GB2337753A - Mesogenic 1,3-dioxanes, & thia analogues thereof, having at least one polymerizable terminus - Google Patents

Abstract

There are disclosed polymerizable mesogenic compounds of formula I wherein P, Sp, X, n, A, A<SP>1</SP>, A<SP>2</SP>, A<SP>3</SP>, Z<SP>1</SP>, Z<SP>2</SP>, Z<SP>3</SP>, a, b and R have the meanings given in claim 1, polymerizable liquid crystalline compositions comprising at least one compound of formula 1, the use of these compounds and compositions for the preparation of linear or crosslinked liquid crystalline polymers and polymer films, and the use of these compounds, compositions and polymers in liquid crystal displays, active and passive optical elements, adhesives, synthetic resins with anisotropic mechanical properties, cosmetics, diagnostics, liquid crystal pigments, for decorative and security applications, in nonlinear optics, optical information storage or as chiral dopants. In Formula I: X' and X" are independently of each other -O- or -S-; P is CH 2 =CW-COO-, WCH=CH-O-, or CH 2 =CH-Phenyl-(O) k - with W being H, CH 3 or Cl and k being 0 or 1; Sp is a spacer group having 1 to 20 C atoms; X is -O-, -S-, -CO-, -COO-, OCO-, -CO-NH-, -NH-CO-, -CH 2 CH 2 -, -OCH 2 -, -CH 2 O-. -SCH 2 -, -CH 2 S-, -CH=CH-, -CH=CH-COO-, -OCO-CH=CH-, -C#C- or a single bond; n is 0 or 1; Z<SP>1</SP> is -COO-, -OCO-, -CH 2 CH 2 -, -OCH 2 -, -CH 2 O-, -OCH 2 -O-, -CH=CH-, -CH=CH-COO-, -OCO-CH=CH- or -C#C-; Z<SP>2</SP> and Z<SP>3</SP> are each independently -COO-, -OCO-, -CH 2 CH 2 -. -OCH 2 -, -CH 2 O-, -CH=CH-, -CH=CH-COO-, -OCO-CH=CH-, -C#C-, or a single bond; (57) cont A<SP>1</SP>, A<SP>2</SP> and A<SP>3</SP> are each independently 1,4-phenylene (in which, in addition, one or more CH groups may be replaced by N), 1,4-cyclohexylene (in which, in addition, one or two non-adjacent CH 2 groups may be replaced by O and/or S), 1,4-cyclohexenylene, 1.4-bicyclo(2,2,2)octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, or 1,2,3,4-tetrahydro-naphthalene-2,6-diyl, it being possible for all these groups to be unsubstituted, mono- or polysubstituted with halogen, cyano or nitro groups or alkyl; alkoxy or alkanoyl groups having 1 to 7 C atoms wherein one or more H atoms may be substituted by F or Cl; a and b are each independently n, 1 or 2; and R is H, CN, halogen or a straight-chain or branched alkyl radical with up to 25 C atoms which may be unsubstituted, mono- or polysubstituted by halogen or CN, it being also possible for one or more non-adjacent CH 2 groups to be replaced, in each case independently from one another, by -O-, -S-, -NH-, -N(CH 3 )-, -CO-, -COO-, -OCO-, -OCO-O-, -S-, CO-, -CO-S- or -C#C- in such a manner that oxygen atoms are not linked directly to one another, or alternatively R is denoting P-(Sp-X) n -.

Description

- -1 - Polymerizable Mesogenic Compounds The invention relates to

polymerizable mesogenic compounds of formula 1 P-(SP-X)jAl- (Z2-A')a-Z 1 (:)- (Z-A 3)b-R 2337753 1 wherein 0 P is CH2=CW-COO-, WCH=CH-0-, WHC-CHor CH2=CHPhenyl-(0)k- with W being H, CH3 or Cl and k being 0 or 1, is a spacer group having 1 to 20 C atoms, is -0-, -S-, -CO-, -COO-, -OCO-, -CO-NH-, -NH-CO-, -CH2CH2-, -OCH2-, - CH20-, -SCH2-, -CH2S-, -CH=CH-, -CH=CH-COO-, OCO-CH=CH-, -C=-C- or a single bond, n is 0 or 1, is -COO-, -OCO-, -CH2CH2-, -OCH2-, -CH20-, -OCH2-0-, -CH=CH-, -CH=CH-COO-, -OCO-CH=CH- or -C=-C-, Z2 and Z3 are each independently -COO-, -OCO-, -CH2CH2-, -OCH2-, -CH20-, -CH=CH-, -CH=CH-COO-, -OCO-CH=CH-, -C-=C-, or a single bond, A 1, A 2 and A 3 are each independently 1,4-phenylene in which, in addition, one or more CH groups may be replaced by N, 1,4cyclohexyiene in which, in addition, one or two non-adjacent CH2 groups may be replaced by 0 andlor S, 1,4 cyclohexenylene, 1,4-bicyclo(2,2,2)octylene, pip"eridine-1,4-diyi, naphthalene-2,6-diyi, decahydronaphthalene-2,6-diyi, or 1,2,3,4-tetrahydro-naphthalene-2,6-diyl, it being possible for all these groups to be unsubstituted, mono- or polysubstituted with halogen, cyano or nitro groups or alkyl, aikoxy or alkanoyl groups having 1 to 7 C atoms wherein one or more H atoms may be substituted by F or Cl, a and b are each independently 0, 1 or 2, xl XY is or -()- XY _Cle A X' and X' are independently of each other -0- or -S-, and R is H, CN, halogen or a straight-chain or branched alkyl radical with up to 25 C atoms which may be unsubstituted, mono- or polysubstituted by halogen 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 -0, -S-, -NH-, -N(CH3)-, CO-, -COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S- or -C=C- in such a manner that oxygen atoms are not linked directly to one another, or alternatively R is denoting P-(SP-X)n-- The invention also relates to a polymerizable liquid crystalline composition comprising at least one polymerizable mesogenic compound of formula 1, and to the use of the inventive mesogenic compounds and compositions for the preparation of linear or crosslinked liquid crystalline polymers, in particular for the preparation of oriented films of linear or crosslinked liquid crystalline polymers.

