JPH0389219A - Nonlinear optical material - Google Patents

Abstract

PURPOSE:To enhance the nonlinear optical sensitivity of the above material and to enhance the preservation stability and laser resistance by using a specific dibenzyl ketone derivative. CONSTITUTION:The dibenzyl ketone deriv. expressed by formula I is used as the above material. In the formula, A, B denote a (substd.) arom. hydrocarbon group; x denotes 0, 1 ; y denotes 0 to 4. The resonance effect by the interaction of charge transfer phases is increased when an electron donative group is introduced into the ortho position or para position of the groups A, B. The compounds expressed by formula II, etc., are usable. This material is obtd. by bringing the corresponding acetone or cycloalkanone and substd. benzaldehyde deriv. into dehydration condensation reaction in the presence of a catalyst.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to nonlinear optical materials used in optical information, optical communication, etc., and more specifically relates to organic nonlinear optical materials comprising dibenzalketone derivatives, such as semiconductors. It can be used in optical-related equipment such as wavelength conversion elements for lasers and optical spatial modulators.

(Prior Art) Laser light has monochromatic, directional, and coherent properties, so it exerts specific interactions with substances.

This interaction is known as a nonlinear optical effect, and causes phenomena such as harmonic generation, Kerr effect, optical mixing, and parametric amplification.In particular, second- and third-order nonlinear optical effects can be expected to have a relatively large nonlinear susceptibility. It can be applied to information processing, optical communication, etc.

Conventionally, DP (KHtPO4) has been used as a nonlinear optical material.
Inorganic materials such as , DP (NH4-covered Pen), LiNbOs, etc. have been used and applied to measuring instruments for - parts. 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, since it has been discovered that organic materials have superior nonlinear optical effects compared to inorganic materials, organic materials, which have a high degree of freedom in molecular design, have attracted attention.

In particular, C-T (Charge-Tr
It has been thought that large nonlinear susceptibility can be expected because ansfer ) type organic compounds 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 a strong electron-withdrawing direct substituent group and an electron-donating substituent group as described above, a strong dipole-dipole interaction between molecules acts to stabilize the crystal, i.e., a bimolecular structure. Such a crystal structure, which tends to have a crystal structure in which the dipoles of

Therefore, the following method is used as a means of disrupting the central symmetry of such a crystal structure.

■ Introduction of substituents that have a large contribution to hydrogen bonding ■ Introduction of bulky substituents that induce molecular twisting due to steric hindrance ■ Introduction of optically active substituents ■ Complexes with clathrates ■ Recrystallization organic solvents (Slow evaporation method, etc.) Typical compounds synthesized taking these methods into consideration are MNA and NPP (n-(P-nitrophenyl)prolinol), and have a fairly large second-order nonlinear susceptibility. It is known that this phenomenon occurs, but it is not yet sufficient.

In general, the following points are necessary and sufficient conditions for the application of a second-order nonlinear optical material as a 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 ■ Chemically stable, such as moisture resistance [Phase] Difficult to sublime (problem to be solved by the invention) C-T types such as MNA and NPP, which have large hyperpolarizability and lack central symmetry For molecules and molecules with long π-electron conjugation,
Although a large second-order nonlinear susceptibility can be expected, it has drawbacks such as not providing a susceptibility high enough for practical use.

(Means for Solving the Problem) The present inventors have made extensive research efforts in order to obtain an excellent organic compound having a large nonlinear optical susceptibility, which is the above-mentioned problem, and as a result, they have finally completed the present invention. That is, the present invention is a nonlinear optical material characterized by containing a dibenzalketone derivative represented by the following general formula (I).

[In the formula, is O or 1, and y is an integer of 0 to 4. A and B are aromatic hydrocarbon groups with or without a substituent, and may be the same or different.] The dibenzalketone derivative of the present invention is an element for increasing hyperpolarizability. Appropriate intramolecular polarization and ground state can be achieved by having a π-electron conjugated structure, adding a carbonyl group as an electron-withdrawing substituent to the intramolecular core part, and adding various substituents to the aromatic ring. Since excited state interactions can be induced, optical nonlinearity can be increased. Introducing an electron-donating group at the ortho or para position of the aromatic ring is particularly effective because it increases the resonance effect due to charge transfer interaction.

In the present invention, the aromatic hydrocarbon groups A and B are specifically a benzene ring, a naphthalene ring, an anthracene ring, a biphenyl ring, a terphenyl ring, a binaphthyl ring, a thiazole ring, a furan ring, a thiophene ring, a pyrrole ring, a pyridine ring,
Examples include a pyrimidine ring, pyrazine ring, pyridazine ring, triazine ring, and tetrazine ring.

In the present invention, it is preferable that at least one of the aromatic hydrocarbon groups A, B has an electron-donating group.

The electron-donating group is a substituent that satisfies σ<O with the substituent constant σ of Ha+smett, and includes amino, monomethylamino, monoethylamino, dimethylayono, diethylamino, n-butylamino, t-butylamino groups, etc. aeno group, cyclic amino group such as piperidino, pyrrolidino, morpholino, normal alkyl group having 1 to 15 carbon atoms, t-
In addition to alkyl groups such as butyl groups, normal alkoxy groups having 1 to 15 carbon atoms, alkoxy groups such as t-butoxy groups, normal alkylthio groups having 1 to 15 carbon atoms, t-thiobutoxy groups, hydroxy groups, and mercapto groups. and halogen, etc. can be used.

