JPH0450930A - Nonlinear optical material - Google Patents

Abstract

PURPOSE:To improve secondary nonlinear sensitivity and transparency by incorporating a specified thienyl deriv. CONSTITUTION:A thienyl deriv. represented by formula I is incorporated. In the formula I, each of R<1> and R<2> is an org. substituent such as amino, halogen or an electron attractive substituent, R<1> and R<2> may be different from each other, l is 1-5, m is 1-3, n is 0-3, A is an arom. hydrocarbon group of a hetero arom. group and Y is H, cyano, etc. The thienyl deriv. is a pi electron conjugate compd. and can cause high polarization when an electron donative substituent and an electron attractive substituent are properly introduced into the arom. ring A and the thienyl ring. An org. compd. having high nonlinear optical sensi tivity and superior transparency can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a nonlinear optical material used for optical information, optical communication, etc., and more particularly to an organic nonlinear optical material comprising a thienyl derivative.

For example, it can be used in wavelength conversion elements for semiconductor lasers, POS systems, measuring instruments, information transmission using optical fibers, and the like.

(Prior Art) Laser light has monochromaticity and directivity, that is, coherent property, and therefore exerts a specific interaction with substances. This interaction is known as a nonlinear optical effect, and can lead to harmonic generation,
It causes phenomena such as the Kerr effect, light mixing, and parametric amplification. In particular, second-order and third-order nonlinear optical effects can be expected to have a relatively large nonlinear susceptibility, so they can be applied to information processing, optical communications, etc.

Conventionally, KDP (KH2PO
4), A D P (NH4f13PO4), K T
Inorganic materials such as P (KTiOPO4) and LjNbOa have been used and applied to some measuring instruments. However, it is difficult to apply it to light-related applications due to reasons such as high purity single crystals, high price, poor light damage resistance, deliquescent property, and low nonlinear optical susceptibility. there were.

In recent years, it has been discovered that organic materials have superior nonlinear optical effects compared to inorganic materials, and since then, organic materials, which have a high degree of freedom in molecular design, have been attracting attention. In particular, 2
-C -T (Charge-
It has been thought that transfer-type organic compounds can be expected to have large nonlinear susceptibility because they induce large molecular hyperpolarizability.

However, the crystal structure of an organic compound is determined by intermolecular interactions, ie, intermolecular forces such as hydrogen bonds and van der Waals interactions. In the case of C-T type molecules having strong electron-withdrawing substituents and electron-donating substituents as described above, the structure stabilizes the crystal due to strong dipole-dipole interactions between molecules, that is, bimolecular dipoles. It is easy to form a crystal structure in which the children cancel each other out. Such a crystal structure is a centrosymmetric crystal as a molecular assembly, and is therefore nonlinearly optically inactive.

Therefore, the following method is used as a means of disrupting the central symmetry of such a crystal structure. In other words, substituents with large hydrogen bonds that can control molecular orientation such as hydroxyl groups, carboxyl groups, and amine groups, bulky substituents that can significantly change the molecular structure due to steric hindrance, and optical substituents such as amino acids or amino acid-like conductors. In addition to active substituents (D- or L-form), methods of inducing non-centrosymmetric properties have been carried out by conjugation, such as complexes with clathrates.

Further, the following points can be cited as necessary and sufficient conditions for the application of the second-order nonlinear optical material as a nonlinear optical element.

■ Extremely high nonlinear optical susceptibility ■ Fast light response speed ■ Excellent laser light transmission ■ Light damage resistance ■ Phase matching ■ Crystallinity (possibility of single crystal growth, etc.) ■ Mechanical strength ■ Processing ■ Chemically stable, such as temperature resistance [Phase] Difficult to sublimate (problem to be solved by the invention) Hyperpolarizability is high, and by introducing hydrogen-bonding substituents and optically active substituents Achieved NP without central symmetry
In the case of C-T type compounds such as P and molecules with long π-electron conjugation, large second-order nonlinear susceptibility can be expected, but they have drawbacks such as lack of transparency. Therefore, there was a drawback that the usable wavelength range was limited.

