JPH0565510B2 - - Google Patents

Description

[Detailed description of the invention]

"Industrial Application Field" The present invention relates to novel nitrobenzene derivatives. More specifically, the present invention relates to novel nitrobenzene derivatives useful as nonlinear optical materials. "Prior Art" In recent years, materials that have a nonlinear optical effect - the nonlinearity between polarization and electric field that appears when a strong optical electric field such as that of a laser beam is applied - have attracted attention. Such materials are generally known as nonlinear optical materials and are described in detail in, for example: “Nonliner Optical Properties of
Organic and Polymeric Materials”ACS
SYMPOSIUM SERIES 233, David J.
Williams (ed.) (American Chemical Society,
(published in 1983), "Organic Nonlinear Optical Materials" supervised by Masao Kato and Hachiro Nakanishi (published by CMC, published in 1985). One of the applications of nonlinear optical materials is second harmonic generation (SHG) based on second-order nonlinear effects and wavelength conversion devices using sum frequency and difference frequency.
The materials that have been practically used so far are inorganic perovskites represented by lithium niobate. However, in recent years, it has become known that π-electron conjugated organic compounds having an electron-donating group and an electron-withdrawing group have various performances as nonlinear optical materials that far exceed those of the above-mentioned inorganic materials. However, derivatives of p-nitroaniline known to exhibit high SHG, e.g.
2-Methyl-4-nitroaniline (MNA) and 2
-N,N-dimethylamino-5-nitroacetanilide (DAN) and the like have a problem of low transmittance to blue light because they are strongly colored yellow. Therefore, the emergence of nonlinear optical materials with high transmittance for blue light is desired. Conventionally, attempts have been made to replace the carbon atoms in the benzene nucleus of nitroaniline with nitrogen atoms, but satisfactory results have not always been obtained. Therefore, the present applicant has already disclosed in Japanese Patent Application No. 61-53884 (see Japanese Patent Application Laid-Open No. 62-210432) an invention relating to a novel organic nonlinear optical material having high blue light transmittance and high efficiency. However, although sufficient improvements have been made in the transmittance of blue light, the efficiency in the microcrystalline state disclosed in the above-mentioned application is still far from being sufficient. Now, the second-order nonlinear susceptibility (β) in the molecular state
is well known to be obtained by calculation using the molecular orbital method. The present invention and patent application 1986-
Regarding the compound related to No. 53884, the results of determining β using the PPP-MO method were calculated using the second method in the microcrystalline state.
Table 1 shows a comparison with p-nitroaniline, which is the basic structure of a compound with extremely high harmonic generation efficiency.

[Table] As is clear from Table 1, the present invention and patent application
The compound related to No. 61-53884 has a nonlinear susceptibility in the molecular state that is equivalent to or higher than p-nitroaniline, and is a compound that inherently has the ability to express a nonlinear optical effect with high efficiency. . The reason why nonlinear optical effects cannot be fully exerted in the microcrystalline state is that the molecular arrangement does not utilize β 100% effectively and is tilted. Therefore, somehow set β to 100%
All that is needed is to control the arrangement of the molecules so that they can be used effectively. As such methods, a method using an LB film and a method in which the LB film is dissolved in a polymer and then aligned in a certain direction using an electric field are known. However, in order to form an LB film, it is necessary to have a long-chain aliphatic group, and in order to dissolve it in a polymer, it is necessary to have high solubility, but such compounds have not been known so far. It wasn't. "Problems to be Solved by the Invention" Therefore, an object of the present invention is to provide a novel p-nitrobenzene derivative that is suitable for forming an LB film and has excellent solubility in polymers. "Means for Solving the Problems" The present inventors have discovered that the above object can be achieved by using a compound represented by the general formula (), and have accomplished the present invention. General formula () In the formula, Z represents an atomic group necessary to form an optionally substituted imidazole ring, pyrazole ring, or triazole ring. R represents a straight chain alkyl group, a branched alkyl group, and an optionally substituted phenyloxy group-substituted alkyl group having a total of 2 or more carbon atoms. The imidazole ring, pyrazole ring, and triazole ring formed by Z include alkyl groups such as methyl group and ethyl group, halogen atoms such as fluorine atom, chlorine atom, and bromine atom, and alkoxy groups such as methoxy group and ethoxy group. ,

[Formula] may be substituted with an acylamino group of the group (R' is the same as R),
Among them, methyl group and

