DE19941567A1 - New liquid crystal compounds containing 3-hydroxyacrylic acid ester units, having high clear point, dielectric anisotropy and double refraction, useful e.g. in displays or (electro)optical components - Google Patents

Abstract

New liquid crystal compounds (I) contain mono- or di- or trimeric ester structural elements derived from 3-hydroxyacrylic acid. New liquid crystal compounds (I) (including oligomeric or polymeric compounds) contain at least one unsaturated (poly)ester structural element of formula (M') or its mirror image of formula (M''). m = 1, 2 or 3. Independent claims are included for: (i) the preparation of preferred compounds (I); and (ii) liquid crystal media comprising at least two liquid crystalline compounds, which include at least one compound (I).

Description

The invention relates to new liquid-crystalline compounds containing at least one structural element of the formula M 'or their mirror image M "

where m is 1, 2 or 3.

The compounds according to the invention comprise low molecular weight in particular monomeric, as well as oligomeric or polymeric Links. The invention further relates to a method for Production of new liquid crystalline compounds containing a structural element of the form M 'or M ", and, in the case of oligomeric and polymeric compounds according to the invention, their Raw materials. The invention further relates to the use of Liquid-crystalline compounds according to the invention containing a Structural element M 'or M "for the production of liquid crystalline Oligomers, polymers and polymer networks or as components liquid crystalline media, liquid crystalline media, oligomers, Polymers and polymer generators containing these compounds, as well as their use in optical elements or for Decorative purposes.

It is known that the intermediate links Z ', which are in liquid crystals of the general structure R'-Z'-A'-Z'-A'-Z'-A'-Z'-R 'or comparable Structures the ring elements A 'with each other or with the Connect end groups R ', the properties of the liquid crystal each different according to the chemical nature of this pontic can influence.

Intermediate links known to date are, for example, ester, Ethylene, ethenylene, ethynylene, azo, azoxy, methyleneoxy, Difluoroethenylene, n-butylene or Schiff base groups; the the simplest link is the single bond.  

The invention was based on the object, new stable to provide liquid crystalline or mesogenic compounds which especially for use as components of liquid crystalline Media and for the production of liquid crystalline polymers are suitable.

The compounds of the invention should in particular advantageous properties, such as a high clearing point, a broad one liquid crystalline phase range and advantageous values for the dielectric anisotropy and birefringence, or in induce the media and polymers of the invention.

It has now been found that the structural element M

as well as its mirror image as an intermediate link in liquid crystals shows mesogenic or mesogenicity-promoting effect.

The structural element M thus acts as an intermediate element in liquid crystals compared to corresponding derivatives with known ones Pontics, especially with a single bond as Intermediate link, generally to a comparative increase in Clearing point, the dielectric anisotropy Δε and the Birefringence Δn.

The structural element M can be used one or more times in succession Mesogenic link in known and unknown Liquid crystal structures are installed. It can be ring groups connect with each other and / or with end groups. One or A plurality of structural elements M can also be created using known ones Intermediate links must be connected as listed above.

Liquid crystals according to the invention containing one or more Structural elements M can be liquid-crystalline as components Media are used, especially for liquid crystal displays,  based on the principle of the twisted cell, the guest-host effect, the Effect of deformed phases or static or dynamic scatter, continue to be in cholesteric or ferroelectric liquid crystal displays or IPS (in plane switching), polymer gel or PDLC displays (polymer dispersed liquid crystal displays).

Compounds according to the invention which are reactive or contain polymerizable group can also for Production of liquid crystalline oligomers and polymers, Polymer networks or polymer films can be used. Further can oligomeric and polymeric compounds according to the invention containing a structural element M 'or M "directly in the form of Networks or films.

The above-mentioned polymers or polymer films are suitable for. B. for use in electro-optical displays, optical Polarization or compensation films, orientation layers, Color filters or holographic elements, in photocrosslinkable Adhesives, tensile fibers, liquid crystalline pigments, colorants or cosmetics, diagnostic applications, as Security markings, as well as in the non-linear optics and optical data storage.

Compounds according to the invention with one or more chiral Structural elements are suitable for use as dopants.

Acryloxyacrylates with the structural element -COO-CH = CH-COO- are described in T. Wakabayashi et al., Tetrahedron Lett. 36, 5585 (1995) and L.A. Miller, C.A. 61, 9405 h, 1964, it is found there however, no indication of liquid crystalline compounds.

The invention thus relates to liquid-crystalline compounds containing at least one structural element of the formula M 'or its mirror image M "

where m is 1, 2 or 3.

Compounds according to the invention are particularly preferred containing at least one structural element of the formula M 'or M ", which have at least one polymerizable group.

Further preferred are oligomeric and polymeric according to the invention Compounds containing at least one structural element of the formula M 'or M ".

Compounds according to the invention are further preferred containing at least one structural element of the formula M 'or M ", which have at least one chiral group.

Compounds according to the invention are further preferred containing at least one structural element of the formula M 'or M ", which have at least one chromophoric group.

The liquid-crystalline compounds according to the invention are preferably selected from formula I.

R ¹ -Z ¹ - (A ¹ ) _a -Z ² - (A ² ) _b -Z ³ - (A ³ ) _c -Z ⁴ - (A ⁴ ) _d -Z ⁵ -R ² I

where the individual radicals have the following meaning
A ¹ to A ⁴ each independently of one another -A- (ZB) _e -, a double-bonded chiral structural element G ² or a double-bonded chromophoric group T ² ,
A and B are each independently 1,4-phenylene, in which one or two CH groups can also be replaced by N, trans-1,4-cyclohexylene, in which one or two CH ₂ groups can also be replaced by O and / or S. may be trans-1,4-cyclohexenylene, 1,4-bicyclo (2,2,2) octylene, naphthalene-2,6-diyl, piperidine-1,4-diyl, decahydronaphthalene-2,6-diyl, 1 , 2,3,4-tetrahydronaphthalene-2,6-diyl, cyclobutane-1,3-diyl, or wherein in these groups also 1 to 4 H atoms by F, Cl, CN, NO ₂ or unsubstituted or mono- or alkyl, alkoxy or alkanoyl with 1 to 7 carbon atoms substituted by F or Cl can be substituted several times,
Z each independently of one another -N = N-, -N = N (O) -, -CH = N-, -COO-, -OCO-, -CH ₂ CH ₂ -, - (CH ₂ ) ₄ -, -OCH ₂ -, -CH ₂ O-, -CX ¹ = CX ² -, -CH ₂ -CH = CH-CH ₂ -, -CH = CH-COO-, -OOC-CH = CH-, -C∼C- , -C∼C-COO-, -OOC-C∼C-COO- or a single bond,
e 0, 1 or 2,
Z ¹ to Z ⁵ each independently of one another have one of the meanings given for Z, M 'or M ",
a, b, c and d are each independently 0, 1 or 2, the sum a + b + c + d having to be different from 0,
R ¹ H, F, Cl, CN, NO ₂ , NCS, straight-chain or branched alkyl having 1 to 25 C atoms, in which one or more CH ₂ groups are also represented by -O-, -S-, -NH-, -N (CH ₃ ) -, -CO-, -COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, -CH = CH- or -C∼C- so can be replaced that O and / or S atoms are not directly linked, and in which one or more H atoms by OH, NH, COOH, F, Cl, CH ₃ , OCH ₃ , CN, CF ₃ or -C~C- may be replaced, a monovalent chiral structure element G ¹ is a monovalent chromophore group T ¹ or P- (Sp-X) n-,
R ² each independently one of the meanings mentioned for R ¹ , - (O) _q -CX ¹ = CX ² X ³ or, in the case of a linkage with a non-aromatic ring, also = CX ¹ X ² or

where q is 0 or 1 and X ¹ , X ² and X ³ each independently represent H or F,
P CH∼C-COO-, CH ₂ = CW-COO-, WCH = CH-O-,

CH ₂ = CH-phenyl- (O) _k -, N = C = O-, H ₂ N-, HO-, HOOC- or HS-, where WH, CH ₃ or Cl and k is 0 or 1,
Sp is a spacer group with up to 20 C atoms,
X -O-, -S-, -CO-, -COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S- or a single bond, and
n 0 or 1,
with the proviso that at least one of the groups Z ¹ to Z ⁵ denotes M 'or M ".