(Means for Solving the Problems) The present invention was carried out in order to solve the above-mentioned problems, and provides an organic compound having a large nonlinear optical susceptibility and excellent transparency.

In order to achieve the above object, the present invention has the following configuration. That is, the present invention is a nonlinear optical material characterized by containing a thienyl conductor represented by the following general formula (1).

(In the formula, the substituents R' and R2 may be different or the same,
Amino group, substituted amine group substituted with a group having 1 to 18 carbon atoms, cyclic amine group, alkyl group, halogen-substituted alkyl group, alkokene group, halogen-substituted alkoxy group,
Mercaptoalkoxy group, acylamide group, ester,
It is an organic substituent selected from thioester, hydroxy group, mercaptohydroxy group, halogen, and electron-withdrawing substituent, Q indicates the number and is 1 to 5, and m is 1 to 5.
It is 3. n is O~3. The ring represents an aromatic hydrocarbon group or a heteroaromatic group. Y is hydrogen, a cyano group, a carboxyl group, a carboxylic acid ester group having an alkyl group having 1 to 18 carbon atoms, or a nitro group. ) The thienyl derivative of the present invention is a π-electron conjugated compound,
Electron-donating substituents on the aromatic ring A ring and thienyl ring,
Large polarization can be achieved by appropriately introducing electron-withdrawing substituents.
It can be induced.

In other words, a large SHG susceptibility can be expected.

Furthermore, if a substituent having orientation control ability or a sterically hindering substituent is appropriately used in the substituents R I and R2, a non-centrosymmetric structure can be induced and a second-order nonlinear optically active compound can be obtained. On the other hand, as for the absorption edge wavelength, which is one of the important characteristics required, the substituents RI and R2 may be well controlled and used so as to establish a range in which a semiconductor laser can be used. Therefore, the thienyl derivative of the present invention is a promising and practical material as an SHG active material.

In the present invention, in addition to the organic substituents R' and R2, other substituents may be appropriately introduced as necessary to finely adjust the performance of the compound of the present invention.

Other substituents referred to in the present invention include amine, monomethylamine, monomethylamine, dimethylamino, diethylamino, n-butylamino, t-
Amine groups such as butylamino groups, cyclic amine groups such as piperidino, pyrrolidino, and morpholino, normal alkyl groups having 1 to 12 carbon atoms, alkyl groups such as t-butyl groups, alkyl groups containing optically active carbon, and 1-carbon atoms. -12 normal alkoxy groups, t-butquine groups, alkoxy groups containing optically active carbon, alkoxy groups such as mejycato normal alkoxy 7 groups and t-thiobutyx 7 groups having 1 to 12 carbon atoms, optically active In addition to a carbon-containing mercaptoalkoxy group, a hydroxyl group, a mercaptohydroquine group, a halogen, and an aromatic hydrocarbon group having the above-mentioned substituents can be used.

As the electron-withdrawing group, a nitro group, an ano group, a trifluoromethyl group, an incyanate group, a sulfonyl group, a carboxyl group, a carboxylic acid ester group, an acylamino group,
Halogens and aromatic groups having the above substituents can also be used. The aromatic hydrocarbon group and heteroaromatic ring referred to in the present invention include a benzene ring, a naphthalene ring, an anthracene ring,
A biphenyl ring, terphenyl ring, thiazole ring, furan ring, thiophene ring, pyrrole ring, pyridine ring, pyrimidine ring, pyrazine ring, pyridazine ring, triazine ring, tetrazine ring, etc. can be used.

The organic nonlinear optical material of the present invention can be synthesized using a general synthesis method such as Equation 2.

That is, substituted thienyl-2-acetonitrile, substituted thienyl-3-acetonitrile, substituted + The thienyl derivative of the present invention can be synthesized by carrying out a coupling reaction with the corresponding aldehyde conductor using a basic solvent such as piperidine as a catalyst.

(Example) Hereinafter, the present invention will be explained in more detail according to Examples.
The present invention is not limited to these examples.