The invention further relates to the use of inventive compounds, compositions and polymers in liquid crystal displays, such as STN, TN, AMID-TN, temperature compensation, guest-host, phase change or surface stabilized or polymer stabilized cholesteric texture (SSCT, PSCT) displays, in active and passive optical elements like polarizers, compensators, alignment layers, colour filters or holographic elements, in adhesives, synthetic resins with anisotropic mechanical properties, cosmetics, diagnostics, liquid crystal pigments, for decorative and security applications, in nonlinear optics, optical information storage or as chiral dopants.

Polymerizable mesogenic compounds, which are also known as reactive mesogenic compounds, have been described in prior art for various purposes. For example, they can be polymerized in situ whilst being macroscopically oriented in the liquid crystalline state to give anisotropic linear or crosslinked polymers or polymer films with uniform orientation of high quality. These films can be used for example as optical elements like broad band cholesteric polarizers (see EP 0,606, 940) or polarization filters (EP 0,397,263).

The WO 93122397, DE 195,04,224 and WO 97134862 for example disclose polymerizable mesogenic compounds with mesogenic cores of various structures.

The polymerizable mesogenic compounds described in prior art, however, often exhibit liquid crystalline phases only in a small temperature range or do not show mesophase behaviour at all.

Furthermore, they often exhibit high melting points, which is in particular disadvantageous for the preparation of highly oriented anisotropic polymers, since the polymerization has then to be carried out at high temperatures. Another drawback for specific applications is that prior art compounds often exhibit high values of the birefringence.

Thus, there is still a demand for polymerizable mesogenic compounds with a low melting point and a low value of the birefringence.

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

It was an aim of the invention to provide new polymerizable mesogenic compounds with advantageous properties, thus extending the pool of reactive liquid crystal compounds available 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 now found that these aims can be achieved by providing polymerizable mesogenic compounds of formula 1.

The terms polymerizable mesogenic compound or polymerizable liquid crystalline compound as used in the foregoing and the following comprise compounds with a rod-shaped, board-shaped or disk-shaped mesogenic group, i.e. a group with the ability to induce mesophase behaviour in a compound comprising said group. These compounds do not necessarily have to exhibit mesophase behaviour by themselves. It is also possible that these compounds show mesophase behaviour only in mixtures with other compounds or when the polymerizable mesogenic compounds or the mixtures comprising them are polymerized.

Thus, one object of the invention is a polymerizable mesogenic compound of formula 1 P-(SP-X)n-A 1 - (Z 2 -A 2).-Z 1 -(:)_ (f-A')b-R 1 wherein 0 P is C1-12=CW-CO0-, WCH=CH-0-, W1-IC-CH- or C1-12=CHPhenyl-(0)k- with W being H, CH3 or Cl and k being 0 or 1, Sp is a spacer group having 1 to 20 C atoms, X is -0-, -S-, -CO-, -COO-, -OCO-, -CO-NH-, -NH-CO-, -CH2CH2-, -OCH2-, -CH20-, -SCH2-, -CH2S-, -CH=CH-, -CH=CH-COO-, OCO-CH=Cl-1-, -C=-Cor a single bond, n is 0 or 1, Z1 is -COO-, -OCO-, -CH2CH2-, -OCH2-, -CH20-, -OCH2-0-, -CH=CH-, -CH=CH- COO-, -OCO-CH=CH- or -C=-C-, Z2 and Z3 are each independently -COO-, -OCO-, -CH2CH2-, -OCH2-, -CH20-, - CH=CH-, -CH=CH-COO-, -OCO-CH=CH-, -C=-C-, or a single bond, A', A 2 and A 3 are each independently 1,4-phenylene in which, in addition, one or more CH groups may be replaced by N, 1,4cyclohexylene in which, in addition, one or two non-adjacent CH2 groups may be replaced by 0 andlor S, 1,4cyclohexenylene, 1,4-bicycio(2,2,2)octylene, piperidine-1, 4-diyi, naphthalene-2,6-diyi, decahydronaphthalene-2,6-diyi, or 1,2,3,4tetrahydro-naphthalene-2,6-diyi, it being possible for all these groups to be unsubstituted, mono- or polysubstituted with halogen, cyano or nitro groups or alkyl, alkoxy or alkanoyl groups having 1 to 7 C atoms wherein one or more H atoms may be substituted by F or Cl, a and b are each independently 0, 1 or 2, X _G)_ is -x,y or xl _CXW p X' and X' are independently of each other -0- or -S-, and R is H, CN, halogen or a straight-chain or branched alkyl radical with up to 25 C atoms which may be unsubstituted, mono- or polysubstituted by halogen 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 -0- , -S-, -NH-, -N(CH3)-, C0-, -coo-, -OC0-, -OCO-0-, -S-CO-, -CO-S- or -C=- C- in such a manner that oxygen atoms are not linked directly to one another, or alternatively R is denoting P-(Sp-X),-.

