JPH0572582A - Nonlinear optical material - Google Patents

Abstract

PURPOSE:To obtain an org. compd. having large nonlinear optical susceptibility and excellent transparency and workability by incorporating a 1,3-diketone deriv. CONSTITUTION:In a pi electron conjugated compd. having a 1,3-diketone skeleton, nitrogen in a pyridine ring is replaced by pyridinium salt (ionic property is given). Namely, a 1,3-diketone deriv. expressed by formula I is incorporated. In formula I, R<a> is a group selected from amino groups, substd. amino groups with substituent of 1-12 carbon number, cyclic amino groups, alkyl groups, alkyloxy groups of 1-12 carbon number, nitro groups, and cyano groups. S is an integer 1-5, substituent P is a pyridinium base expressed by formula II, in which org. substituents may be substituted except for the position of N. In formula II, Rb is an alkyl group or halogen-substd. alkyl group of 1-15 carbon number, and counteranion X is halogen (fluorine, bromine, chlorine, iodine) PF6, SbF6, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonlinear optical material used for optical information, optical communication and the like, and more specifically to a nonlinear optical material composed of a 1,3-diketone derivative. For example, it can be used for a semiconductor laser circumferential wavelength conversion element, a measuring instrument, information transmission by an optical fiber, and the like.

[0002]

2. Description of the Related Art Since laser light has monochromaticity and directivity, that is, coherence, it exerts a specific interaction with a substance. This interaction is known as a nonlinear optical material effect, and causes phenomena such as harmonic generation Kerr effect, light mixing, and parametric amplification. In particular, the second-order and third-order nonlinear optical material effects can be expected to have a relatively large nonlinear susceptibility, so that they can be applied to information processing, optical communication and the like.

Conventionally, KDP (KH) has been used as a nonlinear optical material.
₂ PO ₄ ), ADP (NH ₄ H ₃ PO ₄ ), Li Nb O
Inorganic materials such as ₃ have been used and have been applied to some measuring instruments. However, it is difficult to obtain a single crystal with high purity, it is expensive, it is inferior in the light damage resistance, it is deliquescent, and the nonlinear optical susceptibility is small. .. In recent years, since it has been found that an organic material has an excellent nonlinear optical effect as compared with an inorganic material, an organic material having a high degree of freedom in terms of molecular design has attracted attention. In particular, π electrons represented by 2-methyl-4-nitroaniline are conjugated, and an electron-donating substituent and an electron-withdrawing substituent are CT (Charge-Charge-) in the molecule.
It has been considered that a large non-linear optical susceptibility can be expected because the (Transfer) type organic compound induces a large molecular hyperpolarizability.

However, the crystal structure of an organic compound is determined by intermolecular forces such as intermolecular interactions such as hydrogen bonding and van der Waals interactions. In the case of a C-T type molecule having a strong electron-withdrawing substituent and an electron-donating substituent as described above, a strong dipole-dipole interaction between molecules works to stabilize the crystal, that is, a bimolecular structure. It is easy to have a crystal structure that cancels out the dipoles. Such a crystal structure is a centrosymmetric crystal as a molecular assembly and is therefore non-linearly optically inactive.

Therefore, the following method is used as a means for breaking the central symmetry of such a crystal structure. That is, a substituent having a large hydrogen bond capable of controlling the molecular orientation of a hydroxyl group, a carboxyl group, an amino group, etc., a bulky substituent capable of greatly changing the molecular structure due to steric hindrance, and an optical activity of an amino acid or an amino acid derivative. Other substituents (D or L form),
A method of inducing non-centrosymmetry by complexing with a packaging compound such as a body is being implemented.

As a condition that the second-order nonlinear optical material can be applied as a nonlinear optical element, the nonlinear optical susceptibility is extremely large. High light response speed, excellent laser light transmission, light damage resistance, phase matching, excellent mechanical strength, easy processing, chemical resistance such as moisture resistance It must be stable, difficult to sublimate, and crystalline.

[0007]

A C-T type compound such as NPP and π-electron conjugation having a large hyperpolarizability and lacking centrosymmetry achieved by introducing a hydrogen-bonding substituent and an optically active substituent. In the case of a long molecule, a large second-order nonlinear optical susceptibility can be expected, but it has a defect such as lack of transparency. In the case of such a π-electron conjugated compound, the intermolecular bonding force is extremely brittle and difficult to process when used as a bulk crystal due to the Van der Waal force.

