JPH0356449A - 1-(4-methoxystyryl)-3-(4-nitrostyryl)benzene and production thereof - Google Patents

Abstract

NEW MATERIAL:The compound of formula I. USE:Useful as a non-linear optical material, fluorescent brightener, laser dye, etc. It has various characteristics such as stability at room temperature, high crystalinity, SHG activity and transparency and short peak wavelength. PREPARATION:The compound of formula I can be produced by reacting P- nitrophenylacetic acid of formula II with isophthalaldehyde of formula III in a polar solvent (e.g. DMF or methanol) in the presence of a basic catalyst (e.g. pyridine or ammonium acetate) and reacting the resultant 3-[2-(4- nitrophenyl)ethenyl]-benzaldehyde of formula IV with p-methoxybenzyl triphenyl phosphonium halide of formula V in the presence of an organic base.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a novel organic compound, 1-(4-methoxystyryl)-3-(4-nitrostyryl)benzene, and a method for producing the same. The novel compounds of the present invention are particularly useful as nonlinear optical materials, and can also be applied to applications such as fluorescent brighteners and laser dyes.

[Conventional technology]

Nonlinear optical materials produce phenomena such as frequency conversion, amplification, oscillation, and switching of laser light, and generate second harmonics (
Applications include S}IG), third harmonic generation (THG), high-speed shutters, optical memories, and optical arithmetic elements. In addition, nonlinear optical materials can be applied to optical switches that take advantage of the property that their refractive index changes depending on the electric field. Conventionally, KH. PO4, N
H4 H! PO4, LiNbOa, KNbO*
Inorganic single crystal materials such as urea, p-nitroaniline, 2-methyl-4-nitroaniline (MNA), 4-(N,N-dimethylamino)-4'- Development of nonlinear optical organic materials such as nitrostilbene (DANS) and stilbazolium salts is progressing. Nonlinear optical organic materials generally have nonlinearity originating from intramolecular π electrons, so they do not involve lattice vibration in response to light, and therefore have faster response than inorganic materials, and they also have large nonlinear optical constants. It is possible to synthesize materials whose absorption region can be changed. Furthermore, the method of making materials into devices is not limited to single crystallization;
Various methods can be considered, such as , vapor deposition, liquid crystallization, and polymerization. By the way, nonlinear optical materials are required to have the following properties. (1) Among nonlinear optical effects, especially second harmonic generation (S
HG) is positioned as a basic technology for wavelength conversion due to its high conversion efficiency, and SHG efficiency (1
) is required to be high. (2) For a material to exhibit optical nonlinearity, it must not have spatial inversion symmetry, and in particular, its crystal must not have a center of symmetry. (3) It is desired that the material be stable at room temperature and form a single crystal as large as possible. (4) The wavelength of current semiconductor lasers is about 800 nm, so the maximum wavelength (Lmax) and cutoff wavelength (λ
It is practically preferable that the wavelength (cutoff) be in the short wavelength region as much as possible. However, known nonlinear optical inorganic materials are expensive to produce single crystals with high purity, have deliquescent properties, and are generally SHG-based.
It has the disadvantage of low efficiency. On the other hand, it is known that some nonlinear optical organic materials have high SHG efficiency at 1M, but it is difficult to prepare stable and large crystals at room temperature. For example, MNA
Although it has high SHG efficiency, it is difficult to obtain large single crystals. Urea is easy to obtain large single crystals and has a white color.
Although it is transparent and has a short cutoff wavelength of 200 nm, it has the disadvantage of poor moisture resistance. In addition, DANS, a stilbene derivative, exhibits a very large second-order nonlinear polarizability β at the molecular level, but when crystallized, it exhibits no nonlinear optical effect because the molecular arrangement has inversion symmetry. Thus, there is a need for nonlinear optical materials that have high SHG efficiency, are stable, are easy to grow into large single crystals, and have excellent transparency, but materials with sufficient performance have not yet been provided.

[Problem to be solved by the invention]

