EP0308444A1

EP0308444A1 - PYRROL 1.2-b]AZINES

Info

Publication number: EP0308444A1
Application number: EP88902480A
Authority: EP
Inventors: Heinz DÜRR; Volker Bach
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 1987-04-01
Filing date: 1988-03-21
Publication date: 1989-03-29
Also published as: WO1988007702A1; DE3710889A1; JPH01502854A; US4983324A

Abstract

Des matériaux optiques non linéaires contiennent l'élément structural ayant les formules générales (I) et/ou (I'), dans lesquelles R1, R2, R3, R3', R4, R5, R6, R7 et Z ont la signification décrite dans la première revendication.Nonlinear optical materials contain the structural element having the general formulas (I) and/or (I'), in which R1, R2, R3, R3', R4, R5, R6, R7 and Z have the meaning described in the first claim.

Description

Pyrrolo [1.2-b] azines

The invention relates to new polymer materials with nonlinear optical properties and methods for their production.

Non-linear optics deals with the interaction of electromagnetic fields in different media and the associated creation of new fields with changed properties. Materials with non-linear optical properties have a field strength-dependent dielectric susceptibility of the second order, which results in a number of dispersive processes: the frequency doubling (second harmonic generation = SHG) allows the generation of light of half the wavelength compared to the incident light; the electro-optical effect (Pockels effect) enables the refractive index to be changed when an electric field is applied; Methods of sum and difference frequency mixing as well as frequency division allow the continuous tuning of laser light.

A large number of technical applications result from the effects listed above. Electro-optical switches, frequency and intensity control in laser technology, holography as well as the areas of information processing and integrated optics represent areas of application for materials with non-linear optical properties of the second order. Materials with 3rd order electrical susceptibility functions are suitable for the production of purely optical switches and thus as waveguides for the construction of purely optical computers.

In order to be suitable for use in the field of second-order non-linear optics, such materials have to meet a number of requirements.

In addition to a non-centrosymmetric molecular arrangement in the

Crystal requires technical usability, the highest possible values for the dielectric susceptibility X ⁽²⁾ .

A number of inorganic substances such as Potassium dihydrogen phosphate or lithium niobate shows non-linear optical properties. However, all of these connections have various disadvantages. In addition to insufficient values for the second-order dielectric susceptibility, inorganic compounds often lack sufficient photostability when treated with high light intensities, or are difficult to manufacture and process.

Organic compounds of the nitroaniline type are known from Garito et al., Laser Focus 18 (1982) and EP-0091 838. However, their relatively good values for the photochemical stability and the dielectric susceptibility of the second order go hand in hand with poor crystallizability and poor mechanical stability. In particular, the production of thin layers, as required by the integrated optics, does not succeed with these materials. Polymers are characterized by high mechanical resistance and good chemical stability. Molecules with non-linear optical properties attached to the polymer structure or dissolved in polymers should therefore have advantageous values for the dielectric susceptibility in the non-centrosymmetric environment.

Polymers with non-linearities of the second order can be produced by applying an external field to films heated to above the glass temperature and doped with statistically oriented molecules. This leads to polarity of the embedded molecules, which gives the polymer medium an anisotropy after it solidifies. Polymers produced in this way with non-linear optical properties, in which p, p'-dimethylaminonitrostilbene is used as the host molecule, have been described by Meredith et al., Macromolecules 15 (1982) 1385.

Shibaev et al., Polymer Communications 24 (1983) 364, report the field-induced alignment of liquid crystalline polymers with mesogenic side groups.

U.S. Patent 4,412,059 discloses a polymeric material with cholesteric mesophases accessible by controlled alignment by means of electrical or magnetic fields. Finally, fully aromatic, thermotropic, liquid-crystalline polymers are known from EP-0172012, the nonlinear optical properties of which can also be caused by external fields. Another method for producing polymer materials with non-linear optical properties consists in the polymerization of already ordered monomers which have a non-centrosymmetric orientation, the order state of the system being largely retained during the polymerization. Monomers suitable for this technique can be found, for example, in EP-0021695.

The materials described above still show unsatisfactory non-linear optical properties, which are expressed in particular in poor values for the dielectric susceptibility and the photochemical stability.

There is therefore a need for materials with nonlinear optical properties which do not have the disadvantages described or only to a lesser extent.

