CH640257A5 - NEMATIC CRYSTAL LIQUID SUBSTANCES. - Google Patents

Description

The invention is based on the object of creating new nematic crystalline-liquid mixtures which have high chemical and thermal stability, strong intrinsic coloration and pronounced dichroism in the visible spectral range, sufficiently high clearing points at sufficiently low melting temperatures and good lightfastness.

According to the invention, such mixtures contain compounds of the general formulas and / or

, 4th

where R1 = Br-, Cl-, C „H2n + CnH2n + iO- with n = 1 to 10, 30 which form a nematic modification, the desired ones

Properties.

R2 = CnH2n + j— with n = 2 to 10, by producing mixtures of several of these compounds or from these compounds and other R3 = CnH2n + Cn H2n +] 0— with n = 1 to 10, crystalline-liquid compounds can the melting points

35 still sharply reduced and the operating temperature ranges still significantly increased R4 = CnH2n + CnH2n + jO- with n = 1 to 10. The transition temperatures of compounds used according to the invention are in mean. These mixtures can be found in electrooptical tables 1 and 2 below. In the tables, the orders for modulating the continuous or unfolded: K = crystalline solid state; S = smectic modifying light as well as for rendering numbers, characters 40 tion; N = nematic modification; I = Isotropic liquid feeds and pictures are used. was standing. Dots under these symbols show the existence of the

The compounds have a high chemical and ether modification; Lines indicate the absence, mixed stability, a strong intrinsic color and an extreme modification. Parentheses indicate dichroism in the visible spectral region, enough conversions in the unstable region. The conversion-high clearing points at sufficiently low melting temperatures are given in degrees Celsius.

doors and good lightfastness.

Compounds used according to the invention, too The synthesis of the compounds used according to the invention

show no nematic modification, in mixtures fertilize according to the following reaction schemes: with other compounds used according to the invention, A. 3- (4-Subst. phenyl) -6-n-alkyl-l, 2,4,5-tetrazine

Version 1:

■ QC

N-Nk n) -R2

N-N '

I I

H H NaNO 2 /

I.

r, - <2> - <n ~ n> 2

v— 'NN = N ^

acetic acid

257

Variant 2:

(X = Cl, OC2H5)

/ - \ / NH-NHs. R'-OO / -c N: -R2

O O

PCL

N ^ C-R2 ci Cl n2h4 • h2o

"'- © ^ nnINV * 1

I I H H

NaNOi / acetic acid v— 'xn = n /

B. 3,6-bis (4-subst.-phenyl) -l, 2,4,5-tetrazine r3

%

oc2h5

nh

HCl

N2H4 • H, 0

r. HCl '

H H

\

NH,

NuNO: / Essissäure

640 257

C. 3- (4-N-Alkyloxyphenyl) -6- (4-Subst. Phenyl) -1,2,4,5-te-trazine

/ OC2H5 C ^ NH HC1

; NH

NH,

N, H4 • H2O

HCl

H H

N aN 02 / acetic acid

- © O © -

I I H H

Table 1

\ N = N /

R2

No.

r1

r2

k s

N

1/1

c6h, 3

c7h15

. 41

(.27)

1/2

c4h9o c5h "

. 55 ')

-

.59.5

1/3

c4h9o c6h13

. 49

-

. 57

1/4

c4h9o c7h, 5th

. 47

(.43)

. 62

1/5

c5h „o c4h9

. 483)

.49

1/6

c5H "o c5h"

. 60

(• 59.5) 2>

1/7

c5h „o

C6H13

. 65

- -

(, 58.5) 2>

1/8

c5h „o

C7Hi5

. 49

. 52.5

. 63

1/9

c6h13o c5h "

. 55

. 68

-

1/10

c6hI3o c7h15

. 58

. 744)

. 76

40

45 1} Melt an unstable solid modification at 53.5 ° C

2) Monotropic nematic

3) Melt an unstable solid modification at 43 ° C

4) A transformation is observed in the smectic range at 65-68 ° C

Table 2

No.

r3

r4

k s

N

2/1

c4h9

c4h9

. 170

_ _

. 172

2/2

c5h "

C5Hu

. 163

- -

. 172.5

2/3

c6hi3

C6Hi3

. 156.5

- -

. 157.5

2/4

c7h15

c7h15

. 150

- -

. 160

2/5

c8hi7

c8h17

. 145

- -

. 151

2/6

c9h19

c9h19

. 139

145

. 151.5

2/7

cioh2i cioh21

. 136

146

. 146.5

2/8

ch3o ch3o

. 247

-

. 253

640257

6

Table 2 (continued)

r3-® <1 "kX2K

No.

