GB2388841A - Polymerisable mesogenic or liquid crystalline compounds comprising an acetylene group and a heterocyclic group - Google Patents

Abstract

Polymerisable compounds of formula I in which P is a polymerisable group, Sp is a spacer group or a single bond, X, Z<1> and Z<2> are each independently various residues or a single bond, A<1> and A<2> are each independently aliphatic or aromatic, optionally substituted carbocyclic or heterocyclic groups, m1 and m2 are each independently 0, 1, 2, 3, 4 or 5 with m1+m2=1, 2, 3, 4 or 5 and R is H or one of various substituent groups, including a group X-Sp-P. The compounds contain at least one heterocyclic group A<1> or A<2>. Preferably, the polymerisable group P is a vinyl group, an acrylate group, a methacrylate group, a propenyl ether group or an epoxy group. The compounds may be mesogenic or liquid crystalline compounds and the compounds, or polymers thereof, have various uses including in liquid crystal displays, as electrode materials in batteries and in electrophotographic recording. <EMI ID=1.1 HE=9 WI=102 LX=637 LY=1365 TI=CF>

Description

- 238884 1

Polymerisable Heterocyclic Acetylenes Field of the Invention

5 The invention relates to new Polymerisable mesogenic or liquid crystalline heterocyclic acetylenes, to Polymerisable mesogenic or liquid crystalline mixtures and anisotropic polymers prepared thereof, and to the use of the new compounds and the mixtures and polymers prepared thereof in optical and electrooptical devices, adhesives, 10 synthetic resins with anisotropic mechanical properties, cosmetics, diagnostics, liquid crystal pigments, decorative and security applications, nonlinear optics, optical information storage, electronic devices like organic field effect transistors (PET or OFET),

electroluminescent devices, or as chiral dopants.

Backoround and Prior Art

Polymerisable mesogenic or liquid crystalline compounds, which are also known as reactive mesogenic compounds, have been described 20 in prior art for various purposes. For example they can be used for

the preparation of linear or crosslinked liquid crystal side chain polymers. Furthermore, they can be aligned in their liquid crystal phase and subsequently polymerized in situ to give linear or crosslinked liquid crystal polymer films with uniform orientation of 25 high quality. These films can be used as optical elements like polarisers or compensators in flat panel displays, as described for example in EP 0 397 263, WO 98/00475, WO 98/04651 or WO 98/12584.

30 Polymerisable mesogenic compounds have also been suggested for use in polymerized cholesteric liquid crystal films or coatings that show selective reflection of visible light and are suitable as optical films like narrowband or broadband reflective polarizers or colour filters as described for example in EP 0 606 940 or WO 97/35219, or 35 for the preparation of liquid crystal pigments, as described for example in WO 97/30136. Other important fields of use are- security

- 2 markings as described for example in US 5,678,863 or hot stamping foils as described for example in GB 2,357,061.

Further to the use as optical films in displays, polymerisable 5 mesogenic compounds have been suggested for use in the active, switchable layer of a liquid crystal display.

For example, displays are known which are switched between transparent and scattering states and comprise a low molar mass 10 liquid crystal (LC) medium and a phase-separated polymerized liquid crystal material, like for example PDLC (polymer dispersed liquid crystal) displays as described in WO 93/22397, or polymer gel or polymer network displays of the scattering type, as described in US 5,538,768, US 5,543,075 or EP 0 451 905.

Furthermore, displays are known wherein a low molar mass LC medium is switched between two non-scattering states, like conventional displays of e.g. the TN or STN, ECB, VA or IPS mode, and which further comprise a polymerised liquid crystal material in 20 order to create a multidomain structure to improve the contrast at wide viewing angles or to stabilise the different switching states in order to reduce the driving voltage and the switching times. Such displays are described for example in US 5,189, 540, US 6,177,972, EP 0 903 392, and Hasebe et al., Jpn.J.Appl.Phys.1994, 33, 6245.

For the above applications, usually mixtures of two or more polymerisable mesogenic compounds are used, as they have lower melting points and broader liquid crystal phases than single compounds. It is desired to have available polymerisable mixtures 30 exhibiting a liquid crystal phase, preferably a nematic or chiral nematic phase, at room temperature, so that it is possible to carry out alignment and polymerization at low temperatures. For this purpose, it is advantageous if the single polymerisable compounds do already exhibit broad liquid crystalline phases.

- 3 For use in the switchable layer of liquid crystal displays, where they are typically mixed with a low molar mass LC medium, it is often required that the polymerisable mesogenic compounds have properties, like the liquid crystal phase range and birefringence, that 5 are similar to those of the LC medium. When used in switchable displays that are not of the scattering type, and where the polymerized material is not macroscopically phase separated from the low molar mass LC medium, the polymerisable compounds should preferably show good miscibility with the LC medium.

The polymerisable mesogenic compounds described in prior art,

however, often negatively affect the liquid crystal phase behaviour of LC mixtures, show poor solubility in low molar mass LC media and have unfavourably low values of the birefringence.

Polymerizable mesogenic tolanes or phenylacetylenes have been reported in prior art to show high birefringence values, and have

been disclosed e.g. in JP-A-05-339189, JP-A-07-017910, EP-A-O 659 865, JPA-08-231958, JP-A-11-147853, GB-A-2 351 734, JP-A

20 2000-281628, JP-A-2000-281629 and US-A-2002/0006479.

However, these compounds often do not have sufficiently high birefringence or, when used in an LC mixture, do often negatively influence the properties of the mixture, or do not show sufficient stability against UV light.! Thus, there is a demand for polymerisable mesogenic compounds that do not have the disadvantages mentioned above, in particular for compounds that have high birefringence, which can be used for the preparation of oriented liquid crystal polymer films or as 30 compounds in the active layer of switchable LC devices in a mixture with low molar mass LC media.

Furthermore, regarding the broad range of applications for polymerisable mesogenic compounds it is desirable for the expert to 35 have available further compounds of this type which are easy to synthesize and fulfill the various requirements as described above.

- 4 It was an aim of the invention to provide polymerisable mesogenic compounds with the advantageous properties mentioned above, thus extending the pool of polymerisable mesogenic compounds available 5 to the expert. Other aims of the present invention are immediately evident to the person skilled in the art from the following detailed description.

It was found that these aims can be achieved by providing 10 polymerisable compounds according to the present invention.