This object is achieved by the nonlinear optical materials according to the invention.

The invention therefore relates to nonlinear optical materials, characterized in that they contain at least one component with the structural element of a pyrrolo- [1.2-b] azine of the formula I and / or its valence isomers of the formula I '

included, wherein one of the double bonds shown in dashed lines between positions 2-3, 5-6 and 7-8 can be a single bond, and

R ^{1 is} C ₁ -C ₁₀ alkoxycarbonyl, C ₁ -C ₁₀ alkanoyl, C ₇ -C ₁₁ aroyl, -CN, -CF ₃ , 'N (C _1-4 alkyl) ₂ or H if R is not also H at the same time ,

R ² H or a radical R ¹ ,

R ³ , R ^{3 'is} a radical to complete a dibenzocyclopentadiene, dichlorodibenzocyclopentadiene, monobenzodiphenylcyclopentadiene, tetraphenylcyclopentadiene, dibenzocyclohexa-2,5-diene-4-one ring, or its 4-thione, 4- (C _{1- 4} alkyl) imino or 4-ethylidene derivatives or a dibenzo-ɣ-pyran ring, phenyl, C ₁ -C ₁₀ alkoxycarbonyl, C ₁ -C ₁₀ alkanoyl, indan-1,3-dione-2,2-diyl, 2, 2-dimethyl-1,3-dioxane-4,6-dione-5,5-diyl, 4-nitrophenyl, 4-cyanophenyl, C ₁ -C ₁₀ alkoxypropenoyl, one of the radicals also H,

R ⁴ H, C ₁ -C ₁₀ alkyl or together with R ⁵ a radical to complete a fused-on cyclopentane or cyclohexane ring,

R ⁵ H, C ₁ -C ₁₀ alkyl, C _1-10 alkoxy, C _1-10 alkoxycarbonyl; -CN; -CH ₂ Ph, -COPh, -CONH ₂ , -CON- (C _1-4 alkyl) ₂ , -CONH (C _1-4 alkyl) or together with R ⁴ a radical to complete a fused-on cyclopentane or cyclohexane ring or together with R ⁶ a residue to complete a condensed benzene ring, R ⁶ H, C _1-10 alkyl or together with R ⁵ one

Radical to complete a fused-on benzene ring or together with R ⁷ a radical to complete a fused-on cyclopentane or cyclohexane ring,

H, C _1-10 alkyl or together with R ⁶ a residue to complete a fused cyclopentane or cyclohexane ring and

-N =, -CR ⁴ = or -CHR ⁴ -

mean.

Pyrrolo [1.2-b] azines are known, for example, from DE-Al-29 06 193 and DE-Al-32 20 257. These publications describe the use of the compounds of the formula I as radiation-sensitive materials for measurement, recording and storage purposes.

The compounds of the formula I undergo a conversion into their valence isomers of the formula I 'when irradiated, in particular with short-wave visible light or UV light. Merocyanine-like forms of the formula I 'formed from compounds containing the structural element of the formula I are stabilized both by the negative and by the positive charge by monocyclic aromatic or heteroaromatic ions and / or by suitable electron donor or acceptor substituents. Surprisingly, it has now been found that such compounds are also particularly suitable as components of materials with non-linear optical properties. Layers of monomeric compounds of the formula I and / or I ', polymer compositions with embedded compounds of this type and polymers with chemically bonded structural units of the formula I and / or I' are equally suitable for this purpose.

Particularly suitable are pyrrolo [1.2-b] azines of the formula I and / or I ', in which all dashed bonds mean double bonds. R 1 and R2 are preferably

C ₁ -C ₁₀ alkoxycarbonyl, -CN or -N (C ₁ -C ₁₄ alkyl) ₂ , in particular C ₁ -C ₁₀ alkoxycarbonyl or -CN. R ³ and / or R ^{3 '} preferably mean a substituent which stabilizes a negative charge, such as, for example, C ₁ -C ₁₀ alkoxycarbonyl, phenyl, substituted phenyl, in particular 4-nitrophenyl or 4-cyanophenyl, and also a radical for completing a dibenzocyclopentadiene, dichlorodibenzocyclopentadiene -, Tetraphenylcyclopentadien- or Dibenzocyclohexa-2,5-dien-4-one-ringes, especially a Dibenzocyclopentadiennges. The radicals R ³ and R ^{3 '} can be the same or different, preferably they are the same. R ⁴ preferably represents H, C _1-10 alkyl, in particular C ₁ -C ₄ , and together with R ⁵ a radical to complete a cyclopentane or hexane ring.

