JP2000264874A - Disulfide derivative and self-organization membrane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new disulfide derivative that can form a self-organization membrane comprising a specific disulfide derivative and has a structure reacting to light. SOLUTION: This compound is represented by the formula (R1 is a 1-8C alkyl, cyano or the like; n is an integer of 6<=n<=18; R2 is a 1-24 alkyl), typically 12-[4-(4-hexylphenylazo)phenoxy]dodecyl octadecyl disulfide. The compound of the formula is prepared by allowing a hydroxyazobenzene derivative to react with a dibromoalkane, dissolving the resultant produce, a bromoalkyloxyazobenzene derivative in DMF and adding an aqueous solution of sodium thiosulfate under stirring for several hours, pouring the resulting solution into water, washing the precipitating Bunte salt of azobenzene derivative for removing nonreacted substances, then dissolving an alkanethiol in a mixture of tetrahydrofuran and methanol and allowing them to react with an aqueous solution of sodium hydroxide under an atmosphere of Ar, further adding a solution of the Bunte salt in a mixture of DMF and methanol to the reaction mixture under stirring and isolating the product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a disulfide compound and a self-assembled film comprising the same.

[0002]

2. Description of the Related Art It is known that a disulfide or thiol derivative having an alkyl group is selectively adsorbed on a gold or other noble metal surface via a gold (other noble metal) -sulfur bond, thereby creating a dense structure on the surface. Have been
(RG Nuzzo, BR Zegarski, LH Dubois, J. Am.
Chem. Soc., 109, 733-740 (1987)). Further, it is known that a thin film prepared using a long-chain alkyl disulfide or thiol derivative is selectively adsorbed on a crystal structure surface using gold as a substrate, and shows an aggregated state (L. Strong,
GM Whitesides, Langmuir, 4, 546-558 (1988)).
Each of these films is called a self-assembled film. These are made using thiols and disulfides,
In both cases, it has been confirmed that the molecules constituting the film have a densely packed structure. Of these, thiols are liable to undergo air oxidation during the reaction to form disulfides. Therefore, if the disulfides are synthesized in advance as raw materials, the target substance can be obtained as a more stable compound.

[0003] These self-assembled films have a thickness equivalent to one molecule, and are known to be ultrathin. Therefore, the derivatives obtained by using these disulfide or thiol compounds can achieve the object as a noble metal surface modifier by using only a trace amount. By making use of such characteristics, the detection surface of the biosensor (JP-A-1-51140)
5) Inventions such as application to biosensors (JP-A-7-24631) and electrochemical sensors (JP-A-8-233773) by combination with surface plasmon measurement are known. Also, a metal surface treatment agent for bonding metal surfaces to each other (Japanese Patent Laid-Open No. 9-7175)
The invention of 3) is known. Meanwhile, a conventionally known self-assembled film has a very dense structure. Therefore, even if an attempt is made to change the molecular structure in order to exert a function on the film, the molecular structure cannot be changed because there is no free space required for the change in the film structure. For example, when the long-chain alkane thiols having an azobenzene group is adsorbed onto gold crystals, molecules occupied area per azobenzene units is only 0.24 nm ^2, which is intended to do away only about 5Å intermolecularly , A very dense structure has already been observed (a: H. Wolf, H. Ringsdrof, E. Delamarche, T. Ta
kami, B. Michael, Ch. Gerber, M. Jaschke, H.-J. Bu
tt, E. Bamberge, J phys. Chem., 99, 7102-7105 (199
5) R. Wang, T. Iyoda, L. Jiang, DA Tryk, K. Hashi
moto, A. Fujishima, J. Electroana. Chem., 438, 213
-219 (1997)). In general, it is known that an azobenzene group is photoisomerized from a trans form to a cis form by absorbing ultraviolet light, and these substances are known as photochromic compounds. However, as described above, the structure of the self-assembled film is formed very densely and there is no free space. Therefore, it has been found that the isomerization ratio is only 5% or less even when irradiated with ultraviolet rays. (R.
Wang, T. Iyoda, L. Jiang, DA Tryk, K. Hashimot
o, A. Fujishima, J. Electroanal.Chem., 438,213-219
(1997)). This is considered to be due to the absence of free space for isomerization. For this reason, with respect to the self-assembled monolayer, the emergence of a self-assembled monolayer having a sufficient space for changing the molecular structure required for expressing its function is desired.