Another object of the invention is a process for the preparation of liquid-crystalline compounds containing at least one structural element of the formula M 'or M ", characterized in that

• a) a compound containing a propinoyl group of the formula Ia1
  R ¹ -Z ¹ - (A ¹ ) _a -Z ² - (A ² ) _b -OOC-C∼CH Ia1
  optionally reacted one or more times with propiolic acid HC∼C-COOH, the carboxyl group of propiolic acid being added to the C∼C triple bond of Ia1, and then the product of the formula Ia
  R ¹ -Z ¹ - (A ¹ ) _a -Z ² - (A ² ) _b -OOC-CH = CH) _m-1 -OOC-C∼CH Ia
  with a carboxylic acid of formula Ib
  HOOC- (A ³ ) _c -Z ⁴ - (A ⁴ ) _d -Z ⁵ -R ² Ib
  by an addition reaction as described above to a compound of the formula I, or
• b) a carboxylic acid of the formula Ic1
  R ¹ -Z ¹ - (A ¹ ) _a -Z ² - (A ² ) _b -COOH Ic1
  optionally reacted one or more times with propiolic acid, the carboxyl group of Ic1 being added to the C∼C triple bond of propiolic acid, and then the product of the formula Ic
  R ¹ -Z ¹ - (A ¹ ) _a -Z ² - (A ² ) _b - (COO-CH = CH) _m-1 -COOH Ic
  with a propinoyl derivative of the formula Id
  HC∼C-COO- (A ³ ) _c -Z ⁴ - (A ⁴ ) _d -Z ⁵ -R ² Id
  by an addition reaction as described above to a compound of the formula I, or
• c) a hydroxycarboxylic acid of the formula Ie
  HO- (A ² ) _b -COOH Ie
  optionally reacted one or more times with propiolic acid, the product of the formula Ie1 being formed by adding the carboxyl group of 1e to the C∼C triple bond of propiolic acid, or by esterifying the hydroxyl group of Ie with the -COOH group of propiolic acid of the formula Ie2 is formed, or the product of the formula Ie3 is formed by both of the reactions mentioned above,
  HO- (A ² ) _b -COO- (CH = CH-COO) _m-1 -H Ie1
  H- (C∼C-COO) _m-1 -O- (A ² ) _b -COOH Ie2
  H- (C∼C-COO) _m-1 -O- (A ² ) _b -COO- (CH = CH-COO) _m-1 -H Ie3
  and
  • 1. in the product of the formula Ie1, the terminal acid group with a propinoyl derivative of the formula Id or Iaa
    R ¹ -Z ¹ - (A ¹ ) _a -OOC-C∼CH Iaa
    reacted as described under a) and b), and the terminal hydroxyl group with a carboxylic acid of the formula Id or Icc
    R ¹ -Z ¹ - (A ¹ ) _a - (COO-CH = CH) _b-1 -COOH Icc
    esterified, or
  • 2. in the product of the formula Ie2, the terminal acid group is reacted with a propinoyl derivative of the formula laa or Id as described under a) and b), and if appropriate the terminal propinoyl group is reacted with a carboxylic acid of the formula Ib or Icc as described under a) and b) , or optionally the terminal hydroxyl group is esterified with a carboxylic acid of the formula Icc or Id, or
  • 3. with the product of the formula Ie3, carries out the reactions described under c1) and c2), the sequence of the reaction steps described in c1) to c3) being arbitrary,
  or
• d) a dihydroxy compound of the formula If
  HO- (A ² ) _b -OH If
  or a dicarboxylic acid of the formula Ig
  HOOC- (A ² ) _b -COOH Ig
  can react one or more times with propiolic acid in the manner described under a) to c) and then reacted with a propinoyl derivative of the formula Iaa or Id and / or with a carboxylic acid of the formula 1b or Icc,

where R ¹

, R ²

, A ¹

to A ⁴

, Z ¹

to Z ⁵

and a, b, c, d and m have the meaning given in formula I, and
in the compounds of the formula Ia1, Ia, Ic1 and Ic a + b ≠ 0,
in the compounds of the formula Ib and Id c + d ≠ 0,
in the compounds of the formula Ie, Ie1, Ie2, Ie3, If and Ig b ≠ 0, and
in the compounds of formula laa and Icc a + 0 applies.

Another object of the invention is the use of Compounds according to the invention as components liquid-crystalline media and for the production of liquid-crystalline Polymers, polymer networks and polymer films.

Another object of the invention is a liquid crystalline Medium with at least two liquid crystalline components, characterized in that there is at least one contains liquid crystalline compound according to the invention, and a Liquid crystal display containing such a medium.  

Another object of the invention are from Liquid crystalline compounds prepared according to the invention Polymers and polymer networks as well as the use of Compounds, media and polymers according to the invention in Liquid crystal displays based on the principle of the twisted cell, the Guest-host effect, the effect of deformation erect Phases or static or dynamic scattering, continue in cholesteric or ferroelectric Liquid crystal displays or IPS (in plane switching), polymer gel or PDLC displays (polymer dispersed liquid crystal displays), electro-optical scattering cells, optical polarization or Compensation films, orientation layers, color filters or holographic elements, in photocrosslinkable adhesives, tensile fibers, liquid crystal pigments, colorants or Cosmetics, diagnostic applications, as Security markings, in non-linear optics and optical Data storage as well as dopants.

Particularly preferred compounds of the formula I are those of the formulas Ia to Ii

wherein R1, R2, Z and e have the meaning given in formula I,

each independently

G ² or T ² , and
L ¹ and L ² each independently mean H, F, CN, CI or unsubstituted or mono- or polysubstituted by F or CI alkyl, alkoxy or alkanoyl having 1 to 7 carbon atoms.

Compounds of the formulas Ia, Ib, Ic, Id, Ie are particularly preferred. If and Ig, in particular those of the formulas Ia, Ib and Ic.

L ¹ and L ^{2 are} preferably F, CI, CN, NO ₂ , CH ₃ , C ₂ H ₅ , OCH ₃ , OC ₂ H ₅ , COCH ₃ , COC ₂ H ₅ , CF ₃ , OCF ₃ , OCHF ₂ , OC ₂ F ₅ , in particular F, CI, CN, CH ₃ , C ₂ H ₅ , OCH ₃ , COCH ₃ and OCF ₃ , particularly preferably F, CI, CH ₃ , OCH ₃ and COCH ₃ .

The following are particularly preferred formulas for the group

listed. In these formulas, Phe means 1,4-phenylene, which can additionally be substituted in the 2-, 3- and / or 5-position by L ¹ as indicated above. Furthermore Pyd mean pyridine-2,5-diyl, pyr pyrimidine-2,5-diyl, Cyc 1,4-cyclohexylene, which can also be substituted in the 4-position by L ¹ and dio trans-1,3-dioxane-2 , 5-diyl. The heterocycles Pyd, Pyr and Dio each also include the possible positional isomers. Z in these formulas has one of the meanings given in formula I. The following list of preferred formulas also includes their mirror images.

-Phe- I 1-1

-Cyc- I 1-2

-Pyd- I 1-3

-Pyr- I 1-4

-Dio- I 1-5

-Phe-Z-Phe- I 2-1

-Cyc-Z-Phe- I 2-2

-Cyc-Z-Cyc- I 2-3

-Phe-Z-Pyd- I 2-4

-Phe-Z-Pyr- I 2-5

-Pyr-Z-Pyd- I 2-6

-Phe-Z-Dio- I 2-7

-Dio-Z-Dio- I 2-8

-Cyc-Z-Dio- I 2-10

-Phe-Z-Phe-Z-Phe- I 3-1

-Cyc-Z-Phe-Z-Phe- I 3-2

-Phe-Z-Cyc-Z-Phe- I 3-3

-Cyc-Z-Cyc-Z-Phe- I 3-4

-Cyc-Z-Phe-Z-Cyc- I 3-5

-Cyc-Z-Cyc-Z-Cyc- I 3-6

-Pyr-Z-Phe-Z-Phe- I 3-7

-Phe-Z-Pyr-Z-Phe- I 3-8

-Pyd-Z-Phe-Z-Phe- I 3-9

-Phe-Z-Pyd-Z-Phe- I 3-10

-Dio-Z-Phe-Z-Phe- I 3-11

-Phe-Z-Dio-Z-Phe- I 3-12

-Phe-Z-Phe-Z-Phe- I 3-13

-Dio-Z-Cyc-Z-Cyc- I 3-14

-Cyc-Z-Dio-Z-Cyc- I 3-15

-Dio-Z-Dio-Z-Cyc- I 3-16

The partial formulas I 1-1 to I 1-5 and I 2-1 to are particularly preferred I 2-10, in particular the sub-formulas I 1-1, I 1-2, I 2-1, I 2-2, 2-3 and I 2-4.

Z in the above-mentioned preferred formulas Ia to Ii and the sub-formulas in the series I 1, I 2 and I 3 preferably denotes -COO-, -OCO-, -CH ₂ CH ₂ -, -OCH ₂ -, -CH ₂ O- , -CH = CH-, -C∼C- or a single bond, in particular -COO-, -OCO-, -CH ₂ CH ₂ -, -C∼C- or a single bond.

If Phe is substituted 1,4-phenylene, this is preferably substituted one or more times by L ¹ according to one of the preferred meanings mentioned above. It is preferably 2- or 3-fluoro, 2,3-difluoro, 3,5-difluoro, 2- or 3-chloro, 2- or 3- methyl, 2,3-dimethyl, 2- or 3-methoxy-, 2- or 3-trifluoromethyl-, 2- or 3-trifluoromethoxy-, 2- or 3-methylcarbonyl-, 2- or 3- cyano- or 2,3-dicyano-1,4-phenylene. Substituted 1,4-cyclohexylene is preferably 4-cyano-1,4-cyclohexylene. For 1,4-cyclohexylene, the trans configuration is generally preferred.

Particular preference is given to compounds of the formula I in which R ¹ and R ² each independently of one another denote F, Cl, CN or unsubstituted or mono- or polysubstituted by fluorine-substituted alkyl, alkoxy or alkenyl having up to 12 carbon atoms.