Summary of the Invention

One object of the present invention are polymerisable compounds of 15 formula I P-sp-x-(A4-z')m'-cc-(z2-A2)m2-R I wherein P is a polymerisable group, Sp is a spacer group or a single bond, 25 O

X is-O-,-S-,-CO-,-COO-,-OCO-,-CH CH-,-OCO-O- -S CO-, -CO-S-, -CO-NR -, NR -CO-, -OCH2-, -CH2O-, -SCH2

-CH2S-, -CH=CH-COO-, -OOC-CH=CH-, CH2CH2 or a single bond, Z' and z2 are each independently -COO-, -OCO-, -CH2CH2-, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-,

-CF2S-, -SCF2-, -CH2CH, -CF2CH2-, -CH2CF2-,

-CF2CF=, -CH=CH-, -CH=CH-, -CF=CH-, -CH=CF-,

35 CF=CF-, -CH=CH-COO-, -OCO-CH-CH-, -C-C- or a single bond,

- 5- A' and A2 are each independently an aliphatic or aromatic carbocyclic or heterocyclic group with up to 16 C atoms that may also comprise fused rings and may be 5 unsubstituted, mono- or polysubstituted with L, L is F. Cl, Br, I, CN, NO2 or alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl or alkylcarbonlyoxy with 1 to 7 C atoms, wherein one or more H atoms may be substituted by F or Cl.

m1 and m2 are each independently 0, 1, 2, 3, 4 or 5, with m1 m2 being 1, 2, 3,40r5, R is H. F. Cl, Br, I, CN, SON, SF5, straight chain or branched 15 alkyl with up to 25 C atoms which may be unsubstituted, mono- or polysubstituted by F. Cl, Br, I or CN, it being also possible for one or more non-adjacert CH2 groups to be replaced, in each case independently from one another, by 0-, -S-, -NH-, -NR -, -SiR R -, -CO-, -COO-, -OCO-, -OCO 20 0-, -S-CO-, -CO-S-, -SO2, -SO-O-, -O-SO-, -(:H=CH- or C--C- in such a manner that O and/or S atoms are not linked directly to one another, or is P-Sp-X, and R and R are independently of each other H or alkyl with 1 to 4 C 25 atoms, wherein the compounds contain at least one heterocyclic group A' or A2.

Another object of the present invention is a polymerisable liquid crystal 30 mixture comprising at least one compound of formula 1.

Another object of the present invention is an anisotropic polymer or polymer film prepared from one or more compounds of formula I or from a polymerisable liquid crystal mixture comprising at least one 35 compound of formula 1.

-6 Another object of the present invention is the use of the polymerisable compounds of formula 1, the polymerisable mixtures and polymers prepared thereof in optical films, polarisers, compensators, beam splitters, reflective films, alignment layers, 5 colour filters, holographic elements, hot stamping foils, coloured images, decorative or security markings, liquid crystal pigments, adhesives, synthetic resins with anisotropic mechanical properties, cosmetics, diagnostics, nonlinear optics, optical information storage, as chiral dopants, in electronic devices like for example field effect

10 transistors (FET) as components of integrated circuitry, as thin film transistors in flat panel display applications or for Radio Frequency Identification (RFID) tags, or in semiconducting components for organic light emitting diode (OLED) applications such as electroluminescent displays or backlights of e.g. liquid crystal 15 displays, for photovoltaic or sensor devices, as electrode materials in batteries, as photoconductors, or for electrophotographic applications like electrophotographic recording.

Another object of the present invention is a liquid crystal display 20 comprising in its active layer at least one compound of formula I or a mixture comprising at least one compound of formula 1, or a polymer obtained from such a mixture.

Definitions of Tends 25 The term 'film' as used in this application includes self-supporting, i.e. free-standing, films that show more or less pronounced mechanical stability and flexibility, as well as coatings or layers on a supporting substrate or between two substrates.

30 The term 'mesogenic compounds' as used in the foregoing and the following should denote compounds with a rod-shaped, lath-shaped or diskshaped mesogenic group, i.e. a group with the ability to induce mesophase behaviour. These compounds do not necessarily have to exhibit mesophase behaviour by themselves. It is also 35 possible that these compounds show mesophase behaviour only in mixtures with other compounds or when the mesogenic compounds

( - 7 or the mixtures comprising them are polymerized. Rod-shaped and lath-shaped mesogenic groups are especially preferred.

For the sake of simplicity, the term 'liquid crystal material' is used 5 hereinafter for both liquid crystal materials and mesogenic materials, and the term 'mesogen' is used for the mesogenic groups of the material.

Detailed DescriDtion of the Invention 10 The compounds of formula I are especially suitable for use in liquid crystalline polymerisable compositions where they lead to a high birefringence. They do not have to exhibit mesophase behaviour but show mesophase behaviour in mixtures with other compounds.

However, compounds of formula I with broad mesophases are 15 especially preferred. Furthermore, the compounds of formula I show a tendency to suppress crystallization of the mixture and have an improved UV stability. In compounds with nitrogen and sulphur heterocycles the non-bonding elecgrons of the heteroatom will contribute to overall conjugation, which is an advantage in particular 20 when used in semiconducting or electroluminescent applications.

Particularly preferred are compounds of formula i, wherein - m1'm2=2,30r4, 25 - m1 and m2 are different from 0, - m1 is1 or2andm2is1 or2, - at least one group A' or A2 in a-position to the acetylene group is a heteroaromatic group, 30 - Z' and Z2 are selected from -COO-, -OCO- and C=C-, - risO, - ris1 or2, - r is 1 or2 and L is F. 35 - R has one of the meanings of P-Sp-X - -Sp-X- is different from a single bond,

-8 - Sp is alkylene with 1 to 12 C atoms which is optionally mono- or polysubstituted by F and wherein one or more non-adjacent CH2 groups are optionally replaced, in each case independently from one another, by-O-, CH=CH- or-C=C-, 5 - X is -O-, -COO-, -OCO-, -OCOO- or a single bond.

- Sp and X are a single bond, L in formula I is preferably If, Cl, CN, Old, NO2, CH3, C2Hs, OCH3, 10 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, OCI 13 or GOCH3 A' and A2 in formula I are preferably an aromatic or alicyclic 5- or 6-membered 15 ring or a group compnsing two or three fused aromatic or alicyclic or 6 membered rings, wherein these rings may also contain one or more hetero atoms, in particular selected from N. O and S. and may also be mono- or polysubstituted by L. Very preferably A1 and A2 are aromatic groups.

20 Preferred groups A' and A2 in formula I are for example furan, pyrrol, thiophene, oxazole, thiazole, thiadiazole, imidazole, phenylene, pyridine, pyrimidine, pyrazine, indane, naphthalene, tetrahydronaphthalene, anthracene and phenanthrene.

25 Particularly preferably A' and A2 are selected from furane-2,5-dlyl, thiophen+2,5-diyl, pyrrol-2,dlyl, 1,4-phenylene, pyndine-2,5-diyl, pyrimidin - 2,5-diyl, naphthalene-2,6iyl, 1,2,3,4-tetrahydro-

naphthalene-2,6-dlyl, indane-2,5-dlyl, furthermore 1,4-cyclohexylene 30 in which, in addition, one or two non-adjacent CH2 groups may be replaced by O and/or S. it being possible for all these groups to be unsubstituted, mon or polysubstituted by L as defined above.

Preferably the groups (A'-Z')m1 and (Z2-A2)m2 in fonnula I contain only 35 monocyclic groups A' and A2. Very preferably the groups -(A'-Z')m'-and(Z2 A2)m2-denote independently of each other a group

-9 - with one or two five- or six-membered rings. The groups (A'Z')m' and -(Z2-A2),,2- may be identical or different.