[Formula] group is preferred. Examples of the alkyl group represented by R include ethyl group, propyl group, i-propyl group, butyl group, sec-butyl group, t-butyl group, amyl group,
i-amyl group, t-amyl group, hexyl group, 1-
Ethylpentyl group, octyl group, nonyl group, dodecyl group, pentadecyl group, heptadecyl group, heneicosyl group, phenoxymethyl group, 1-phenoxyethyl group, 1-phenoxypropyl group, 3-
Phenoxypropyl group, 2,5-di-t-amylphenoxymethyl group, 1-(2,5-di-t-amylphenoxy)ethyl group, 1-(2,5-di-
t-amylphenoxy)propyl group, 3-(2,
5-di-t-amylphenoxy)propyl group, 4
-(2,5-di-t-amylphenoxy)butyl group, 1-(2-chloro-5-t-amylphenoxy)hexyl group, 1-(2,4-di-t-amylphenoxy)amyl group, 1-( 2,4-di-t-
amylphenoxy)butyl group, 1-(3-acetylaminophenoxy)amyl group, 1-(2,4-
di-t-octylphenoxy)heptyl group, 1-
(2-chloro-4-t-octylphenoxy)amyl group, 1,1-dimethyl-1-(3-pentadecylphenoxymethyl group, 1-(4-t-octylphenoxy)propyl group etc. Among them, those having a total number of carbons of 4 or more are particularly preferable,
A branched alkyl group, a phenoxy-substituted alkyl group, and a straight-chain alkyl group having 17 or more carbon atoms are preferred. Specific examples of the compounds of the present invention are shown below.

【table】

【table】

【table】

[Route 1]

(R′=H or [Route 2]

[Formula] (X=RCOO or halogen) Examples of the base used are pyridine, triethylamine, 1,8-diazabicyclo[5,4,0]-
It may be an organic base such as 7-undecene, or an inorganic base such as potassium carbonate, sodium hydrogen carbonate, potassium t-butoxide, sodium hydride, or sodium hydroxide. As a solvent, n
- Hydrocarbons such as hexane, ethers such as tetrahydrofuran, 1,2-dimethoxyethane, amides such as N,N-dimethylformamide, N-methylpyrrolidone, sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, acetonitrile. Nitriles such as, esters such as ethyl acetate, etc. are used. Among these, amides, sulfur-containing compounds, and nitriles are preferred. Also, at the reaction temperature -
The temperature is preferably 10°C to 150°C, preferably 20°C to 10°C. Examples of representative compounds are shown below. "Example" Example 1 Synthesis of Compound 1 3,5-bis-[2-(2,4-di-t-amylphenoxy)butyroylamino]-1,2,4-
10 ml of N,N to 6.3 g of triazole, 1.3 g of 4-fluoronitrobenzene and 1.3 g of potassium carbonate
-10 ml of dimethylformamide was added and stirred for 3 hours on an oil solution heated to 100°C. After the reaction mixture was allowed to cool at room temperature, 50 ml of water was added, and the resulting solid was collected by filtration and washed with water. The solid collected by filtration was separated by column chromatography (ethyl acetate/n-hexane = 1/9 silica gel) to obtain the desired product. This is further ethyl acetate/n-hexane=
Recrystallization was performed using a 1/1 mixed solvent. Yield 5.3g (yield 71.6%) Melting point 140-142.5°C Example 2 Synthesis of compound 3 2.04g of 3-amino-1-(4-nitrophenyl)pyrazole and 0.92g of propionyl chloride
10 ml of acetonitrile was added to the solution, and 2 ml of triethylamine was added dropwise while stirring at room temperature. 60 after this
The mixture was stirred for 2 hours over an aqueous solution heated to 0.degree. C., and then allowed to cool to room temperature. 50 ml of water was added, and the precipitated crystals were collected by filtration and washed with water. The obtained coarse crystals were recrystallized from isopropanol using activated carbon. Yield 2.1g (yield 80.8%) Melting point 202-203℃ Example 3 Synthesis of compound 5 In Example 2, propionyl chloride 0.92
g for 2-(2,4-di-t-amylphenoxy)
The reaction was carried out in the same manner except that 3.39 g of butyroyl chloride was used and acetonitrile was replaced with N,N-dimethylacetamide. Purification was performed by column chromatography using silica gel and alumina (chloroform solution) to obtain the desired product. Yield 4.15g (yield 82.0%) Melting point 127.5-129.5°C Example 4 Synthesis of compound 6 In Example 3, 3.39g of 2-(2,4-di-t-amylphenoxy)butyroyl chloride was
The same operation was performed except that 3.03 g of stearoyl chloride was used to obtain the desired product. Yield: 4.0 g (yield: 85.1%) Melting point: 113.5°C to 115°C Example 5, Synthesis of Compound 7 In Example 3, 3.39 g of 2-(2,4-di-t-amylphenoxy)butyroyl chloride was
Replaced with 1.8g of 2-ethylhexanoyl chloride,
A similar operation was performed to obtain the desired product. Yield: 2.62 g (yield: 79.4%) Melting point: 98-99°C Example 6 Synthesis of Compound 9 In Example 2, 3-amino-1(4-nitrophenyl)pyrazole was -amino-1-(4
-Nitrophenyl)pyrazole, 0.92g of propionyl chloride was added to 2-(2-chloro-4-t
−Amylphenoxy)octanoyl chloride 4.30
After replacing acetonitrile with N,N-dimethylacetamide, the same reaction was carried out, and the same purification as in Example 3 was carried out to obtain the desired product. Yield 4.15g (yield 78.8%) Melting point 108-108.5℃ Example 7 Synthesis of compound 10 In Example 2, 2.04g of 3-amino-1-(4-nitrophenyl)pyrazole was converted to 5-amino-
0.92 g of propionyl chloride instead of 2.18 g of 3-methyl-1-(4-nitrophenyl)pyrazole
was replaced with 4.04 g of 2-(2,4-di-t-amylphenoxy)propionyl chloride, and acetonitrile was further replaced with N,N-dimethylacetamide.
After carrying out the same reaction, the same purification as in Example 3 was carried out to obtain the desired product. Yield 4.23g (yield 81.3%) Melting point 83-85℃ Example 8 Synthesis of compound 14 In Example 7, 4.04g of 2-(2,4-di-t-amylphenoxy)propionyl chloride was converted to 2,2-dimethylpropionyl chloride. After changing the amount to 1.64 g and carrying out the reaction in the same manner, recrystallization was performed using isopropanol to obtain the desired product. Yield 2.44g (yield 80.8%) Melting point 201.5-202°C Example 9 Synthesis of compound 16 1-(2-ethylhexanoyl)-2-(2-ethylhexanoylamino)imidazole 3.35g,
10 ml of N,N-dimethylformamide was added to 1.41 g of 4-fluoronitrobenzene and 2.76 g of potassium carbonate, and the mixture was stirred for 3 hours on an oil solution heated to 100°C. After the reaction mixture was allowed to cool to room temperature, 50 ml of water was added. This was extracted with chloroform, dried over anhydrous sodium sulfate, and then subjected to silica gel and alumina column chromatography (elution with chloroform) to obtain the desired product. Yield 1.57g (yield 47.6%) Melting point 144-145℃ Reference example 1 Solubility in acetone 0.2 mmol of each of the compounds shown in Table 2 was weighed into a test tube, 1.5 ml of acetone was added, and after heating. , and left at room temperature. The results are shown in Table 2.