[0008]

The present invention has been made to solve the above problems, and provides an organic compound having a large nonlinear optical susceptibility, excellent transparency and processability. To do.

In order to achieve the above object, the present invention has the following constitution. That is, the present invention comprises a non-linear optical material containing a 1,3-diketone derivative represented by the following general formula 3.

[Chemical 3] (In the formula, R ^a may be different or the same, and an amino group, a substituted amino group substituted with a group having 1 to 12 carbon atoms, a cyclic amino group, an alkyl group, a halogen-substituted alkyl group, an alkoxy group, a mercaptoalkoxy group, It is a group selected from a halogen, a carboxyl group, an alkoxycarbonyl group, an alkanoyloxy group having 1 to 12 carbon atoms, a nitro group, a cyano group, an alkanoylamide group, a trifluoromethyl group and a sulfonyl group, and S is the number thereof. 1 to 5. Substituent P is a pyridinium base represented by Chemical Formula 4 below, and an organic substituent may be substituted at a position other than N.)

[0010]

[Chemical 4] (In the formula 4, R ^b is an alkyl group having 1 to 15 carbon atoms, the alkyl group having a halogen substitution, the substituted amino group or the alkyl group having a hydroxyl group, an aromatic methyl group, an aromatic carbonyl group, an aromatic carbonyl group. The counter anion X is halogen (fluorine, bromine, chlorine, iodine), PF ₆ , Sb F ₆ , As F ₆ , BF ₄ ,
CIO ₄ , IO ₃ , CH ₃ COO, CF ₃ COO, C ₂
F ₅ COO, a benzoic acid residue or a benzenesulfonic acid residue (the aromatic nucleus may have a substituent). )

The 1,3-diketone derivative of the present invention is in a keto-type and enol-type equilibrium state, and is largely biased to the enol-type in a solution state and a solid state. The intramolecular enolic hydroxyl group and the counter anion X have characteristics as a functional organic substituent (orientation control) capable of inducing a non-centrosymmetric structure which is a sufficient condition for SHG activity in the crystalline state, and particularly the latter Has the function of a chiral handle that can induce a non-centrosymmetric structure. Further, since the molecule has an electron-donating group and an electron-withdrawing group, the non-linearity can be increased. In particular, introduction of an electron-donating group at the ortho or para position of the aromatic ring is effective because the charge transfer interaction is increased.

In the present invention, in addition to the organic substituents of R ^a and R ^b , other substituents may be appropriately introduced as needed for fine adjustment of the performance of the compound of the present invention. As the substituent R ^{a referred to} in the present invention, amino as an electron donating group,
Amino groups such as monomethylamino, monoethalamino, diethylamino, n-butylamino and t-butylamino groups, cyclic amino groups such as piperidino, pyrrolidino and morpholino, normal alkyl groups having 1 to 12 carbon atoms, t-
A branched alkyl group such as a butyl group, an alkyl group containing an optically active carbon, a normal alkoxy group having 1 to 12 carbon atoms,
a branched alkoxy group such as t-butoxy group, an alkoxy group containing an optically active carbon, a mercaptoalkoxy group having 1 to 12 carbon atoms, a branched mercaptoalkoxy group such as a t-mercaptooxy group, and a mercaptoalkoxy group containing an optically active carbon. Besides, a hydroxy group, a mercaptohydroxy group and a halogen can be used, and as an electron-withdrawing group, a nitro group, a cyano group, a trifluoromethyl group, an isocyanate group, a sulfonyl group, a carboxyl group, a carboxylic ester acid, an acetylamino group. , And halogen can be used.

The substituent R ^{b referred to in the} present invention has 1 carbon atom.
To a branched alkyl group such as isopropyl and t-butyl, a substituent having an ether bond such as a methoxymethyl group, an alkyl group having a halogen of 1 to 15 carbon atoms, and a substituted alkyl group having a carbon number of 1 to 1 15 alkyl group, C1-C15 alkyl group having a monocarboxyl group or a dicarboxyl group at the terminal, C1-1
An organic group represented by an acyl group having 5 carbon atoms, a formic acid alkyl ester group having 1 to 15 carbon atoms, a formic acid aromatic ester group having an organic substituent, an aromatic carbonyl group having an organic substituent, and a 4-methoxybenzyl group. An aromatic methyl group having a substituent and an aromatic carbonylmethyl group having an organic substituent represented by a 4-methoxyphenacyl group can be used.