Preferred subformulae for the groups -(A4-Z,),T,,- and -(Z2-A2),,2- are 5 listed below. For reasons of simplicity, Phe in these groups is 1,4 phenylene, Phe L is a 1,4-phenylene group which is substituted by 1 to 4 groups L as defined above, Fur is furan-2,5-dlyl, Thi is thiophene-2,5dlyl, Pyd is pyridine-2,5-dlyl and Pyr is pyrimidin+2,5 dlyl. The following list of preferred groups -(A'-Z')m'- and (Z2A2)m2 10 is comprising the subformulae 11-1 to 11-20 as well as their mirror images Phe- 11-1 -Fur- 11-2 15 -Thi- 11-3 -Pyd- 11 '1 -Pyr- 11-5 -PheL- I 1-6 Phe-Z-Phe- 11-7 20 -Fur-Z-Phe- 11-8 -Thi-Z-Phe- 11-9 -Pyd-Z-Phe- 11-1 0 Pyr-Z-Phe- 11-1 1 -Fur-Z-PheL- 11-1 2 25 -Thi-Z-PheL- 11-13 -Pyd-Z-PheL11-14 -Pyr-Z-PheL- 11-1 5 -Phe-Z-PheL- 11-1 6 -PheL-Z-PheL- 11-17 30 Pyr-Z-Pyd- 11-18 -Pyr-Z-Pyr- 11-1 9 -Pyd-Z-Pyd- 11-20 In these preferred groups Z has the meaning of Z' as given in 35 formula 1. Preferably Z is COO-, -OCO-, -CH2CH2-' -C_C- or a single bond.

- 10 Very preferably -(A'-Z')m'- and -(Z2-A2),,2 are, independently of each other, selected from the following formulae and their mirror images 5 3 O lla 10 > 11b (L)r 15 11c 3 11d No he 25 (L)r (L)r llf (L)r (L)r 30 SCOOT 119

(L)r 35 I__ 11h

- 11 (L)r _>COO Hi (L)r lik (L)r NCOON llm 1 5 (tar N lln 20 (tar - \) COO llo 25 (tar llp (or 30 SCOOT liq (or (or 35 llr

- 12 N lls (L)r lo= N:: lit wherein L has the meaning given above and r is 0, 1, 2, 3 or 4, preferably 0, 1 or2. (L)r 15 The group in these preferred formulae is very preferably L L L L L

denoting or furthermore 20 with L having each independently one of the meanings given above.

Particularly preferred are the subformulae lla, llc, llf, kg and lih, in particular the subformulae lla, lid and llf.

25 Especially preferred are compounds of formula I comprising at least one group wherein r is 1.

Further preferred are compounds of formula I comprising at least 30 (L)r two groups wherein r is 1 and/or at least one group (L), wherein r is 2.

run: - 1 3 R in formula I is preferably an alkyl, alkoxy, sulfanylalkyl, thiocarboxyl, alkylsulionyl or alkenyl radical.

If R in formula I is an alkyl or alkoxy radical, i.e. where the terminal 5 CH2 group is replaced by-O-, this may be straight-chain or branched.

It is preferably straight-chain, has 2, 3, 4, 5, 6, 7 or 8 carbon atoms and accordingly is preferably ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy, heptoxy, or octoxy, furthermore methyl, nonyl, decyl, undecyl, dodecyl, tridecyl, 10 tetradecyl, pentadecyl, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy or tetradecoxy, for example.

Oxaalkyl, i.e. where one CH2 group is replaced by-O-, is preferably straight-chain 2-oxapropyl (=methoxymethyl), 2- (-ethoxymethyl) or 15 3oxabutyl (-2-methoxyethyl), 2-, 3-, or 4-oxapentyl, 2-, 3-, 4-, or oxahexyl, 2-, 3-, 4-,, or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-,3-,4-,5-,6-,7-or8-oxanonylor2-,3-,4-,5-,6-,7-,8-or9 oxadecyl, for example.

20 If R in formula I is an alkylsulfanyl radical, i.e. alkyl where the CH2 group that is linked to the adjacent group is replaced by -S-, this 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 methylsulfanyl, ethylsulfanyl, propylsulfanyl, butylsulfanyl, 25 pentylsulfanyl, hexylsulfanyl, heptylsulfanyl, octylsulfanyl, furthermore nonylsulfanyl, decylsulfanyl, undecylsulfanyl or dodecylsulfanyl, for example.

If R is a thiocarboxyl or alkyisulfanylcarbonyl group, i.e. alkyl wherein the CH2 30 group that is linked to the neighbouring group is replaced byCO-S- or-S-CO this may be straight chain or branched. It is preferably straight chain, has 2, 3, 4, 5, 6, 7 or 8 carbon atoms and accordingly is preferably thioacetyl, thiopropionyl, thiobutyryl, thiopentanoyl, thiohexanoyl, thioheptanoyl, 35 thicoctanoyl, methylsulfanylcarbonyl, ethylsulfanylcarbonyl, propylsulfanylcarbonyl,

- 14 butylsulfanylcarbonyl, pentylsulfanylcarbonyl, hexylsulfanylcarbonyl or heptylsulfanylcarbonyl, for example.

If R is an alkylsulfonyl group, i.e. alkyl wherein the CH2 group that is 5 neighboured to the adjacent group is replaced by a sulfonyl group SO2-, this 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 methylsulfone, ethylsulfone, propylsulfone, butylsulfone, pentylsulfone, hexylsulfone, heptylsulfone or octylsulfone, 10 furthermore nonylsulfone, decylsulfone, undecylsulfone or dodecylsulfone, for example.

If R is an alkyl group wherein one or more CH2 groups are replaced by CH=CH-, this may be straight-chain or branched. It is preferably 15 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 pent4-enyl, hex-1-, 2-, 3-, 4- or hex-5 - nyl, inept-1-, 2-, 3-, 4-, 5 or hept-6-enyl, oct-1-, 2-, 3-, 4-, 5-, 6- or oct-7 - nyl, non-1-, 2-, 3-, 4-, 5-, 6-, 7- or non-8-enyl, dec-1-, 2-, 3-, 4-, 5-, 6-, 7-, 8- or dec9-enyl.

Especially preferred alkenyl groups are CCr1 E-alkenyl, C4-Cr3E alkenyl, C5-C'4-alkenyl, CC7-5-alkenyl and Cr6-alkenyl, in particular C2-C7-1 Ealkenyl, C4-C7-3E-alkenyl and Cs-C74-alkenyl.

Examples for particularly preferred alkenyl groups are vinyl, 25 1 Epropenyl, 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.

30 If R is an alkyl group, wherein one CH2 group is replaced by-O- and one by CO-, these radicals are preferably neighbouring. Accordingly these radicals together form a carbonyloxy group -CO-O- or an oxycarbonyl group -O-CO-.

Preferably this group R is straight-chain and has 2 to 6 C atoms.

