DE2257588A1 - CRYSTALLINE LIQUID NEMATIC SUBSTANCES - Google Patents

Description

VEB Werk für Perns ehelektronik O O C T C ο ο

116 Berlin-Oberschöneweide - £ 4P / OqQ

Ostendstrasse 1-5

Crystalline liquid nematic substances

The invention relates to the use of crystalline liquids nematic substances in electro-optical arrangements to modulate the continuous or incident light and as a solvent in spectroscopy and as stationary Phase in gas chromatography.

It is known that nematic crystalline liquid substances are oriented in electric fields can. This possibility for orientation can be used in electro-optical arrangements for light modulation to be used. It is also known that the molecules of added substances orientate in nematic liquids will. This orientation "ran foreign molecules" is with the help of spectroscopic investigations UV / VIS spectroscopy, nuclear magnetic resonance spectroscopy and electron spin resonance spectroscopy to determine the anisotropy properties of the molecules very advantageous. It has also been suggested the orientability of dichroic molecules in nematic liquids in electro-optical arrangements to exploit the modulation of light · Nematic liquids have also been used with success as Separating liquids used in gas chromatography.

It is also known that twisted nematic layers form the structure of electro-optical components allow.

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Purely the application of liquid nematic crystals it is often necessary just a little above room temperature or even to work at temperatures below room temperature. The so far known substances either have melting points well above room temperature or they are due to sensitive groups in the molecules to thermal and chemical influences as well as electrical fields inconsistent, sometimes they have disruptive ones in the visible part of the spectrum Absorption bands. In order to get to systems with a lower melting point, eutectic mixtures can be used use * For some previously known classes of substances, the lowering of the melting point is achievable but only slightly.

The object of the invention is to use low-melting, stable, colorless nematic crystalline Liquids in electro-optical arrangements also with a twisted structure, as well as for Spectroscopy and gas chromatography.

It has been found that various new derivatives of pheny! Pyrimidine of the general formula

(R _1, Rp are the same or different substituents .ie For example, C _n H _{2n + 1} -, C _n H _{2 NH,} O, C _n

where η = 1 to 12) in electro-optical arrangements for modulating the passing or incident light, as well as a solvent in spectroscopy

10 <) B 2 6/0 7 4 6

and as a stationary phase in gas chromatography can be applied. The invention Substances melt at low temperatures crystalline-liquid ηemetic phases. By Preparation of mixtures, preferably eutectic Mixtures of two or more phenylpyrimidine derivatives have very low melting points. drigt while maintaining the beneficial properties of the pure substances. To the pure or mixed compounds according to the invention can ■ nen other substances, such as B. dichroic dyes or other crystalline liquid compounds are added will.

The phenylpyrimidine derivatives are produced by condensation of p-substituted benzamidine HCL with n-alkylmalonic esters or n-alkoxymalone esters in the presence of halium methylate, conversion of the substituted 4,6-dihydroxypyrimidines in the corresponding dichloropyrimidines and subsequent dehalogenation in good Yields obtained as colorless crystals.

The following reaction scheme shows the synthesis route!

NH

H ₅ C ₂ OOC.

■ »

CH-R,

09826/0746

According to the invention, the derivatives of phenylpyrimidine for the creation of nematic layers with twisted structure made by rubbing the electrode surfaces and setting a certain Angle of the rubbing direction of the two electrodes, preferably 90 °, is generated. The use of mixtures, preferably eutectic mixtures, is particularly advantageous of 2 or more phenylpyrimidine derivatives or mixtures with the addition of other crystalline liquid or non-crystalline liquid substances, z. B. p-cyanobenzal-butylaniline, p-chlorobenzalphenetidine, Diphenyl ether, n-octylbenzene. The liquid crystal substance can advantageously after the assembly of the rubbed electrode surfaces are introduced into the cell «

Advantages of the compounds according to the invention are the low melting points and the marked reduction in melting point in mixtures of two or more of these compounds. They are colorless and stable even when heated for hours at temperatures above 100 ^° C., do not decompose through the action of air, moisture or the action of light and remain unchanged even after the action of electrical fields (direct or alternating voltage) for days. In the nematic state they have a positive anisotropy of the dielectric constant. In addition, these compounds are colorless.

