JPS5824446B2 - Linear poly(2,5-thienylene) polymer and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel linear poly-(2,5-chenylene) polymer having a 2,5-thennylene group as a repeating unit and a method for producing the same.

Conventionally, several examples of linear polythenylene polymers whose skeleton structure is composed of thiophene rings have been known, as represented by the following formula: However, in all of these polymers, the thiophene ring is incorporated into the skeleton structure of the polymer. The bonding mode when polymerizing is not constant, and the average degree of polymerization n
is a polymer having a small value of 7 or less, and no poly(2,5-chenylene) polymer in which bonding is carried out regularly at the 2 and 5 positions has been obtained at all.

The object of the present invention is to form a linear poly(2/5
- chenylene) polymer.

Another object of the present invention is to provide a method for producing a linear poly(2,5-chenylene) polymer which is regularly bonded at the 2 and 5 positions and has a relatively high average degree of polymerization.

The present invention uses a 2,5-thennylene group represented by the following formula as a repeating unit,
Bonds regularly at the 2nd and 5th positions, with an average degree of polymerization of 14 to 30
A linear poly(2,5-chenylene) polymer is provided.

The linear poly(2,5-thennylene) polymer of the present invention is regularly bonded at the 2 and 5 positions as represented by the following formula:, has a resonance structure represented by the following formula, and has an average degree of polymerization of 14-30
It has a different structure and a higher average degree of polymerization than conventional polythenylene polymers.

The polymer of the present invention has the above resonance structure and is colored in a deep color because it has a pi-electron conjugated system along the main chain.

Further, as the degree of polymerization increases, the pi-electron conjugated system is expanded, and as a result, the position of the thickest absorption in the visible absorption spectrum moves toward the longer wavelength side as the degree of polymerization increases.

As a result, polymers with an average degree of polymerization of about 14 are colored brown, and polymers with an average degree of polymerization of about 20 or more are colored black or reddish-black.

Since the linear poly(2,5-thennylene) polymer of the present invention has the above pi-electron conjugated system, it has inorganic electron acceptors such as iodine, sulfur trioxide, and sulfuric acid, as well as tetracyanoquinodimethane and tetracyanoethylene. It has a high affinity for organic electron acceptors such as, and strongly adsorbs these electron acceptors.

In general, in order for a polymer to exhibit the high affinity for electron acceptors mentioned here, it is essential that a sufficiently expanded pi-electron system exists in the polymer molecule. In the polythenylene polymer, it is necessary that the thiophene rings are regularly bonded at the 2 and 5-1 positions and that the average degree of polymerization thereof is greater than a certain level.

Furthermore, in order for the adduct consisting of a polymer and an electron acceptor to have semiconductor properties, that is, the property that carriers can easily move in the polymer, the average degree of polymerization of the polymer must exceed a certain level. It needs to be big.

The polymers of the present invention meet these requirements.

The polymer of the present invention can be molded by various molding methods for thermoplastic resins such as compression molding, and the molded product has excellent mechanical strength and is an excellent heat-resistant resin with high thermal stability. It is inert to oxygen in the air, and is an electrical insulator when no electron acceptor is added.

Polyacetylene, poly(paraphenylene), poly(phenylene sulfide), etc. are conventionally known as organic semiconductor materials.These polymers are easily affected by oxygen, so electron acceptors have been added to the polymers. Organic semiconductors made of organic semiconductors have drawbacks such as being easily able to absorb oxygen from the air, and exhibiting conductivity only when an extremely toxic electron acceptor such as ASF is added, and therefore lacking in safety for the human body. There are many.

On the other hand, the polymer of the present invention is inert to oxygen in the air and can be converted into a semiconductor by adding an ordinary electron acceptor that is practically non-toxic, making it extremely excellent as a semiconductor material. .

The polymer of the present invention is prepared using a nickel compound as a catalyst in a non-reactive solvent in the substantial absence of water.
- Manufactured by reacting dihalogenated thiophene with magnesium.

This reaction has the following reaction formula: (X in the formula represents a rogen atom).

In such a polymerization reaction by denitrification and rogation using magnesium, it is necessary to use a nickel compound as a catalyst.

When no catalyst is used. However, although the polymerization reaction progresses to some extent, the reaction rate is extremely slow, and the yield of polymer is almost zero even after heating for several days.

The catalyst may be added after the reaction of the 2,5-dihalogenated thiophene and magnesium, or at the beginning of this reaction.

As the nickel compound of the catalyst, NiCl2, NiBr
Nickel halides such as 2, and dichloro(2
・2'-Bipyridine) Nickel NiC12 (bpy)
, dibromobis(triphenylphosphine)nickel N
iBr2(Pph3)2.1-5-cyclooctadienebis(triphenylphosphine)nickelNi(
Preference is given to using nickel complexes such as cod ) (1) p) 13 ) 2.

