KR930009259B1 - Compounds for ferroelectric liquid crystal devices - Google Patents

Abstract

No content.

Description

Compound for Ferroelectric Liquid Crystal Device

The present invention relates to liquid crystal compounds and mixtures exhibiting ferroelectric properties.

In the first study of ferroelectric conversion liquid crystal displays (Reference 1: NAClark and STLagerwall, "Applied physics Letters Vol. 36 No. 11 pp 899-901 (1980.6)), DOBAMBC or HOBACPC were used as ferroelectric liquid crystals. Materials are not ideal because, in most cases, they are relatively chemically stable, light-sensitive, their spontaneous polarization coefficients are relatively small, their gradients are uncomfortably high, and they are in an uncomfortably small temperature range. Can not do it.

The present invention provides a ferroelectric liquid crystal mixture having a larger spontaneous polarization coefficient (Ps) and an improved temperature range of gradient static phase.

The relatively small values of Ps, denoted DOBAMBC and HOBACPC, are believed to at least in most cases result in relatively free rotation of these molecules of the chiral group relative to the resonance nucleus site. Molecules with identical or similar polarization groups in chiral centers have been proposed to exhibit enhanced spontaneous polarization in the absence of collision factors, when the structure of the molecule is modified to increase steric hindrance, thereby inhibiting the rotation of chiral groups. However, this is usually the case when the means capable of causing such increased steric hindrance adversely affects the formation of the liquid crystal phase, especially the liquid crystal phase having a relatively wide temperature range.

The present invention therefore relates to a ferroelectric liquid crystal mixture containing two main components which do not necessarily exhibit any spontaneous polarization action for themselves. One of these two components, which does not necessarily exhibit a gradient schizophretic on itself, and therefore does not need to exhibit any spontaneous polarization to itself, is the height of the chiral group of the molecule relative to the main nucleus of the molecule. It is a chiral substance that represents steric hindrance of The second component is provided by a material that is suitable for the first component and exhibits a gradient automatic, C, I, F, J, K, G, H or X over a wide acceptable temperature range. This second material does not necessarily contain any chiral center in its molecular structure, and therefore this material likewise does not necessarily exhibit any spontaneous polarization on itself. These two components work cooperatively in the mixture, while the second component serves to provide the essential gradient static phase of the ferroelectric smect while the first component provides the necessary chiral properties.

According to the first aspect of the present invention, there is provided a ferroelectric matic liquid crystal mixture in which the mixture is a first component is chiral and the first component is mixed with a second component exhibiting an oblique automatic phase, wherein the first component is preferred. Preferably, one having a molecular structure in which chiral groups of molecules are sterically blocked relative to their main nucleus such that the polarization of the molecules of the first component in the mixture produces a spontaneous polarization with a maximum exceeding 10 nC cm ^-2 . Or more compounds. These mixtures will hereinafter be referred to as "bicomponent ferroelectric mixtures as defined above".

The maximum value of Ps in this mixture is ideally at least ²⁰ nC cm ⁻² , and may also be larger than the above value, especially in an inclined liquid crystal phase arranged more than in the liquid crystal C (Sc) phase.

In the absence of an effective steric hindrance, the chiral group cannot rotate completely freely when the first component is mixed with the liquid crystal second component, so the transverse spectral component combined with the chiral center virtually imparts spontaneous spectroscopy to the mixture. However, in the presence of significant steric hindrance, which tends to block rotation of chiral groups into the molecular nucleus, natural spectral values have been found to increase significantly. From these observations, in the presence of significant steric hindrance, transverse spectroscopy combined with polar substituents at molecular positions other than chiral groups should contribute to obtaining high natural spectroscopic values. In the present specification, it is generally easier to incorporate high polar substituents at positions other than chiral groups, and in many cases, one or more such substituents can be provided and the substituents can be positioned so that their effect is further enhanced. It is important to note.

One of the particular advantages of using two different components of the ferrous liquid crystal mixture is that it alleviates the problem of obtaining materials that exhibit high Ps values over a relatively wide range of temperatures. The molecular form of the first component is primarily intended for the purpose of providing large transverse spectroscopy, despite large transverse spectroscopy, which is likely to act over a wide range of temperatures in gradient liquid crystals (these phases are evenly present in the material). Can be. Likewise, the second component, host material, may be formulated at a wide range of temperatures in the gradient liquid phase to provide a mixture to cover the required temperature range.

In obtaining a relatively high Ps value caused by the lowering of the free rotation of the carral center with respect to the main nucleus of the molecule, it is not necessary to provide a chiral center with a strong dipole moment if the rotation is greatly reduced. Dipoles can advantageously be incorporated into the nucleus of the molecule. This has several advantages, including ease of synthesis, the availability of one or more polar groups, and generally higher chemical stability. With respect to the factors mentioned later, it should be noted, for example, that alkylchlorides are generally less chemically stable than arylchlorolides.

One particular method of reducing the free rotation of chiral groups is to position the chiral center as closely as possible to the main nucleus of the molecule, for example by directly binding to the carboxyl group of the aromatic acid portion of the ester.

Another way to reduce the free rotation of chiral groups relative to the main core of the molecule is by steric hindrance between the chiral groups and the main core. This can be achieved by containing bulky or polar substituent groups on the main molecular core and / or chiral groups that interfere with free rotation.

The steric phenomena are well known in other chemistries, and the synthesis of molecules having chiral centers whose free rotation with respect to the molecular core is steric hindrance is relatively well known to the relevant chemist, and the method can be known from the literature.

Many other compounds that can be used as primary components of a two-component mixture as defined above involve several disadvantages. These shortcomings include the lighting of the price and the difficulty of obtaining optical purity during synthesis. Synthesis can start from optically pure (+) or (-) enantiomers, but some racemization may occur during synthesis. Such racemization products are less efficient and often completely inefficient in the preparation of chiral smectic phases. Degradation of racemization products is often very difficult.

Thus, according to a second aspect of the present invention, the bicomponent ferroelectric mixture as described above contains at least one naturally occurring derivative in its primary component. The term 'naturally occurring' means available from the plant resources.

