JP3035682B2 - Novel nonlinear optical materials and method of converting light wavelength using them - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonlinear optical material suitable for use in various devices utilizing a nonlinear optical effect such as a wavelength conversion device. It also relates to a novel compound constituting the material. Further, the present invention relates to a method for converting a light wavelength using a nonlinear optical material.

[0002]

2. Description of the Related Art In recent years, attention has been focused on a material having a nonlinear optical material-a nonlinearity between polarization and an electric field which appears when a strong optical electric field such as laser light is applied. Such materials are generally known as non-linear optical materials and are described in detail, for example, in: "Nonlinear Optical Properties of Organic and Polymeric Materials"
CS Symposium Series 233 Edited by David J. Williams (American Chemical Society, 1983)
Annual) "" Nonlinear Optical Properties of Organic
and Polymeric Material "ACS SYMPOSIUM SERIES 23
3 Edited by David J. Williams (American Chemical Societ
y, 1983), "Organic Nonlinear Optical Materials", edited by Masao Kato and Hachiro Nakanishi (CMC, 1985), "Nonlinear Optical Properties.
Of Organic Molecular and Crystals, Volumes 1 and 2, edited by DS Schmulla and J. Jis (Academic Press 198
7th year) "" Nonlinear Optical Properties of Organic
Molecules and Crystals "vol 1 and 2 DSChemla
and J. Zyss (ed. by Academic Press).

One of the applications of the nonlinear optical material is as a second harmonic generation (SHG) based on the second-order nonlinear optical effect and a wavelength conversion device using a sum frequency and a difference frequency. Until now, inorganic perovskites represented by lithium niobate have been practically used. However, recently, it has become known that a π-electron conjugated organic compound having an electron-donating group and an electron-withdrawing group has various properties as a nonlinear optical material, which greatly exceeds the aforementioned inorganic substances. In order to form a higher-performance nonlinear optical material, it is necessary to arrange compounds having a high nonlinear susceptibility in a molecular state so as not to cause inversion symmetry. It is known that a compound having a long π-electron conjugate chain is useful for expressing a high nonlinear susceptibility, which is one of them, and various descriptions have been given in the above-mentioned literature. As is obvious, the absorption maximum wavelength becomes longer, which causes, for example, a decrease in the transmittance of blue light, which hinders the generation of blue light as the second harmonic. This also occurs in the p-nitroaniline derivative, and the effect of the transmittance at that wavelength on the efficiency of second harmonic generation is large, as described in Alignment Azema et al., Proceedings of SPII,
400 volumes, New Optical Materials (Alain
Aze'ma et al., Proceedings of SPIE, 400 volumes, Now
Optical Materials), (1983), page 186, FIG.

Therefore, the emergence of a nonlinear optical material having a high transmittance for blue light is desired. Conventionally, it has been studied to replace the carbon atom of the benzene nucleus of nitroaniline with a nitrogen atom or the like, but a satisfactory result has not always been obtained. The Applicant has also
JP-A-62-210430 and JP-A-62-210
No. 432. Further, Japanese Patent Application Laid-Open No. 62-599
No. 34, JP-A-62-23136, JP-A-63-26
No. 638, JP-B-63-31768, JP-A-63-1
No. 63827, JP-A-63-146025, JP-A-6
3-85526, JP-A-63-239427, JP-A-1-100251, JP-A-64-56425, JP-A-1-102529, JP-A-1-102530,
Many materials are disclosed in JP-A-1-237625, JP-A-1-207724 and the like. However, as described above, in order to be useful as a second-order nonlinear optical material, performance in the molecular state alone is not sufficient, and it is essential that the molecular arrangement in the aggregated state has no inversion symmetry. is there. However, at present, it is extremely difficult to predict the molecular arrangement, and the probability of existence in all organic compounds is not high.

[0005]

Accordingly, a first object of the present invention is to provide an organic nonlinear optical material exhibiting high nonlinear optical response. A second object is to provide a novel compound constituting the above material. A third object is to provide a method utilizing the response related to the conversion of the optical wavelength among the nonlinear optical responses.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventor has found that the use of the compound represented by the formula (1) as a nonlinear optical material having a nonlinear optical response makes it possible to achieve the first and second aspects of the present invention. It has been found that the third object can be achieved, and the compounds represented by the formulas (2), (3) and (4) can achieve the second purpose.