The amount of catalyst used is 0.5-dihalogenated thiophene. O
A suitable content is 1 to 0.5% by weight.

Non-reactive solvents include ether solvents such as 2.5
- Using a solvent that dissolves the dihalogenated thiophene.

Examples of ether solvents include tetrahydrofuran, diethyl ether, and dibutyl ether.

Furthermore, the reaction is carried out under conditions that minimize the presence of water in the reaction mixture.

The reason for this is that the organomagnesium compound produced as a polymerization reaction active species by the reaction between 2,5-dihalogenated thiophene and magnesium is unstable in water and decomposes, which hinders the progress of the polymerization reaction. This is because it will be done.

Furthermore, the reaction is preferably carried out in an inert atmosphere.

The reason for this is that the organomagnesium compound reacts with moisture, carbon dioxide, and oxygen in the air, and the progress of the polymerization reaction is hindered.

The reaction is usually carried out at room temperature to solvent reflux temperature, although a wide range of temperatures can be used.

The reaction proceeds even at 0°C, but in this case some induction period is required.

The amount of magnesium added is suitably 0.98 to 1.10 gram atoms per mole of 2,5-dino-rogenated thiophene.

Next, the present invention will be explained using experimental examples.

Experimental example 1 2,5-dibromothiophene 5.0f (21 mmol)
was placed in a 200ml four-day flask, and 15ml of dry tetrahydrofuran and 0.51ml of metallic magnesium were added to it.
P (21 milligram atoms) was added and reacted with stirring at room temperature under a dry nitrogen atmosphere.

After about an hour, it was confirmed that the metallic magnesium was almost completely consumed.

Then, 20 mg (0,07 mmol) of dichlorobis(2,2'-bipyridine)nickel N1Cl2 (bpy)
When added and stirred, the polymerization reaction started smoothly at room temperature, and a dark brown polymer began to precipitate.

The polymerization reaction was completed in about 1 hour, but was further heated under refluxing tetrahydrofuran for 2 hours to complete the polymerization reaction.

The formed precipitate was poured into hydrochloric acid and methyl alcohol,
After stirring for 1 hour, the mixture was collected on a glass filter and thoroughly washed with methyl alcohol and water.

Next, this precipitate was extracted with hot methyl alcohol using a Soxhlet extractor for 1 hour to extract and remove low molecular compounds.
By drying, a powdery blackish brown polymer 1.21 was obtained.

This polymer had an average degree of polymerization of about 27.5, as calculated from the average degree of polymerization and weight ratio of the two components separated by hot chloroform extraction as described below.

This polymer showed extremely high thermal stability without melting at 200°C.

The results of thermogravimetric analysis of this polymer conducted under a nitrogen atmosphere are shown in FIG.

From Figure 1, the thermal decomposition of this polymer takes place at 230°C under nitrogen atmosphere.
The residual weight starts at around 900°C, but even at a high temperature of 900°C, it shows a residual weight of about 35% by weight.

As shown in Figure 2, the infrared absorption spectrum of this polymer is 788% based on the 2,5-thennylene group in the main chain of the polymer.
One sharp absorption was observed in CIrL-1, but no other absorption was observed in the out-of-plane bending vibration region.

Also, C-Br appearing near 960cfrL”
Stretching vibration was also small.

This indicates that the produced polymer has a sufficiently large degree of polymerization and is composed of regular repeating units, supporting the structure shown in formula (1).

This dark brown polymer was further extracted with hot chloroform for 50 hours using a Soxhlet extractor.

As a result, 0.26S' (approximately 22% by weight) of powdery brown polymer was extracted with hot chloroform and 0.94P (approximately 78%) of powdery black polymer that was not extracted with hot chloroform.
% by weight) was obtained.

Elemental analysis of the brown hot chloroform soluble polymer was 53.1% carbon and 2.8% hydrogen.

Considering that this polymer has a structure in which 13r atoms are bonded to both ends of the polymer as represented by the following formula, the average degree of polymerization n calculated from the carbon analysis value is approximately 19, and the polymerization degree n is approximately 19. The average molecular weight of the combined product was approximately 1,720.

Approximately half of this hot chloroform-soluble polymer is chloroform-soluble even at room temperature, and this portion
The number average molecular weight was measured by vapor pressure permeation method using a 17 molecular weight measuring device (manufactured by Haake, West Germany) and chloroform, and found to be about 1,370.

This molecular weight is (considering the structure of formula 31, the average degree of polymerization n
This corresponds to a case where the value of is approximately 14.8.