In a second aspect of the present invention, a group of a plurality of naturally occurring molecules contains chiral centers at individual carbon atoms or groups within the molecule, and chemically combines with other groups to form a hindered molecule with respect to the main molecular core. You can take advantage of the fact that you can.

In addition to the advantages provided by the chemical structure of many naturally occurring chiral compounds (ie, using the steric hindrance described above), other advantages of natural compounds are low cost and can be used in large quantities from animal or plant resources (eg waste). Is that there is.

Another great advantage is their optical purity. Biosynthetic reactions often exhibit extreme stereospecificity, and naturally occurring chiral molecules are often formed only in the form of D (dextro) or L (laevo) in flora and fauna. In addition, naturally occurring chiral compounds contain functional groups, such as hydroxy, amino or carboxylate groups, which can be readily combined with other groups in stereospecific synthesis to form molecular cores.

Naturally occurring chiral compounds are widely present and can be used in the present invention. It is advantageous to use compounds containing suitable functional groups at suitable sites in the molecule.

It is preferred to use a naturally occurring chiral molecule having a bulky group adjacent to the functional group used to bind to the main molecule core to enhance steric hindrance at the chiral center for the main molecule core.

In the present invention, it is particularly preferable to use derivatives of naturally occurring compounds of the following classes:

(i) hydroxy carboxylic acid; These may be α- or β- isomers containing chiral centers. α-hydroxy carboxylic acids are usually preferred, and they contain chiral units such as the following general formula (9):

Wherein a may be 0 or 1

R is alkyl, alkoxy or

Wherein n can be 0 to 3 and X represents alkyl, alkoxy, halogen substituted alkyl or alkoxy, alkylcarbonyloxy, alkoxycarbonyl, CN or halogen.

[예를 들면, 일반식(9)의 R이 페닐인 것]이 바람직하며, 특히 전자의 락트산 유도체는 상기한 바와 같은 2-성분 강유전성 혼합물중에서 특히 유용한 계열의 화합물임이 밝혀졌다.Among the hydroxy acids, lactic acid, ie CH ₃ ^* CH (OH) CO ₂ H [for example, R in general formula (9) is methyl] and mandelic acid, ie

[For example, R in general formula (9) is phenyl], and the former lactic acid derivative has been found to be a particularly useful class of compounds in the two-component ferroelectric mixture as described above.

Since there are two directly adjacent functional groups, -OH and -CO ₂ H, next to the chiral center in the α-hydroxy carboxylic acid, the chiral center is directly linked to the molecular nucleus of the compound of formula (6) by ester bonds The compound of formula (10) can be prepared.

(Here, derivatives such as esters can be prepared)

In the compound of formula (10), the chiral center is stericly disturbed due to its proximity to the molecular nucleus.

-하이드록시-이소부티르산(12)이다.Examples of chiral β-hydroxy carboxylic acids are β-hydroxy-n-butyric acid (11) and

-Hydroxy-isobutyric acid (12).

If the binding of the chiral center to the molecular nucleus takes place via a carboxylate unit in (11) and in the hydroxyl unit in (12), the chiral center is more than the main molecular nucleus, where there is an interfering CH ₂ group. Therefore, it will be less disturbed in three dimensions. That is, the β-hydroxy carboxylic acid is considered less effective since the first substituent in the mixture of the present invention produces high Ps.

[Gamma]-, [delta]-derivatives and other isomers of hydroxy carboxylic acids can also be used, but they are less suitable since they tend to produce cyclic lactones.

Derivatives of hydroxy carboxylic acids are esters (i.e., a = 1) or amides (i.e., by carboxylate group ester linkages of the nucleus through their OH groups or from their OH or amine groups to their carboxylate groups. = 0) can be easily bonded to the main molecular nucleus by a bond. Such binding reactions are derived from known literature methods and also pending patent applications of the applicant [UK Patent Application No. 84 28 653. ref: D / PD Pats (PO102), "Alpha-Hydroxycarboxylic Acid Derivaives suitable for use in Liquid Crystal Materials and Devices"].

(ii) amino acids; There are chiral α-, β-, γ- or δ-amino acid derivatives, but the easiest is the known family of saturated α-amino acids that can form and bulk most of the animal protein. α-amino acids have chiral centers.

Wherein A is a residue of an α-amino acid.

For example, in the case of α-alanine, A is methyl in the CH ₃ -CH (NH ₂ ) CO ₂ H structure. Natural α-amino acids are listed in Table 1 showing each residue A.

α-amino acids are usually bound to the main molecular nucleus by their aminofunctional groups or their carboxylate groups. Amino groups can be easily bound by amino-type bonds, and carboxylate groups can be readily produced in the molecular nucleus by means of ester or amide bonds, in chiral units in the molecule of the following structural formula.

TABLE 1

Natural α-amino acids

In this type of molecule, N-H units are less soluble in liquid crystalline materials because they tend to form polar or more ionic structures. Accordingly, it is preferable to substitute the number NH unit by the NB unit, wherein B is a group containing no hydrogen, which is likely to form strong hydrogen bonds, for example, alkyl, preferably n-alkyl having 1 to 20 carbon atoms, Methyl or acyl, i.e., -COR, wherein R is alkyl, preferably n-alkyl having 1 to 20 carbon atoms, especially ethyl.

Some residues A of natural α-amino acids also contain functional groups, for example aspartic acid (15) containing a carboxylic acid group at the residue, ornithine (16) containing an amino group at the residue and a hydroxy group at the residue. It is a serine (17) containing these.

Others will be apparent from Table 1.

The functional groups in these residues may also cause undesirable polarity, in the structure of (14) converting the NH ₂ units of the amano groups in the residues to NBB ′ units, the carboxylate groups in the residues being ester or amide groups, That is, it is preferable to convert the COOB group or the CONBB 'group, where B' may be selected from the group in which B is selected, and convert the OH group in the residue to OB units, where B is particularly acyl.

