JPH04305630A - Organic nonlinear optical material - Google Patents

Abstract

PURPOSE:To obtain an organic compound having high nonlinear optical effect and having no absorption region in a visible region, consisting of 2-thiophenyl carboxylic acid derivative shown in specified expression. CONSTITUTION:This organic nonlinear optical material consists of a 2-thiophene carboxylic acid derivative. For instance, the thiophene derivative generates intensive higher harmonics(532nm green light) by irradiating it with ND:YAG laser(1064). And the 2-thiophene derivative is a transparent colorless and high melting point crystal at a visible region. And it is usable not only at a state of single crystal but also at a state of a film, a fiber and a vapor-deposited film, and is usable compound as a nonlinear optical material used for an optical wavelength conversion element, an optical switching element, etc.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to nonlinear optical materials comprising novel 2-thiophenecarboxylic acid derivatives and thienopyrimidine derivatives having excellent nonlinear optical effects.

Nonlinear optical materials have effects such as wavelength conversion and intensity modulation of light when irradiated with light such as laser light, and are essential materials in optoelectronic fields such as optical recording, information processing, and optical communication. It has been attracting attention and active research and development is being carried out.

0003

[Prior Art] Conventionally, potassium dihydrogen phosphate (KDP) and lithium niobate (LN) have been used as nonlinear optical materials.
Inorganic crystals such as these have been put into practical use as optical wavelength conversion elements for laser light, optical shutters, etc., but these inorganic crystals have poor operability and do not have sufficient nonlinear optical effects. On the other hand, it is known that certain organic compounds such as urea and 2-methyl-4 nitroaniline (MNA) have large nonlinear optical effects. However, the nonlinear optical effects of these organic compounds are still not fully satisfied.
In addition, compounds with relatively high nonlinear optical effects are themselves considerably colored and have long wavelength absorption, which limits the wavelength range in which they can be used.

On the other hand, 2-thiophenecarboxylic acid derivatives and thienopyrimidine derivatives having various substituents are known compounds, and their physiological activities such as pharmacological activities have been investigated. However, there is no description of the two types of thiophene derivatives of the present invention, and as a matter of course, nothing is known about the nonlinear optical activity of the compounds.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an organic compound that has a high nonlinear optical effect and has no absorption in the visible region.

[0006]

[Means for Solving the Problems] Based on the knowledge that π-electron-conjugated organic compounds have large nonlinear optical effects, the present inventors have synthesized thiophene derivatives and measured their nonlinear optical effects. As a result, the inventors discovered that certain thiophene derivatives have high nonlinear optical effects and completed the present invention.

That is, the present invention is based on the general formula [I]

000
8]

A nonlinear optical material characterized by comprising a 2-thiophenecarboxylic acid derivative represented by the following formula [II]

[
0009

This is an organic nonlinear optical material characterized by being composed of a thienopyrimidine derivative represented by the following formula.

Although it is not clear why the thiophene derivative of the present invention exhibits high nonlinear optical activity, for example, in the case of the 2-thiophenecarboxylic acid derivative represented by formula [I], the methoxycarbonyl group at the 2-position and the methoxycarbonyl group at the 3-position Possible factors include effective intramolecular polarization due to the acetylamino group and the phenyl group at the 5-position, and a crystal structure without inversion symmetry. This means that
3-benzoylamino-2-thiophenecarboxylic acid methyl ester, 3-
The nonlinear optical activity of benzoylamino-5-phenyl-2-thiophenecarboxylic acid methyl ester and the like can also be inferred from the fact that it is inactive. In addition, in the case of the thienopyrimidine derivative represented by formula [II], the methyl group at the 2-position and the 4-position
Possible factors include effective intramolecular polarization due to the methylthio group at the position and a crystal structure without inversion symmetry. This indicates that 2-phenyl-4-
The nonlinear optical activity of methylthiothienopyrimidine and the like can also be inferred from the fact that it is inactive.

The two thiophene derivatives of the present invention are colorless crystalline solids and generally have an infrared absorption spectrum, 1H
- It can be confirmed that the compound is a compound represented by the above formula [I] or formula [II] by means such as nuclear magnetic resonance spectroscopy, mass spectrometry, and elemental analysis.

The method for producing the thiophene derivative of the present invention is not particularly limited, and any method may be used. As a typical production method that is generally suitably used, the formula [I ] A 2-thiophenecarboxylic acid derivative can be obtained. Also, 3-
Obtaining the thienopyrimidine derivative represented by formula [II] of the present invention by methylating 2-methylthienopyrimidine-4-thione produced by the reaction of acetylamino-2-cyanothiophene and sodium hydrosulfide. Can be done.