The invention is explained in more detail below by means of 7 examples explained.

Example 1:

5-n-Hexyl-2- (4-n-hydroxyloxyphenyl) pyrimidine. To dissolve 3.5 g (0.15 mol) of sodium in 100 ml of abs. 0.05 mol of pn-hexyloxybenzamidine-HCl ( _{dried over P 3} O ₅ ) and methanol in succession

■ '- 5 309826/0746

MqI n ^ exy ^ stalosjesteF i§geken * ünte! Clocks

Man & Stuaten on SQ ^a G (old temperature) can be put afterwards, iifcer laughs. With concentrated- * tesi HCiJ, yitijpd da® lyrimidian precipitated, filtered _tl ~ filtered off * wit lapse **, ÄllüeiliQl viiid ether is called ISO ⁰ G fetpQtQteft »for the eel ^ ae becomes: aoiei

0.05 lol 5 * n «He ^ l ^« C ^^ B ^ he ^ lQxyj) heB ^ dihydroxy ^ yrimgldiri (loh ^ radWkt) * t2 ml I and 1QO raO, BOGl ^ be | Q Sti * nden untej? Eloleftoft cooked ·. Ba & tihe ^ eich ^ s & igei PQGl ₁ ^ wi ^ d ίτ hot oily Iftctestanfl yitter üüweEfc m £ eto demiaeh

tOO g Sig gased ,, $ & $ alkaliaehej; with Äthe ^ eaetrahiei't ·, ler Äthiej? extj? akt wij? di t- ^ 50 m] ^ halhkon ^ eifetr $ eite ^ Mß3k aws ^ ms ^ hiittelti. mit gewas _f chestit mtt ^ θ ^^ fe ^ oiJkneit; y ^ dl after; #aa ah <| e®% i | Mei? ty B ^ e received- E- ^ iataJlhrei; awa Jlk

309.8 26/07

Example 2:

Table 1 shows examples of the melting clearing points of the invention! connections dkgr

general formula

indicated.

Table 1 Ir. R.

1IpC ⁰ C)

amektiscii / nematiach

^C 10 ^H 21 °

^C 6 ^H 13

4th

56.5.

60.5 61

63 65

60 * 5

88 '

Example 3:

In Table 2 are. Examples of binary mixtures of the er inventive compounds included.

Table 2

Miaemung Substance- Hol % ff.C ° C)

Mr. Mr*

t 2

68.5 ν * 5

3t

74 26.

1 4

60

5 »

- f

30982 & / 074S

Example 4:

The compounds according to the invention and their mixtures can be used in electro-optical arrangements of the following design (Fig.1):

In a cell consisting of 2 glass panes 2; 3 with electrically conductive 'transparent electrodes 4; 5, There is a nematic liquid 1. Distance the electrodes 4; 5 is fixed by fine Teflon or polyethylene strips 6 · The cell can be in the. direction indicated by .light shone through, which also passes through the polarizer 7 and the analyzer 8. The two conductive electrodes 4; 5 were Rubbed the substance evenly before filling and inserted so that the rubbing direction is parallel to each other Btehen. The nematic liquid 1 is oriented then with their preferred direction parallel to the rubbing direction the rubbing direction and the direction of oscillation of the polarizer 7 form an angle of 45 ° A uniformly colored field of view results between the crossed polarizer 7 and the analyzer 8. By applying direct or alternating voltage, the field of view passes through depending on the applied voltage Stress is a series of interference colors and eventually becomes dark.

309826/0746

Table 3

Mixture I shows at 20 C and an electrode hub t and of 10 / Um with 50 Hz alternating voltage following «« Behavior ι

Soannunp; (V) color order * 1st order 0 Higher orders 6.1 light yellow ν 6.6 light green) 7.5 light red) 3 «order 8.0 green < 8.6 blue ) 9.7 Red ) 11.3 yellow 2nd order 13.4 green 15.6 blue 19.8 20th Red ) yellow < gray to black)

The cell shows after 2000 hours of operation

20 C no change in properties.

Example 5 «

The use of crystalline liquid phenylpyrimidine derivatives or mixtures of these compounds for modulating the intensity of passing or incident light is intended in an exemplary embodiment can also be described in Fig. 1.