In addition to binding the α-amino acid group to the molecule by the method shown in (14), the α-amino acid group is used when NH, CO ₂ H and OH functional positions are present in residue A, and CO ₂ H and It is also possible to bind to the molecule via an ester bond in the case of an OH action site and through an amide bond in the case of a CO ₂ H and NH action site. The binding at this position in the residue may be in addition to or in place of the use of NH and CO ₂ H groups at the α-position, where the chiral units of the above kind are bound to the main atomization nucleus at any of the positions mentioned above. Enable structure

Wherein B and B 'may be the same and R is alkyl, preferably n-alkyl having 1 to 20 carbon atoms, in particular ethyl.

In the above structural formulas (14), (18) and (19), the chiral center in the amino acid unit is stericly impaired compared to the main nucleus of the molecule, and the main nucleus of the molecule is bound to nitrogen via an amide bond, that is, -CON-. In the case of containing an aromatic group, there is a possibility of ring-?-Amide interaction which closes the desired coordination of the amide to the ring.

Appropriate chemical synthetic routes of this kind of compounds can be derived from the literature, essentially using standard esterification and amidation reactions. Careful protection and deprotection steps are required if two or more identical functional groups are present in the molecule. How to do this is described in Applicants' pending patent applications UKPA 8520714 and 8524879.

(iii) terpenoids; It is a series of natural compounds derived from isoprene: monterpenoids (two isoprene units), sesquiterpenoids (three isoprene units), diterpenoids (four isoprene units) and triterpenoids ( Six isoprene units). Terpenoids may be monocyclic, bicyclic or tricyclic. Not all terpenoids are chiral, of which monoterpenoids, acyclic monoterpenoids and tricyclic sesquiterpenoids are preferred.

Examples of chiral monocyclic monoterpenoids include menthol (20) neomentyl, isomenthol, neoisomenthol, carveol, dihydrocarbenol, terpin-4-ol, α-terpineol and limonene-10- It's coming

Examples of chiral bicyclic monoterpenoids include bornolol 21 and isobornaneol.

Examples of chiral tricyclic sesquiterpenoids include long Zipolol 22 and cedrol.

The main functional group in the terpenoid structure is hydroxyl, so it is relatively simple to form ester bonds linked to the main molecular center.

It is preferred that terpenoids containing hydroxyl functional groups having a bulky group at adjacent position (s) be used to promote steric hindrance of chiral units associated with the main molecular center. For example, bulky isopropyl side chains in methanol at adjacent ring positions relative to the hydroxyl hinder rotation about one bond to the hydroxyl.

However, in the case of terpenoids, it has been found to have two inconsistent effects: when terpenoid derivatives are used as the first component in the mixture of the present invention, the presence of large side groups promotes high Ps, The group promotes the appearance of the smectic phase. As a result, it was found that the derivative of methanol promotes high Ps but does not provide a smetic phase. The isofinocamphorol derivative (23) eventually appears to be the best.

Methods of preparing derivatives of chiral terpenoids by esterification are known to those skilled in the art and are described in pending British Patent Application No. 8501999.

(iv) steroids; These are a large class of organic compounds based on the perhydro-1, -2 cyclopenteno-phenanthrene ring system (24).

위치에 히드록실-치환된다. 다른 위치에 치환체를 갖는 스테롤은 드물며, 대량으로 사용하기 위한 그것들의 분리가 비용이 많이 들므로, 그것들의 유리한 점을 감소시킨다.Derivatives of cholexterol have a nematic liquid crystal phase and are called chiral nematic “cholesteric” mesophases, but their use in smectic liquid crystals is new. Naturally occurring sterols are almost all at position 3, ring A

Hydroxyl-substituted at the position. Sterols having substituents at other positions are rare, and their separation for use in large quantities is expensive, thus reducing their advantages.

(v) other naturally occurring chiral molecules; Many of the naturally-occurring chiral molecules can be classified into groups of the above-mentioned molecules, e.g., functional groups that are subject to stereospecific reactions, adjacent to functional groups that promote steric hindrance but are not expected to suppress smectic morphogenesis. Adjacent bulky side chains, cheap expense, non-polarity, have desirable properties consistent with the materials. Possible methods of preparing the derivatives have at least some of these properties, but may include the following disadvantages until proper substitution is made.

Sugar-crude, optically pure functional -OH group, excessive hydrophilicity and excessive polarity.

Polycarboxylic acids, glyceraldehyde derivatives.

The molecular centers where the aforementioned chiral units are linked to form a compound suitable for use as the first component of a bicomponent ferroelectric mixture as defined herein can generally be indirectly or directly connected by crosslinking groups, As is well known in the liquid crystal art and as exemplified in structures (1) to (7) it will consist of chains of cyclic groups which sometimes have alkyl or alkoxy terminal substituents.

When the chiral unit has two binding positions as in the α-hydroxycarboxylic acid group (9) or amino acid unit (14), (18) and (19), the structure of the derivative is as follows.

X- (C ^* ) -Y

Wherein C ^* is a chiral unit; X is a group of the following structure; R ₁ -S ^9- (A ¹ S ¹ ) _i- (A ² S ² ) _j- (A ³ S ³ ) _k- (A ⁸ S ⁸ ) _r- ; Y is a group of the following structure; -(S ⁷ A ⁷ ) _p- (S ⁶ A ⁶ ) _m- (S ⁵ A ⁵ ) _m- (S ⁴ A ⁴ ) ₁ -S ¹⁰ -R ₂ ; R ₁ and R ₂ are each independently hydrogen, alkyl, alkoxy, fluoroalkyl fluoroalkoxy, alkoxy substituted alkyl, alkanoyl, alkanoyloxy, alkylcarbonyloxy, alkoxycarbonyl or halogen; S ¹ , S ² , S ³ , S ⁴ , S ⁵ , S ⁶ , S ⁹ and S ¹⁰ are independently a single covalent bond, or CO (0) _a , (0) _a OC, CH ₂ , CH ₂ CH ₂ , CH ₂ O, OCH ₂ , -CH = N-, N = CH, CHD, CH ₂ CHD and CHD-CH ₂ , wherein D is CN, CF ₃ , CH ₃ or a halogen substituent ; R ⁷ and R ⁸ are each independently a single covalent bond or one of the groups selected from S ¹ , S ² , S ⁴ , S ⁵ , S ⁶ , S ⁹ , S ³ or S ¹⁰ , and S ⁷ is May also be (CH ₂ ) _q , wherein q is 1 to 12; A ¹ to A ⁸ are phenyl, cyclohexyl, bicyclo (2, 2, 2) octyl, pinane, naphthyl, pyridyl, pyrimidyl, piperidyl, or one or two -CH ₂ -units are each oxygen Or a cyclic group selected from cyclohexyl substituted with sulfur, which group may be substituted with one or more substituents; a, i, j, k, l, m, n, p and r are each independently 0 or 1.

