstituted or substituted with one or more substituents being independently selected from the group consisting of F, Cl, Br, I or CN.

The dielectrics may also comprise further additives known to the person skilled in the art and described in the literature. For example, 0 to 5% of pleochroic dyes, antioxidants or stabilizers can be added.

C denotes a crystalline phase, S a smectic phase, S_c a smectic C phase, N a nematic phase, I the isotropic phase and BP the blue phase.

V_x denotes the voltage for X% transmission. Thus e.g. V₁₀ denotes the voltage for 10% transmission and V₁₀₀ denotes the voltage for 100% transmission (viewing angle perpendicular to the plate surface). t_oπ

(respectively τ_on) denotes the switch-on time and t_off (respectively τ_0{f) the switch-off time at an operating voltage corresponding the value of V₁₀₀, respectively of V_max.

Δn denotes the optical anisotropy. Δε denotes the dielectric anisotropy (Δε = ε,_| - ε_L, where ε_(l denotes the dielectric constant parallel to the longitudinal molecular axes and ε_λ denotes the dielectric constant perpendicular thereto). The electro-optical data are measured in a TN cell at the 1 ^st minimum of transmission (i.e. at a (d • Δn) value of 0.5 μm) at 20°C, unless expressly stated otherwise. The optical data are measured at 20°C, unless expressly stated otherwise.

Optionally, the light modulation media according to the present invention can comprise further liquid crystal compounds in order to adjust the physical properties. Such compounds are known to the expert. Their concentration in the media according to the instant invention is preferably 0 % to 30 %, more preferably 0 % to 20 % and most preferably 5 % to15 %.

Preferably the inventive media have a range of the blue phase or, in case of the occurrence of more than one blue phase, a combined range of the blue phases, with a width of 9° or more, preferably of 10° or more, more preferably of 15° or more and most preferably of 20° or more. This range may include biphasic systems in which two phases are coexisting with each other.

In a preferred embodiment this phase range at least from 10°C to 30°C, most preferably at least from 10°C to 40°C and most preferably at least from 0°C to 50°C, wherein at least means, that preferably the phase extends to temperatures below the lower limit and at the same time, that it extends to temperatures above the upper limit.

In another preferred embodiment this phase range at least from 20°C to 40°C, most preferably at least from 30°C to 80°C and most preferably at least from 30°C to 90°C. This embodiment is particularly suited for displays with a strong back light, dissipating energy and thus heating the display.

In the present application the term dielectrically positive compounds describes compounds with Δε > 1 ,5, dielectrically neutral compounds are compounds with -1 ,5 < Δε < 1 ,5 and dielectrically negative compounds are compounds with Δε < -1 ,5. The same holds for components. Δε is determined at 1 kHz and 20 °C. The dielectrical anisotropies of the compounds is determined from the results of a solution of 10 % of the individual compounds in a nematic host mixture. The capacities of these test mixtures are determined both in a cell with homeotropic and with homogeneous alignment. The cell gap of both types of cells is approximately 20 μm. The voltage applied is a rectangular wave with a frequency of 1 kHz and a root mean square value typically of 0.5 V to 1.0 V, however, it is always selected to be below the capacitive threshold of the respective test mixture and thus may be as small as 0.1 V. For dielectrically positive compounds the mixture ZLI-4792 and for dielectrically neutral, as well as for dielectrically negative compounds, the mixture ZLI-3086, both of Merck KGaA, Germany are used as host mixture, respectively. The dielectric permittivities of the compounds are determined from the change of the respective values of the host mixture upon addition of the compounds of interest and are extrapolated to a concentration of the compounds of interest of 100 %.

Components having a nematic phase at the measurement temperature of 20 °C are measured as such, all others are treated like compounds.

The term threshold voltage refers in the instant application to the optical threshold and is given for 10 % relative contrast (Vι₀) and the term saturation voltage refers to the optical saturation and is given for 90 % relative contrast (V_go) both, if not explicitly stated otherwise. The capacitive threshold voltage (V₀, also called Freedericksz-threshold V_Fr) is only used if explicitly mentioned.

The ranges of parameters given in this application are all including the limiting values, unless explicitly stated otherwise.

Throughout this application, unless explicitly stated otherwise, all concentrations are given in mass percent and relate to the respective complete mixture, all temperatures are given in degrees centigrade (Celsius) and all differences of temperatures in degrees centigrade. All physical properties have been and are determined according to "Merck Liquid Crystals, Physical Properties of Liquid Crystals", Status Nov. 1997, Merck KGaA, Germany and are given for a temperature of 20 °C, unless explicitly stated otherwise. The optical anisotropy (Δn) is determined at a wavelength of 589.3 nm. The dielectric anisotropy (Δε) is determined at a frequency of 1 kHz. The threshold voltages, as well as all other electro- optical properties have been determined with test cells prepared at Merck KGaA, Germany. The test cells for the determination of Δε had a cell gap of 22 μ . The electrode was a circular ITO electrode with an area of 1.13 cm² and a guard ring. The orientation layers were lecithin for homeotropic orientation (ε| |) and polyimide AL-1054 from Japan Synthetic Rubber for homogenous orientation (εi). The capacities were determined with a frequency response analyser Solatron 1260 using a sine wave with a voltage of 0.3 or 0.1 \/_ms. The light used in the electro-optical measurements was white light. The set up used was a commercially available equipment of Otsuka, Japan. The characteristic voltages have been determined under perpendicular observation. The threshold voltage (V₁₀), mid-grey voltage (V₅₀) and saturation voltage (V₉₀) have been determined for 10 %, 50 % and 90 % relative contrast, respectively.

The mesogenic modulation material has been filled into an electro optical test cell prepared at the respective facility of Merck KGaA. The test cells had inter-digital electrodes on one substrate side. The electrode width was 10 μm, the distance between adjacent electrodes was 10 μm and the cell gap was also 10 μm. This test cell has been evaluated electro-optically between crossed polarisers.

At low temperatures, the filled cells showed the typical texture of a chiral nematic mixture, with an optical transmission between crossed polarisers without applied voltage. Upon heating, at a first temperature (T-i) the mixtures turned optically isotropic, being dark between the crossed polarisers. This indicated the transition from the chiral nematic phase to the blue phase at that temperature. Up to a second temperature (T₂) the cell showed an electro-optical effect under applied voltage, typically of some tens of volts, a certain voltage in that range leading to a maximum of the optical transmission. Typically at a higher temperature the voltage needed for a visible electro-optical effect increased strongly, indicating the transition from the blue phase or from a biphasic sytem to the isotropic phase at this second temperature (T₂).

The temperature range (ΔT(BP)), where the mixture can be used electro- optically in the blue phase most beneficially has been identified as ranging from T to T₂. This temperature range (ΔT(BP)) is the temperature range given in the examples of this application. The electro-optical displays can also be operated at temperatures beyond this range, i.e. at temperatures above T₂, albeit only at significantly increased operation voltages. The liquid crystal media according to the present invention can contain further additives and chiral dopants in usual concentrations. The total concentration of these further constituents is in the range of 0 % to 10 %, preferably 0.1 % to 6 %, based on the total mixture. The concentrations of the individual compounds used each are preferably in the range of 0.1 to 3 %. The concentration of these and of similar additives is not taken into consideration for the values and ranges of the concentrations of the liquid crystal components and compounds of the liquid crystal media in this application.

The inventive liquid crystal media according to the present invention consist of several compounds, preferably of 3 to 30, more preferably of 5 to 20 and most preferably of 6 to 14 compounds. These compounds are mixed in conventional way. As a rule, the required amount of the compound used in the smaller amount is dissolved in the compound used in the greater amount. In case the temperature is above the clearing point of the compound used in the higher concentration, it is particularly easy to observe completion of the process of dissolution. It is, however, also possible to prepare the media by other conventional ways, e. g. using so called pre-mixtures, which can be e. g. homologous or eutectic mixtures of compounds or using so called multi-bottle-systems, the constituents of which are ready to use mixtures themselves.