[0007]

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Equation (2)

[0009]

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Equation (3)

[0011]

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Equation (4)

[0013]

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In the formula (1), Ar ¹ and Ar ² each represent an aromatic ring comprising a 5- or 6-membered carbocyclic or heterocyclic ring. However, at least one of them is a pyrrole group, a pyrazole group, an imidazole group, a triazole group,
It is substituted by the nitrogen atom of the tetrazole group. Ar ³ and Ar ⁴ each represent an aryl group. L ¹ and L ² each represent a methine group and they are Ar ¹
Or the ortho position of the carbon atom to which L ¹ is bonded or Ar
^{The two} carbonyl groups may be linked to the ortho position of the carbon atom to which they are bound by a divalent group. Z ¹ , Z ² and Z ³ each represent a monocyclic pyrrole ring, a pyrazole ring,
It represents an atomic group necessary for forming an imidazole ring and a 1,2,4-triazole ring. n represents an integer of 1, 3 or 4. However, the tetralone derivative represented by the general formula (5) and the cyclic ketone derivative represented by the general formula (6) (wherein, R ^{1 to} R ¹⁰ may be the same or different and are unsubstituted or substituted A ¹ and A ¹ represent an aromatic hydrocarbon group, a heterocyclic group, an aliphatic hydrocarbon group, an alicyclic hydrocarbon group or a characteristic group, or a hydrogen atom which may be substituted.
² may be an unsubstituted or substituted electron-donating heterocyclic group, an aromatic hydrocarbon group or a heterocyclic group having an electron-donating characteristic group introduced therein, or the unsubstituted or substituted β-position. And a vinyl group having an electron-donating heterocyclic group, an aromatic hydrocarbon group into which the electron-donating characteristic group is introduced, or a heterocyclic group. X represents a cyclic ketone compound having at least one hydroxyl group. ) Is excluded.

More specifically, examples of the aromatic ring include a phenyl group, a naphthyl group, a 2-pyridyl group,
3-pyridyl group, 4-pyridyl group, 2-pyrimidyl group,
Examples thereof include a 2-furyl group, a 3-furyl group, a 2-thienyl group, and a 3-thienyl group. Preferably a phenyl group and 2
-A pyridyl group. They may be substituted, for example, by the following groups.
To 24, preferably 1 to 10, and more preferably 1 to 5, alkyl groups (eg, methyl, ethyl, propyl, i-propyl, butyl, t-butyl, pentyl,
sec-pentyl), an alkoxy group having 1 to 24, preferably 1 to 10, and more preferably 1 to 5 carbon atoms (e.g., methoxy, ethoxypropoxy, benzyloxy), 1 to 24 carbon atoms, preferably 1 to 10,
More preferably, 1 to 5 acylamino groups (eg, acetylamino, propionylamino, pivaloylamino, methanesulfonylamino, benzoylamino), 1 to 24, preferably 1 to 10, more preferably 1 to 5 acyloxy groups (for example, Acetyloxy, propionyloxy, benzoyloxy, benzenesulfonyloxy),

An alkoxycarbonyl group having an alkyl group having 1 to 24, preferably 1 to 10, and more preferably 1 to 5 carbon atoms (eg, methoxycarbonyl,
Ethoxy, carbonyl, propoxycarbonyl), an N-alkylcarbamoyl group having an alkyl group having 1 to 24, preferably 1 to 10, and more preferably 1 to 5 carbon atoms (eg, N-methylcarbamoyl, N, N-
Dimethylcarbamoyl, N-ethylcarbamoyl), an acyl group having 1 to 24, preferably 1 to 10, and more preferably 1 to 5 carbon atoms (eg, acetyl, propionyl, pivaloyl, methanesulfonyl, benzoyl), and the above-mentioned alkyl group Is, for example, alkoxy,
Acylamino, acyloxy, alkoxycarbonyl,
N-alkylcarbamoyl, which may be substituted with acyl,