Furthermore, the electron-withdrawing substituent is a nitro group where σ>0,
Cyano group, trifluoromethyl group, isocyanate group,
Sulfonyl groups, formyl groups, carboxyl groups, alkoxycarbonyl groups having an alkyl chain having 1 to 10 carbon atoms, t-butoxycarbonyl groups, acetylamino groups, halogens, and the like can be used.

Various synthetic methods can be considered as a method for producing the organic nonlinear optical material of the present invention, but the method can be preferably achieved by using a Claisen-Schmidt condensation dehydration reaction according to the following formula.

RIA-s　　　　　　　R+～.

That is, it can be obtained by carrying out a dehydration condensation reaction between the corresponding acetone or cycloalkanone and a substituted benzaldehyde derivative under a basic or acidic catalyst.

As basic catalysts, sodium hydroxide, potassium hydroxide, sodium alkoxide, various amines, and various quaternary ammonium salts can be used, and as acidic catalysts, hydrochloric acid, sulfuric acid, acetic acid, trifluoroboric acid, trifluoroboric acid, Boron fluoride etherate, etc. can be used.

The above acetone or cycloalkanone and the substituted benzaldehyde derivative are heated under reflux in the presence of the above catalyst using an alcohol such as methanol or ethanol at a temperature range of 10°C to 30°C, or as necessary, for 30 minutes. The dibenzalketone derivative of the present invention can be obtained by carrying out the reaction for a minute to an hour. Purification methods include alcohols, halogenated solvents such as ethyl acetate and chloroform,
In addition to recrystallization purification using benzene-based solvents such as toluene,
Column chromatography purification methods with appropriate solvents can be used to provide pure dibenzalketone derivatives with different crystal structures.

Examples of the dibenzalkaton derivatives used in the present invention include compounds represented by the following structural formula.

(Function) The compound used in the present invention is a dibenzalketone derivative having a widely spread π-electron conjugated structure and a moderate dipole moment, which causes intramolecular resonance at the molecular end and further changes the bulk structure. Since the molecular structure allows a non-centrosymmetric structure to be realized by introducing a molecular orientation control group, it is thought to provide extremely high nonlinear susceptibility.

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

The second harmonic generation (SHG) was measured using the second harmonic generator shown in Fig. 1 using the powder method (S, K s
KurzST%T, Perry, 39.3
798 (I968)'). The light source used for the measurement was a Nd, YAG laser, with a fundamental wavelength of 110
A powder sample was irradiated with a 64n laser beam, and the generated double wave (532nn+) was detected with a spectrometer. The powder samples used were crystals collected from the reaction, purified by recrystallization with acetone, ethyl acetate, and toluene, and used as they were.

Example 1 One part of ethanol was added to a 300111 reaction vessel equipped with a thermometer.
50- and NaOH2,3 dissolved in distilled water 15W1
Prepare 8g (59.5gM), cyclohenta/75.
Add 0g (59.5mM), cool to 5°C, and stir.

After stirring for 10 minutes, p-methoxybenzaldehyde 1
6.2 g (I19,0+eM) was gradually added dropwise. After 1 hour, the deposited precipitate was collected by filtration under reduced pressure.

The precipitate was washed 5 times with 50 d of distilled water and further washed with 50 d of ethanol.
After washing 5 times at 0 m, dry under reduced pressure and heat to obtain 11.0 g.
A crude product of the above compound Hidden 1 was obtained (92%).

This product was recrystallized using acetone, ethyl acetate, and toluene, and the product li! recognition is I('-NMR1I
I went with R.

H'-NMR (CDCTz), j, ;3.06
(4)1. S), 3.84 (68, S>, 6.95
(4Hα, J = 9), 7.53 (28, S), 7°5
5 (48, d, J = 9) TR (KBr) cm -': 3LOO ~ 2800, 1
710,1615.1520゜1270.1190.1
050,860 When the SHG intensity of the sample was measured using the above method, it was found to be 55.5 times stronger than urea (acetone).
, 50.5 (ethyl acetate), 25.0 () toluene) could be confirmed.

Example 2 An aqueous solution of 1.2 g of NaOH dissolved in 75% of ethanol and 8111% of distilled water was charged into a Nilo reaction vessel equipped with a temperature needle. To this, 2.5 g of cyclopentanone (29,
After cooling to about 5°C, 8.4 g (59.5 mM) of orthochlorobenzaldehyde was gradually added dropwise. After stirring for 30 minutes, the deposited precipitate was collected under reduced pressure, washed 5 times with 50 d of distilled water, washed 3 times with 50 ml of ethanol, and dried under heat under reduced pressure to obtain the crude product of the compound N [12]. 8.5 g (92%) was obtained.

The obtained crystals were purified by recrystallization with acetone and toluene.

The H'-NMR and III data of this compound are shown below.

