DD151950A1 - APPLICATION OF CRYSTALLINE-FLUFFY DYES - Google Patents

Abstract

The invention relates to the use of novel crystalline liquid dyes in nematic crystalline liquid mixtures in optoelectronic devices based on the guest-host effect. The aim of the invention are crystalline liquid dyes for the guest-host effect. It has been found that, as crystalline-liquid dyes for the guest-host effect, derivatives of s-tetrazine of the general formula can be used advantageously.

Description

22 23 6 5

Application of crystalline liquid dyes

Field of application of the invention

The invention relates to the use of novel crystalline liquid dyes in nematic crystalline liquid mixtures in optoelectronic components based on the guest-host effect for the modulation of the continuous or incident light, in particular for the color reproduction of numbers, characters and images.

Characteristic of the known technical solutions

Liquid crystals can be reoriented due to their dielectric anisotropy in electric fields. If a dichroic dye is added to the liquid crystal, it is possible to switch between a color and the colorless state or another color. This

The process referred to as guest-host effect can be used to construct optoelectronic devices

 G.H. Heilmeier, L. A. Zanoni: Applied Physics Letters 1_3, 91 (1968). ,

It has already been proposed to use crystalline liquid derivatives of tetrazine, which have a negative dichroism, as guest-host dye dyes, in order to obtain high contrasts in the devices On the other hand, the solubility of the dyes must still be sufficiently high, even at low temperatures

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"hitherto" known dyes are not optimal in view of these requirements.

Object of the invention

The aim of the invention are crystalline liquid dyes for the guest-host effect, which have high contrasts.

Presentation of the essence, the invention

The invention has for its object j crystalline liquid dyes with high clearing points and sufficient solubility at low temperatures to find. It has been found that as crystalline-liquid dyes for the guest-host effect derivatives of s-tetrasine of the general formula I.

N-N.

where R ¹

> ^C n ^H 2n + 1 ° - ' ^C n ^H 2n + 1 ^0C0 ° -' ^Έ ~> ^C1 -> J-, NC-, O ₂ N-

R ⁵ β H, F, Cl, Br, CH ^

with η = 1 to 12 ',

Due to their high clearing points and good solubility even at low temperatures are very suitable and therefore can be used advantageously.

The synthesis of the tetrazine derivatives takes place according to the following scheme:

U, 3y-877804

_ 3 - 2 2 2 3 6 5

HO- <n> -C "HCl + (

HN ^/

(Oxidation)

II ~

R ¹ -COO

(Esterification n.Einhorn)

Exemplary embodiments Example 1

J-alkyl-δ - ω-hydroxyphenyl-S-tetrazines II variant A:

OcO1 mol of arylimide ester hydrochloride are dissolved in 10 ml of pyridine yellow, with 10 ml of 85 # hydrazine hydrate replaced and stirred for 10 minutes. Then, o, 03 mol of alkaneamine hydrochloride, dissolved in 10 ml of pyridine, added with stirring and heated for 15 minutes on Bückfluß. The mixture is then stirred for 20 hours at room temperature and the reaction mixture is poured into 200 ml of water for work-up.

The precipitated dihydro-s-tetrazine mixture is filtered off, suspended in 100 ml of ether, underlaid with 50 ml of 10 # NaNOg solution and slowly added dropwise with stirring 10 $ acetic acid. The red tetralin dissolves in the ether. After completion of the reaction is washed neutral, Tom insoluble diphenyl-s-tetrazine filtered off and the ether distilled off on a rotary evaporator. The residue is recrystallized several times from ethanol.

- 4 - 2 2 2 3 8 5

^ Variant:

.0.01 mol of arylimide ester hydrochloride are added with stirring and water cooling with 15 ^ nI 85 fS-hydrazine hydrate. After the formation of a clear solution, 0.03 mol of alkaneamine hydrochloride are added and the mixture is stirred at room temperature for 20 hours The dihydrotetrazene mixture is filtered off with suction, washed thoroughly with water and worked up analogously to Variant A.