Particularly preferred are polymerizable mesogenic compounds selected of the following formulae 0- P-(Sp-X),-A 1 - (Z 2 -A 2)a-z 1 -- (ZA')b-R 0 0 P-(Sp-x)n-A 1 - (Z 2 -A 2)a-z i-C _ (Z'_Abb-R 0 la lb 1 2 wherein P, Sp, X, n, A ' A ' A', Z1, Z2, Z3, a, b and R have the meanings given in formula 1, in parflucular those wherein Z1 is -COOor - OCO-.

Further preferred are compounds of formula 1 wherein Z' is -COO- or -OCO-, b is 0, a is 0 and A' is 1,4-phenylene, R has one of the meanings given for P-(Sp-X),-, R is halogen, cyano or an optionally fluorinated achiral or chiral alkyl or aikoxy group with 1 to 15 C atoms, n is 1 and Sp is alkylene with 1 to 15 C atoms.

Of the polymerizable mesogenic compounds of formula 1 especially preferred are those wherein -A' _(Z2 -A 2)a- and -(A 3_Z3)b- are, each independently, denoting a group with one or two six-membered rings.

The groups -A'-(f-A2),- and -(A 3_Z3)b- may be identical or different. Particularly preferred are compounds wherein -A'-(Z2-A 2)a- and -(A 3_ Z3)b- are different.

Preferred subformulae for the groups -A' _(Z2 -A 2),- and -(A 3_Z3)b- are listed below. For reasons of simplicity, Phe in these groups is 1, 4phenylene, Phe L is a 1,4-phenylene group which is substituted by 1 - f to 4 groups L, with L being F, Cl, CN or an optionally fluorinated alkyl, alkoxy or alkanoyl group with 1 to 4 C atoms, and Cyc is 1,4 cyclohexylene. The following list of preferred groups -A' _(Z2 -A 2)a- and -(A 3_Z3)b- is comprising the subformulae 11-1 to 11-9 as well as their mirror images -Phe -Cyc -PheL -Phe-Z-Phe -Phe-Z-Cyc -Cyc-Z-Cyc -Phel--Z-Phe -Phel--Z-Cyc -PheL-Z-PheL- Particularly preferred are the subformulae 11-1, 11-2, 11-3 and 11-5.

In these preferred groups Z has the meaning given in formula 1 described above. Preferably Z is -COO-, -OCO-, -CH2CH2 -CH=CH-COO- or a single bond.

11-1 11-2 11-3 11-4 11-5 11-6 11-7 11-8 11-9 L is preferably F, Cl, CN, N02, CH3, C21-15, OCH3, 0C21-15, COCH3, COC21- 15, CF3, OCF3, OCHF2, OC2175, in particular F, Cl, CN, CH3, C21-15, OCH3, COCH3 and OCF3, most preferably F, CH3, OCH3and COCH3.

Very preferably -A' _(Z2 -A 2)a- and -(A 3_Z3)b- are, independently of each other, selected from the following formulae and their mirror images (L)r lla -C)- (L)r (L)r - - (L)r (L)r (L)r --t-coo-- (L)r (L)r CH2CH2 wherein L has the meaning given above and r is 0, 1 or 2.

lic lid lie lif llg (L)r The group -(- in these preferred formulae is very preferably L L L L denoting -5- 1 1 or -g- L furthermore -( 0 - 1 L with L having each independently one of the meanings given above.

Particularly preferred are the subformulae lia to lie, in particular the subformulae lia and lib.

If R is an alkyl or alkoxy radical, i.e. where the terminal CH2group is replaced by -0-, 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, propyi, butyl, pentyl, hexy], heptyf, octyi, ethoxy, propoxy, butoxy, pentoxy, hexoxy, heptoxy, or octoxy, furthermore methyl, nonyi, decyi, undecyl, dodecyl, tridecyl, tetradecyl, pentadecy], methoxy, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy or tetradecoxy, for example.