By addition of suitable additives, the liquid crystal media according to the instant invention can be modified in such a way, that they are usable in all known types of liquid crystal displays, either using the liquid crystal media as such, like TN-, TN-AMD, ECB-, VAN-AMD and in particular in composite systems, like PDLD-, NCAP- and PN-LCDs and especially in HPDLCs.

The melting point T(C,N), the transition from the smectic (S) to the nematic (N) phase T(S,N) and the clearing point T (N,l) of the liquid crystals are given in degrees centigrade.

In the present application and especially in the following examples, the structures of the liquid crystal compounds are represented by abbreviations also called acronyms. The transformation of the abbreviations into the corresponding structures is straight forward according to the following two tables A and B. All groups C_nH_2n+1 and C_mH_2m+1 are straight chain alkyl groups with n respectively m D-atoms. The interpretation of table B is self evident. Table A does only list the abbreviations for the cores of the structures. The individual compounds are denoted by the abbreviation of the core followed by a hyphen and a code specifying the substituents Ri, R2, Li and L≥ follows:

nm C_nH_2n+ι C H₂m₊ι H H nOm C_nH_2n+ι OC_mH_2m+ι H H nO.m OC_nH_2n+ι C_mH_2m+ι H H n C_nH_2n+ι CN H H nN.F O_nH_2n+ι CN H F nN.F.F C_nH_2n+ι CN F F nF C_nH_2n+ι F H H nF.F C_nH _n+ι F H F nF.F.F C_nH_2n+-| F F F nOF OC_nH_2n+1 F H H nCI C_nH_2n+ι Cl H H nCI.F C_nH_2n+ι Cl H F nCI.F.F C_nH_2n+ι Cl F F nCF₃ O_nH _n+ι CF₃ H H nOCF₃ C_nH _π+ι OCF₃ H H nOCF₃.F C_nH_2n+ι OCF₃ H F nOCF₃.F.F C_nH_2n+ι OCF₃ F F nOCF₂ C_nH_2π+ι OCHF₂ H H nOCF₂.F CnH_2n+ι OCHF₂ H F nOCF₂.F.F C_nH_2n+ι OCHF₂ F F nS C_nH_2n+ι NCS H H nS.F C_nH_2n+ι NCS H F nS.F.F 0_nH_2n+ι NCS F F rVsN C_rH_2r+-)-CH=CH-C₃H _s- CN H H rEsN C_rH_2r+ -0-C₃H_2s- CN H H nAm O_nH_2n+ι COOC_mH_2m+1 H H nF.CI C_nH_2n+ι Cl H F

PCH EPCH

BCH CCP

CECP ECCP

BECH EBCH

PTP CPTP

CEPTP

CCH PDX

YP PYRP

D ME

HP CP

EHP

ET

FET

Table B:

(X=F, CF3, OCHF2or 0CF3)

CB15 C15

CBC-nm

CBC-nmF

K3n M3n

PG-n-AN

PU-n-AN

PPYRP-nN

PPYP-nN

PGP-n-N

PGIP-n-N

PVG-n-S

PVG-nO-S

PVG-V-S

PVG-nV-S

PVG-Vn-S

PPVU-n-S

CPVP-n-N

PTP-n(0)-S

PTG-n(0)-S

PTU-n(0)-S

PTPG-n(0)-N

GGP-n-CL

PGIGI-n-CL

CGU-n-F

PPU-n-S

PGU-n-S

BB3n

C„

nH 2n+1 ° A o ⁽-^/m''2m+1

PPTUI-n-m

F CH ',2_nn_ι+₁1-< 0 V-COO— < O )— CN

GZU-n-N

^Cn^H2n₊r^~0_ ° )—^C00 ° ^~"CN

GZU-nO-N

GZU-nA-N

UZU-n-N

UZU-nO-N

UZU-nA-N

CUZU-n-N

CGP-n-m

CFU-n-F

CBC-nm

CBC-nmF

c_nH_2n+1 Λ ^HV ^C ° ^C-^H—

ECCP-nm

CCZU-n-F

T-nFm

CGG-n-F

CGU-n-F

CDU-n-F

°_" ^H--C $-^F F

DCU-n-F

CPZG-n-OT

CCP-Vn-m

CCG-V-F

CCP-nV-m

CC-n-V

CC-n-V1

CC-nV-Vm

CCQU-n-F

F

CQCU-n-F

Dec-U-n-F

CWCG-n-F

CWCU-n-F

CCOC-n-m

CPTU-n-F

C_nH_M

GPTU-n-F

PQU-n-F

PUQU-n-F

PUQU-n-S

PUQU-n-OT

PUQU-n-T

PUZU-n-F

PGU-n-F

AUZU-n-F

AUZU-n-N

CGZP-n-OT

CCGU-n-F

CCQG-n-F

CUQU-n-F

CCCQU-n-F

AGUQU-n-F

AUUQU-n-F

AUUQU-n-N

CUUQU-n-F

CUUQU-n-OT

GZU-nA-N 05/105952

-95-

UZU-nA-N

AUUQU-n-OT

AUUQU-n-T

AUUQP-n-T

AUUQGU-n-F

AUUQPU-n-F

CUZP-nN.F.F

GZU-nO-N

Particular preference is given to liquid-crystalline mixtures which, besides the compounds of the formula I, comprise at least one, two, three or four compounds from Table B.

Table C:

Table C shows possible dopants according to component D which are generally added to the mixtures alone or in combination two, three or more) according to the invention.

C 15

CB 15

CM 21

R/S-811

CM 44

CM45

CM 47

R/S-1011

RS-3011

R/S-2011

R/S-4011

R/S-5011 Table D

Stabilisers which can be added, for example, to the mixtures according to the invention are mentioned below.

H₃₇C₁₈-COO-C_{2 8}HH₄„— — ( { ό O -θOH

35

20

The liquid crystal media according to the instant invention do contain preferably

- four or more compounds selected from the group of compounds of tables A and B and/or

- five or more compounds selected from the group of compounds of table B and/or

- two or more compounds selected from the group of compounds of table A.

Examoles

/

The examples given in the following are illustrating the present invention without limiting it in any way.

However, the physical data especially of the compounds illustrate to the expert which properties can be achieved in which ranges. Especially the combination of the various properties which can be preferably achieved is thus well defined.

Example 1

Preparation of

The compound (3) is prepared according to the following reaction scheme:

2

A mixture of 3 g of (1), 10.5 g of (2), 233 mg PdCI₂(dppf), 34 ml dioxane and 12.6 ml 2 molar aquous solution of Na₂C0₃ is heated under reflux for 18 h. The product is purified according to standard procedures. The crude product is purified over silicagel with a solvent mixture of heptane and CH₂CI₂ in the mixing ratio of 1 :1 and subsequently and re-crystallized from toluene. The yield is 3.8 g of (3), i.e. 47% of the theoretical yield.

The product has a phase sequence of T_g 15°C C 154°C

Example 2

Analogously to example 1 the following compound is prepared:

The product has a phase sequence of C 55°C I. Example 3

Analogously to example 1 the following compound is prepared:

The product has a phase sequence of T_g 18°C C 145°C I.

