DE4244505A1 - New tetra:hydro:naphthalenone derivs. used in polymer contg. chromophore - Google Patents

Abstract

New 7-substd.-4,4a,5,6-tetrahydro-2-(3H)-naphthalenone derivs. are of the formula (D)n-X. New polymers (II) contain at least 10 wt.% E gps. of the formula -X-(CH2)x-Y-X (where X = a gp. of formula (III). A and A1 = NO2, CN, halogen, CF3, COOR5, CONR62 or SO2R7; or one of A and A1 = H, -COO(CH2)x, ZH, SO3R5, SOR7, SO2NR62 or S(NSO2CF3)CF3; x = 2, 3, 4 or 5; Z = O, S or NH; R1-4 and R6 = H or 1-4C alkyl; R5 = 1-4C alkyl; R7 = 1-4C alkyl, 1-4C perfluoroalkyl or (substd.) phenyl; R8 = 1-22C alkyl, opt. with a terminal OH, SH or prim. or sec. amino substit., or H(OCH2CH2)m; Q = an (n+1)-valent gp. derived from an aromatic carbocyclic or heterocyclic ring system with up to 3 rings; p = 0 or 1; n = 1, 2 or 3; m = 1, 2, 3, 4, 5 or 6).

Description

The invention relates to derivatives of 4, 4a, 5, 6-tetrahydro-2- (3H) -naphthalenone, which in 7-position contain an electron donor group and its keto group by an olefinic double bond is replaced, which has at least one electron acceptor Group carries. The invention further relates to layer elements that these connections contained in the form of layers on a support and the use of the Connections for non-linear optics purposes.

Because of the different substituents, the molecules are named Non-centrosymmetric connections. Therefore, they usually become a dipole moment exhibit. They also have an extensive π electron system with several Chromophores. All of this makes them suitable for purposes of nonlinear optics.

The non-linear optics (NLO) allows u. a. with the help of suitable devices two light beams of different frequencies to get a new frequency that corresponds to the difference or the sum as well as one from a light beam optical frequency optical signals with a multiple (especially the To get double) of this frequency. The nonlinear optics also allows that Conversion of electrical information into optical information and therefore leads possibly a fundamental change in the technology of Data transmission and data storage.

NLO materials are suitable for the production of non-linear optical Components, for example electro-optical modulators, electro-optical Switches, electro-optical directional couplers and frequency doublers. This Components are used for. B. in optical communications ( Modulation and control of optical signals), as spatial light modulators  in optical signal processing, for frequency doubling of semiconductor lasers, for optical data storage, sensor technology and xerography.

The main goal is the production of electro-optical or purely optical Devices with a low voltage and with the available ones Luminous intensity of a semiconductor laser can be operated. These requirements are only met by materials that have large electro-optical coefficients (in particular Bockel's coefficient = r and y) and (due to their Processability) suitable for the production of efficient waveguide systems are.

A whole series of inorganic crystals, such as e.g. B. Potassium dihydrogen phosphate and lithium niobate examined. Modulators Lithium niobate and frequency doubler based on potassium dihydrogen phosphate are commercially available.

In addition, organic NLO materials are of great interest. this has several reasons. On the one hand, the NLO activity (= NLO susceptibility) is more organic Materials are often much higher than inorganic materials. The refractive index and the dielectric constant are generally lower. this makes possible larger internal electric fields, smaller polarizations and fewer Reflection losses, which all leads to higher efficiency.

Furthermore, organic materials can be synthesized "tailor-made", e.g. B. with the aim of providing materials with a high degree of transparency for a particular Get working wavelength. Organic materials can be used in many different ways Process wise men. The production of monomolecular films from organic Materials is easier than e.g. B. the production of inorganic crystals. This Crystals have to be grown at higher temperatures, then cut, polished and be oriented. There is therefore a need for organic materials for Applications in the field of 2nd order non-linear optics.  

The (macroscopic) polarization P caused by an electrical medium Field is induced in a power series of the electric field strength E be developed.

P = X ⁽¹⁾ E + X ⁽²⁾ E ² + X ⁽³⁾ E ³ +. . .

The X ⁽ⁱ⁾ are the so-called electrical susceptibility functions. The susceptibilities X ⁽²⁾ and X ⁽³⁾ depend on the so-called molecular hyperpolarizabilities β and γ.

X ⁽²⁾ (-ω3, ω2, ω1) _XYZ = Nf _{X, ω3} f _{Y, ω2} f _{Z, ω1} D _XYZxyz β _xyz
P₁ = αE + βE² + γE³ +. . .

P _{1 is} the polarization of the molecule; α, β and γ are polarizabilities. N is the number of molecules per unit volume, f is the local field factor and D _{XYZxyz is} a tensor that describes the orientation of the molecules in the macroscopic system.

NLO interactions can create new frequencies in an NLO medium generated and the refractive index of the medium can be changed.

Important nonlinear optical effects that depend on X ⁽²⁾ are the frequency doubling of a laser beam, the parametric amplification of a weak light signal and the electro-optical conversion of electrical signals. In order to achieve 2nd order effects, the active molecules must be aligned non-centrosymmetrically, since X ⁽²⁾ = 0 for centrosymmetric molecules or crystals.

