JP2800920B2 - Method for producing metal coordinating organosilicon polymer thin film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a porous metal-coordinating organosilicon polymer thin film having a thin film structure controlled at a molecular level.

[Conventional technology]

A material in which a metal coordinating functional group is introduced on the surface of an inorganic polymer such as silica gel is used as a material separation membrane, a catalyst, or the like.

As a method for introducing a metal coordinating functional group, a method based on a covalent bond with a polymer surface has been widely adopted. For example, by applying a trialkoxysilane having various metal coordinating functional groups to silica gel to modify the surface of the silica gel so as to have a function of separating various metal ions, “Surface” Vol. 27, No. 360 Page (written by Kikuo Terada). In addition, the use of silica gel surface-treated with (MeO) ₃ Si (CH ₂ ) ₃ PPh ₂ carrying rhodium-osmium mixed clusters as a catalyst for the hydrogenation of ethylene and the isomerization of butene is called “surface Vol. 26, No. 435
Page (by Jun Fukuoka and Masaru Ichikawa).

However, when a metal coordinating functional group is introduced by these methods, there is a problem that the amount introduced per unit weight of silica gel is low. To increase this amount,
It is necessary to finely pulverize the simple substance to be treated to increase the surface area. However, fine powder having a large surface area has a high surface activity, which makes handling and storage complicated and troublesome.

In order to solve this problem, a method of preparing a metal-coordinating organosilicon polymer from an alkoxysilane compound having a metal-coordinating functional group by a sol-gel method has been introduced in, for example, JP-A-49-52194. ing. In this method, an organosilicon polymer gel containing a phosphorus atom is produced by treating a trialkoxysilane having a hydrocarbon group substituted with a phosphorus atom in hot water, followed by drying and heat treatment. It is also disclosed that a catalyst is produced by coordinating a transition metal with the polymer gel.

[Problems to be solved by the invention]

However, according to the sol-gel method, since the structure of the obtained polymer gel is three-dimensionally and continuously expanded, diffusion of metal atoms to various metal coordinating functional groups is suppressed. In addition, when the obtained metal-coordinating organosilicon polymer is used as a catalyst, diffusion of a reaction substrate is suppressed due to a structure that is continuously spread three-dimensionally.

To eliminate these defects, it is conceivable to reduce the thickness of the organic silicon polymer. However, in the case of the conventional sol-gel method, it is difficult to reduce the thickness of the organic silicon polymer thin film to a submicron order. Moreover, since the obtained thin film is a continuum having a three-dimensional internal structure,
The substance diffusion inside is substantially the same as in the case of ordinary silica gel.

Therefore, the present invention utilizes the aggregation state of the amphipathic substance present in the solvent, and forms a film from the solution containing the amphipathic substance and the alkoxysilane compound as the organosilicon polymer precursor by a development method. The purpose of the present invention is to produce a metal coordinating functional group-containing organosilicon polymer thin film having a thin film multilayer structure controlled at a molecular level or an organosilicon polymer thin film in which a metal is coordinated to the metal coordinating functional group. And

[Means for solving the problem]

In order to achieve the object, the method for producing a metal-coordinating organosilicon polymer thin film of the present invention comprises an amphiphilic compound having polar and hydrophobic groups added to both ends of a molecule and a metal-coordinating alkoxysilane represented by the following formula: A developing solution containing a compound is prepared, and after developing the developing solution on the surface of the substrate, the solvent is removed from the liquid film on the substrate.

_{(X m R) n Si (} OR ') 4-n In order to promote the hydrolysis and polycondensation reaction of the remaining SiOR ', SiOH, etc. on the metal coordinating organosilicon polymer thin film produced in this way, a chemical substance using a basic substance or an acidic substance was used. And / or heat treatment.

As a chemical treatment, for example, HCl, HBr, HNO ₃ , H ₂ SO ₄ , CH ₃
A method of exposing the thin film to a gas, liquid, or solution of COOH, NH ₃ , amine, NaOH, or the like is cited. Further, a method of inactivating residual SiOH or SiOR ′ by treatment with a gas, a liquid or a solution of a silazane such as monoalkoxysilane, monochlorosilane or hexamethylsilazane may be employed.

On the other hand, as a thermal treatment, there is a method of heating a thin film in air, in an inert gas such as nitrogen, argon, or helium or in a vacuum.

The amphiphilic compound is extracted from the metal-coordinating organosilicon polymer thin film after performing such chemical treatment or thermal treatment, or directly without performing such treatment.