An alkyl group having 6 to 20, preferably 6 to 10 carbon atoms (for example, phenyl, tolyl, 1-naphthyl, 2-naphthyl), a 5- to 8-membered, preferably 5- or 6-membered heterocyclic ring (for example, 2- Pyridyl, 3-pyridyl, 4-pyridyl, 2-pyrimidyl, 2-furyl, 3-
Furyl, 2-thienyl, 3-thienyl, 1-pyrrolyl,
1-pyrazolyl, 1-imidazolyl, 1-triazolyl, 1-benzimidazolyl, pyrrolidyl, piperazinyl, morpholinyl), hydroxy group, carboxy group, amino group (eg, amino, methylamino, dimethylamino, cyclohexylamino, n-octylamino), Halogen atoms (fluorine, chlorine, bromine, iodine);

The above-mentioned pyrrole group, pyrazole group, imidazole group, triazole group and tetrazole group may be substituted by the same group as the above-mentioned aromatic ring. If possible, it may be condensed with a benzene ring. The methine group may be substituted. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms (eg, methyl and ethyl), an aryl group having 6 to 10 carbon atoms (eg, phenyl and tolyl), and a halogen atom (fluorine). , Chlorine, bromine and iodine), and an unsubstituted or alkyl group is preferred.

The condensed ring formed by the continuation of L ¹ and L ² with Ar ¹ and Ar ² includes, for example, indanone and chromone. n represents an integer of 1, 3 or 4, and is preferably 1. The specific examples of the compounds used in the present invention are shown below, but the scope of the present invention is not limited only to these.

[0020]

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[0021]

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[0022]

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[0023]

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The synthesis of these compounds can be achieved by using a so-called aldol condensation reaction. That is, it can be synthesized by reacting an appropriate aldehyde and a ketone in the presence of a base catalyst. Examples of the base catalyst include sodium hydroxide, potassium hydroxide, potassium hydride, sodium methoxide, sodium ethoxide, potassium tert-butoxide, pyridine, triethylamine, 1,8-diazabicyclo [5,4,0] -7. −
Undecene (DBU), sodium carbonate, potassium carbonate, sodium hydrogen carbonate, sodium acetate, potassium acetate. Hydroxides and alkoxides are preferred, and hydroxides are particularly preferred.

The solvent used in the reaction can be selected from a range from polar solvents such as N, N-dimethylformamide (DMF) and dimethylsulfoxide (DMSO) to nonpolar solvents such as benzene and hexane. D
Polar solvents such as MF and N, N-dimethylacetamide,
Alcohols such as methanol and ethanol, and ethers such as tetrahydrofuran and 1,2-dimethoxyethane are preferable. Among them, alcohols are more preferable, and a mixed solvent of the above can be used. The reaction temperature can be selected from the range of -80 ° to 150 ° C. The range is preferably from -10 ° to 100 ° C, more preferably from 5 ° C to 85 ° C.

[0026]

Next, the present invention will be described in more detail with reference to examples. Example 1 Synthesis of Compound 1 1.86 g (10 mmol) of 4-pyrazolyl acetophenone, 1.41 g (10 mmol) of 4-chlorobenzaldehyde and 15 ml of methanol were placed in a 50 ml eggplant-shaped flask, and stirred at room temperature using a magnetic stirrer. did. To this was added a solution consisting of 0.48 g (12 mmol) of sodium hydroxide and 8 ml of methanol.
The mixture was stirred under reflux with heating for 0 minutes. After a homogeneous solution was formed once after the start of the reaction, crystals were immediately precipitated, or the reaction mixture was allowed to cool to room temperature, and then the crystals were collected by filtration. The obtained crystals were washed with methanol and air-dried. The crystals were recrystallized twice using ethyl acetate to obtain the desired product. Yield 1.
33 g (43.0% yield), melting point: 200-202 ° C ¹ H-nmr (δ ppm): 6.55 (t, 1H), 7.4
0 to 8.18 (12H) in CDCl ₃ elemental analysis value: calculated value as C ₁₈ H ₁₃ ClN ₂ O (%): C = 70.02, H = 4.27, N =
9.07 Experimental value (%): C = 70.19, H = 4.36, N =
9.04

