JPH07107012B2 - Novel organic compound - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel organic compound, 1,3-bis [3-methyl-4- (4-methoxyphenyl) butenyl] benzene. INDUSTRIAL APPLICABILITY The novel compound of the present invention has excellent crystallinity, a cutoff wavelength in a relatively short wavelength region, and a large SHG activity. Therefore, it is used as a nonlinear optical organic material in a wide range of fields such as optical computers and optical communication. Can be used as a light control element or the like.

<Prior Art> Non-linear optical materials cause phenomena such as frequency conversion, amplification, oscillation, and switching of laser light, and generate second harmonic (SHG), third harmonic (THG), high-speed shutter,
It can be applied to optical memories and optical arithmetic elements.

Thus, non-linear optical materials have the function of converting the optical frequency, and they can be applied to optical switches, etc. that take advantage of the property that the refractive index changes with the electric field. Has been.

Conventionally, water-soluble KH ₂ P has been mainly used as a nonlinear optical material.
O ₄ (KDP), NH ₄ H ₂ PO ₄ or water-insoluble LiNbO ₃ , KNbO ₃
Inorganic single crystal materials (dielectric crystals) have been used, but recently urea, p-nitroaniline, 2-methyl-4-nitroaniline (MNA), 4 '-(N, N'- Nonlinear optical organic materials such as dimethylamino) -4-nitrostilbene (DANS) are being developed. Polymer organic materials such as polydiacetylene and polyvinylidene fluoride are also being investigated for application to waveguides having control functions, optical ICs, etc. by utilizing their nonlinear optical effects.

Non-linear optical organic materials do not have lattice vibration with respect to optical response because the origin of non-linearity is intramolecular π-electrons, and therefore have a faster response than inorganic materials, and have a large non-linear optical constant or absorption region. It is possible to compose things that can change. Moreover, the method for forming the material element is not limited to single crystallization, and various methods such as LB film, vapor deposition method, liquid crystal, and polymerization can be considered.

Regarding the research on these nonlinear optical materials, for example, "Organic Nonlinear Optical Materials" edited by Masao Kato, Hachiro Nakanishi (CMC, published in 1985), "Nonlinear Optical Proper"
ties of Organic Molecules and Crystals Vol.I and Vo
Recent research status is summarized in the literature such as l.II DSCHEMLA, J.ZYSS edition (ACADEMIC PRESS, published in 1987).

By the way, among the nonlinear optical effects required as a nonlinear optical material, the second harmonic generation (SHG) is positioned as a basic technique of wavelength conversion because of its high conversion efficiency. In addition, a material with a large effective nonlinear optical constant is required for efficient SHG. In order for a material to exhibit optical non-linearity, it must have no spatial inversion symmetry, especially that the crystal has no symmetry center, that is, no inversion symmetry occurs in the molecular arrangement in the crystal. Is necessary for practical use.

Therefore, development of a nonlinear optical organic material that forms a single crystal having no center of symmetry and has a large effective nonlinear optical constant and therefore a large SHG activity is currently most demanded. Further, in practical use as a nonlinear optical material, it is desired to form a single crystal that is stable and has a size as large as possible at room temperature.

Further, conventionally known organic materials exhibiting a non-linear effect have a problem that the cut-off wavelength (absorption edge wavelength) of the chemical itself shifts considerably to the long wavelength side, limiting the usable wavelength range. There is. Current semiconductor laser wavelength is 800 nm
It is practically necessary that the cutoff wavelength is in the short wavelength region of 400 nm or less. In general, a nonlinear optical organic material gives a crystal focused on yellow or orange due to the structure of a π-electron conjugated system. There is. For example, p-nitroaniline
The cutoff wavelength exists in the long wavelength region such as 470 nm, 480 nm for MNA, and 430 to 580 nm for DANS. Therefore, in terms of practical requirements as an optical frequency conversion element, it is required that the material is a transparent material and therefore has a wide transparent wavelength range and a cutoff wavelength in a shorter wavelength range than the conventional one.

Conventionally known nonlinear optical inorganic materials generally have good crystallinity,
Although a large crystal can be easily obtained, a single crystal with high purity is expensive, has deliquescent properties, and has a non-linear optical constant smaller than that of an organic material. On the other hand, it is known that some nonlinear optical organic materials generally have large nonlinear optical constants, but it is difficult to prepare stable and large organic crystals at room temperature. For example, among the conventionally known organic crystals, MNA is a crystal that does not have a center of symmetry, so it has SHG activity and the second harmonic generation rate is L.
It is reported to be about 2000 times as large as iNbO ₃ . However, MNA has a drawback that it is not practical because it is difficult to obtain a large single crystal. Further, although urea is easy to obtain a large single crystal, is white and transparent, and has a short cutoff wavelength of 200 nm, it has drawbacks such as low SHG activity and poor moisture resistance. Although p-nitroaniline and DANS show a root with a very large molecular polarizability β at the molecular level,
If it becomes a crystal, it will have inversion symmetry in the molecular arrangement, so SH
There is a problem that G does not show activity.

Recently, various kinds of diolefin compounds (JP-A-61-78748), benzalacetophenone derivatives (JP-A-63-85526), N- [2- (5-nitrofrillidene)]-4 have been used as nonlinear optical organic materials. -Methoxyaniline (JP-A-63-
A compound group including new compounds has been developed.

However, it is still inadequate in providing a nonlinear optical organic material having a high SHG activity, stability, easy growth to a large single crystal, excellent transparency, and a short cutoff wavelength.

<Problems to be Solved by the Invention> An object of the present invention is to overcome the problems of the above-mentioned prior art, form a single crystal that is stable at room temperature and does not have a center of symmetry, and make a large single crystal if necessary. It is intended to provide a nonlinear optical organic material that can be grown, has a high SHG activity, is excellent in transparency, and has a cutoff wavelength in a short wavelength region.