Z ¹ to Z ⁵ in the compounds of the formula I particularly preferably each independently of one another are -COO-, -OCO-, -CH ₂ CH ₂ -, -OCH ₂ -, -CH ₂ O-, -CH = CH-, - C∼C or a single bond.

Furthermore, particular preference is given to compounds of the formula I in which at least one of the groups A ¹ to A ⁴ denotes a double-bonded chiral group G ² , and compounds in which R ¹ and / or R ² denotes a single-bonded chiral group G ¹ .

The chiral groups G ¹ and G ² are preferably sugar groups, sugar alcohols, sugar acids, lactic acids, chiral substituted glycols, steroid derivatives, terpene derivatives, amino acids or sequences of a few, preferably 1-5, amino acids.

Particularly preferred groups G ² are sugar derivatives such as, for example, glucose, mannose, galactose, fructose, arabinose, dextrose; Sugar alcohols such as sorbitol, mannitol, galactilo, or their anhydro derivatives such as isosorbide (1,4: 3,6-dianhydro-D-sorbide); Sugar acids such as gluconic acid, gulonic acid, ketogulonic acid; chiral substituted glycol residues such as mono- or oligoethylene or propylene glycols, in which one or more CH ₂ groups are substituted by alkyl or alkoxy; Amino acids such as alanine, valine, phenylglycine or phenylalanine, or sequences from 1 to 5 of these amino acids.

Particularly preferred groups G ¹ are steroid derivatives such as cholesteryl or cholic acid residues; Terpene derivatives such as, for example, menthyl, neomenthyl, campheyl, pineyl, terpineyl, isolongifolyl, fenchyl, carreyl, myrthenyl, nopyl, geraniyl, linaloyl, neryl, citronellyl, dihydrocitronellyl; Sugar acid residues; Lactic acid residues or monovalent derivatives of the structural elements G ² mentioned above.

Further particularly preferred compounds of the formula I are those in which at least one of the groups A ¹ to A ⁴ denotes a double-bonded chromophoric group T ² , and compounds in which R ¹ and / or R ² denotes a single-bonded chromophoric group T ¹ .

The chromophoric group T ² is preferably selected from the group comprising dyes such as, for example, azo-triphenylmethane, anthraquinone, cyanine, pyrrolo [3,4] pyrrole, indigo, fluorescein, rhodanine, thionine, oxazole, Benzimidazole or perylene dyes.

The chromophoric group T ¹ is preferably selected from the group containing dyes such as the monovalent derivatives of the dyes mentioned for T ² .

If R ¹ or R ² in the compounds of the formula I are an alkyl radical and / or an alkoxy radical, this can be straight-chain or branched. It is preferably straight-chain, has 2, 3, 4, 5, 6 or 7 carbon atoms and accordingly preferably means ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentoxy ,. Hexoxy or Heptoxy, furthermore methyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octoxy, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy or tetradecoxy.

Oxaalkyl preferably means straight-chain 2-oxapropyl (= Methoxymethyl), 2- (= ethoxymethyl) or 3-oxabutyl (= 2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or  7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.

If R ¹ or R ^{2 is} an alkyl radical in which a CH ₂ group has been replaced by -CH = CH-, this can be straight-chain or branched. It is preferably straight-chain and has 2 to 10 carbon atoms. Accordingly, it means especially vinyl, prop-1-, or prop-2-enyl, but-1-, 2- or but-3-enyl, pent-1-, 2-, 3- or pent-4-enyl, hex -1-, 2-, 3-, 4- or hex-5-enyl, hept-1-, 2-, 3-, 4-, 5- or hept-6-enyl, oct-1-, 2-, 3-, 4-, 5-, 6- or oct-7-enyl, non-1-, 2-, 3-, 4-, 5-, 6-, 7- or non-8-enyl, Dec-1 -, 2-, 3-, 4-, 5-, 6-, 7-, 8- or Dec-9-enyl.

Particularly preferred alkenyl groups are C ₂ -C ₇ -1E-alkenyl, C ₄ -C ₇ -3E-alkenyl, C ₅ -C ₇ -4-alkenyl, C ₆ -C ₇ -5-alkenyl and C ₇ -6-alkenyl , in particular C ₂ -C ₇ -1 E-alkenyl, C ₄ -C ₇ -3E-alkenyl and C ₅ -C ₇ -4-alkenyl. Examples of particularly preferred alkenyl groups are vinyl, 1 E-propenyl, 1 E-butenyl, 1 E-pentenyl, 1 E-hexenyl, 1 E-heptenyl, 3-butenyl, 3E-pentenyl, 3E-hexenyl, 3E-heptenyl, 4- Pentenyl, 4Z-hexenyl, 4E-hexenyl, 4Z-heptenyl, 5-hexenyl, 6-heptenyl and the like. Groups of up to 5 carbon atoms are generally preferred.

If R ¹ or R ^{2 is} an alkyl radical in which one CH ₂ group has been replaced by -O- and one has been replaced by -CO-, these are preferably adjacent. Thus, they include an acyloxy group -CO-O- or an oxycarbonyl group -O-CO-. These are preferably straight-chain and have 2 to 6 carbon atoms.

Accordingly, they mean especially acetyloxy, propionyloxy, Butyryloxy, pentanoyloxy, hexanoyloxy, acetyloxymethyl, Propionyloxymethyl, butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl, 2-propionyloxyethyl, 2-butyryloxyethyl, 3-acetyloxypropyl, 3-propionyloxypropyl, 4-acetyloxybutyl, Methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, Pentoxycarbonyl, methoxycarbonylmethyl, ethoxycarbonylmethyl, Propoxycarbonylmethyl, butoxycarbonylmethyl,  2- (methoxycarbonyl) ethyl, 2- (ethoxycarbonyl) ethyl, 2- (propoxy carbonyl) ethyl, 3- (methoxycarbonyl) propyl, 3- (ethoxycarbonyl) propyl, 4- (methoxycarbonyl) butyl.

If R ¹ or R ^{2 represent} an alkyl radical in which two or more CH ₂ groups have been replaced by -O- and / or -CO-O-, this can be straight-chain or branched. It is preferably branched and has 3 to 12 carbon atoms. Accordingly, it means especially bis-carboxy-methyl, 2,2-bis-carboxy-ethyl, 3,3-bis-carboxy-propyl, 4,4-bis-carboxy-butyl, 5,5-bis-carboxy-pentyl, 6,6-bis-carboxy-hexyl, 7,7-bis-carboxy-heptyl, 8,8-bis-carboxy-octyl, 9,9-bis-carboxy-nonyl, 10,10-bis-carboxy-decyl, Bis (methoxycarbonyl) methyl, 2,2-bis (methoxycarbonyl) ethyl, 3,3-bis (methoxycarbonyl) propyl, 4,4-bis (methoxycarbonyl) butyl, 5,5-bis (methoxycarbonyl) pentyl, 6,6-bis (methoxycarbonyl) hexyl, 7,7-bis (methoxycarbonyl) heptyl, 8,8-bis (methoxycarbonyl) octyl, bis (ethoxycarbonyl) methyl, 2,2-bis (ethoxycarbonyl) ethyl, 3,3-bis (ethoxycarbonyl) propyl, 4,4-bis (ethoxycarbonyl) butyl, 5,5-bis (ethoxycarbonyl) hexyl.

If R ¹ or R ^{2 is} an alkyl or alkenyl radical which is simply substituted by CN or CF ₃ , this radical is preferably straight-chain. The substitution by CN or CF ₃ is in any position.

If R ¹ or R ^{2 is} an alkyl or alkenyl radical which is at least monosubstituted by halogen, this radical is preferably straight-chain and halogen is preferably F or CI. In the case of multiple substitution, halogen is preferably F. The resulting residues also include perfluorinated residues. In the case of single substitution, the fluorine or chlorine substituent can be in any position, but preferably in the ω position. Examples of particularly preferred straight-chain groups with terminal fluorine are fluoromethyl, 2-fluoroethyl, 3-fluoropropyl, 4-fluorobutyl, 5-fluoropentyl, 6-fluorohexyl and 7-fluoroheptyl. However, other positions of the fluorine are not excluded.

Compounds of the formula I with branched wing groups R ¹ or R ² can occasionally be of importance because of their better solubility in the customary liquid-crystalline base materials, but in particular as chiral dopants if they are optically active. Smectic compounds of this type are suitable as components for ferroelectric materials.

Compounds of the formula I with S _A phases are suitable, for example, for thermally addressed displays.

Preferred chiral branched radicals R ¹ and R ² are 2-butyl (= 1-methylpropyl), 2-methylbutyl, 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, 2-octyl, in particular 2-methylbutyl, 2- methylbutoxy, 2-methylpentoxy, 3-methylpentoxy, 2-ethylhexoxy, 1-methylhexoxy, 2-octyloxy, 2-oxa-3-methylbutyl, 3-oxa-4-methylpentyl, 4-methylhexyl, 2-nonyl, 2- Decyl, 2-dodecyl, 6-methoxyoctoxy, 6-methyloctoxy, 6-methyloctanoyloxy, 5-methylheptyloxycarbonyl, 2-methylbutyryloxy, 3-methylvaleroyloxy, 4-methylhexanoyloxy, 2-chloropropionyloxy, 2-chloro-3-methylbutyryloxy, 2-chloro 4-methylvaleryloxy, 2-chloro-3-methylvaleryloxy, 2-methyl-3-oxapentyl, 2-methyl-3-oxahexyl, 1-methoxypropyl-2-oxy, 1-ethoxypropyl-2-oxy, 1-propoxypropyl-2- oxy, 1-butoxypropyl-2-oxy, 2-fluorooctyloxy, 2-fluorodecyloxy.

