JP2819826B2 - Cyclobutenedione derivative and method for producing the same - Google Patents

Description

The present invention relates to a novel cyclobutenedione derivative useful as a nonlinear optical material and a method for producing the same.

(Prior Art) In the fields of optical communication and optical information processing, nonlinear optical elements play an important role. Non-linear optical materials used for the non-linear optical element include light mixing for generating sum and difference frequencies of two types of incident light having different frequencies, optical parametric as two types of light having different frequencies, and a refractive index of an optical medium. A substance that plays a very important role in optical signal processing, such as the Pockels effect or Kerr effect, which changes the wavelength, or the conversion of incident light to the second harmonic (SHG) or third harmonic (THG), as well as optical bistability. It is. Conventionally, as such a nonlinear optical material,
Mainly inorganic materials were used.

For inorganic nonlinear optical materials, KDP (KH ₂ PO ₄ )
Crystals of inorganic compounds such as lithium niobate and lithium niobate (LiNbO ₃ ) are known, but have not been sufficient to satisfy the requirements.

On the other hand, effective nonlinear optical materials have recently attracted attention as new optical element materials in the field of optoelectronics, and have been actively studied every year. In particular, organic compounds having a π-electron conjugate system have been extensively studied for material search because of the high performance and high-speed response of the molecule itself.

Generally, a crystal of an organic nonlinear optical material has a SHG coefficient 10 to 100 times larger than a crystal of an inorganic nonlinear optical material,
It is known that the light response speed is about 1000 times faster and the threshold value for light damage is large.

Recently disclosed organic nonlinear optical materials include:
-Methyl-4-nitroaniline, m-nitroaniline,
N- (4-nitrophenyl) -L-prolinol, 2-
Acetylamino-4-nitro-N, N-dimethylaniline, 4-dimethylamino-4'-nitrostilbene,
Organic compounds such as 4'-dimethylamino-N-methyl-4-stilbazolium methyl sulfate and 4'-methylbenzylidene-4-nitroaniline.
The optical nonlinearity of these organic compounds having a π-electron conjugated system is caused by the interaction between laser light as an electromagnetic wave and the π-electrons of the organic compound.
The size can be further increased by introducing an electron-withdrawing and electron-supplying substituent into the π-electron conjugated system.

However, such organic compounds generally have a large dipole moment, a strong dipole-dipole interaction during crystallization, and a centrally symmetric crystal having a structure in which two dipoles cancel each other. Is easy to form.
There is a problem that the second-order nonlinear optical effect which is important in application is not exhibited in such a centrosymmetric crystal.
Therefore, in order to break down the central symmetry, which is a problem in expressing optical nonlinearity in a crystalline state, a π-electron conjugated form is required to substitute a substituent having hydrogen bonding ability or an optically active substituent having an asymmetric carbon atom. It has been devised to introduce the compound into the organic compound at the time of molecular design. The present inventors have introduced such an optically active substituent having an asymmetric carbon atom into a π-electron conjugated system, and disclosed a specific example of a material exhibiting a larger nonlinear effect than the conventional one in Japanese Patent Application No. 1-248108. However, it is desired to further improve the nonlinear effect.

(Problems to be Solved by the Invention) In general, the properties required as a material for a nonlinear optical element include the magnitude of optical nonlinearity, light transmission, laser damage resistance, crystallinity, phase matching, and workability. , Mechanical strength, hygroscopicity and hardness.

It has been extremely difficult to select a material that satisfies the above-mentioned various properties required for practical use from conventionally known materials for organic nonlinear optical elements.

The present invention has been made in view of the above situation in the related art.

Accordingly, an object of the present invention is to improve the problems in the conventionally known materials for nonlinear optical elements, to have a larger nonlinear optical effect, and to improve the storage stability, processability and transparency of practical use. It is an object of the present invention to provide a material for organic nonlinear optical elements.

(Means for Solving the Problems) The present inventor has proposed that by introducing an appropriate substituent into a molecule, even in a compound system in which the dipole moment of the molecule is large and central symmetry is easily formed during crystallization, In particular, they have found that a material for an organic nonlinear optical element having a large second-order nonlinear optical effect can be obtained, and have completed the present invention.

The above object of the present invention is achieved by a novel cyclobutenedione derivative represented by the following general formula (I).

The cyclobutenedione ring contained in the cyclobutenedione derivative represented by the general formula (I) of the present invention has a maximum absorption wavelength (intramolecular) shown in the following examples. (Wherein, R ₁ represents an alkyl group, Z represents O or S. R ₂ represents any of the following formulas, and C ^* represents an asymmetric carbon atom.) As can be seen from the charge transfer absorption band, it has a strong electron-withdrawing property similar to a nitro group and a long π-electron conjugate system. Therefore, it is easy for the whole molecule to have a structure that is electrically largely polarized, which causes high nonlinearity.

In the cyclobutenedione derivative represented by the above general formula (I), when an amino acid derivative having an asymmetric carbon atom is introduced as a substituent, the dipole moment of the molecule itself is large. However, by controlling the orientation of molecules in the bulk structure and breaking the central symmetry, even higher non-linearity will be developed.