R5 is preferably H, C ₁ -C ₁₀ alkyl or C ₁ -C ₁₀ alkoxy -CN, -CH ₂ Ph, -COPh, -CONH ₂ or together with R ⁴ a radical to complete a cyclopentane or hexane ring or together with R ⁶ a residue to complete a benzene ring. R ⁶ preferably denotes H, C ₁ -C ₅ alkyl, together with R ⁵ a radical to complete a benzene ring or together with R ⁷ a radical to complete a cyclohexane ring. R ⁶ preferably denotes H.

R ⁷ preferably denotes H, C ₁ -C ₅ alkyl or together with R ⁶ a radical to complete a cyclohexane ring. Z is in particular -N =, and also -CR ⁴ =.

If appropriate, the alkyl radicals mentioned can also be substituted. Likewise, the aromatic hydrocarbon groups present as a substituent or in condensed form can also carry further substituents. In general, when substitution is mentioned here or below, the following substituents are particularly suitable: C _1-4 alkyl, C _1-4 alkoxy, halogen (fluorine, chlorine, bromine and iodine), -CF ₃ , -NO ₂ , -N (C _1-4 alkyl) ₂ and C _6-10 aryl. However, other substituents can also be used.

Accordingly, according to the invention, those compounds of the general formula I and / or I 'in particular are preferably used as non-linear optical media in which at least one of the radicals R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ or Z has one of the meanings given above.

The compounds of the formula I can be prepared by known processes, as described, for example, in DE-Al-29 06 193 or in DE-A1-32 20 257. A preferred process for their preparation consists in the reaction of cyclopropenes II or pyrazoles III

with the meanings given above for R ¹ , R ² , R ³ and R ^{3 '} with an Azm of the formula IV,

wherein R ⁴ , R ⁵ , R ⁶ , R ⁷ and Z have the meaning given above, in the manner described in DE-A1-35 21 432 under the reaction conditions given there. The production of the required starting materials can also be found in DE-A1-35 21 432.

Components containing the structural element of the merocyanine-like form according to formula I 'are particularly suitable for use in nonlinear optical materials. If an electric field is simultaneously applied from the compounds of the formula I by irradiation with light of a suitable wavelength, the polar structures of the formula I 'obtained are oriented in accordance with the direction of the field and lead to a molecular structure without a symmetry inversion center and thus nonlinear optical properties. The pyrrolo [1.2-b] azines of the formula I and / or I 'are outstandingly suitable as nonlinear optical media. For example, by applying such compounds to a substrate in dissolved or liquid form by, for example, brushing, printing, dipping or spin coating and optionally subsequent irradiation under the action of an electrical field, nonlinear optical arrangements are obtained which, due to their advantageous properties, open up a wide field of application. They are particularly suitable for doubling the frequency of laser light and for producing switching elements, waveguides and phase modulators in the field of integrated optics.

The compounds of the formula I and / or I 'can also develop their nonlinear optical properties in powder form, as inclusions in other molecular groups, such as clathrates, solid solutions, as single crystals or solutions.

The inclusion of compounds of the formula I and / or I 'in polymers is a further subject of the present invention. For this purpose, for example, solutions of suitable polymer materials such as xxi of EP-A2-01 94 639 can be used for the production of waveguides are described, compounds of general formula I are introduced. Doped polymer solutions obtained in this way, as well as corresponding doped polymer melts, can be applied to substrates by the same techniques described above and, if necessary, converted into the valence isomers of the formula I 'by irradiation under the action of an electric field. Another object of the present invention is a non-linear optical polymer material which contains structural units of the general formula I and / or I ', optionally bonded chemically to the polymer chain via connecting groups (spacers).