Compounds of the formula I containing achiral branched groups R ¹ or R ² can also be of importance as co-components in liquid-crystalline media, for example to suppress the tendency to crystallize. Branched groups of this type usually contain no more than one chain branch. Preferred achiral branched groups are, for example, isopropyl, isobutyl (= methyl propyl), isopentyl (= 3-methyl butyl), isopropoxy, 2-methyl propoxy and 3-methyl butoxy.

Compounds according to the invention which carry one or more polymerizable groups which are optionally connected to the mesogenic part of the molecule via a spacer group are likewise preferred, in particular compounds of the formula I in which at least one of the radicals R ¹ and R ² P- (Sp-X) _n means.

The polymerizable group P is preferably acrylic, Methacrylic, chloroacrylic, vinyl, vinyloxy, styryl, styryloxy or epoxy, especially acrylic, methacrylic, vinyloxy or epoxy.

All groups known for this purpose can be considered as spacer group Sp. Sp is preferably a straight-chain or branched alkylene (ie double-bonded alkyl) group with 1 to 20 C atoms, particularly preferably with 1 to 12 C atoms, in which one or more non-adjacent CH ₂ groups are also represented by -O-, -S-, -NH-, -N (CH ₃ ) -, -CO-, -O-CO-, -S-CO-, -O-COO-, -CO-S-, -CO-O-, -CH (halogen) -, -CH (CN) -, -CH = CH- or -C∼C- can be replaced.

Typical spacer groups Sp are, for example, - (CH ₂ ) _o -, - (CH ₂ CH ₂ O) _r -CH ₂ CH ₂ -, -CH ₂ CH ₂ -S-CH ₂ CH ₂ - or -CH ₂ CH ₂ -NH -CH ₂ CH ₂ -, wherein o is 2 to 12 and r is 1 to 3.

Preferred spacer groups Sp are, for example, ethylene, Propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, Decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, Methyleneoxybutylene, ethylene thioethylene, ethylene N-methyl iminoethylene, 1-methylalkylene, ethenylene, propenylene and Butenylene.

Compounds according to the invention are particularly preferred Formula I wherein Sp is an alkyl or alkoxy group with 2 to 6 carbon atoms Atoms means. Straight chain groups are particularly preferred.

In a further preferred embodiment, the compounds of the formula I contain at least one chiral spacer group Sp, in particular one chiral spacer group of the following formula:

wherein
Q ¹ and Q ² each independently of one another alkylene or alkyleneoxy having 1 to 10 carbon atoms, in which one or more CH ₂ groups are also represented by -O-, -S-, -NH-, -N (CH ₃ ) -, -C0-, -COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, -CH = CH- or -C∼C- can be replaced so that O- and / or S atoms are not directly linked to one another, which can optionally also be substituted one or more times by F, CI or CN,
Q ^{3 is} halogen, CN or alkyl or alkoxy having 1 to 4 carbon atoms other than Q ¹ and Q ² .

In compounds of the formula I in which R ¹ and R ^{2 are} simultaneously P- (Sp-X) _n -, the two spacer groups Sp and / or the two polymerizable groups P can be identical or different.

The formation of the mesogenic intermediate member B and the Presentation of the new liquid crystalline compounds that the Intermediate link B included, is done by procedures that are not for Liquid-crystalline analogs have been described, such as. B. in T. Wakabayashi et al., Tetrahedron Lett. 36, 5585 (1995) and L.A. Miller, C.A. 61, 9405 h, 1964.

According to these processes, either methyl propionate with various organic carboxylic acids in the presence of a mixed metal sulfide-cubane type cluster complex of the structure [PdMo ₃ S ₄ (tacn) ₃ CI] [PF ₆ ] ₃ (tacn = 1,4,7-triazacyclononane) or methyl propiolate in the presence of weakly basic (e.g. pyridine) or weakly acidic (e.g. Fe-III-acetate) catalysts with acetic acid, benzoic acid, acrylic acid, 2-naphthalene carboxylic acid or 9-fluorenecarboxylic acid in the sense of Michael addition to the corresponding acyloxyacrylates.

This transformation is now surprisingly also possible with the structurally complex carboxylic acids and propiolates, which as Key reaction to the liquid crystalline according to the invention Compounds of formula I leads.

Because of the mild reaction conditions, the Pd / Mo-catalyzed reaction leads to Z (cis) acyloxyacrylate, but this is done by increasing the base addition (e.g. NEt ₃ , pyridine) and the temperature (e.g. from 40 ° C to 80 ° C) is convertible into the E (trans) isomer.

For example, compounds of the formula I according to the invention, in which Z ³ denotes a structural element M 'with m = 1, are obtained if a carboxylic acid of the formula Ib is reacted with a propiolate of the formula Ia1 according to the following scheme.

The preparation of the precursors of the formula Ib is achieved using classic methods known in liquid crystal chemistry. The synthesis of the propiolic acid esters Ia1 is carried out from propiolic acid (propargyl acid) HC∼C-COOH and the corresponding alcohols R ¹ -Z ¹ - (A ¹ ) _a Z ² - (A ²⁾ _b -OH (which in turn can also be prepared by conventional methods ) z. B. using dicyclohexylcarbodiimide as a dehydrating agent.

Compounds of the formula I in which Z ³ denotes a structural element M 'with n = 2 are obtained if the propiolate of the formula Ia1 is reacted again with propiolic acid, the carboxyl group of the propiolic acid being added to the C∼C triple bond of the propiolate Ia1 , and the resulting product of formula Ia2

R ¹ -Z ¹ - (A ¹ ) _c -Z ² - (A ² ) _d -OOC-CH = CH-OOC-C∼CH Ia2

with the carboxylic acid of formula 1b as described above Brings reaction.

To prepare compounds of the formula I in which Z ^{3 is} a structural element M 'with n = 3, the propiolate of the formula Ia2 is reacted again in an analogous manner with propiolic acid, and the resulting intermediate is reacted with the acid of the formula Ib.

In analogy to the syntheses described above, structurally inverse compounds are prepared in which Z ³ denotes a structural element M "with m = 1, 2 or 3 by the radicals R ¹ -Z ¹ - (A ¹ ) _c -Z ² - (A ² ) _d - and - (A ³ ) _e -Z ⁴ - (A ⁴ ) _f -Z ⁵ -R ² in the formulas described above for the precursors and intermediates interchanged.

Another possibility for the synthesis of the liquid-crystalline compounds according to the invention is that first z. B. p-hydroxybenzoic acid with a propiolate z. B. the formula Ia to the product

converts the free hydroxy group of the product with propiolic acid esterified and the resulting product then another Subjects reaction with the propiolate of the formula Ia.  

In analogy to the reaction described above, instead of p-hydroxy-benzoic acid, for example, a hydroxycarboxylic acid of the formula Ie

HO- (A ¹ ) _b -COOH Ie

are used, from which the product of the formula Ie1, by esterification of the product by single or multiple reaction with propiolic acid. Hydroxyl group with propiolic acid the product of the formula Ie2, or the product of the formula Ie3 is formed by both of the reactions mentioned above,

HO- (A ² ) _b -COO- (CH = CH-COO) _m-1 -H Ie1

H- (C∼C-COO) _m-1 -O- (A ² ) _b -COOH Ie2

H- (C∼C-COO) _m-1 -O- (A ² ) _b -COO- (CH = CH-COO) _m-1 -H Ie3

From these intermediates can be implemented with Compounds of the formulas Ia1, Ib, Ia2 or structurally analogous Connections in the manner described above Formula I are prepared, the order of each Reaction steps can be chosen arbitrarily.

Further production possibilities for compounds of the formula I result from the esterification of hydroquinone or generally dihydroxy compounds of the formula If

HO- (A ² ) _b -OH If

with propiolic acid or propiolic acid derivatives of the formula Ib, or by double addition of propiolic acid or propiolic acid derivatives of the formula Ia to terephthalic acid or generally to dicarboxylic acids of the formula Ig

HOOC- (A ² ) _b -COOH Ig

In the reaction descriptions set out above, R ¹ , R ² , A ¹ to A ⁴ , Z ¹ to Z ⁵ and a, b, c, d and m have the meaning given in formula I.

In principle, the compounds according to the invention which carry polymerizable groups are synthesized as described above. It may be advantageous to convert the reactive groups -OH, -NH ₂ , -COOH, -CH = CH ₂ during the synthesis in a protected form and then to remove the protective groups, or to introduce these reactive groups only in the last reaction step.

Linking the intermediate link M 'or M "with chiral and Chromophore groups are also analogous to those above methods mentioned.