When coordinating a metal to the obtained metal-coordinating organic silicon polymer thin film, the metal-coordinating organic silicon polymer thin film is immersed in a solution of a metal-containing compound. Alternatively, when a metal-coordinating organosilicon polymer thin film is produced, a predetermined metal can be coordinated by coexisting a metal-containing compound in a developing solution.

The metal to be coordinated with the organic silicon polymer thin film is not particularly limited, but specifically, a transition metal such as chromium, iron, nickel, cobalt, copper, rhodium, palladium, platinum, lanthanum, Rare earth metals such as cerium and europium are listed. When these metal compounds are used as a solution, they are used in the form of soluble salts or soluble complexes of low molecular weight ligands, and when used as vapor, they are sublimable compounds such as simple metals or carbonyl complexes. Used in the form of

[Action]

According to the production method of the present invention, a regular molecular organization formed by an amphiphilic compound is used as a reaction field, and a metal-coordinating polymer is obtained by hydrolysis and polycondensation of an alkoxysilane compound having a metal-coordinating functional group. A siloxane gel grows. When this amphiphilic compound is dissolved or dispersed in a medium such as an aqueous solution, it forms a molecular aggregate such as a sphere, a disk, a rod, and a lamella. The mode or mode of aggregation of this molecular assembly is determined by the affinity of the polar group or hydrophobic group constituting the amphiphilic compound with the medium, and the molecular orientation resulting from the molecular structure of the hydrophobic group. When a metal coordinating alkoxysilane compound is added thereto, the metal coordinating alkoxysilane compound is hydrolyzed, dispersed in a medium, and fixed by crosslinking using a molecular assembly as a template.

Therefore, the pore structure of the metal coordinating organosilicon thin film produced by the method of the present invention reflects the morphology of the molecular assembly formed by the amphiphilic compound, and has a molecular level precision. Therefore, by appropriately selecting the amphiphilic compound, it becomes possible to control the morphology and size of the pores.

Due to such a unique structure, the obtained thin film dramatically increases the surface area per unit weight, the amount of functional group introduced, and the amount of coordinating metal introduced, as compared with the surface-modified silica gel. . Moreover, since the space around the functional group and the metal coordinated to the functional group is pseudo-two-dimensional, selectivity based on the three-dimensional structure of the chemical species that can approach the functional group and the metal can be expected.

Specific examples of the metal coordinating functional group X include the following. Where R ¹ , R ² and R ³ are hydrogen atoms,
It represents alkyl or aryl, and R ₄ and R ₅ represent OH, alkyl, aryl, alkoxyl and aryloxyl.

-OR ¹ (alcohol, phenol, ether), -COOH (carboxylic acid), -COR ¹ (ketone), -NR ¹ R ² (amine), -N = CR ¹ R ² (imine), -CN (nitrile) , -NC (isonitrile), -NR ¹ CONR ² R ³ (urea derivative) -SR ¹ (mercaptan, sulfide) -PR ⁴ R ⁵ (phosphine, phosphinite, phosphonite) -OPR ⁴ R ⁵ (phosphinite, phosphonite, phosphite ^{) -P (O) R 4 R} 5 ( phosphine oxide, containing phosphonate, ^{phosphate) -OR (O) R 4 R} 5 ( Osufinaito, phosphonate, phosphate), oxygen, nitrogen, sulfur, one or more either phosphorus The following are relatively easily available as alkoxysilane compounds having these metal coordinating functional groups.