( - 15 lt is accordingly preferably acetyloxy, propionyloxy, butyryloxy, pentanoyloxy, hexanoyloxy, acetyloxymethyl, propionyloxymethyl, butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl, 2propionyloxyethyl, 2-butyrylaxyethyl, 3-acetylaxypropyl, 5 3propionyloxypropyl, 4-acetylaxybutyl, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, methoxycarbonylmethyl, ethoxycarbonylmethyl, propoxycarbonylmethyl, butoxycarbonylmethyl, 2(methoxycarbonyl)ethyl, 2-(ethoxycarbonyl)ethyl, 2-(propoxy 10 carbonyl) ethyl, 3-(methoxycarbonyl)propyl, 3-(ethoxycarbonyl)propyl, 4(methoxycarbonylibutyl. If R is an aikyl group, wherein two or more CH2 groups are replaced by -O- and/or -COO-, it can be straight-chain or branched. It is 15 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, 6,6bis-carboxy hexyl, 7,7-bis-carboxy-heptyl, 8,8-bis-carboxy-octyl, 9,9-biscarboxy nonyl, 10,10-bis-carboxy-decyl, bis-(methoxycarbonyl)-methyl, 20 2,2-bis-(methoxycarbonylethyl, 3,3-bis-(methoxycarbonyl)-propyl, 4,4bis-(methoxycarbonylibutyl, 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 25 (ethoxycarbonyl)-butyl, 5,5-bis-(ethoxycarbonyl)-hexyl.

If R is an alkyl or alkenyl group that is monosubstituted by ON or CF3, it is preferably straighthain. The substitution by ON or CF3 can be in any desired position.

If R is 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 35 or Cl substituent can be in any desired position, but is preferably in an w-: position. Examples for especially preferred straight-chain groups

- 16 with a terminal F substituent are fluormethyl, 2-fluorethyl, 3fluorpropyl, 4-fluorbutyl, fluorpentyl, 6-fluorhexyl and 7-fluorheptyl. Other positions of F are, however, not excluded.

5 Halogen is preferably F or Cl.

R in formula I can be a polar or a non-polar group. In case of a polar group, it is selected from CN, SF5, halogen, OCH3, SON, CoR5, CoOR5 or a mono- oligo- or polyfluorinated alkyl or alkoxy group with 10 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, COC2Hs, COOCH3, COOC2H5, CF3, CHF2, CH2F, OCF3, OCHF2, OCH2F, C2F5 and OC2F5, in particular F. Cl, CN, CF3, OCHFz and OCF3. In case of a non-polar 15 group, it is preferably alkyl with up to 15 C atoms or alkoxy with 2 to 1 5 C atoms.

R in formula I can be an achiral or a chiral group. In case of a chiral group it is preferably selected of formula lil: -Q1-CH-Q

Q lil 25 wherein Q' is an alkylene or alkylene-oxy group with 1 to 9 C atoms or a single bond, 30 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-, -O-, S-, -NH-, -N(CH3, -CO-, -COO-, -OCO-, -OCO-O-,

35 -S-CO- or -CO-S- in such a manner that oxygen atoms are not linked directly to one another,

- 17 Q3 is F. Cl, Br, CN or an alkyl or alkoxy group as defined for Q2 but being different from Q2 5 In case Q' in formula lil is an alkylene- oxy group, the O atom is preferably adjacent to the chiral C atom.

Preferred chiral groups of formula lil are 2-alkyl, 2-alkoxy, 2methylalkyl, 2-methylalkoxy, 2-fluoroalkyl, 2-fluoroalkoxy, 2-(2-ethin)alkyl, 2-(2 10 ethin)-alkoxy, 1,1,1-trifluoro-2-alkyl and 1,1,1-trifluoro2-alkoxy.

Particularly preferred chiral groups are 2-butyl (=1-methylpropyl), 2 methylbutyl, 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2 propylpentyl, In particular 2-methylbutyl, 2-methylbutoxy, 2 15 methylpentoxy, 3methylpentoxy, 2-ethylhexoxy, 1-methylhexoxy, 2 octyloxy, 2-oxa-3methylbutyl, 3-oxa-methylpentyl, 4-methylhexyl, 2-hexyl, 2-octyl, 2-nonyl, 2-decyl, 2-dodecyl, 6-methoxyoctoxy, 6 methyloctoxy, 6-methyloctanoylaxy, 5-methylheptyloxycarbonyl, 2 methylbutyryloxy, 3-methylvaleroylaxy, 4methylhexanoyloxy, 2 20 chlorpropionyloxy, 2<hloro-3-methylbutyryloxy, 2chloro 4 methylvaleryloxy, 2-chloro-3-methylvaleryloxy, 2-methyl-3oxapentyl, 2-methyl-3-oxahexyl, 1-methoxypropyl-2-oxy, 1-ethoxypropyl-2oxy, 1-propoxypropyl-2-oxy, 1-butoxypropyl-2-oxy, 2-fluorooctyloxy, 2 fluorodecyloxy, 1,1,1-tnfluoro-2-oclyloxy, 1,1,1-trifluoro-2-octyl, 2 25 fluoromethyloctyloxy for example. Especially preferred are 2-hexyl, 2octyl, 2 octyoxy, 1,1, 1-tnfluoro-2-hexyl, 1,1, 1-trifluoro-2-octyl and 1, 1, 1-tnfluoro-2 octyloxy. In addition, compounds of formula I containing an achiral branched 30 group R 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), isopenlyl (=3-methylbutyl), isopropoxy, 2-methyl 35 propoxy and 3methylbutoxy.

- 18 The polymerisable or reactive group P is preferably selected from O < > CH2=CW'-COO, W HO-CH-, w2(CH2)k-O-, CH2=CW2 5 ( )k1-. CH3-CH=CH-O-, (CHz=CH)2CH-OCO-, (CH2=CH-CH2)2CH OCO-, (CH2=CH)2CH-O-, (CH2=CH-CH2)2N-, Ho-CW2W3-, HS CW2W3-, HW2N-, Ho-CW2W3-NH-, CH2=CW'-CO-NH-, CH2-CH (COO)k,Phe-(O)k2-, Phe-CH=CH-, HOOC-, OCN-, and W4W5\t\/6Si-, with W' being H. Cl, ON, phenyl or alkyl with 1 to 5 C-atoms, in 10 particular H. Cl or CH3, w2 and W3 being independently of each other H or alkyl with 1 to 5 Catoms, in particular methyl, ethyl or n propyl, W4, W5 and w6 being independently of each other Cl, oxaalkyl or oxacarbonylalkyl with 1 to 5 C-atoms, Phe being 1,4 phenylene and k' and k2 being independently of each other 0 or 1.

15: Especially preferably P is a vinyl group, an acrylate group, a methacrylate group, a propenyl ether group or an epoxy group, especially preferably an acrylate or a methacrylate group.

20 As for the spacer group Sp all groups can be used that are known for this purpose to those skilled in the art. The spacer group Sp is preferably a linear or branched alkylene group having 1 to 20 C atoms, in particular 1 to 12 C atoms, in which, in addition, one or more nonadjacent CH2 groups may be replaced by -O-, -S-, -NH-, 25 N(CH3)-,-CO-,-OCO-,-S-CO-,-O-COO-,-CO-S-,-CO-O-,

CH(halogen/, -C(halogen)2, -CH(CN>, -CH=CH- or -C-C-,or a siloxane group.