The known methods mentioned above e.g. B. to represent the Precursors of formula Ib or to introduce and split off Protection groups are in the literature (e.g. in the standard works such as Houben-Weyl, Methods of Organic Chemistry, Georg-Thieme- Verlag, Stuttgart), namely under Reaction conditions known for the reactions mentioned and are suitable. You can also use known, Make use of variants not mentioned here.

Further display methods can be found in the following Examples.

The compounds of the invention are also suitable for Use as components of liquid crystalline media. Liquid-crystalline media according to the invention preferably contain in addition to one or more compounds of the invention Formula I as further constituents 2 to 40, in particular 4 to 30 Components. These media contain very particularly preferably in addition to one or more compounds 7 to  25 components. These other ingredients are preferred selected from nematic or nematogenic (monotropic or isotropic) substances, especially substances from the classes the azoxybenzenes, benzylidene anilines, biphenyfe, terphenyls, Phenyl or cyclohexyl benzoates, cyclohexane carboxylic acid phenyl or cyclohexyl ester, phenyl or cyclohexyl ester of cyclo hexylbenzoic acid, phenyl or cyclohexyl ester of cyclo hexylcyclohexane carboxylic acid, cyclohexyl phenyl ester of Benzoic acid, cyclohexane carboxylic acid, or cyclohexyl cyclohexane carboxylic acid, phenylcyclohexane, cyclohexylbiphenyl, Phenylcyclohexylcyclohexane, cyclohexylcyclohexane, cyclo hexylcyclohexylcyclohexenes, 1,4-bis-cyclohexylbenzenes, 4,4'-bis cycio-hexylbiphenyie, phenyl- or cyclohexylpyrimidines, phenyl- or cyclohexylpyridines, phenyl- or cyclohexyldioxanes, phenyl- or cyclohexyl-1,3-dithiane, 1,2-diphenylethane, 1,2-dicyclohexyl ethane, 1-phenyl-2-cyclohexylethane, 1-cyclohexyl-2- (4-phenyl cyclohexyl) ethane, 1-cyclohexyl-2-biphenyiylethane, 1-phenyl 2-cyclohexyl-phenylethanes, optionally halogenated stilbenes, Benzylphenyl ether, tolanes and substituted cinnamic acids. The 1,4- Phenylene groups in these compounds can also be fluorinated.

The most important compounds which are suitable as further constituents of media according to the invention can be characterized by the formulas 1, 2, 3, 4 and 5:

R'-LER "1

R'-L-COO-ER "2nd

R'-L-OOC-ER "3

R'-L-CH ₂ CH ₂ -ER "4

R'-L-C∼C-E-R "5

In formulas 1, 2, 3, 4 and 5, L and E are the same as or can be different, each independently one bivalent residue from the from -Phe-, -Cyc-, -Phe-Phe-, -Phe-Cyc-, Cyc-Cyc-, -Pyr-, -Dio-, -G-Phe- and -G-Cyc- as well as their Mirror images formed group, where Phe unsubstituted or  1,4-Phenyien substituted by fluorine, Cyc trans-1,4-cyclohexylene or 1,4-cyclohexylene, pyr pyrimidine-2,5-diyl or pyridine-2,5-diyl, Dio 1,3-dioxane-2,5-diyl and G 2- (trans-1,4-cyclohexyl) ethyl, Pyrimidine-2,5-diyl, pyridine-2,5-diyl or 1,3-dioxane-2,5-diyl.

One of the radicals L and E is preferably Cyc, Phe or Pyr. E is preferably Cyc, Phe or Phe-Cyc. Preferably contain the media according to the invention one or more components selected from the compounds of the formulas 1, 2, 3, 4 and 5, wherein L and E are selected from the group Cyc, Phe and Pyr and selected one or more components at the same time the compounds of formulas 1, 2, 3, 4 and 5, wherein one of the Residues L and E is selected from the group Cyc, Phe and Pyr and the other residue is selected from the group -Phe-Phe-, Phe-Cyc-, -Cyc-Cyc-, -G-Phe- and -G-Cyc-, and optionally one or more components selected from the compounds of the formulas 1, 2, 3, 4 and 5, in which the radicals L and E are selected are from the group -Phe-Cyc-, -Cyc-Cyc-, -G-Phe- and -G-Cyc-.

R 'and R "mean in a smaller subset of the compounds of the formulas 1, 2, 3, 4 and 5 each independently of one another alkyl, Alkenyl, alkoxy, alkoxyalkyl, alkenyloxy or alkanoyloxy with up to 8 carbon atoms. The following is this smaller subset Group A and the compounds are called with the sub-formulas 1a, 2a, 3a, 4a and 5a. Most of these Compounds R 'and R "are different from each other, one these radicals are mostly alkyl, alkenyl, alkoxy or alkoxyalkyl.

In another smaller subgroup, referred to as group B, of the compounds of the formulas 1, 2, 3, 4 and 5, R "-F, -C1, NCS or - (O) _i CH ₃ - _{(k + l)} F _k Cl _l , where i is 0 or 1 and k + I, 1, 2 or 3; the compounds in which R "has this meaning are denoted by the sub-formulas 1b, 2b, 3b, 4b and 5b. Particularly preferred are those compounds of the sub-formulas 1b, 2b, 3b, 4b and 5b in which R "has the meaning -F, -Cl, -NCS, -CF ₃ , -OCHF ₂ or -OCF ₃ .

In the compounds of sub-formulas 1b, 2b, 3b, 4b and 5b, R 'has that meaning given for the compounds of the sub-formulas 1a-5a and is preferably alkyl, alkenyl, alkoxy or alkoxyalkyl.

In another smaller subset of the compounds of the Formulas 1, 2, 3, 4 and 5 mean R "-CN; this subgroup is described in hereinafter referred to as group C and the compounds of these Subgroups are accordingly with sub-formulas 1c, 2c, 3c, 4c and 5c. In the compounds of sub-formulas 1c, 2c, 3c, 4c and 5c has R 'that in the compounds of sub-formulas 1a-5a indicated meaning and is preferably alkyl, alkoxy or Alkenyl.

In addition to the preferred compounds of groups A, B and C. also other compounds of the formulas 1, 2, 3, 4 and 5 with others Variants of the proposed substituents are common. All these Substances are based on methods known from the literature or in analogy available for this.

In addition to the compounds of the formula I, the media according to the invention preferably contain one or more compounds which are selected from group A and / or group B and / or group C. The mass fractions of the compounds from these groups in the media according to the invention are preferred

Group A: 0 to 90%, preferably 20 to 90%, in particular 30 to 90%
Group B: 0 to 80%, preferably 10 to 80%, in particular 10 to 65%
Group C: 0 to 80%, preferably 5 to 80%, in particular 5 to 50%

where the sum of the mass fractions of each Media contained compounds from the  Groups A and / or B and / or C preferably 5% to 90% and is in particular 10% to 90%.

The media according to the invention preferably contain 1 to 40%, particularly preferably 5 to 30% of compounds of the formula I. Media containing more than 40% are also preferred. in particular 45 to 90% of compounds of formula I. The media preferably contain 1 to 5, particularly preferably 2, 3, 4 or 5 Compounds of formula I.

The production of the liquid crystal which can be used according to the invention Mixtures are carried out in a conventional manner. As a rule, the desired amount of those used in smaller quantities Components in the main constituent Components dissolved, expediently at elevated temperature. It is also possible solutions of the components in an organic Solvents, e.g. B. in acetone, chloroform or methanol mix and the solvent after mixing again remove, for example by distillation.

The liquid-crystal media can also be used by those skilled in the art contain known additives described in the literature. For example, 0-15% 10 pleochroic dyes or chiral dopants are added.

The manufacture of liquid crystalline polymers and copolymers the compounds according to the invention are obtained by polymerization, Copolymerization or polymer-analogous implementation according to known Procedure carried out.

Liquid-crystalline polymers according to the invention are preferred, Copolymers or (co) polymer networks that have one or more have mesogenic groups in the main polymer chain.

Also preferred are liquid-crystalline polymers according to the invention, Copolymers or (co) polymer networks that have one or more  have linked side chains of the polymer main chain, which contain one or more mesogenic groups.

Compounds according to the invention with one or more polymerizable groups, in particular those of the formula I which carry a terminal vinylogous CH ₂ = CH group or epoxy group, can, for. B. by free radical, anionic or cationic polymerization, optionally together with suitable comonomers, can be polymerized (co) by the known processes to give liquid-crystalline side-chain polymers.

Compounds containing two or more of these polymerizable groups have, can be implemented directly to polymer networks.

Compounds according to the invention which as polymerizable groups z. B. terminal -OH, -COOH or -NH ₂ groups can, optionally together with suitable comonomers, be polymerized (poly) by condensation to liquid-crystalline main chain polymers.

Compounds according to the invention as polymerizable groups e.g. B. can carry terminal N = C = O or HC∼CH-COO groups, optionally together with suitable comonomers, by polyaddition liquid crystalline main chain polymers (co) are polymerized.

In addition, compounds of the invention, the z. B. carry a terminal CH ₂ = CH, HO, H ₂ N, HOOC, N = C = O, HC∼CH-COO or epoxy group, by polymer-analogous reaction with a corresponding reactive group-containing polymer backbone be linked.