Such materials contain, for example, recurring structural units of the general formula I and / or I 'in which at least one of the radicals R ¹ , R ² , R ³ , R ^3' , R ⁴ , R ⁵ , R ⁶ , R ⁷ or Z of the formula V corresponds to

-Y-X-A- V

wherein

Y - (CH ₂ ) _n - or -CH (CH ₃ ) -,

X is a chemical bond, -O-, -S-, -NR-, -SO-, -SO ₂ -, -CO-, -O-CO-, -CO-O-, -S-CO-, -CO -S-, -NR'-CO- or -CO-NR'-,

C ₁ -C ₂₀ alkylene, in which one or more non-adjacent CH ₂ groups can also be replaced by -O-, -S- and / or -NR ¹ -,

R 'H or C _1-4 alkyl and

n means 0, 1, 2 or 3.

The binding of the pyrrolo [1.2-b] azine unit to the polymer chain via the residue A can be achieved via a chemical bond or via -CO-O-, -O-CO-, -NR'-CO-, -CO-NR ' -, -NH-CO-O-, -NH-CO-NR'-, -O-CO-NH- or -NR- take place. Particularly suitable spacers are alkylene groups with 2 to 20 carbon atoms, which are linear or branched and in which one or more CH ₂ groups can be replaced by -O-, -S- and / or -NR'-.

For example, the following can be considered as spacers:

Ethylene, propylene, butylene, pentylene, hexylene, octylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, ethylene thioethylene, ethylene-N-methyliminoethylene or 1-methylalkylene.

The spacers can be attached to the pyrrolo [1.2-b] azine moiety and to the polymer chain via a chemical bond or via -CO-O-, -O-CO-, -NR'-CO-, -CO-NR ', -NH- CO-O-, -NH-CO-NR'-, -O-CO-NH- or -NR'-CO-NH- bound.

Y is preferably -CH (CH ₃ ) -, methylene, ethylene or a direct bond. X is preferably -O-, -CO-O-, -O-CO-, -NH-CO-, -CO-NH-, -O-CO-NH or -NH-CO-O-. For A, C ₄ -C ₁₂ alkylene is preferred. R 'is preferably H or methyl.

The polymers which contain pyrrolo [1.2-b] azine units chemically bound can be prepared by processes which are known per se and are customary in polymer chemistry.

For example, in polymeric compounds of the formula VI,

in which T is an interchangeable radical such as hydroxy, chlorine, lower alkoxy, by esterification, transesterification or acylation pyrrolo [1.2-b] azine units with one on a radical R ¹ , R ² , R ³ , R ^{3 '} , R ⁴ , R ⁵ , R ⁶ , R ⁷ or Z terminal hydroxyl, mercapto or amino group are introduced.

The methods are known per se and can be, for example, CM. Paleos et al., J. Polym. Be. Polymer. Chem. Ed. 19 (1981) 1427.

T can also be exchanged with a reactive group of a spacer bound to the pyrrolo [1.2-b] azine unit.

In the case of radicals in which one of the substituents R ¹ , R ² , R ³ , R ^{3 '} , R ⁴ , R ⁵ , R ⁶ , R ⁷ or Z bears a terminal carboxyl group or its functional groups, the polymer must have amino, Contain mercapto or hydroxyl groups.

Such polymers can e.g. by copolymerization of (meth) acrylic acid semiesters of 1, ω-diols with other comonomers.

Another possibility of binding pyrrolo [1.2-b] azine groups to the polymer chain is to react these groups bearing an isocyanate radical with polymers which have substituents which react with isocyanate, for example copolymers bearing hydroxyl groups mentioned above. The isocyanate radical can be converted into a compound of the formula I and / or I ', for example by reacting one of one of the radicals R ¹ , R ² , R ³ , R ^3' , R ⁴ , R ⁵ , R ⁶ , R ⁷ or Z with Isocyanate-reacting substituents such as -OH, -SH or -NH ₂ -bearing pyrrolo [1.2-b] azine, with a diisocyanate in a molar ratio of 1: 1 are introduced.

The reaction of the compounds of the formula I and / or I 'bearing an isocyanate radical with the reactive polymer-carrying polymer is carried out by processes known per se.

Conversely, it is also possible to introduce isocyanate radicals into polymers and to implement the isocyanate radicals with compounds of the formula I and / or I 'which are attached to one of the radicals R ¹ , R ² , R ³ , R ^3' , R ⁴ , R ⁵ , R ⁶ , R ⁷ or Z carry a terminal substituent which reacts with isocyanate.