Example 4 Analogously to example 1 the following compound is prepared:

The product has a phase sequence of T_g 15°C C 148°C I. Example 5

Analogously to example 1 the following compound is prepared:

The product has a phase sequence of C 172°C Example 6

Analogously to example 1 the following compound is prepared:

The product has a phase sequence of T_g 23°C C 105°C I. Examples 7 to 58

Analogously to example 1 the following compounds are prepared:

No. R 11 11' 12 12' Phases (T/°C)

7 H H H H H

8 CH₃ H H H H

9 C₂H_δ H H H H

10 n-C₃H₇ H H H H

11 π-C₄H₉ H H H H

12 A7-C₅Hn H H H H

15 π-C₈H₁₇ H H H H

17 n-CιoH₂ι H H H H

18 CH₂=CH H H H H

19 CH₂=CH-CH₂ H H H H 2200 H F H F H 2211 CH₃ F H F H 2222 C₂H_δ F H F H 2233 π-C₃H₇ F H F H

24 n-C₄H₉ F H F H

25 / C₅Hn F H F H

27 n-C₇H₁₅ F H F H

28 n-C₈Hι₇ F H F H

No. R L¹¹ L^11' L¹² L^12' Phases (T/°C)

30 π-CιoH₂ι F H F H

31 CH₂=CH F H F H

32 CH₂=CH-CH₂ F H F H

33 H H F H F

34 CH₃ H F H F

35 C₂H_δ H F H F

36 n-C₃H₇ H F H F

37 /7-C₄H₉ H F H F

38 π-C₅Hn H F H F

39 n-CeHι₃ H F H F

40 /7-C₇His H F H F

41 π-C₈H₁₇ H F H F

42 π-CgHιg H F H F

43 π-CιoH₂ι H F H F

44 CH₂=CH H F H F

45 CH =CH-CH₂ H F H F

46 H F F F F

47 CH₃ F F F F

48 C₂H_δ F F F F

49 n-C₃H₇ F F F F

50 t7-C₄Hg F F F F

51 n-CsHn F F F F

53 /7-C₇H₁₅ F F F F

54 n-C₈H₁₇ F F F F

57 CH₂=CH F F F F

58 CH₂=CH-CH₂ F F F F

Examples 59 to 120

Analogously to example 1 the following compounds are prepared:

LO O LO O LO

LO CM CM CO CO

No. R L¹¹ L^11' L¹² L^12' Phases (T/°C)

95 H H F H F

96 CH₃ H F H F

97 C₂H_δ H F H F

98 /7-C₃H₇ H F H F

100 π-C₅Hιι H F H F

102 /7-C₇H₁₅ H F H F

104 /7-CgHιg H F H F

105 /7-CιoH₂ι H F H F

106 CH₂=CH H F H F

107 CH₂=CH-CH₂ H F H F

108 H F F F F

109 CH₃ F F F F

1 10 C₂H_δ F F F F

1 1 1 A7-C₃H₇ F F F F

1 13 A7-C₅Hn F F F F

1 16 π-C₈H₁₇ F F F F

1 17 n-CgHig F F F F

1 18 7-CιoH₂ι F F F F

1 19 CH₂=CH F F F F

120 CH₂=CH-CH₂ F F F F

Examples 121 to 171

Analogously to example 1 the following compounds are prepared:

LO o LO O LO

LO CM CM CO CO

No. R L¹¹ L^11' L¹² L^12' Phases (T/°C)

145 CH₂=CH F H F H

146 CH₂=CH-CH₂ F H F H

147 H H F H F

148 CH₃ H F H F

150 n-C₃H₇ H F H F

152 /7-C₅Hn H F H F

155 n-C_ar]₁₇ H F H F

156 π-CgHig H F H F

157 π-C-ιoH₂ι H F H F

158 CH₂=CH H F H F

159 CH =CH-CH₂ H F H F

160 H F F F F

161 CH₃ F F F F

162 C₂H_δ F F F F

6 π-C₃H₇ F F F F T_g 23 C 105 l

164 t7-C₅Hn F F F F

165 π-CeHι₃ F F F F

166 π-C₇H₁₅ F F F F

167 /7-C₈H₁₇ F F F F

168 /1-CgHιg F F F F

169 n-CιoH₂ι F F F F

170 CH₂=CH F F F F

171 CH₂=CH-CH₂ F F F F

Examples 172 to 229

Analogously to example 1 the following compounds are prepared:

No. R R' L¹¹ L^11' L¹² L^12' Phases (T/°C)

172 CH₃ CH₃ H H H H

173 C₂H_δ CH₃ H. H H H

174 n-C₃H₇ CH₃ H H H H

176 π-CsHu CH₃ H H H H

178 n-C₇H₁₅ CH₃ H H H H

179 7-C₈H₁₇ CH₃ H H H H

181 A7-CιoH₂ι CH₃ H H H H

182 CH₂=CH CH₃ H H H H

183 CH₂=CH-CH₂ CH₃ H H H H

184 C₂Hs C₂H₅ H H H H

185 /7-C3H7 /7-C3H7 H H H H

186 π-C₄H₉ π-C₄H₉ H H H H

187 n-C₅Hn n-C5H.11 H H H H

189 n-C₇H₁₅ π-C₇H₉ H H H H

190 π-C₈H₁₇ n-C₈Hι₇ H H H H

191 /?-CgHi₉ A7-CgH g H H H H

192 π-CιoH₂ι r/-C oH₂ι H H H H

193 CH₂=CH CH₂=CH H H H H

195 CH₃ CH₃ F H F H

196 C₂H_δ C₂H₅ F H F H

197 />C₃H₇ π-C₃H₇ F H F H No. R R' L¹¹ L^11' L¹² L^12' Phases (T/°C)

199 /7-C5H11 π-C₅Hn F H F H

200 n-C₈Hi₃ r-C₈Hi₃ F H F H

201 /7-C₇Hi5 n-C₇H₉ F H F H

202 /7-C₈H₁₇ t?-C₈H₁₇ F H F H

203 A7-CgHιg n-C Hig F H F H

204 π-C oH₂ι n-CιoH₂ι F H F H

205 CH₂=CH CH₂=CH F H F H

206 CH₂=CH-CH₂ CH₂=CH-CH₂ F H F H

207 CH₃ CH₃ H ^' F H F

208 C₂Hs C₂H_δ H F H F

21 1 n-Cs 7-C5H1₁ H F H F

212 -C₈Hi₃ r/-CβHi₃ H F H F

213 A7-C7H15 n-C₇Hg H F H F

214 A?-C₈Hi7 π-C₈Hi7 H F H F

215 /7-CgHιg /7-CgHig H F H F

216 n-CιoH₂ι /7-C10H21 H F H F

217 CH₂=CH CH₂ ⁼CH H F H F

219 CH₃ CH₃ F F F F

223 π-C₅Hn n-C₅Hn F F F F

5 Ϊ-C₈HI7 n-C₈Hi₇ F F F F C 172 I

226 /7-CgHig /7-CgHig F F F F

227 n-CιoH₂ι n-CιoH₂ F F F F

228 CH₂=CH CH₂=CH F F F . F

229 CH₂=CH-CH CH₂=CH-CH F F F F Examples 230 to 280

Analogously to example 1 the following compounds are prepared:

No. R 11 _Lii- _Lia _L12- p_hasθS (_T/°c)

230 H H H H H

231 CH₃ H H H H

233 n-C₃H₇ H H H H

234 n-C₄H₉ H H H H

238 A7-C₈Hi₇ H H H H

239 /7-CgHig H H H H

240 r⁾-CιoH₂ι H H H H

241 CH₂=CH H H H H

243 H F H F H

244 CH₃ F H F H

246 n-C₃H₇ F H F H

247 n-C₄H_g F H F H

248 π-C₅Hn F H F H

- 1 17 -

No. R L¹¹ L^11' L¹² _L12- Phases (T/°C)

252 n-CgHi F H F H

253 r?-CιoH₂ι F H F H

254 CH₂=CH F H F H

255 CH₂=CH-CH₂ F H F H

256 H H F H F

257 CH₃ H F H F

260 π-C₄H₉ H F H F

264 A7-C₈H₁₇ H F H F

267 CH₂=CH H F H F

268 CH₂=CH-CH H F H F

1 H F F F F T_g 15 C 154 l

269 CH₃ F F F F

270 C₂H_δ F F F F

272 π-C₄H₉ F F F F

273 n-C₆Hn F F F F

275 7-C₇H₁₅ F F F F

276 /7-C₈H₁₇ F F F F

277 /7-CgHig F F F F

279 CH₂=CH F F F F

280 CH2⁼CH-CH₂ F F F F

Examples 281 to 280 Analogously to example 1 the following compounds are prepared:

No. R 11 11' 12 12' Phases (T/°C)