From compounds according to the invention that are polymerizable Groups contain two terminal propinoyl groups CH∼C-COO-, can e.g. B. directly by liquid addition with dicarboxylic acids Main chain polymers are made. Here are the above mentioned, e.g. B. in T. Wakabayashi et al., Tetrahedron Lett. 36, 5585 (1995) and L.A. Miller, C.A. 61, 9405 h, 1964, catalysts  proven. In polymer represented by Pd / Mo catalysis, under forms mild, non-isomerizing conditions the group M in the Z- Configuration off.

Analogously, liquid-crystalline main chain polymers can be made from Compounds according to the invention that as polymerizable Groups a terminal propinoyl groups CH∼C-COO- and one contain terminal HOOC group, produced by polyaddition become.

The application thus further relates to a process for the preparation of oligomeric or polymeric liquid-crystalline compounds comprising at least one structural element of the formula M 'or M "by:

• 1. a *) one or more compounds of formula 1, wherein R ¹ and / or R ² P- (Sp-X) _n - and P each independently
  CH∼C-COO-, CH ₂ = CW-COO-, WCH = CH-O-,
  or CH ₂ = CH-phenyl- (O) _k -, where WH, CH ₃ or Cl and k is 0 or 1, mean radical, optionally in the presence of one or more further polymerizable compounds which have at least one polymerizable group, cationically or anionically (co-) polymerized,

or

• 1. b *) one or more compounds of the formula I in which R ¹ and R ² P- (Sp-X) _n- and P are each independently CH∼C-COO-, N = C = O-, H ₂ N- , HO, HOOC or HS, optionally in the presence of one or more further compounds which have at least two groups which are suitable for reaction with the abovementioned groups P, copolymerized by polycondensation or polyaddition,

or

• 1. c *) one or more compounds of the formula I, in which R ¹ and / or R ² P- (Sp-X) _n - and P are each independently of one another
  CH∼C-COO-, CH ₂ = CW-COO-, WCH = CH-O-,
  CH ₂ = CH-phenyl- (O) _k -, N = C = O-, H ₂ N-, HO-, HOOC- or HS-, where WH, CH ₃ or Cl and k is 0 or 1, by polymer-analogous reaction to a polymer main chain, such as, for example, a polyhydrogensiloxane, a polyol, a polyacid, a polyamine or a polyamide, optionally in the presence of one or more further compounds which have at least one group suitable for polymer-analogous reaction with the abovementioned polymer main chains .

A further preferred embodiment of the invention is directed to oligomeric and polymeric liquid-crystalline compounds containing at least one structural element of the formula M 'or M ", which are prepared from polymerizable compounds of the formula II

HC∼C-COO- (Sp-X) _n -Z ¹ - (A ¹ ) _a -Z ² - (A ² ) _b -Z ³ - (A ³ ) _c -Z ⁴ (A ⁴ ) _d -Z ⁵ -R ¹ II

wherein Sp, X, n, A ¹ to A ⁴ , a, b, c, d and R ¹ each independently have one of the meanings given in formula I, and Z ¹ to Z ⁵ each independently of one another for Z in formula I have the meanings given, by copolymerizing one or more compounds of the formula II, in which R ^{1 is} P- (Sp-X) _n and P HOOC-, in accordance with b *), or one or more compounds of the formula II in accordance with c *) added to a polyacid,
or

• 1. d *) one or more compounds of the formula II in which R ^{1 is} P- (Sp-X) _n and P is HC∼C-COO-, copolymerized with one or more dicarboxyl compounds of the formula HOOC- (U) _u COOH, optionally in the presence of one or more further compounds which have at least two groups which are suitable for reaction with the dicarboxyl compounds and / or the compounds of the formula II,
  where u is 0 or 1 and U each independently represents a divalent aliphatic, iso- or heterocycloaliphatic or iso- or heteroaromatic group, which can also be substituted.

The compounds of formula II are new and are another Subject of the invention.

Particularly preferred compounds of the formula II are those of the following sub-formulas

HC∼C-COO- (Sp-X) _n -Z ¹ -A ¹ -Z ² -A ² -R ¹ II-1

HC∼C-COO- (Sp-X) _n Z ¹ -A ¹ -Z ² -A ² -Z ³ -A ³ -R ¹ II-2

HC∼C-COO- (Sp-X) _n Z ¹ -A ¹ -Z ² -A ² -Z ³ -A ³ -Z ⁴ -A ⁴ II-3

wherein Sp, X, n, A ¹ to A ⁴ , Z ¹ to Z ⁴ and R ^{1 have} the meaning given in formula II, in particular those in which A ¹ , A ² , A ³ and A ^{4 are} each independently of one another

as defined above mean.

Particularly preferred are compounds of the formula II-1, in which -A ¹ -Z ² - A ² - is selected from the preferred formulas I 2-1 to I 2-10, and compounds of the formula II-2, in which -A ¹ - Z ² -A ² -Z ³ -A ³ - is selected from the preferred formulas I 3-1 to I 3-16.

Furthermore, oligomers and polymers according to the invention can be produced by (co) polymerizing a polymerizable liquid-crystalline mixture comprising the following components

• A) one or more compounds of formula I with one or several polymerizable groups,
• B) at least one initiator component,
• C) optionally one or more further polymerizable mesogenic or non-mesogenic compounds,
• D) optionally one or more non-polymerizable mesogenic compounds,
• E) optionally one or more chiral dopants.

The above polymerizable liquid crystalline Mixtures are new and another object of the invention.

Suitable polymerizable mesogenic compounds of the Component C) as comonomers together with the compounds of the invention can be polymerized, are described for example in WO 93/22397; EP 0,261,712; DE 195.04.224; WO 95/22586 or WO 97/00600. The ones disclosed therein However, connections are only intended as examples, without the To limit the subject of the present invention.

Typical examples of compounds of the formula V are those from the following list, which is intended to further illustrate the object of the present invention without restricting it:

In these compounds, x and y each independently represent 1 to 12, B 1,4-phenylene or 1; 4-cyclohexylene, R ⁰ F, Cl, CN or alkyl or alkoxy having 1 to 12 C atoms, which is optionally substituted one or more times by F or Cl, and L ¹ and L ² each independently of one another H, F, Cl , CN, or unsubstituted or mono- or polysubstituted by F or Cl alkyl, alkoxy or alkanoyl having 1 to 7 carbon atoms.

The polymerizable compounds of formula V can by well-known methods can be produced in standard works organic chemistry such as Houben-Weyl, Methods of organic chemistry, Thieme-Verlag, Stuttgart are described. Other manufacturing methods can be found e.g. B. in the publications cited above WO 93/22397; EP 0 261 712; DE 195.04.224; WO 95/22586 and WO 97/00600.

The polymerizable used in components A) and C) Compounds are preferably mono- or bifunctional, i.e. H. she have one or two polymerizable functional groups.

The polymerizable liquid crystallines according to the invention Mixtures can be in addition or as an alternative to the chiral polymerizable compounds also one or more not contain polymerizable chiral compounds which are mesogenic or can be non-mesogenic. For example, are suitable for this commercially available dopants, such as. B. R 811 or R 1011 (Merck KGaA, Darmstadt).

The polymerizable liquid crystallines according to the invention Mixtures can be used in addition to the above components other components such as catalysts, Sensitizers, stabilizers, co-reactive monomers or Contain surface-active substances.

To increase the cross-link density during production Contain liquid crystalline polymer networks according to the invention the mixtures according to the invention additionally or alternatively the mesogenic polymerizable compounds preferably up to 20% of a non-mesogenic compound with two or more polymerizable groups (bi- or multifunctional Links).

Typical examples of bifunctional non-mesogenic compounds are alkyl diacrylates or alkyl dimethacrylates with alkyl groups with 1  up to 20 carbon atoms. Typical examples of multifunctional are not Mesogenic compounds with are trimethylpropane trimethacrylate or pentaerythritol tetraacrylate.

Liquid crystalline polymers can be obtained from the inventive polymerizable mixtures e.g. B. by solution polymerization or bulk polymerization according to the methods known for this getting produced.

For example, a mixture according to the invention radical solution polymerization in a solvent such as Dichloromethane, tetrahydrofuran or toluene in the presence of one Initiators like AIBN by heating at 30 to 60 ° C for 24 hours be polymerized.

A particularly preferred method of representation is liquid crystalline polymers, polymer networks and polymer gels the in-situ photopolymerization of polymerizable mixtures in Presence of suitable photoinitiators. Suitable for this compounds according to the invention, which one or have several acrylic, methacrylic, epoxy or vinyloxy groups, especially those of the formula I and II.

For this purpose, the polymerizable mixtures preferably applied to a substrate, oriented and by Radiation z. B. polymerized with UV light or networked. A general description of this method can be found in the literature, for example in D. J. Broer et al., Makromol.Chem. 190, 225 pff. and 3202ff. (1989).

Suitable substrates are, for example, glass plates or Plastic substrates such as B. Polyethylene terephthalate (PET) films, Polyvinyl alcohol (PVA), polycarbonate (PC) or triacetyl cellulose (TAC).  

Suitable initiators are e.g. B. those when heated or Radiation decays to free radicals or ions, which the Start polymerization.

As radical photoinitiators such. B. the commercial available Irgacure 651, Irgacure 184, Darocure 1173 or Darocure 4205 (Ciba Geigy AG), as cationic photoinitiators e.g. B. UVI 6974 (Union Carbide).