Oxaalkyl, i.e. where one CH2 group is replaced by -0-, is preferably straight-chain 2-oxapropyl (=methoxymethyi), 2- (=ethoxymethyl) or 3-oxabutyi (=2-methoxyethyi), 2-, 3-, or 4-oxapenty], 2-, 3-, 4-, or 5 oxahexyi, 2-, 3-, 4-, 5-, or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7oxaoctyi, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl or 2-, 3-, 4-, 5-, 6-,7-, 8- or 9 oxadecyi, for example.

In the compounds of formula 1 R may be an achiral or a chiral group. In case of a chiral group they are preferably selected according to the following formula Ill:

-X 1 -Q 1 - H- 2 1 Q 3 Ill wherein X' is -0-, -S-, -CO-, -COO-, -OCO-, -OCOO- or a single bond, Q' is an alkylene or alkylene-oxy group with 1 to 10 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 halogen 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-O-, -S-CO- or -CO-S- in such a manner that oxygen atoms are not linked directly to one another, 03 is halogen, a cyano group or an alkyl or alkoxy group with 1 to 4 C atoms different from Q2.

Preferred chiral groups R are 2-butyl (=1-methylpropyl), 2 methylbutyl, 2-methylpentyl, 3-methylpenty], 2-ethylhexyl, 2 propylpenty], 2-octyl, in particular 2-methylbutyl, 2-methylbutoxy, 2 methylpentoxy, 3-methylpentoxy, 2-ethylhexoxy, 1-methylhexoxy, 2 octyloxy, 2-oxaT3-methyibuty], 3-oxa-4-methylpentyi, 4-methylhexyl, 2-nonyi, 2-decyl, 2-dodecyl, 6-methoxyoctoxy, 6-methyloctoxy, 6 methyloctanoyloxy, 5-methyiheptyloxycarbonyi, 2-methyibutyryioxy, 3-methylvaleroyloxy, 4-methyihexanoyloxy, 2-chlorpropionyloxy, 2 chloro-3-methylbutyryloxy, 2-chloro-4-methylvaleryloxy, 2-chloro-3 methylvaieryloxy, 2-methyl-3-oxapentyi, 2-methyi-3-oxahexyi, 1 methoxypropyi-2-oxy, 1-ethoxypropyi-2-oxy, 1-propoxypropyi-2-oxy, 1-butoxypropyl-2-oxy, 2-fluorooctyloxy, 2-fluorodecyloxy for example.

In addition, compounds of formula 1 containing an achiral branched 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 (=methyl pro pyi), isopentyl (= 3- methyl butyl), isopropoxy, 2-methyl propoxy and 3-methylbutoxy.

Very preferably R in formula 1 is halogen, cyano or an optionally fluorinated achiral or chiral alkyl or alkoxy group with 1 to 15 C atoms.

Another preferred embodiment of the present invention relates to compounds of formula 1 wherein R is denoting P-(SP-X)n- P in formula 1 is preferably 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.

As for the spacer group Sp in formula 1 all groups can be used that are known for this purpose to the 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 -0-, -S-, -NH-, 10 -N(CH3)-, -CO-, -0-CO-, -S-CO-, -0-COO-, -CO-S-, -CO-0-, -CH(halogen)-, -CH(CN)-, -CH=CHor -C=-C-.

Typical spacer groups are for example -(CHA,-, -(CH2CH20)p -CH2CH2 -CH2CH2-S-CH2CH2- or -CH2CHAH-CH2CH2-,with o being an integer from 2 to 12 and p being an integer from 1 to 3.

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

Especially preferred are inventive compounds of formula 1 wherein Sp is denoting an alkyl or alkoxy group with 2 to 6 C atoms. Straight chain alkyl or alkoxy groups are especially preferred.

In another preferred embodiment of the invention the chiral compounds of formula 1 comprise at least one spacer group Sp that is a chiral group of the formula IV:

1 4 -Q -CH-Q _ 1 a 3 wherein IV Q' and 03 have the meanings given in formula Ill, and Q4 is an aikylene or alkylene-oxy group with 1 to 10 C atoms or a single bond, being different from d.

In the event that R is denoting P-Sp-X-, the two spacer groups Sp in the compounds of formula 1 may be identical or different.

Of the preferred compounds described above particularly preferred are those wherein n is 1.

Further preferred are compounds comprising both a group P-(SP-X)nwherein n is 0 and a group P-(Sp-X),- wherein n is 1.

Another object of the present invention is a polymerizable liquid crystalline composition comprising at least two polymerizable compounds, at least one of which is a compound of formula 1.

Another object of the present invention is the use of the inventive mesogenic compounds and compositions for the preparation of linear or crosslinked liquid crystalline polymers, in particular for the preparation of oriented films of linear or crosslinked liquid crystalline polymers.

A further object of the invention is a linear or crosslinked polymer that is obtainable by polymerization of one or more polymerizable mesogenic compounds of formula 1 or by polymerization of a composition comprising at least one polymerizable mesogenic compound of formula 1 and optionally further comprising one or more other polymerizable or non-polymerizable mesogenic or non mesogenic compounds.