Typical spacer groups are for example -(CH2)p-, -(CH2CH2O)r-CH2CH2-, 30 CH2CH2-S-CH2CH2- or-CH2CH=NH-CH2CH2- or -(SiR R -O)p-, with p being an integer from 2 to 12, r being an integer from 1 to 3 and R and R having the meanings given in formula 1.

Preferred spacer groups are ethylene, propylene, butylene, 35 pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene,

- 19 methyleneoxybutylene, ethylene-thioethylene, ethylene-N-methyl-

iminoethylene, 1-methylalkylene, ethenylene, propenylene and butenylene for example.

5 Further preferred are compounds with one or two groups P-Sp-X wherein Sp and/or X is a single bond.

In case of compounds with two groups P-Sp-X, each of the two polymerisable groups P. the two spacer groups Sp, and the two 10 linkage groups X can be identical or different.

In another preferred embodiment of the invention the chiral compounds of formula I comprise at least one spacer group Sp that is a chiral group of formula IV: -Q'-CH-Q4

Q3 IV 20 wherein Q' and Q3 have the meanings given in formula lil, and Q4 is an alkylene or alkylene-oxy group with 1 to 10 C atoms or a 25 single bond, being different from Q'.

Particularly preferred compounds of formula I are those of the following formulae 30 (L),

PER 11

( - 20 (L)r P-Sp-X>R 12 5 (L)r P-Sp-XR 13 1 0 (L)r P-Sp-X SIR 14 (L)r (L) r! 15 - \ P-Sp-X _ oR 15 (L), (L)r 20 P-Sp-XCOO: = R 16 (L)r (L)r 25 P-Sp-Xó=COO6 R

17 (L)r (L)r P-Sp-XR 18 (L)r (L), P-Sp-X- OR 19

ll - 21 (L)r (L)r P-Sp-X:COOR 110 5 (L)r (L), P-SXCOOóR 111 1 0 (L)r (L)r P-Sp-X OR 112 (L)r (L)r P-Sp-XR 113 (L)r (L)r 20 P-Sp-X: COO≤óR I 14 (L) r (L)r 25 P-Sp-XCOOR 115 (L), (L)r P-SX j; ) R 116 (L)r (L)r P-Sp-Xó=N/ R I 17

- 22 (L)r (L)r P-Sp-X - COO SIR 118 (L)r (L)r P-Sp-X>COO6R 11 9 1 0 (L)r (L)r P-Sp-X - / WAR 120 15 wherein P. Sp, X, R. L and r have the meanings given above.

Particularly preferred are compounds of the above formulae wherein R is PSp-X, furthermore those, wherein R is H or alkyl with 1 to 8 C-

atoms. The compounds of formula I can be synthesized according to or in analogy to methods which are known per se and which are described in standard works of organic chemistry such as, for example, Houben-Weyl, Methoden der organischen Chemie, Thieme-Verlag, 25 Stuttgart. Some specific methods of preparation can be taken from the examples.

The compounds of formula I can be used in a liquid crystal mixture for displays like, for example, TN or STN displays, active matrix 30 displays, displays of the IPS (in plane switching) or VA (vertically aligned) mode like VAN (vertically aligned nematic) or VAC (vertically aligned cholesteric), displays of the ECB (electrically controlled birefringence), DAP (deformation of aligned phases), CSH (colour super homeotropic) or ASM (axially symmetric microcell) mode, 35 phase-change, guest-host, flexoelectric, ferroelectric displays, bistable nematic and cholesteric displays like PSCT (polymer

- 23 stabilized cholesteric texture), or PDLC, polymer gel or polymer network displays.

In particular, the polymerisable compounds of formula I and mixtures 5 comprising them are useful for liquid crystal displays that comprise a polymer or polymer network component for the purpose of assisting alignment, mesophase stability and/or electrooptical property improvement, in particular to achieve faster response times and/or lower threshold voltages, Or in order to create a multidomain 10 structure to achieve improved contrast at wide viewing angles. Such displays are for example of the TN, STN, ECB, VA, IPS, multidomain or hybrid mode, and are described for example in US 5,189,540, US 6,177,972, EP 0 903 392, and Hasebe et al., Jpn.J.Appl.Phys.1994, 33, 6245.

Furthermore, the compounds of formula I are suitable as polymerisable component in active broadband polymer stabilized liquid crystal displays as described for example in H. Guillard and P. Sixou, Liq.C'yst. (2001) 28(6), 933, the entire disclosure of which is

20 incorporated into this application by reference. These dispays comprise an active cholesteric layer with a broadened reflection wavelength band that is switchable between a planar reflective, a scattering and a homeotropic transparent state.

25 The compounds of formula I are also suitable as a polymer component in polymer stabilised displays, such as bistable PSCT (polymer stabilized cholesteric texture) displays, or PDLC or polymer gel displays of the scattering type. Anisotropic polymer gels and displays comprising them are disclosed for example in DE 195 04 30 224, GB 2 279 659, WO 93/22397, US 5,538,768, US 5,543,075 and EP 0 451 905

Thus, another object of the invention is a liquid crystal mixture, in particular a nematic liquid crystal mixture, comprising at least one 35 compound of formula 1.

- 24 Yet another object of the invention is a liquid crystal display comprising a liquid crystal medium containing at least one compound of formula 1.

5 For the applications described above the liquid crystal mixture preferably contains at least one compound of formula 1, and a nematic host mixture comprising one or more nematic or nematogenic compounds.

10 Preferably the liquid crystal mixture consists of 2 to 25, preferably 3 to 15 compounds, at least one of which is a compound of fonnula 1.

The other compounds, forming the nematic host mixture, are preferably low molecular weight liquid crystal compounds selected from nematic or nematogenic substances, for example from the 15 known classes of the azoxybenzenes, benzylidene-anilines, biphenyls, terphenyls, phenyl or cyclohexyl benzoates, phenyl or cyclohexyl esters of cyclohehexanecarboxylic acid, phenyl or cyclohexyl esters of cyclohexylbenzoic acid, phenyl or cyclohexyl esters of cyclohexylcyclohexanecarboxylic acid, cyclohexylphenyl 20 esters of benzoic acid, of cyclohexanecarboxylic acid and of cyclo hexylcyclohexanecarboxylic acid, phenylcyclohexanes, cyclohexyl biphenyls, phenylcyclohexylcyclohexanes, cyclohexylcyclohexanes, cyclohexylcyclohexenes, cyclohexylcyclohexylcyclohexenes, 1,4-bis cyclohexylbenzenes, 4,4'-bis-cyclohexylbiphenyls, phenyl- or cyclo 25 hexylpyrimidines, phenyl- or cyclohexylpyridines, phenyl- or cyclo hexylpyridazines, phenyl- or cyclohexyidioxanes, phenyl- or cyclo hexyl-1, 3-dithianes, 1,2-diphenyl-ethanes, 1,2-dicyclohexylethanes, 1-phenyl-2cyclohexylethanes, 1-cyclohexyl-2-(4-phenylcyclohexyl) ethanes, 1cyclohexy1-2-biphenyl-ethanes, 1-phenyl2-cyclohexyl 30 phenylethanes, optionally halogenated stilbenes, benzyl phenyl ether, tolanes, substituted cinnamic acids and further classes of nematic or nematogenic substances. The 1,4-phenylene groups in these compounds may also be laterally mono- or difluorinated.