281 H H H H H

282 CH₃ H H H H

283 C₂H_δ H H H H

284 /7-C₃H₇ H H H H

285 π-C₄H₉ H H H H

286 n-C₅Hn H H H H

288 n-C₇H₁₅ H H H H

290 t7-CgHιg H H H H

291 n-CιoH₂ι H H H H

292 CH₂=CH H H H H

293 CH₂=CH-CH H H H H

294 H F H F H

295 CH₃ F H F H

296 C₂H₅ F H F H

297 π-C₃H₇ F H F H

298 π-C₄H₉ F H F H

299 n-CsHn F H F H

301 n-C₇H₁₅ F H F H No. R L.11 L^11' L¹² L¹²' Phases (T/°C)

305 CH₂=CH F H F H

306 CH₂=CH-CH₂ F H F H

307 H H F H F

308 CH₃ H F H F

309 C₂H₅ H F H F

311 n-C₄H₉ H F H F

312 n-C₅Hn H F H F

313 /7-C₆H₁₃ H F H F

314 n-C₇H₁₅ H F H F 315 π-C₈Hι₇ H F H F

317 n-C₁₀H₂₁ H F H F

318 CH₂=CH H F H F

319 CH₂=CH-CH₂ H F H F 320 H F F F F

321 CH₃ F F F F

322 C₂H₅ F F F F

323 π-C₃H₇ F F F F

324 n-C₄H₉ F F F F 325 π-C₅Hιι F F F F

326 π-C₆Hι₃ F F F F

330 n-CιoH₂ι F F F F

331 CH₂=CH F F F F

332 CH₂=CH-CH₂ F F F F

Examples 333 to 384

Analogously to example 1 the following compounds are prepared:

LO o LO o LO

LO CM CM CO CO

No. R L¹¹ L^{1 '} L¹² L^12' Phases (T/°C)

357 CH₂=CH F H F H

358 CH₂=CH-CH₂ F H F H

359 H H F H F

360 CH₃ H F H F

362 n-C₃H₇ H F H F

366 7-C₇H₁₅ H F H F

368 D-CgHig H F H F

370 CH₂=CH H F H F

371 CH₂=CH-CH₂ H F H F

372 H F F F F

373 CH₃ F F F F

374 C₂H_δ F F F F

375 n-C₃H₇ F F F F

376 π-C₄H₉ F F F F

377 n-C₅Hιι F F F F

381 /7-CgHig F F F F

383 CH₂=CH F F F F

Examples 385 to 436

Analogously to example 1 the following compounds are prepared:

No. R 11 11' 12 12' Phases (T/°C)

385 H H H H H 386 CH₃ H H H H 387 C₂H_δ H H H H 388 n-C₃H₇ H H H H 389 n-C₄H₉ H H H H

391 t7-CeHι₃ H H H H

393 n-C₈H_i7 H H H H 394 /7-CgHig H H H H 395 n-CιoH₂ι H H H H 396 CH₂=CH H H H H 397 CH₂=CH-CH₂ H H H H 398 H F H F H 399 CH₃ F H F H 400 C₂H_δ F H F H 401 n-C₃H₇ F H F H 402 π-C₄H₉ F H F H 403 ?-C₅Hιι F H F H

405 n-C₇H₁₅ F H F H

407 t7-CgHig F H F H No. R L¹¹ L^11' L¹² L^12' Phases (T/°C)

408 π-QιoH₂ι F H F H

409 CH₂=CH F H F H

410 CH₂ ⁼CH-CH₂ F H F H

411 H H F H F

413 C₂H_δ H F H F

414 π-C₃H₇ H F H F

415 /7-C₄Hg H F H F

419 /7-C₈Hi7 H F H F

420 /7-CgHig H F H F

421 n-CιoH₂ H F H F

422 CH₂=CH H F H F

423 CH₂=CH-CH₂ H F H F

424 H F F F F

425 CH₃ F F F F

427 π-C₃H₇ F F F F

429 π-C₅Hn F F F F

433 7-CgHig F F F F

435 CH₂=CH F F F F

Examples 437 to 487

Analogously to example 1 the following compounds are prepared:

No. R 11 ιr 12 , 12'

LA LA Phases (T/°C)

437 H H H H H

438 CH₃ H H H H

439 C₂H_δ H H H H

440 n-C₃H₇ H H H H

441 /7-C Hg H H H H

444 π-C₇H₁₅ H H H H

446 /7-CgHig H H H H

447 π-CιoH₂ι H H H H

448 CH₂=CH H H H H

449 CH₂=CH-CH₂ H H H H

450 H F H F H

451 CH₃ F H F H

453 π-C₃H₇ F H F H

454 n-C₄H F H F H

No. R L¹¹ L^11' L¹² L^12' Phases (T/°C)

458 A7-C₈H₁₇ F H F H

459 n-CgHig F H F H

461 CH₂=CH F H F H

462 CH₂=CH-CH₂ F H F H

463 H H F H F

464 CH₃ H F H F

465 C₂H_δ H F H F

466 n-C₃H₇ H F H F

468 /7-C₅Hn H F H F

470 π-C₇H₁₅ H F H F

472 /7-CgHig H F H F

473 r-CιoH₂ι H F H F

474 CH₂=CH H F H F

476 H F F F F

477 CH₃ F F F F

3 n-C₃H₇ F F F F T_g 18 C 145 l

480 π-C₅Hn F F F F

481 /7-C₈Hι₃ F F F F

483 π-C₈Hι₇ F F F F

484 7-CgHig F F F F

486 CH₂=CH F F F F

Examples 488 to 539

Analogously to example 1 the following compounds are prepared:

No. R L¹¹ L^11' L¹² L^12' Phases (T/°C)

488 H H H H H

489 CH₃ H H H H

492 π-C₄H₉ H H H H

493 π-C₅Hιι H H H H

499 CH₂=CH H H H H

501 H F H F H

502 CH₃ F H F H

504 t7-C₃H₇ F H F H

505 π-C₄H₉ F H F H

506 A7-C₅Hιι F H F H

No. R L¹¹ L^11' L¹² _L12' Phases (T/°C)

510 A7-CgHιg F H F H

511 π-CιoH₂ι F H F H

512 CH₂=CH F H F H

513 CH₂=CH-CH₂ F H F H

514 H H F H F

515 CH₃ H F H F

516 C₂H₅ H F H F

517 n-C₃H₇ H F H F

518 n-C₄H₉ H F H F

519 /7-C₅H₁₁ H F H F

522 f?-C₈Hi₇ H F H F

523 n-CgH H F H F

524 n-CιoH₂ι H F H F

525 CH₂=CH H F H F

526 CH₂=CH-CH₂ H F H F

527 H F F F F ,

528 CH₃ F F F F

529 C₂H_δ F F F F

530 n-C₃H₇ F F F F

531 n-C₄H₉ F F F F

532 π-C₅Hιι F F F F

534 r?-C₇Hι₅ F F F F

536 /7-CgHig F F F F

537 π-CιoH₂ι F F F F

538 CH₂=CH F F F F

539 CH₂=CH-CH₂ F F F F

Examples 540 to 598 Analogously to example 1 the following compounds are prepared:

No. R R L¹¹ L¹¹' L¹² L¹²' Phases (T/°C)