Table 2 shows that the compounds of the present invention have high solubility in acetone. Reference Example 2 Compatibility with polymer 0.2 mmol and 0.4 mmol of each of the compounds shown in Table 3
Millimoles were weighed into a test tube, 50 mg of polymethyl methacrylate and 2 to 5 ml of acetone were added, heated, and then allowed to cool to room temperature. This solution was cast onto a glass substrate and the acetone was evaporated. If the solubility of the compound is high, the resulting film will be transparent.
Solubility was determined by visual inspection of transparency.

【table】

【table】

[Table] Compound B can be obtained by reacting acetylacetone and 4-nitrophenylhydrazine in the presence of an acid such as hydrochloric acid. Also, compound D
is 3,5-diamino-1-(4-nitrophenyl)
It is obtained by diazotizing 1,2,4-triazole and then heating it in concentrated hydrochloric acid. Table 3 clearly shows that the compounds of the present invention have high compatibility with polymers. Reference Example 3 Formation of LB film A monomolecular film forming apparatus manufactured by Joeys Lebre was used as a monomolecular film forming apparatus. Compound 6 is dissolved in chloroform at a concentration of 5×10 ⁻⁴ mol/to prepare a developing solution. Ultrapure water was used for the aqueous phase, and 10 ^-2 mol/disodium hydrogen phosphate was used.
, adjust the pH to 7.0 with sodium hydroxide-hydrochloric acid. The water temperature was set at 25℃, and Y was placed on a quartz glass substrate.
Three layers of film were laminated. The film thickness is estimated to be 50 to 70 Å. Reference Example 4 Measurement of dc-SHG The dc-SHG method is known as a method for determining second-order nonlinear susceptibility in a molecular state. The following measurements were performed based on the method described in the abstracts of the 4th Symposium on Optical and Electronics Organic Materials by Umegaki et al., page 50. The results are shown in Table 4.

【table】

[Table] For the compounds of the present invention, an acetone solution is used,
Its concentration was 1 mol/. Nitrobenzene was measured without solvent.

Claims (1)

[Claims] 1. Nitrobenzene derivative represented by the following general formula () General formula () In the formula, Z represents an atomic group necessary to form an optionally substituted imidazole ring, pyrazole ring, or triazole ring. R represents a straight chain alkyl group having 2 or more carbon atoms, a branched alkyl group, and an optionally substituted phenyloxy group-substituted alkyl group.