R3

R4

K

S

N

2/9

c2h5o c2h5o

. 238

-

-

. 268

2/10

c3h7o c3h7o

. 203

-

-

. 224

2/11

c4h9o c4h9o

. 190

-

-

. 226

2/12

qhno c5h „o

. 181

-

-

. 210

2/13

c6h13o c6h13o

. 163

181

. 207

2/14

c7h15o c7h15o

. 146

183

. 197

2/15

c8h17o c8h17o

. 131

187.5

. 195

2/16

c9h190

c9h19o

. 120

188

. 190

2/17

QoH2] 0

C, oH210

. 111

189.5

- -

2/18

c4h9o c8h17

. 127

132.5

. 180

2/19

c6h130

c9h19

. 119

153.5

. 175

2/20

c8h17o c8h17

. 126

161

. 172.5

Execution examples

example 1

3- (4-subst.-phenyl) -6-n-alkyl-l, 2,4,5-tetrazine (variant 2)

In a three-necked flask with thermometer, stirrer and distillation attachment, 0.03 mol of N-alkanoyl-N '- [4-subst.-benzoyl] hydrazine is mixed with 20 g (0.09 mol) of PCL5 and in vacuo and with stirring to 140 ° C heated. The reaction mixture liquefies and POCl3 and PC15 distill off. The reaction is complete when POCl3 is no longer produced. After cooling, the contents of the flask are taken up in ether and ice is carefully added while cooling. The ether extract is then washed with water and bicarbonate solution, dried over Na2S04 and the solvent is removed on a rotary evaporator. The 1,4-dichloro-l- [4-subst.-phenyl] -4-alkylazines are obtained as yellow-brown oils and are further processed as raw products.

The oil is suspended in 50 to 80 ml of absolute ethyl alcohol and cooled to -5 ° C. Then enough ether is added until a clear solution results (approx. 20 ml). While stirring, 4 g of 80% hydrazine hydrate in 20 ml of ethyl alcohol are added dropwise so that the temperature does not exceed 0 ° C. Then it is stirred for two hours at room temperature. The resulting dihydrotetrazine is suctioned off and oxidized to tetrazine with NaN02 / acetic acid. The product is purified by recrystallization or column chromatography. Yield: 10-20% of theory Th.

Example 2

3- (4-subst.-phenyl) -6-n-alkyl-l, 2,4,5-tetrazine (variant 1)

0.005 mol of 4-subst. Benzimidoester hydrochloride, 0.015 mol of amidine hydrochloride and 10-30 ml of hydrazine hydrate (80%) are stirred at room temperature for 2-5 hours. The contents of the flask are then poured into water, the precipitate is filtered off and washed.

The precipitate is suspended in 30-40 ml of 10% NaNO 2 solution, covered with 70 ml of ether and oxidized to tetrazine with small portions of 10% acetic acid.

The ether extract is washed, dried with Na2S04 and the solvent is removed on a rotary evaporator. The residue can be purified chromatographically using silica gel, using methylene chloride as the eluent. Yield: 20-50% of theory Th.

Example 3

3,6-bis (4-subst. Phenyl) -l, 2,4,5-tetrazine 25 0.02 mol of 4-subst. Benzimidoester hydrochloride are mixed with 10 g of 85% hydrazine hydrate for one hour on a water bath warmed up. After cooling, the yellow crystal mass of the substituted dihydro-s-tetrazine is suction filtered and washed with ether.

30 The precipitate is suspended in 30-40 ml of 10% NaNO 2 solution, covered with 70 ml of ether and oxidized to small amounts of 10% acetic acid with stirring to form s-tetrazine. The tetrazine formed dissolves in ether. The oxidation is complete when the yellow starting product is used up. The ethereal phase is separated off, washed with water, dried with Na2S04 and then the solvent is distilled off on a rotary evaporator. The residue is recrystallized from dioxane or ethyl alcohol / dioxane (7: 1). Yield: 40-70% of theory

40

Example 4

3- (4-n-alkyloxy-phenyl) -6- (4-substituted-phenyl) -l, 2,4,5-te-trazine

0.005 mol of 4-n-alkyloxy-benzimidoester hydrochloride, 45 0.015 mol of 4-sub-benzamidine hydrochloride and 8 ml of 80% hydrazine hydrate are stirred for three hours on a water bath at 80 ° C. and left to stand overnight. The precipitate is filtered off and washed with water and ether.