The aromatic group referred to in the present invention is a benzene ring, naphthalene ring, anthracene ring, biphenyl ring, terphenyl ring, furan ring, thiophene ring, pyrrole ring, pyridine ring, pyrimidine ring, pyrazine ring, pyridazine ring, triazine. A ring and a tetrazine ring.

As a method for synthesizing the organic nonlinear optical material of the present invention, there is, for example, the following chemical formula 5.

[Chemical 5] In the formula, R represents lower alkyl, Ac represents an acetyl group, and M represents a metal atom. In the formula, the counter anion X in the structure [A] is halogen, and the counter anion Y in the structure [B] obtained by the exchange reaction is a residue of an inorganic salt or an organic salt.

That is, in the chemical formula 5, (a) a condensation reaction between an acetophenone derivative and a carboxylic acid ester derivative,
(B) quaternization process such as N-alkylation and acylation,
(C) It can be synthesized by an exchange reaction process with various inorganic salts or organic salts. Of the compounds of the present invention represented by the general formula 1, the bond of the pyridinium group is represented by the following chemical formula 8
Indicate. A bond in the m-position is preferred.

[0017]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The second harmonic generation (SHG) is measured by the powder method (SK Kurz, TT Perry, 39, 37).
98 (1968)). The light source used for the measurement was an Nd; YAG laser, and the fundamental wavelength was 1064 nm.
Of the second harmonic wave (5
32 nm) was detected by a spectroscope. The powder sample used was recrystallized and purified with methanol or ethanol.

Example 1 Step (a) 500 ml of previously prepared anhydrous Monoglyce was poured into a 1000 ml three-necked flask under a nitrogen stream. Then, 17.5 g of purified and dried NaH (72
9.18 mM) was added to form a suspension. The temperature of the solution is 10
The temperature was adjusted to 0 ° C., and 54.7 g (364.67 mM) of Monomethoxy of 4-methoxyacetophenone was added using a dropping funnel.
me solution and 50 g of nicotinic acid methyl ester (36
(4.59 mM) Monoglyce solution was added dropwise at the same time (30 minutes). After reacting for 4 hours under heating under reflux, the mixture was poured into ice water. Stir vigorously, add concentrated hydrochloric acid dropwise, and adjust to pH 1
And Precipitated pale yellow crystals were collected under reduced pressure and distilled water 5
The solution was washed three times with 00 ml and purified by recrystallization with methanol to obtain 91 g of pale yellow crystals (yield 98%). The product was confirmed using a nuclear magnetic resonance spectrum and an infrared absorption spectrum.

Step (b) 1.0 g of the 1,3-diketone derivative obtained in step (a)
(3.9215 nM) to a 50 ml three-necked flask,
20 ml of isopropyl alcohol was poured in and dissolved by heating. After heating to reflux, 20 ml of ethyl iodide was added dropwise with a dropping funnel. After 2 hours, the mixture was returned to room temperature, cooled with ice, and the precipitated pale yellow crystals were collected under vigorous pressure and washed twice with 20 ml of ice-cooled isopropyl alcohol. The obtained crude crystals were recrystallized from ethanol to give 1.45 g of pale yellow crystals (yield 9
0%). Confirmation of the obtained N-ethylpyridinium salt derivative (Chemical formula 6 below) was performed using a nuclear magnetic resonance spectrum and an infrared absorption spectrum. The obtained N-ethylpyridinium salt derivative (Compound No. 1) was treated with SH by the above method.
When the G intensity was measured, it was possible to confirm the occurrence of SHG of 30.7 for urea.

[Chemical 6]

Step (c) 0.5 g (1.2228 mM) of the NN-ethylpyridinium salt derivative obtained in step (b) was dissolved in a mixed solvent of 5 ml of EtOH / 25 ml of distilled water with heating. 5 ml of an aqueous solution of 0.25 g (1.345 mM) of KPF ₆ was added to this solution.
Was dripped. After heating under reflux for 2 hours, the reaction solution was ice-cooled and the precipitated pale yellow crystals were collected under reduced pressure and purified by recrystallization with methanol to give N-ethylpyridinium PF ₆ salt derivative of pale yellow needle crystals (Compound No. 2). 0.4 (yield 76%) was obtained (Chemical formula 7 below). The compound was identified by using nuclear magnetic resonance spectrum, infrared absorption spectrum and elemental analysis.