[0004]

An object of the present invention is to provide a novel disulfide compound and a self-assembled film obtained by using the compound, since the molecular structure required for expressing its function can be changed. The purpose of the present invention is to provide a self-assembled film in which sufficient space exists.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies on the above-mentioned problems, and as a result, have found the following and completed the present invention. Asymmetric disulfides with azobenzene groups were synthesized. At this time, as the asymmetric disulfide derivative, one obtained by introducing an azobenzene group from a disulfide site via an alkyl spacer in advance and modifying the other with a different substituent that does not exceed this length is used. When an asymmetric disulfide having an azobenzene group is formed into a film, the azobenzene group appears on the outermost surface of the self-assembled film. In addition, the amount of azobenzene introduced to the surface is reduced to half and becomes uniform at the molecular level, as compared with a normal self-assembled film of azobenzene-containing thiols. Therefore, a space that causes photoisomerization can be generated from this.

That is, according to the present invention, the following inventions are provided. General formula

Embedded image (1) (wherein, R1 represents an alkyl group having 8 to 1 carbon atoms and having a linear or branched chain, a cyano group, a nitro group, a hydrogen atom or a halogen atom. N is in the range of 18 ≧ n ≧ 6) R2 represents an integer of 24 to 1 having a carbon number not exceeding n + 6.
Represents an alkyl group having a straight or branched chain. ), And a monomolecular film comprising an aggregate of the above-mentioned disulfide derivative compound.

[Detailed description of the invention] The disulfide derivative of the present invention
General formula

Embedded image (1) (wherein, R1 represents a straight-chain or branched-chain alkyl group, a cyano group, a nitro group, a hydrogen atom or a halogen atom having 8 to 1 carbon atoms. N represents 18 ≧ n ≧ 6 R2 represents a linear or branched alkyl group having a carbon number not exceeding n + 6 and in the range of 24 to 1.)
Is a disulfide derivative compound represented by The disulfide derivative having the above structure has a feature in its structure, and this feature is characterized in that, on one side, an azobenzene group is introduced from a disulfide site via an O (CH ₂ ) n group which is a spacer group,
Still another is a different substituent R which does not exceed this length.
_The point is that it is modified with ₂ . When a self-assembled film is formed by the asymmetric disulfide derivative, the sulfur site is selectively adsorbed on the gold surface, and thus the surface layer of the prepared self-assembled film is located at the end of the asymmetric disulfide molecule. An azobenzene group will appear.
Therefore, the outermost surface of the film is present R ₁ is para substituent azobenzene group, a combination of an azobenzene group and R _1, so that the surface properties of the film are determined. R
_{When 1} represents an alkyl group, it is an alkyl group having 8 to ₁ carbon atoms and having a straight or branched chain. When the number of carbon atoms exceeds 8, it is difficult to obtain a reagent necessary for the synthesis and it is hardly soluble in a reaction solvent for forming an azobenzene skeleton, which is not preferable. Further, there is no alkyl group having less than 1 carbon atom. When R ₁ represents a halogen atom, it represents any of chlorine, fluorine, bromine and iodine.
R ₁ is, in addition to these groups and atoms, a cyano group,
Or a nitro group. When a nitro group is introduced into R ₁ , the large permanent dipole moment has the effect of increasing the surface energy of the self-assembled film, and when an alkyl group or a halogen atom is used as a substituent, This has the effect of lowering the surface energy of the self-assembled film.

By introducing various substituents into azobenzene, the surface properties of a film to be formed later can be controlled. Since the substituents R ₁ para azobenzene in the self-assembled film in particular is exposed on the outermost surface, especially a cyano group having a large electrostatic interactions, a nitro group leads to hydrophilic surface, Alkyl groups, hydrogen atoms, halogen atoms, etc. create a hydrophobic surface. In addition, the cis-trans photoisomerization of azobenzene can significantly change the dispersing power and electrostatic interaction due to the cis-trans photoisomerization, and reversibly control the surface energy using the photoreaction of azobenzene. I can do it.