540 CH₃ CH₃ H H H H

542 n-C₃H₇ CH₃ H H H H

543 n-C₄H₉ CH₃ H H H H

544 Λ-CsHn CH₃ H H H H

546 n-C₇H₁₅ CH₃ H H H H

547 /7-C₈H₁₇ CH₃ H H H H

548 1-CgH g CH₃ H H H H

549 n-CιoH₂ι CH₃ H H H H

550 CH₂=CH CH₃ H H H H

551 CH₂=CH-CH₂ CH₃ H H H H

553 /7-C3H7 /7-C₃H₇ H H H H

555 π-C₅Hn π-CsHu H H H H

556 π-C₈Hi₃ n-C₆Hι₃ H H H H

557 /7-C₇H₁₅ 7-C₇Hg H H H H

558 n-C₈Hi₇ n-C₈H ₇ H H H H

559 n-CgHιg n-CgH g H H H H

560 A7-CιoH₂ι A?-C oH₂ι H H H H No. R R L¹¹ L^11' L¹² L¹²' Phases (T/°C)

561 CH₂=CH CH₂=CH H H H H

563 CH₃ CH₃ F H F H

564 C₂H₅ C₂H_δ F H F H

565 π-C₃H₇ n-C₃H₇ F H F H

566 π-C₄H₉ n-C₄H₉ F H F H

567 /7-C5H₁1 t?-C₅H ι F H F H

568 π-CeHi₃ n-CβHi₃ F H F H

570 n-C_{a 17} /7-C₈Hi7 F H F H

571 f7-CgHιg D-CgHig F H F H

572 n-CιoH₂ι π-CιoH₂ F H F H

573 CH₂=CH CH₂=CH F H F H

574 CH₂=CH-CH₂ CH₂=CH-CH₂ F H F H

575 CH₃ CH₃ H F H F

577 n-C₃H₇ π-C₃H₇ H F H F

579 7-C₅Hn π-CsHu H F H F

580 π-CβHi₃ π-CβH ₃ H F H F

582 /7-C₈H₁₇ n-C₈H 7 H F H F

583 A7-CgHιg t?-CgHig H F H F

584 H-CιoH2l π-CιoH₂ H F H F

585 CH₂=CH CH₂=CH H F H F

586 CH₂=CH-CH₂ CH₂=CH-CH₂ H F H F

587 CH₃ CH₃ F F F F

589 7-C3H7 r?-C₃H₇ F . F F F

594 n-C₈Hι₇ π-C₈Hi7 F F F F No. R R 11 L^11' L¹² _L12'

Phases (T/°C)

595 r?-CgH₁₉ /7-CgHig F F F F

596 π-CιoH₂ι π-CιoH₂ι F F F F

597 CH₂=CH CH₂=CH F F F F

598 CH₂=CH-CH₂ CH₂=CH-CH₂ F F F F

Examples 599 to 657

Analogously to example 1 the following compounds are prepared:

No. R R 11 11' L¹² L^12' Phases

(T/°C)

599 CH₃ CH₃ H H H H

600 C₂H_δ CH₃ H H H H

601 r?-C₃H₇ CH₃ H H H H

603 /?-C₅Hn CH₃ H H H H

604 t7-C₈Hi₃ CH₃ H H H H

606 / C_aHι₇ CH₃ H H H H

607 n-CgHig CH₃ H H H H

608 n-CιoH₂ι CH₃ H H H H

609 CH₂=CH CH₃ H H H H

>

No. R R L¹¹ L¹¹' L¹² L¹²' Phases (T/°C)

612 π-C₃H₇ π-C₃H₇ H H H H

613 7-C₄Hg t7-C Hg H H H H

614 n-C₅Hn π-C₅Hιι H H H H

615 π-CeH ₃ n-CβHι₃ H H H H

616 7-C₇H₁₅ /7-C₇Hg H H H H

617 π-C₈H₁₇ n-C₈H₁₇ H H H H

618 /J-CgH g /7-C₉H₁₉ H H H H

619 /7-C10H21 -C10H21 H H H H

620 CH₂=CH CH₂=CH H H H H

622 CH₃ CH₃ F H F H

623 C₂H₅ C₂H_δ F H F H

624 n-C₃H₇ n-C₃H₇ F H F H

625 n-C₄H₉ n-C₄H₉ F H F H

626 π-CsHu 7-C5H11 F H F H

627 π-C₈Hi₃ n-CβHi3 F H F H

629 A7-C₈H ₇ r?-C₈Hι₇ F H F H

630 n-CgH g n-C Hig F H F H

631 / -C10H21 π-C oH₂ι F H F H

632 CH₂=CH CH₂=CH F H F H

634 CH₃ CH₃ H F H F

636 n-C₃H₇ n-C₃H₇ H F H F

637 n-C₄H₉ n-C₄H₉ H F H F

638 n-C₅Hn /7-C₅Hn H F H F

639 rt-C₈H ₃ π-CβHi3 H F H F

641 π-C₈Hi₇ π-C₈Hι H F H F

642 /7-CgHig /7-CgHig H F H F

643 π-CιoH2i π-CιoH2i H F H F

644 CH₂=CH CH₂=CH H F H F No. R R 11 11' 12 12'

Phases (T/°C)

646 CH₃ CH₃ F F F F

647 C₂H_δ C₂H_δ F F F F

648 π-C₃H₇ π-C₃H₇ F F F F

649 n-C₄H₉ π-C₄H₉ F F F F

651 π-CeHi₃ /7-CgHi₃ F F F F

652 n-C₇H₁₅ n-C₇H₉ F F F F

654 /7-CgHig 7-CgHig F F F F

655 n-CιoH₂ι n-CιoH₂ι F F F F

656 CH₂=CH CH₂=CH F F F F

Examples 656 to 799

Analogously to example 1 the following compounds are prepared:

No. R R R"¹ L¹¹ L^11' Phases (T/°C)

656 CH₃ CH₃ H H H

657 C H₅ CH₃ H H H

No. R R R"¹ L ^{1 11}' Phases

(T/°C)

660 n-C₅Hn CH₃ H H H

662 n-C_{7 15} CH₃ H H H

664 n-C Hig CH₃ H H H

666 CH₂=CH CH₃ H H H

667 CH₂=CH-CH₂ CH₃ H H H

668 CH₃ CH₃ CH₃ H H

676 n-CgHig CH₃ CH3 H H

678 CH₂=CH CH₃ CH₃ H H

679 CH₂=CH-CH CH₃ CH₃ H H

681 C₂H_δ C₂H_δ H H H

682 n-C₃H₇ C₂H_δ H H H

683 n-C₄H₉ C₂H₅ H H H

684 -CsHu C₂H_δ H H H

688 7-CgHig C₂H₅ H H H

689 π-CιoH₂ C₂H₅ H H H

690 CH₂=CH C₂H₅ H H H

692 CH₃ C₂H₅ CH₃ H H

»

No. R R R"¹ L¹¹ L¹¹' Phases (T/°C)

728 CH₃ CH₃ H H F

730 π-C₃H₇ π-C₃H₇ H H F

732 n-C₅Hn n-C₅Hn H H F

733 /7-CβH ₃ n-C₈Hi₃ H H F

735 π-C₈Hι₇ n-C₈H ₇ H H F

736 n-CgHig 7-CgHig H H F

737 n-CιoH₂ι n-C oH2i H H F

738 CH₂=CH CH₂=CH H H F

740 CH₃ CH₃ H F H

742 π-C₃H₇ n-C₃H₇ H F H

743 n-C₄H₉ n-C₄H₉ H F H

744 n-C₅Hn n-C₅Hιι H F H

745 π-CβH s /7-C6H 3 H F H

747 A7-C₈Hι₇ π-C₈Hι₇ H F H

748 π-CgHi /7-CgHig H F H

749 n-CιoH2i π-C oH₂ H F H

750 CH₂=CH CH₂=CH H F H

752 CH₃ CH₃ H F F

754 n-C₃H₇ n-C₃H₇ H F F

756 π-C₅Hn n-C₅Hn H F F

757 π-CβHis π-C₈Hi₃ H F F

759 π-C₈H₁₇ π-C₈Hι₇ H F F

760 D-CgHig /7-CgHig H F F No. R R R"¹ L¹¹ L^{11 '} Phases (T/°C)

761 / CιoH₂ι /7-CιoH₂ι H F F

762 CH₂=CH CH₂=CH H F F

764 CH₃ CH₃ CH₃ H F

765 C₂H₅ C₂H_δ CH₃ H F

766 n-C₃H₇ n-C₃H₇ CH₃ H F

767 t7-C₄Hg π-C Hg CH₃ H F

768 π-C₅Hn π-C₅Hn CH₃ H F

770 π-C₇H₁₅ n-C₇Hi5 CH₃ H F

771 π-C₈Hι₇ n-C₈Hι₇ CH₃ H F

772 π-CgHig 7-CgHig CH₃ H F

773 π-CιoH2i π-CιoH₂ CH₃ H F

774 CH₂=CH CH₂=CH CH₃ H F

775 CH₂=CH-CH₂ CH₂=CH-CH₂ CH₃ H F

776 CH₃ CH₃ CH₃ F H

778 π-C₃H₇ π-C₃H₇ CH₃ F H

779 /7-C₄Hg />C₄H₉ CH₃ F H

780 π-C₅Hn π-C₅Hn CH₃ F H

782 π-C₇Hi₅ π-C₇H s CH₃ F H

783 n-C₈Hι₇ Λ7-C₈H₁₇ CH₃ F H

784 A7-CgHιg n-CgHi CH₃ F H

785 /7-CιoH₂ι fϊ-CιoH21 CH₃ F H

786 CH₂=CH CH₂=CH CH₃ F H

787 CH₂=CH-CH₂ CH₂=CH-CH₂ CH₃ F H

788 CH₃ CH₃ CH₃ F F

789 C₂H_δ C₂H_δ CH₃ F F

790 n-C₃H₇ n-C₃H₇ CH₃ F F

793 /7-C₈Hi₃ n-C₈H ₃ CH₃ F F

794 π-C₇Hi5 π-C₇Hιs CH₃ F F No. R R R >.1 11 11' Phases (T/°C)