When the cyclic group A ¹ , A ² , A ³ , A ⁴ , A ⁵ , A ⁶ is bonded to a chiral unit (C ^* ) by one of S ¹ to S ¹⁰ , the combination of the cyclic group and the chiral unit It is preferable that it is a silver amide or ester bond.

When the chiral unit has only one binding site, as in the case of terpenoids, the structure of the derivative is as follows.

X-T

Wherein X is as defined above; S ⁷ is preferably an ester bond.

If the derivative is a testenoid, group X becomes the molecular nucleus. When the derivative is a hydroxycarboxylic acid or amino acid, X or Y may be a molecular nucleus. If the sizes of X and Y are approximately the same and / or both contribute to the liquid crystalline properties of the mixture, then it is easy to think of them as the molecular nuclei where X and Y are combined, in which case the chiral unit is X and / or Y, or Both of them can be steric hindrance in relation to.

Preferred structure of X is as follows:

In the above formula, b is 0 when an amide bond is formed together with a chiral unit, and b is 1 when an ester bond is formed; The phenyl ring may be substituted; R is particularly preferably m-alkyl or m-alkoxy having 5 to 12 carbon atoms.

Preferred structure of Y is as follows:

Wherein (F) and (CH ₃ ) indicate that one or more of the specified substituents may be present, m may be 0, 1 or 2.

For derivatives of α-hydroxy carboxylic acids and amino acids a preferred combination of X and Y is that X is one of (24), (25) or (26) and R is n-octyloxy and n-alkyl, in particular R ₂ Ethyl.

Other preferred X and Y combinations of lactic acid and amino acid derivatives are described in the Applicants copending patent application Ref D / pD Pats / PO 102 and 8520714 and 8524879.

The first of these properties is the use of a first construct having a molecular structure in which the chiral group of molecules is sterically disturbed relative to the main molecular core in the two construct ferroelectric mixtures described above and a derivative of the naturally occurring chiral molecule. The use of the construct is generally applicable to the smectic second construct. The advantages provided by the present invention are usually independent of the nature of the second construct.

While it is obvious that the first construct does not need to exhibit a tilted smetic phase, it is in fact beneficial when presenting such a phase. In addition, the main core of the first construct is compatible with the molecular molecular lattice, so tumbling or excessive movement with respect to the host should be prevented. It should also be appreciated that high solubility is a desirable property for the first construct, as long as there is a large distribution of this construct in the mixture and a large value for spontaneous polarization. Generally, the second constituent, the material exhibiting the tilted smectic phase, will typically be a process mixture of several compounds but not a single compound. Similarly, the first construct may be a single compound, but in many circumstances it may be an advantage to use different mixtures and also the same kind of mixture of natural compounds (eg two lactates) or different kinds (eg lactate and tere) Penoids).

Many suitable second constructs (or “hosts”) are known as commercial material racemate CE 8.

It has the following structural formula.

Examples of suitable smectic hosts are as follows.

(a) the compounds and compositions described in European Patent Application No. 0110299 A 2

(b) compounds and compositions described in Mol. Cryst. Liq. Cryst (37) 157 (1976), for example esters having a central core of the following structure:

(c) Known compound of the following structure

(Or mixtures thereof which may be racemic mixtures) (wherein R _C and R _D independently represent n-alkyl or n-alkoxy and one of them is a chiral group. For example, if R _C is nC ₈ H ₁₇ and R _D is (+)-2 methylbutyl, these compounds may be purchased from BDH Chemicals Ltd, Broom Road, Poole, Dorset UK, etc.]

(d) compounds and compositions described in British Patent Application No. 8501509, for example compounds of the structure:

(e) Known compounds of the following structure or mixtures thereof:

_Wherein one of R _A and R _B is C _5-12 n-alkoxy and the other is C _7-12 n-alkyl or n-alkoxy. These compounds are non-chiral.]

(f) Known Compound PG 495:

(g) the following known compounds or mixtures thereof:

(F) and (g) are both BDH Chemicals Ltd. Marketed by.

Other suitable smetic host materials that can be mixed with the compound of formula (I) are apparent to those skilled in the art.

The mixture containing at least one compound of the present invention and exhibiting a chiral static phase is characterized by other properties required by the individual devices, such as viscosity, dielectric isotropy, birefringence, pitch, elastic constant, melting point, bright point, and the like. One or more additives for imparting can be added. Preference is given to additives which exhibit a weak longitudinal dipole moment (eg compounds containing alkyl and / or alkoxy end groups). Preferably these materials exhibit positional dipole moments, for example by containing positional halogen, CF ₂ or CN substituents.

In the field of smectic and liquid crystal chemistry, the structural requirements for miscibility are not well known and therefore there are some difficulties in predicting which compounds will form stable mixtures with smectic phases. Therefore, it may be necessary to perform some relative direct experiments to determine if a particular combination of compounds such as the host or additive described above forms a stable mixture. This experiment would in most cases dissolve a combination of one or more compounds together (if they are not liquid at room temperature) and observe the appearance of the smetics using known methods such as an optical microscope.

Most studies of data in this relatively new field have focused on the discovery of good working combinations of hosts and dope agents, and further work will be directed towards improving the combination with additives.

There is some evidence that compounds having a combination of cyclic and binding groups in the same or extremely close molecular core or structure thereof, for example, compound PG 495 is a lactate-ethyl ester substituted 2-methyl Miscible with its fluid having a butyl ester group. The fact that this theory is not absolutely conclusive is demonstrated by the broad range of compounds that are miscible with PG 495 and RCE 8 in Tables 7-12.