- Nitrogen-containing type _{- (MeO) 3 Si- (CH} 2) 3 -NH 2, (EtO) 3 Si- (CH 2) 3 -
_{NH 2, (MeO) 3 Si-} (CH 2) 3 -NHMe, (MeO) 3 Si- (CH 2) 3 -NH-CH 2 CH = CH (MeO) ₃ Si— (CH ₂ ) ₃ —NHφ (MeO) ₃ Si— (CH ₂ ) ₃ —NMe ₂ (MeO) ₃ Si— (CH ₂ ) ₃ —NEt ₂ (MeO) ₃ Si— (CH ₂ ) ₄ —NH ₂ (MeO) ₃ Si— (CH ₂ ) ₁₁ —NH _{2 [(EtO) 3 Si- (CH} 2) 3 -] 2 -NH (MeO) 3 Si-CH 2 -NH-CH 2 CH 2 -NN 2 (MeO) 3 Si- (CH 2) 3 -NH-CH _{2 CH 2 -NH 2 (MeO)} 3 Si- (CH 2) 3 -NH- (CH 2) 6 -NH 2 _{(MeO) 3 Si- (CH 2} ) 3 -NH-CH 2 CH 2 -NH- (CH 2) 3 -
_{Si (OMe) 3 (MeO)} 3 Si- (CH 2) 3 -NH-CH 2 CH 2 -NH-CH 2 CH 2 -NH 2 (MeO) 3 Si- (CH 2) 2 -CN (EtO) 3 _{Si- (CH 2) 2 -CN (} MeO) 3 Si- (CH 2) 3 -CN (EtO) 3 Si- (CH 2) 3 -CN (EtO) ₃ Si— (CH ₂ ) ₃ —NHC (O) NH ₂ (EtO) ₃ Si— (CH ₂ ) ₃ —NHC (O) NHCHMeφ—Nitrogen and oxygen containing type— (EtO) ₃ Si— (CH _{2) 3 -N (CH 2 CH} 2 OH) 2 (EtO) 3 Si-CH = CHCMe 2 -O- (CH 2) 3 -NH 2 - nitrogen and sulfur-containing type _{- (EtO) 3 Si- (CH} 2 ) ₂ —S—CH ₂ CH ₂ NH ₂ —oxygen containing— (EtO) ₃ Si— (CH ₂ ) ₃ —CH (COOEt) ₂ - phosphorus containing type _{- (EtO) 3 Si- (CH} 2) 2 -Pφ 2 - Sulfur will contain type _{- (MeO) 3 Si-CH} 2 -SH (MeO) 3 Si- (CH 2) 3 -SH (EtO) _{3 Si- (CH 2) 3 -SH} (MeO) 3 Si- (CH 2) 3 -S-CH 2 CH = CH 2 In addition to these alkoxysilane compounds having a coordinating functional group, the coordinating environment around the coordinating functional group by the hydrocarbon group, the environment around the metal atom coordinated to the ranged functional group,
It is also possible to add an alkoxysilane compound or a chlorosilane compound that does not contain a coordinating functional group for the purpose of controlling the crosslink density, the residual amount of SiOH, SiOR ′ and the like.

Also, the amphiphilic compound has a polar group at one end of the same molecule,
A compound having a relatively long molecular structure having a hydrophobic group at the other end, and may have a linear or branched chain.

Examples of the polar group include sulfonates, sulfates, ammonium salts, polyamine salts, carboxylate salts, phosphate salts, phosphonate salts, phosphonium salts, polyethers, alcohols, polyols containing sugar residues, and the like. Combinations of the groups can be used. On the other hand, examples of the hydrophobic group include an alkyl group, an alkylaryl group, an alicyclic group, a condensed polycyclic group and the like, and a combination thereof.
Further, some or all of the hydrogen atoms of these groups may be substituted with fluorine atoms.

The following are specifically listed as amphiphilic compounds.

CH ₃ (CH ₂ ) ₁₀₀ (CH ₂ CH ₂ O) ₉ H The developing solution is prepared by dissolving or dispersing a predetermined amount of an amphiphilic compound and an alkoxysilane compound in a solvent. As the solvent, water is used in many cases, but an organic solvent containing water in an amount necessary for hydrolysis of the alkoxysilane compound can also be used.

In order to form a thin film having a structure controlled at a molecular level according to the present invention, these alkoxysilane compounds undergo hydrolysis / polycondensation reaction at least partially during preparation of a developing solution or removal of a solvent on a substrate. It is necessary that a molecular assembly of the amphiphile is formed and maintained between these reactions. Typical methods for preparing a developing solution satisfying these requirements include ultrasonic irradiation,
There is a method of heating the developing solution at a temperature equal to or lower than the boiling point of the solvent. Similarly, it is preferable that the solvent is gradually removed in order to uniformly grow the siloxane bond and maintain the molecular assembly of the amphiphilic compound.

Examples of the substrate on which the developing solution is developed include a plate or a film of glass, quartz, organic polymer, graphite, or the like. The surface of the substrate can be subjected to a hydrophilic treatment or a hydrophobic treatment depending on the type of the developing solution. For example, in order to spread the developing solution on a predetermined area on the substrate surface,
A treatment for making a part of the substrate surface hydrophobic and making the remaining part hydrophilic is also an effective method.