When a self-assembled film composed of an aggregate of the above-mentioned asymmetric disulfide derivatives is formed on a metal surface, a long-chain alkylene group existing from an adsorption site sulfur to an azobenzene site works effectively. that is,
This is because the interaction between the alkylene groups of the adsorbed asymmetric disulfides increases the cohesive force of the adsorbed asymmetric disulfides in the film in the lateral direction, whereby an ordered structure can be created. For this purpose, the alkylene chain length n of the spacer group represented by O (CH ₂ ) n is 6 or more and 18 or less (18 ≧ n ≧
6) is desirable

The alkyl chain (R ₂ ) on the opposite side of the disulfide site is a linear or branched alkyl group. This alkyl group does not exceed the length from N = N, which is the bending site at the time of bending, to the sulfur atom, where the azobenzene group is affected by the photoreaction.
That is, the alkyl group (R ₂ ) needs to have a carbon number of (n + 6) or less. If the length of R ₂ is (n + 7) or more, the space required for the photoreaction at the azobenzene site will be filled with the alkyl group, so that an actual effect cannot be obtained.

From the above description, the specific structural formula of the disulfide derivative compound of the present invention is as follows.

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

The method for producing the disulfide derivative compound of the present invention is as follows. A method for producing a bromoalkyloxyazobenzene derivative as a raw material is a compound obtained by reacting a hydroxyazobenzene derivative with a dibromoalkane. Such a production method is described in the following documents,
Where these are mentioned (MD Everaars, A.
TM Marcelis, EJR Sudholter, Liebigs, An.,
1, 21 (1997)). First,
The obtained product is dissolved in DMF at 60 ° C., an aqueous solution of sodium thiosulfate is slowly added, and the mixture is stirred for several hours. Drain this solution in water and remove the azobenzene derivative
Wash the Bunte salt thoroughly with acetone to remove unreacted material. Next, the alkanethiol is converted to tetrahydrofuran (TH
Dissolve in a mixed solvent of F) and methanol, and react with an aqueous solution of sodium hydroxide for 1 hour under Ar. To this solution, the above-mentioned mixed solution of Bunte salt in DMF and methanol is added and stirred for 6 hours. This Bunte salt is poorly soluble because it has both an inorganic salt site and a nonpolar linear site. Moreover,
Since this reaction is a reaction containing water, ethanol is usually used as a solvent.Here, by using a mixed solvent of THF and methanol or a mixed solvent of DMF and methanol, phase separation from an aqueous layer does not occur and organic substances are removed. However, it can act as a good solvent to perform the reaction. The desired asymmetric disulfide compound is isolated by recrystallization and column chromatography. The structure of the obtained product can be confirmed by various methods. In the present invention, NMR was used.

The formation of a film using the disulfide derivative compound of the present invention is performed as follows. As the gold substrate, gold is vacuum-deposited on mica or a glass substrate using a vacuum deposition apparatus, or a commercially available gold substrate is used. Next, the synthesized disulfide is dissolved in a solvent, and the gold substrate is immersed in this solution. The lifted substrate is rinsed with a pure organic solvent for washing, and excess disulfide is washed away to form a self-assembled film.

[0014]

EXAMPLES Example 1 12- [4- (4-hexylphenylazo) phenoxy] dodecyl octadecyl
Preparation of disulfide 4- (12-bromododecyloxy) -4'-hexylazobenzene 1.03g
Dissolve in 40 ml of DMF at 60 ° C, and add 0.56 g of Na2S2O35H2O in 5 ml of water
The solution was added slowly. Keep this solution at 60 ° C for 4 hours
Stirred. Water was poured into the reaction solution, and the precipitate was filtered. Sa
Further, the residue is suspended in acetone and filtered, and the unreacted raw material is removed.
Was removed. Next, 0.572 g of octadecanethiol was added to TH
Dissolve in a mixed solvent of F and methanol (14ml: 6ml) and Ar atmosphere
Add 1 ml of NaOH (0.80 g) aqueous solution and stir for 1 hour
Was. Add the filtrate (Azobenzene bunte)
Salt) with dimethylacetamide and methanol (28ml: 12ml)
What was melt | dissolved in the mixed solution of above was dripped. Precipitation during dropping
Things were seen. The solution was stirred under Ar atmosphere for 6 hours
Thereafter, water was added and the precipitate was separated by filtration. Mix the cake with THF,
The undissolved residue was removed by filtration. Concentrate the filtrate and add ethanol
Recrystallized with a mixed solvent of
Crystallized. The crude product obtained is purified with hexane and chloroform.
Using the mixed solvent of (3: 1) as the developing solvent, column chromatography
G separation was performed. 490 mg of yellow-white amorphous solid
Was. Melting point measurement shows that the compound is liquid crystalline
Was. Yield: 32% mp: 77.0-78.0 ° C TNI: 79.5 ° C 1H-NMR (CDCl3); d = 0.89 (3H, t, -CH3), 0.90 (3H,
t, -CH3), 1.4-1.6 (52H, m, CH2-CH2-CH2), 1.66 (4H,
t, t, S-S-CH2-CH2), 1.68 (2H, t, t, Ar-CH2-CH2),
1.82 (2H, t, t, Ar-O-CH2-CH2), 2.69 (2H, t, Ar-CH
2), 2.69 (4H, t, S-S-CH2), 4.04 (2H, t, Ar-O-CH2),
 7.01 (2H, d, Ar-H), 7.30 (2H, d, Ar-H), 7.80 (2
H, d, Ar-H), 7.90 (2H, d, Ar-HCalcd. For C 18H28Br2O2: C, 49.56; H, 6.47. Foun
d: C, 49.94; H, 6.39. E.A .: C: H: N: S cal. 75.13: 10.77: 3.65: 8.36 found 7
5.34: 10.87: 3.57: 8.38