The cell has a structure as already described in Example 4. The two electrode surfaces 4; 5 become also rubbed before assembling the cell and pouring in the nematic liquid and such used so that the rubbing directions form an angle of preferably 90 with each other

- 9 ■ -

309826/0746

After filling in, the nematic liquid orients itself with its preferred direction in the vicinity of the electrode surfaces 4; 5 parallel to the rubbing directions. On the whole, the result is a twisted one Structure. The arrangement, which still consists of the polarizer 7 and the analyzer 8, is shown in FIG Direction indicated shines through with light.

Depending on the angle that the planes of oscillation of polarizer 7 and analyzer 8 form with one another, exist z. B. the following two possibilities for intensity modulation of the light passing through (Fig. 2):.

Case a: Are the planes of oscillation of polarizer and analyzer 8 in parallel, the intensity of the emerging light is very small. By applying a direct or alternating voltage of 5 to 7 V to a cell with an electrode spacing of 10 µm, the optical activity disappears; the continuous Light shows maximum brightness.

Case b: If the planes of oscillation of polarizer and analyzer 8 crossed, then that has a continuous Light maximum brightness when de-energized. When voltage is applied on the other hand, darkening in the direction of radiation.

In Fig. 2 the intensity of the transmitted light (in arbitrary ^ units) is ^{plotted against the applied voltage for the cases a%} and b. The cell used contains a mixture of 68.5 mol % 5-n-hexyl-. 2- (4-n-hexyloxyphenyl) pyrimidine and 31 "5 mole% n-5-hexyl-2- (4-n-nonyloxyphenyl) pyrimidine, which is nematic in the temperature range of 4 ° to 60 ⁰ C, in a 10 to thick layer. It is used at 20 ^° C., 50 Hz alternating voltage.

The electric field of the arrangement mentioned can be replaced by a magnetic field.

-10- 309 826/07 46

Example 6:

The use of the compounds according to the invention can also in a cell operated in incident light mil; one reflective back electrode. The electrodes can consist of segments that can be individually connected to the voltage and thus playback colored characters and numbers. By using strip-shaped conductors on both electrodes in a crossed arrangement, the nematic liquid can be controlled point by point and made possible the reproduction of characters and images.

Example 7 <

The cell according to Fig. 1, but without the polarizer pad Analyzer is with mixture 1 with the addition of 1% diethyl red or another dichroic dye filled. While there is no voltage applied white light appears red after passing through the cell, the color changes at 20 V. AC voltage from 50 Hz to yellow.

- 11 -

309826/07

Claims (5)

225158; Patent claims s Crystalline liquid nematic substances for electro-optical Arrangements for modulating the transmitted or incident lighta and as a solvent in of spectroscopy, and as. stationary phase in the gas * Chromatography ,, characterized in that new, Derivatives of pheny! Pyrimidine of the general formula in which R, R are identical or different substituents, ^z · ^B · ⁰ An ₊ I ' ⁰ An ₊ I ° "· ⁰ Ax ₁₊ I ⁰⁰⁰ ' ⁰ An ₊ I« * · ^where η * is 1 to 12, can be used. 2. Crystalline liquid nematic substances according to claim 1, characterized in that mixtures of two or several compounds according to the invention can be used. 3. Crystalline liquid nematic substances according to claim and 2, characterized in that the pure or mixed compounds according to the invention, further substances, such as dichroic dyes or other crystalline liquid compounds, are added. 4. Crystalline liquid nematic substances according to claim 1 to 3, characterized in that they are used for production of nematic layers with a twisted structure can be applied. 5. Crystalline liquid nematic substances for electro-optical arrangements according to claim 1 to 4, · characterized characterized in that the liquid crystal substance after the assembly of the rubbed electrode surfaces in ^ the Cell is introduced. 309 8 2 6/07 U. S