One can try to grow crystals of the NLO compound. If these crystallize non-centrosymmetrically, the crystal (without further treatment) has a non-vanishing second-order macroscopic susceptibility X ⁽²⁾ . A very high concentration of the chromophore and a very high order are achieved with crystals, and furthermore there are no problems with the relaxation of the order, since the non-centrosymmetric order represents the state of lowest free energy. However, the processability of many crystals is poor and the manufacture of integrated optical components with single crystals is usually impractical. Furthermore, non-centrosymmetric molecules can also lead to centrosymmetric crystals.

The method of producing thin layers according to J. Langmuir and K. B. Blodgett (= LB process) probably offers the greatest freedom in chemical Planning, but requires extensive experience. In this procedure Molecules spread on a water surface by reducing the area arranged in parallel per molecule, and with constant thrust by immersion and Removing a carrier mounted on a substrate. Per dive transfer a monomolecular layer while maintaining its order. For the The construction of LB layers uses amphiphilic molecules, i. H. Molecules that have a hydrophilic (a "head") and a hydrophobic end (a "tail").

To enable LB layers with high 2nd order susceptibilities, one makes organic compounds that have both high molecular hyperpolarizabilities 2nd order β and amphiphilic properties.

If one looks at amphiphilic material that consists of a single type of molecule arranging the LB process into multilayers can do three different ones Possibilities of diving behavior occur: There can be films of the X type (Transmission only during immersion) or Z type (transmission only during removal), both of which do not take advantage of have a centrosymmetric structure. Mostly, however, films of the Y type appear (Transfer during immersion and removal) in which the molecules have a Show head-head and tail-tail arrangement.

In most cases, Y-type films have a centrosymmetric structure. At the few connections that have an orientation in the carrier plane (ie have a non-centrosymmetric structure) is the attainable  Susceptibility relatively low. To deal with connections leading to films of the Y type lead to a multilayer arrangement with a non-centrosymmetric structure three strategies can be used:

• a) A film is formed with active layers and inactive layers (amphiphilic molecules without chromophore or polymers without chromophore, e.g. Alternate trimethylsilyl cellulose or polymethacrylic acid ester). This method has the disadvantage that the NLO-active molecules do not have the available volume Make efficient use of the system because the inactive layers "dilute" the system to lead. Therefore, such films show less NLO activity.
• b) You control the transfer process so that you get Z-type films. To are special multi-chamber systems for coating the substrates required. Immersion and immersion take place in different chambers.
• c) You alternately transfer films from 2 different NLO-active Amphiphiles, the dipole moments of which form the hydrophobic long-chain alkyl Rest (tail) directed and once turned away from him. In this case the dipole moments of two neighboring layers will differ despite the Don't cancel the Y-structure, add it. The effective dipole moment is therefore still on a scale that makes it interesting for NLO purposes.

Another method of aligning the chromophores in materials with non- Centrosymmetric structure consists in the installation of an NLO-active Chromophors in a polymer matrix ("poled polymer"). You can e.g. Legs Dissolve low molecular weight NLO-active compound directly in a polymer. Through a strong electric field, the chromophores can be partially aligned. After that, however, there is a rapid relaxation of the order, so that with this method only requires a relatively low alignment of the chromophores to achieve. Another disadvantage is the limited solubility of the low molecular weight NLO active compounds in the polymer.  

The stability of the order and the concentration of chromophore groups can be further increased if they are covalently integrated into the polymer, for example as a side chain or parts of a polymer main chain. By increasing the glass temperature or subsequent crosslinking can change the orientation be largely stabilized.

It is always desirable for the NLO-active connection to be as large as possible optical non-linearity β (= second order hyperpolarizability). A Compound has a great value for β if it is a conjugated π- Contains electron system (e.g. the stilbene residue) and at least one Electron donor and at least one electron acceptor group is present. The value for β is increased if the molecule has light in the wavelength range of the incident electric field or the field generated by NLO absorbed (so-called resonance amplification). However, absorptions are for many applications undesirable because they cause losses and the optical Negatively affect stability. A connection is considered "optically stable" if the Light intensity can be endured for a long time without being permanent Material damage comes. An ideal connection would have a great one Hyperpolarizability β, but no residual absorption in the desired Wavelength range. However, most connections show one sufficiently high value for β still considerable residual absorption in the desired wavelengths for frequency doubling, especially in the range of 415 nm, which by frequency doubling of IR light of the frequency 830 nm (Diode laser).

Since compounds with large dipole moments and at the same time high values for β are of interest, NLO-active compounds have already been investigated, the Chromophore consists of a conjugated π system, the ends of which with a Electron acceptor and an electron donor are provided. Known Connections are e.g. B. 4-dimethylamino-4'-nitrostilbene (DANS) and 2-methyl-4- Nitroaniline (MNA). From European patent applications EP 0 364 313 and 0 390 655 NLO-active compounds are known which differ from one  Derive cyclohexenone and contain 3 or 4 conjugated double bonds. The preferred electron acceptor is the cyano radical and is more preferred The electron donor is the p-dimethylaminophenyl group. The product µ × β is only 1.9 times larger than in DANS.