Some examples of available additives are listed in Tables 4, 5, and 6 below, but these are only general guidelines and should be tested in each case to investigate suitability.

Examples of compounds that can be added to the compounds of the present invention and one or more smectic compounds or mixtures containing the materials of (a) to (e) above to produce room temperature Smematic C phases are listed in Table 4 below.

TABLE 4

Wherein R and R 'are alkyl or alcoholic, and R _A is alkyl.

Preferably, R is C _5-12 n-alkyl or C _5-12 branched alkyl or alkoxy containing asymmetrically substituted carbon atoms such as 2-methylbutyl.

Examples of low-melting and / or low-viscosity additives are the compounds shown in Table 5 below.

TABLE 5

Wherein R is each independently alkyl or alkoxy such as C _1-18 n-alkyl or n-alkoxy, and R _A is each independently alkyl such as C _1-18 n-alkyl.

Examples of high-brightness additives are the compounds listed in Table 6 below.

TABLE 6

Wherein R is alkyl or alkoxy such as C _1-12 alkyl or alkoxy and R _A is alkyl such as C _1-12 or a fluorinated analog of these compounds.

Examples of mixtures of the present invention are as follows:

(i) a component consisting of at least one of the aforementioned compounds (a) to (g). 25 to 75 mol%

(ii) a component consisting of one or more of the compounds listed in Table 4 above. 0-30 mol%

(iii) a component consisting of one or more of the compounds listed in Table 5 above. 0-30 mol%

(iv) a component consisting of one or more of the compounds listed in Table 6 above; 0-30 mol%

The amount of each compound to make 100% by mixing with at least one compound of the present invention contained in the mixture of the present invention varies depending on the properties required in the mixture, including the pitch and Ps of the molecular coordination on the chiral smectic. . When causing increased Ps in a host of a compound of the invention, the induced Ps value is generally increased by the amount of compound present in the host.

Alternatively or additionally, some of the compounds of the invention may act as hosts, in which case they may be optically active or racemic to which a suitable dope may be added (which may be compounds of different general formula (I)), Other ingredients, such as those illustrated in Tables 4, 5 and 6, can be added to the mixture.

When a mixture is prepared by mixing the first component of one or more compounds of the invention with the second component, which may contain a compound of the invention and may be chiral, each molecular twist concept thereof or each caused by the two components Molecular twist concepts can be the same or opposite. If the two concepts mentioned are contradictory, the resulting mixture exhibits a spiral pitch longer than the two components (if separate chiral smectic). The concept of twist is equivalent to a shorter pitch component, ie a more powerful twist, for the same mixture of two chiral smectic components. By this principle, the pitch of the mixture can be adjusted to suit its intended use. The method allows producing a mixture with an effectively infinite pitch in which the individual twist concepts of the components cancel each other out.

In some mixtures, the concept of polarization (see also FIG. 1), i.e. (+) or (-), may be the same or opposite.

Therefore, it is possible to produce a mixture with a positive polarization while having a twisted concept of the components and offsetting each other.

Liquid crystal mixtures that exhibit an S ^* ferroelectric liquid crystal phase and contain one or more compounds of the invention as a dope or host or both, and at the same time also contain one or more other compounds described above, constitute another aspect of the invention.

Liquid crystal ferroelectric materials containing the compounds of the present invention can be used in known liquid crystal electro-optical devices such as processing, storage and display devices utilizing the properties of the S ^* mesophase.

An example of such a device is the "Clark Lagerwall Device" described in Reference 1 above and in the following reference (Ref. 3: "Recent Developments in Condensed Matter Physics", 4, p 309, (1981)). Features and methods of manufacturing such devices are known. In practice, such devices generally consist of two substrates (at least one of which is optically transparent), an electrode on the substrate inner surface, and a layer of liquid crystal material sandwiched between the substrates.

When such a device contains the compound of general formula (I), this also falls within the scope of the present invention.

The Clark Lagerwall device uses a layer of liquid crystal material between substrates of thickness less than or comparable to the helical pitch of the S ^* configuration, which prevents winding by surface interactions called helix. In the unwinded state, the liquid crystal material has two surface stabilization states, which have an indicator orientation (i.e., a molecular tilt direction) of twice the angle of inclination with each other and also a permanent dipole orientation perpendicular to the substrate but in the opposite direction.

Another method of providing a cell in a Clark Lagerwall device with a thick layer of liquid crystal material is to use homogeneous electrical applications to induce homogenization agreement through the interaction and dielectric anisotropy of the liquid crystal material. This effect requires a chiral smectic material with negative dielectric anisotropy, which can be provided by the inclusion of compounds with positioning halogen or cyano substituents.

In general, chiral smear C materials (Sc ^* ) are used in these indicators because most of them are fluids, but theoretically better chiral smectes may be used. A polychromatic dye may be added to the liquid crystal material to enhance the electrooptic effect.

Such devices containing compounds of general formula (I) offer the potential for high conversion rates of millions of seconds and bistable storage capacity, as shown in Ref. 3, and thus, for indicators, optical processors and optical storage devices. It can have important uses. In particular, this makes it possible to manufacture electro-optical devices in the form of large screens, eg 30 cm × 20 cm, suitable for use in visible indicator units, portable computers and the like.

Examples of the preparation and properties of the compounds embodying the present invention will be described herein later. Abbreviations and symbols used in the following examples have the following meanings:

h = hour;

g = gram;

mp = melting point;

bp = boiling point;

hplc = high pressure liquid chromatography;

CS _A , _B , _C ... = Crystalline solids vs. Smetics A, B, C... Liquid crystal transition temperature ℃;

=나트륨-D 라인을 사용하는 24℃에서의 광 회전각 ;

= Optical rotation angle at 24 ° C. using sodium-D line;

Hosts: RCE8 Racemic

RPG 495 is a race

Ps (nC cm ^-2 ) = spontaneous polarization

use the amplitude of the effective dipole moment, μeff = (Ps MW) / (NA ρ), which contributes to μeff (D) = Ps;

MW = molecular weight

NA = Avogadro's number

ρ = density (1000kgm ^-3 )

Ps and μeff are extrapolated to a 100 mol% concentration from a mixture having a concentration of about 10 mol%.

