JPH0440429A - Nonlinear optical material - Google Patents

Abstract

PURPOSE:To obtain the org. nonlinear optical material having a high nonlinear optical sensitivity and excellent laser resistance by incorporating a specific benzoazole derive. into this material. CONSTITUTION:This material contains the benzoazole deriv. expressed by formula I. In the formula I, a substituent R<1> may be different or the same and denotes the org. substituent selected from an amino group, etc., substd. with a substituent having 1 to 18C or halogen; (l) denotes the number thereof and is 1 to 5; R<2> and R<1> may be the same or different and are an org. substituent or halogen;(n) denotes the number thereof and is 0 to 4;(m) is 0 to 3; a ring A denotes an arom. hydrocarbon group or heteroarom. group. X denotes one kind of the element selected from nitrogen, oxygen and sulfur; Y denotes one kind selected from hydrogen, cyano group, etc. The high nonlinear optical sensitivity and the excellent transparency are obtd. in this way.

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 a nonlinear optical material made of a benzazole derivative. For example, wavelength conversion elements for semiconductor lasers, POS systems, measuring equipment,
It can be used for information transmission through optical fiber.

(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 (NH4H3PO4), K T P
(KTiOPO4), 1jNb03, and other inorganic materials 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 a C-T type molecule having strong electron-withdrawing substituents and electron-donating substituents as described above, a strong dipole-dipole interaction between molecules works to stabilize the crystal, that is, a bimolecular dipole. 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 bonding properties that can control molecular orientation such as hydroxyl groups, carboxyl groups, and amine groups, bulky substituents that significantly change the molecular structure due to steric hindrance, and optical substituents such as amino acids or amino acid conductors. Active substituents (
In addition to D or L forms), methods of inducing non-centrosymmetric properties by complexing with clathrates, etc., have been implemented.

Furthermore, the following points are necessary and sufficient conditions for application as a -order nonlinear optical material or nonlinear optical element.

■ Extremely high nonlinear optical susceptibility ■ Fast optical response speed ■ Excellent laser light transparency ■ Light damage resistance ■ Phase matching ■ Crystallinity (possibility of single crystal growth, etc.) ■ Mechanical strength ■ Processing ■ Moisture resistant and chemically stable @) M sublimation (problem to be solved by the invention) High hyperpolarizability, achieved by introducing hydrogen-bonding substituents and optically active substituents 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 photosensitivity can be expected, but they have drawbacks such as lack of transparency. Therefore, there was a drawback that the usable wavelength range was limited.

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

That is, the present invention is a nonlinear optical material characterized by containing a benzazole derivative represented by the following general formula (1).

(In the formula, the substituents R1 may be different or the same, and include an amine group, an amine group substituted with a substituent having 1 to 18 carbon atoms, a cyclic amine group, an alkyl group, a halogen-substituted alkyl group, an alkoxy group, a halogen-substituted An organic substituent or halogen selected from an alkoxy group, a mercaptoalkoxy group, an acylamido group, an ester group, a thioester group, a hydroxy group, a mercaptohydroxy group, a halogen, and an electron-withdrawing substituent, and Q is the number thereof. R2 represents an organic substituent or halogen which may be different or the same as R1, and n represents its number and is O-4.

m is O~3. Ring A represents an aromatic hydrocarbon group or a heteroaromatic group.

X represents one type of element selected from nitrogen, oxygen, and sulfur,
Y represents one selected from hydrogen, a cyan group, a carboxyl group, a carboxylic acid ester group, or a nitro group. ) In the pensuazole derivative of the present invention, the benzazole substituent has a nitrogen atom that can interact intermolecularly, and has a functional mechanism that can induce non-centrosymmetricity, which is a sufficient condition for SHG activity, in the crystal state. It has characteristics as a substituent (sterically hindered substituent). Furthermore, since it has an electron-donating group and an electron-withdrawing group in its molecule, it can increase optical nonlinearity. It is particularly effective to introduce an electron-donating group into the ortho position or the rose position of the aromatic ring because the resonance effect due to charge transfer interaction increases.

In addition, the compounds of the present invention have a cyan group, a kylphoxyl group, and a carboxylic acid ester group, which are strong electron-withdrawing substituents, so they have a more polarized structure and a larger S
It has an element that induces HG susceptibility.