35 The liquid crystal mixture of this preferred embodiment is based on the achiral compounds of this type.

- 25 The most important compounds that are possible as components of these liquid crystal mixtures can be characterized by the following formula R'-L'-G'-E-R"

wherein L' and E, which may be identical or different, are in each case, independently from one another, a bivalent radical selected from the 10 group formed by -Phe-, -Cyc-, -Phe-Phe-, -Phe-Cyc-, -Cyc-Cy>, -Pyr-, Dim, -B-Phe- and -B-Cyc- and their mirror images, where Phe is unsubstituted or fluorine-substituted 1,4-phenylene, Cyc is trans 1,4cydohexylene or 1,4-cyclohexenylene, Pyr is pyrimidin+2,dlyl or pyndin 2, Ethyl, Dio is 1, 3ioxane-2, 5iyl and B is 2-(trans-1, 4-..= 15 cyclohexyl)ethyl, pyrimidine-2,dlyl, pyridine-2,diyl or 1,3ioxane 2,5dlyl. G' in these compounds is selected from the following bivalent groups -CH=CH-, -N(0)N-, -CH=CY-, -CH=N(0)-, -C_C-, -CH2-CH2-,

20 -CO-O-, -CH2-O-, -CO-S-, -CH=S-, -CH-N-, -COO-Phe-COO- or a single bond, with Y being halogen, preferably chlorine, or -CN.

R' and R" are, in each case, independently of one another, alkyl, alkenyl, alkoxy, alkenyloxy, alkanoyloxy, alkoxycarbonyl or 25 alkoxycarbonyloxy with 1 to 18, preferably 3 to 12 C atoms, or alternatively one of R' and R" is F. CF3, OCF3, Cl, NCS or CN.

In most of these compounds R' and R" are, in each case, independently of each another, alkyl, alkenyl or alkoxy with different 30 chain lengths, wherein the sum of C atoms in the compounds of nematic media is generally between 2 and 9, preferably beDueen 2 and 7.

Many of these compounds or mixtures thereof are commercially available. All of these compounds are either known or can be 35 prepared by methods which are known per se, as described in the literature (for example in the standard works such as Houben-Weyl,

- 26 Methoden der Organischen Chemie [Methods of Organic Chemistry], Georg-Thieme-Verlag, Stuttgart), to be precise under reaction conditions which are known and suitable for said reactions. Use may also be made here of variants which are known per se, but are not 5 mentioned here.

The compounds of formula I and polymerisable liquid crystal mixtures comprising them are further useful for the preparation of anisotropic polymer films or coatings.

For the preparation of anisotropic polymer gels or polymer films, the liquid crystal mixture should comprise at least one polymerisable compound, which can be a compound of formula I or an additional polymerisable mesogenic or liquid crystalline compound.

Examples of suitable polymerisable mesogenic compounds that can be used as comonomers together with the compounds of formula I in a polymerisable liquid crystal mixture, are disclosed for example in WO 93/22397; EP 0, 261,712; DE 195,04,224; WO 95/22586 and 20 WO 97/00600. The compounds disclosed in these documents, however, are to be regarded merely as examples that shall not limit the scope of this invention.

Preferably the polymerisable liquid crystal mixture comprises at least 25 one polymerisable mesogenic compound having one polymerisable functional group and at least one polymerisable mesogenic compound having two or more polymerisable functional groups.

Examples of especially useful monoreactive chiral and achiral 30 polymerisable mesogenic compounds are shown in the following lists which should, however, be taken only as illustrative and is in no way intended to restrict, but instead to explain the present invention: 35 P- (CH2)XO COO Y a)

- 27 P (CH2)xO COO <3óY (Vb) 5 P-(CH2)xO COO R (Vc) P-(CH2)xO COO R (Vd) P-(CH2)xO CH=CH-COO R (Ve) 15 CH2=CHCOO(CH2):. 0}R

20 P-(CH2)xO R (F) (F) (F) (V9)

P-(CH2)x j3 COO CH2CH(cH3)c2Hs (Vh) 25 L' P-(CH2)XO COO COO CH2CH(CH3) C2H5 (Vi) 30 P-(CH2)xo j3COO-Ter (Vk) P-(CH2)xO COO-Chol (Vm)

f - 28 P]CH2)X0 /3 COO; - An) P(CH2)xO COOL OCO O(CH2)yP (Via) 10 P(CH2) xO CHzCH2 CH2CH2 O(CH2)yP l b) L' LZ 15 óco26O2Cóo (Vlc) P(CH2)xO CH=CH=: 20 OOCCH=CH o(CH2)yP (Vld) P(CH7),0 of O(CH2)yP (\/le) wherein P has one of the meanings of formula I and its preferred 30 meanings as mentioned above, x and y are identical or different integers from 1 to 12, A and D are 1,4-phenylene or 1,4 cyclohexylene, v is 0 or 1, Y is a polar group, R is a non-polar alkyl or alkoxy group, Ter is a terpenoid radical like e.g. menthyl, Chol is a cholesterol group, and L' and L2 are each independently H. F. Cl, 35 OH, CN, NO2 or optionally alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl with 1 to 7 C atoms.

- - 29 The term 'polar group' in this connection means a group selected from F. Cl, ON, NO2, OH, OCH3, OCN, SON, an optionally fluorinated carbonyl or carboxyl group with up to 4 C atoms or a mono;oligo- or 5 polyQuorinated alkyl or alkoxy group with 1 to 4 C atoms. The term 'non polar group' means an alkyl group with 1 or more, preferably 1 to 12 C atoms or an alkoxy group with 2 or more, preferably 2 to 12 C atoms.

The polymerisable liquid crystal mixtures according to the present 10 invention may also comprise one or more non-reactive chiral dopants in addition or alternatively to chiral polymerisable mesogenic compounds. Typically used chiral dopants are e.g. the commercially available R or S 811, R or S 101 1, R or S 2011 or CB 15 (from Merck KGaA, Darmstadt, Germany).

Especially preferred are chiral dopants with a high helical twisting power (HTP), in particular dopants comprising a sorbitol group as described in WO 98/00428, dopants comprising a hydrobenzoin group as described in GB 2,328,207, chiral binaphthyl derivatives as described 20 in VVO 02/94805, chiral binaphthol acetal derivatives as described in WO 02/34739, chiral TADDOL derivatives as described in WO 02/06265, and chiral compounds having at least one fluorinated linkage group and a terminal or central chiral group as described in WO 02/06196 and WO 02/06195.