All data on the concept of Ps, μeff, tilt angle, and polarization are provided at temperatures 10 ° C. lower than the S _A -S _C ^* transition temperature unless otherwise indicated.

The dope agent concept of polarization is limited to the first degree.

Preparation of the following general formula compound using reaction route (b)

Step 1a: Preparation of (S) -propyl Lactate

(S)-(+)-lactic acid (53.0 g, 0.59 mol) and propanol (75.0 g, 1.25 mol) were added to a stirred suspension in sodium-lite benzene (300 cm 3) of Amberlite IR-120 (H) (20.0 g). Added. The water was then collected in a Dean and Stark apparatus while heating the stirred reaction mixture at reflux for 5 hours. After cooling, the resin was filtered off and washed with that fraction (25 cm 3) of benzene. The benzene filtrate was then shaken with potassium carbonate (5.0 g), filtered and washed with a small amount of benzene.

Distillation under reduced pressure (water-pump) gave 31.5 g (44%) of (S) -propyl lactate as a colorless liquid (bp = 69 ° to 73 ° C.), nmr analysis showed (S) -propyl lock. Tate was still contaminated with propanol. This was removed by air distillation using toluene.

The product was then distilled off again under reduced pressure (water-pump) to give 23.0 g (32%) of (S) -propyl lactate as a colorless liquid (bp = 69 ° to 71 ° C.). The product did not contain propanol.

Step 1b: Preparation of (S) -propyl 2- (4'-octyloxybiphenyl-4-carbonyloxy) propanoate

4'-n-octyloxybiphenyl-4-carboxylic acid (5.9 g, 0.0153 mole) was heated mildly under reflux for 3 hours with excess freshly distilled thionyl chloride (30 cm 3). Unreacted thionyl chloride was distilled off under reduced pressure, and the crude acid chloride was dissolved in anhydrous dichloromethane (10 cm 3). A solution of the acid chloride was then added dropwise to a stirred solution of (S) -propyllactate (prepared in 2.25 g-step 1a) and anhydrous dichloromethane (10 cm 3) of anhydrous triethylamine (2 cm 3). The reaction mixture was then stirred at rt for 16 h.

The cold reaction mixture is diluted with anhydrous dichloromethane (20 cm 3), washed with dilute hydrochloric acid and water and finally dried over magnesium sulfate.

The crude ester was purified by column chromatography on silica gel using chloroform as eluent. Recrystallization several times with ethanol yielded 2.5 g (37%) of (S) -propyl 2- (4'-octyloxybiphenol-4-carbonyloxy) propionate as a crystalline solid (mp = 58 ° C). ).

The purity of the product was examined by hplc (anti-subject: various water / methanol mixtures). The chemical structure of the product was confirmed by the combination of the following methods;

^1.1 Hnmr spectroscopy (using Jeol J NM-PM × 60 model spectrometer)

2. Infrared spectroscopy (using Perkin-Elmer 4571 model spectrophotometer)

3. Mass spectrometry (using AEI MS 902 model mass spectrometer)

Optical purity of the product was determined by nmr spectroscopy using chemical transfer reagents.

Example 2

(S) -ethyl 2- (4'-octyloxybiphenyl-4-carbonyloxy) propanoate was prepared by a similar procedure as in Example 1. The product was measured in terms of its composition and purity as in Example 1 (CS _A = 39 ° C, S _A -I = 42.0 ° C).

(S) -Ethyl lactate used in Example 2 was prepared from Aldrich chemical Co. Ltd. (Dorset, Gilingham, UK).

Example 3

(S) -Methyl 2- (4'-octyloxybiphenyl-4-carbonyloxy) propanoate was prepared by a procedure similar to Example 1. The composition and purity of the product were measured in the same manner as in Example 1. The product showed CI = 57 ° C. and S _A -I = 49.2 ° C. (monotropic).

(S) -methyl lactate used in Example 3 was prepared from Aldrich Chemical Co. Ltd. It was marketed by.

Example 4

(S) -n-butyl 2- (4'-octyloxybiphenyl-4-carbonyloxy) propanoate was prepared by a procedure similar to Example 1. The product was measured in the same manner as in Example 1 regarding its composition and purity (mp = 51 ° C.).

(S) -n-butyl lactate used in Example 4 was prepared in a similar manner as in step 1a. It was confirmed that this compound has a melting point (water pump) of 86 to 89 ° C.

Example 5

Preparation of Structural Compounds

4-n-octyloxybiphenylyl-4'-carbolic acid (10 mmol) is stirred in anhydrous benzene with oxalyl chloride (29 mmol) and dimethyl formamide (catalytic amount) for 2-3 hours. The solvent and unreacted oxalyl chloride are then removed by vacuum evaporation.

Results 4-n-octyloxybiphenyl-4'-carbonyl chloride was dissolved in anhydrous dichloromethane (30 ml) and dissolved in 1-alanine (10 mmol) solution in severely stirred saturated sodium hydrogencarbonate aqueous solution (100 ml) for 20 minutes. Add it down. After stirring is continued for another 30 minutes, the solution is acidified and the organics are extracted with dichloromethane (3 x 50 ml).

The crude amine obtained by drying and evaporating the combined extracts was purified by flash chromatography on silica gel using ethyl acetate: petroleum fraction (boiling point 60 ° to 80 ° C.) 3: 1 as eluent, and the compound of formula Obtained in 60-70% yield.

N- (4'-n-octyloxybiphenyl-4-oyl) -L-aladdin (10 mmol), N, N'-dicyclonucleosilcarbodiimide (11 mmol), 4-n-butoxyphenol (11 mmol) , 4-pyrrolidinopyridine (1 mmol) and dichloromethane (50 ml) are stirred at room temperature until the end of the reaction (tlc). Precipitated N, N'-dicyclohexylurea is filtered and the filtrate is washed continuously with water (3 x 50 ml), 5% acetic acid aqueous solution (3 x 50 ml) and again with water (3 x 50 ml).