Example 2 12- [4- (4-hexylphenylazo) phenoxy] dodecyl dodecyl di
Preparation of sulfide 4- (12-bromododecyloxy) -4'-hexylazobenzene 0.94 g 6
Dissolve in 40 ml of 0 ° C DMF, and add 0.56 g of Na2S2O3.5H2O in 5 ml of water
The solution was added slowly. Keep this solution at 60 ° C for 4 hours
While stirring. Pour water into the reaction solution and filter the precipitate
Was. Further, the residue is suspended in acetone, filtered and unreacted.
The raw material was removed. Next, in 1 ml of NaOH (0.080 g) aqueous solution
Under an Ar atmosphere, 0.40 g of dodecanethiol methanol (2 m
l) The solution was added and stirred for 1 hour. To this solution, filter
(40ml) solution of the product (bunte salt of azobenzene) slowly
It dripped dripping. A precipitate was observed during the dropwise addition. This solution
Was stirred under an Ar atmosphere for 6 hours, and then water was added to remove the precipitate.
It was filtered off. The residue is mixed with THF, and the undissolved residue is filtered and collected.
Removed. The filtrate was concentrated and hexane and ethyl acetate (20
Column chromatography separation using the mixed solvent of 1) as a developing solvent
Was done. Then reconstitute with acetone and hexane respectively
Crystallization was performed and 320 mg of a pale yellow solid was isolated. Yield: 26% mp: 68.5-69.5 ° C 1H-NMR (CDCl3); d = 0.88 (3H, t, -CH3), 0.89 (3H,
t, -CH3), 1.4-1.6 (40H, m, CH2-CH2-CH2), 1.65 (4H,
t, t, S-S-CH2-CH2), 1.67 (2H, t, t, Ar-CH2-CH2),
1.82 (2H, t, t, Ar-O-CH2-CH2), 2.68 (2H, t, Ar-CH
2), 2.68 (4H, t, S-S-CH2), 4.03 (2H, t, Ar-O-CH2),
 6.99 (2H, d, Ar-H), 7.29 (2H, d, Ar-H), 7.79 (2
H, d, Ar-H), 7.89 (2H, d, Ar-HE.A .: C: H: N: S cal. 73.84: 10.33: 4.10: 9.39 found 7
3.80: 10.44: 4.12: 9.37

Example 3 12- [4- (phenylazo) phenoxy] dodecyl dodecyl disulfide
Production method 4- (12-bromododecyloxy) -azobenzene
The synthesis was performed by the same means as in the method. Purification as well
Performed to obtain yellow crystals. Yield: 34% mp: 77.0-78.5 ° C 1H-NMR (CDCl3); d = 0.88 (3H, t, -CH3), 1.2-1.6 (34
H, m, CH2-CH2-CH2), 1.67 (4H, t, t, S-S-CH2-CH2),
1.82 (2H, t, t, Ar-O-CH2-CH2), 2.68 (4H, t, S-S-CH
2), 4.04 (2H, t, Ar-O-CH2), 7.01 (2H, d, Ar-H),
7.43 (1H, t, Ar-H), 7.50 (2H, t, Ar-H), 7.87 (2H,
d, Ar-H), 7.91 (2H, d, Ar-H).