50 For the oxidation, the precipitate (dihydro-s-tetra-zine) is suspended in 30 ^ 40 ml of 10% sodium nitrite solution, covered with 70 ml of ether and mixed with small portions of 10% acetic acid with stirring. The oxidation is complete when the yellow starting product is used up and the tetrazines are dissolved in the ether.

The ethereal phase is separated off, washed with water, dried with Na2S04 and the solvent is distilled off on a rotary evaporator. The residue is chromatographed on silica gel (0.05-0.2 mm core size, Merck) with benzene / Cy-60 clohexane (1: 1). The resulting 3 tetrazines are completely separated on a separation column measuring 100 x 3 cm. The yield of asymmetric tetrazine is 10-50% of theory

65

Example 5

An approximately 10 μm thick oriented layer (P layer) is produced from the connection 2/18 between transparent, electrically conductive electrodes. When radiating with

white, polarized light this layer appears pale yellow when the direction of oscillation of the light coincides with the preferred direction of the P-layer. After applying an electrical voltage of 15 V at 163 ° C, the layer is reoriented, which is then colored intensely red-violet. The switching can be repeated as often as required.

Example 6

A compound layer is produced from compound no. 1/4 in analogy to example 5. This layer appears colorless without an electric field if the direction of oscillation of the incident polarized light coincides with the preferred direction of the P layer. If an electrical voltage of 15V is applied at 56 ° C, the layer is colored red-violet after reorientation. The switch-on time is 30 ms, the switch-off time 90 ms. A color change from faint pink to red-violet and vice versa can also be observed in white, non-polarized light. If a green filter is switched on in the beam path, a change from light green to black occurs after the application of an electrical field.

Example 7

A mixture of the following compounds is produced:

-4-n-propyl-cyclohexane carboxylic acid -

-4-cyanophenyl ester

-4-n-butyl-cyclohexane carboxylic acid

-4-cyanophenyl ester

4-n-pentyl-cyclohexane carboxylic acid

-4-cyanophenyl ester

Connection No. 1/4

This mixture is nematic and colored red at room temperature. It shows a negative dichroism. An approximately 20 µm thick P layer is produced from the mixture between transparent electrodes. In the white, linearly polarized light, the direction of oscillation of which corresponds to the preferred direction of the P-layer, the transmitted or reflected light appears pale pink. After switching on an electrical voltage of 3 V, an intense red color appears. This arrangement was 600 hours

10th

15

r 640 257

exposed to daylight. Compared to the original state, no change in extinction was discernible in the visible spectral range.

ï Example 8

The mixture according to Example 7 contains 0.9% by weight of the yellow dye “Wolfen 6”, which has the following chemical constitution.

ch3- (Ö> -N = Y ^ -CH3

HO N

I.

5.5 mol%

24 mol%

25.5 mol%

25 mol%

and has a positive dichroism. A P layer produced from 20 of this mixture appears yellow in the transmitted or reflected light if the preferred direction of the P layer and the direction of oscillation of the incident polarized light match. After switching on an electrical voltage of 3 V (50 Hz), the color changes to red. Fig. 1 shows the dependence of the permeability of a cell filled with this mixture on the wavelength at 20 [in the layer thickness:

1- in field-free condition,

2- after applying 1.2 V AC voltage,

30 3- after applying 1.5 V AC voltage,

4- after applying 3.0 V AC voltage,

5- after applying 10 V AC voltage.

35 Example 9

In addition, 0.4% by weight of indophenol blue are dissolved in the mixture according to Example 8. Indophenol blue is a dye with a positive dichroism. A 20 μm thick P layer is produced from the mixture obtained in this way. If the preferred direction of this layer and the direction of oscillation of the incident polarized light match, the transmitted or reflected light appears green. After switching on an AC voltage of 3 V is the layer colored red.

C.

1 sheet of drawings

Claims (3)