[Chemical 7] When the SNG intensity of the obtained NN-ethylpyridinium PF6 salt derivative was measured by the above method, SHG of urea was 48.8 (second harmonic generation intensity ratio).
We were able to confirm the occurrence.

Examples 3 to 30 Examples 3 to 30 were carried out according to Example 1. The measured SHG value (second high frequency generation intensity ratio) is shown in Table 1 below. Tables 5 to 10 show the respective compound Nos. 3 to 30. In Table 1, the value of the urea powder is 1.0 in the second harmonic generation intensity ratio column. Less than,
The same applies to Tables 2 to 4. In Table 5, (m) in the (-P) column represents the skeleton of the following chemical formula 8,
(P) represents the skeleton of Chemical formula 9. (Hereafter, Table 6
~ The same applies to Table 10. ), In the R ^b column, it is indicated by a linkage of −, for example, in Compound No. 18, (CH ₂ CH ₂ CH ₂ Br) indicates a linkage of hydrocarbon such as (CH ₂ CH ₂ CH ₂ Br). Is. For example, compound No. 1
R ^b of 3 is-(CH ₂ CH (Cl) CH (CH ₃ ) CH
₂ CH ₃ ).

[Chemical 8]

[0022]

[Chemical 9] The numbers on the benzene nucleus and the pyridine nucleus in Chemical formulas 8 and 9 indicate the bonding position of the substituent.

Example 31 Example 1-Pyridyl-1,3 synthesized in step (a)
2.0 g (7.8431 mM) of the propanedione derivative was added to a 300 ml three-necked flask, and 100 ml of isopropyl alcohol was added and dissolved by heating. Then, 2-methoxy-5 dissolved in 20 ml of isopropyl alcohol.
2.12 g of nitro-benzyl bromide (8.6274)
(mM) was added dropwise with heating under reflux. After completion of the reaction (3 hours),
The reaction solution was cooled to room temperature and further cooled with ice. The precipitated pale yellow crystals were separated under reduced pressure under a nitrogen atmosphere and washed twice with 20 ml of cooled isopropyl alcohol. The obtained crude crystals were purified by recrystallization with isopropyl alcohol to obtain 3.23 g (yield 82%) of pale yellow needle crystals (Compound No. 3).
1). The compound was identified by using nuclear magnetic resonance spectrum, infrared absorption spectrum and elemental analysis. Obtained N-
When the SHG intensity of the (2-methoxy-5-nitro-benzyl) pyridinium Br salt derivative was measured by the above-mentioned method, generation of 11.6 SHG with respect to urea could be confirmed.

Examples 32 to 53 Examples 32 to 53 were carried out according to Example 31. The measured SHG values are shown in Table 2. (Compound No. 3
2-53).

Example 54 Example 1-Pyridyl-1,3 synthesized in step (a)
-Propanedione derivative 2.0 g (7.8431 mM)
Was added to a 300 ml three-necked flask, and anhydrous THF solution 10
0 ml was added and dissolved by heating. Then, 1.47 g (8.6274 mM) of 4-methoxybenzoyl chloride was added dropwise with a dropping funnel. After completion of the reaction (1 hour), the reaction solution was cooled with dry ice (refrigerant ethanol) to obtain 2.86 g (86%) of pale yellow crystals deposited (Compound No. 5
4). The compound was identified by using nuclear magnetic resonance spectrum, infrared absorption spectrum and elemental analysis. Obtained N-
(4-Methoxybenzoyl) pyridinium Cl salt derivative
When the SHG intensity of No. 54 was measured by the above method, generation of SHG of 11.9 with respect to urea could be confirmed. Examples 55-75 Examples 55-75 were carried out according to Example 54. Table 3 shows the measured SHG values. (Compound No. 5
5-75).