Example 2 Synthesis of compound 7 1.73 g (10 mmol) of 4- (1H-1,2,4-triazolyl) benzaldehyde, 1-indanone 1.
50 g of 32 g (10 mmol) and 15 ml of methanol
The mixture was placed in a ml eggplant-shaped flask, and stirred at room temperature using a magnetic stirrer. Sodium hydroxide 0.4
After adding a solution consisting of 8 g (12 mmol) and 10 ml of methanol, the mixture was heated and refluxed for 1 hour. During this period, it was not completely dissolved and was not uniform. After allowing the reaction mixture to cool to room temperature, the crystals were collected by filtration. The obtained crystals were washed with methanol and air-dried. The crystals were recrystallized using a mixed solvent of acetonitrile: ethanol = 1: 1 to obtain a desired product. 2.04 g (71.1% yield) melting point 248
２４249 ° C. ¹ H-nmr (δ ppm): 4.20 (s, 2H), 7.
48 to 7.83 (5H) 8.10 (s, 4H), 8.3
0 (s, 1H), 9.45 (s, 1H) in DMS
O-d ₆ Elemental analysis: calculated for _{C 18 H 13 N 3 O (} %): C = 70.25, H = 4.56, N = 1
4.62 Experimental value (%): C = 75.30, H = 4.70, N = 1
4.67 Other compounds can be similarly synthesized. Table 1 shows their physical property values.

[0028]

[Table 1]

Example 3 In order to evaluate blue light transmittance, spectral absorption characteristics in an ethanol solution were examined. The results are shown in Table 2. Where λcuto
ff is defined as a wavelength showing a 95% transmittance in a 4 × 10 ⁻⁴ mol / liter ethanol solution.

[0030]

[Table 2]

[0031]

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The compounds of the present invention have λmax, λ
It can be seen that both the cutoff has a short wavelength and has excellent blue light transmittance.

Example 4 Measurement of second harmonic generation was performed by SKKurts.
z), TTPerry, Journal of Applied Physics (J. Appl. Phys.) 3
9, p. 3798 (1968) was carried out on a powder of the compound of the present invention. The measurement was performed using the apparatus shown in FIG. That is, the measurement was performed using pulsed YAG laser light (λ = 1.0064).
μm, beam diameter ≒ 1 mmφ, peak power ≒ 10 Mw / cm
² ) was used for the fundamental wave, and the intensity of the second harmonic was measured by the evaluation device shown in FIG. The measurement was performed by relative comparison with the intensity of the second harmonic of urea. When the intensity was low, visual observation was performed. In particular, in order to distinguish between the emission due to two-photon absorption of the fundamental wave (mainly yellow and red emission) and the second harmonic, a spectroscope was put in and only the second harmonic was measured. Further, the main purpose of the measurement by the powder method is to determine the presence or absence of nonlinearity of the substance, and the intensity ratio is a reference value of the magnitude of the nonlinearity. The results are shown in Table 3.

[0034]

[Table 3]

From Table 3, it can be seen that the compound of the present invention is useful as a nonlinear optical material and is capable of wavelength conversion.

[0036]

From the above examples, it can be seen that the compound of the present invention has a higher blue light transmittance and a sufficient SHG activity as compared with a compound conventionally conventionally known as an organic nonlinear optical material. I understand. Therefore, it is considered that the compound of the present invention is useful as a material for a wavelength conversion element, in particular, a material for generating blue light.

However, the application of the nonlinear optical material of the present invention is not limited to the wavelength conversion element, but can be used for any element utilizing the nonlinear optical effect. Specific examples of the device in which the nonlinear optical material of the present invention can be used include, in addition to the wavelength conversion device, an optical bistable device (optical storage device, optical pulse waveform control device, optical limiter, differential amplifier device, optical transistor, A / D Conversion element, optical logic element, optical multivibrator, optical flip-flop circuit, etc.), optical modulation element, phase conjugate optical element, and the like.

The compounds according to the invention can be used, for example, in the form of powders, in the form of inclusions of molecules in the host lattice (polymers, inclusion compounds, solid solutions, liquid crystals), in the form of thin layers deposited on a support (Langmea®). Blodget film, etc.), a single crystal form, a solution form and the like can be used as a nonlinear optical material in various forms. Further, the compound of the present invention is a polymer in the form of a pendant,
It can also be used by binding to polydiamolene or the like.
The details of these methods are described in the above-mentioned work by DJ Williams.