795 /7-C₈H₁₇ π-C₈H_i7 CH₃ F F

796 π-C₉H₁₉ π-CgH g CH₃ F F

797 π-C₁₀H₂ι n-CιoH₂ CH₃ F F

798 CH₂=CH CH₂=CH CH₃ F F

799 CH₂=CH-CH₂ CH =CH-CH₂ CH₃ F F

Examples 800 to 943

Analogously to example 1 the following compounds are prepared:

No. R R R" L¹¹ L¹¹ Phases (T/°C)

802 n-C₃H₇ CH₃ H H H

804 π-C₅Hn CH₃ H H H

806 n-C₇H₁₅ CH₃ H H H

808 7-CgHig CH₃ H H H

810 CH₂=CH CH₃ H H H

LO o LO o LO

LO CM CM CO CO

No. R R R"¹ L¹¹ L Phases (T/°C)

845 π-C oH₂ C₂H₅ CH₃ H H

846 CH₂=CH C₂H₅ CH₃ H H

847 CH₂=CH-CH₂ CH₃ CH₃ H H

848 CH₃ A7-C₃H₇ H H H

849 C₂H_δ n-C₃H₇ H H H

850 n-C₃H₇ n-C₃H₇ H H H

851 t7-C₄Hg A7-C₃H₇ H , H H

857 /?-CιoH₂ι /?-C₃H₇ H H H

858 CH₂=CH n-C₃H₇ H H H

860 CH₃ /7-C₃H₇ CH₃ H H

862 n-C₃H₇ n-C₃H₇ CH₃ H H

864 π-C₅Hn /7-C₃H₇ CH₃ H H

865 A7-C₈Hι₃ π-C₃H₇ CH₃ H H

866 π-C₇H₁₅ π-C₃H₇ CH₃ H H

867 t?-C₈Hι₇ A7-C₃H₇ CH₃ H H

868 A7-CgHιg n-C₃H₇ CH₃ H H

869 /7-C10H21 π-C₃H₇ CH₃ H H

870 CH₂=CH A7-C₃H₇ CH₃ H H

871 CH₂=CH-CH₂ CH₃ CH₃ H H

872 CH₃ CH₃ H H F

874 n-C₃H₇ n-C₃H₇ H H F

875 n-C₄H₉ n-C₄H₉ H H F

876 /7-C₅H11 A7-C₅Hn H H F

877 π-C₈Hι₃ π-CeH ₃ H H F

No. R R R"¹ L^{11 11'} Phases (T/°C)

879 n-C₈Hι₇ /-C₈Hi7 H H F

880 f?-CgHi9 n-CgHig H H F

881 t7-ClθH21 / CιoH₂ι H H F

882 CH₂=CH CH₂=CH H H F

884 CH₃ CH₃ H F H

885 C₂H₅ C₂H₅ H F H

886 n-C₃H₇ n-C₃H₇ H F H

887 n-C_{4 9} r?-C₄H₉ H F H

889 7-C₈H 3 π-CeH ₃ H F H

890 π-C₇H₅ n-C₇H₁₅ H F H

891 t?-C₈H₁₇ 7-C₈H₁₇ H F H

892 n-CgH g n-CgHig H F H

893 n-CιoH2i /T-C10H21 H F H

894 CH₂=CH CH₂=CH H F H

896 CH₃ CH₃ H F F

898 π-C₃H₇ n-C₃H₇ H F F

899 n-C₄H₉ n-C₄H₉ H F F

903 n-C₈H₁₇ /7-C₈Hi7 H F F

904 n-C H g π-CgHig H F F

905 n-CoH₂ι n-CoH₂ι H F F

906 CH₂=CH CH₂=CH H F F

907 CH₂=CH-CH₂ CH2=CH-CH2 H F F

908 CH₃ CH₃ CH₃ H F

909 C₂H₅ C₂H₅ CH₃ H F

910 π-C₃H₇ A7-C₃H₇ CH₃ H F

911 π-C₄H₉ n-C₄H₉ CH₃ H F

912 7-C5H11 7-C₅Hn CH₃ H F No. R R' R"¹ L¹¹ L¹¹' Phases (T/°C)

913 n-C₈Hi₃ π-CβHι₃ CH₃ H F

914 r/-C₇H₁₅ n-C₇H₁₅ CH₃ H F

915 /7-C₈H₁₇ n-C_{8 π} CH₃ H F

916 fϊ-CgH g π-CgHi CH₃ H F

917 /7-C10H2I n-CιoH₂ι CH₃ H F

918 CH₂=CH CH₂=CH CH₃ H F

920 CH₃ CH₃ CH₃ F H

921 C₂H_δ C₂H₅ CH₃ F H

922 π-C₃H₇ r?-C₃H₇ C^"H₃ F H

923 f)-C Hg π-C₄H₉ CH₃ F H

924 /7-C5H11 n-C₅Hn CH₃ F H

925 t?-C₈Hi₃ /7-C6H ₃ CH₃ F H

926 n-C₇His π-C₇H₁₅ CH₃ F H

927 n-C₈Hι₇ π-C₈H₁₇ CH₃ F H

928 /?-CgHιg 7-CgHig CH₃ F H

929 n-CιoH₂ι ?-CιoH2i CH₃ F H

930 CH₂=CH CH₂=CH CH₃ F H

932 CH₃ CH₃ CH₃ F F

933 C₂H_δ C₂H_δ CH₃ F F

934 A7-C₃H₇ /7-C₃H₇ CH₃ F F

936 π-C₅Hιι π-C₅Hn CH₃ F F

937 t7-C₈Hι₃ π-CeHi₃ CH₃ F F

938 n-C₇Hi5 π-C₇Hιs CH₃ F F

939 n-C₈Hi₇ n-C₈Hi7 CH₃ F F

940 t7-CgHi₉ /7-C₉H1₉ CH₃ F F

941 n-CιoH₂ι n-CιoH₂ι CH₃ F F

942 CH₂=CH CH₂=CH CH₃ F F

943 CH₂=CH-CH₂ CH₂=CH-CH₂ CH₃ F F

Examples 944 to 1087 Analogously to example 1 the following compounds are prepared:

No. R R R" L¹¹ L^11' Phases (T/°C)

944 CH₃ CH₃ H H H

945 C₂H₅ CH₃ H H H

946 n-C₃H₇ CH₃ H H H

947 π-C₄H₉ CH₃ H H H

948 7-C₅Hn CH₃ H H H

952 π-CgH g CH₃ H H H

954 CH =CH CH₃ H H H

956 CH₃ CH₃ CH₃ H H

957 C₂H₅ CH₃ CH₃ H H

^■ 958 n-C₃H₇ CH₃ CH₃ H H

960 n-C₅Hn CH₃ CH₃ H H

961 Λ-C₆H₁₃ CH₃ CH₃ H H

962 n-C₇Hι₅ CH₃ CH₃ H H

963 n-C₈H₁₇ CH₃ CH₃ H H

964 t7-CgHig CH₃ CH₃ H H

o. R R R"¹ L¹¹ L^11' Phases (T/°C)