[0013]

[Effect of the invention] The thiophene derivative provided by the present invention is
For example, a strong second harmonic (green light of 532 nm) is generated by irradiation with a Nd:YAG laser (1064 nm).

The thiophene derivative provided by the present invention is a colorless crystal with a high melting point and is transparent in the visible region. That is, the compound of the present invention can be used not only as a single crystal but also in various forms such as films, fibers, and vapor deposited films, and is a compound useful as a nonlinear optical material for materials such as optical wavelength conversion elements and optical switching elements. It is.

[0015]

EXAMPLES The present invention will be explained in more detail below with reference to production examples and examples, but the present invention is not limited to these production examples and examples.

Production Example 1 Methyl 3-amino-5-phenyl-2-thiophenecarboxylate (5.00 g), potassium carbonate (2.08 g) and dioxane (100 ml) were added to an eggplant flask.
Acetyl chloride (2.19 g) was added dropwise while stirring, and the mixture was stirred at room temperature for 10 hours. The solvent was removed from the reaction solution, and the mixture was extracted with chloroform. Methyl 3-acetylamino-5-phenyl-2-thiophenecarboxylate (4.85 g) was obtained by drying over anhydrous sodium sulfate, filtering, removing chloroform, and drying the obtained solid. The yield was 82%. Compound no. No. Set to 1.

[0017] mp. : 124℃ IR (cm-1): 1704 (C=O), 1674 (C
=O) 1H-NMR (in CDCl3, based on tetramethylsilane): δ = 2.21 ppm (s, 3H), 3.88p
pm (s, 3H), 7.10-7.75ppm (m, 5
H), 8.32ppm (s, 1H) 10.40ppm (bs, 1H) Mass: m/e = 275 (M+), 232
Elemental analysis value (C14H13NO3S=275.32)
Measured value (%) C, 60.89
; H, 4.83; N, 5.20
Calculated value 61.07
4.76 5.09 Production Example 2 3-acetylamino-2-cyanothiophene (3.73 g) and sodium hydrosulfide hydrate (20.0 g) were placed in an eggplant flask.
49 g) and ethanol (170 ml) were added thereto, and the mixture was heated under reflux for 10 hours. The solvent was removed from the reaction solution, and the mixture was extracted with chloroform. The solid obtained by removing chloroform was recrystallized with water to obtain 2-methyl-thienopyrimidine-4-thione (2.50 g). The 2-methyl-thienopyrimidine-4-thione (0.
5 g) and 1N sodium hydroxide (36 ml) were added thereto, and methyl iodide (25.08 g) was added dropwise with stirring, followed by stirring at room temperature for 5 hours. Water was added and extracted with ethyl acetate. After drying with anhydrous sodium sulfate, the solvent was removed and the resulting solid was dried to give 2-methyl-4-
Methylthiothienopyrimidine (0.24g) was obtained. The yield was 44%. Compound no. No. Set it to 2.

The results of instrumental analysis of the product are shown below.

[0019] mp. : 120℃ IR (cm-1): 1530 (C=N) 1H-NMR (
(in CDCl3, based on tetramethylsilane): δ=2.6
0ppm (s, 3H), 2.78ppm (s, 3H),
7.38ppm (d, 1H), 8.25ppm (d, 1H)
H) Mass: m/e=196 (M+), 149
Elemental analysis value (C8H8N2S2=196.29)
Measured value (%) C, 48.82;
H, 4.03; N, 14.13
Calculated value 48.95
4.11 14.27 Example 1 Second harmonic generation (SHG) was measured using the compounds synthesized in Production Examples 1 and 2. The measurement was performed by Kurt
This is an improved method of the powder method devised by Z. et al., and is a method for quickly and easily predicting the intensity of harmonics emitted by a single crystal. That is, a pulse of a Q-switched Nd:YAG laser (wavelength 1064 nm) with an average output of 3.5 W was used as a light source. Laser light is focused through a lens,
The light was incident on the sample sandwiched between glasses at an angle of 45 degrees with respect to the glass surface. The generated harmonics were detected by a photon counting head through a filter placed at a distance of 5 cm from the glass surface and transmitting only the SH light. SHG was measured using urea and 2-methyl-4-nitroaniline as standard samples, and the samples were evaluated based on the intensity ratio with urea. The sample powder was ground as homogeneously as possible in an agate mortar. As a result, compound no.
The SHG activity of Compound No. 1 is 7 times that of urea. The SHG activity of 2 was 6 times that of urea.

Claims (2)

[Claims] 1. An organic nonlinear optical material comprising a 2-thiophenecarboxylic acid derivative represented by the general formula [I]. 2. An organic nonlinear optical material comprising a thienopyrimidine derivative represented by the general formula [II].