Example 76 Example 1-Pyridyl-1,3 synthesized in step (a)
-Propanedione derivative 2.0 g (7.8431 mM)
Was added to a 300 ml three-necked flask and dissolved in anhydrous THF. Under a nitrogen stream, a solution of 4-methoxyphenacyl bromide (1.98 g, 8.6274 mM) in anhydrous THF was added dropwise to the above solution. After the reaction was completed, the precipitated pale yellow crystals were collected under reduced pressure. The obtained crude crystals were purified by recrystallization twice with EtOH to obtain 3.2 g (yield 84%) of a pure phenacylpyridinium bromide derivative (compound No. 7).
6). The compound was identified by using nuclear magnetic resonance spectrum, infrared absorption spectrum and elemental analysis. Obtained N-
(Methoxyphenacyl) pyridinium Br salt derivative No.
When the SHG intensity of 76 was measured by the above method, generation of SHG of 43.7 with respect to urea could be confirmed.

Examples 77-100 Examples 77-100 were carried out according to Example 76. The measured SHG values are shown in Table 4. (Compound No.
77-100).

Example 101 was carried out in accordance with Example 76. The compound is shown below.

[Chemical 10] The secondary high frequency generation intensity ratio of Chemical Formula 10 was 7.01.

Example 102 N-ethylpyridinium PF6 salt derivative (Compound No. 2,
A bulk single crystal was grown from the acetone solution of Chemical formula 7) using a solution growth method. Cultivated for about 3 weeks, about 20 × 20 ×
A 30 mm square single crystal was obtained. This single crystal has a fundamental wave 1064
of Nd; YAG laser of nm, Type 1, 2
It was confirmed that angular phase matching was achieved in both cases. As a comparison sample, KTP (effective nonlinear optical constant d in Type 2)
eff 17.0 pm / V) was used to measure the effective nonlinear optical constant deff of compound No. 2,
In the case of pel, deff is 37.6 pm / V, and
In the case of e2, deff was 19.8 pm / V.

The compound No. 2 has a Vickers hardness of 53 Vickers, which is comparable to 56 Vickers of LAP (L-arginine phosphate monohydrate), and is attractive for workability such as cutting and polishing. I was able to confirm that.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

[Table 3]

[0034]

[Table 4]

[0035]

[Table 5]

[0036]

[Table 6]

[0037]

[Table 7]

[0038]

[Table 8]

[0039]

[Table 9]

[0040]

[Table 10]

[0041]

INDUSTRIAL APPLICABILITY As described above, the organic compound of the present invention is a material which easily has a crystal structure having no central symmetry and has a high conversion efficiency. Since the compound of the present invention is an organic ionic compound, V
Organic nonlinear optical material with high ickers hardness, high melting point, low sublimability, low water absorption, excellent storage stability, extremely high nonlinear susceptibility, and excellent laser edge property. Can be provided. Therefore, it is effective for optical information and optical communication including wavelength conversion elements for semiconductor lasers.

Claims (1)

[Claims] 1. A non-linear optical material comprising a 1,3-diketone derivative represented by the following general formula 1. [Chemical 1] (In the formula, R ^a may be different or the same, and an amino group, a substituted amino group substituted with a group having 1 to 12 carbon atoms, a cyclic amino group, an alkyl group, a halogen-substituted alkyl group, an alkoxy group, a mercaptoalkoxy group, It is a group selected from a halogen, a carboxyl group, an alkoxycarbonyl group, an alkanoyloxy group having 1 to 12 carbon atoms, a nitro group, a cyano group, an alkanoylamide group, a trifluoromethyl group and a sulfonyl group, and S is the number thereof. 1 to 5. Substituent P is a pyridinium base represented by the following Chemical Formula 2, and an organic substituent may be substituted at a position other than N.) (In Formula 2, R ^b is an alkyl group having 1 to 15 carbon atoms,
A halogen-substituted alkyl group, a substituted amino group, or an alkyl group having a hydroxyl group, an aromatic methyl group, an aromatic carbonyl group, or an aromatic carbonyl group. The counter anion X is halogen (fluorine, bromine, chlorine,
(Iodine), PF ₆ , Sb F ₆ , As F ₆ , BF ₄ , Cl
O ₄ , IO ₃ , CH ₃ COO, CF ₃ COO, C ₂ F ₅
COO, a benzoic acid residue or a benzenesulfonic acid residue (the aromatic nucleus may have a substituent). )