However, the NLO properties of the disclosed compounds are not yet sufficient to e.g. B. Poled polymers with a satisfactory electro-optical To achieve coefficients (r <60 pm).

The task was therefore to create new organic NLO-active compounds to provide that have even higher values for the product µ × β. Another Task relates to the provision of connections in devices for Frequency doubling or can be used to modulate light.

The invention relates to compounds of general formula I.

wherein

R ¹ and R ² independently of one another are H or C ₁ -C ₄ alkyl,
R ³ and R ^{4 are} C ₁ -C ₄ alkyl or hydrogen,
A and A ¹ independently of one another NO ₂ , CN, halogen, CF ₃ , COOR ⁵ , CONR ₂ ⁶ SO ₂ R ⁷ , or
one of the radicals A and A ^{1 is} also hydrogen, -CO ₂ (CH ₂ ) _x ZH, SO ₃ R ⁵ , SOR ⁷ , SO ₂ NR ₂ ⁶ or S (NSO ₂ CF ₃ ) CF ₃ ,
x 2, 3, 4 or 5,
ZO, S or NH,
R ⁵ C ₁ -C ₄ alkyl,
R ⁶ C ₁ -C ₄ alkyl or hydrogen,
R ⁷ C ₁ -C ₄ alkyl or C ₁ -C ₄ perfluoroalkyl or an optionally substituted phenyl radical,
D NR ₂ ⁸ , OR ⁸ , SR ⁸ ,
R ^{8 is} C ₁ -C ₂₂ alkyl, which can also be substituted by a terminal hydroxyl, thiol or primary or secondary amino group, or the group H (OCH ₂ CH ₂ ) _m ,
Q is an (n + 1) -valent radical which is derived from an aromatic carbocyclic or heterocyclic ring system with up to three rings,
p 0 or 1,
n 1, 2 or 3 and
m 1, 2, 3, 4, 5 or 6

means.

The residues D act as an electron donor and at least one of the residues A and A ¹ acts as an electron acceptor. If one of the radicals A and A ^{1 represents} the group CO ₂ (CH ₂ ) _x ZH, the radical R ⁸ is preferably a C ₁ -C ₂₂ alkyl radical.

The rest Q acts as a bridge for π electrons. Examples of carbocyclic Ring systems are benzene, naphthalene, anthracene. Examples of a heterocyclic Ring system from which the rest Q is derived are pyrrole, furan, thiophene, Imidazole, pyrazole, oxazole, thiazole, pyridine, pyrimidine, triazine, quinoline, isoquinoline, Quinoxaline, indole, benzimidazole and benzothiazole.

The radical Q can carry 1, 2 or 3 radicals D, for example three methoxy radicals. D is preferably the dimethylamino, methoxy or methylthio group.

Q is preferably derived from benzene or thiophene. In both cases it is preferred
D for HZ- (CH ₂ ) _x -Y-
Z for O, NR ⁹ , S
x for a number from 1 to 18
Y for O, S, NR ¹⁰ and
R ⁹ , R ¹⁰ independently of one another for C ₁ -C ₄ alkyl or hydrogen.

These compounds are not only NLO-active, but they also have a functional group HZ- with the possibility of reaction with other low-molecular or high-molecular compounds which are themselves NLO-inactive. Reactive compounds in which Z is oxygen and Y is oxygen or NCH ₃ are particularly preferred.

Compounds of the general formula I in which D is NR ⁸ R ¹⁰ , OR ⁸ or SR ⁸ , R ^{10 is} C ₁ -C ₄ -alkyl or H and R ^{8 is} C ₁₆ -C ₂₂ -alkyl contain a long-chain alkyl group and at least one polar group A or A ¹ . They therefore behave amphiphilically and can be arranged on supports by the Langmuir-Blodgett method in the form of monomolecular layers or multilayers.

The invention therefore also relates to a layer element which has at least one contains a monomolecular layer consisting of a compound of formula I. The layer elements preferably contain at least two monomolecular elements Layers of the amphiphilic compounds according to the invention on a support. For purposes of nonlinear optics, it is advantageous if the layer thickness is at least 0.1 microns because z. B. conventional optical fiber with very thin Layer thicknesses are not possible. The thickness of a single monolayer is in the order of magnitude at 3 nm.

For the production of layer elements according to the invention with Langmuir-Blodgett The amphiphilic compounds are filmed in a highly volatile film Bring solvent to a clean water surface (spread). From the Dimension of the surface, the spreading volume and the concentration of the solution the average area per molecule can be calculated. Phase transitions at Compression of the molecules can be followed in the shear surface isotherm.  

The molecules are protected with a barrier or by other techniques, e.g. B. Using hydrodynamic forces, pushed together, the chains at increasing density can be oriented essentially perpendicular to the boundary layer. During the compression, self-assembly of the molecules in the Boundary layer is a highly ordered, monomolecular film whose constant Layer thickness is determined by the chain length of the molecules. The typical thickness such a film is between 2 and 3 nm.