To prepare anisotropic polymer films, the polymerisable liquid crystal is preferably coated onto a substrate, aligned and polymerized in situ, for example by exposure to heat or actinic radiation, to fix the orientation of the liquid crystal molecules. Alignment and curing are 30 carried out in the liquid crystalline phase of the mixture.

The substrate is for example a glass or quartz sheet or a plastic film or sheet, and can be removed after polymerization or not. Suitable plastic substrates are for example polyethyleneterephthalate (PET), 35 of polyvinylalcohol (PVA), polycarbonate (PC) or triacetylcellulose (TAC). The polymerisable chiral LC material may also be dissolved

- 30 or dispersed in an organic solvent that is evaporated before or during polymerization. Alignment of the liquid crystal material can be achieved for example 5 by treatment of the substrate onto which the material is coated, by shearing the material during or after coating, by application of a magnetic or electric field to the coated material, or by the addition of

surface-active compounds to the liquid crystal material. Reviews of alignment techniques are given for example by 1. Sage in 10 '1hermotropic Liquid Crystals", edited by G. W. Gray, John Wiley & Sons, 1987, pages 7577, and by T. Uchida and H. Seki in "Liquid Crystals - Applications and Uses Vol. 3", edited by B. Bahadur, World Scientific Publishing, Singapore 1992, pages 1-63. A review of alignment materials and techniques is given by J. Cognard, Mol. 15 Cryst. Liq. Cryst. 78, Supplement 1 (1981), pages 1-77.

Polymerisation takes place by exposure to heat or actinic radiation.

Actinic radiation means irradiation with light, like UV light, IR light or visible light, irradiation with X-rays or gamma rays or irradiation with 20 high energy particles, such as ions or electrons. Preferably polymerization is carried out by UV irradiation at a non-absorbing wavelength. As a source for actinic radiation for example a single UV lamp or a set of UV lamps can be used. When using a high lamp power the curing time can be reduced. Another possible source for 25 actinic radiation is a laser, like e.g. a UV laser, an IR laser or a visible laser. Polymerisation is carried out in the presence of an initiator absorbing at the wavelength of the actinic radiation. For example, when 30 polymerizing by means of UV light, a photoinitiator can be used that decomposes under UV irradiation to produce free radicals or ions that start the polymerization reaction. When curing polymerisable mesogens with acrylate or methacrylate groups, preferably a radical photoinitiator is used, when curing polymerisable mesogens vinyl and 35 epoxide groups, preferably a cationic photoinitiator is used. It is also possible to use a polymerization initiator that decomposes when

- 31 heated to produce free radicals or ions that start the polymerization.

As a photoinitiator for radical polymerization for example the commercially available Irgacure A) 651, Irgacure 49 184, Darocure 1173 or Darocure 4205 (all from Ciba Geigy AG) can be used, whereas in case of 5 cationic photopolymensation the commercially available UVI 6974 (Union Carbide) can be used.

The polymensable material can additionally comprise one or more other suitable components such as, for example, catalysts, sensitizers, 10 stabilizers, inhibitors, antioxidants, chain-transfer agents, co- reacting monomers, surface-active compounds, lubricating agents, wetting agents, dispersing agents, hydrophobing agents, adhesive agents, flow improvers, defoaming agents, deaerators, diluents, reactive diluents, auxiliaries, colourants, dyes or pigments.

Compounds of formula I comprising a chiral group are suitable as chiral dopants. Furthermore, the compounds of formula I are suitable as comonomers 20 for liquid crystal materials with semiconductor or charge carrier properties, which can be used in electronic devices like for example field

effect transistors (PET) as components of integrated circuitry, as thin film transistors in flat panel display applications or for Radio Frequency Identification (RFID) tags, or semiconducting components for organic 25 light emitting diode (OLED) applications such as electroluminescent displays or backlights of e.g. liquid crystal displays, photovoltaic or sensor devices, photoconductors, or electrophotographic applications like electrophotographic recording devices.

30 For example, semiconductors comprising polymerisable liquid crystal compounds are disclosed in WO 00t79617, JP-A-2000-347432, JP--

1 1-209761, Sirringhaus et al., Appl. Phys. Lett., 77(3) (2000) 406408,, and Grell et al., J. Korean Phys. Soc. 2000, 36(6), 331.

Electroluminescent devices using liquid crystal materials are described 35 for example in WO 95/17018 and WO 95/04306. Organic

- 32 photoconductors with liquid crystal properties are described for example in EP 0 563 768 and EP 0 527 376.

Without further elaboration, it is believed that one skilled in the art 5 can, using the preceding description, utilize the present invention to

its fullest extent. The following examples are, therefore, to be construed as merely illustrative and not limitative of the remainder of the disclosure in any way whatsoever.

10 In the foregoing and in the following examples, unless otherwise indicated, all temperatures are set forth uncorrected in degrees Celsius and all parts and percentages are by weight.

The following abbreviations are used to illustrate the liquid crystalline 15 phase behaviour of the compounds: K = crystalline; N = nematic; S = smectic; Ch = cholesteric; I = isotropic. The numbers between the symbols indicate the phase transition temperatures in C. Furthermore, mp. is the melting point, An is the optical anisotropy measured at 20 C and 589 nm, ME iS the dielectric anisotropy at 20 20 C and 1 kHz.

ExamDIe 1 Compound (1) is prepared according to the following reaction scheme / - + NaNO2/ HCI /=\:\ H2N <0> ZnCI2 -SiMe3 30 Pd(PPh3)2Cl2' Cul, NEt3 /=\ NaOH/ MeOH /=\ AH ' O'=SiMe3

p - 33 H2NóBr + TO NaNO21 HCI B OH HOtCH,OH + NE\, HOOt | DCC, DEEP 1 0 BrOO 15 H Pd(PPh3)2C112/ CUI/ NEt3 20 O Of (1) 25 Example 2

Compound (2) is prepared according to the following reaction scheme Br + 13Br 'BuLUZnCI2/Pd(PPh3)4 i/=\ 30 N // Br Cul/ Pd(PPh3)2Cl2/ NEt3 _ Si(Me) 3

pU. - 34 -

/=\ / NaOH/ MeOH /=\ /=\ ) - _ H /iSi(Me)3 MOTH 5 1 Cul/ Pd(PPh3)2C12/ NEt3 :{ OH

IBM OH

Butanone/ K2CO3 5:_ Of Cl to 20 1 NEt3 0; 25 (2)

ExamoIe 3 3 Compound (3) is prepared according to the following reaction scheme

- 35 Bró:_SiMe3 (SiMe3 5 1 War Pd(PPh3)2/ Mel ZnBrz NaOH/ MeOH \ N SiMe lóOH Pd(PPh3)2Cl2I Cut/ NEt3 ma_ 20: 25 CICH2CH2CO2(CFJ2)o: SOCI2/DCM, clCH2CH2Co2(CH2)eoC' i| DCC/DMAP