Other polymerizable mesogenic compounds that can be used as comonomers together with the inventive compounds for the preparation of polymers or polymer films are disclosed for example in WO 93122397; EP 0,261,712; DE 195,04,224; WO 95122586 or WO 97100600. The compounds disclosed in these documents, however, are to be regarded merely as examples that shall not limit the scope of this invention.

The polymerizable mesogenic compounds used as comonomers together with the inventive compounds are preferably selected of formula V P-(SP-X)AA'-Z)m-A 2 -R' wherein P, Sp, X, n, A' and A2 have the meaning of formula 1, m is 0, 1 or 2, Z has one of the meanings of Z2 in formula 1, and R' has one of the meanings of R in formula 1.

Typical examples representing such polymedzable mesogenic compounds are shown in the following list of compounds, which should, however, be taken only as illustrative and is in no way intended to restrict, but instead to explain the present invention:

L 1 L 2 CH 2=CHCOO(CH coo OCO-F \\-O(CH 2)y OOCCH=CH2 2).0 -0CH2=CHCOO(CH2)X0 -0- coo -& R 0 CH2=CHCOO(CHA0 -C-coo R 0 CH2=CHCOO(CH2)10-0 R 0 (V1) (V2) (V3) (V4) 1 L 1 CH2=CHCOO(CHAO -C- coo -c oco-c- R 0 CH2=CHCOO(CHAO-O-CH=CH -COO -C- R 0 0 / \ (CH2).0 -0- coo --& R 0 CH2=CHCOO(CHA0 -0- coo -& (COO) v CH(CH3)C,H13 CH 2 =CHCOO(CH AO -0-COO CH 2 CH(CH 3)C2 H 5 L CH CH(CH H 2=CHCOO- COO -0-CH2 3)C2 5 CH2=CHCOO(CH2).0-CY-O-COOCH(CH3)C6H,3 (V5) (V6) (V7) (V8) (V9) (V1 0) (V1 1) L 1 CCHCOO(CH COO COO--CH CH(CH H H2= AO -0- 2 3)C2 5 CH2=CHCOO(CH AO -0-COO (V1 2) (V1 3) CH 2=CHCOO(CH2).0-0-COO"""1 CH2=CHCOO(CH2).0-C-COOCH(CH3)CH2OR 0 CH 2=CHCOO(CH 2).0 -3- coo CH 2=CHCOO(CH2).0-0-0-CO,,ay R 0 (V14) (V1 5) (V1 6) (V1 7) In these compounds x and y are each independently 1 to 12, F is a 1,4-phenylene or 1,4-cyclohexylene group, RO is halogen, cyano or an optionally halogenated alkyl or alkoxy group with 1 to 12 C atoms and L' and L 2 are each independently H, F, Cl, CN, or an optionally halogenated alkyl, alkoxy or alkanoyl group with 1 to 7 C atoms.

The polymerizable mesogenic compounds of formula V can be prepared by 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-Veriag, Stuttgart. Further methods of their preparation can be taken for example from the above cited WO 93/22397; EP 0 261 712; DE 195,04,224; WO 95122586 and WO 97/00600.

The poiymerizable mesogenic compounds of formula 1 and formula V can be mono- or bifunctional, i.e. they can comprise one or two polymerizable functional groups.

In a preferred embodiment of the invention the polymerizable liquid crystalline composition comprises at least one bifunctional compound of formula 1 together with one or more monofunctional compounds of formula V.

In another preferred embodiment of the present invention the polymerizable liquid crystalline composition comprises at least one monofunctional compound of formula 1 and at least one bifunctional compound of formula V.

The polymerizable mesogenic compounds of formula 1 may also further comprise one or more chiral groups. Inventive compounds of formula 1 with a chirai group can be used e.g. for the prepration of thermochromic liquid crystalline mixtures or as chiral dopants.

In a preferred embodiment of the present invention the poiymerizable liquid crystalline composition comprises at least one chiral polymerizable compound.

In another preferred embodiment the polymerizable liquid crystalline composition comprises at least one polymerizable chiral compound of formula 1 with one polymerizable group.

In another preferred embodiment the polymerizable liquid crystalline composition comprises at least one polymerizable chiral compound of formula 1 with two polymerizable groups.

It is also possible for the inventive composition to comprise one or more non-polymerizable chiral compounds, which may be mesogenic or non-mesogenic, in addition or alternatively to the chiral poiymerizable compounds. For example, commercially available dopants, like e.g. R 811 or R 1011 (from Merck KGaA, Germany) can be used for this purpose.

Polymerizable mesogenic compositions are preferred that comprise 1 to 6, preferably 1 to 3 compounds of formula 1.

- 1 7- In a preferred embodiment of the present invention the polymerizable liquid crystalline composition comprises 1 to 80 % by weight, preferably 2 to 60 %, in particular 5 to 40 % by weight of one or more compounds of formula 1.

In the polymerizable compositions comprising monofunctional compounds of formula 1, the concentration of each of these compounds is preferably 1 to 60 %, in particular 2 to 45 %, very preferably 3 to 35 % by weight of the total mixture.