The polymerizable liquid-crystalline mixture according to the invention preferably contains 0.01 to 10%, in particular 0.05 to 8%, very particularly preferably 0.1 to 5% of an initiator component, preferably a UV photoinitiator.

A uniform orientation of the polymerizable liquid-crystalline mixture can be achieved by mechanical forces, such as. B. scissors, or by applying an electrical or magnetic field. In some cases the mixture is already applied, e.g. B. by doctoring, oriented on the substrate. Furthermore, in order to achieve or improve the uniform orientation of the mixture, the substrate can be provided with an orientation layer, for example made of rubbed polyimide or SiO _x , or the applied mixture can be covered with a second substrate, additional orientation effects or shear forces being able to occur.

The compounds, oligomers, polymers, Copolymers, (co-) polymer mills and mixtures are suitable for Use in liquid crystal displays, optical and electro-optical Components, electro-optical scatter cells, optical polarization or compensation films, orientation layers, color filters or holographic elements, photocrosslinkable adhesives, tensile Fibers, liquid crystalline pigments, colorants or cosmetics, diagnostic applications, as security markings, in the nonlinear optics and optical data storage.  

Compounds according to the invention which have one or more chiral Have groups are suitable for. B. for use in thermochromic polymerizable liquid crystalline mixtures, in Security markings, liquid crystalline colorants or as chiral Dopants.

The following examples are intended to illustrate the invention without limiting it. Unless otherwise stated, all percentages above and below mean percentages by weight; all temperatures are given in degrees Celsius. Δn denotes the optical anisotropy and n _o the ordinary refractive index (each at 589 nm and 20 ° C). Δε denotes the dielectric anisotropy and ε _┴ the dielectric constant perpendicular to the _longitudinal axis of the molecule.

The following abbreviations are also used:
K = crystalline, N = nematic, S = smectic, I = isotropic, the numbers between these symbols indicate the phase transition temperatures in ° C.
DCC = dicyclohexylcarbodiimide
DMAP = N, N-dimethylaminopyridine

example 1 Preparation of 4-propylphenyl propiolate

To a solution of 27.2 g n-propylphenol, 45.6 g DCC and 0.88 g DMAP in 500 ml of toluene with cooling 12.4 ml of propiolic acid added dropwise so that the temperature is a maximum of 30 ° C. To The strongly exothermic reaction phase will subside dark brown reaction mixture stirred overnight. Subsequently 4 g of oxalic acid are added, the mixture is stirred for 2 hours, from aspirated dicyclohexylurea sucked off and evaporated. The The residue is washed with toluene over silica gel (7729) through a frit given and rotated. The crude product (41.8 g, crude yield 100 %) will be implemented immediately.

Example 2 Preparation of 4-cyanophenyl propiolate

In analogy to Example 1, 119.1 g of 4-hydroxybenzonitrile are added 61.6 ml propiolic acid in the presence of 227.0 g DCC, 2.2 g DMAP and 20 g of oxalic acid. After working up according to Example 1 56.1 g of crude product are obtained, which is directly reacted further.

Example 3 Preparation of 3-fluoro-4-cyanophenyl propiolate

Analogously to Example 1, 27.4 g of 2-fluoro-4-hydroxybenzonitrile with 12.4 ml propiolic acid in the presence of 45.6 g DCC, 0.88 g DMAP and 4 g of oxalic acid. After working up according to Example 1 29.5 g of bright crystals are obtained, which are directly reacted further.  

Example 4 Preparation of 4-cyano-3,5-difluorophenyl propiolate

In analogy to Example 1, 77.6 g of 2,6-difluoro-4- hydroxybenzonitrile with 30.8 ml propiolic acid in the presence of 114 g DCC, 2.2 g DMAP and 10 g oxalic acid reacted. To Working up according to Example 1 gives 103.6 g of crude product directly implemented.

Example 5 Preparation of 3,4,5-trifluorophenyl propiolate

In analogy to Example 1, 110.5 g of 3,4,5-trifluorophenol are added 30.8 ml propiolic acid in the presence of 114 g DCC, 2.2 g DMAP and 10 g of oxalic acid reacted. After working up according to Example 1 100 g of crude product are obtained, which is directly implemented further.

Example 6 Preparation of 4-trifluoromethoxyphenyl propiolate

In analogy to Example 1, 53.4 g of 4-trifluoromethoxyphenoi with 18.5 ml propiolic acid in the presence of 68.4 g DCC, 1.32 g DMAP and 6 g of oxalic acid reacted. After working up according to Example 1 69 g of crude product are obtained, which is directly implemented further.

Example 7 Preparation of propiolic acid 2,3-difluoro-4-ethoxyphenyl ester

Analogously to Example 1, 91.6 g of 2,3-difluoro-4-ethoxyphenol with 30.8 ml propiolic acid in the presence of 113.5 g DCC, 1.1 g DMAP and 10 g of oxalic acid reacted. After working up according to Example 1 116 g of crude product are obtained, which is directly implemented further.  

Example 8 Preparation of propiolic acid (trans-4-propyl) cyclohexyl ester

Analogously to Example 1, 28.4 g of trans-4-propylcyclohexanol with 12.4 ml propiolic acid in the presence of 45.6 g DCC, 0.88 g DMAP and 4 g of oxalic acid. After working up according to Example 1 38.3 g of crude product are obtained, which is directly reacted further.

Example 9

16.8 g of the product from Example 1 together with 14.6 g of 4- Propylbenzoic acid, 0.9 ml pyridine and 70 ml toluene for 6 hours Stirred 120 ° C. Then it is cooled to room temperature and rotated in. The residue is washed with toluene over silica gel (7729) fritted and the eluate rotated in. The resulting yellow oil becomes at -20 ° C from 50 ml isopropanol and then at -20 ° C 50 ml of recrystallized hexane. The yellow crystals obtained are fritted again with toluene / heptane 1: 1 over silica gel (7729) and rotated in. The residue is extracted at a ratio of 1: 3 at -20 ° C Recrystallized hexane. Compound (9) is obtained in one yield of 16 g (51% of theory). Phase behavior: K 57 N 89.2 I; Δε = 7.8; Δn = 0.160.

The following connections are made in analogy to this

In the following table, Phe = 1,4-phenylene, Cyc = trans-1,4-cyclohexylene, Phe.F = 3-fluoro-1,4-phenylene, Phe.F. F = 3,5-difluoro-1,4-phenylene, PheFF = 2,3-difluoro-1,4-phenylene and Chol = cholesteryl. Unless otherwise noted, alkyl and alkoxy are straight-chain groups.

Example 10

Analogously to Example 9, 16.0 g of the product from Example 1 are reacted with 6.4 ml of propionic acid and 0.9 ml of pyridine in 70 ml of toluene. After working up as described in Example 9, compound (10) is obtained in a yield of 4.4 g (20% of theory).
Phase behavior K 75 N 105.8 I, Δε = 1.54, Δn = 0.139

Example 11

51.1 ml ethyl propiolate, 82.1 g 4-propylbenzoic acid and 5 ml of pyridine are refluxed in 375 ml of toluene for 2 hours and then stirred overnight at 100 ° C. The The reaction mixture is spun in and the residue in the ratio 1: 2 recrystallized from isopropanol at -20 ° C. For cleaning recrystallized from 160 ml isopropanol, then over with toluene Fritted silica gel (7729) and again after spinning in the eluate recrystallized from 120 ml pentane at -20 ° C. You get connection (11) in a yield of 63.7 g (49.4% of theory).

The following connections are made in analogy to this

In the following table, Phe = 1,4-phenylene, Cyc = trans- 1,4-cyclohexylene. Alkyl and alkxoy mean straight-chain groups, unless otherwise noted.  

Example 12

Analogously to Example 11, 19.2 g of propiolic acid 4- trifluoromethoxyphenyl ester from Example 6 with 19.9 g of 4- (4'- Propylphenyl-) benzoic acid and 0.75 ml pyridine in 70 ml toluene implemented. After working up as described in Example 11 compound (12) in a yield of 10.3 g (26.4% of theory).

The following connections are made in analogy to this.

In the following table, Phe = 1,4-phenylene, Cyc = trans-1,4-cyclohexylene, Phe.F = 3-fluoro-1,4-phenylene, Phe.FF = 3,5-difluoro-1,4 -phenylene and PheFF = 2,3-difluoro-1,4-phenylene. Unless otherwise noted, alkyl and alkoxy are straight-chain groups.

