JPH03112961A - Squarylium derivative and production thereof - Google Patents

Abstract

NEW MATERIAL:The squarylium derivative of formula I (X is H, methyl, ethyl or methoxy; R is -CO2-t-C4H9 or -CH2OH; * represents asymmetric carbon). EXAMPLE:4-(4'-Dimethylaminophenyl)-3-(2'-t-butoxycarbonylpyrrolidyl)- cyclobutene-1,2-dione. USE:An organic non-linear optical material. It is a practical material exhibiting large non-linear optical effect and having improved storage stability and processability. PREPARATION:The squarylium derivative of formula I can be produced by reacting a squarylium derivative of formula II (Y is Cl, Br, methoxy or ethoxy) with a pyrrolidine compound of formula III.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a novel square aryllium derivative useful as a nonlinear optical material and a method for producing the same.

BACKGROUND OF THE INVENTION Nonlinear optical elements play an important role in the fields of optical communication and optical information processing. The nonlinear optical materials used in nonlinear optical elements can be used for light mixing that generates a frequency that is the sum of two types of incident light with different frequencies, optical parametric that produces two types of light that have different frequencies, and changing the refractive index of the source medium. The Pockels effect, the Kerr effect, or the second harmonic of the incident light (SHG)
) or third harmonic (THG), which perform extremely important functions in optical signal processing. Conventionally, such nonlinear optical materials have been classified into inorganic and organic types. It has been discovered that

Regarding inorganic nonlinear optical materials, KDP (KH2P
Although crystals of inorganic compounds such as 04) and lithium niobate (LiNbO*) are known, they are not sufficient to fully satisfy the requirements.

On the other hand, organic nonlinear optical materials have recently attracted attention as materials for new optical elements in the field of optoelectronics, and research is increasing year by year. especially,
Organic compounds with a π-electron conjugated system have been extensively studied for material exploration due to their high performance as a single molecule and high-speed response.

In general, it is known that crystals of organic nonlinear optical materials have a SHG coefficient 10 to 100 times larger, a photoresponse speed of about 1000 times faster, and a higher threshold for photodamage than crystals of inorganic nonlinear optical materials. It is being

Conventionally known organic nonlinear optical materials include 2-methyl-4-nitroaniline, ■-nitroaniline, and N-
(4-nitrophenyl)-L-prolinol, 2-acetylamino-4-nitro-N, N-dimethylaniline,
4-dimethylamino-4'-nitrostilbene, 4'-
Dimethylamino-N-methyl-4-stilbazolium methyl sulfate and 4'-methylbenzylidene-4-
Examples include organic compounds such as nitroaniline.

The nonlinearity of organic compounds with these π-electron conjugated systems is
This is caused by the interaction between laser light as an electromagnetic wave and π electrons of organic compounds, and this interaction can be further enhanced by introducing electron-withdrawing or electron-donating substituents into the π-electron conjugated system. Can be made larger.

However, in such organic compounds, the dipole moment generally increases, and the dipole-dipole interaction during crystallization becomes stronger, resulting in a central symmetry structure in which the dipoles of two molecules cancel each other out. It becomes easier to form crystals. There is a problem in that the second-order nonlinear optical effect, which is important in practical applications, does not occur in such centrosymmetric crystals. In order to break the central symmetry, which is a problem in developing nonlinearity in the crystalline state, substituents with hydrogen bonding ability and optically active substituents with asymmetric carbon atoms are added to molecules of π-electron conjugated organic compounds. Efforts have been made to introduce this at the time of design.

Problems to be Solved by the Invention In general, the properties required for materials for nonlinear optical elements include the magnitude of optical nonlinearity, optical transparency, laser damage resistance, crystallinity, phase matching, processability, and mechanical properties. Examples include strength and hygroscopicity.

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

The present invention has been made in view of the above-mentioned actual situation in the prior art.

Therefore, an object of the present invention is to improve the problems in the conventionally known materials for nonlinear optical elements, to provide a practical organic nonlinear optical device that has a large nonlinear optical effect, and has improved storage stability and processability. The purpose is to provide materials.

Means for Solving the Problems The present inventor has proposed that even if the molecular dipole moment is large and the compound system is likely to form central symmetry during crystallization, by introducing an appropriate substituent into the molecule, especially 2 The present invention was completed by discovering that an organic nonlinear optical material with the following large nonlinear optical effect can be obtained.

The above object of the present invention is achieved by a novel squarelilium derivative represented by the following general formula (1) (wherein, X represents a hydrogen atom, a methyl group, an ethyl group or a methoxy group, and R
is -CO2-L-Cd H! Or represents -CH, OH. Note that * means an asymmetric carbon atom. ) The cyclobutenedio ring contained in the squarylium derivative represented by the above general formula (1) of the present invention has a strong electron-withdrawing property comparable to that of the nitro group, as evidenced by the maximum absorption wavelength shown in the examples below. In addition, it has a long π-electron conjugated system.As a result, the entire molecule takes on a highly electronically polarized structure, which causes high nonlinearity.