In the polymerizable compositions comprising bifunctionai compounds of formula 1, the concentration of each of these compounds is preferably 1 to 50 %, in particular 2 to 35 %, very preferably 3 to 25 % by weight of the total mixture.

The inventive polymerizable liquid crystalline compositions can additionally comprise one or more other suitable components, such as, for example, catalysts, sensitizers, stabilizers, co-reacting monomers or surface-active compounds.

It is also possible, in order to increase crosslinking of the polymers, to add up to 20% of a non mesogenic compound with two or more polymerizable functional groups to the poiymerizable composition alternatively or additionally to the multifunctional polymerizable mesogenic compounds.

Typical examples for difunctional non mesogenic monomers are alkyldiacrylates or alkyldimethacrylates with alkyl groups of 1 to 20 C atoms. Typical examples for non mesogenic monomers with more than two polymerizable groups are thmethylpropanetrimethacrylate or pentaerythritoltetraacrylate.

Liquid crystalline polymers can be obtained from the inventive polymerizable compounds and compositions e.g. by solution polymerization or by in-situ polymerization.

For example, solution polymerization can be carried out in a solvent like dichloromethane, tetrahydrofuran or toluene using A1BN as an initiator and heating for 24 hours at 30 to 60 C.

The in-situ polymerization of polymerizable liquid crystalline compounds is described in detail by D.J.Broer et al., Makromol.Chem. 190, 2255ff. and 3202ff. (1989).

The reactive liquid crystal compounds and compositions according to this invention are preferably polymerized in situ as described in the foregoing and the following.

The inventive compounds and polymerizable liquid crystalline compositions are particularly useful for the preparation of anisotropic polymer films, such as nematic or cholesteric polymer films, with uniform molecular orientation.

Thus, another object of the invention is an anisotropic polymer film with an oriented liquid crystalline phase that is obtainable by polymerizing a polymerizable liquid crystalline composition comprising at least one polymerizable mesogenic compound of formula 1.

To prepare an anisotropic polymer film with uniform orientation, an inventive polymerizable mesogenic composition is preferably coated onto a substrate, aligned and polymerized in situ by exposing them to heat or actinic radiation. Alignment and curing are preferably carried out in the liquid crystalline phase of the composition.

Actinic radiation means irradiation with light, like LIV light, IR light or visible light, irradiation with X-rays or gamma rays or irradiation with high energy particles, such as ions or electrons. As a source for actinic radiation for example a single UV lamp or a set of UV lamps can be used. Another possible source for actinic radiation is a laser, 35 like e.g. a UV laser, an IR laser or a visible laser.

When polymerizing by means of UV light, for example a photoinitiator can be used that decomposes under UV irradiation to produce free radicals or ions that start the polymerization reaction.

It is also possible to use a cationic photoinitiator, when curing reactive mesogens with for example vinyl and epoxide reactive groups, that photocures with cations instead of free radicals.

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

Preferably the polymerizable liquid crystalline composition comprises 0. 01 to 10 %, in particular 0.05 to 8 %, very preferably 0. 1 to 5 % by weight of a photoinitiator, especially preferably a UVphotoinitiator.

In a preferred embodiment of the invention the polymerization of the polymerizable mesogenic composition is carried out under an atmosphere of inert gas, preferably under a nitrogen atmosphere.

As a substrate for example a glass or quarz sheet as well as a plastic film or sheet can be used. It is also possible to put a second substrate on top of the coated mixture prior to, during andfor after polymerization. The substrates can be removed after polymerization or not. When using two substrates in case of curing by actinic radiation, at least one substrate has to be transmissive for the actinic radiation used for the polymerization.

Isotropic or birefringent substrates can be used. In case the substrate is not removed from-the polymerized film after polymerization, preferably isotropic substrates are used.

Preferably at least one substrate is a plastic substrate such as for example a film of polyester such as polyethyleneterephthalate (PET), of polyvinylalcohol (PVA), polycarbonate (PC) or triacetylcel 1 u lose (TAC), especially preferably a PET film or a TAC film. As a birefringent substrate for example an uniaxially stretched plastic film can be used. For example PET films are commercially available from ICI Corp. under the trade name Melinex.

In a preferred embodiment of the present invention, the inventive polymerizable mesogenic composition is coated as a thin layer on a substrate or between substrates and is aligned in its liquid crystal phase to give a uniform orientation.

A uniform orientation can be achieved for example by shearing the mixture, e.g. by means of a doctor blade. It is also possible to apply an alignment layer, for example a layer of rubbed polyimide or sputtered SiOx, on top of at least one of the substrates. In some cases, the mixtures orient themselves spontaneously on the substrate, or good alignment is achieved already by the act of coating the mixture.

In another preferred embodiment, a second substrate is put on top of the coated material. In this case, the shearing caused by putting together the two substrates is sufficient to give good alignment.

It is also possible to apply an electric or magnetic field to align the coated mixture.

In some cases it is of advantage to apply a second substrate not only to aid alignment of the poiymerizable mixture but also to exclude oxygen that may inhibit the polymerization. Alternatively the curing can be carried out under an atmosphere of inert gas. However, curing in air is also possible using suitable photoinitiators and high lamp power. When using a cationic photoinitiator oxygen exclusion most often is not needed, but water should be excluded.