Claims (18)

1. Liquid-crystalline compounds, characterized in that they have at least one structural element of the formula M 'or their mirror image M "
where m is 1, 2 or 3. 2. Liquid crystalline compounds according to claim 1 of formula I.
R ¹ -Z ¹ - (A ¹ ) _a -Z ² - (A ² ) _b -Z ³ - (A ³ ) _c -Z ⁵ - (A ⁴ ) _d -Z ⁵ -R ² I
where the individual radicals have the following meaning
A ¹ to A ⁴ each independently of one another -A- (ZB) _e -, a double-bonded chiral structural element G ² or a double-bonded chromophoric group T ² ,
A and B are each independently 1,4-phenylene, in which one or two CH groups can also be replaced by N, trans-1,4-cyclohexylene, in which one or two CH ₂ groups can also be replaced by O and / or S. may be trans-1,4-cyclohexenylene, 1,4-bicyclo (2, 2, 2) octylene, naphthalene-2,6-diyl, piperidine-1,4-diyl, decahydronaphthalene-2,6-diyl, 1 , 2,3,4-tetrahydronaphthalene-2,6-diyl, cyclobutane-1,3-diyl, or, in these groups also 1 to 4 H atoms by F, Cl, CN, NO ₂ or unsubstituted or mono- or can be substituted several times by F or Cl substituted alkyl, alkoxy or alkanoyl with 1 to 7 C atoms,
Z each independently of one another -N = N-, -N = N (O) -, -CH = N-, -COO-, -OCO-, -CH ₂ CH ₂ -, - (CH ₂ ) 4-, -OCH ₂ -, CH ₂ O-, -CX ¹ = CX ² -, -CH ₂ -CH = CH-CH ₂ -, -CH = CH-COO-, OOC-CH = CH-, -C∼C-, - C∼C-COO-, -OOC-C∼C- COO- or a single bond,
e 0, 1 or 2,
Z ¹ to Z ⁵ each independently of one another have one of the meanings given for Z, M 'or M ",
a, b, c and d are each independently 0, 1 or 2, the sum a + b + c + d having to be different from 0,
R ^{1 is} H, F, Cl, CN, NO ₂ , NCS, straight-chain or branched alkyl having 1 to 25 C atoms, in which also one or more CH ₂ groups are -O-, -S-, - NH-, -N (CH ₃ ) -, -CO-, -COO-, -OCO-, -OCO-O-, -S- CO-, -CO-S-, -CH = CH- or -C∼C- so can be replaced that O and / or S atoms are not directly linked, and wherein also one or more H atoms by OH, NH, COOH, F, Cl, CH ₃ , OCH ₃ , CN, CF ₃ or -C~C- may be replaced, a monovalent chiral structure element G ¹ is a monovalent chromophore group T ¹ or P- (Sp-X) _n -,
R ² each independently has one of the meanings given for R ¹ , - (O) _q -CX ¹ = CX ² X ³ or, in the case of a linkage with a non-aromatic ring, also = CX ¹ X ² or
where q is 0 or 1 and X ¹ , X ² and X ³ each independently represent H or F,
P CH∼C-COO-, CH ₂ = CW-COO-, WCH = CH-O-,
CH ₂ = CH-phenyl- (O) _k -, N = C = O-, H ₂ N-, HO-, HOOC- or HS-, where WH, CH ₃ or Cl and k is 0 or 1,
Sp is a spacer group with up to 20 C atoms,
X -O-, -S-, -CO-, -COO-, -OCO-, -OCO-O-, -S-CO-,
CO-S or a single bond, and n is 0 or 1,
with the proviso that at least one of the groups Z ¹ to Z ⁵ M 'or M "as indicated in claim 1. 3. Compounds according to claim 2, selected from the group comprising Ia to Ii
in which R ¹ , R ² , Z and e have one of the meanings given in formula I,
each independently
G ² or T ² , and
L ¹ and L ² each independently of one another denote H, F, CN, Cl or unsubstituted or mono- or polysubstituted by F or Cl alkyl, alkoxy or alkanoyl having 1 to 7 C atoms. 4. Compounds according to claim 2 or 3, characterized in that R ¹ and R ² each independently represent F, Cl, CN or unsubstituted or mono- or polysubstituted by fluorine-substituted alkyl, alkoxy or alkenyl having up to 12 carbon atoms. 5. Compounds according to one of claims 2 to 4, characterized in that the bridge members different from M 'and M "Z and Z ¹ to Z ⁵ -COO-, -OCO-, -CH ₂ CH ₂ -, -OCH ₂ - , -CH ₂ O-, -C∼C- or a single bond. 6. Compounds according to one of claims 1 to 5, characterized characterized in that they have at least one polymerizable Group included. 7. Compounds according to one of claims 1 to 6, characterized characterized as having at least one chiral group contain. 8. Compounds according to one of claims 1 to 7, characterized characterized in that they have at least one chromophoric group contain. 9. A process for the preparation of compounds according to any one of claims 2 to 8, characterized in that

• a) a compound containing a propinoyl group of the formula Ia1
  R ¹ -Z ¹ - (A ¹ ) _a -Z ² - (A ² ) _b -OOC-C∼CH Ia1
  optionally reacted one or more times with propiolic acid HC∼C-COOH, the carboxyl group of propiolic acid being added to the C∼C triple bond of Ia1, and then the product of the formula Ia
  R ¹ -Z ¹ - (A ¹ ) _a -Z ² - (A ² ) _b -OOC-CH = CH) _m-1 -OOC-C∼CH Ia
  with a carboxylic acid of formula Ib
  HOOC- (A ³ ) _c -Z ⁴ - (A ⁴ ) _d -Z ⁵ -R ² Ib
  by an addition reaction as described above to give a compound of the formula I,

or

• a) a carboxylic acid of the formula Ic1
  R ¹ -Z ¹ - (A ¹ ) _a Z ² - (A ² ) _b -COOH Ic1
  optionally reacted one or more times with propiolic acid, the carboxyl group of Ic1 being added to the C∼C triple bond of propiolic acid, and then the product of the formula Ic
  R ¹ -Z ¹ - (A ¹ ) _a Z ² - (A ² ) _b - (COO-CH = CH) _m-1 -COOH Ic
  with a propinoyl derivative of the formula Id
  HC∼C-COO- (A ³ ) _c -Z ⁴ - (A ⁴ ) _d -Z ⁵ -R ² Id
  by an addition reaction as described above to give a compound of the formula I,

or

• a) a hydroxycarboxylic acid of formula 1e
  HO- (A ² ) _b -COOH Ie
  can react one or more times with propiolic acid, the product of the formula Ie1 being formed by adding the carboxyl group of Ie to the C dieC triple bond of propiolic acid, or by esterifying the hydroxyl group of Ie with the -COOH group of propiolic acid of the formula Ie2, or the product of the formula Ie3 is formed by both of the reactions mentioned above,
  HO- (A ² ) _b -COO- (CH = CH-COO) _m-1 -H Ie1
  H- (C∼C-COO) _m-1 -O- (A ² ) _b -COOH Ie2
  H- (C∼C-COO) _m-1 -O- (A ² ) _b -COO- (CH = CH-COO) _m-1 -H Ie3
  and
  • 1. in the product of the formula Ie1, the terminal acid group with a propinoyl derivative of the formula Id or Iaa
    R ¹ -Z ¹ - (A ¹ ) _a -OOC-C∼CH Iaa
    reacted as described under a) and b), and the terminal hydroxyl group with a carboxylic acid of the formula Id or Icc
    R ¹ -Z ¹ - (A ¹ ) _a - (COO-CH = CH) _b-1 -COOH Icc
    esterified, or
  • 2. in the product of the formula Ie2, the terminal acid group is reacted with a propinoyl derivative of the formula laa or Id as described under a) and b), and if appropriate the terminal propinoyl group is reacted with a carboxylic acid of the formula Ib or Icc as described under a) and b) , or optionally the terminal hydroxyl group is esterified with a carboxylic acid of the formula Icc or Id, or
  • 3. with the product of the formula Ie3, carries out the reactions described under c1) and c2),
• b) the sequence of the reaction steps described in c1) to c3) can be chosen as desired,

or

• a) a dihydroxy compound of the formula If
  HO- (A ² ) _b -OH If
  or a dicarboxylic acid of the formula Ig
  HOOC- (A ² ) _b -COOH Ig
  can be reacted one or more times with propiolic acid in the manner described under a) to c) and then reacted with a propinoyl derivative of the formula Ia or Id and / or with a carboxylic acid of the formula Ib or Icc,

wherein R ¹ , R ² , A ¹ to A ⁴ , Z ¹ to Z ⁵ and a, b, c, d and m have the meaning given in formula I, where
in the compounds of the formula Ia1, Ia, Ic1 and Ic a + b ≠ 0,
in the compounds of the formula Ib and Id c + d ≠ 0,
in the compounds of the formula Ie, Ie1, Ie2, Ie3, If and Ig b ≠ 0, and
in the compounds of the formula Iaa and Icc a ≠ 0 applies. 10. Oligomers or polymeric liquid crystalline compounds after Claim 1. 11. Use of compounds according to one of claims 1 to 10 as components of liquid crystalline media. 12. Use of compounds according to one of claims 1 to 10 for the production of liquid crystalline polymers or Polymer networks. 13. Liquid-crystalline medium with at least two liquid-crystalline ones Components, characterized in that there is at least one Contains compound according to any one of claims 1 to 10.   14. Use of liquid crystalline compounds, media and Polymers or polymer factories according to one of claims 1 to 13 in liquid crystal displays, optical and electro-optical Components, electro-optical scatter cells, optical Polarization or compensation films, orientation layers, Color filters or holographic elements, photocrosslinkable Adhesives, tensile fibers, liquid crystalline pigments, Colorants or cosmetics, diagnostic applications, as Security markings, in non-linear optics and optical Data storage or as dopants.