Measurement of second harmonic generation (SHG) is performed using the powder method (SK, K
urz, T, T, Perry, 39.3798 (19
68)). The light source used for measurement was Nd;Y
It is an AG laser, which irradiates a powder sample with a laser beam with a fundamental wavelength of 11084n and generates a double wave (532nm).
was detected using a spectrometer. A schematic diagram of the second harmonic generator is shown in FIG.

The powder samples used were (a) acetone, (b) isochlohexanone, (c) THF, and (d) E. The powder was recrystallized and purified with tOH, crushed in an agate pot, and then classified into approximately 100 units. there was.

1 example of 2-thienylacetonitrile 5,0 g (40J5
04mM) and 4-methoxybenzaldehyde 5.53
g (40,6504mM) was placed in Nironasufura and dissolved with pyridine 50. The reaction solution was heated under reflux for 2 hours, and after confirming the product by TLC, it was returned to room temperature.
f[ was removed using an evaporator. The precipitated brown crude crystals were purified by recrystallization with EtOH. After separating the crystals under reduced pressure, recrystallization purification was repeated using gas chromatography until the impurity peak disappeared. The pale yellow crystals obtained were heated and dissolved in acetone and left to stand for one day, yielding fine prismatic single crystals.

The product was confirmed using nuclear magnetic resonance spectroscopy, infrared absorption spectroscopy, and elemental analysis.The obtained fine single crystal 1 was crushed in an agate pot and classified to approximately 100°, and then 880°
Intensity measurements were carried out.

880 strength;
(d) A powder sample purified by recrystallization with EtOH was similarly classified and SHG 191 was determined. The result (b)2
It was possible to confirm 880 intensities of 0.5, (c) 19.7, and (d) 20.7.

Hereinafter, (a) acetone, (b) cyclo.\xanone, and (C) THFX (d) x9nol were used as recrystallization solvents, which will be abbreviated with symbols (a) to (d), respectively.

2-thienyl acetonitrile 5,0 g (40,6
504mM) and 6.06g (40,6504mM) of 4-(N,N-dimethyl)benzaltehyde were placed in a two-neck Nasufura vessel and dissolved with piperidine somQ.

The reaction solution was heated under reflux for 2 hours, and after confirming the product by TLc, the temperature was returned to room temperature, and the solvent was removed using an evaporator. The precipitated brown crude crystals were purified by recrystallization with EtOH. After fractionating the precipitate under reduced pressure, recrystallization purification was repeated by gas chromatography until impurity peaks disappeared to obtain pure Compound 2.

The product was confirmed using nuclear magnetic resonance spectroscopy, infrared absorption spectroscopy, and elemental analysis. The obtained powder sample was crushed in an agate pot and classified into approximately 100 units, and then 880 intensity was measured.

The results (aH7.6, (b) 19.4, (c) 15.
8, (d) 880 intensity of 19.9 could be confirmed.

Real JL Doctor J Yu 2-Thienylacetonitrile 5,0 g (40,6
504mM) and 4-bromobenzaldehyde 7.5
Put 2g (40,6504mM) into Nironasufura,
Dissolve with piperidine 40 vaQ. The reaction solution was heated under reflux for 2 hours, and after confirming the product by TLC, the temperature was returned to room temperature, and the solvent was removed using an evaporator. The precipitated brown crude crystals were purified by recrystallization with M e OH. After separating the crystals under reduced pressure, the recrystallization purification was repeated until the impurity peak disappeared using gas chromatography to obtain a pure compound base.

The product was confirmed using nuclear magnetic resonance spectroscopy, infrared absorption spectroscopy, and elemental analysis. The obtained powder sample was crushed in an agate pot and classified into about 100 u, and then the 880 intensity was measured.

Results (a) 30.1, (b) 29.8, (c) 29
．． 4, (d) 880 intensity of 21.4 could be confirmed.