640257 2nd PATENT CLAIMS of conspicuous light as well as for the reproduction of numbers, 1. Nematic crystalline-liquid mixtures for electro-optics and images, characterized in that they have connective arrangements for modulating the continuous or fertilizing of the general formulas r1 - ^) ^ n = nx5 "r2 and / or r3- <Ö> <n.nME> -r4 where R1 = Br, Cl-, CnH2n + 1-, CnH2n +, 0- withn = 1 to 10, R2 = CnH2 „+] - with n = 2 to 10, R3 = CnH2n +] -, CnH2n + iO- mitn = 1 to 10, contain further crystalline-liquid or non-crystalline-liquid substances, in particular dyes. 3. Nematic crystalline-liquid mixtures according to patent 10 R4 = CnH2n + 1-, CnH2n +, 0- with n = 1 to 10 mean contain. 2. Nematic crystalline-liquid mixtures according to claim 1, characterized in that they addressed in addition to the compound 15 fertilizers of the general formulas 1, characterized in that they are in addition to compounds of the general formulas 2 -, / N = N. R and / or R and / odcr r3- <§> - <I ".Ixô) -r4 Contain dyes with positive dichroism. sensors, whereby part of the incident light is lost as a result of absorption. Special technological difficulties In both processes, the result is that the Layer thicknesses within very narrow limits (approximately ± 1 μm). The invention relates to nematic crystalline-liquid mixtures which must be kept constant. The interference interference observed for electro-optical arrangements for modulating the color are also usually very sensitive to continuous or striking light, in particular to fluctuations in the applied voltage and the tinted rendering of numbers, characters and images. temperature. These disadvantages can be avoided in part with a characteristic of the known technical solutions 40 which are already known. Serve It is known that with the aid of an electric field, the electro-optical cells with twisted nematic or cho preferred orientations of nematic crystalline-liquid substance esterin layers of weak twist can be changed to colored zen. This change in orientation modulation of light. The crystalline liquid can be used in various ways for light modulation, in particular a positive dielectric anisotropy that is as high as possible, for the colored representation of numbers or characters and image 45 a suitable dye in the form of a non-crystalline rendering. A known method is based on liquid or a nematic, smectic or cholesterol-based, nematic crystalline liquid substances with a negative niche compound added. Between crossed Polarisa anisotropy of the dielectric constant between two gates, these cells result in colored light in transmitted or reflected light Glass panes, which have been provided with a transparent, electrically conductive light and after the application of an electrical field triggering the coating, are homeotropically oriented / F. Kuschel, D. Demus, G. Pelzl: DDRWP 116 116 /. ren (N-layer). Although with this method the layer thickness and chip If this arrangement between two crossed polarization dependencies of the color produced is brought to a greatly reduced value, then after the application of an electrical voltage, the disadvantage remains that the distortion results in the continuous or reflected light in color using two polarization filters. (DAP-EFEKT) /M.F. Schiekel, K. Fahrenschein: Applied 55 A method is also known that the colored light-Physics Letters 19 391 (1971) /. modulation using a liquid crystal cell Another known method is based on the fact that only one polarizer is permitted. This method, which is based on nematic liquid with positive anisotropy of the dielectric- the guest-host effect, / GH Heilmeier, LA is oriented to the static constants in such a way that the longitudinal axes serve noni: Applied Physics Letters 13, 91 (1968) / On average, the molecules are in a direction parallel to the one dye with a positive dichroism, which are arranged in a closing electrode (P layer). If nematic liquid is dissolved. If this crystalline-liquid P-layer between crossed polarizers in a dioscopic mixture has a positive dielectric anisotropy, it is brought into the neutral position and an electrical P-layer is produced on the electrodes. If this P-layer is applied to the voltage, the color of the transmitted light can appear colored in polarized light if the direction of the light or the reflected light is controlled with the help of the voltage transition torque of the embedded dye molecules (“DP effect”) / H . Zaschke, H. Schubert, F. coincides with the direction of vibration of the light. Kuschel, F. Dinger, D. Demus: GDR WP 95 892 /. After switching on an electrical voltage, a turns on Both methods require the use of two polar changes from colored to weak or colorless observed. 3rd 640 257 For visual reasons, it is more advantageous if the crystalline liquid mixture has a negative dielectric anisotropy and an N layer is assumed. Then this layer appears colorless or weakly colored when de-energized; on the other hand, it becomes colored if it is uniformly reoriented by an electric field. The goal of producing an electro-optical arrangement in which the electrically controlled areas (numbers, letters, etc.) are strongly colored and stand out in contrast to their field-free surroundings cannot be achieved with this method, or can only be achieved incompletely. This is due to the fact that the known nematic liquids suitable for components with negative anisotropy require excessive operating voltages (10 V and more). Another disadvantage of the known methods for the color modulation of light is that the dyes used are often poorly soluble in the nematic liquid. In these cases, only weak color contrasts are achieved. There is also a risk that the dye will crystallize at lower operating temperatures. Furthermore, the light fastness of the dyes previously used .N-N "® < N = N insufficient, so that the color contrasts decrease with increasing operating time. Aim of the invention 5 The aim of the invention is mixtures with new nematic crystalline-liquid compounds for electro-optical arrangements for modulating the continuous or striking light and for reproducing numbers, characters and images, which provide strong color contrasts at low operating voltages and low operating temperatures. State the nature of the invention