The invention further relates to a polymer in which in the main chain or in the Side chains containing the tetrahydro-naphthalene residue. The polymer can be spin onto a carrier as a thin layer. You can then in heat the proximity of the glass temperature of the polymer and at that temperature create a strong voltage field (approx. 150 V / µm) through which the polar Chromophores are at least partially aligned. With slow cooling the layer while maintaining the tension manages the orientation of the Freeze chromophores to a large extent. Due to the covalent bond of the NLO active chromophores in the poled polymers will change the order of the Chromophores stabilized and the introduction of a relatively high proportion Allows chromophores in the polymer.

The polymers according to the invention preferably contain at least 10% by weight. the rest E

where R ¹ , R ² , R ³ , R ⁴ , A and A ^{1 have} the meaning given for formula I,
Z for O, NR ⁹ or S,
x for a number from 1 to 18,
Y stands for O, S, NR ¹⁰ and
R ⁹ and R ¹⁰ independently of one another are C ₁ -C ₄ alkyl or hydrogen.

The main chain of the polymer according to the invention is preferably derived from polyacrylic acid and the side chains contain the remainder E. To produce the polymers, an activated derivative, such as, for example, an acid chloride of polyacid, can be reacted with a reactive compound of the general formula I in which D represents HZ- (CH ₂ ) _x -Y- or A represents CO ₂ (CH ₂ ) _x ZH (where x and Z have the meaning given in formula I). It is also possible to polymerize a low molecular weight acrylic acid derivative which contains the radical E, optionally in the presence of other monomers. However, depending on the nature of the substituents present, the polymerization can be difficult. Particularly suitable comonomers are alkyl esters of methacrylic acid and acrylic acid.

This method can be used to make homopolymers or copolymers produce general formula II

in which
R ¹¹ and R ¹³ independently of one another for H, CH ₃ , Cl, F or CF ₃
G for CO ₂ R ¹² , CONHR ¹² , CONR ₂ ¹² or -CN
R ^{12 represents} H or C ₁ -C ₁₀ alkyl and
E has the meaning given above.

By reaction of compounds of the formula I in which D is a bis (ω- hydroxyalkyl) amino residue, with an arylene or alkylene diisocyanate Polyurethane with the structural unit

By applying the materials according to the invention to a substrate in solution or liquid form by, for example, painting, printing, dipping or Spin-on nonlinear optical arrangements are obtained when the Materials have amphiphilic properties or strong interaction (Physisorption, chemisorption) with the substrate surface. The Compounds of the formula I can also be used as single crystals or as Crystal powder, incorporated in clathrates or dissolved in polymers, their NLO Make use of properties.

The materials according to the invention can according to standard methods of organic chemistry.

The reaction conditions can be the standard works of the preparative are taken from organic chemistry, e.g. B. Houben-Weyl, Methods of Organic Chemistry, Georg Thieme Verlag, Stuttgart.

Said compounds, in which A = A ¹ = -CN, can be prepared by condensing dimethyl tetrahydronaphthalenone (US Pat. No. 3,217,717) with malodinitrile and an aldehyde R-CHO in a manner known per se. The reaction proceeds according to the following equation:

Ketones give an analogous implementation. The condensation is advantageous with the addition of a dehydrating agent such as acetic anhydride, a base such as ethylamine, piperidine, pyridine or a salt such as ammonium acetate or piperidinium acetate in a solvent such as dimethylformamide. To determine the completion of the reaction and improve the yields, the addition of an inert solvent such as. B. toluene in connection with heating on the water separator as advantageous.

If the radicals R ¹ and R ^{2 are} both alkyl radicals, compounds of the general formula III in which the radicals R ¹ and R ^{2 are} on the same carbon atom are preferred for reasons of ease of preparation

Compounds in which R ¹ and R ^{2 are} hydrogen are also easily accessible.

Compounds in which Q is a phenylene radical and p = 1, that is to say two conjugated Having vinyl groups outside the ring system can be produced by Condensation of the corresponding substituted cinnamaldehyde (e.g. p-dimethylamino-cinnamaldehyde) with a 4,4,7-trimethyl-tetrahydronaphthalene Derivative. Connections in which p = 0 can be established if one starts from a compound that has an aldehyde group attached to the cyclic System Q contains.

Solid bodies with clean surfaces are suitable as supports, for example Glass, ceramic or metal plates, plastic layers made of PMMA, for example, Polystyrene, polycarbonate, polyethylene, polypropylene or polytetrafluoroethylene, or Metal layers on the substrates mentioned.  

To experimentally determine the value of 2nd order susceptibility (X ⁽²⁾ ) in Langmuir-Blodgett films, one can use the phenomenon of optical frequency doubling, in which in an active substance a laser beam with frequency ω is converted into a beam with frequency 2ω is converted. The intensity of the harmonic generated at 2ω increases quadratically with the incident intensity of the fundamental beam at ω. The so-called "maker fringes" method is used most frequently and is briefly described here.