In addition, in the squalium derivative represented by the above general formula (1), since a substituent having an asymmetric carbon atom is introduced, even if the dipole moment of the molecule itself is large, the molecule in the bulk structure control the orientation of
By breaking the central symmetry, large optical nonlinearity will occur.

The squarylium derivative represented by the above general formula (T) of the present invention can be easily synthesized in good yield according to the reaction formula shown below.

(I)0 (In the formula, Y represents a bromine atom, a methoxy group, or an ethoxy group, and X, R, and * each have the same meaning as defined above.) That is, the general formula ( The squarylium derivative represented by n) is suspended or dissolved in a solvent such as acetone, tetrahydrofuran, methanol, ethanol, etc., and then, in the resulting suspension or solution,
A pyrrolidine compound represented by σ general formula (III) in an amount equivalent to or more than the square aryllium derivative is gradually added with stirring to react. The reaction proceeds stubbornly and rapidly, but it is possible to heat it if necessary. If the product precipitates as the reaction progresses, filter it, or if the product does not precipitate, concentrate or
Alternatively, it may be precipitated by adding a suitable poor solvent. The obtained crystalline W is recrystallized using a solvent such as alcohol or acetone, or purified by sublimation, if necessary.

Instead of the pyrrolidine compound cedar represented by the above general formula (m), its acid addition salts, such as hydrochloride, rogate salt, p-toluenesulfonate, etc., are used as raw materials, and triethylamine, N-methylmorpholine It is also possible to react with the squareylium derivative represented by the general formula (II) in the same manner as described above in the presence of a basic compound such as.

The squarylium derivative represented by the above general formula (n) can be prepared by, for example, dimethylaniline compound and dichlorocyclobutenedione in a Friedelkraff solvent (for example, carbon disulfide, nitrobenzene, etc.) in the presence of aluminum chloride.
(e.g. methylene chloride) to obtain a chlorocyclobutenedione derivative, or by reacting dialkoxycyclobutenedione with a dimethylaniline compound together with a trialkyloxonium salt and a halogenated solvent to form an alkoxycyclobutenedione derivative. It can be produced by a method of obtaining a cyclobutenedione derivative, etc.

Example Hereinafter, the present invention will be explained by examples.

Example 1 4-(4'-dimethylaminophenyl)-3-(2'-
Synthesis of t-butoxycarbonylpyrrolidinyl)-cyclobutene-1°2-dione 1 g (4,24 m
1.5 m of I 1,-proline-t-butyl ester, Q, was added to 50 m of an acetone solution of at) with stirring and allowed to react. After reacting for 2 hours,
The solvent was distilled off, and the residue was recrystallized from methanol to obtain 4-(4'-dimethylaminophenyl)-3-(2'-L-butoxycarbonyl) represented by formula (1). 1.3 g (3.5 mmol) of (pyrrolidinyl)-cyclobutene-1,2-dione was obtained as yellow crystals.

Yield 83%.

Melting point 2115℃ Maximum absorption wavelength λ11ax: 399nm (Cl12
(in C12) Elemental analysis CHN Direct calculation 67.90 7.33 7.54 Measured value 67.63 7.53 7.50 Examples 2 to 6 Listed in the general formula (II) column of Table 1 as the raw material The Li described in the general formula (1) column of Table 1 was prepared in the same manner as described in Example 1 except that the square lium derivative of The product was synthesized.

Regarding the obtained product, elemental analysis value, maximum absorption wavelength λ
WaX and melting point were measured. The results are shown in Table 2.

Below is a blank space Table 2 Application examples The compound represented by the above 1R formula (1') described in Example 1 was added to a powder sample filled in a glass cell with Nd
: YAG laser (wavelength 1.064 leap, output 180i
J/pulse), 532n caused by SHG
m of green scattered light was generated. When the strength was measured, it was 8 times as strong as the one-pass measurement of urea powder under similar conditions.

Effects of the Invention The squareylium derivative represented by the above general formula (1) of the present invention is a novel compound, exhibits high nonlinearity, and has excellent heat resistance, light resistance, storage stability, and processability. Since it is a material that can be used in the production of nonlinear optical elements, such as optical wavelength conversion elements, optical shutters, high-speed optical switching elements, optical logic gates, optical transistors, etc.

Claims (1)

[Claims] (1) A squarylium derivative represented by the following general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, X represents a hydrogen atom, methyl group, ethyl group, or methoxy group, and R represents -CO_2-t-C_4H_9 or -CH_2OH. Note that * means an asymmetric carbon atom.) (2) General formula (II) below ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ (II) (In the formula, Y represents a chlorine atom, a bromine atom, a methoxy group, or an ethoxy group. A squareylium derivative represented by the following general formula (I
II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(III) (In the formula, R is -CO_2-t-C_4H_9 or -C
Represents H_2OH. Note that * means an asymmetric carbon atom. ) The method for producing a squarilium derivative according to claim 1, which comprises reacting a pyrrolidine compound represented by: (3) A patent claim characterized in that the squarylium derivative represented by the general formula (II) and the acid addition salt of the pyrrolidine compound represented by the general formula (III) are reacted in the presence of a basic compound. A method for producing a squarylium derivative according to item 1.