In the present invention, in addition to the organic substitution of R1 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, monomethylamino, monoethylamino, 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-butoxy groups, alkoxy groups containing optically active carbon, mercapto normal alkoxy groups having 1 to 12 carbon atoms, t-thiobutoxy groups, etc., mercaptoalkoxy groups containing optically active carbon. In addition, a hydroxy group, a mercapto group, a halogen, and an aromatic group having the above-mentioned substituents can be used. As the electron-withdrawing group, a nitro group, a cyan group, a trifluoromethyl group, an incyanate group, a sulfonyl group, a carboxyl group, a carboxylic acid ester group, an acylamino group, a halogen, and an aromatic group having the above substituents can be used. .

The aromatic hydrocarbon group and heteroaromatic ring referred to in the present invention are a benzene ring, a naphthalene ring, an anthracene ring, a biphenyl ring, a terphenyl ring, a thiazole ring, a furan ring, a thiophene ring, a pyrrole ring, a pyridine ring, a pyrimidine ring, and a pyrazine ring. ring, pyridazine ring, triazine ring, tetrazine ring, etc. can be used.

The organic nonlinear optical material of the present invention can be synthesized using general synthesis methods such as formulas (1) to (4).

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

Second harmonic generation (SHG) is measured using the powder method (S).

K, Kurz, T, T, Perry, 39.3798 (
1968)). The light source used for measurement was Nd
; It is a YAG laser, and the powder sample 1 〇- material is irradiated with a laser beam with a fundamental wavelength of 1064 nm, and the generated double wave (532 nm) is used for spectroscopy. The powder sample is (a) acetone, (b) ethanol, (
c) Toluene (d) Ethyl acetate, (d) Powder purified by recrystallization with pyridine was crushed in an agate pot, and then classified into about 100 u.

Support 11 2-benzimidazolylacetonitrile 5.0g (3
1,8471mM) and 4.34g (31,8471mM) of p-methoxybenzaldehyde were added to a 100J Nilo flask, and 601nQ of pyridine was poured into the flask.

After heating under reflux for a working time, the mixture was cooled to room temperature, and then poured into 100 g of methanol to precipitate crystals.

The precipitated crystals were collected under reduced pressure and purified by silica gel column chromatography to obtain 7.88 g of crude crystals (yield;
90%). This was purified by recrystallization with ethanol to obtain pale yellow needle crystals of the coupling product↓.

The product was confirmed by nuclear magnetic resonance spectroscopy, 1. R.

This was done by spectral and elemental analysis.

When the SHG intensity of the obtained product was measured by the above method, it was found to be (a) 23.9 (acetone) relative to urea.
, (b) 11. 7 (ethanol), (c)3
It was possible to confirm the generation of SHG of 5.0 (toluene), (d) 27.3 (ethyl acetate), and (e) 22.8 (pyridine).

Support 19t 2-Benzimidazolylacetonitrile 2. 0g (
12,7388mM) and 4-(N,N-dimethylamine)benzaldehyde 1.9g (12,7388mM)
into a 100IIQ Nilo flask, add 60mQ of pyridine
poured into it. - heating under reflux for an hour and then cooling to room temperature;
Crystals were precipitated. The precipitated crystals were collected under reduced pressure and purified by silica gel column chromatography to obtain 2.94 g (yield: 80%) of crude crystals. This was recrystallized and purified with ethanol, and the pale yellow plate-like crystals of the coupling product 2
I got it.

The product was confirmed by nuclear magnetic resonance spectroscopy, 1. R.

This was done by spectral and elemental analysis.

When the SHG intensity of the obtained product was measured by the above method, it was found to be (a) 85. '4 (acetone), (b) 59. 2 (ethanol), (c) 6
7, 8 () Luen), (d) 88. SHG of 1 (ethyl acetate), (e) 88, 7 (pyridine)
I was able to confirm the occurrence.

Actually] 1 case! 2-benzimidazolylacetonitrile 5.0g (3
1,8471mM) and p-cyanobenzaldehyde 4
．． 17g (31,8471mM) was added to a 100IIIQ double flask and poured with 60IoQ of pyridine.

After heating under reflux for three hours, the mixture was cooled to room temperature, and then poured into 120 ml of methanol (!) to precipitate crystals.