Further, the thin film of the present invention is useful even in a form in which no metal is introduced. Can be used for

The method for producing a thin film according to the present invention is classified into the following specific steps according to contact with a metal-containing solution, chemical or thermal treatment, and the like.

After irradiating the mixture of the amphiphilic substance, the alkoxysilane compound, and the metal compound with ultrasonic waves, the mixture is spread on an appropriate substrate and subjected to a chemical treatment and / or a thermal treatment as necessary. As a result, a thin film in which the metal is coordinated is manufactured.

After developing a thin film from a similar mixture, the amphiphile is extracted. As a result, a metal-coordinated thin film is obtained.

After irradiating the mixture of the amphiphilic substance and the alkoxysilane compound with ultrasonic waves, the mixture is spread on an appropriate substrate and subjected to a chemical treatment and / or a thermal treatment as necessary. Thereby, a coordinating organic silicon thin film containing no metal is obtained.

By treating the thin film obtained in the step with a metal-containing solution, a thin film in which a metal is coordinated can be obtained.

The solvent is extracted and removed from the thin film obtained in the step to produce a metal-free thin film.

By immersing the thin film produced in the above step in a metal-containing solution, a thin film in which a metal is coordinated is obtained.

〔Example〕

 Hereinafter, the present invention will be described specifically with reference to examples.

-Example 1-An amphiphilic compound of the following formula was used.

The compound of the following formula was used as the alkoxysilane.

(CH ₃ CH ₂ O) ₃ Si (CH ₂ ) ₃ NH ₂ ... (2) These amphiphilic compounds, alkoxysilanes and metal compounds are mixed in water at the ratios shown in Table 1 and For 2 to 3 minutes to obtain a uniform and transparent yellow developing solution. Then, a frame of cellulose acetate was placed on the fluoropore, and the developing solution was gently developed therein. And
Water was gradually removed under an atmosphere of 25 ° C. and a relative humidity of 65% for 3 days.

The resulting thin films had the colors shown in Table 1 and were self-holding films each having a thickness of 100 μm or less. In addition, it was confirmed by the wide-angle X-ray diffraction method that there was a regular structure of every 38 ° in a direction perpendicular to the thin film surface.

Example 2 The thin films of Test Nos. 1 and 2 were immersed in chloroform at room temperature for 5 days to extract an amphiphilic compound. Inspection of the IR spectrum after the treatment revealed that the peak at 1248 cm ^-1 based on the stretching vibration of the ether bond of the amphiphilic compound used disappeared, confirming that the amphiphilic compound was almost completely removed. Was.

The resulting thin film had a thickness of 50 μm or less, was almost colorless and transparent, and had a mica-like self-holding film.
Observation of the fracture surface of this thin film with a scanning electron microscope (SEM) revealed that the film had a thickness of 100 mm spread parallel to the thin film surface, reflecting the morphology of lamellar molecular aggregates formed by the amphiphilic compound used. It had a structure in which many thin feeds were stacked.

Further, the obtained thin film was immersed in a melanol solution shown in Table 2 at room temperature for 10 days. The thin film after the treatment is finely pulverized, and X
When the ratio of the number of metal atoms to the number of nitrogen atoms was measured by X-ray photoelectron spectroscopy (XPS), the results shown in Table 2 were obtained.

-Comparative Example-Except for removing the amphiphilic compound from the conditions of Test No. 2,
A colorless and transparent thin film was obtained in the same manner as in Example 1. This thin film was treated with chloroform as in Example 2. Then, when the fracture surface was observed by SEM, this thin film was composed of a three-dimensionally continuous dense single layer.

Then, this thin film was treated with a methanol solution of CuCl ₂ (concentration 1).
Mol /) at room temperature for 10 days, the thin film remained colorless and transparent without discoloration. Furthermore, when the XPS measurement was performed on this thin film in the same manner as in Example 2, no peak due to the 2p orbit of the copper atom was detected.

Example 3 The compound (1) described above and an amphiphilic substance having a structure represented by the following formulas (3) and (4) were used.

Further, as the alkoxysilane compound, the following formula (5)
And a compound having the structure shown in (6).

NH ₂ (CH ₂ CH ₂ NH) ₃ NH (CH ₂ ) ₃ Si (OMe) ₃ ... (5) NC (CH ₂ ) ₃ Si (OEt) ₃ ... (6) These amphiphilic compounds, The developing solution was prepared by adding the alkoxysilane compound and the metal compound so as to have the mixing ratios shown in Table 3, and treating the mixture by the method shown in Table 3 until the system became a uniform and transparent liquid. . Next, the solvent was removed in the same manner as in Example 1. Test No. 7 was left in a vacuum for 8 hours, and the rest was left in a desiccator containing aqueous ammonia for 6 days. by this,
Thin films each having a self-holding property of about 150 μm were obtained.