Polymers bearing pyrrolo [1.2-b] azines bonded in the side chain or attached to the side chain can also be prepared by, for example, synthesizing pyridazyl compounds in the 4-position with a polymerizable radical, preferably an acrylate, and then first homo- or copolymerized. The pyrroloazine skeleton is then built up by reaction with a cyclopropene II.

The polymers can also be obtained by copolymerizing ethylenically unsaturated compounds of the formula (VII)

optionally with other olefinically unsaturated compounds which can be copolymerized with (VII). In the formula (VII), W represents a pyrrolo [1.2-b] azine of the formula I and / or I 'which is optionally bonded to the carbon atom of the carbonyl radical via a spacer, the bond being via -O-, -S- or -NR- 'takes place.

The degree of polymerization is generally between 5 and 500, preferably between ≧ 10 and 100.

The following are particularly suitable as monomers:

C ₁ to C ₂₀ , preferably C ₄ to C ₈ alkyl esters of acrylic acid and / or methacrylic acid, mixtures of these esters and mixtures of the esters mentioned with acrylonitrile, methylacrylonitrile, styrene, 4-methylstyrene, acrylic and / or methacrylamide .

As monomers, in addition to the specific ones mentioned, e.g. considered:

Methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, nonylacrylate, decyl acrylate, dodecyl acrylate, hexadecyl acrylate, octadecyl acrylate and the corresponding methacrylate.

The above-mentioned acrylates and methacrylates of alkanols having up to 8 carbon atoms are preferred.

The polymers are prepared by known processes, preferably by radical polymerization.

They can also be obtained by adding polarizable, reactive hydrogen-bearing radicals to olefinic double bonds. For example, poly-organo-hydrogen siloxanes can be reacted with compounds of the formula I and / or I 'containing a terminal vinyl group, if appropriate in solvents in the presence of catalysts, in particular hexachloroplatinic acid, which accelerate the addition of hydrogen bonded to Si to aliphatic multiple bonds .

These reactions are carried out in a manner known per se (H. Ringsdorf, A. Schneller; Brit. Polym. Journal 13, 43 (1981); H. Ringsdorf, A. Schneller; Makromol. Rapid Comm. Vol. 3, 557 (1982) ).

The polymer materials according to the invention open up a wide field of application on account of their advantageous non-linear optical properties. They are particularly suitable for doubling the frequency of laser light and for producing switching elements, waveguides and phase modulators in the field of integrated optics.

The following examples serve to explain the invention:

A. Preparation of the connections

a) Preparation of spiro-3H-pyrazoles III

2 g of the diazofluorene derivatives are dissolved in anhydrous ether and equimolar amounts of the corresponding alkyne esters are added dropwise with stirring. The reaction mixture is stirred in a darkened vessel at room temperature and the course of the reaction is checked by means of thin layer chromatography (TLC). After the reaction is complete, the solvent is removed under reduced pressure. The residue is recrystallized.

b) Preparation of spirocyclopropenes II

2 g of the Spiro-3H-pyrazole III are dissolved in 300 ml of anhydrous ether and irradiated in a photolysis apparatus at room temperature until the TLC control and the amount of nitrogen developed indicate that the reaction is complete. After concentrating the solution under reduced pressure, the crystals form in the cold.

c) Preparation of pyrroloazines I by nucleophilic addition of the heterocycles IV to the spirocyclopropenes II.

1 mmol of the spirocyclopropenes II are reacted in dry ether with 1-2 mol equivalents of the heterocycles IV. A coloration of the reaction solution indicates the formation of betaines. Further stirring at room temperature with exclusion of light leads, with brightening, to the formation of the pyrrolo (l, 2-b) azines I which, after chromatographic workup (silica gel / CH ₂ Cl ₂ ), are obtained in pure form by recrystallization.