966 CH₂=CH CH₃ CH₃ H H

967 CH₂=CH-CH₂ CH₃ CH₃ H H

968 CH₃ C₂H₅ H H H

969 C₂H₅ C₂H₅ H H H

970 n-C₃H₇ C₂H_δ H H H

971 π-C₄H₉ C₂H₅ H H H

973 n-C₆Hι₃ C₂H₅ H H H

974 π-C₇H₁₅ C₂H₈ H H H

975 π-C₈Hι₇ C₂H_δ H^" H H

978 CH₂=CH C2H₅ H H H

980 CH₃ C₂H₅ CH₃ H H

982 n-C₃H₇ C2H₅ CH₃ H H

984 t7-C₅Hn C₂H_δ CH₃ H H

988 n-CgHig C₂Hδ CH₃ H H

990 CH₂=CH C₂H₈ CH₃ H H

991 CH₂=CH-CH₂ CH₃ CH₃ H H ^■

992 CH₃ n-C₃H₇ H H H

993 C₂H₅ n-C₃H₇ H H H

995 π-C₄H₉ n-C₃H₇ H H H

996 π-C₅H ι π-C₃H₇ H H H

999 π-C₈H₁₇ π-C₃H₇ H H H No. R R R"¹ L¹¹ L¹¹' Phases (T/°C)

1001 π-CιoH₂₁ n-C₃H₇ H H H

1002 CH₂=CH π-C₃H₇ H H H

1003 CH₂=CH-CH₂ A7-C₃H₇ H H H

1004 CH₃ π-C₃H₇ CH₃ H H

1005 C₂H₅ π-C₃H₇ CH₃ H H

1006 / C₃H₇ t7-C₃H₇ CH₃ H H

1007 π-C₄H₉ π-C₃H₇ CH₃ H H

1008 n-C₅Hn π-C₃H₇ CH₃ H H

1009 r/-C₆Hi3 /?-C₃H₇ CH₃ H H

1010 n-C₇H₁₅ π-C₃H₇ CH₃ H H

101 1 π-C₈Hi7 π-C₃H₇ CH₃ H H

1012 t7-CgH₁₉ A7-C₃H₇ CH₃ H H

1013 π-C₁₀H₂ι π-C₃H₇ CH₃ H H

1014 CH₂=CH n-C₃H₇ CH₃ H H

1015 CH₂=CH-CH₂ CH₃ CH₃ H H

1016 CH₃ CH₃ H H F

1017 C₂H₅ C₂H₈ H H F

1018 n-C₃H₇ π-C₃H₇ H H

1019 /7-C₄Hg A7-C₄H H H F

1020 n-C₅Hn A7-C5H1 H H F

1021 / C₆H₁₃ π-CβHi₃ H H F

1022 /7-C₇Hi_δ 7-C₇H₁₅ H H F

1023 n-C₈Hi7 n-C₈Hι₇ H H F

1024 / CgHιg π-CgHig H H F

1025 t7-CιoH₂ι /7-C10H21 H H F

1026 CH₂=CH CH₂=CH H H F

1027 CH₂=CH-CH₂ CH₂=CH-CH₂ H H F

1028 CH₃ CH₃ H F H

1030 n-C₃H₇ π-C₃H₇ H F H

1031 r?-C₄H₉ / -C₄Hg H F H

1032 n-CsHn π-C₅Hn H F H

1033 π-C₆Hι₃ π-CβH ₃ H F H No. R R R"¹ L¹¹ L¹¹' Phases (T/°C)

1034 /7-C7H15 t7-C₇H_i5 H F H

1035 π-C₈Hi7 π-C₈H_i7 H F H

1036 π-C₉Hιg n-CgHig H F H

1037 A7-C10H21 A7-C oH₂ H F H

1038 CH₂=CH CH₂=CH H F H

1039 CH₂=CH-CH₂ CH =CH-CH₂ H F H

1042 π-C₃H₇ n-C₃H₇ H F F

1043 A7-C₄Hg /7-C₄Hg H F F

1044 n-C₅Hιι n-C₅Hιι H F F

1045 n-C₆H₁₃ π-C₈Hi3 H F F

1047 n-C₈H_i7 π-C₈H ₇ H F F

1048 n-CgHig n-CgHig H F F

1049 /7-C10H21 r?-CιoH2 H F F

1050 CH₂=CH CH₂=CH H F F

1052 CH₃ CH₃ CH₃ H F

1053 C₂H₅ C₂H₅ CH₃ H F

1054 π-C₃H₇ n-C₃H₇ CH₃ H F

1055 /7-C₄H₉ n-C₄H CH₃ H F

1056 t7-C₅Hn n-C₅Hιι CH₃ H F

1057 n-C₆Hi₃ π-C₈Hι₃ CH₃ H F

1058 n-C₇His n-C₇Hι₅ CH₃ H F

1059 t7-C₈H₁₇ 7-C₈H₁₇ CH₃ H F

1060 /7-CgHig π-CgH 9 CH₃ H F

1061 π-Cι₀H₂ι n-CιoH2i CH₃ H F

1062 CH₂=CH CH₂=CH CH₃ H F

1063 CH₂=CH-CH₂ CH₂=CH-CH₂ CH₃ H F

1064 CH₃ CH₃ CH₃ F H

1066 n-C₃H₇ π-C₃H₇ CH₃ F H

1067 A7-C₄Hg n-C₄Hg CH₃ F H ω o ro ro en en o en o tn

red:

T C I.

5% of the chiral agent R-5011 have been solved in the achiral liquid crystal mixture H-0 with the composition and properties given in table 1 below.

Table 1 : Composition and Properties of Host Mixture H-0

Compound Concentration Physical Properties

Abbreviation / mass-%

GZU-3A-N 15.0 T(N, I) 56.5 °C

GZU-4A-N 15.0

GZU-40-N 15.0 Δn (20°C, 589 nm) = 0.164

UZU-3A-N 8.0

CUZU-2-N 9.0

CUZU-3-N 9.0

CUZU-4-N 9.0

HP-3N.F 6.0

HP-4N.F 6.0

HP-5N.F 8.0

Σ 100.0

The resulting mixture CM was filled into an electro optical test cell with inter-digital electrodes on one substrate side. The electrode width was 10 μm, the distance between adjacent electrodes was 10 μm and the cell gap was also 10 μm. This test cell has been evaluated electro-optically between crossed polarisers.

At low temperatures, the filled cell showed the typical texture of a chiral nematic mixture, with an optical transmission between crossed polarisers without applied voltage. On heating, at a temperature of 36°C the mixture was optically isotropic, being dark between the crossed polarisers. This indicated the transition from the chiral nematic phase to the blue phase at 36°C. This temperature is called Ti or T_trans ■

Up to a temperature of 43°C the cell showed a clear electro optical effect under applied voltage, for example at 38°C, applying a voltage of 46 V lead to a maximum of the optical transition. This temperature is called T₂ and threspective voltage is called V_max or V₁₀₀. At a temperature of 43°C the voltage needed for a visible electro-optical effect started to increase strongly, indicating the transition from the blue phase to the isotropic phase at this temperature.

The temperature range (ΔT(BP)), where the mixture can be used electro- optically in the blue phase was identified as ranging from 36°C to 43°C, i.e. as being 7° wide (= T₂ - Ti = 43°C - 36°C). The results are listed in table 2 below. Further the response times for switching on (x_on) and for switching off (τ_0ff) have been determined. The response times decrease with increasing temperature above Ti and the temperature at which both response times have fallen below 5 ms each is called T₃. This is the case in this comparative use example at a temperature of 43°C or slightly above. Thus, the range of usable flat behaviour i.e. the usable flat range (ΔT(FR)), defined as ΔT(FR) = T₂ - T₃, in case T₂ > T₃ and ΔT(FR) = 0, in case T₂ < T₃, is 0° in this comparative use example.

Table 2: Results

Remarks: *: upper limit not easy to detect, n.d.: not determined.