5.0 g of 3-thienylacetocarboxylic acid (35,211
2mM) and 4-anobenzaldehyde4. Big
(35,2112mM) was placed in Nironasufura and dissolved with 40 mQ of piperidine. The reaction solution was heated under reflux for 3 hours, the product was confirmed by TLc, and then returned to room temperature, and the solvent was removed using an evaporator. The precipitated brown crude crystals were purified by recrystallization with EtOH. After fractionating the crystals under reduced pressure, recrystallization purification was repeated using gas chromatography until impurity peaks disappeared to obtain pure Compound 4.

The N 2 product was confirmed using nuclear magnetic resonance spectroscopy, infrared absorption spectroscopy, and elemental analysis. The obtained powder sample was crushed in an agate pot and classified into about 100 u, and then 880 intensity was measured.

The result (aH2,2, (bHO,0, (c)11.2
．． (d) 880 intensity of 11.7 could be confirmed.

Support 91 2-thienylacetocarboxylic acid methyl ester 5.0g
(32,0512mM) and 4.84g (32,0512mM) of 4-nitrobenzaldehyde are placed in Nironasfura and dissolved with 60mQ of piperidine. The reaction solution was heated under reflux for 2 hours, and after confirming the product by TLC, the temperature was returned to room temperature, and the solvent was removed using an evaporator. The precipitated brown crude crystals were purified by recrystallization with EtOH. After separating the crystals under reduced pressure, we repeated the recrystallization purification using gas chromatography until the impurity peak disappeared, and confirmed the purity of the compound product using nuclear magnetic resonance spectroscopy, infrared absorption spectroscopy, and elemental analysis. The obtained powder sample was crushed in an agate pot and classified into approximately 100 IU, and then 880 intensity was measured.

Part 1 Old fruit (a) 21.1. (b) 20.0. (c)2
0.5. (d) 880 intensity of 20.7 could be confirmed.

~ The following compounds were synthesized in the same manner as Examples 1 to 5, and 880
The strength was measured.

The results of the compounds and 880 intensity are shown in Tables 1-4.

Table-1 Table-2 Table-3 (Effects of the invention) The thienyl derivative of the present compound has a long π-electron conjugated structure, and has electron-withdrawing substituents such as cyan group, carboxyl group, and carboxylic acid group. Since it has an ester group, it has a high polarizability and can be expected to have a high SHG optical susceptibility.

Therefore, greater nonlinear optical susceptibility can be expected by controlling the crystal structure by introducing an orientation control group into this skeleton and inducing non-centrosymmetric properties.

Furthermore, when a heteroaromatic ring is used as the ring, the absorption edge wavelength can be shortened, and it can be applied as a wavelength conversion element for a semiconductor laser.

The compound of the present invention has a high melting point, no sublimation, and low water absorption, so it has excellent storage stability. It also has an extremely high nonlinear optical susceptibility, and is an organic nonlinear optical compound with excellent laser resistance. material can be provided.

[Brief explanation of drawings]

Figure 1; Schematic diagram of the second harmonic generator used in the examples of the present invention -4; Q switch Nd; YAG laser; laser mirror shutter for 1064n 4; sample (powder) condensing lens 6; infrared Cut filter polychromator multi-channel photodiode MCPD drive circuit computer interface

Claims (1)

[Claims] (1) A nonlinear optical material characterized by containing a thienyl derivative represented by the following general formula (1). ▲There are mathematical formulas, chemical formulas, tables, etc.▼−−−−−−−−(
1) (In the formula, the substituents R^1 and R_2 may be different or the same, and include an amino group, a substituted amino group substituted with a group having 1 to 18 carbon atoms, a cyclic amino group, an alkyl group, a halogen-substituted alkyl group) , an alkoxy group, a halogen-substituted alkoxy group, a mercaptoalkoxy group, an acylamido group, an ester, a thioester, a hydroxy group, a mercaptohydroxy group, a halogen, and an electron-withdrawing substituent, and l is the number thereof. m is 1 to 3. n is 0 to 3. Ring A represents an aromatic hydrocarbon group or a heteroaromatic group. Y is hydrogen, cyano group, carboxyl group, carbon It is a carboxylic acid ester group or nitro group having an alkyl group of number 1 to 18.)