1 'H-pyrrolo [1.2-b] pyridazines la from the compounds II and III

la

No. R ¹ / R ² R ⁶ R ⁷ R ⁸ R ⁹ R ¹⁰ R ¹¹ R ¹² R ¹³ Smp

[° C] from 1 CO ₂ C ₃ H ₇ HHHHHHHHHH 120 II 2 CO ₂ C ₄ H ₉ HHHHHHHHHH 97 II 3 CO ₂ C ₅ H ₁₁ HHHHHHHHHH 80 II

4 CO ₂ C ₆ H ₁₃ HHHHHHHHHH 69 II

5 CO ₂ C ₇ H ₁₅ HHHHHHHHHH 51 II

r. R ¹ / R ² R ⁴ R ⁵ R ⁶ R ⁷ R ⁸ R ⁹ R ¹⁰ R ¹¹ R ¹² R ¹³ Smp

[° C]

CO ₂ C ₃ H ₇ CH ₃ HH CH ₃ HHHHHH 153 II

C0 ₂ C ₄ H ₉ CH ₃ HH CH ₃ HHHHHH 117 II

8 CO ₂ C5H ₁₁ CH ₃ HH CH ₃ HHHHHH 98 II

9 CO ₂ C ₆ H ₁₃ CH ₃ HH CH ₃ HHHHHH 82 II

10 CO ₂ C ₇ H ₁₅ CH ₃ HH CH ₃ HHHHHH 74 II

11 CO ₂ C ₅ H ₁₁ CH ₃ CH ₃ H CH ₃ HHHHHH 108 II

12 CO ₂ C ₅ H ₁₁ CH ₃ CH ₃ CH ₃ CH ₃ HHHHHH 146 II

13 CO ₂ C ₅ H ₁₁ H - Benzo - HHHHHHH 68 II

14 CO ₂ C ₄ H ₉ H CH ₃ HHHHHHHH 89 II

15 CO ₂ C ₅ H _{1 1} H CH ₃ HHHHHHHH 73 II

No. R ¹ / R ² R ⁴ R ⁵ R ⁶ R ⁷ R ⁸ R ⁹ R ¹⁰ R ¹¹ R ¹² R ¹³ Smp

[° C]

16 CO ₂ CH ₃ CH ₃ CO ₂ CH ₃ H CH ₃ HHHHHH 194 II

17 CO ₂ CH ₃ H CN HHHHHHHH 82 II

18 CO ₂ CH ₃ H CH ₂ Ph HHHHHHHH 140 II

19 CO ₂ CH ₃ H COPh HHFHHHFH II

20 CO ₂ CH ₃ H CONH ₂ HHHHHHHH 117 II

21 CO ₂ CH ₃ HHHHH CO ₂ CH ₃ HHH 179 II

22 CO ₂ CH ₃ H CO ₂ CH ₃ HHHHHHHH 106 II

23 CO ₂ CH ₃ H CO ₂ CH ₃ HHH CO ₂ CH ₃ HHH 159 II

24 CO ₂ CH ₃ - (CH ₂ ) ₃ - CH ₃ CH ₃ HHHHHH 200 II

25 CO ₂ CH ₃ - (CH ₂ ) ₄ - CH ₃ CH ₃ HHHHHH 158 II

[° C]

26 CO ₂ CH ₃ (CH ₂ ) 4- - (CH ₂ ) ₄ - HHHHHH 166 II

27 CN H CO ₂ C ₅ H ₁₁ HHHHHHHH 127 III

28 CO ₂ CH ₃ HHHHHH CO ₂ C ₂ H ₅ HHH 176 II

29 CO ₂ C ₇ H ₁₅ CH ₃ C ₄ H ₉ H CH ₃ HHHHHH 52 II

30 CO ₂ C ₆ H ₁₁ HHHHHHHHHH 72 II

31 CP ₂ C ₆ H ₁₁ CH ₃ HH CH ₃ HHHHHH 58 II

32 CO ₂ C ₆ H ₁₁ H - Benzo - HHHHHHH 58 II

33 CO ₂ CH ₃ HHHH - Benzo - H - Benzo - H

34 CO ₂ CH ₃ HHHH - Benzo - HH - Benzo -

B. Use of the compounds

example 1

A concentrated solution of 6 ', 7'-dicyano-spiro- [9H-fluorene-9,5' (4'aH) -pyrrolo [1, is placed on a glass plate provided with vapor-deposited interdigital electrodes (distance between the electrodes 1 mm). 2-b] pyridazine] -3'-carboxylic acid pentyl ester (prepared according to DE-A1-35 21 432) in toluene. An electrical field of 1.5 kV / mm is applied to the electrodes and simultaneously irradiated with UV light. After the solvent has evaporated with an applied electric field, a thin layer of the red betaine compound remains, which has second-order nonlinear optical properties. In the case of oblique transversal radiation with light from an NdYAG laser, this layer partially doubles the frequency of the incident light.