An object of the present invention is to provide a novel organic compound. Another object of the present invention is to provide a novel organic compound having a nonlinear optical effect. Furthermore, it is an object of the present invention to overcome the problems of the prior art, to form a single crystal that is stable at room temperature, has no center of symmetry, and can be grown into a large single crystal if necessary, and to The objective is to provide a nonlinear optical material with high activity and excellent transparency. As a result of intensive research, the present inventors found that 1-(4-methoxystyryl)-3-(4-nitrostyryl)benzene, a new organic compound, is a stable and crystalline compound, and has a high SHG activity. form large transparent organic crystals of
It was also found that the maximum wavelength was 330 nm, which was in the short wavelength region. This compound is also known as Knoevenagel (Knoev).
It has been found that synthesis can be carried out by sequentially performing a combination of enagel condensation and Wittig reaction. It has been discovered that this compound is useful as a nonlinear optical material, but also has the potential to be used as a fluorescent whitening agent, laser dye, etc. The present invention has been completed based on these findings. [Means for solving the problem 1 That is, according to the present invention, 1 represented by the following formula [I]
-(4-methoxystyryl)-3-(4-nitrostyryl)benzene is provided. Further, according to the present invention, p-nitrophenylacetic acid and isophthalaldehyde are condensed to synthesize 3-[2-(4-nitrophenyl)ethenyl]benzaldehyde, and then the 3-(2-(4- nitrophenyl)ethenyl]
pen. 1-(4-methoxystyryl)-3-, which is characterized by reacting zaldehyde and p-methoxybenzyltriphenylphosphonium halide in the presence of a base.
A method for producing (4-nitrostyryl)benzene is provided. This compound can be particularly suitably used as a nonlinear optical material. Hereinafter, the constituent elements of the present invention will be explained in detail. [1-(4-methoxystyryl)-3-(4-nitrostyryl)benzene] 1-(4-methoxystyryl)-3-(4-nitrostyryl)benzene of the present invention is a new chemical substance. Since the compound of the present invention has no center of symmetry,
It shows excellent nonlinear optical effects, and the SHG efficiency of microcrystalline powder is comparable to that of urea. Moreover, λa+ of the compound of the present invention
ax is 330 nm% Lcutoff is 446n
m, which is in a relatively short wavelength region. The compound of the present invention has a structure in which two styryl groups each having a methoxy group or a nitro group bonded to the side chain are bonded to the meta position of benzene, which is the center of the π-electron conjugated chain. It is presumed that due to such a structure, the symmetry of the crystal is disrupted and, at the same time, SHG activity is expressed due to polarization due to the methoxy and nitro groups. The compound of the present invention has stable crystals at room temperature, excellent resistance to light damage, and, like urea, excellent white transparency. As is clear from its chemical structure, it is also suitable for applications such as fluorescence brightening agents and laser dyes that utilize fluorescence. In addition, 1-(4-methoxystyryl)-3-( of the present invention
4-nitrostyryl)benzene has good crystallinity, and a stable single crystal at room temperature can be obtained by slow evaporation or the like. (Production method) Until now, a method for producing a 1,4-distyrylbenzene derivative represented by the general formula [II] ([1) has been known (CAMPBELL AND McD
ONALDJ. Org. Chm. , 24. 1
246 (1959)). In this synthesis method, a distyrylbenzene derivative is obtained in one step using a bisphosphonium salt or terephthalaldehyde as a starting material. However, with this known method, it is not possible to introduce different functional groups into each styryl group. Therefore, as a result of extensive research in order to synthesize this type of asymmetric distyrylbenzene derivative, the present inventors succeeded in carrying out a continuous combination of Knoevenagel condensation and Wittig reaction. It was discovered that a compound represented by the above formula [I] can be synthesized. That is, in the present invention, first, Q, 3-[2
- Synthesizing (4-nitrophenyl)ethenyl]benzaldehyde (Knoevenagel condensation). This condensation reaction is carried out in a polar solvent such as dimethylformamide (DMF), methanol, or acetic acid using a base such as biperidine, an alkylamine, or ammonium acetate as a catalyst. Next, the target compound 1- is obtained by reacting the 3-[2-(4-nitrophenyl)ethenyl]benzaldehyde obtained above with p-methoxybenzyltriphenylphosphonium halide in the presence of an organic base.
(4-methoxystyryl)-3-(4-nitrostyryl)benzene is produced (Wittig reaction). Examples of the p-methoxybenzyltriphenylphosphonium halide include p-methoxybenzyltriphenylphosphonium chloride and p-methoxybenzyltriphenylphosphonium bromide. (Left below) This reaction is carried out under basic conditions using, for example, an organic solvent such as DMF, methanol, or ethanol as a solvent. Examples of the base include sodium methoxide, sodium ethoxide, lithium methoxide, phenyllithium, sodium amide, potassium hydroxide,
Sodium hydroxide, butyl lithium, etc. are used, and the reaction temperature is usually in the range of 20 to 80°C.