For the preparation of anisotropic polymer gels, the polymerizable mesogenic compound can be polymerized in situ as described above, however, in this case alignment of the polymerizable mixture is not necessarily required, although it may be desired for specific applications.

The invention also relates to the use of inventive compounds, compositions and polymers in liquid crystal displays, such as STN, TN, AMID-TN,temperature compensation, guest-host, phase change or surface stabilized or polymer stabilized cholesteric texture (SSCT, PSCT) displays, in active and passive optical elements like polarizers, compensators, alignment layers, colour filters or holographic elements, in adhesives, synthetic resins with anisotropic mechanical properties, cosmetics, diagnostics, liquid crystal pigments, for decorative and security applications, in nonlinear optics, optical information storage or as chiral dopants.

The inventive compounds of formula 1 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-Veriag, Stuttgart. Some specific methods of preparation can be taken from the examples.

Furthermore, inventive compounds of formula 1 can be prepared according to the following reaction scheme or in analogy thereto:

Scheme 1 HO-()-OCH 2 HO(C1-12),Cl Nal, NaOH, IMS HO(CH2)50 -c)_ OCH 2-(:) Pd/C THF HO(CH2)so- OH CICH2CH2CO2H pTSA, DCM CICH2 CH 2COO-(CH 2)sO -&OH 0:Y-CtH 2t+l + HOOC-1\/ 0 DCC, DMAP, Toluene (1.1) 0 CICH 2 CH2COO-(CH 10 -&ooc-- CtH2t+l 0 (1.2) NEt 31 DCM 0 H C=CHCOO-(CH) 0 ooc-:: -CtH2t+1 0 2 s (1.3) wherein s and t are each independently an integer from 1 to 15.

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

In the foregoing and in the follovAng 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 phase behaviour of the compounds: K = crystalline; N = nernatic; S = smectic; Ch = cholesteric; 1 = isotropic. The numbers between these symbols indicate the phase transition temperatures in degree Celsius.

Furthermore. the following abbreviations are used:

IMS = industrial methylated spirits DCM = dichloromethane is DCC = dicyclohexylcarbodiimide DMAP = dimethylamino pyridine pTSA = para-toluenesuifonic acid mple 1 Compound (1) has been prepared according to reaction scheme 1 (with s =4andt= 7) 0- CH2=CH-COO-(CH2)4-0 -( 00C C.7HIS (1) 4-F4-(2-ch)oroethylcarbonyloxv)butoxylphenvi-5-hepty]-1,3-dioxane2carboxylate (1.2) Phenol (1.1) (s = 4) from scheme 1 (3.0 9, 0.11 M), trans2n-heptyl 1.3-dioxane-5-carboxylic acid (2.5 g, 0.011 M), dicyclohexylcarbo diimide (2.49 g. 0.012 M) and a catalytic amount of dimethylamino pyridine were stirred in dichloromethane (50 m]) overnight. The side product dicyclohexyl urea was removed by filtration. The filtrate was washed with aqueous NaHCO3, water and then dried over Na2S04. The product was used without further purification in the next stage.

4:L4-(5-heptti-1,3-dioxan-2-v)carbonvioxv)phenoxvlbulyJ aelylate (1.3) 4-[4-(2-chloroethylcarbonyloxy)butoxy]pheny]-5-hepty]-1,3-dioxane2carboxylate (4.8 g, 0.01 M) and triethylamine (2.1 MI, 0.015 M) were stirred in dich loromethane (100 rnl) at 35 C for 24 hours. The mixture was allowed to cool to room temperature, washed with water (2 x 100 mi), the chlorinated phase was removed, dried over Na2SO4and evaporated to leave a pale yellow solid. Purification was achieved by flash column chromatography using dichloromethane as eluant. Evaporation of the appropriate fractions left a white solid residue.

Compound (1) has a melting point of 62 Q a birefringence An = 0.07, and an extrapolated clearing temperature TN4 = 280C.

&n and TN4 of compound (1) were determined in the nematic host mixture ZLI-3086 (commercially available from Merck KGaA, Darmstadt, Germany) at a concentration of 8.4 % by weight.

The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants andfor operating conditions of this invention for those used in the preceding examples.

From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various conditions and usages.