The average degree of polymerization and weight ratio of the hot chloroform soluble polymer and room temperature chloroform soluble polymer described above (approximately 1:1
), the average degree of polymerization n of the polymer soluble in hot chloroform and insoluble in room temperature chloroform was about 23, and the average molecular weight was about 2,050.

Elemental analysis of the black thermally chloroform-insoluble polymer showed 53.7% carbon and 2.6% hydrogen, but 2.1% by weight of ash was present (this ash was composed of magnesium produced during the polymerization reaction). It is thought that the compound was incorporated into the linear poly(2,5-thennylene) polymer through sulfur coordination.

Therefore, when this ash content is excluded, the elemental analysis values of this polymer are 54.9% carbon and 2.7% hydrogen, and the average degree of polymerization n of this polymer calculated from the carbon analysis values is (3).
Considering the structure of the formula, it is about 30, and the average molecular weight is about 26.
It was 20.

The thermally chloroform-insoluble polymer showed extremely high thermal stability, not melting at 360'C.

The results of thermogravimetric analysis of this polymer conducted under a nitrogen atmosphere are shown in FIG.

From Figure 3, it can be seen that the thermal decomposition of this polymer is 250% under nitrogen atmosphere.
It can be seen that the residual weight starts at around 900°C, but even at a high temperature of 900°C, it shows a residual weight of about 50% by weight.

As shown in Figure 4, the infrared absorption spectrum of this thermally chloroform-insoluble polymer shows one sharp absorption at <788CrrL-1 based on the 2,5-thennylene group in the main chain of the polymer. showed no absorption in the out-of-plane bending vibration region.

Also, C-Br appearing near 960crfL-1
The stretching vibration was even smaller than that of the polymer before hot chloroform extraction.

This term indicates that the thermal chloroform-insoluble polymer has a sufficiently large average degree of polymerization and is composed of regular repeating units, and supports the structure shown in formula (1).

The lower relative proportion of C-Br bonds than in the polymer before hot chloroform extraction indicates that the average degree of polymerization of the hot chloroform-insoluble polymer is greater than that of the polymer before hot chloroform extraction.

Both thermal chloroform-soluble polymers and thermal chloroform-insoluble polymers showed no change in appearance or infrared absorption spectra when left in air at room temperature for one year, and did not show any change in appearance or infrared absorption spectra. It was stable.

Experimental example 2 2,5-dibromothiophene4. '1 (20 mmol)
, dry tetrahydro7 run 20rI'L11 metallic magnesium 0.491 (20 milligram atoms) and 20P
of N1CL, (bpy) was placed in a 200 ml (1) four-day flask and stirred at room temperature under a dry nitrogen atmosphere for 10 hours.

The generated precipitate was collected and washed in the same manner as in Experimental Example 1, and the hot methyl alcohol soluble content was removed using a Soxhlet extractor to obtain a powdery black-brown poly(2.
0.9 (l) of 5-chenylene) polymer was obtained.

This polymer has almost the same stability against oxygen in the air as the hot methyl alcohol-insoluble dark brown polymer obtained in Experimental Example 1, but exhibits almost the same thermal stability and infrared absorption spectrum. It is thought that it has approximately the same average degree of polymerization as the thermal methyl alcohol-insoluble polymer obtained in .

Experimental example 3 2,5-dibromothiophene 4.4? (18 mmol)
was placed in a 200 ml four-day flask, and 20 ml of dry tetrahydrofuran and 44 ml of metallic magnesium
P (18 milligram atoms) was added and reacted for 1 hour with stirring at room temperature under a dry nitrogen atmosphere.

Next, when NiCl214■ was added and stirred, the polymerization reaction started smoothly at room temperature, and a dark brown polymer began to precipitate.

The precipitate formed after reacting for 5 hours at room temperature was
By collecting and washing in the same manner as in Experimental Example 1 and further removing the hot methyl alcohol soluble content using a Soxhlet extractor, 0.90' of a powdery black-brown poly(2,5-chenylene) polymer was obtained. ? I got it.

The elemental analysis of this polymer was 53.2% carbon and 2% hydrogen.
．． 5%, but 1.6% by weight of ash was present.

Therefore, if this ash content is excluded, the elemental analysis value of this polymer is 54.1% carbon and 2.5% hydrogen, and the average degree of polymerization n of this polymer calculated from the elemental analysis value of carbon is ( Considering the structure of formula 3), it was about 24, and the average molecular weight was about 2130.

When this polymer is left in air at room temperature for one year,
No change was observed in the appearance or infrared absorption spectrum, and it was stable against oxygen in the air.

Experimental Example 4 A reaction was carried out in the same manner as in Example 1 without using a catalyst.