The crude ester obtained by drying and evaporating the organic layer is purified by flash chromatography on silica gel using ethyl acetate: petroleum fraction (boiling point 60-80 ° C.) 3: 1 as eluent (see A Hassner and V Aleanian Tetrahedron Letters 1978). , 4475].

The following structural compound is obtained in 86% yield at a melting point of 184 to 185 ° C.

Similar processes produce two compounds of the structure

These P _S values are determined by extrapolation from the value in 10% solution of each racemate of the following structural compound.

The P _S values measured by extrapolation were 141 and 138, respectively.

Example 6

Preparation of (-) Methyl 4-n-decyloxybiphenyl-4'-carboxylate

4-n-decyloxybiphenyl-4'-carboxylic acid (2 g; 0.0056 m) prepared by hydrolysis of 4-cyano-4'-n-decyloxybiphenyl (BDH, Poole, Dorset) was added to 3 Heat with thionyl chloride (30 ml) for time. Thionyl chloride was removed on a rotary evaporator; The remaining thionyl chloride is evaporated off by air distillation using anhydrous benzene.

Acid chloride is dissolved in anhydrous pyridone (30 ml) and cooled in an ice bath. (-) Menthol (0.94 g; 0.006 m) [[D] ¹⁶ _D = -44 °] is dissolved in a minimum volume of anhydrous pyridine and added to the acid chloride solution over 15 minutes. The reagents are stirred in an ice bath for 1 hour, then at room temperature overnight, and finally at 60 ° C. for 2 hours. After cooling, the mixture is poured into brine hydrochloric acid (100 ml) and the product is extracted with dichloromethane (100 ml). The dichloromethane layer is washed five times with a dichloric acid solution (100 ml), then with water (100 ml) and finally with a sodium bicarbonate solution (100 ml). The dichloromethane solution is dried over magnesium sulfate and then rotary evaporated to leave only low melting solids. This is purified by column chromatography on silica gel (70 to 130 mesh) using 1 part dichloromethane 1 part petroleum ether (boiling point 40 to 60 ° C.) as eluent. The separated solid is crystallized from IMS by thin layer chromatography to a constant melting point and single spot purity. The melting point of the final product is 26 ° C., and the stroke that it is a true ester is provided by the presence of an infrared absorption peak at 1710 cm ⁻¹ corresponding to the C = 0 stretching frequency.

Example 7

The above method is repeated using 4-n-octyloxybiphenyl-4'-carboxylic acid and (-) menthol. The melting point of the product is 57 to 58 ° C. By measuring 3-14 weight percent solution of this product in racemic CE 8 extrapolation P _S for the material of 52 and 71.6 nCm ^-2 to temperatures of 5 and 10 ° C. below the S _A -S _C ^* transition, respectively (Compare this with the extrapolation P _S of the corresponding 53 and 78 nCm ⁻² cited above for the decyloxy analog of Example 1).

Referring now to the accompanying drawings, a tightly sealed cover against the liquid crystal layer is formed safely with two glass sheets 11 and 12 and a peripheral seal 13. The interior facing the surfaces of the two sheets has transparent electrode layers 14 and 15 of indium tin oxide, each of which has a polymer layer (e.g. polyimide) provided for molecular alignment purposes within the display area defined by the peripheral seal. , 17). Since the two polyimide layers are rubbed in one direction, when the liquid crystal contacts them they will promote the planar alignment of the liquid crystal molecules in the rubbing direction. The cells are collected in a rubbing direction aligned parallel to each other. The thickness of the liquid crystal layer contained in the resulting covering is measured by the thickness of the peripheral seal, and control of its accuracy allows light scattering of short lengths of uniform diameter glass fibers (not shown) distributed through the surrounding seal material. Can be provided by

After sealing, a vacuum is applied to an opening (not shown) through one of the glass sheets at one corner of the surrounding area so that the liquid crystal medium enters the cell through another opening diagonally opposite the corner (not shown). It is convenient to charge (seal the cranial opening after the filling process). The filling process is carried out using a filling material heated to an isotropic phase to reduce the viscosity to an appropriately low value. The base structure of the cell is, of course, similar to the base structure of a conventional twisted nematic except for the parallel friction direction.

Typically the thickness of the perimeter of the seal 13 and thus the liquid crystal layer 18 is about 10 microns, but for example, whether the process needs double stability and whether the layer is manipulated or more orderly on the S _C ^* phase. Depending on the operation with the phase (eg S ₁ ^* or S _F ^* ), thicker or thinner layers may be necessary to suit the particular application.

The liquid crystal layer is a two-component ferroelectric mixture as described above. The first component may be, for example, one of the materials specifically described in the examples or a mixture of such materials. In the above description, certain two-component mixtures use racemic CE8 as the second (host) component. Although CE8 is a suitable material to specifically characterize the properties of the first component material, CE8 is a practical display device because the temperature range of the filtered smearable phase is relatively narrow and this temperature range is importantly above room temperature. In particular, it is not very suitable. Therefore, as the second component of the non-experimental apparatus, it is generally preferable to use a mixture as follows without using CE8 as the only second component.

Such cells can be used, for example, in displays, optical switch devices and optical information processing devices.

In use, the cell is generally installed between one polarizer 19 having an axis that is flat in the friction direction and another polarizer having an axis perpendicular to the friction direction to dim the light so that the cell is transparent, ie bright and opaque, i.e. dark Will have status.

The present invention is illustrated in Table 2 below by comparison of various compounds with P _S in the nCm- ² values. Lactates, amino acids and teptenoid derivatives are prepared using the methods described in the corresponding pending African patent applications.

Cited P_SValue is extrapolated P_SIe P in the Smematic C phase of the particles (racemic CE 8)_SThe value is S in known concentrations, normally in a 10% water solution._C ^*-S_A The transition is measured at a temperature of 10% or less (if not determined) using known methods and the value is extrapolated to 100% of the compound.

TABLE 2

Comparing A and B both possess the same molecular core and the same chiral unit, 2methyl butyl. However, in A, the chiral unit is moving farther away from the molecular core, so it is more free to rotate about the core. The P _S value of A contributes to increasing the freedom of rotation if it is above the order of Magnitude which is less than or equal to that of B.