Claims (12)

1. Claims

   Polymerizable mesogenic compound of formula 1 P-(SP-X)n-A 1 -(Z 2 -A 2),,-Z 1 ()- (Z-A 3)b -R wherein 1 0 P is CH2=CW-COO-,WCH=CH-0-, W1-IC-CHor CH2=CH-Phenyi-(0)k- with W being H, CH3 or Cl and k being 0 or 1, Sp is a spacer group having 1 to 20 C atoms, X is -0-, -S-, -CO-, -COO-, -OCO-, -CO-NH-, -NH-CO-, CH2CH2-, -OCH2-, - CH20-, -SCH2-, -CH2S-, -CH=CH-, CH=CH-COO-, -OCO-CH=CH-, -C-=C- or a single bond, n is 0 or 1, Z1 is -COO-, -OCO-, -CH2CH2-, -OCH2-, -CH20-, -OCH2-0-, -CH=CH-, -CH=CH-COO-, -OCO-CH=CH- or -C=-C-, Z2 and Z3 are each independently -COO-, -OCO-, -CH2CH2-, -OCH2-, -CH20-, - CH=CH-, -CH=CH-COO-, -OCO-CH=CH-, -C=-C-, or a single bond, A', A 2 and A 3 are each independently 1,4-phenylene in which, in addition, one or more CH groups may be replaced by N, 1,4-cyclohexylene in which, in addition, one or two nonadjacent CH2 groups may be replaced by 0 andlor S, 1,4cyclohexenylene, 1,4-bicyclo(2,2,2)octylene, piperidine1,4-diyl, naphthalene-2,6-diyi, decahydronaphthalene-2,6diyi, or 1,2,3,4-tetrahydro-naphthalene-2,6-diyl, it being possible for all these groups to be unsubstituted, mono- or polysubstituted with halogen, cyano or nitro groups or alkyl, alkoxy or alkanoyl groups having 1 to 7 C atoms wherein one or more H atoms may be substituted by F or Cl, a and b are each independently 0, 1 or 2, xt X9 is - or X _CX19 X' and X" are independently of each other -0- or -S-, and R is H, CN, halogen or a straight-chain or branched alkyl radical with up to 25 C atoms which may be unsubstituted, mono- or polysubstituted by halogen 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 0-, -S-, -NH-, -N(CH3)-, -CO-, -COO-, -OCO-, -OCO-O-, -SCO-, -CO-S- or -C=-C- in such a manner that oxygen atoms are not linked directly to one another, or alternatively R is denoting P-(SP-X)n-.
2. 2. Polymerizable mesogenic compound according to claim 1, characterized in that it is selected of the following formulae 0 P-(Sp-X),-A 1 - (Z 2 -A2).-Zi-( (Z-A')b-R 0 la 0 P-(SP-X),-A 1 - (Z 2 -A2)a-Z 1: (Z'_A')b-R 0 lb wherein P, Sp, X, n, A', A2, A', Z1, Z2, Z3, a, b and R have the meanings given in formula 1.
3. Polymerizabie mesogenic compound according to claim 1 or 2, characterized in that Z1 is -COO- or -OCO-.
4. 4. Polymerizable mesogenic compound according to at least one of claims 1 to 3, characterized in that R is P-(Sp-X),-, with P, Sp, X and n having the meanings of formula 1.
5. 5. Polymerizable mesogenic compound according to at least one of claims 1 to 4, characterized in that R is halogen, CN or optionally fluorinated achiral or chiral alkyl or alkoxy with 1-15 C atoms.
6. 6. Polymerizabie mesogenic compound according to at least one of claims 1 to 5, characterized in that one or both of -A' _(Z2_A 2)a- and -(A 3_Z3)bare independently of each other selected from the following formulae and their mirror images (L)r lla lib (L)r (L)r lic (L)r lid lie (L)r (L)r -5 coo- - llf (QT)r wherein L in each case independently denotes halogen, a cyano or nitro group or an alkyl, alkoxy or alkanoyl group having 1 to 7 C atoms, wherein one or more H atoms may be substituted by F or C], and r is 0, 1 or 2.
7. 7. Composition comprising at least two poiyrnerizable mesogenic compounds, characterized in that at least one compound is a compound according to at least one of claims 1 to 6.
8. 8. Composition according to claim 7, characterized in that it comprises at least one reactive mesogenic compound having two polymerizable terminal groups.
9. 9. A polymerizable mesogenic compound substantially as described in Example 1.
10. 10. Linear or crosslinked (co)po"er obtained or obtainable by (co)polyrnerization of polymerizable mesogenic compound(s) or composition(s) according to at least one of claims 1 to 9.
11. 11.

    Use of a polymerizable mesogenic compound or composition according to at least one of claims 1 to 10 in a liquid crystal display, such as an TIN, TN, AMD-7N, temperature compensation, guest-host, phase change or surface stabilized or polymer stabilized cholestric texture (SSCT, PSCI) display, in an active and passive optical element like a polarizer, compensator, alignment layer, colour filter or holographic element, in an adhesive, synthetic resin with anisotropic mechanical properties, cosmetic, diagnostic, liquid crystal pigment for decorative and security applications, in a nonlinear optic, optical information storage or as a chiral dopant.
12. 12. A liquid crystal display, preferably an STN, TN, AMD-7IN, temperature compensation, guest-host, phase change or surface stabilized or polymer stabilized cholestric: texture (SSCT, PSCI) display, an active and passive optical element preferably a polarizer, compensator, alignment layer, colour filter or holographic element, an adhesive, synthetic resin with anisotropic mechanical properties, cosmetic, diagnostic or liquid crystal pigment for decorative and security applications, a nonlinear optic, optical information storage or chiral dopant comprising a polymerizable mesogenic compound or composition according to at least one of claims 1 to 10.

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