【Example〕

The present invention will be specifically described below with reference to Examples, but the present invention is not limited only to these Examples. [Example 1] (1) Synthesis example of 3-[2-(4-nitrophenyl)ethenyl]benzaldehyde 2.72 g (15 mmol) of p-nitrophenylacetic acid and 6.03 g (45 mmol) of isophthalaldehyde were added to 50 mj2 of After dissolving in DMF, add a few drops of viveridine, raise the temperature to 100°C, and allow to react for 2 hours. After the reaction is complete, add 150 mj2 of 1N hydrochloric acid. Dry the chloroform layer over anhydrous sodium sulfate, and evaporate the solvent. When distilled water is added to the resulting oily substance, a precipitate forms. This was filtered and dried to obtain 2.5 g of a crude product.
The crude product was recrystallized from chloroform-methanol to obtain the target compound (1.44 g, yield 57%).
．． 'H-NMR spectrum of this compound (see Figure 3)
As a result of analysis, 3-[2- (4-nitrophenyl)
It was confirmed to be ethenyl]benzaldehyde. (2) Synthesis example of p-methoxybenzyltriphenylphosphonium chloride 26.3 g (0.1 mmo!) of triphenylphosphine and 15.7 g (0.1 mol) of p-methoxybenzyl chloride were mixed in 150 mQ of benzene. and refluxed for 4 hours. After cooling, the mixture was filtered and the precipitate was washed several times with benzene. This was recrystallized from a chloroform-petroleum ether mixed solvent to obtain the desired product (20
g, yield 48%). (3) Synthesis example of l-(4-methoxystyryl)-3-(4-nitrostyryl)benzene 3-(2-(4-nitrophenyl)ethenyl)benzaldehyde obtained in the above synthesis example (1) 1. 26g
(5 mmol) and 2.10 g of p-methoxybenzyltriphenylphosphonium chloride obtained in Synthesis Example (2)
(5 mmol) was dissolved in 20+nJ2 of anhydrous DMF. Add 0.4 g (7 m
mol) of sodium methoxide in methanol (2
0 mI2) was slowly added dropwise, and the reaction was allowed to proceed for 3 hours. After the reaction was completed, the solution was concentrated and methanol was added to form a precipitate. Filtration was performed and the filtered material was washed several times with methanol (yield: 380 mg, yield: 21%). Next, the results of measuring the ■R, 'H-NMR, UVg, and melting point of the product are shown below. Melting point: 178°C IR: 2850 (Ar-OCHs). 1
600 (C:C), 1520 (Ar-H). 1340(
Ar-NOx), 1180, 1120. 1040(
=C-0-C) [carL]'H-NMR: 3.84 (S, 3H).
6.92 (d, J=.8.8, 2H) (CDCjs)
6. 99 (d, J=16.2, IH)
，'! ．． 12 (d, J=16.4, IH), 7.
17 (d, J=16.3, IH), 7. 28(d
, J=16.2. 18) ,7. 3-7. 5(
m, 3H), 7. 47 (d, .CL 8,
2H), 7. 64 (d, J=8.8, 2H
), 7. 64 (s, 2H). 8. 22
(d, J=8.8,2H) [δ(ppm)] UV absorption: max=330 nm, (CH(Js
) λcutoff = 4 4 6 nm Also, the IR spectrum of this compound is shown in Figure 1, 'H-
The NMR spectrum and assignment are shown in FIG. From these analysis results, it was confirmed that this compound was 1-(4-methoxystyryl)-3-(4-nitrostyryl)benzene. [Example 2] The obtained fine powder crystals of l-(4-methoxystyryl)-3-(4-nitrostyryl)benzene were mixed with Nd: YA.
When irradiated with G laser (wavelength = 1.064 μm, output 10 mJ/pulse), second harmonics are generated (SHG) L
, green light with half the wavelength (5 3 2 nm) of the incident light was observed. It was also confirmed that its strength (SHG efficiency) was comparable to that of urea. It was also revealed that this crystal is stable at room temperature and has excellent resistance to light damage. The above facts indicate that this compound is an excellent nonlinear optical material. [Effect of the invention] The novel compound of the present invention is stable at room temperature and has good crystallinity.
It has high SHG activity, excellent transparency, and low λwax, so it is particularly useful as a nonlinear optical material.
It has important practical significance as a wavelength conversion element for semiconductor lasers.

[Brief explanation of drawings]

Figure 1 shows the 1-(4-methoxystyryl)-3 of the present invention.
FIG. 2 shows the IR spectrum of -(4-nitrostyryl)benzene, and FIG. 2 shows the same <'H-NMR spectrum. Figure 3 shows 3- [2- (4
-nitrophenyl)ethenyl]'H of benzaldehyde
- It is a figure showing an NMR spectrum.

Claims (3)

[Claims] (1) 1-(4-methoxystyryl)-3-(4-
Nitrostyryl) benzene. (2) A nonlinear optical material comprising the compound according to claim 1. (3) Synthesize 3-[2-(4-nitrophenyl)ethenyl]benzaldehyde by condensing p-nitrophenylacetic acid and isophthalaldehyde, and then synthesize 3-[2-(4-nitrophenyl)ethenyl]benzaldehyde.
-(4-nitrophenyl)ethenyl]benzaldehyde and p-methoxybenzyltriphenylphosphonium halide in the presence of a base 1
A method for producing -(4-methoxystyryl)-3-(4-nitrostyryl)benzene.