The color of each thin film and the length of the regular structural unit in the direction perpendicular to the thin film surface measured by the wide-angle X-ray diffraction method,
It is shown in Table 3.

Example 4 The thin films of Test Nos. 7 and 8 were immersed in chloroform at room temperature for 5 days to extract an amphiphilic compound. The IR spectrum showed that the peak at 1248 cm ^-1 due to the stretching vibration of the ether bond of the amphiphilic compound used had disappeared. This confirms that the amphiphilic compound has been almost completely removed.

The obtained thin film had a thickness of 50 μm or less, exhibited almost the same color as before the extraction of the amphiphilic compound, and had self-retention. Observation of the fractured surfaces of these films by SEM revealed that a large number of thin layers with a thickness of about 100 mm spread on the surface of the thin films.

The thin film thus manufactured can be used as a useful functional material in various fields by utilizing the characteristics of the structure whose structure is controlled at the molecular level.
For example, when no metal is contained, it is used as a metal adsorbent, an ion exchanger, a gas adsorbent, or the like. Further, when the metal coordinating functional group is a nitrogen-containing functional group, it is used as a carbon dioxide gas adsorbent, and when the metal coordinating functional group is a hydrogen bonding functional group, it is used as a hydrogen bonding organic substance adsorbent. used. On the other hand, a thin film on which a metal is coordinated is used as a catalyst, a low molecular weight adsorbent, or the like according to the characteristics of the metal.

〔The invention's effect〕

As described above, in the present invention, alkoxysilane is dispersed using a molecular assembly formed by assembling amphiphilic compounds as a template, and hydrolysis and polycondensation are performed in this state. The thin film is a structure having an extremely precise organization at a molecular level. Due to this unique structure, the obtained organosilicon polymer thin film greatly increases the surface area of the thin film, and becomes a thin film material suitable for various uses utilizing a surface reaction.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08J 9/26 102 C08J 9/26 102 // C08L 83:00 (72) Inventor Toyo Kunitake 1 Sakuragaoka, Shimencho, Kasuya-gun, Fukuoka Prefecture 19-3 (58) Field surveyed (Int. Cl. ⁶ , DB name) C08J 5/18 C08J 9/26 C08G 77/14-77/30

Claims (8)

(57) [Claims] 1. A developing solution containing an amphiphilic compound having a polar group and a hydrophobic group added to both ends of a molecule and a metal-coordinating alkoxysilane compound represented by the following formula is prepared. A method for producing a metal-coordinating organosilicon polymer thin film, comprising, after developing, removing a solvent from a liquid film on the substrate. _{(X m R) n Si (} OR ') 4-n 2. A chemical or thermal treatment of the metal coordinating organosilicon polymer thin film produced by the method of claim 1,
A method for producing a metal-coordinating organosilicon polymer thin film, wherein a hydrolysis / polycondensation reaction of residual SiOR ', SiOH and the like is promoted. 3. A method for producing a metal coordinating organosilicon polymer thin film, comprising extracting an amphiphilic substance from the metal coordinating organosilicon polymer thin film produced by the method according to claim 1. 4. A metal coordinating organosilicon polymer, wherein the metal coordinating organosilicon polymer thin film produced by the method according to claim 1 is immersed in a solution containing a metal-containing compound. Manufacturing method of thin film. 5. A thin film of a metal-coordinating organic silicon polymer, wherein a metal-containing compound is present in the developing solution when the metal-coordinating organic silicon polymer thin film is produced by the method according to claim 1. Manufacturing method. 6. A chemical or thermal treatment of a metal coordinating organosilicon polymer thin film produced by the method according to claim 5 to effect hydrolysis and polycondensation of remaining SiOR ', SiOH and the like. A method for producing a metal-coordinating organosilicon polymer thin film, characterized by accelerating the reaction. 7. A method for producing a metal coordinating organosilicon polymer thin film, comprising extracting an amphiphilic substance from the metal coordinating organosilicon polymer thin film produced by the method according to claim 5. 8. A method for producing a metal-coordinating organosilicon polymer thin film, wherein the amphiphilic compound according to claim 1 has a bilayer film-form performance.