Example 4 12- [4- (4-cyanophenylazo) phenoxy] dodecyl dodecyl di
Preparation of sulfide 4- (12-bromododecyloxy) -4'-cyanoazobenzene 1.00 g
Was synthesized by the same procedure as described above. Purification
Solvent mixture of hexane and ethyl acetate (10: 1)
To perform column chromatography separation, 230 mg of an orange solid
Was isolated. Yield: 18% mp: 75-76 ° C TNI: 81 ° C 1H-NMR (CDCl3); d = 0.88 (3H, t, -CH3), 1.2-1.6 (34
H, m, CH2-CH2-CH2), 1.67 (4H, t, t, S-S-CH2-CH2),
1.83 (2H, t, t, Ar-O-CH2-CH2), 2.68 (4H, t, S-S-CH
2), 4.01 (2H, t, Ar-O-CH2), 7.02 (2H, d, Ar-H),
7.79 (2H, d, Ar-H), 7.94 (4H, d, Ar-H).

Example 5 Gold was vacuum-deposited on a mica substrate at 2.0 × 10 ⁻⁷ torr at a substrate temperature of 350 ° C. at a rate of 1 ° / sec to a film thickness of 1000 °. This was annealed at 550 ° C. for 2 hours to produce a mica substrate having a (111) plane of gold as the outermost surface. The gold substrate was immersed in a 1 mmol / L solution of the above-mentioned disulfide in dichloromethane and stored at room temperature in a dark place for 12 hours. Thereafter, the lifted substrate was rinsed twice with a pure dichloromethane solution, and excess disulfide was washed away to form a self-assembled film. The effect of the film was confirmed as follows. Light irradiation was performed using an ultrahigh pressure mercury lamp as a light source and a colored glass filter attached thereto. As a result, monochromatic light of ultraviolet light (365 nm) was extracted, and a light having a light amount of ² J / cm ² was irradiated on the film surface. Next, the combination of colored glass filters was changed, monochromatic light of visible light (436 nm) was extracted, and the same amount of light of ² J / cm ² was applied to the film surface. The contact angles of the irradiated films were measured. The result is as shown in FIG. FIG. 1 shows that the contact angle was changed by irradiation with ultraviolet light, and the value returned to the original value by irradiation with visible light. That is, this means that azobenzene isomerized into cis-form by ultraviolet irradiation and returned to trans-form by visible ray irradiation. This indicates that the structure of the film was changed by the light irradiation. Therefore, it was demonstrated that a photoreaction in a self-assembled film, which was impossible so far, occurred.

[0019]

According to the present invention, a novel disulfide derivative compound can be obtained, and a self-assembled film having a structure capable of responding to light can be obtained using the compound. When a cyano group or a nitro group is introduced as a substituent of azobenzene, the large permanent dipole moment has the effect of increasing the surface energy of the self-assembled film. When the substituent is used, there is an effect of lowering the surface energy of the self-assembled film. In any case, these are preferable. By combining this with the photoreaction of the azobenzene moiety, the surface properties can be reversibly controlled over a wide range. That is, it is possible to obtain an ultrathin film capable of controlling surface properties such as surface wettability, adhesiveness, and friction with light.

[Brief description of the drawings]

FIG. 1 shows a change in a contact angle when a film made of a disulfide compound derivative is irradiated with ultraviolet rays and visible rays.

[Explanation of symbols]

 Chemical formulas 2 to 5 each represent the compound described in 0011.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junichi Nagasawa 1-1-1, Higashi, Tsukuba, Ibaraki Pref. Institute of Industrial Science and Technology (72) Inventor Fusae Nakanishi 1-1-1, Higashi, Tsukuba, Ibaraki Pref. Within the Institute of Engineering Technology (72) Inventor Takashi Tamaki 1-1-1 Higashi, Tsukuba City, Ibaraki Prefecture F-term in the Institute of Materials Science and Technology, FIT (reference) 4H006 AA01 AA03 AB99

Claims (2)

[Claims] 1. A compound of the general formula (1) (In the formula, R1 represents a straight or branched alkyl group, a cyano group, a nitro group, a hydrogen atom or a halogen atom having 8 to 1 carbon atoms. N is in the range of 18 ≧ n ≧ 6. R2 represents an integer of 24 to 1 having a carbon number not exceeding n + 6.
Represents an alkyl group having a straight or branched chain. A disulfide derivative compound represented by the formula: 2. A self-assembled film comprising an aggregate of the disulfide derivative compound according to claim 1.