- 3(i ClCH2CH2Co2(CH2)6O} _-

5 | NEt3/ DCM 40 0 O(CH2)BO Wy _ 10 (a) ExamDIe 4 15 Compound (4) is prepared according to the following reaction scheme HOW Pd(PPh,)2CI21 Cul/ NEt3 SiMe3 20 1 sr' < | Butanone/ K2CO3 25 NO oS'Me3 I NaOH/ MeOH o 0 on=

pi - 37 Br3 - P + HO óO(CH2)6OCoCH=CH2 | DCC/ DMAP

Bra O O(CH2)eOCOCH=CH2 a} I Pd(PPh3)2C12/Cul/ NEt3 1 5 CH2=CHCOO(CH2)3O

OóO(CHz)60COCH=CH2 (4)

Claims (11)

- 38 Claims

1. A polymerizable compound of formula I s P-SX-(A -Z)m1Cec(z -A)m2 R wherein: P is a polymerizable group, Sp is a spacer group or a single bond, /0 X is-O-,-S-,-CO-,-COO-,-OCO-,-HC CH-,-OCO-O-, -S-CO-, -CO-S-, CO-NR -, -NR -CO-, -OCH2-, -CH2O-,

5 -SCH2-, -CH2S-, -CH= CM-COO-, -OOC-CH= CH-, -CH2CH2

or a single bond, Z and Z2 are each independently-COO-, -OCO-, -OCH2-, CH2O-, -SCHz-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCFz-, -CH2CH2-, 20 CF2CH2-, -CH2CF2-, -CF2CF2-, -CH=CH-, -CF= CH-,

-CH=CF-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH-,

-C_C- or a single bond, A and A2 are each independently an aliphatic or aromatic carbocyclic or 2s heterocyclic group with up to 16 C atoms that may also comprise fused rings and may be unsubstituted, mono- or polysubstituted with L, L is, C1, Br, I, CN, NO2 or alkyl, alkoxy, alkylcarbonyl, 30 alkoxyearbonyl or alkylcarbonyloxy with 1 to 7 C atoms, wherein one or more H atoms may be substituted by F or C1,

f - 3' ml and m2 are each independently 0, 1, 2, 3, 4 or 5, with ml + m2 being 1, 2, 3, 4 or 5, R is H. F. Cl, Br, I, CN, SCN, SFs, straight chain or branched s alkyl with up to 25 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-, -NR -, -SiR R -, -CO-, -COO-, -OCO-, -OCO-O-, 70 -S-CO-, -CO-S-, -SO2-, -SO-O-, -O-SO-, -CH=CHor -C_C in such a manner that O and/or S atoms are not linked directly to one another, or is P-Sp-X, and R and R are independently of each other H or alkyl with 1 to 4 C 15 atoms, wherein the compounds contain at lease one heterocyclic group A' or A2.

2. A polymerizable compound as claimed in claim 1, wherein ml is 1 or 2 20 and m2 is 1 or 2.

3. A polymerizable compound as claimed in claim 1 or 2, wherein at least one group A1 or A2 in an a-position to the acetylene group is a heteroaromatic group.

4. A polymerizable compound as claimed in any of the precedng claims, wherein A1 and A2 are selected from furane-2,5-diyl, thiophene-2,5-diyl, pyrrol-2,5-diyl, 1,4-phenylene, pyridine-2,5-diyl, pyrimidine-2,5-diyl, naphthalene-2,6-diyl, 1,2,3,4-tetrahydro-napthalene-2,6-diyl, indane-2,5 o diyl, and 1,4-cyclohexylene in which, in addition, one or two non adjacent CH2 groups ate optionally replaced by O and/or S. it being possible for all these groups to be unsubstituted, mono- or polysubstituted by L as defined in claim 1.

( - 40

5. A polymerizable compound as claimed in any of the preceding claims, wherein -(A,-Z')ml- and -(Z2-A2)m2- are, independently of each other, selected from the following formulae and their mirror images: lla lo i,> llb (L)r llc 75 \J :3 1 Id 20 lo/ 3 lie (L)r (L)r 25 11f (L)r (L)r 30 SCOOT 119

- 41 (L)r lih (L)r _>COO Hi (L), 10 in_ lik (L), _>COO llm (L)r Nit Iln (L)r COO) Ho 25 (L)r llp (L)r 30 /= N

COO: llq

! - 42

(L)r (jar (L)r 5 NO lls (L)r to fit wherein L is as defined in claim 1, and r is 0, 1, 2, 3 or 4.

15

6. A polymerizable compound as claimed in any of the preceding claims, selected from the following formulae: (L)r P-Sp-XR I 1 (L)r P-Sp-X(\ OR 12 25 (tar P-Sp-XR 13 (a), P-Sp-XFt 14

( - 43 (L)r (L)r P-Sp-Xt =R 15 s (L)r (L)r P-Sp-X:COO - R 16 (L)r (L)r PSXCOO: R 17

(L)r (L), Is P-Sp-XR 18 (L)r (L)r p Sp X4R 19 (L)r (L)r P-Sp-X: COOR 110 25 (L)r (L)r P-Sp-X ≥: COO4R 111 (L)r (L)r 30 P-Sp-X = OR 112

- 44 (L)r (L)r P-SX WAR 113

s (L)r (L)r P-SX - COOR I 14

(L)r (L)r 10 P-Sp-XCOO6R 115 (L)r (L)r P-SX{ R 116

(L)r (L)r P-Sp-X N>R I 17 (L), (L)r P-Sp-X >COO OR 118 As (L)r (L)r P-SX z - COO^R 119 (L)r (L)r P-SX - / WAR 120

- 45 wherein P. Sp, X, R. L and r have the meanings given above.

7. A polymerizable compound substantially as hereinbefore described in the foregoing examples.

8. A polymerizable liquid crystal mixture comprising at least one compound as claimed in any of the preceding claims.

9. An anisotropic polymer or polymer film obtained from a polymerizable 10 liquid crystal mixture as claimed in claim 8.

10. Use of a polymerizable compound as claimed in any one of claims 1 to 7, a polymerizable liquid crystal mixture as claimed in claim 8, or an anisotropic polymer or polymer film as claimed in claim 9, in optical 15 films, polarizers, compensators, beam splitters, reflective films, alignment layers, colour filters, holographic elements, hot stamping foils, coloured images, decorative or security markings, liquid crystal pigments, adhesives, synthetic resins with anisotropic mechanical properties, cosmetics, diagnostics, nonlinear optics, optical information storage, as 20 chiral dopants, in electronic devices like for example field effect

transistors (FEI) as components of integrated circuitry, as thin film transistors in flat panel display applications or for Radio Frequency Identification (RFID) tags, or in semiconducting components for organic light emitting diode (OLED) applications such as electroluminescent 25 displays or backlights of e.g. liquid crystal displays, for photovoltaic or sensor devices, as electrode materials in batteries, as photoconductots, or for electrophotographic applications like electrophotographic recording.

11. A liquid crystal display comprising in its active layer at least one 30 compound as claimed in any one of claims 1 to 7, a mixture as claimed in claim 8 or a polymer or polymer film as claimed in claim 9.