As a result of earnest studies by the present inventors, 1,3-bis [3-methyl-4- (4-methoxyphenyl) butenyl] benzene, which is a novel organic compound, is a stable and good crystalline compound, and SHG It was found that a highly active transparent organic crystal was formed and the cutoff wavelength was in the relatively short wavelength region of 398 nm, and the present invention was completed based on this finding.

<Means for Solving the Problems> That is, according to the present invention, the following chemical formula There is provided 1,3-bis [3-methyl-4- (4-methoxyphenyl) butenyl] benzene represented by

This compound can be suitably used as a nonlinear organic material.

Hereinafter, the components of the present invention will be described in detail.

The compound used in the present invention, 1,3-bis [3-methyl-4-
(4-Methoxyphenyl) butenyl] benzene represents two 3-methyl-4- (4-
The methoxyphenyl) butenyl group has a structure in which it is bonded to benzene, which is the center of the π-electron conjugated chain, in the meta position, but the symmetry of the crystal is broken due to the bond in the meta position. It is presumed that the SHG activity was expressed because the polarization due to the methoxy group remained.

As a method for synthesizing 1,3-bis [3-methyl-4- (4-methoxyphenyl) butenyl] benzene, for example, 1 mol of α, α′-dibromo-m-xylyltriphenylphosphonium bromide and p-methoxy can be used. There is a method of reacting 2 mol of -α-methylcinnamaldehyde in a dimethylformamide solvent in an inert atmosphere by adding sodium methoxide dropwise.

1,3-Bis [3-methyl-4- (4-methoxyphenyl) butenyl] benzene has good crystallinity, and a single crystal can be easily obtained from an organic solvent by a slow evaporation method or the like. The single crystal is stable at room temperature,
It is less susceptible to optical damage and can be easily processed into devices because it is easy to process.

And the 1,3-bis [3-methyl-4- (4-
A single crystal of methoxyphenyl) butenyl] benzene and a fine powder of the crystal show an excellent non-linear optical effect, as is clear from the fact that the SHG efficiency is about 2.5 times that of urea.

Further, the 1,3-bis [3-methyl-4- (4-methoxyphenyl) butenyl] benzene of the present invention is as white and excellent in transparency as urea, and its cutoff wavelength is 398 nm, which is a relatively short wavelength. Therefore, it can be used as a wavelength conversion element for a semiconductor laser of about 800 nm. The compound of the present invention can be used as a nonlinear optical material in various forms such as powder, single crystal, and solution.

Further, the novel organic compound of the present invention may be used as a whitening agent, a laser dye or the like in view of its structure.

<Examples> Hereinafter, the present invention will be specifically described with reference to Examples, but it goes without saying that the present invention is not limited to these Examples.

Example 1 10.0 g (38 mmol) of triphenylphosphine and α, α′-
About 5.0 ml (19 mmol) of dibromo-m-xylene was added with about 40 ml of xylene and dissolved. A white phosphonium salt precipitates when the solution is refluxed for about 4 hours. The precipitate was filtered, the filtered product was washed with xylene, and then vacuum dried. When this white powder was recrystallized with a mixed solvent of methanol-ether, 7.5 g of α, α'-dibromo-m-xylyltriphenylphosphonium bromide was obtained.

3.94 g (5 mmo of α, α'-dibromo-m-xylyltriphenylphosphonium bromide thus obtained)
l) and p-methoxy-α-methylcinnamaldehyde 1.7
After adding 20 ml of dried dimethylformamide to 6 g (10 mmol) to make a solution, 12 ml of 1.09 N sodium methoxide is slowly added dropwise under a stream of argon.

The solution is stirred at room temperature for 4 hours under an argon atmosphere, then concentrated and an appropriate amount of ethanol is added. The precipitate was filtered and washed with alcohol to obtain the target compound 1,3-bis [3-methyl-4- (4-methoxyphenyl) butenyl] benzene. The yield was 0.81 g.

Next, the results of measuring IR, ¹ H-NMR, UV and melting point of the product are shown below.

UV (CHCl ₃ ): λ _max = 331 nm, λ _cutoff = 398 nm Melting point: 200 ° C. IR and ¹ H-NMR spectra and assignments are shown in Table 1.

The IR spectrum is shown in FIG. 1 and the ¹ H-NMR spectrum is shown in FIG.

From the above measurement results, it was clarified that the obtained compound was 1,3-bis [3-methyl-4- (4-methoxyphenyl) butenyl] benzene having the above chemical formula. Further, when a fine powder crystal of the obtained compound is irradiated with an Nd: YAG laser (wavelength = 1.064 μm, output 10 mJ / pulse),
The second harmonic is generated (SHG), and half the wavelength of the incident light (532n
m) green light was observed. In addition, SHG efficiency is 2.
It was 5 times.

The results are stable at room temperature, good crystallinity, and excellent transparency.

<Effects of the Invention> The novel compound of the present invention is stable and crystallizable at room temperature, has a large SHG activity, is excellent in transparency, and has a cutoff wavelength in a short wavelength region. It is also useful as a wavelength conversion element of a semiconductor laser and has important practical significance.

[Brief description of drawings]

FIG. 1 is a diagram showing an IR spectrum of 1,3-bis [3-methyl-4- (4-methoxyphenyl) butenyl] benzene, and FIG. 2 is a diagram showing a ¹ H-NMR spectrum. .

Claims (2)

[Claims] 1. The following chemical formula 1,3-bis [3-methyl-4- (4-methoxyphenyl) butenyl] benzene represented by: 2. A nonlinear optical organic material comprising the compound according to claim 1.