However, the polymerization reaction was carried out at room temperature for 1 hour and then further carried out for 4 hours under refluxing of tetrahydrofuran.

The yield of polymer was zero. Experimental Example 5 The reaction was carried out in the same manner as in Comparative Example 1, except that 2,5-dibromothiophene 6.42P (26 mmol), metallic magnesium 6-5Fl (26 mmol), and PdC12 (bpy) 23my were used as the catalyst. I did it.

The yield of polymer was zero. Experimental Example 6 The powder of the dark brown polymer (average degree of polymerization of about 27.5) obtained after extraction with hot methyl alcohol in Experimental Example 1 was solidified under a pressure of 500 kg/crA using an infrared molding machine (manufactured by Shimadzu Corporation). The electrical conductivity of the plate-like material was measured.

The electrical conductivity was 7.3 x 10"Ω-"l' at 18°C.

This polymer powder was exposed to iodine vapor in a glass container at room temperature to absorb iodine for 10 hours to obtain a powder containing 57% by weight of iodine based on the polymer used.

The iodine content was determined from the weight increase upon absorption of iodine.

This powder was solidified in the same manner as described above, and the electrical conductivity of the obtained plate-like material was measured.

Electrical conductivity is 8.8X10'Ω-1・crIL at 18℃
It was 4.6×10”Ω−1·CrrL−1 at −1.80°C.

This semiconductor showed no change in appearance or infrared absorption spectrum when left in air at room temperature for one year, was stable against oxygen in the air, and had virtually no electrical conductivity. There was no significant change.

Experimental Example 7 Powder of the same dark brown polymer (average degree of polymerization of about 27.5) as used in Experimental Example 6 was added to concentrated sulfuric acid at room temperature, and 30
After absorbing sulfuric acid for a minute, thoroughly wash it with methyl alcohol to remove the sulfuric acid adhering to the surface.
A powder containing 35% by weight of 2S04 was obtained.

The sulfuric acid content was determined from the weight increase upon absorption of sulfuric acid.

This powder was solidified in the same manner as in Experimental Example 6, and the electrical conductivity of the obtained plate-like material was measured.

Electrical conductivity is 8.6×10-7Ω-1-Crr at 28℃
L-l, 1.8X10-6Ω-'-CrrL' at 80°C
Met.

When this semiconductor was left in dry air at room temperature for one year, no change was observed in its appearance or infrared absorption spectrum, and it was stable against oxygen in dry air, and its electrical conductivity remained essentially unchanged.

Experimental Example 8 The black thermally chloroform-insoluble polymer (average degree of polymerization of about 30) obtained in Example 1 was solidified in the same manner as in Experimental Example 6,
The electrical conductivity of the obtained plate-like material was measured.

Electrical conductivity is 5.3X10-'1Ω-1・Cr at 18℃
It was fl-1.

This polymer powder was exposed to iodine vapor in the same manner as in Experimental Example 6 to absorb iodine for 10 hours to obtain a powder containing 49% by weight of iodine based on the polymer used.

The iodine content was determined from the weight increase upon absorption of iodine.

This powder was solidified in the same manner as described above, and the electrical conductivity of the obtained plate-like material was measured.

Electrical conductivity is 3.4X10"Ω-1・crrL at 18℃
1.3X10-3Ω-1・crfL-1 at -1,81℃
Met.

This semiconductor showed no change in appearance or infrared absorption spectrum when left in air at room temperature for one year, was stable against oxygen in the air, and had virtually no electrical conductivity. There was no significant change.

[Brief explanation of drawings]

Figure 1 is a graph showing the thermogravimetric analysis results of one example of the linear poly(2,5-thennylene) polymer of the present invention, Figure 2 is its infrared absorption spectrum, and Figure 3 is the linear poly(2,5-thennylene) polymer of the present invention. Poly(
FIG. 4 is a graph showing the results of thermogravimetric analysis of another example of 2,5-thennylene) polymer, and FIG. 4 is an infrared absorption spectrum diagram thereof.

Claims (1)

[Claims] Primary formula: A 2,5-thennylene group represented by the following is used as a repeating unit,
Bonds regularly at the 2nd and 5th positions, with an average degree of polymerization of 14 to 30
A linear poly(2,5-chenylene) polymer characterized by: A repeating unit is a 2,5-thennylene group represented by the following formula:
Bonds regularly at the 2nd and 5th positions, with an average degree of polymerization of 14 to 30
In producing a linear poly(2,5-thennylene) polymer, 2,5-dihalogenation is carried out in a non-reactive solvent in the substantial absence of water using a nickel compound as a catalyst. A method for producing a linear poly(2,5-chenylene) polymer, which comprises reacting thiophene and magnesium.