In this way, e.g. produce the following representatives:

10 • HO-C H ₁ ^ r ^ _{2n + 1} II η Yield % F ⁰ C 1 3 6 50 48 41 228 181 148 15 Example 2

Trans - ^ - Alkylcyclohexancarbonsäure- or 4-Subst.-benzoe acid 4- / 6-alkyl-tetrazin-3-ylJ-phenyle ster I

-0.01 mol of the subject compound II are reacted in 1.5 ml of pyridine with cooling with 0.015 mol of the acid chloride in question. The reaction proceeds spontaneously, with warming. After 0.5 hours, pour into seswasser and acidified with conc. HCl on. The ester is filtered off, washed with bicarbonate solution and recrystallized from isopropanol to KlärpunktkonstanE. The yields are 50-95 Sun.

25-The following tables show examples of the substances according to the invention with their Umvrandlungstemperaturen. It "means ϊ

K = crystalline-solid; S ₁ , S ₂ = smectic 1, smectic 2; N - nematic; is = isotropic liquid «

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table 1 η 2 ^C m ^H 2rn ₊ 1 - <!> - ^C00 - ^ N-N ^C n ^H 2n + 1 212 I - (Dec.) 1 κ S ₁ S ₂ is 195 ( ^M ) m 1 * 167 - K 219 (») 1 1 , 102 '- • 211 ( ^w ) 2 1 , 112 - • 211 ( If \ 3 1 , 102 - * 203 («) 4 1 , 107 - · ' 171 VJL 3 , 102 - φ 156 6 6 , 104 - φ 186 2 3 , 102 - φ 176. 2 6 , 92. 111. φ 182 4 3 , 89 - 127. 172 4 6 , 58. 123. 149. 6 , 40. 130. 152. 6 167. !Table "-Iff

R η , 140. 130 - S ₀ N is - ^C 2 ^H 5 C ₂ H ₅ 1 3 , 101 - .194 .171 φ φ C ₂ H ₅ 6 , 123 - .155 • ^C 6 ^H 13 1 .105 .- 60) .177 φ ^C 6 ^H 13 3 .78 ( (Dec. .160 φ ^C 6 ^H 13 6 , 144. 223-225 , 162 , 97.5. 147.5 φ ^C 5 ^H 11 ° CN 1 1 , 134 , 204) φ CN 6 - (Zers.)

, JII.

Ο77ΟΠ ι-.

2 2 2 3 8

A colorless nematic base coat, "consisting of 20 wt. % C ₃ H

19 "C ₄ H ₉ - (H

22 ^IS C ^ H

13.3 » ^C 4 ^H

, 25.7 · C ₄ H ₉ () → ₆₁₃

N = N 17 wt .- ^ ^c ₂ H = - (LFY-C00- ^ r ^ -. ^ J ^ "* ^CH 3 sugemischt.

The mixture "has a melting point of -7 to -1 ⁰ C and a clearing point of £ J4 ⁰ C.

The mixture is planarized between two transparent electrodes, i. the molecular director is uniformly aligned parallel to the electrode surfaces. If the incident light is polarized by a polarizer parallel to the direction of the director, then one can observe "contrasting color shifts from pale pink to intense red-violet" when an electric field is applied.

Electro-optical data of such a cell (layer thickness 15> μm):

Sohv / ell voltage: 1.3 volts Operating voltage: 4 "volts

Anchor sides (50 % intensity change): 639 ms (3 volts)

  482 ms (4 volts) 125 ms (6 volts)

Decay side (50 % intensity change): 350 ms.

i * i -1 ~ 7 η r \.:.

Claims (1)

22 23 6 Claim for invention ".!: 1. Application of novel crystalline-liquid dyes for the guest ~ host effect in nematic crystalline liquid mixtures for optoelectronic components based on tetrasin derivatives, characterized in that compounds of the general formula I CH v; oDei R ¹ = B Ί0 Br, J, NC, R ³ = H, F, Cl, Br, η = 1 tis 12 "mean,
used.