The source of the electromagnetic wave at the angular frequency is ω typically uses a Nd: YAG laser that uses a short (typically 30 ps- 30 ns) light pulse generated. The light pulse is divided into two by a beam splitter Beams divided into a sample channel and a reference channel. In the test channel the layer system to be measured is mounted on a turntable. A small part of the incident beam is converted into a beam by the NLO active system doubled frequency converted. The intensity of the harmonic wave will measured by a photomultiplier, by data acquisition electronics and a control computer recorded as a function of the angle of incidence and over several Shots averaged per angle. Polarization elements and filters ensure that only the harmonic wave generated in the sample at controlled Polarization conditions is measured.

An NLO-active substance, e.g. B. powdered 2- Methyl 4-nitroaniline, assembled; it is used by fluctuations in energy and the temporal and spatial beam profiles caused scattering of the equalize measured intensity. Then a calibrated sample measured, e.g. B. a quartz crystal, the susceptibility about 1 pm / V is. From the angular dependence of the harmonic intensity and its value compared to the intensity of the calibrated sample, the NLO susceptibility as well Information on the alignment of the chromophores can be obtained.

The NLO activity of a crystal, in particular consisting of one compound according to the invention can by the so-called Kurtz powder process  to be examined. The compound to be examined is in a mortar crushed and in an approx. 0.2 mm thick layer between two object glasses captured. With a reference sample (e.g. 2-methyl-4-nitroaniline) it is similar method. The samples are irradiated with a pulsed Nd: YAG laser and the Intensity of the forward scattered light with the doubled frequency is from measured with a photomultiplier for sample and reference.

The molecular hyperpolarizability β can be achieved in donor-acceptor systems Determination of the integrated strength of the absorption band and the shift of the absorption maximum can be estimated in different solvents. This method is based on the assumption that the optical nonlinearity of the Charge shift between ground state and the first electronically excited state is dominated. In this case, β is proportional to Transition moment for the lowest energy absorption, which is measured by the integrated band strength can be determined. The hyperpolarizability is also proportional to the difference between the dipole moments of the two Conditions. This difference can be caused by the shift of the Absorption wavelength between two solvents with different Dielectric constants can be estimated.

The compounds according to the invention make it possible, in particular if they are used as Poled polymers or Langmuir-Blodgett film in a layer element or in Form of a non-centrosymmetric crystal, an optical system with good non-linear optical properties. Such systems are for example for electro-optical switches, diode laser frequency doublers or optical parametric amplifiers (e.g. weaker as so-called refreshers Light signals in optical signal transmission networks).

The materials of the invention are u. a. for use in optical Components. In particular, polymers can themselves be produced as waveguides become. They are suitable, for example, as components in the field of integrated optics, sensor and communication technology, for frequency doubling  of laser light, for the production of directional couplers, switching elements, modulators, para-metric amplifiers.

The following figures explain the basic structure of a corresponding one Component.

Fig. 1 illustrates a device (100) for frequency doubling is a light wave.

The NLO-active layer 103 is embedded between a substrate (layer support) 104 and a cover layer 105 . The refractive index of (103) and (105) should be lower than that of 104 so that total reflection is possible.

The light 101 is coupled in through the end face 102 of the layer 103 or through a prism 108 or a grating (not shown). The cover layer ( 105 ) only serves to protect the active layer and can also be omitted. The active layer 103 can also be structured laterally so that the light is guided in two dimensions (perpendicular and parallel to the layer plane).

The active layer contains a compound according to the invention, which preferably has a high (above 10 ^-8 esu) second order optical susceptibility. If the thickness and width of the layer 103 and the refractive index of the substrate ( 104 ) are correctly proportional to the wavelength of the incident light, it can be achieved that the phase velocity of the coupled fundamental wave corresponds to that of the second harmonic wave. Then a lot of light of twice the frequency is generated in ( 103 ). The light beam ( 106 ) leaves the NLO-active layer on the other end face ( 107 ) or via a prism ( 109 ) or a grating (not shown). The light of the incident wavelength can be removed from filters by ( 106 ).

In an alternative embodiment (not shown) the waveguide is like this constructed that the coupled fundamental wave is guided in the waveguide, the harmonic wave but according to the so-called Cherenkov principle in that Substrate is decoupled and this leaves at its end face.  

An alternative embodiment to this component with substrate 204 and cover layer 205 is drawn in FIG. 2. The incident light beam 201 penetrates through the face 202 analogously. The light beam with additional frequency ( 206 ) leaves the component through the end face 207 . This time, the waveguide is composed of an NLO-inactive layer ( 203 ) with a high refractive index and an NLO-active layer 208 which contains the compound according to the invention, in particular in the form of an LB multilayer or a poled polymer.

A component 300 is shown in FIGS . 3a and 3b, with the aid of which a light wave can be modulated. The incident light 301 is coupled into the active waveguide layer 303 via the end face 302 , a prism (not shown) or a grating (not shown). Layer 303 is laterally structured as a Mach-Zehnder interferometer.

According to Fig. 3a two electrodes (304) are applied to both sides of the waveguide 303rd Referring to FIG. 3b, the electrodes are housed 304 above and below an arm of the interferometer.