H'-NMR (CDCrt), 2.99
(4H, S), 7.22-7°36 (5H, m), 7.
42-7.58(3)1, +w), 7.93(2H
,S)IR(KBr)cm-';3100-2800
．． 171O11625, 1525, 1270, 1190
, 1050, 850 SHG by the same method as in Example 1
When the intensity was measured, it was confirmed that the crystals recrystallized with acetone had no SHG activity, but the sample recrystallized with toluene had SHG activity 46.0 times that of urea.

Example 3 In the same reaction as in Example 1, 150 d of ethanol, Na
OH1.2g/HzO10id, cyclopentanone 2
．． 5g (29,8H gate), p-tolualdehyde 7.14
g (59.6mM) to prepare the crude product of compound N113 8.g (59.6mM). Og (93%) was obtained.

A precipitate from the reaction and a purified product recrystallized with ethyl acetate were prepared as samples for SHG measurement.

When the SHG intensity was measured using the same method as in Example 1, it was found that the recrystallized purified product with ethyl acetate was inactive, but the precipitate from the reaction had 54.0 times more SHG than urea.
It showed HG activity.

Example 4 Enamine 5.0 g (32,68 wM) in reaction vessel
, p-(N,N-dimethylamino)benzaldehyde 5
．． 78 g (32.68 mM) and a catalytic amount of p-)luenesulfonic acid 66.0 μl were charged. Using benzene as a reaction solvent, the mixture was heated under reflux for 12 hours. Next, an aqueous hydrochloric acid solution was added dropwise at room temperature, and the mixture was extracted three times with benzene. The benzene phase was washed twice with a 5%-NaHCOi aqueous solution and then twice with distilled water. After removing benzene under reduced pressure, the obtained crystals were recrystallized with n-hexane to obtain 7.94 g of a crude monobenzalketone derivative.

Next, the obtained monobenzalketone derivative 415■ (I,
7078mM), benzaldehyde 180■(I,
7mM), Na01 (272■(6,8mM))
0- to a reaction vessel, and a reaction was carried out using 2-butanol 5.1- as a reaction solvent. After heating under reflux for 3 hours, the mixture was poured into ice water, extracted three times with chloroform, and dried over anhydrous magnesium sulfate. After removing the solvent under reduced pressure, 230.55 g (97%) of crude crystals of the compound 23 were obtained.

H'-NMR and IR data of the obtained compound are shown below.

H'-NMR (CDCI3; 1.15 (6H, t), 3
．． 0(4H,brs)3.35(41(,q),6.6
5(2)1, d), 7.1-7.6(9)1. Seagull) TR (KBr) cm −'; 3000 to 2800,
1690, 1620. 1590°1530.1190
．． 820.770.700 Example 5 Monobenzalketone derivative 473■ (I, 947mM), which is an intermediate obtained in the same manner as in Example 4, p-methoxybenzaldehyde 272■ (2+*M), N
3201 mg (8+mM) of aOH was charged into a 50 d reaction vessel, and a reaction was carried out using 6.0 d of 2-butanol as a reaction solvent. Thereafter, the same procedure as in Example 4 was carried out to obtain 0.65 g (93%) of crude crystals of the compound N1124.

)l'-NMR1IR data of the obtained compound are shown below; H'-NMR (CDCIs); 1.1B (6H,
t), 3.0 (4H, brs), 3.15-3.60 (
48, q), 3.8 (3H, s), 6.5-7.0 (4
) 1゜m), 7.25-7.60 (68, Waku) IR (K
Br) cm −'; 3000 ~ 2800.1680
．． 1600.1580.1250.1180 Examples 6-22 The intensity ratio of 5IIG to urea of the compound obtained by reacting in the same manner as in Example 1 and Example 4 is shown in Table 1 together with Examples 1-6.

However, since the 5t(G intensity ratio differs depending on the state in which each crude product is obtained, the respective maximum values are shown.

Table 1 (Effects of the Invention) The nonlinear optical material of the present invention having the above configuration has a high melting point, low sublimation, and low water absorption, so it has excellent storage stability and has an extremely high nonlinear susceptibility. has
It is possible to provide an organic nonlinear optical material that also has excellent laser resistance. Therefore, it is effective for semiconductor laser wavelength conversion elements, laser fusion (energy storage) elements, optical pickup measuring instruments, and other optical information and optical communication elements that contribute to increasing the recording density of compact discs and the like.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a second harmonic generator used in an embodiment of the present invention. FIG. 2, FIG. 3, and FIG. 4 are infrared absorption spectra of compound levels 1 to 3. 1; Q switch 111d, YAG laser-2; 106
4n- laser mirror 3; Shutter 4; Sample 5; Condenser lens 6; Infrared cant filter 7; Polychromator 8; Multi-channel photodiode (MCPD) 9
;MCPD drive circuit 10;computer interface

Claims (1)

[Claims] 1. A nonlinear optical material characterized by containing a dibenzalketone derivative represented by the following general formula (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I
) (In the formula, x is 0 or 1, and y is an integer of 0 to 4. A and B are aromatic hydrocarbon groups with or without a substituent, and may be the same or different. )