When the compound of the present invention is used as a wavelength conversion device, for example, the following method is possible. 1. Single crystallize the above compound in the core of the fiber,
A wavelength conversion element using glass as a cladding material is prepared, and a second harmonic can be generated by inputting a YAG laser beam. Further, as another method, similarly, a waveguide type wavelength conversion element can be prepared to generate the second harmonic. At this time, the Cherenkov radiation method is used as the phase matching method. However, the present invention is not limited to these, and waveguide-waveguide phase matching is also possible.

2. Next, the above compound is single-crystallized, a bulk single crystal is cut out therefrom, and a YAG laser beam is input to generate a second harmonic. At this time, an angle phase matching is used as a phase matching method. The wavelength conversion efficiency can be increased by using the bulk single crystal not only outside the laser cavity but also inside a solid laser cavity such as an LD pumped solid laser. Further, the wavelength conversion efficiency can be increased by disposing the LD in the resonator of the external resonator type LD.

For the above-mentioned single crystallization, a Bridgman method, a solvent evaporation method or the like is used. The wavelength-converted wave is used not only for the second harmonic, but also for the generation of the third harmonic and the sum difference frequency. Further, as a laser light source used as a fundamental wave at the time of wavelength conversion, for example, those shown in Table 4 can be mentioned. The wavelength of the fundamental wave is not limited at all except for the influence of the absorption of the material described above. This is because Laser & Optronics 59
Page (November 1987).

[0042]

[Table 4]

[Brief description of the drawings]

FIG. 1 shows an apparatus for measuring SHG intensity by a powder method.

[Explanation of symbols]

 Reference Signs List 1 powder sample 2 fundamental wave cut filter 3 spectroscope 4 photomultiplier tube 5 amplifier 6 (11) wavelength 1.064 μm 7 (12) wavelength 0.532 μm

Continued on the front page (51) Int.Cl. ⁷ Identification code FI C07D 233/60 C07D 233/60 249/08 249/08 257/04 257/04 401/04 401/04 403/10 403/10 405/10 405/10 405/14 405/14 409/10 409/10 G02F 1/37 G02F 1/37

Claims (4)

(57) [Claims] 1. A nonlinear optical material comprising a compound represented by the following formula (1) as a nonlinear optical responsive substance. Formula (1) In the formula (1), Ar ¹ and Ar ² each represent 5 to 6
Represents an aromatic ring composed of a membered carbocyclic or heterocyclic ring. However, at least one of them is characterized by being substituted with a nitrogen atom of a pyrrole group, a pyrazole group, an imidazole group, a triazole group, or a tetrazole group. L ¹ and L ² each represent a methine group;
It may be connected to the ortho position of the carbon atom to which L ^{1 of} r ¹ is bonded or the ortho position of the carbon atom to which the carbonyl group of Ar ² is bonded by a divalent group. However,
The tetralone derivative represented by the general formula (5) and the cyclic ketone derivative represented by the general formula (6) (wherein,
^{1 to} R ¹⁰ may be the same or different, and may be an unsubstituted or substituted aromatic hydrocarbon group, heterocyclic group, aliphatic hydrocarbon group, alicyclic hydrocarbon group or characteristic group, or hydrogen atom Is shown. A ¹ and A ^{2 each} may be an unsubstituted or substituted electron-donating heterocyclic group, an aromatic hydrocarbon group or a heterocyclic group into which an electron-donating characteristic group is introduced, or the unsubstituted or substituted β-position. And a vinyl group having an aromatic hydrocarbon group or a heterocyclic group into which an electron-donating heterocyclic group or an electron-donating characteristic group may be introduced. X represents a cyclic ketone compound having at least one hydroxyl group. ) Is excluded. 2. A compound represented by the following formula (2) or (3): Formula (3) In the formula, Z ¹ and Z ² each represent an atom group necessary for forming a monocyclic pyrrole ring, pyrazole ring, imidazole ring, and 1,2,4-triazole ring. Ar ³ and Ar ⁴ each represent an aryl group. 3. A compound represented by the following formula (4). Formula (4) In the formula, Z ³ has the same meaning as Z ¹ . n represents an integer of 1, 3 or 4. 4. A method for converting an optical wavelength according to claim 1, wherein when the optical wavelength is converted using a laser beam and a nonlinear optical material, the nonlinear optical material has no inversion symmetry.