The cyclobutenedione derivative of the present invention represented by the above general formula (I) can be easily synthesized in good yield by the following reaction formula.

That is, the cyclobutenedione derivative represented by the general formula (II) is suspended or dissolved in a solvent such as acetone, tetrahydrofuran, methanol, ethanol, and the like. An amino acid derivative represented by the general formula (III) in an amount equivalent to or more than the dione derivative is gradually added with stirring to react. The reaction usually proceeds promptly, but can be heated if necessary. If the product precipitates with the progress of the reaction, it is filtered, and if the product does not precipitate, it is concentrated or (In the formula, X represents a chlorine atom, a bromine atom, a methoxy group or an ethoxy group, R ₁ represents an alkyl group, Z represents O or S, R ₂ represents any of the following formulas, and C ^* represents Represents an asymmetric carbon atom) What is necessary is just to precipitate by adding a poor solvent. The resulting crystals are
If necessary, it is recrystallized with a solvent such as alcohol or acetone, or purified by sublimation.

Instead of the amino acid derivative represented by the general formula (III), an acid addition salt thereof, for example, hydrochloride, bromate, p-
Using a toluenesulfonic acid salt or the like as a raw material and reacting with a cyclobutenedione derivative represented by the general formula (II) in the same manner as described above in the presence of a basic compound such as triethylamine or N-methylmorpholine. Can also be synthesized.

The cyclobutenedione derivative represented by the general formula (II) is obtained by mixing anisole and dichlorocyclobutenedione in a Friedel-Crafts solvent (eg, carbon disulfide, nitrobenzene, methylene chloride, etc.) in the presence of aluminum chloride. A method of obtaining a chlorocyclobutenedione derivative by stirring, or a method of reacting dialkoxycyclobutenedione with a trialkyloxonium salt and a halogenated solvent with anisole to obtain an alkoxycyclobutenedione derivative, And the like.

(Example 1) Synthesis of 1- (4'-methylthiophenyl) -2- (1'-hydroxymethyl-2'-phenylethylamino) -cyclobutene-3,4-dione The following structural formula (II-1) 1 g of the compound represented by (4.2 mmo
l) To 30 ml of acetone solution, add D-phenylalaninol 1 g was added and stirring continued for about 2 hours. After completion of the reaction, 20 ml of water was added as a poor solvent, and the mixture was allowed to stand in a refrigerator. afterwards,
By collecting the precipitated yellow crystals, 1- (4'-methylthiophenyl) -2- (1'-hydroxymethyl-2'-phenylethylamino) represented by the following structural formula (I-1) is obtained. -Cyclobutene-3,4-dione 1.2 g (3.4
mmol) were obtained as yellow crystals. The yield was 81%.

Melting point: 191 ° C. Maximum absorption wavelength (λmax): 366 nm (in CH ₂ Cl ₂ ) Elemental analysis C H N Calculated value 67.96 5.42 3.96 Measured value 67.85 5.40 3.88 (Examples 2 to 9) A cyclobutenedione derivative described in the column of general formula (II) in Table 3 and a general formula (III)
In the same manner as in Example 1 except that the amino acid derivative described in the column of Table 1 was used, the target product described in the column of the general formula (I) in Tables 1 to 3 was synthesized. .

About the obtained product, the elemental analysis value, the maximum absorption wavelength (λmax in CH ₂ Cl ₂ ) and the melting point were measured. Table 4 shows the results.

(Application Example) A powder sample in which the compound represented by the above structural formula (I-1) described in Example 1 was filled in a glass cell was charged with N.
When irradiated with a d: YAG laser (wavelength 1.064 μm, output 180 mJ / pulse), strong green scattered light of 532 nm due to SHG was efficiently generated.

(Effect of the Invention) The cyclobutenedione derivative of the present invention represented by the above general formula is a novel compound, and exhibits high nonlinearity.
In addition, since it is a material having excellent heat resistance, light resistance, storage stability, and processability, it is possible to fabricate nonlinear optical elements, for example, optical wavelength conversion elements, optical shutters, high-speed optical switching elements, optical logic gates, optical transistors, and the like. Can be used for

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Claims (3)

(57) [Claims] 1. A cyclobutenedione derivative represented by the following general formula (I). (Wherein, R ₁ represents an alkyl group, Z represents O or S. R ₂ represents any of the following formulas, and C ^* represents an asymmetric carbon atom.) 2. A cyclobutenedione derivative represented by the following general formula (II) is reacted with an amino acid derivative represented by the following general formula (III): A method for producing a butenedione derivative. (Where X represents a chlorine atom, a bromine atom, a methoxy group or an ethoxy group, and R ₁ represents an alkyl group) NH ₂ R ₂ (III) (where R ₂ represents any of the following formulas, C ^* represents an asymmetric carbon atom) 3. The method according to claim 1, wherein the cyclobutenedione derivative represented by the general formula (II) is reacted with an acid addition salt of the amino acid derivative represented by the general formula (III) in the presence of a basic compound. The method for producing a cyclobutenedione derivative according to claim 1.