Example 2

A solution of polymethyl methacrylate PMMA (40% by weight) and 6 ', 7'-dicyano-spiro [9H-fluorene-9,5' (4'aH) -pyrrolo- [1,2-b] pyridazine] -3 ' -carboxylic acid pentyl ester (2% by weight) in toluene is applied by spin coating to a glass plate provided with interdigital electrodes according to Example 1. The toluene is allowed to evaporate at room temperature. The polymer film obtained is heated to 105 ° C and it becomes an electric field of

1.5 kV / mm applied, with simultaneous irradiation with UV light. After 5 minutes, the mixture is cooled to room temperature in the E field. What remains is a transparent, red polymer film with non-linear optical properties of the second order. Example 3

A solution of 6 ', 7'-dicyano-spiro [9H-fluorene-9,5'- (4' aH) -pyrrolo [1,2-b) pyridazine] -3'-carboxylic acid pentyl ester (1%) and of poly -4- (4'-cyanbiphenyl (4) -oxycarbonyl) -phenoxyethyl methacrylate (20%) in N-methylpyrrolidone is applied by spin coating to a glass plate provided with interdigital electrodes. The N-methylpyrrolidone is allowed to evaporate at elevated temperature. The polymer film is heated to 150 ° C and otherwise treated as in the previous example. A transparent, red, oriented liquid-crystalline polymer film with non-linear optical properties of the second order is obtained.

Example 4

A mixture of 2.17 g of 6 ', 7'-dicyano-spiro [9H-fluorene-9,5'(4'aH) pyrrolo [1,2-b] pyridazine] -3'-carboxylic acid pentyl ester, 2.0 g of 1,10-decanediol and 0.75 ml of titanium tetra-isopropanolate are heated to 80 ° C. and the resulting solution is kept at this temperature for 7 hours. The reaction mixture is cooled to approx. 40 ° C., 1N HCl is added and the mixture is extracted with dichloromethane. The organic phase is dried over Na ₂ SO ₄ and evaporated. The residue is chromatographed on a silica gel column, whereupon yellow crystals of 6 ', 7'-dicyano-spiro [9H-fluorene-9,5'(4'aH) pyrrolo [1,2-b] pyridazine] -3'- carboxylic acid (10-hydroxydecyl ester) can be obtained. Example 5

To a solution of 2.08 g of 6 ', 7'-dicyano-spiro [9H-fluorene-9,5' (4'aH) pyrrolo [1,2-b] pyridazine] -3 'kept at 0 ° C carboxylic acid (10-hydroxydecyl ester), 344 mg methacrylic acid, 49 mg 4-dimethylaminopyridine and 1 mg

2,6-di-tert-butyl-4-methylphenol in 10 ml dichloromethane, a solution of 929 mg dicyclohexylcarbodiimide in 1 ml dichloromethane is added dropwise and the mixture is stirred at RT for 2 h. The precipitate is filtered off, the filtrate is concentrated and the residue is chromatographed. It becomes 6 ', 7'-

Dicyano-spiro [9H-fluorene-9, 5 '(4'aH) pyrrolo [1,2-b] pyridazine] -3'-carboxylic acid (10-methacryloyloxydecyl ester) was obtained as yellow crystals.

Example 6

A solution of 294 mg of 6 ', 7'-dicyano-spiro [9H-fluorene-9,5'(4'aH) -pyrrolo [1,2-b] pyridazine] -3'-carboxylic acid (10-methacryloyloxydecyl ester) , 951 mg of methyl methacrylate and 50 mg of azobisisobutyronitrile in 20 ml of toluene is heated to 60 ° C. under N _{2 for} 20 h. The polymer is reprecipitated twice from ethanol, giving a yellowish color

Polymer. A film with nonlinear optical properties is produced from this polymer analogously to Example 2.

Example 7

A solution of 294 mg of 6 ', 7'-dicyano-spiro [9H-fluorene-9,5'(4'aH) -pyrrolo [1,2-b] pyridazine] -3'-carboxylic acid (10-methacryloyloxydecyl ester) , 4.06 g of 4- (4'-cyanobiphenyl- (4) -oxycarbonyl) -phenoxyethyl methacrylate and 50 mg Azobisisobutyronitrile in 30 ml of N-methylpyrrolidone is heated to 60 ° C. under N _{2 for} 20 h. The polymer is reprecipitated twice from ethanol. A yellowish polymer is obtained. An oriented liquid-crystalline polymer film with nonlinear optical properties is obtained from this polymer analogously to Example 3.