If the Z-methyl butyl group is more restricted from rotation by attaching it in close proximity to the carbonyl group of the ester as in C, a higher P _S of 3-4 is obtained. It is explained in comparison with J that the properties of the molecular core have a relatively small effect, where very different cores exist but the same order of P _S is obtained.

Comparing C, D and E with the same molecular core, from the relatively unobstructed C-methyl butyl of C with bulky and polar chloro-substituents to the lactate group via Z-chloropropyl, There is a progression of positional disorder that is considerably positionally impaired with respect to rotation. P _S has a corresponding increase.

F and G have a bulky chiral center derived from the amino acids α-alanine. Their P _S values are very high compared to compounds having the same or substantially the same molecular core. F is analogous to lactate E in that the oxygen of the lactate-core ester bond is replaced with NH. Perhaps this is due to some π interaction between the carbonyl and N-only pairs, but other causes cannot be ruled out.

H and I have chiral units derived from (-) menthol and d (-) bornol, respectively. The rotation of chiral methyl units in H is impeded by bulkyisopropyl groups protruding from the ring, and methyl protruding smaller in I impedes the rotation of the chiral ring system. Significantly higher P _S values are found than undisturbed analogs C and D.

J and K have similar molecular cores, but the chiral Z-methylbutyl groups in J are distanced from the core and are free to rotate. Bulky (-) methyl groups at K are used to attach as ester bonds to the molecular core, with a significant increase in P _S.

These results clearly suggest the benefits of the use of positionally impaired chiral centers, and in particular of the use of naturally occurring chiral molecule derivatives.

Claims (14)

In a ferroelectric smectic liquid crystal mixture in which a chiral, first constituent in the mixture is mixed with a second constituent exhibiting a small angle schematic state, the first constituent is stereoscopically related to the main molecular center of the molecule. A mixture comprising at least one compound having an impaired molecular structure. The mixture of claim 1, wherein the degree of steric hindrance is such that the first component produces a maximum of extrapolated spontaneous polarization (P _S ) in the mixture exceeding 10 ncm ⁻² . The mixture of claim 2 wherein the maximum value of P _S is at least ²⁰ ncm ⁻² . 2. A mixture according to claim 1, wherein the first component is or contains at least one derivative of a natural compound containing a chiral group. 5. A mixture according to claim 4, wherein at least one of the derivatives is a derivative of hydroxy-carboxylic acid, amino acid, terpenoid, studoid, sugar or polycarboxylic acid. A mixture according to claim 5, wherein at least one of the derivatives is a derivative of α-hydroxy-carboxylic acid and contains a chiral group of the general formula

Wherein R is alkyl, alkoxy, alkyl or alkoxy substituted by halogen, or a general formula

Wherein (X) is one selected from the group consisting of alkyl or alkoxy, alkylcarbonyloxy or alkoxy carbonyl, halogen, and CN, wherein at least one substituent X is substituted by alkyl, alkoxy, halogen. N may be from 0 to 3, and a may be 0 or 1. 7. Mixture according to claim 6, wherein R is methyl. 6. Mixture according to claim 5, wherein at least one derivative is a derivative of α-amino acid and contains chiral group (i) or (ii) or (iii).

Wherein B is a group that does not contain a hydrogen atom and can form a strong hydrogen bond, or it may be hydrogen, and A is a group containing all hydrogen atoms of CO ₂ H, OH and NH units in residues other than those bonded to A Is a residue of a natural α-amino acid, substituted by B, but not hydrogen, B ′ may be selected from the group B is selected, or may be hydrogen, and a is 0 or 1. 6. A mixture according to claim 5, wherein at least one derivative is a derivative of a chiralterpenoid. The mixture according to any one of claims 4 to 9, wherein the natural compound contains a chiral group having two binding sites, and the derivative has a structure of the following general formula. X-Y-Z Wherein Y is a chiral group, X is R ₁ -S ^9- (A ¹ S ¹ ) _i- (A ² S ² ) _j- (A ³ S ³ ) _k- (A ⁸ S ⁸ ) _r- , Z is-(S ⁷ A ⁷ ) _p- (S ⁶ A ⁶ ) _n- (S ⁵ A ⁵ ) _m- (S ⁴ A ⁴ ) ₁ -S ¹⁰ -R ₂ , wherein R ₁ and R ₂ are each independently selected from hydrogen, alkyl, alkoxy, alkyl, fluoroalkyl fluoroalkyl alkoxy, alkoxy substituted alkyl, alkanoyl, alkanoyloxy, alkoxycarbonyl, halogen, an amine residue, and alkyl-carbonyl-oxy, S ¹ , S ² , S ³ , S ⁴ , S ⁵ , S ⁶ , S ⁹ and S ¹⁰ are each independently a single covalent bond or CO (O) _a , (O) _a OC, CH ₂ , CH ₂ CH ₂ , CH ₂ O, OCH ₂ , CH = N, N = CH, CHD, CH ₂ .CHD and CHD.CH ₂ , wherein D is CN, CF ₃ , CH ₃ or halogen, S ⁷ and S ⁸ each independently represent a single covalent bond or any one of S ¹ to S ^6, S ⁹ and S ¹⁰ are selected as a group other than the COO OOC, S ⁷ may also (CH _{2) q} represent And wherein q is 1 to 12, A ¹ to A ⁸ are each cyclic, which may contain one or more substituent groups, i.e., phenyl, cyclohexyl, bicyclo (2, 2, 2) octane, evacuation, or ruffles , Pyrimidyl, pyridyl, piperidyl, or cyclohexyl containing one or two -CH ₂ -units substituted with oxygen or sulfur, a, i, j, k, l, m, n, p And r are each independently 0 or 1. The mixture according to any one of claims 4 to 9, wherein the natural compound contains a chiral group having one binding site, and the derivative has a structure of the following general formula. X-T Wherein T is a chiral group and X is as defined in claim 10. 11. A mixture according to claim 10 wherein Z is n-alkyl. A liquid crystal display device, comprising injecting the mixture as claimed in claim 1. A liquid crystal display device, comprising injecting the mixture as claimed in claim 5.

Images