When a voltage is applied to the electrodes 304 , the refractive index changes in 303 due to the linear electro-optical effect and thus the phase velocity of the light in the relevant arm of the interferometer. This results in an additive or subtractive superposition of the original wave and the changed wave and a modulation of the intensity of the light, which is coupled out via the end face 307 . Since most of the compounds of general formulas I, II or III according to the invention have a strong inherent color, they are well suited for such a light modulator.

FIG. 4 shows a component 400 in which there is an interaction between a first light beam of frequency ω1 and a second light beam of frequency ω2. This creates light, the frequency of which corresponds to the sum and difference of ω3 and ω4. The beams of the frequencies ω1 ( 401 ) and ω2 ( 402 ) are coupled via the end face 403 or via a prism (not shown) or a grating (not shown) into a waveguide structure 404 which is arranged on the substrate 408 . The waveguide structure 404 can be covered with a protective layer 409 .

The active layer 404 with waveguide function can consist of NLO-active LB multilayers (analogous to FIG. 1); it can also have an additional NLO-inactive layer with a high refractive index (analogous to FIG. 2).

The layer 404 can also be structured laterally in order to prepare a two-dimensional waveguide. The NLO interaction in layer 404 mixes the frequencies ω1 and ω2, ie part of the coupled intensity is converted into frequencies which correspond to the sum and the difference between the frequencies ω1 and ω2. The light, which contains these frequencies, among others, can be coupled out via the end face 407 or via a prism (not shown) or a grating (not shown).

The preparation of compounds of the general formula I in which A = COOR ⁵ and A ¹ - SO ₂ R ⁷ is possible on the basis of the work of AR Duncan et al., Synthesis (1980), 10, 806-807.

The preparation of compounds of the general formula I in which A = NO ₂ and A ¹ - COOR ⁵ is possible on the basis of the work of W. Lehnert, Tetrahedron, 1972, 28, 663-666.

The preparation of compounds of the general formula I in which A = COOR ⁵ and A ¹ = SOR ⁷ is possible on the basis of the work of R. Tanikaga et al., J. Chem. Soc., Perkin Trans. I, 1987, N4, 825-830.

The preparation of compounds of general formula I, in which A and A ^{1 are} selected from CN, CO ₂ R ⁷ and CONH ₂ , is possible on the basis of the work of J. Zabricky, J. Chem. Soc. 1901, 683.

The preparation of compounds of the general formula I in which A and A ¹ = SO ₂ R ⁷ is possible on the basis of the work of ML Oftedahl et al., J. Org. Chem. 30 (1965) 296.

The invention is illustrated by the examples below.

example 1 2-dicyanomethylene-7- (4 ′ (N (2-hydroxyethyl) -N-methylamino) styryl) -4,4 - dimethyl-4,4a- 5,6-tetrahydro (3H) naphthalene

To a solution of 1.04 g of malononitrile and 3 g of 4,4,7-trimethyl-4,4a, 5,6-tetrahydro (3H) naphthalenone in dimethylformamide (25 ml) are added piperidine (0.2 g), conc. Acetic acid (0.05 g) and acetic anhydride (0.03 g). The reaction mixture is stirred under nitrogen overnight at room temperature. The reaction mixture is then stirred at 80 ° C. for 1/2 h before 2.83 g of 4- (N- (2-hydroxyethyl) -N-methylamino) benzaldehyde are added. The mixture is then stirred at 80 ° C. for 2 h. To determine the completion of the reaction, toluene is added and the mixture is heated on a water separator. The toluene mixture is slowly distilled off while toluene is added to the mixture again. This is repeated several times. The mixture is then cooled and the solvent is distilled off in vacuo. The distillation residue is stirred in water and extracted with dichloromethane. The organic phase is dried with MgSO ₄ and the solvent is removed. The product is purified by medium pressure liquid chromatography (silica gel column with isohexane: ethyl acetate 1: 1). Yield 1.25 g (20%).

¹ H NMR (300 MHz, D-trichloromethane): 6 (ppm) 0.80 (s, 3H); 1.19 (s, 3H); 2.07 (m. 2H); 2.38 (m, 3H); 2.79 (m. 2H); 3.05 (s, 3H); 3.55 (m. 2H); 3.85 (m. 2H); 6.33 (s, 1H); 6.56 (s. 1H); 6.73 (d. 1H); 6.75 (d. 2H); 6.83 (d. 1H); 7.37 (d. 2H).
MS EI (70 eV): (M⁺) 399 melting point. 187 ° C
λmax (acetonitrile) = 515 nm The compounds according to Example 2-7 were prepared analogously to the procedure given in Example 1, with only minor changes being made to the reaction time and working up in individual cases.