Example 8

A solution of 1 g of 3- (4-pyridazyl) acrylic methacrylate and 0.9 g of dibenzoyl peroxide in 19 g of methyl methacrylate (molar ratio of the esters 1:31) is left to stand at 60 ° C. for 29 hours. Then it is dissolved in dichloromethane and reprecipitated from methanol. Poly (methyl-3-pyridazin-4'-yl) acrylate-co-methyl methacrylate is obtained as a pale yellow polymer.

Example 9

A solution of 4.6 g of the copolymer from Example 8 in 20 ml of dichloromethane is mixed with 0.5 g of 1,2-dimethoxycarbonyl-spiro [cyclopropene-3,9'-fluorene] and the resulting solution for 48 hours with the exclusion of light touched. Poly (methyl-3-6 ', 7'-dicarboxymethyl-spiro [9H-fluoren-9,5' (4'aH) -pyrrolo [1.2-b] -pyridazin] 3'-yl) acrylate-co- methyl methacrylate as a yellow polymer.

Claims

1. Nonlinear optical materials, characterized in that they have at least one component with the structural element of a pyrrolo [1.2-b] azine of the formula I and / or its valence isomers of the formula I '

C ₁ -C ₁₀ alkoxycarbonyl, C ₁ -C ₁₀ alkanoyl, C ₇ -C ₁₁ aroyl, -CN, -CF ₃ , -N (C _1-4 alkyl) ₂ or H, if R ^{2 is} not simultaneously H,

H or a radical R ¹ , R ³ , R ^{3 '} a residue to complete one

Dibenzocyclopentadiene, dichlorodibenzocyclopentadiene, monobenzodiphenylcyclopentadiene, tetraphenylcyclopentadiene, dibenzocyclohexa-2,5-dien-4-one ring, or its 4-thione, 4- (C _1-4 -

Alkyl) imino or 4-ethylidene derivatives or a dibenzo-γ-pyran ring, phenyl,

C ₁ -C ₁₀ alkoxycarbonyl, C ₁ -C ₁₀ alkanoyl, indan-1,3-dione-2,2-diyl, 2,2-dimethyl-1,3-dioxane-4,6-dione-5,5- diyl, 4-nitrophenyl-, 4-cyanophenyl, C ₁ -C ₁₀ alkoxypropenoyl, one of the radicals also H,

R ⁵ H, C ₁ -C ₁₀ alkyl, C _1-10 alkoxy, C _1-10 alkoxycarbonyl; -CN; -CH ₂ Ph, -COPh, -CONH ₂ , -CON (C _1-4 alkyl) ₂ , -CONH (C _1-4 -

Alkyl) or together with R ⁴ a residue to complete a fused-on cyclopentane or cyclohexane ring or together with R ⁶ a residue to complete a fused-on ring

Benzene ring,

R ⁶ H, C _1-10 alkyl or together with R ⁵ one

Radical to complete a fused-on benzene ring or together with R ⁷ a radical to complete a fused-on cyclopentane or cyclohexane ring, R ⁷ H, C _1-10 alkyl or together with R ⁶ one

The rest to complete a fused cyclopentane or cyclohexane ring and

-N =, -CR ⁴ = or -CHR ⁴ -

mean.

2. Nonlinear optical material according to claim 1, characterized in that it consists essentially of a layer applied to a substrate of at least one compound of formula I.

3. Nonlinear optical material according to claim 1, consisting of at least one polymeric component, characterized in that at least one further component is a compound of general formula I.

4. Nonlinear optical material according to claim 1, consisting of at least one polymeric component, characterized in that the structural element of pyrrolo [1.2-b] azine according to formula I is optionally chemically bound to the polymer chain via a spacer.

5. A method for producing the nonlinear optical materials according to claims 1-4, characterized in that one component is irradiated with the structural element of the formula I with simultaneous application of an electric field.

6. Use of the nonlinear optical materials according to claims 1 to 4 as optical media in electronics or as organic substrates in fiber and film technology.