Use-example 1

In this use-example 10 % of the respective compound of examples 1 to 6 and 5% of the chiral agent R-5011 have been solved together in the achiral liquid crystal mixture H-0 used in the comparative use example 1 described just above. The resultant mixtures H-1 to H-6 had the composition and properties given in the following table.

The resulting mixtures H-1 to H6 are filled into respective electro optical test cell like that used in the comparative example and investigated as described there. The results are listed in table 2 above.

At low temperatures, the cell filled with H-1 showed the typical texture of a chiral nematic mixture, with an optical transmission between crossed polarisers without applied voltage. On heating, at a temperature of -5.5°C the mixture was optically isotropic, being dark between the crossed polarisers. This indicated the transition from the chiral nematic phase to the blue phase at -5.5°C Up to a temperature of 12.0°C, the cell showed a clear electro optical effect under applied voltage. The temperature range (ΔT(BP)), where the mixture can be used electro- optically in the blue phase was identified as ranging from -5.5°C to 12°C, i.e. as being 17.2° wide (= T₂ - Ti = 12°C - -5.5°C). This is significantly larger than the respective range of 7.0°, being found in the chiral reference mixture CM with only 5% of R-5011 added to mixture H-0 and at the same time the phase range of the blue phase is shifted significantly closer to ambient temperature, which facilitates practical handling. And, at the same time, the operation voltage is reduced.

Further, again the response times for switching on (τ_on) and for switching off (τ₀ff) have been determined. The response times decrease with increasing temperature above Ti and the temperature at which both response times have fallen below 5 ms each (T₃) is 11 °C here. Thus, ΔT(FR) is ΔT(FR) = 1 °(= T₂ - T₃, =12°C - 11 °C) in this use example.

For use examples 1-2 to 1-6 comparable results are obtained, as e.g. included in tables 2 and 3.

Table 3: Results

Remarks: n.d.: not determined. Use-example 2

In this use-example various amounts of the compound of example 1 , in each case together with 5 % of the chiral agent R-5011 , have been solved in the achiral liquid crystal mixture A-0 with the composition and properties given in the following table.

Table 4: Composition of Host Mixture A-0

Compound Concentration

Abbreviation / mass-%

AUUQU-3-N 11.76

CUZU-3-N 10.59

CUZU-4-N 10.59

HP-3N.F 9.41

AUUQU-3-OT 11.77

AUUQU-3-F 10.59

AUUQU-3-T 9.41

AUUQP-3-T 5.88

PUZU-2-F 10.59

PUZU-5-F 9.41

Σ 100.00

The results are shown in table 5 below. Table 5: Results

Remarks: n.d.: not determined.

Use-example 3

In this use-example 5 % of each the compound of example 1 and of the chiral agent R-5011 have been solved together in the achiral liquid crystal mixture B-0 with the composition and properties given in following table.

Table 6: Composition of Host Mixture B-0

Compound Concentration

Abbreviation / mass-%

AUUQU-3-N 12.0

AUZU-3-N 12.0

AUZU-5-N 12.0

GZU-2-F 9.0

UZU-2-F 9.0

AUUQU-3-OT 12.0

AUUQU-3-F 8.0

AUUQU-3-T 8.0

PUZU-2-F 6.0

PUZU-5-F 12.0

Σ 100.0

The results are included for comparison in table 5 above. Use-example 4

In this use-example a nematic liquid crystal mixture (called C) has been prepared, which contains about 10 % of the compound of example 1 and evaluated for its physical properties, as given in the following table.

Table 7: Composition and Properties of Mixture C

Compound Concentration Physical Properties

Abbreviation / mass-%

Cpd. Ex. 1 10.07 T(N, I) 69.2 °C

PCH-5F.F 8.99

PCH-6F.F 7.19 Δn (20°C, 589 nm) = 0.088

PCH-7F.F 5.40

CCP-20CF3 7.19 Δε(20°C) +6.3

CCP-30CF3 10.79

CCP-4 OCF3 6.39

CCP-50CF3 9.89

ECCP-30CF3 4.50

ECCP-50CF3 4.50

BCH-3F.F 10.79

BCH-5F.F 8.99

CBC-33F 1.80

CBC-53F 1.80

CBC-55F 1.80

Σ 100.00

Claims

Claims

Mesogenic compound, characterized in that it comprises a phenyl ring, which is bearing two mesogenic groups in otho position to each other.

Compound according to claim 1 , characterized in that they are substituted by one cyclic group or by two non-cyclic groups on the opposite side of said two mesogenic groups.

3. Compound according to claim 1 , characterized in that it is a compound of formula I

wherein

R¹¹ and R¹² are, independently of each other, H, F, Cl, CN, NCS, SF₅ , S0₂CF₃ or alkyl which is straight chain or branched, is unsubstituted, mono- or polysubstituted by F, Cl, or CN, and in which one or more non-adjacent CH₂ groups are optionally replaced, in each case independently from one another, by -0-, -S-, -NH-, -NR⁰¹-, -SiR⁰¹R⁰²-, -CO- , -COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, -CY⁰¹=CY⁰²- or -C≡C- in such a manner that O and/or S atoms are not linked directly to one another, R ι0^u1^ι and R 02 are, independently of each other, H or alkyl with 1 to 12 C-atoms,

Y⁰¹ and Y⁰² are, independently of each other, F, Cl or CN, and alternatively one of them may be H,

R »1¹3^J and R 14 have, independently of each other, one of the meanings given for R >11 or altenatively together form one of the cyclic groups CG-1 to CG-6

CG-1

— CHj cH

R¹⁵ and R¹⁶. have, independently of each other, one of the meanings given for R¹¹ or altenatively, again independently of each other, have one of the meanings given for

and , are, indpendently of each

other and, in case and/or

occurring more than once, also these are in each occurrence independently of each other, an aromatic and/or alicyclic ring, or a group comprising two or more fused aromatic or- alicyclic rings, wherein these rings optionally contain one or more hetero atoms selected from N, O and/or S, and are optionally monosubstituted or polysubstituted by R,

R has one of the meanings gven for R¹¹ ,

Z¹¹ and Z¹² are, independently of each other, and in case Z¹¹ and/or Z¹² are occurring more than once, also these are in each occurrence independently of each other, -CO-O-, -0-CO-, -S-CO-, -CO-S-, -CO-NR⁰¹-, -NR⁰¹-CO-, -OCH₂-, -CH₂0-, -SCH₂-, -CH₂S-, -CF₂0-, -OCF₂-, -CF₂S-, -SCF₂-, -CH₂CH₂-,

-CF₂CH₂-, -CH₂CF₂-, -CF₂CF₂-, -CH=N-, -N=CH-, -N=N-, -CH=CR⁰¹-, -CR⁰¹=CH-, -CY⁰¹=CY⁰²-, -C≡C-, -(CH₂)₄-, -CH=CH-CO-0-, -0-CO-CH=CH- or a single bond,

Y¹¹ and Y¹² are, independently of each other, H, F, Cl, CN or

NCS,

n and m are, independently of each other 1 , 2, 3 or 4 and

p is an integer from 1 to 6.

4. Compound according to at least one of claims 1 to 3, characterized in that it comprises a cyclic group selected from the group of cyclic groups of partial formulae CG-1 to CG-6.

5. Compound according to at least one of claims 1 to 4, characterized in that it comprises two mesogenic groups

which are identical to each other.

6. Compound according to at least one of claims 1 to 5, characterized in that at least one of Z¹¹ and Z¹² is -CF₂-0- or -0-CF₂-.

7. Medium, characterized in that it comprises a compound according to at least one of claims 1 to 6.

8. Medium according to claim 7, characterized in that it is a mesogenic medium.

9. Medium according to at least one of claims 7 and 8, characterized in that it is a light modulation medium.

10. Medium according to at least one of claims 7 to 9, characterized in that it has a blue phase.

11. Light modulation element, characterized in that it comprises a medium according to at least one of claims 7 to 10.

12. Use of a compound according to at least one of claims 1 to 6 in a mesogenic medium.

13. Use of a medium according to at least one of claims 7 to 10 in a light modulation element.

4. Electro-optical display, characterized in that it comprises a medium according to at least one of claims 7 to 10.