The precipitated crystals were separated under reduced pressure and purified by silica gel column chromatography to give 8.23 g of crude crystals (yield;
96%). This was purified by recrystallization with ethyl acetate to obtain pale yellow needle crystals of the coupling product. The product was confirmed by nuclear magnetic resonance spectroscopy, 1. R, spectra and elemental analysis.

When the SHG intensity of the obtained product was measured by the above method, it was found to be (a) 58.0 (acetone) relative to urea.
, (b) 67.4 (ethanol), (c) 88.1
() toluene), (d) 68.5 (ethyl acetate), (
e) 70. 1 (pyridine) SHG generation could be confirmed.

The force obtained with support 17 ILIJ-, Purifugu product 5.0 g (18,
1818mM) was placed in a 100 wQ Niro flask, and then 60□Q of 65% concentrated sulfuric acid was added and heated and stirred at 100''C for a working time.The product was checked over time using a thin layer Calofft.Reaction After the passage, the reaction solution was cooled to room temperature, and the precipitated crude crystals were collected under reduced pressure.

The obtained crude crystals were purified by recrystallization with acetone to obtain 5.12 g of pale yellow needle crystals (yield: 96%).

I was able to confirm it.

[5.0 g of carboxylic acid derivative obtained by LIF (17,000
88mM) into a 100J Nilo flask, then 65
% concentrated sulfuric acid was added, and the mixture was heated and stirred at 150° C. for a working time. Confirmation of the product was carried out over time using thin layer Calofft. After the reaction was completed, the reaction solution was cooled to room temperature, and the precipitated crude crystals were collected under reduced pressure.

The obtained crude crystals were purified by recrystallization with acetone to obtain 4.01 g of pale yellow needle crystals (yield: 94%).

When the SHG intensity of the obtained product was measured by the above method, it was found to be (a) 38.8 (acetone) relative to urea.
, (b) 34. 9 (ethanol), (C)30.
1 (toluene), (d) 37.2 (ethyl acetate),
(e) The SHG intensity of the product obtained by generating 34.5 (pyridine) was measured by the above method, and it was found that (a) 70.2 (acetone), (
b) 68. 5 (ethanol), (c) 39.3
() Ruen), (d) E34. 1 (ethyl acetate), (e) Et9.9 (pyridine) generation of SHG could be confirmed.

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

The measurement results of SHG intensity (to urea ratio) are shown in Tables 1 to 9.

v7Iil gu4-+3 y Table Table Table Table Table Table Table 8 Table Table 9 (Effects of the invention) The compound of the present invention has an electron-withdrawing substituent such as a cyan group at the end of the π-electron conjugated structure. Furthermore, it has a benzimidazolyl group, benzthiazolyl group, and benzoxacylyl group with stronger electron-attracting force at the same position of vinylidene, so that it has a high polarizability in the ground state.

Therefore, if the crystal structure is controlled by introducing an orientation control group into this skeleton and non-centrosymmetricity is induced, greater nonlinear optical susceptibility can be expected.

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 1; Q switch Nd; YAG laser 2; 10B4n laser mirror 3; Shutter 4; Sample (powder) 5; Focusing light Lens 6; infrared power, filter 7; polychromator 8; multichannel photodiode 9; MCPD drive circuit

Claims (1)

[Claims] (1) A nonlinear optical material characterized by containing a benzazole derivative represented by the following general formula (1). ▲There are mathematical formulas, chemical formulas, tables, etc.▼−−−−−−−−(
1) (In the formula, the substituents R^1 may be different or the same, and include an amino group, an amino group substituted with a substituent having 1 to 18 carbon atoms, a cyclic amino group, an alkyl group, a halogen-substituted alkyl group, an alkoxy group, halogen-substituted alkoxy group, mercaptoalkoxy group, acylamido group, ester group, thioester group, hydroxy group, mercaptohydroxy group,
It is an organic substituent or halogen selected from halogen and electron-withdrawing substituents, and l indicates its number, 1 to 5.
It is. R^2 is an organic substituent or halogen which may be different from or the same as R^1, and n indicates its number and is 0 to 4.
It is. m is 0-3. Ring A represents an aromatic hydrocarbon group or a heteroaromatic group. X represents one element selected from nitrogen, oxygen, and sulfur,
Y represents one selected from hydrogen, a cyano group, a carboxyl group, a carboxylic acid ester group, or a nitro group. )