Example 2 2-dicyanomethylene-7- (5'-dibutylamino-2'-thienylvinyl) -4,4-dimethyl-4-, 4a, 5,6- tetrahydro (3H) naphthalene

¹ H NMR (300 MHz, D-trichloromethane): δ (ppm) 0.96 (t, 6H); 1.26 (s, 6H); 1.36 (m, 4H); 1.64 (m, 4H); 2.29 (m, 3H); 2.42 (m, 2H); 2.74 (m, 2H); 3.29 (t, 4H); 5.72 (d, 1H); 6.23 (s, 1H); 6.28 (s. 1H); 6.48 (d. 1H); 6.84 (d, 1H); 6.92 (d, 1H). λmax (acetonitrile) = 598 nm

Example 3 2-dicyanomethylene-7- (4'-methylthiostyryl) -4,4-dimethyl-4,4a, 5,6- tetrahydro (3H) naphthalene

¹ H NMR (300 MHz, D-trichloromethane): δ (ppm) 0.81 (s, 3H); 1.20 (s, 3H); 2.10 (m, 2H); 2.39 (m, 3H); 2.50 (s, 3H); 2.80 (m. 2H); 6.39 (s, 1H); 6.61 (s, 1H); 6.80 (d. 1H); 6.88 (d. 1H); 7.22 (d, 2H); 7.39 (d, 2H). λmax (acetonitrile) = 448 nm melting point 203 ° C

Example 4 2-dicyanomethylene-7- (2 ′, 4′-dimethoxystyryl) -4,4-dimethyl-4,4a, 5,6- tetrahydro (3H) naphthalene

¹ H NMR (300 MHz, D-trichloromethane): δ (ppm) 0.81 (s, 3H); 1.19 (s, 3H); 2.07 (m. 2H); 2.39 (m, 3H); 2.81 (m, 2H); 3.85 (s, 3H); 3.87 (s, 3H); 6.36 (s, 1H); 6.45 (d, 1H); 6.52 (m, 1H); 6.59 (s, 1H); 6.84 (d, 1H); 7.19 (d. 1H); 7.48 (d, 1H) λmax (acetonitrile) = 453 nm melting point 197-199 ° C

Example 5 2-dicyanomethylene-7- (4 ′ - (dimethylaminophenyl) -1′-butadienyl) -4,4-dimethyl-4,4a, 5,6- tetrahydro (3H) naphthalene

¹ H NMR (300 MHz, D-trichloromethane): δ (ppm) 0.81 (s, 3H); 1.18 (s, 3H); 2.00-2.10 (m, 2H); 2.25-2.47 (m, 3H); 2.69-2.87 (m, 2H); 3.00 (s, 6H); 6.27 (s, 1H); 6.32-6.42 (m, 1H); 6.57 (s, 1H); 6.63-6.80 (m, 5H); 7.34 (d, 2H) λmax (acetonitrile) = 518 nm melting point 205-206 ° C

Example 6 2-dicyanomethylene-7- (4'-dimethylaminostyryl) -4,4-dimethyl-4,4a, 5,6- tetrahydro (3H) naphthalene

300 MHz ¹ H NMR (CDCl ₃ ): δ (ppm): 0.80 (s, 3H); 1.26 (s, 3H); 2.07 (m. 2H); 2.38 (m, 3H); 2.79 (m. 2H); 3.02 (s, 6H); 6.30 (s, 1H); 6.56 (s, 1H); 6.67 (d. 2H); 6.79 (m, 2H); 7.38 (d, 2H) λmax (acetonitrile) = 508 nm

Example 7 2-dicyanomethylene-7- (4'-methoxystyryl) -4,4-dimethyl-4,4a, 5,6- tetrahydro (3H) naphthalene

¹ H NMR (300 MHz, D-trichloromethane): δ (ppm) 0.81 (s, 3H); 1.20 (s, 3H); 2.03-2.13 (m, 2H); 2.29-2.49 (m, 3H); 2.70-2.90 (m, 2H); 3.84 (s, 3H); 6.36 (s, 1H); 6.60 (s, 1H); 6.81 (d, 2H); 6.90 (d. 2H); 7.43 (d, 2H) λmax (acetonitrile) = 447 nm melting point. 169-172 ° C. The compounds of the general formula III listed in the following table with R ³ -R ⁴ = H, p = 0, Q = 1,4-phenylene and n = 1 are obtainable analogously.

Example 8 (polymer)

In a 100 ml round-bottomed flask with a nitrogen blanket, 0.7 ml of a Solution of 19.02 wt .-% polyacrylic acid chloride in dioxane presented. For this drips a solution of 0.3 g of 2-dicyanomethylene-7- (4 '- (N (2-hydroxyethyl) -N-methyl styryl) -4,4-dimethyl-4,4a, 5,6-tetrahydro (3H) naphthalene (Example 1) in dried Dioxane. The reaction mixture is stirred for a few minutes at room temperature. 0.16 ml of dried pyridine are added and the mixture is stirred at room temperature Night. The reaction solution is then heated at 50 ° C. for 8 hours. To the cooled solution is then added 1 ml of methanol and again overnight  Room temperature stirred. Finally, the mixture is stirred at 50 ° C. for a further 8 hours and then the cooled solution is precipitated with slightly acidified methanol. The precipitated red-black polymer is dissolved in dichloromethane for cleaning no precipitate in methanol until (according to the DC control) low molecular weight components are more present. Yield 151 mg (35%).

The determination of the incorporation rate of the dye by means of UV-Vis spectroscopy (λmax polymer (CHCl ₃ ) = 510 nm) showed 58.3 mol% of chromophore groups in the original acid chloride groups. Tg of the polymer = 132 ° C.

The molecular hyperpolarizability β can be achieved in donor-acceptor systems Determination of the integrated strength of the absorption band and the shift of the absorption maximum can be estimated in different solvents. This method is based on the assumption that the optical nonlinearity of the Charge shift between ground state and the first electronically excited state is dominated. In this case, β is proportional to Transition moment for the lowest energy absorption, which is measured by the integrated band strength can be determined. The hyperpolarizability is also proportional to the difference between the diploma moments of the two Conditions. This difference can be caused by the shift of the Absorption wavelength between two solvents with different Dielectric constants can be estimated.

In Table 1, the solvatochromically determined values for µ × β are some Connections listed.

After the by D.J. Williams (Angew. Chemie 96, 1984, p. 640) The method can be used via the electric field-induced second-harmonic generation of the Determine values of β and thus β × µ. These EFISH values are more accurate than that Solvatochromically determined values. Table 2 shows an inventive one Compared to two prior art compounds.  

Table 1

Table 2

EFISH measurements

Claims (15)

1. Compounds of the general formula I wherein
R ¹ and R ² independently of one another are H or C ₁ -C ₄ alkyl,
R ³ and R ^{4 are} C ₁ -C ₄ alkyl or hydrogen,
A and A ¹ independently of one another NO ₂ , CN, halogen, CF ₃ , COOR ⁵ , CONR ₂ ⁶ ,
SO ₂ R ⁷ or
one of the radicals A and A ^{1 is} also hydrogen, -CO ₂ (CH ₂ ) _x ZH, SO ₃ R ⁵ , SOR ⁷ , SO ₂ NR ₂ ⁶ or S (NSO ₂ CF ₃ ) CF ₃ ,
x 2, 3, 4 or 5,
ZO, S or NH,
R ⁵ C ₁ -C ₄ alkyl
R ⁶ C ₁ -C ₄ alkyl or hydrogen,
R ^{7 is} C ₁ -C ₄ alkyl, C ₁ -C ₄ perfluoroalkyl or an optionally substituted phenyl radical,
D NR ₂ ⁸ , OR ⁸ , SR ⁸ ,
R ^{8 is} C ₁ -C ₂₂ alkyl, which can also be substituted by a terminal hydroxyl, thiol or primary or secondary amino group, or the group H (OCH ₂ CH ₂ ) _m ,
Q is an (n + 1) -valent radical which is derived from an aromatic carbocyclic or heterocyclic ring system with up to three rings,
p 0 or 1,
n 1, 2 or 3 and
m means 1, 2, 3, 4, 5 or 6. 2. Compounds according to claim 1, characterized in that Q for Phenylene or thiophenylene. 3. Compounds according to claim 1, characterized in that D represents N (CH ₃ ) ₂ , CH ₃ O or CH ₃ S. 4. Compounds according to claim 2, characterized in that
Q for phenylene and
D for HZ- (CH ₂ ) _x Y-
Z for O, NR ⁹ , S
x for a number from 1 to 18
Y for O, S, NR ¹⁰
R ⁹ , R ¹⁰ independently of one another are C ₁ -C ₄ alkyl or hydrogen. 5. Compounds according to claim 4, characterized in that Z is O and Y is NCH ₃ or O. 6. Compounds according to claim 1, characterized in that
D for NR ⁸ R ¹⁰ , OR ⁸ or SR ⁸ ,
R ^{10 is} C ₁ -C ₄ alkyl or H and
R ^{8 is} C ₁₆ -C ₂₂ alkyl
stands. 7. Layer element containing at least two monomolecular layers one Amphiphilic compound on a support, characterized in that the Amphiphilic compound is a compound according to claim 6. 8. Layer element according to claim 7, characterized in that the through the number of layers-dependent layer thickness is at least 0.1 µm.   9. Polymer containing at least 10% by weight of the remainder E. wherein R ¹ , R ² , R ³ , R ⁴ , A and A ^{1 have} the meaning given in claim 1 and Z, x and Y have the meaning given in claim 4. 10. Polymer according to claim 9 with the general formula II in which
R ¹¹ and R ¹³ independently of one another for H, CH ₃ , Cl, F or CF ₃
G for CO ₂ R ¹² , CONHR ¹² , CONR ₂ ¹² or -CN
R ^{12 represents} H or C ₁ -C ₁₀ alkyl and
E has the meaning given in claim 9. 11. Polymer according to claim 9 or 10, characterized in that the chromophoric groups E are predominantly arranged in the same direction. 12. Polymer according to claim 11, characterized in that it is in the form of a compact layer is present, which has a thickness of at least 0.1 microns. 13. Device for modulating light as a function of an electrical Voltage containing two electrodes for applying an electrical voltage, which are arranged parallel to each other and an optical waveguide that partially is arranged between the two electrodes, characterized in that the Optical waveguide, a layer element according to claim 8 or a polymer layer  according to claim 12. 14. Use of a compound according to claim 1 or 10 for the purposes of nonlinear optics. 15. Compounds according to claim 1, of the general formula (III)